my country's industrial robot market is mainly concentrated in the automotive, auto parts, motorcycle, electrical appliance, construction machinery, and petrochemical industries. As the third largest consumer of industrial robots in Asia, China's market is developing steadily. Automotive and auto parts manufacturing remains the primary application area for industrial robots. With the deepening of my country's industrial restructuring and upgrading, and the shift of international manufacturing centers to my country, the Chinese robot market will further expand, and the pace of market expansion will also increase. This article reviews the key technologies and applications of industrial robots.
The robot control system is the brain of the robot, and it is the main factor determining the robot's functions and performance. The main task of industrial robot control technology is to control the robot's position, posture, trajectory, operation sequence, and the timing of actions within the workspace. It features simple programming, software menu operation, a user-friendly human-machine interface, online operation prompts, and ease of use.
Key technologies include:
(1) Open and modular control system architecture: It adopts a distributed CPU computer structure, which is divided into robot controller (RC), motion controller (MC), opto-isolated I/O control board, sensor processing board and programming teach pendant, etc. The robot controller (RC) and programming teach pendant communicate through serial port/CAN bus. The main computer of robot controller (RC) completes the robot's motion planning, interpolation and position servo, as well as main control logic, digital I/O, sensor processing and other functions, while the programming teach pendant completes the display of information and key input.
(2) Modular and Hierarchical Controller Software System: The software system is built on the open-source real-time multitasking operating system Linux, and adopts a layered and modular structure design to achieve the openness of the software system. The entire controller software system is divided into three layers: hardware driver layer, core layer, and application layer. The three layers address different functional requirements and correspond to different levels of development. Each layer in the system consists of several functionally opposing modules, which cooperate with each other to achieve the functions provided by that layer.
(3) Robot fault diagnosis and safety maintenance technology: Diagnosing robot faults and carrying out corresponding maintenance through various information is a key technology to ensure robot safety.
(4) Networked robot controller technology: Currently, robot applications are evolving from single robot workstations to robot production lines, making the networking technology of robot controllers increasingly important. The controller has serial ports, fieldbus, and Ethernet networking capabilities. This allows for communication between robot controllers and between the robot controller and a host computer, facilitating the monitoring, diagnosis, and management of the robot production line.
Automated Guided Vehicles (AGVs)
Automated Guided Vehicles (AGVs) are a type of industrial robot. They are computer-controlled and have functions such as movement, automatic navigation, multi-sensor control, and network interaction. They can be widely used in industries such as machinery, electronics, textiles, tobacco, medical, food, and papermaking for flexible handling and transmission. They are also used in automated warehouses, flexible processing systems, and flexible assembly systems (using AGVs as mobile assembly platforms). At the same time, they can be used as transportation tools in the sorting of goods at stations, airports, and post offices.
One of the new trends in international logistics technology development is mobile robots, which are a core technology and equipment. They are high-tech equipment that use modern logistics technology to cooperate with, support, transform and upgrade traditional production lines, and achieve point-to-point automatic storage and retrieval of high-bay container storage, operation and handling. This enables precision, flexibility and informatization, shortens the logistics process in Ningbo, reduces material loss, reduces land area, and reduces construction investment.
Spot welding robot
Welding robots are characterized by stable performance, large working space, high movement speed and strong load capacity. Their welding quality is significantly better than that of manual welding, greatly improving the productivity of spot welding operations.
Spot welding robots are mainly used for welding work on automobiles, a process handled by major automakers. International industrial robot companies, leveraging their long-term partnerships with major automakers, supply various spot welding robot units to these large manufacturers and enter the Chinese market by integrating welding robots with vehicle production lines, thus achieving a dominant market position in this field.
With the development of the automotive industry, welding production lines require integrated welding guns, resulting in increasingly heavier robots. The 165kg spot welding robot is currently one of the most commonly used robots in automotive welding. In September 2008, the Robotics Research Institute completed the development of China's first 165kg-class spot welding robot, which was successfully applied in Chery Automobile's welding workshop. In September 2009, the second robot, after optimization and performance improvements, was completed and successfully passed acceptance testing. The overall technical specifications of this robot have reached the level of similar robots abroad.
Arc welding robot
Arc welding robots are primarily used in the welding production of various automotive parts. In this field, large international industrial robot manufacturers mainly supply unit products to complete equipment suppliers. Our company primarily manufactures complete arc welding robot systems. Depending on the specific needs of various projects, we manufacture the robot unit products within these systems ourselves, or we purchase and assemble various arc welding robot systems from large industrial robot companies. In this field, our company has both competitive and cooperative relationships with large international industrial robot manufacturers.
Key technologies include:
(1) Arc welding robot system optimization and integration technology: The arc welding robot adopts AC servo drive technology and high-precision, high-rigidity RV reducer and harmonic reducer, which has good low-speed stability and high-speed dynamic response, and can achieve maintenance-free function.
(2) Coordinated control technology: Controlling the coordinated movement of multiple robots and positioners can maintain the relative posture of the welding torch and the workpiece to meet the requirements of the welding process, and avoid collision between the welding torch and the workpiece.
(3) Precise weld seam trajectory tracking technology: Combining the advantages of laser sensor and vision sensor offline working mode, laser sensor is used to realize weld seam tracking in the welding process, which improves the flexibility and adaptability of welding robot to weld complex workpieces. The residual deviation of weld seam tracking is obtained by offline observation of vision sensor. Based on the deviation statistics, compensation data is obtained and the robot motion trajectory is corrected, so that the best welding quality can be obtained under various working conditions.
Laser processing robot
Laser processing robots apply robotics technology to laser processing, enabling more flexible laser processing operations through high-precision industrial robots. This system operates online via a teach pendant and can also be programmed offline. The system automatically detects the workpiece, generates a model of it, and then produces processing curves. It can also directly process data using CAD data. Applications include laser surface treatment, drilling, welding, and mold repair.
Key technologies include:
(1) Laser processing robot structure optimization design technology: adopt a large-scale frame-type body structure to increase the working range while ensuring the robot's accuracy;
(2) Error compensation technology for robot system: In view of the requirements of large working space and high precision of integrated processing robot, and combined with its structural characteristics, a hybrid robot compensation method combining non-model method and model-based method was adopted to complete the compensation of geometric parameter error and non-geometric parameter error.
(3) High-precision robot inspection technology: By combