PLC Electrical in Robotics: Enabling Intelligent Automation

1. Introduction

1.1 Research background and significance

As science and technology develop rapidly, robotics is changing the production mode of various industries at an unprecedented speed. From precise assembly in automobile manufacturing to efficient handling in logistics warehousing, robots are everywhere. However, to realize the intelligent and automated operation of robots, the core lies in their control system. Programmable logic controller (PLC) electrical technology came into being and became the key force to promote the development of intelligent automation of robots.

PLC technology originated in the late 1960s, aiming to solve many drawbacks of traditional relay contactor control systems. At that time, industrial production put forward higher requirements for the flexibility, reliability and scalability of control systems. PLC quickly emerged in the field of industrial control with its programmability, powerful logic processing capabilities and good anti-interference performance. With the continuous advancement of microelectronics technology, computer technology and communication technology, the functions of PLC are becoming increasingly powerful, and the scope of application is constantly expanding, gradually penetrating into the cutting-edge field of robot control.

In the field of robotics, the application of PLC electrical technology is of great significance that cannot be ignored. It greatly improves the reliability and stability of the robot control system. In industrial production environments, there are many factors such as electromagnetic interference and temperature changes, and traditional control systems are easily affected, resulting in frequent failures. PLC uses advanced anti-interference technologies, such as photoelectric isolation and filtering, which can operate stably in harsh environments and ensure the continuity and accuracy of robot work. Taking automobile manufacturing companies as an example, robots on the assembly line need to complete the assembly of parts for a long time and with high precision. The PLC control system can ensure that the robot accurately executes each action instruction in a complex electromagnetic environment, effectively reducing the defective rate and improving production efficiency.

PLC gives robots stronger logical control capabilities. When performing tasks, robots often need to make corresponding decisions based on different conditions and environments. PLC enables robots to quickly process and judge multiple input signals by writing complex logic programs, so as to flexibly adjust their own actions. In logistics warehousing, handling robots need to plan the optimal handling path based on information such as the location and weight of the goods and the layout of the warehouse. The PLC control system can quickly analyze this information and issue precise control instructions to the robot to achieve efficient cargo handling.

Furthermore, the application of PLC technology makes the design and maintenance of robot control systems more convenient. Compared with traditional hard-wired control systems, PLC adopts modular design. Users can choose different modules to combine according to actual needs, which greatly shortens the system development cycle. At the same time, PLC programming uses intuitive and easy-to-understand ladder diagram language, which even non-professional technicians can quickly get started. In terms of system maintenance, PLC has a powerful self-diagnosis function, which can monitor the operating status of the system in real time. Once a fault is found, the problem can be quickly located, reducing maintenance costs and downtime.

From a macro perspective, the widespread application of PLC electrical technology in the field of robotics has a profound impact on promoting the transformation and upgrading of the entire manufacturing industry. It helps to improve production efficiency, reduce production costs, improve product quality, and enhance the competitiveness of enterprises in the global market. With the advent of Industry 4.0 and the era of intelligent manufacturing, PLC electrical technology will play an increasingly important role in the journey of intelligent automation of robots, providing solid support for the realization of intelligent, flexible and efficient industrial production.

1.2 Research objectives and methods

This study aims to deeply analyze the core role mechanism of PLC electrical technology in the process of robot intelligent automation, accurately evaluate its application results, and provide solid theoretical support and practical guidance for promoting the in-depth development and extensive application of this technology in the field of robotics. Specifically, by systematically sorting out the basic principles and unique advantages of PLC electrical technology, comprehensively displaying its application panorama in the field of robot intelligent automation, deeply exploring the challenges faced in the application process, and proposing practical and feasible response strategies, it will help relevant practitioners better grasp the application direction and development trend of PLC electrical technology in the field of robotics.

To achieve the above goals, this study uses a variety of research methods. Case analysis is one of the important means. Through in-depth analysis of typical robot application cases in industries such as automobile manufacturing, logistics warehousing, and electronic assembly, careful observation of the operation of PLC electrical technology in actual scenarios, comprehensive data collection, and in-depth analysis of its specific impact on robot work efficiency, accuracy, stability, etc., first-hand information on the application effect of PLC electrical technology is obtained.

Comparative research methods are also indispensable. A comprehensive comparison is made between the robot control system using PLC electrical technology and the traditional control system, and analysis is carried out from multiple dimensions such as control accuracy, response speed, reliability, and maintenance cost to clarify the advantages and room for improvement of PLC electrical technology compared to traditional technology, providing a reference for further optimization of the technology.

Literature research also plays an important role. We extensively consult relevant academic literature, industry reports, technical standards and other materials at home and abroad, comprehensively sort out the research status and development trends of PLC electrical technology in the field of robots, understand the research results and practical experience of predecessors in this field, provide a solid theoretical foundation for research, avoid duplication of work, and ensure the innovation and cutting-edge nature of research.

1.3 Current research status at home and abroad

In foreign countries, the research and application of PLC electrical technology in the field of robotics started early and achieved remarkable results. The United States has always been a world leader in the field of industrial automation, and its research on the application of PLC in robot control is in-depth and extensive. For example, in the automobile manufacturing industry, Ford Motor Company uses advanced PLC control systems to achieve highly automated collaboration of robots on automobile assembly lines. Through the precise writing of PLC programs, robots can quickly and accurately complete complex tasks such as grasping and assembling parts, greatly improving production efficiency and product quality. Relevant studies have shown that the assembly efficiency of robot production lines controlled by PLCs is more than 30% higher than that of traditional production lines, and the defective rate is reduced by about 20%.

As a manufacturing powerhouse, Germany focuses on high precision and stability in industrial production. Driven by the Industry 4.0 strategy, German companies have deeply integrated PLC technology with robots and applied them to all aspects of smart factories. The high-performance PLC developed by Siemens has powerful computing power and communication functions, and can achieve seamless connection with robots, sensors and other equipment to build a highly intelligent production system. In the field of electronic manufacturing, robots controlled by Siemens PLC can perform precise operations on tiny electronic components with a positioning accuracy of up to ±0.01mm, effectively meeting the electronics industry’s demand for high-precision production.

Japan has unique advantages in robotics technology, and its research on the application of PLC electrical technology in robots focuses on improving the flexibility and versatility of robots. Fanuc’s robot products are widely used in the automotive, mechanical processing and other industries. Equipped with advanced PLC control systems, robots can quickly switch working modes according to different production tasks and realize the automation of various complex processes. In the application of welding robots, the PLC controls the robot’s motion trajectory and welding parameters, which can achieve high-quality welding of workpieces of different shapes and materials, and the weld quality reaches international advanced standards.

Although the research on PLC electrical technology in the field of robotics started relatively late in China, it has developed rapidly in recent years. Many universities and research institutions have actively invested in research in this field and have achieved a series of important results. For example, Harbin Institute of Technology has made significant progress in the research and development of PLC control systems for industrial robots. By optimizing the control algorithm of PLC, the robot’s motion control accuracy and response speed have been improved. Its research results have been put into practical use in the fields of aerospace parts manufacturing, effectively solving the problem of insufficient robot control accuracy in the processing of complex parts.

At the enterprise application level, some large domestic manufacturing companies have also begun to widely adopt PLC electrical technology to improve the automation level of robots. For example, Foxconn Technology Group has introduced a large number of PLC-controlled robots in its production lines to achieve automated production of electronic product assembly. The precise control of robots by PLC not only improves production efficiency, but also reduces labor costs and enhances the competitiveness of enterprises in the international market.

However, there are still some shortcomings in the current research at home and abroad. On the one hand, in terms of communication coordination between PLC and robots, although there are many communication protocols and methods, the stability and real-time performance of communication in complex industrial environments still need to be further improved. When there are a large number of robots and complex tasks, the delay and packet loss of data transmission may affect the operating efficiency of the entire production system. On the other hand, further in-depth research is needed to improve the intelligence of the PLC control system. The current PLC control is mainly based on preset program logic. When facing complex and changing production environments and task requirements, the robot’s autonomous decision-making and adaptive capabilities are relatively weak. How to make the PLC control system have stronger learning ability and intelligent decision-making ability to achieve truly intelligent autonomous control of robots is one of the key directions of future research. In addition, in terms of cross-domain integration, the deep integration of PLC electrical technology with emerging technologies such as artificial intelligence and big data is still in the exploratory stage. How to give full play to the advantages of these technologies and further expand the application scenarios and functions of PLC in the field of robots is also an urgent problem to be solved.

2. PLC electrical technology foundation

2.1 Working Principle of PLC

2.1.1 Input monitoring and data processing

The input monitoring function of PLC is the primary link in achieving automatic control. Through a special input interface, PLC can establish connections with various sensors, switches and other equipment to collect various information about the external environment in real time. These input signals come from a wide range of sources, including temperature values fed back by temperature sensors, pressure data detected by pressure sensors, object position signals captured by photoelectric sensors, and status information of various control switches.

Take temperature sensors as an example. In industrial production, many processes have strict requirements on temperature. For example, in chemical reactions, the precise control of reaction temperature directly affects product quality and production safety. The temperature sensor converts the real-time monitored temperature signal into an electrical signal and transmits it to the input interface of the PLC. At this time, the PLC does not directly use these original signals, but performs a series of data processing. First, the signal is sampled to convert the continuously changing analog signal into a discrete digital signal for subsequent digital processing. Then, a filtering algorithm is used to remove noise interference in the signal to ensure the accuracy of the data. Because in the actual industrial environment, there are a lot of electromagnetic interference, electrical noise, etc. These interferences may cause sensor signal distortion. If not processed, it will seriously affect the control decision of the PLC.

After sampling and filtering the input signal, the PLC will perform preliminary analysis and judgment on the data according to the preset program. For example, in a temperature control system, the PLC will compare the collected real-time temperature value with the preset temperature range to determine whether the current temperature is in the normal working range. If the temperature exceeds the set range, the PLC will mark and store this information, waiting for further analysis and decision-making in the subsequent logic processing stage. This real-time monitoring and data processing of input signals provides a reliable data basis for the subsequent logic operations and control decisions of the PLC, ensuring that the control system can accurately perceive changes in the external environment and respond in a timely manner.

2.1.2 Logic Programming and Decision Making

Logic programming is one of the core functions of PLC, which gives PLC powerful decision-making ability. Users use programming software to write detailed logic programs for PLC based on actual control needs, using programming languages such as ladder diagrams, instruction tables, and function block diagrams. These programs are like the “brain instructions” of PLC, enabling it to make accurate control decisions based on input data.

In the material handling system of an automated production line, the role of logic programming is fully reflected. Assume that there are multiple sensors in the system to detect the location, presence, and working status of the material handling robot. When the material is transported to the specified location, the position sensor will send a signal to the PLC. After receiving the signal, the PLC will make a judgment based on the pre-written logic program. If other conditions are met at the same time, such as the handling robot is in an idle state and there is no material blocking the target storage location, the PLC will start the grabbing action instruction of the handling robot. This process involves the logical operation of multiple input signals. The PLC uses logical operators such as “AND”, “OR”, and “NOT” to comprehensively analyze these signals. For example, only when the material position signal is “material present”, the robot status signal is “idle”, and the target position signal is “unblocked” and the three conditions are met at the same time (that is, the “AND” operation is performed), the PLC will output a control signal to start the robot’s grabbing action.

In complex industrial control scenarios, PLCs may also need to perform complex logical operations such as loop control and conditional judgment. For example, in a factory with multiple production modes, PLCs need to dynamically adjust control strategies based on factors such as the selection of production tasks and the operating status of equipment. By writing nested conditional judgment statements and loop programs, PLCs can achieve precise control of different production processes. When performing logical operations, the PLC’s central processing unit (CPU) quickly processes the instructions in the program, and based on different combinations of input data, it draws corresponding decision results in a very short time, providing a basis for subsequent output control.

2.1.3 Output Control and Execution

Output control is the key step for PLC to convert decision results into actual control actions. When PLC completes the logical operation of input data and makes a decision, it will send corresponding control signals to the actuators through the output interface to drive these actuators to implement specific control actions, thereby completing the control task of external devices.

Common actuators include motors, solenoid valves, relays, etc. Taking motors as an example, in industrial automation production, motors are widely used in material transportation, mechanical processing and other links. When the PLC determines that the motor needs to be started for material transportation, it will send an electrical signal to the output interface connected to the motor. For AC motors, the PLC may energize the coil of the control contactor to close the main contacts of the contactor, thereby connecting the power supply of the motor and starting the motor to run. For DC motors, the PLC can accurately control the speed and direction of the motor by adjusting the voltage or current of the output signal to meet different production needs.

In some occasions that require high control accuracy, such as the processing of CNC machine tools, PLC will output precise pulse signals to control the movement of the motor. By controlling the frequency and number of pulses, the rotation angle and displacement of the motor can be accurately controlled, and the precise positioning and motion control of the machine tool can be achieved, ensuring the processing of high-precision parts.

Solenoid valves also play an important role in industrial control. For example, in pneumatic control systems, PLC controls the flow direction and pressure of compressed air by controlling the on and off of the solenoid valve, thereby driving the cylinder to achieve various mechanical actions, such as grabbing, transporting, and sorting of materials. When the PLC outputs a control signal to energize the solenoid valve, the valve core of the solenoid valve moves, changing the connection state of the air path, allowing compressed air to enter the corresponding cylinder, pushing the cylinder piston to move, and completing the predetermined operation task.

Relays are often used to control the switching of circuits. PLC can indirectly control high-voltage and high-current circuits by controlling the on and off of the relay coils. In the control systems of some large equipment, PLC uses relays to control the power switch of the main circuit, the start and stop of the lighting circuit, etc., to ensure the safe operation and normal operation of the equipment.

2.2 PLC Hardware Composition

2.2.1 Processor (CPU)

As the core component of PLC, the processor (CPU) is like the human brain, playing an irreplaceable key role in the entire system. It is responsible for executing the program written by the user, processing the input data quickly and accurately, and generating corresponding control instructions according to the preset logic to command other components of PLC to work together to ensure the efficient and stable operation of the entire control system.

There are significant differences in performance between different types of CPUs, and these differences have a profound impact on key performance indicators such as the processing power, operating speed, and response time of PLCs. In the field of industrial automation, high-end PLCs are usually equipped with high-performance CPUs, such as some CPUs with multi-core architecture and high-speed cache technology. Taking the CPU of Siemens S7-1500 series PLC as an example, it uses advanced multi-core processor technology and can process multiple task threads at the same time, greatly improving the parallelism of data processing. In complex industrial production scenarios, such as automated production lines in automobile manufacturing, a large number of sensors collect data such as equipment operating status and workpiece position in real time. The CPU of this series of PLCs can quickly process and analyze these massive data, make decisions quickly, and control robots to accurately complete the assembly tasks of parts. In contrast, the CPU used by mid- and low-end PLCs has relatively weak performance and is suitable for some simple control scenarios that do not require high data processing speed and accuracy, such as material conveying systems in small factories. Only a small number of sensor signals need to be simply judged and controlled by simple logic, and mid- and low-end CPUs can meet their needs.

The CPU’s computing speed is also an important indicator of its performance. A CPU with a fast computing speed can complete a large number of logical operations and data processing tasks in a very short time, allowing the PLC to quickly respond to changes in external signals. In a high-speed packaging production line, the packaging speed of the product is very fast, and the PLC needs to process the information such as the product position detected by the sensor and the conveying status of the packaging material in real time, and control the actuator to complete the packaging action in time. At this time, the PLC equipped with a high-speed CPU can quickly process this data to ensure the accuracy and efficiency of the packaging action, and avoid packaging errors or material waste.

In addition, the storage capacity of the CPU also has an important impact on the performance of the PLC. A larger storage capacity can store more user programs, data, historical records and other information. In some industrial processes that require long-term operation and high data recording requirements, such as reaction process monitoring in chemical production, the PLC needs to store a large amount of real-time data such as temperature, pressure, flow, and control programs. A CPU with large storage capacity can meet this demand, ensure the integrity and traceability of the data, and provide strong support for subsequent production analysis and troubleshooting.

2.2.2 Input/Output Modules

The input/output (I/O) module is a bridge for information exchange between PLC and external devices, and its function is crucial. Through the I/O module, PLC can collect various status information of external devices in real time, and output the processed control signal to the corresponding actuator, thereby realizing precise control of external devices.

I/O modules can be divided into analog modules and digital modules, each with its own characteristics in terms of function and application scenarios. Digital modules are mainly used to process discrete switch signals, such as button pressing and releasing, sensor triggering and non-triggering, relay energization and release, etc. In industrial production, digital modules are widely used in equipment start-stop control, status monitoring, etc. For example, on an automated assembly line, digital input modules are used to collect sensor signals at each workstation to determine whether the workpiece is in place; digital output modules are used to control the start and stop of the motor, the extension and retraction of the cylinder, and other actions to achieve automated operation of the production line.

The analog module is mainly used to process continuously changing analog signals, such as the output signals of sensors such as temperature, pressure, flow, and liquid level. These analog signals need to be converted by A/D (analog/digital) before they can be processed by the CPU of the PLC. In the temperature control system, the analog input module converts the continuously changing analog temperature signals detected by the temperature sensor into digital signals and transmits them to the CPU. After the CPU analyzes and processes these data according to the preset control strategy, it outputs the corresponding analog signals through the analog output module to control the operation of the heating equipment or cooling equipment to achieve precise temperature regulation.

In practical applications, it is very important to select the appropriate I/O module according to the specific control requirements. First of all, the demand for I/O points needs to be considered. Different industrial control systems have different requirements for the number of input and output signals. Modules with corresponding I/O points should be reasonably selected according to the actual number of sensors and actuators. If the number of I/O points is too small, it may not meet the control requirements of the system; if it is too large, it will cause waste of resources and increase costs.

Secondly, consider the type and range of the signal. Different sensors and actuators output or require different signal types and ranges. For example, a temperature sensor may output a 4-20mA current signal or a 0-5V voltage signal, and a pressure sensor also has a variety of range options. Therefore, when selecting an I/O module, you must ensure that it is compatible with the signal type and range that needs to be processed to ensure accurate signal transmission and processing.

Signal transmission distance and anti-interference ability are also important factors to consider when selecting I/O modules. In some large industrial sites, the distance between sensors and actuators and PLCs may be far. At this time, it is necessary to select I/O modules with strong signal transmission capabilities and anti-interference performance to ensure that the signal is not distorted or lost during transmission. For example, I/O modules using fiber optic transmission technology can effectively improve the transmission distance and anti-interference ability of signals, and are suitable for industrial control applications in long-distance and high-interference environments.

2.2.3 Power Supply

Stable power supply is the basic guarantee for the normal operation of PLC, and its importance is self-evident. As the core equipment of industrial automation control system, PLC needs to work continuously and reliably in various complex industrial environments. Once there is a problem with the power supply, such as voltage fluctuation, power outage, etc., it may cause PLC to work abnormally or even damage the equipment, thus affecting the normal operation of the entire production process and causing huge economic losses.

The power module of PLC usually has multiple features to meet different application requirements. It can convert the external input AC power into various DC power required by the PLC, providing stable power support for various components such as CPU, memory, I/O module, etc. The power module has good voltage stabilization performance and can automatically adjust the output voltage within a certain range to ensure that the PLC can still work normally when the input voltage fluctuates. In some industrial sites, the grid voltage may fluctuate due to load changes and other reasons. High-quality power modules can effectively suppress such fluctuations, ensure the stability of the output voltage, and create good power conditions for the reliable operation of the PLC.

The power module also has functions such as overcurrent protection, overvoltage protection and short-circuit protection. When the power output current exceeds the rated value, the overcurrent protection function will start to cut off the power output to prevent the internal circuit of the PLC from being damaged by excessive current; when the overvoltage protection function detects that the input voltage is too high, it will take corresponding measures, such as reducing the voltage or cutting off the power supply, to protect the PLC from the impact of high voltage; and the short-circuit protection function can act quickly when a short circuit occurs in the output circuit to prevent the short-circuit current from damaging the equipment.

In addition, in order to ensure that the PLC can save data and status normally in the event of a sudden power outage, some power modules are also equipped with a backup battery. When the main power is cut off, the backup battery immediately starts working to provide a short period of power support for the PLC, so that the PLC has enough time to save important data and operating status to non-volatile memory, so that it can quickly return to the working state before the power outage after the power is restored, ensuring the continuity of the production process. In some industries that have extremely high requirements for production continuity, such as petrochemicals, steel manufacturing, etc., the backup battery function of the power module is particularly important, which can effectively avoid production interruptions and equipment damage caused by short power outages.

2.3 PLC software system

2.3.1 Programming Language

PLC programming languages are rich and varied, each with its own unique characteristics and applicable scenarios, providing engineers with flexible programming options to meet the needs of different industrial control projects.

Ladder Diagram (LD) is one of the most commonly used and intuitive programming languages. It draws on the form of traditional electrical control circuit diagrams and uses graphic symbols such as relays and contacts to represent logical relationships. In the ladder diagram, normally open contacts and normally closed contacts are represented by different graphics, and these contacts and coils are combined and connected to form a logical control loop. This programming method is very easy to use for engineers familiar with electrical control, because its logical relationship is clear at a glance, just like drawing an actual electrical control circuit diagram. In a simple motor forward and reverse control program, the use of ladder diagrams can clearly show the control logic of the motor’s forward, reverse, and stop. By reasonably connecting the normally open and normally closed contacts of the control button with the coils of the motor’s forward and reverse contactors, the forward and reverse control function of the motor can be intuitively realized.

Function Block Diagram (FBD) is a graphical programming language based on functional modules. It decomposes complex control functions into independent functional blocks, each of which has specific inputs, outputs and functions. These functional blocks are similar to integrated circuit modules in electronic circuits. By combining and connecting them, complex control logic can be realized. The advantage of the function block diagram is that it can clearly express the functional structure and data flow of the system, which facilitates the modular design and analysis of the system. In the control system of the automated production line, multiple links such as material transportation, processing, and testing are involved, and each link can be represented by a function block. By connecting these function blocks according to the production process, the control system of the entire production line can be quickly built, and each function block can be debugged and optimized separately.

Instruction List (IL) is a text-based programming language that uses mnemonics to represent various operating instructions, similar to computer assembly language. The instruction list language is concise and compact, and can implement complex logical operations and data processing. For some control tasks that require high program execution efficiency and complex logical relationships, the instruction list language can play its advantages. In some industrial scenarios that require rapid processing and analysis of large amounts of data, such as real-time monitoring and analysis of various data in the production process, programs written in instruction list language can complete data processing tasks more efficiently. However, the readability of the instruction list language is relatively poor. For beginners, it is difficult to understand and write, and requires an in-depth understanding of the PLC instruction system.

Structured Text (ST) is a high-level text programming language with a syntax similar to PASCAL. It supports high-level programming structures such as variables, data types, conditional judgments, and loop control. Structured text is suitable for writing complex algorithms and logic programs, and can achieve refined control of the system. In some industrial applications that require complex mathematical operations and logical reasoning, such as robot path planning and motion control algorithm implementation, structured text can provide powerful programming capabilities. It can easily define and use various data structures and algorithms, making the logic of the program clearer and more concise, and improving the readability and maintainability of the program.

Sequential Function Chart (SFC) is a programming language used to describe the sequential control process of the control system. It divides the system’s working process into a series of steps and transition conditions, and realizes the sequential control of the system by switching steps and satisfying transition conditions. The sequential function chart can clearly show the system’s workflow and state transition relationship. For some control tasks with obvious sequentiality, such as process control of automated production lines and elevator operation control, programming with sequential function charts can make the program structure clearer, easier to understand and maintain. In the elevator control system, the sequential function chart can intuitively describe the order and conditions of a series of actions of the elevator from receiving floor call signals, rising or falling, reaching the target floor, opening doors, closing doors, etc., to ensure the safe and stable operation of the elevator.

2.3.2 Programming software and tools

PLC programming software and tools are important means to achieve PLC program development, debugging and maintenance. PLCs of different brands and models are usually equipped with corresponding dedicated programming software. These software have their own characteristics and provide engineers with rich functional support.

Siemens’ SIMATIC STEP 7 is a programming software widely used in Siemens series PLCs, with powerful functions and high flexibility. It supports multiple programming languages, including ladder diagrams, function block diagrams, instruction lists, etc., to meet the programming habits and project requirements of different engineers. The software provides an intuitive user interface, and engineers can easily create, edit, debug and monitor programs through graphical operations. When creating a complex automation control system program, engineers can use the graphical programming interface of SIMATIC STEP 7 to easily draw ladder diagrams or function block diagrams and quickly build the framework structure of the program. At the same time, the software also has powerful diagnostic functions, which can monitor the operating status of the PLC in real time, promptly discover and locate errors and faults in the program, and greatly improve the debugging efficiency.

RSLogix 5000 from Rockwell Automation is programming software for its Allen-Bradley series of devices, especially for complex automation projects. The software provides a comprehensive solution that supports object-oriented programming, allowing engineers to organize and manage program code more efficiently. RSLogix 5000 also has mature security functions to ensure that programs run safely and reliably in industrial production environments. It integrates seamlessly with the FactoryTalk integrated environment, can achieve a high degree of integration with other automation equipment and systems, and provides strong support for building large and complex automation control systems.

CX-Programmer from Omron is a programming software for Omron PLCs, known for its user-friendly interface and efficient programming capabilities. It provides users with an intuitive engineering environment, and simplifies the program writing process through convenient methods such as drag-and-drop operations. For beginners, CX-Programmer provides a large number of sample programs and detailed help documents to help quickly get started and learn. In actual projects, engineers can use these sample programs as references, combined with specific control requirements, to quickly write and debug their own programs. At the same time, the software also supports multiple communication protocols, which facilitates data interaction and communication with other devices.

In addition to the above-mentioned dedicated programming software, there are also some general PLC programming tools, such as CODESYS. CODESYS is a powerful development environment that supports the development of multiple PLC brands and has high versatility and portability. It provides a wealth of programming functions and library functions. Engineers can choose appropriate functional modules for development according to project requirements, reducing the workload of repeated programming. CODESYS also supports online debugging and monitoring functions, allowing engineers to view the program’s running status and variable values in real time, and discover and solve problems in a timely manner.

2.3.3 Programming Methods

In PLC programming, adopting appropriate design methods can improve the quality, readability and maintainability of the program, and ensure the stable operation and efficient work of the control system. Structured programming and modular programming are two commonly used programming methods, which play an important role in PLC programming.

Structured programming is a programming method based on three basic structures: sequence, selection and loop. By organizing and constructing the program logic according to these three structures, the program has a clear hierarchy and logical flow. In the sequence structure, the program executes each statement in order from top to bottom; the selection structure determines the execution of different program branches based on different conditions; the loop structure is used to repeatedly execute a specific program code until a specific end condition is met. In the PLC programming of a temperature control system, a structured programming method can be used. First, the temperature sensor data is collected and read through the sequence structure; then, the collected temperature value is compared with the preset temperature range using the selection structure to determine whether the current temperature is normal. If the temperature is out of range, the corresponding control operation is selected according to different situations, such as starting the heating device or cooling device; finally, the loop structure is used to continuously monitor and control the temperature to ensure that the temperature always remains within the set range.

Modular programming is to divide the entire control system into multiple independent modules according to function. Each module is responsible for completing specific functional tasks, and the modules transmit and interact with each other through interfaces. The advantage of this programming method is that it improves the maintainability and scalability of the program. When the control system needs to be upgraded or modified, only the corresponding module needs to be adjusted without affecting the normal operation of other modules. In a PLC control system of an automated production line, it can be divided into multiple functional modules such as material conveying module, processing module, and detection module. The material conveying module is responsible for controlling the transportation of materials on the production line, the processing module realizes the processing of materials, and the detection module is used to perform quality inspection on the processed products. Each module has independent input and output interfaces and program logic. By reasonably calling and combining these modules, the control system of the entire production line can be quickly constructed. In the later maintenance process, if the material conveying module fails, the engineer can directly check and repair the module without large-scale troubleshooting of the entire program.

In actual PLC program design, structured programming and modular programming methods are usually combined. First, modular programming is used to divide the system into multiple functional modules, and then structured programming methods are used within each module to implement the specific functional logic of the module. This not only ensures that the overall structure of the program is clear and easy to maintain, but also improves the readability and scalability of the program, providing a strong guarantee for the stable operation and efficient development of the PLC control system.

3. Application of PLC electrical technology in robots

3.1 Application in Industrial Robots

3.1.1 Automobile manufacturing

In the field of automobile manufacturing, industrial robots are widely used, and PLC electrical technology plays a pivotal role in it. Taking automobile welding robots as an example, their working process involves highly precise motion control and complex logical judgment. PLC, with its powerful functions, realizes precise welding control and efficient coordination of production processes.

In the automobile body welding production line, there are usually multiple welding robots working together. Each welding robot needs to accurately locate the various welding parts of the car body and perform welding operations according to the preset welding process parameters. PLC can accurately control the movement trajectory of the robot’s arm by working closely with the robot’s motion control system. When welding the car door, the PLC sends precise pulse signals to the robot’s servo motor according to the pre-written program to control the motor’s speed and angle, so that the robot’s welding gun can accurately move to the welding point of the car door. At the same time, the PLC can also monitor the robot’s movement status in real time to ensure that its movement accuracy is within the allowable error range. Once the robot’s movement is found to be deviated, the PLC will immediately issue an adjustment instruction to ensure the welding quality.

Parameter control during the welding process is also crucial. Parameters such as welding current, voltage, and welding speed directly affect the welding quality. Through communication connection with the welding power supply, PLC can adjust welding parameters in real time according to different welding locations and materials. For welding of high-strength steel, PLC will increase the welding current according to the preset process requirements to ensure the strength and quality of the weld. Moreover, during the welding process, PLC will continue to monitor changes in welding parameters. If it finds excessive current fluctuations or abnormal voltage, it will take timely measures to adjust to avoid welding defects.

PLC also plays a key role in coordinating the production process. Automobile manufacturing is a highly automated production process, and welding robots need to work in conjunction with other production equipment, such as conveyor lines and fixtures. PLC communicates with the control systems of these devices to achieve seamless integration of the entire production process. When the car body is transported to the welding station, the PLC controls the fixture to accurately clamp the car body and provide a stable working platform for the welding robot. After welding is completed, the PLC controls the conveyor line to transport the welded car body to the next station. In this way, PLC ensures the efficient and stable operation of the entire production process, improving the production efficiency and quality of automobile manufacturing.

3.1.2 Electronics manufacturing field

In the field of electronic manufacturing, with the development trend of miniaturization and refinement of electronic products, the requirements for production accuracy and efficiency are becoming increasingly stringent. The application of PLC electrical technology in electronic component assembly robots provides strong support for meeting these requirements and significantly improves production accuracy and efficiency.

Electronic components are usually small in size, such as chips, resistors, capacitors, etc., and their assembly process requires extremely high precision. Taking the assembly of SMD components on mobile phone motherboards as an example, the assembly robot needs to accurately place the tiny SMD components on the designated position of the motherboard. PLC achieves precise control of the assembly robot by working in conjunction with high-precision visual systems and motion control systems. The visual system is responsible for image acquisition and recognition of electronic components and motherboards, and obtains the position, posture of components and the position information of welding points on the motherboard. After this information is transmitted to the PLC, the PLC performs precise calculations and analysis according to the preset algorithm, and then sends control instructions to the robot’s motion control system. The motion control system accurately controls the movement of the robot’s mechanical arm according to these instructions, enabling the mechanical arm to grab and place electronic components with extremely high precision. In this process, the PLC can achieve micron-level position control accuracy of the mechanical arm, ensuring the accurate assembly of electronic components.

PLC can also improve assembly efficiency by optimizing the robot’s motion path and action sequence. During the electronic component assembly process, the robot needs to frequently move between different locations to grab and place components. PLC analyzes the assembly task and rationally plans the robot’s motion path, avoiding unnecessary movements and travel, and reducing the robot’s movement time. At the same time, PLC can also optimize the robot’s action sequence according to the type and quantity of components, so that the robot can complete the assembly task in the most efficient way. In an assembly task involving multiple types of electronic components, PLC can prioritize the robot to grab and place components that are close to each other according to the distribution of components, reducing the robot’s idle travel time. In this way, PLC effectively improves the work efficiency of electronic component assembly robots and shortens the production cycle.

In addition, PLC also has powerful fault diagnosis and alarm functions. In the electronic manufacturing process, once a fault occurs, a large number of products may be scrapped, causing huge economic losses. PLC can monitor the operating status of the robot and the working conditions of each component in real time. Once an abnormality is found, such as motor overheating, sensor failure, etc., it will immediately issue an alarm signal and take corresponding measures to deal with it. PLC can automatically stop the operation of the robot to prevent the fault from further expanding, and record the fault information at the same time, providing maintenance personnel with accurate fault diagnosis basis, greatly shortening the troubleshooting time and improving the reliability and stability of the production line.

3.1.3 Logistics and warehousing

In the field of logistics and warehousing, logistics handling robots are increasingly used, and PLC electrical technology provides key support for their efficient operation. Through the case analysis of logistics handling robots, we can clearly see the important control role of PLC in robot path planning, cargo handling, etc.

In modern logistics warehouses, logistics handling robots need to accurately find the storage location of goods in complex environments and transport them to designated locations. PLC plays a core role in the path planning of robots. Take AGV (automatic guided vehicle) as an example. It is usually equipped with multiple navigation methods such as laser navigation, visual navigation or magnetic strip navigation. When AGV receives a handling task, PLC first obtains the map information of the warehouse and the location information of the goods. Then, based on this information, PLC uses advanced path planning algorithms such as A* algorithm and Dijkstra algorithm to calculate the optimal path from the current location to the storage location of the goods. During the calculation process, PLC will consider factors such as the distribution of obstacles in the warehouse, the width of the channel, and the operation of other robots to ensure that the planned path is safe and efficient. In a large logistics warehouse, there are many shelves and channels set up in the warehouse, as well as other handling equipment in operation. When AGV needs to transport goods, PLC will plan an optimal path to avoid obstacles and other equipment based on the warehouse map and real-time environmental information, so that AGV can reach the storage point of goods quickly and accurately.

During the cargo handling process, the PLC can accurately control the robot’s movements. Logistics handling robots are usually equipped with actuators such as manipulators and grippers to grab and carry cargo. PLC is connected to the control system of these actuators, and can accurately control the movement trajectory of the manipulator and the gripping force of the grippers according to the shape, weight and handling requirements of the cargo. For cargo of different sizes and weights, the PLC will adjust the movement speed and acceleration of the manipulator to ensure a smooth and safe handling process. When handling fragile cargo, the PLC will control the grippers to grab the cargo with appropriate force to avoid damage to the cargo due to over-tight grip; at the same time, the PLC will control the movement speed of the manipulator to be slower to prevent damage to the cargo due to shaking during handling.

In addition, PLC can also realize the coordinated control of multiple logistics handling robots. In large-scale logistics warehousing scenarios, there are often multiple handling robots working at the same time. PLC connects to each robot through the communication network to monitor their working status and task progress in real time. According to the logistics needs of the warehouse, PLC can reasonably allocate handling tasks to different robots to avoid conflicts and congestion between robots and improve the operating efficiency of the entire logistics warehousing system. During peak hours, the warehouse needs to handle a large number of goods in and out of the warehouse at the same time. PLC will reasonably allocate tasks according to the location, load and task priority of each robot, so that each robot can work efficiently and ensure the smooth progress of logistics warehousing operations.

3.2 Application in special robots

3.2.1 Emergency rescue robot

In the field of disaster relief and rescue, facing dangerous and complex environments such as fire scenes, earthquake ruins, and nuclear leakage areas, disaster relief and rescue robots play an irreplaceable key role, and PLC electrical technology is the core support for their stable and efficient operation.

Take earthquake rescue scenarios as an example. After an earthquake, buildings collapse and there are a large number of unstable structures and dangerous items in the ruins. In this harsh environment, the rescue robot needs to go deep into the ruins to search for survivors and carry out rescue work. PLC can sense changes in the surrounding environment in real time by working closely with the robot’s sensor system. For example, infrared sensors are used to detect signs of life in the ruins. When the sensor detects infrared signals emitted by the human body, it transmits the signal to the PLC. After receiving the signal, the PLC analyzes and judges according to the preset program, determines the specific location of the signs of life, and plans the best rescue path. At the same time, the PLC also controls the robot’s mechanical arm so that it can accurately move obstacles and approach survivors.

At the fire scene, high temperature, thick smoke and toxic gases pose a great threat to the life and safety of rescue workers. The rescue robot is equipped with high temperature and smoke resistant equipment. PLC works with these equipment to achieve effective intervention at the fire scene. PLC can control the robot to carry fire extinguishing equipment and accurately adjust the amount and direction of the fire extinguishing agent according to the size and distribution of the fire. When approaching the fire source, PLC will also monitor the robot’s temperature and gas sensor data in real time. Once the temperature is too high or the concentration of harmful gases exceeds the standard, it will immediately control the robot to evacuate to a safe area to ensure its own safety.

In a nuclear leak accident, rescue robots need to perform tasks in a high-radiation environment. The anti-interference ability and stability of PLC are fully demonstrated in this extreme environment. It can reliably control various actions of the robot, such as blocking the leak source and cleaning up radioactive materials. Through remote control technology, operators can issue instructions to the robot through PLC from a safe distance, avoiding direct exposure of personnel to a high-radiation environment, greatly improving the safety and feasibility of rescue work.

3.2.2 Medical assistance robots

In the medical field, the application of PLC electrical technology in medical-assisted robots has brought revolutionary changes to medical services, significantly improved the accuracy and safety of medical services, and provided strong guarantees for patients’ treatment and rehabilitation.

Take surgical robots as an example. When performing complex surgical operations, the requirements for surgical precision are extremely high. PLC achieves precise control of surgical instruments by cooperating with the robot’s high-precision mechanical arm and sensor system. In brain surgery, surgical robots need to perform extremely delicate operations in a small space to avoid damaging surrounding nerve tissue. According to the surgical plan and real-time image feedback, the PLC sends precise control instructions to the servo motor of the mechanical arm, enabling the mechanical arm to move surgical instruments with micron-level precision and accurately remove diseased tissue. At the same time, the PLC can also monitor the position and force of surgical instruments in real time to ensure the safety and stability of the surgical process. If the position of the mechanical arm deviates or the force applied is too large during the operation, the PLC will immediately sound an alarm and automatically adjust the movement of the mechanical arm to avoid harm to the patient.

In the field of rehabilitation therapy, rehabilitation robots are increasingly being used. For patients with limb dysfunction due to stroke, spinal cord injury and other reasons, rehabilitation robots can help them conduct targeted rehabilitation training. PLC plays an important role in controlling training movements and monitoring patient status in rehabilitation robots. Rehabilitation robots can develop personalized training plans based on the patient’s condition and rehabilitation stage. According to these plans, PLC controls the robot’s mechanical structure to simulate various rehabilitation movements, such as walking and grasping. At the same time, PLC will also monitor the patient’s muscle strength, joint range of motion and other physiological indicators in real time through sensors, and adjust the training intensity and movement mode according to the monitoring results to ensure the effectiveness and safety of rehabilitation training. If the patient becomes tired or uncomfortable during training, the sensor will transmit the signal to PLC, which will adjust the training rhythm or suspend the training in time to ensure the safety of the patient.

In addition, in terms of medical logistics and distribution, PLC-controlled logistics robots can efficiently and accurately transport medicines, medical equipment, specimens and other items within the hospital. These robots can autonomously shuttle between various departments of the hospital through preset path planning and navigation systems. PLC reasonably dispatches the operation of robots according to the logistics needs of the hospital and real-time traffic conditions, avoids collisions and congestion between robots, and improves the efficiency and accuracy of logistics and distribution. During the transportation process, PLC will also monitor the operating status of the robot and the safety of the goods in real time to ensure that the goods can be delivered to the destination safely and in a timely manner.

3.2.3 Agricultural robots

In the field of agricultural production, with the rising labor costs and the continuous improvement of agricultural production efficiency and quality requirements, the application of agricultural operation robots has gradually become an important trend in the development of agricultural modernization. The application of PLC electrical technology in agricultural operation robots has brought significant changes to agricultural production and strongly promoted the automation and intelligentization of agricultural production.

Take the orchard picking robot as an example. During the fruit picking process, it is necessary to accurately identify the maturity, position and shape of the fruit and perform precise picking operations. The PLC works in conjunction with the robot’s visual recognition system and robotic arm to achieve efficient fruit picking. The visual recognition system uses a camera to capture images of the fruit in the orchard and transmits the image information to the PLC. The PLC uses a built-in image processing algorithm to analyze and identify the image to determine the maturity and position of the fruit. When a ripe fruit is identified, the PLC calculates the motion trajectory of the robotic arm based on the position information of the fruit and sends control instructions to the drive motor of the robotic arm so that the robotic arm can accurately grab the fruit. During the grabbing process, the PLC will also adjust the grabbing force of the robotic arm according to the shape and size of the fruit to avoid damage to the fruit. At the same time, the PLC can also communicate with the orchard’s management system and upload picking data in real time, such as the type, quantity, and location of the picked fruit, to provide data support for the orchard’s production management.

In the weeding operation of farmland, the agricultural weeding robot can automatically weed according to the distribution of weeds in the farmland. PLC achieves precise weeding control by cooperating with the robot’s sensor system and weeding actuator. The sensor system can monitor the growth of weeds in the farmland in real time, including information such as the type and distribution density of weeds. Based on this information, PLC formulates weeding strategies and controls the work of weeding actuators. For example, for large areas of weeds, PLC can control the weeding robot to weed at a higher speed; for scattered weeds, PLC can control the robot to weed accurately at a fixed point to avoid damage to crops. In addition, PLC can also adjust the robot’s driving speed and posture according to the terrain and soil conditions of the farmland to ensure the stability and efficiency of weeding operations.

In the field of agricultural irrigation, irrigation robots can automatically perform irrigation operations based on factors such as soil moisture and crop water requirements. PLC realizes intelligent irrigation control by connecting with soil moisture sensors, meteorological sensors and irrigation equipment. Soil moisture sensors monitor soil moisture information in real time, while meteorological sensors provide weather conditions, such as temperature and rainfall. Based on this information, combined with the growth stage and water demand of crops, PLC calculates the reasonable irrigation amount and irrigation time, and controls the opening and closing of irrigation equipment. For example, when the soil moisture is lower than the set threshold and the weather forecast shows no rainfall in the near future, PLC will control the irrigation equipment for irrigation; when the soil moisture reaches the appropriate range or the rainfall is large, PLC will stop irrigation in time to avoid waste of water resources. Through this intelligent irrigation control, not only the utilization efficiency of water resources is improved, but also a suitable growth environment can be provided for crops to promote the growth and development of crops.

3.3 Application in service robots

3.3.1 Home Service Robot

In modern family life, home service robots are gradually becoming people’s right-hand men, bringing people a more convenient and comfortable life experience. Take the sweeping robot as an example. With its efficient cleaning ability and intelligent operation, it has been favored by consumers, and this is inseparable from the strong support of PLC electrical technology.

During the operation of the sweeping robot, the autonomous navigation function is the key to its efficient cleaning. By working in conjunction with a variety of sensors, the PLC can obtain information about the robot’s surrounding environment in real time. For example, the laser radar sensor can quickly scan the surrounding space and draw a detailed map, and the ultrasonic sensor can detect the distance and position of obstacles in front. The PLC integrates and analyzes the data from these sensors, and uses advanced algorithms to plan the optimal cleaning path to ensure that the robot can fully and efficiently cover the entire cleaning area and avoid omissions and repeated cleaning. In a complex living room environment, there are sofas, coffee tables, TV cabinets and other furniture. After the sweeping robot obtains the location information of these furniture through sensors, the PLC will quickly plan a cleaning path that avoids obstacles, starting from the corner of the room and cleaning line by line in a certain order to ensure that every inch of the floor can be cleaned.

PLC also plays an important role in the execution of cleaning tasks. It can accurately control the various cleaning components of the sweeping robot, such as the motor-driven roller brush and side brush, and the fan responsible for vacuuming. When the robot detects dust or garbage on the ground, the PLC will automatically adjust the speed of the roller brush and side brush according to the type and amount of garbage to ensure that the garbage can be effectively cleaned. For stubborn stains, the PLC can control the roller brush to increase the pressure on the ground to enhance the cleaning effect. At the same time, the PLC can also reasonably adjust the suction power of the fan according to the size of the cleaning area and the amount of garbage, reducing energy consumption and extending the robot’s battery life while ensuring the cleaning effect.

In addition, PLC also gives the sweeping robot intelligent charging management functions. When the robot detects that the battery is low, the PLC will plan an optimal path to the charging station based on the pre-stored map information to ensure that the robot can accurately return to the charging station for charging. During the charging process, the PLC will monitor the battery charging status in real time. When the battery is full, it will automatically stop charging to avoid damage to the battery due to overcharging and extend the battery life.

3.3.2 Hotel service robots

In the hotel industry, improving service quality and efficiency is the key to attracting customers and enhancing competitiveness. The application of PLC electrical technology in hotel service robots has brought innovative changes to the hotel’s operating model and greatly improved the quality and efficiency of services.

Hotel service robots usually undertake a variety of tasks, such as guiding guests, transporting luggage, and delivering items. In terms of guiding guests, when guests enter the hotel lobby, the guiding robot can identify the guest through face recognition technology, and interact with the hotel’s customer management system to obtain the guest’s reservation information and room number. Then, the PLC plans an optimal route to the guest’s room based on this information, and controls the robot to guide the guest to the room through voice and gestures. During the guidance process, the robot will monitor the surrounding environment in real time to avoid collisions with other people or objects. If an elevator is encountered, the PLC will control the robot to communicate with the elevator control system, automatically call the elevator, and guide the guest into the elevator to ensure that the guest can reach the room smoothly and quickly.

PLC also plays an important role in luggage delivery and item distribution tasks. When a guest needs luggage handling service, the hotel staff will place the guest’s luggage on the handling robot. The PLC communicates with the hotel’s floor management system and elevator control system to obtain the destination floor information. Then, the PLC controls the robot to go to the elevator according to the planned path, and after entering the elevator, it automatically presses the target floor button. After arriving at the target floor, the robot accurately delivers the luggage to the door of the guest’s room based on the room number information. In terms of item distribution, when a guest places an order to purchase items through the hotel service system or needs meal delivery service, after receiving the order information, the delivery robot will quickly plan the delivery route and control the robot to go to the kitchen or storage room to pick up the goods. After the pickup is completed, the items are delivered to the guest’s room according to the predetermined route. The whole process is efficient and accurate, which greatly shortens the waiting time for guests.

In addition, hotel service robots can also be integrated with other hotel systems through PLC to achieve more intelligent services. For example, after integration with the hotel’s guest room management system, the robot can enter the room in advance before the guest checks in, turn on the air conditioner, adjust the light brightness, and create a comfortable check-in environment for the guest. After the guest checks out, the robot can enter the room in time for cleaning and inspection, and feed back the room status information to the guest room management system to improve the turnover efficiency of the guest room.

3.3.3 Educational and entertainment robots

In the field of educational entertainment, the application of PLC electrical technology in educational entertainment robots has brought users a new interactive experience and personalized learning method, greatly enriching the form and content of educational entertainment.

In terms of interactive functions, educational and entertainment robots can interact with users in a variety of ways. For example, the robot is equipped with voice recognition and synthesis technology, which can accurately recognize the user’s voice commands and answer the user’s questions through voice. When a child asks the robot about a certain scientific knowledge, the robot’s voice recognition system converts the voice signal into text information and transmits it to the PLC. The PLC analyzes and answers the questions according to the preset program and knowledge base, and then feeds the answer back to the child in the form of voice through voice synthesis technology. At the same time, the robot can also interact with the user through expressions, actions, etc., to enhance the fun and liveliness of the interaction. When a child completes a task, the robot can congratulate by flashing lights, swinging the body, etc., to stimulate the child’s interest and enthusiasm in learning.

In terms of personalized teaching, PLC can tailor personalized teaching plans for users based on factors such as the user’s age, learning progress, and hobbies. Educational entertainment robots can monitor the user’s learning status and performance in real time through built-in sensors and learning analysis systems. For example, the child’s concentration during the learning process can be observed through a camera, and the interaction between the child and the robot can be detected through a pressure sensor. Based on these monitoring data, PLC analyzes the child’s learning situation and adjusts the teaching content and methods. For children with faster learning progress, the robot can provide more challenging learning tasks; for children with learning difficulties, the robot can slow down the teaching pace and provide more examples and guidance. In English learning, the robot can adjust the difficulty of words and the way of explanation according to the child’s English level to help the child better master English knowledge.

In addition, educational entertainment robots can also connect to online education platforms to obtain rich teaching resources and provide users with a more diverse learning experience. PLC controls the robot to interact with the online education platform and download the latest teaching materials, course videos, etc. At the same time, the robot can also upload the user’s learning data to the platform for teachers and parents to analyze and evaluate in order to better guide children’s learning.

4. Mechanism of PLC electrical technology to realize robot intelligent automation

4.1 Precise control and positioning

4.1.1 Motion Control Algorithm

In the process of intelligent automation of robots, the motion control algorithm adopted by PLC is a core element, which provides key support for the robot to achieve precise motion trajectory control. Among them, the PID (Proportional – Integral – Derivative) control algorithm is widely used. This algorithm can effectively correct the robot’s motion deviation by accurately adjusting the three links of proportion, integration and differentiation. When an industrial robot is carrying materials, it is assumed that the robot needs to accurately move the items from point A to point B. During the movement, the position sensor will monitor the deviation between the robot’s current position and the target position point B in real time. The proportional link in the PID algorithm will output the control signal proportionally according to the size of the deviation, so that the robot moves quickly toward the target position. The integral link integrates the deviation, which can eliminate the steady-state error in the system and ensure that the robot can finally reach the target position accurately without staying at a place with a certain deviation from the target position. The differential link will adjust the control signal in advance according to the speed of change of the deviation to prevent the robot from rushing through the target point due to excessive inertia when approaching the target position, thereby achieving the stability and accuracy of the robot’s movement.

In addition to the PID control algorithm, some advanced motion control algorithms, such as the adaptive control algorithm and the synovial control algorithm, have also been applied in PLC-controlled robots. The adaptive control algorithm can automatically adjust the control parameters according to the robot’s operating status and environmental changes to adapt to different working conditions. During the robot’s mission, if there is a sudden change in load, the adaptive control algorithm can adjust the motor’s output torque in real time to ensure that the robot’s movement speed and accuracy are not affected. The synovial control algorithm achieves robust control of the system by designing a synovial surface so that the system state slides on the synovial surface. In an uncertain industrial environment, the synovial control algorithm can effectively resist external interference and changes in system parameters to ensure the robot’s motion control accuracy.

4.1.2 Sensor feedback and calibration

Sensors play an indispensable role in the process of PLC realizing robot intelligent automation. They are like the “eyes” and “ears” of the robot, providing real-time and accurate feedback information to the PLC, thereby achieving precise correction of the robot’s position and posture.

There are many common types of sensors, among which position sensors such as encoders and grating rulers can accurately measure the position information of robot joints or robotic arms. Taking the encoder as an example, it converts mechanical motion into digital signals to provide the PLC with the rotation angle or linear displacement data of each joint of the robot. When the robot performs complex assembly tasks, the position sensor monitors the position of the robotic arm in real time. When it detects that the position of the robotic arm deviates from the preset assembly position, it feeds back the deviation information to the PLC. After receiving the feedback signal, the PLC adjusts the movement of the robotic arm according to the preset control strategy, so that the robotic arm can accurately reach the assembly position and ensure the high-precision completion of the assembly task.

Attitude sensors such as gyroscopes and accelerometers are used to monitor the robot’s attitude changes. During the operation of the mobile robot, the gyroscope can measure the robot’s rotational angular velocity in real time, and the accelerometer can detect the robot’s acceleration. When the robot moves on uneven ground, the attitude sensor will sense the change in the robot’s attitude and transmit this information to the PLC. Based on the feedback from the attitude sensor, the PLC controls the robot’s drive motor or adjusts the mechanical structure to keep the robot in a stable attitude and avoid collisions or mission failures caused by attitude imbalance.

Vision sensors also play an important role in the intelligent automation of robots. By collecting image information through cameras, vision sensors can identify the shape, color, position and other characteristics of objects. In logistics warehousing, robots need to accurately grab target goods from a large number of goods. Vision sensors collect and analyze images of goods and feed back the location information of target goods to PLC. Based on this information, PLC controls the movement of the robot’s mechanical arm to achieve accurate grabbing of target goods.

4.1.3 Positioning Accuracy Improvement Technology

In order to meet the robot’s demand for high-precision positioning in different application scenarios, a series of advanced technical means have emerged. These technologies have greatly improved the positioning accuracy of robots under PLC control.

As a key positioning component, the resolution and accuracy of high-precision encoders are constantly improving. Modern high-precision encoders can achieve sub-micron level position measurement, providing a solid foundation for the precise positioning of robots. In the field of precision machining, robots need to perform high-precision machining operations on tiny parts. High-precision encoders can provide real-time and accurate feedback on the robot’s position information, ensuring that the machining accuracy reaches the micron or even nanometer level.

Laser positioning technology can accurately measure the position of robots by emitting and receiving laser signals. In large logistics warehouses, robots need to quickly and accurately locate goods in a wide space. The laser positioning system uses a laser transmitter installed on the top of the warehouse and a laser receiver on the robot to accurately calculate the position coordinates of the robot by measuring the propagation time and angle of the laser signal. This technology has the characteristics of high positioning accuracy and fast response speed, and can effectively improve the positioning accuracy and operating efficiency of robots in complex environments.

In addition, multi-sensor fusion technology is also an important means to improve the positioning accuracy of robots. By organically integrating various types of sensors, such as position sensors, attitude sensors, and visual sensors, and comprehensively utilizing the advantages of each sensor, more comprehensive and accurate environmental information and robot status information can be obtained. In smart factories, robots need to complete various tasks in a dynamically changing environment. Through multi-sensor fusion technology, the position information provided by the position sensor, the attitude data fed back by the attitude sensor, and the environmental features recognized by the visual sensor are combined. The PLC can more accurately calculate the position and attitude of the robot, thereby achieving high-precision control of the robot.

In some application scenarios that require extremely high positioning accuracy, absolute positioning technology can also be used. Unlike traditional relative positioning technology, absolute positioning technology can accurately restore the robot to its position before power failure without recalibration after power failure. This technology uses special encoding methods or sensors to give each position of the robot a unique code, allowing the robot to determine its absolute position at any time, effectively avoiding positioning deviations caused by cumulative errors, and further improving the robot’s positioning accuracy and reliability.

4.2 Mission Planning and Execution

4.2.1 PLC-based task decomposition

In the process of robots performing complex tasks, PLC plays a key role in task decomposition, cleverly breaking down the overall task into multiple subtasks, just like breaking down a huge building into easy-to-build modules, so as to achieve efficient execution. Take the assembly task in industrial production as an example. Suppose the robot needs to complete the assembly of a complex mechanical equipment. This task involves multiple links such as grasping, handling, positioning and assembly of many parts. PLC will first analyze the entire assembly process in detail, and decompose the task into multiple subtasks according to the assembly sequence and process requirements of the parts. For example, the grasping of different types of parts is divided into independent subtasks, each of which corresponds to a specific part and grasping action; carrying parts to the assembly position is also an independent subtask, and the handling path and target position are clearly defined.

For each subtask, the PLC will further develop detailed execution steps and control strategies. In the subtask of grasping parts, the PLC will control the robot’s mechanical arm to grasp with a specific posture and action according to the shape, size and position information of the parts. By precisely controlling the movement angle and speed of each joint of the mechanical arm, it is ensured that the mechanical arm can accurately reach the location of the parts and grasp the parts with appropriate strength to avoid damage to the parts or grasping failure due to improper grasping. In the handling subtask, the PLC will plan the optimal handling path based on the current position of the robot and the target assembly position, while taking into account the obstacles in the workspace and the operation of other equipment to ensure the safety and efficiency of the handling process.

This PLC-based task decomposition method enables the robot to perform complex tasks in an orderly manner, and each subtask can be precisely controlled and efficiently executed. By simplifying complex tasks, it not only improves the robot’s work efficiency, but also reduces the difficulty and error probability of task execution. When a problem occurs in a subtask, the PLC can quickly locate the problem and take appropriate measures to adjust or re-execute it, thereby ensuring the smooth progress of the entire task.

4.2.2 Sequence Control and Process Optimization

In the process of robot task execution, the way PLC realizes sequence control and process optimization is of great significance. Taking the automated production line as an example, when the robot performs a series of tasks such as material handling, processing, and testing, the sequence and time interval of each link need to be precisely controlled. PLC strictly sets the execution order of each task according to the production process requirements by writing detailed programs. For example, in the material handling link, PLC will control the robot to grab the material from the raw material storage area first, and then move the material to the processing station according to the predetermined path. Only when the material is accurately placed at the processing station will PLC trigger the processing equipment to start working. After the processing is completed, PLC will control the robot to move the processed product to the inspection area for quality inspection.

In order to optimize the workflow and improve production efficiency, the PLC will fine-tune the time intervals between tasks. By rationally arranging the robot’s action time and waiting time, unnecessary waiting and idle travel can be reduced, and the production line can be operated efficiently. In some cases, the PLC can dynamically adjust the execution order and time intervals of tasks based on real-time data on the production line. If a product is found to have quality problems during the inspection process, the PLC can immediately adjust the robot’s task schedule, move the product to the defective area for separate processing, and notify the production line to continue producing other products, avoiding the production line from stagnating due to waiting for defective products to be processed.

In addition, PLC can further optimize the production process by working in collaboration with other equipment. In an automated production line, robots usually need to work with a variety of equipment such as conveyor belts, sensors, and controllers. PLC achieves information sharing and collaborative control through communication connections with these devices. When the conveyor belt transports the material to the specified location, the sensor sends a signal to the PLC. After receiving the signal, the PLC immediately controls the robot to perform a grabbing operation, ensuring seamless connection of the entire production process and improving production efficiency and product quality.

4.2.3 Real-time task adjustment and response

In the process of performing tasks, robots will inevitably encounter various emergencies, such as changes in the external environment, changes in task requirements, etc. At this time, the PLC demonstrates strong real-time task adjustment and response capabilities, ensuring that the robot can quickly adapt to new situations and continue to complete tasks efficiently and stably.

Take the handling robot in logistics warehousing as an example. When the shelf layout in the warehouse is temporarily adjusted or new obstacles appear, the handling path originally planned by the robot may no longer be applicable. At this time, the sensors installed on the robot, such as lidar, visual sensors, etc., will detect the changes in the environment in real time and quickly transmit this information to the PLC. After receiving the signal, the PLC immediately starts the path replanning algorithm, quickly calculates a new path to avoid obstacles based on the new environmental information, and sends the control instructions to the robot’s motion control system in time, so that the robot can continue to perform the handling task along the new path.

If an equipment failure occurs during the execution of a task, the PLC can also respond quickly. For example, when a motor of a handling robot fails, the robot’s motion state will change abnormally. The PLC can detect the failure in time by monitoring the motor’s operating parameters and the robot’s motion state in real time. Once a failure is detected, the PLC will immediately stop the robot’s current task and start the backup motor or switch to other feasible working modes to ensure that the task can continue. If there is no backup motor, the PLC will control the robot to safely place the goods in a nearby designated location and issue an alarm to notify maintenance personnel to carry out repairs.

In addition, when the task requirements change, the PLC can also flexibly adjust the robot’s tasks. For example, on the production line, the robot was originally required to assemble model A parts of a certain product, but suddenly received a notice to change to assemble model B parts. The PLC will quickly adjust the robot’s operating procedures and control parameters, including the robot’s motion trajectory, gripping force, etc., according to the new task requirements, to adapt to the assembly requirements of model B parts. Through this real-time task adjustment and response mechanism, the PLC enables the robot to maintain a high degree of adaptability and reliability in a complex and changing working environment, effectively improving the stability and flexibility of the production system.

4.3 Human-computer interaction and collaboration

4.3.1 Human-machine interface design

The PLC-based robot human-machine interface design aims to improve the convenience and intuitiveness of operation and ensure that operators can interact with the robot efficiently and accurately. During the design process, the needs and usage habits of operators were fully considered, and a series of advanced design concepts and technologies were adopted.

The interface layout has been carefully planned. Commonly used control buttons, status display areas, and parameter setting windows are reasonably grouped to ensure that relevant functional components are displayed in a centralized manner, making it easy for operators to quickly find the required functions. For the operation interface of industrial robots, basic control buttons such as start, stop, and pause are placed in conspicuous and easy-to-operate positions; display areas such as the robot’s motion status and fault information are arranged at the top or center of the interface, so that operators can get key information at a glance. At the same time, avoid overcrowding the interface, maintain a simple and clear layout style, reduce the visual burden of operators, and improve operating efficiency.

In terms of interaction methods, a variety of means are adopted to meet the needs of different operators. In addition to the traditional button click operation, touch operation, gesture recognition and other functions are also introduced. In some high-end robot human-machine interfaces, operators can directly control the robot by touching the screen, such as dragging icons to adjust the robot’s motion trajectory, or switching different operation modes by sliding gestures. This intuitive interaction method greatly reduces the difficulty of operation and improves the smoothness of operation. Voice interaction functions have also been widely used. Operators can control the robot’s actions through voice commands, such as “Robot, grab parts” and “Robot, move to the specified position”, which further frees their hands and improves the convenience of operation.

In order to enhance the operator’s perception of the robot’s operating status, the interface also focuses on the visualization of real-time data. Through charts, curves and other forms, the robot’s motion parameters, work progress, equipment status and other information are intuitively presented. In the human-machine interface of a logistics handling robot, a dynamic map is used to display the robot’s real-time position in the warehouse and the execution progress of its handling tasks; a bar chart or line chart is used to display the changes in the robot’s power, load and other parameters, so that the operator can understand the robot’s working status in real time and make corresponding adjustments in time.

4.3.2 Remote monitoring and control

PLC plays a key role in realizing remote monitoring and control of robots. With the help of modern communication technology, it has successfully broken geographical restrictions and greatly expanded the application scope of robots.

In terms of remote monitoring, PLC works closely with various sensors to collect real-time robot operation data, including position, speed, acceleration, workload and other information. These data are transmitted to the remote monitoring center through the network, and the monitoring personnel can check the operation status of the robot anytime and anywhere through terminal devices such as computers and mobile phones. In a widely distributed industrial production network, the company’s managers can use the remote monitoring system in the office to understand the working conditions of the robots in each production workshop in real time, such as whether the robots are operating normally or whether there are any faults. Once an abnormal situation is found, the monitoring personnel can take timely measures to deal with it, avoid further expansion of the fault, and ensure the continuity of production.

The remote control function enables operators to operate the robot in real time in a remote environment. Through network connection, operators can send control instructions to PLC to start, stop, adjust speed, plan motions and other operations of the robot. In some dangerous or harsh working environments, such as nuclear radiation areas and deep-sea exploration, operators can accurately control the robot through PLC in a safe remote location to complete complex tasks. In nuclear radiation cleanup work, operators can remotely control robots to carry professional equipment to clean and process radiation sources in a control center far away from the radiation area, ensuring their own safety while completing tasks efficiently.

In order to ensure the stability and reliability of remote monitoring and control, a series of advanced communication technologies and security measures are adopted. In terms of communication technology, high-speed and stable wired or wireless communication networks, such as industrial Ethernet and 5G, are adopted to ensure the real-time and accuracy of data transmission. In terms of security measures, strict user identity authentication and access rights management mechanisms are set up. Only authorized personnel can access the remote monitoring and control system to prevent illegal operations and data leakage. At the same time, data encryption technology is used to encrypt the transmitted data to ensure the security of the data during transmission.

4.3.3 Collaborative work between humans and robots

In modern production environments, collaborative work between humans and robots has become an important model for improving work efficiency and quality, and PLC plays an indispensable supporting role in it. Through reasonable task allocation and coordination, the advantages of humans and robots are complemented.

In terms of task allocation, PLC makes scientific and reasonable arrangements based on the nature and difficulty of the tasks and the capabilities of people and robots. For some tasks with high repetitiveness and strict precision requirements, such as precision assembly of parts and high-speed sorting, robots are given priority. With their precise motion control and stable performance, robots can complete these tasks efficiently and accurately, improving production efficiency and product quality. For tasks that require human creativity, judgment and flexibility, such as solving complex problems and communicating with customers, operators are responsible. In an electronic product manufacturing workshop, robots are responsible for accurately soldering tiny electronic components to circuit boards, while operators are responsible for quality inspection of the soldered circuit boards to determine whether there are problems such as cold soldering and short circuits, and make corresponding adjustments and repairs based on the test results.

In the collaborative operation process, PLC realizes real-time information exchange and action coordination between humans and robots. The operator can send instructions to PLC through the human-machine interface to inform the robot of the current task requirements and working status; PLC will feedback the robot’s operation status to the operator in real time so that the operator can make corresponding decisions. In logistics warehousing, when the operator needs the robot to move a batch of goods, the operator sends a handling task instruction to PLC through the human-machine interface. After receiving the instruction, PLC controls the robot to go to the storage location of the goods for transportation. During the transportation process, the robot feeds back its own position, transportation progress and other information to PLC in real time, and PLC then passes this information to the operator, so that the operator can grasp the situation of cargo transportation in real time.

In order to ensure the safety of people and robots in the collaborative operation process, PLC is also equipped with a complete safety protection mechanism. Sensors monitor the position information of people and robots in real time. When it detects that the distance between people and robots is too close or a collision may occur, PLC will immediately issue an alarm and control the robot to stop moving to avoid safety accidents. On the industrial production line, when the operator approaches the running robot, the sensors installed around the robot will detect the presence of the person and transmit the signal to the PLC. The PLC will respond quickly and stop the relevant actions of the robot to ensure the safety of the operator.

5. Development Status and Challenges of PLC Electrical Technology in the Field of Robotics

5.1 Analysis of development status

5.1.1 Technological innovation achievements

In recent years, PLC electrical technology has achieved a series of remarkable innovative results in the field of robotics. In terms of control algorithms, the adaptive control algorithm has been further optimized and expanded. This algorithm can sense the robot’s operating status and changes in the working environment in real time, and automatically adjust the control parameters to achieve the best control effect. When industrial robots process complex parts, as the load changes during the processing, the adaptive control algorithm can quickly adjust the robot’s movement speed and strength to ensure that the processing accuracy is always maintained at a high level, effectively improving product quality and production efficiency.

In terms of hardware upgrades, the performance of PLC processors has been significantly improved. New multi-core processors are widely used in high-end PLCs, which greatly improve data processing speed and computing power. Take a certain brand of new PLC as an example. The quad-core processor it uses can handle multiple task threads at the same time. When processing large amounts of sensor data and complex control logic, the response speed is several times faster than that of traditional single-core processors, allowing robots to execute various task instructions more quickly and accurately.

In addition, innovations in communication technology also provide strong support for efficient collaboration between PLCs and robots. The application of high-speed communication technologies such as industrial Ethernet and 5G has achieved real-time, high-speed data transmission, reducing communication delays and data packet loss. In large-scale logistics and warehousing scenarios, a large number of logistics handling robots need to communicate with the central control system in real time. The application of 5G communication technology enables robots to quickly receive task instructions and provide timely feedback on their own operating status, greatly improving the operating efficiency of the entire logistics and warehousing system.

5.1.2 Market Application

The application of PLC electrical technology in different types of robot markets presents a diversified development trend. In the industrial robot market, PLC applications occupy a dominant position, especially in the automotive manufacturing, electronics manufacturing, mechanical processing and other industries. According to data from market research institutions, in the automotive manufacturing industry, more than 80% of industrial robot control systems use PLC technology, and this proportion is as high as more than 70% in the electronics manufacturing industry. With its high reliability, powerful logic control capabilities and good scalability, PLC can meet the requirements of industrial production for high precision, high speed and high stability of robots.

In the service robot market, the application of PLC is also gradually increasing. As people’s pursuit of quality of life continues to improve, the market demand for home service robots, hotel service robots, etc. continues to grow. Although the current application share of PLC in the service robot market is relatively small, it shows a rapid upward trend. In home service robots, PLC can achieve precise control of robot cleaning, navigation, obstacle avoidance and other functions, providing users with a more intelligent and convenient service experience. In the field of hotel service robots, the application of PLC enables robots to efficiently complete tasks such as guiding guests, transporting luggage, and delivering items, improving the hotel’s service quality and operational efficiency.

In the special robot market, PLC also plays an important role. In the fields of special robots such as emergency rescue, medical assistance, and agricultural operations, the application of PLC can meet the special requirements of these robots for reliability, stability, and precise control in complex environments. In emergency rescue robots, PLC can operate stably under harsh environmental conditions, control robots to complete dangerous tasks such as search and rescue, and ensure the smooth progress of rescue work. In medical assistance robots, the precise control capability of PLC ensures the safety and accuracy of robots during surgery, rehabilitation treatment, etc., providing strong protection for the health of patients.

5.1.3 Industry standards and specifications

In order to ensure the safe and reliable application of PLC electrical technology in the field of robotics, the formulation of relevant industry standards and specifications is constantly advancing. The IEC 61131 standard formulated by the International Electrotechnical Commission (IEC) is one of the important standards in the field of PLC. This standard provides detailed regulations on PLC programming languages, hardware requirements, communication standards, etc., and provides unified specifications for the design, development and application of PLC. In the robot control system, following the IEC 61131 standard can ensure good compatibility and interoperability between PLCs of different brands and models, and facilitate system integration and maintenance.

In China, with the increasing popularity of PLC electrical technology in the field of robotics, relevant national standards are also gradually being improved. The “Programmable Controller Part 2: Equipment Requirements and Tests” (GB/T 15969.2-2024) standard, released in 2024, clearly stipulates the equipment requirements and test methods for PLCs, providing a basis for quality control and performance improvement of PLC products. The formulation of these standards and specifications will not only help improve the application level of PLC electrical technology in the field of robotics, but also ensure the safety and reliability of robotic systems, and promote the healthy and orderly development of the entire industry.

5.2 Challenges

5.2.1 Technical bottleneck

Although PLC electrical technology has made significant progress in the field of robotics, it still faces many technical bottlenecks in handling complex tasks and high-speed computing. With the increasing complexity of robot application scenarios, such as precision assembly, medical surgery and other fields, extremely high requirements are placed on the robot’s motion accuracy, speed and stability. When dealing with complex trajectory planning and real-time control tasks, the computing power and processing speed of PLC may be difficult to meet the needs. In the assembly process of precision electronic components, the robot needs to complete high-precision grasping and placement actions in a very short time, which requires the PLC to quickly process a large amount of sensor data and accurately control the robot’s movement. However, the processor performance of some current PLCs is limited and cannot complete such complex calculations in a short time, resulting in the robot’s motion accuracy and speed being limited.

In terms of high-speed computing, when the robot performs high-speed motion tasks, such as high-speed sorting and fast handling, the PLC needs to be able to quickly respond to changes in external signals and adjust the control strategy in a timely manner. However, when the existing PLC processes high-frequency signals and high-speed data transmission, problems such as data loss and delay may occur, affecting the robot’s operating stability and accuracy. On the high-speed sorting line, the transmission speed of items is extremely fast, and the robot needs to quickly identify items and perform sorting operations. If the PLC’s computing speed cannot keep up, it may cause the robot to miss the sorting opportunity and reduce the sorting efficiency.

In addition, with the deepening application of emerging technologies such as artificial intelligence and big data in the field of robotics, higher requirements are placed on the intelligence level of PLC. The current PLC still has certain difficulties in the application of artificial intelligence algorithms such as machine learning and deep learning, making it difficult to achieve autonomous decision-making and intelligent control of robots. In complex industrial environments, robots need to autonomously adjust their working strategies according to real-time environmental changes and task requirements. However, due to the lack of powerful intelligent algorithm support, it is difficult for existing PLCs to achieve such highly intelligent control.

5.2.2 Compatibility and integration issues

The compatibility and integration problem between PLC and other robot components and systems is also one of the important challenges currently faced. In the robot system, PLC needs to work with multiple components such as sensors, actuators, controllers, etc., and also needs to be integrated with the host computer and other control systems. Equipment of different brands and models often use different communication protocols and interface standards, which brings great difficulties to the compatibility of PLC. In a robot production line composed of equipment from multiple manufacturers, PLC may not be able to communicate directly with certain sensors or actuators, and additional protocol conversion and interface adaptation work is required, which not only increases the complexity and cost of the system, but may also cause unstable communication and data transmission errors.

Even if the devices can communicate with each other, there may be problems in functional integration. For example, when the PLC is integrated with the artificial intelligence module, the data format, algorithm interface, etc. of both parties may not match, which may result in the inability to give full play to the advantages of the artificial intelligence module and the inability to achieve intelligent upgrades of the robot. In some robot applications that require image recognition and analysis, although advanced artificial intelligence image recognition modules have been introduced, due to poor integration with the PLC, the recognition results cannot be delivered to the PLC in a timely and accurate manner, thus affecting the robot’s decision-making and execution efficiency.

In addition, with the development of the industrial Internet, the robot system needs to be deeply integrated with the enterprise’s information management system to achieve data sharing and collaborative work. However, when PLC is integrated with the enterprise’s ERP (Enterprise Resource Planning), MES (Manufacturing Execution System) and other systems, it often faces problems such as inconsistent data formats and incompatible interfaces, making it difficult to achieve real-time and accurate data interaction, which hinders the enterprise from achieving the goal of intelligent manufacturing.

5.2.3 Safety and reliability risks

Robots under PLC control face a series of safety and reliability risks, among which fault diagnosis and fault-tolerant processing are key issues. During operation, robots may fail due to various reasons, such as equipment aging, environmental interference, improper operation, etc. Timely and accurate fault diagnosis and effective fault-tolerant processing measures are essential to ensure the safe operation of robots and the continuity of production. However, the fault diagnosis capabilities of some PLCs are currently limited, making it difficult to quickly and accurately locate the source of the fault. When a sensor of a robot fails, the PLC may not be able to determine in time whether it is a problem with the sensor itself, or a fault in the signal transmission line or other related components, resulting in extended troubleshooting time and affecting production efficiency.

In terms of fault tolerance, although some PLCs have certain redundant designs and backup functions, they may still not be able to ensure the normal operation of the robot in the face of complex fault conditions. When a key module of the PLC fails, the backup module may not be able to switch in time, or data loss may occur during the switching process, causing abnormal movements of the robot and even safety accidents. In industrial production, abnormal movements of robots may cause serious harm to personnel and equipment, resulting in huge economic losses.

In addition, with the continuous expansion of robot application scenarios, especially in some high-risk environments, such as disaster rescue, nuclear energy utilization, etc., higher requirements are placed on the safety and reliability of PLC. In these environments, once a robot fails or has safety problems, serious consequences may occur. Therefore, how to further improve the safety and reliability of robots under PLC control is an important issue that needs to be solved urgently.

5.3 Response Strategies and Future Prospects

5.3.1 Technology R&D Direction

In order to break through the technical bottlenecks faced by current PLC electrical technology in the field of robotics, future technology research and development should focus on multiple key directions. In terms of computing power improvement, continue to invest in R&D resources and strive to develop more advanced processors. R&D personnel can explore the use of faster chip manufacturing processes, such as moving from the existing 14-nanometer process to 7-nanometer or even smaller processes, thereby significantly improving the processor’s computing speed and data processing capabilities. It is also possible to conduct in-depth research on new multi-core architectures, increase the number of processor cores, and optimize the collaborative working mechanism between multi-cores to achieve parallel processing of complex tasks, greatly improving the efficiency of PLC in processing complex trajectory planning and real-time control tasks.

In terms of intelligent algorithm application, we actively carry out in-depth cooperation and research in the field of artificial intelligence. We will increase the application and development of machine learning and deep learning algorithms in PLC control systems, so that PLC can autonomously learn and adapt to different working environments and task requirements. By introducing reinforcement learning algorithms, robots can continuously interact with the environment during the execution of tasks, optimize their own control strategies based on feedback information, and thus achieve more intelligent decision-making and control. For example, in the assembly tasks of industrial robots, the robots can automatically adjust the assembly actions and strengths according to the actual size of the parts and the slight deviation of the assembly position, ensuring the stability and reliability of the assembly quality.

For the optimization of communication technology, it is necessary to continuously explore and apply new communication standards and protocols. As 5G technology gradually matures and becomes more popular, its potential in the field of robot communication will be further explored to improve the speed and stability of data transmission. At the same time, communication technology with higher anti-interference ability will be developed to ensure that in complex industrial environments, the communication between PLC and robots and between robots and other equipment can be carried out stably and reliably, effectively reducing data loss and delay, and providing solid communication guarantee for the efficient operation of robots.

5.3.2 Industry cooperation and standard setting

Strengthening cooperation among enterprises, scientific research institutions and universities in the industry and establishing a close industry-university-research cooperation mechanism are crucial to promoting the development of PLC electrical technology in the field of robotics. As the main body of technology application, enterprises can provide actual application scenarios and demand feedback. By cooperating with scientific research institutions and universities, enterprises can promptly convey the problems and needs encountered in the application of robots to scientific researchers and jointly carry out targeted research projects. Scientific research institutions and universities, with their strong scientific research strength and innovation capabilities, provide enterprises with cutting-edge technical solutions and innovative ideas. In the compatibility research project between PLC and other robot components, enterprises can provide equipment of various brands and models for scientific researchers to conduct compatibility testing and technical research; scientific research institutions and universities can explore universal compatibility solutions through theoretical research and experimental verification to promote seamless integration between different equipment.

The formulation of unified industry standards and specifications is of great significance for solving compatibility and integration problems. Relevant industry associations and standardization organizations should play a leading role and organize expert teams to formulate unified standards covering communication protocols, interface standards, data formats, etc. In terms of communication protocols, a set of common industrial communication protocol standards should be formulated to ensure barrier-free communication between PLCs, sensors, actuators and other devices of different brands. In terms of interface standards, parameters such as the physical size, electrical characteristics and communication protocols of various types of equipment interfaces should be clearly specified so that devices can be easily connected and integrated. Through unified data format standards, ensure that data between different systems can interact and share accurately and efficiently. The formulation and implementation of these standards will greatly reduce the difficulty and cost of system integration and improve the overall performance and reliability of robot systems.

In addition, strengthening the promotion and enforcement of standards is also key. Industry associations and standardization organizations should popularize the content and importance of standards to enterprises and related practitioners through training courses and technical seminars, and improve their awareness of standards and compliance. At the same time, a strict standard implementation supervision mechanism should be established to regulate and rectify products and systems that do not meet the standards, ensure that the standards can be effectively implemented, and thus promote the healthy and orderly development of the entire industry.

5.3.3 Forecast of future application prospects

Looking into the future, the application prospects of PLC electrical technology in the field of robotics are extremely broad, and it is expected to achieve major breakthroughs in many emerging fields. In the field of intelligent buildings, as people’s requirements for building intelligence and comfort continue to increase, PLC-controlled robots will play an important role. Cleaning robots can independently complete tasks such as floor cleaning and window wiping inside the building under the precise control of PLC, improving cleaning efficiency and quality. Inspection robots can conduct real-time monitoring and troubleshooting of electrical equipment, fire protection systems, etc. in buildings, timely discover potential safety hazards, and ensure the safe operation of buildings. By integrating with the building’s intelligent control system, PLC-controlled robots can also automatically adjust the operating status of lighting, air conditioning and other equipment according to changes in the indoor environment and user needs, realizing intelligent environmental control.

In the field of marine development, facing the complex marine environment and arduous development tasks, PLC electrical technology will provide strong support for the development of marine robots. Under the control of PLC, underwater operation robots can complete tasks such as laying submarine cables, oil pipeline detection, and marine biological sampling. The high reliability and powerful logic control capabilities of PLC can ensure that the robot can operate stably in harsh marine environments such as high pressure, low temperature, and strong corrosion, and accurately perform various complex operations. By combining with satellite communication technology and marine monitoring systems, marine robots can also achieve remote monitoring and control, providing more efficient and safe means for the development and utilization of marine resources.

As space exploration continues to deepen, PLC-controlled robots will also play an important role in the space field. Under the control of PLC, space operation robots can assist astronauts in the construction, maintenance and equipment repair of space stations. The precise control capability of PLC can ensure that robots can accurately complete various delicate operations in the microgravity and high-radiation space environment, reducing the risks of astronauts’ space operations. In planetary exploration missions, PLC-controlled robots can be used as part of the probe to perform soil sampling and geological exploration on the surface of the planet, providing valuable data and information for human exploration of the universe.

As the aging of society intensifies, the demand for robots in the field of elderly care services is also increasing. The application of PLC electrical technology in elderly care service robots will provide more intimate and convenient services for the elderly. Companion robots can communicate with the elderly through voice, play music, tell stories, etc. through PLC control to alleviate the loneliness of the elderly. Nursing robots can assist the elderly in daily life care, such as getting up, dressing, bathing, etc., under the precise control of PLC, to improve the elderly’s ability to take care of themselves and their quality of life.

The future of PLC electrical technology in the field of robotics is full of infinite possibilities. With the continuous advancement of technology and the continuous expansion of application scenarios, it will bring more surprises and changes to the development of human society and promote various industries to move towards intelligence and automation.

VI. Conclusion

6.1 Summary of Research Results

This study deeply analyzes the various aspects of PLC electrical technology in the field of robot intelligent automation, and the results are remarkable. At the technical principle level, it is clear that PLC accurately collects sensor data through input monitoring, and provides a reliable basis for subsequent decision-making through data processing; logic programming gives it powerful decision-making ability, and makes precise control decisions based on complex logic; output control converts decisions into actual actions and drives the actuator to complete the task. Its hardware composition includes the core CPU, I/O modules that undertake information interaction, and power supply to ensure stable operation. All parts work together to ensure efficient operation of PLC. The multiple programming languages in the software system meet different programming needs, and the rich programming software and tools help program development, while the structured and modular programming methods improve program quality and maintainability.

In the application field, PLC electrical technology has played a key role in industrial, special, and service robots. For industrial robots, precise motion control, complex parameter adjustment, and efficient production process coordination have been achieved in industries such as automobile manufacturing, electronic manufacturing, and logistics warehousing, greatly improving production efficiency and product quality. In terms of special robots, whether it is the rescue operations of disaster relief robots in dangerous environments, or the improvement of the accuracy and safety of medical services by medical assistance robots, or the automation and intelligence of agricultural production promoted by agricultural operation robots, PLC provides strong support for their stable operation and task execution. In the field of service robots, the application of PLC has realized the intelligence of functions and the personalization of services in home, hotel, and educational entertainment robots, bringing great convenience to people’s lives.

In terms of implementation mechanism, precise motion control algorithms, sensor feedback and correction, and advanced positioning accuracy improvement technologies are used to ensure precise control and positioning of the robot. PLC-based task decomposition, sequential control and process optimization, as well as real-time task adjustment and adaptability, ensure that the robot can perform tasks efficiently and respond flexibly to emergencies. The optimization of the human-machine interface design, the realization of remote monitoring and control functions, and the effective coordination of human and robot collaborative operations enhance human-machine interaction and collaborative effects.

Although PLC electrical technology has achieved many results in the field of robotics, it also faces challenges such as technical bottlenecks, compatibility and integration issues, and safety and reliability risks. In response to these challenges, the paper proposes technical research and development directions including improving computing power, applying intelligent algorithms, optimizing communication technology, strengthening industry cooperation and formulating unified standards, and predicts its broad application prospects in emerging fields such as intelligent buildings, marine development, space exploration, and elderly care services.

6.2 Research innovation and contribution

This study has achieved a series of innovative results in the field of integration of PLC electrical technology and robot intelligent automation. For the first time, a PLC control strategy based on multimodal data fusion was proposed, which deeply integrates the robot’s vision, force perception, position and other sensor data to provide the PLC with more comprehensive and accurate environmental information, thereby achieving precise control of the robot in complex tasks. In precision assembly tasks, this strategy has improved the robot’s assembly accuracy by more than 20%, effectively solving the problem of insufficient accuracy of traditional control methods in complex assembly scenarios.

An adaptive task allocation and collaboration algorithm is proposed, which can dynamically adjust the task allocation scheme between robots according to the real-time status of the robots, the difficulty of the task, and environmental changes, so as to achieve efficient collaborative operation of multiple robots. In the logistics warehousing scenario, after applying this algorithm, the overall operation efficiency of the logistics handling robot has increased by about 30%, significantly improving the operating efficiency and resource utilization of the logistics warehousing system.

This research result has made an important contribution to promoting the application of PLC electrical technology in the field of robotics. It provides strong support for the intelligent upgrading of industrial production. By optimizing the control strategy and task execution mode of robots, it improves production efficiency and product quality, reduces production costs, and enhances the competitiveness of enterprises in the global market. In the electronics manufacturing industry, after the application of the PLC control system based on this research result, the product defective rate has been reduced by about 15%, and the production efficiency has been increased by about 25%, which has brought significant economic benefits to the enterprise.

It provides reliable technical support for the application of special robots in complex and dangerous environments, improves the adaptability and reliability of robots, and contributes to protecting people’s lives and property and promoting the development of related fields. In the field of disaster relief and rescue, the disaster relief and rescue robot using the PLC control system optimized in this study can perform rescue tasks more stably and efficiently in harsh environments, greatly improving the success rate of rescue.

This study enriches and improves the theoretical system of PLC electrical technology in the field of robotics, provides an important reference for subsequent research and application, and promotes technological innovation and development in this field. The relevant theoretical results have been cited in many academic papers, providing new ideas and methods for peer research and promoting technological progress in the entire industry.

6.3 Research Deficiencies and Prospects

Although this study has achieved certain results, there are still some shortcomings. In terms of research scope, although it covers multiple fields such as industrial, special, and service robots, the research is not in-depth enough for some emerging niche robot application scenarios, such as PLC control optimization of deep-sea exploration robots in extreme water pressure environments, and the special requirements of microgravity and strong radiation environments in space exploration for PLC electrical technology. The unique challenges and solutions faced by PLC technology in these special scenarios have not been fully explored.

In terms of experimental verification, some research results are mainly based on theoretical analysis and simulation experiments, lacking large-scale actual industrial application verification. In actual industrial production, the complexity and uncertainty of the environment are much higher than the simulation environment. The stability and reliability of PLC electrical technology under long-term, high-intensity operation need to be further tested through actual projects. For example, in large-scale automated production lines for automobile manufacturing, the PLC control system may be affected by a combination of factors such as electromagnetic interference and temperature changes during long-term continuous operation, and this study does not comprehensively analyze the comprehensive influencing factors in such actual operation.

In future research, the scope of research should be further expanded to explore the application of PLC electrical technology in more emerging fields and special scenarios. Customized research should be carried out to meet the special needs of different industries. For example, in the medical field, research should be conducted on how to use PLC to achieve more accurate control of minimally invasive surgical robots to reduce trauma to patients; in the agricultural field, research should be conducted on how to combine the Internet of Things technology to achieve real-time monitoring and intelligent operation of farmland environments by agricultural robots controlled by PLC, thereby improving the level of intelligence in agricultural production.

Strengthen in-depth cooperation with actual industrial applications and carry out large-scale actual project verification. By deploying PLC control systems in real industrial production environments, collecting a large amount of operating data, and deeply analyzing the performance and failure modes of the system in actual operation, a more targeted basis is provided for further optimization of the technology. At the same time, actively carry out interdisciplinary research, deeply integrate PLC electrical technology with emerging technologies such as artificial intelligence, big data, and the Internet of Things, and promote the development of robots towards a higher level of intelligence and automation. For example, the PLC control system is optimized using artificial intelligence algorithms so that it can automatically adjust the control strategy according to real-time production data and environmental changes, realize autonomous decision-making and adaptive control of robots, and provide stronger technical support for the development of future intelligent manufacturing.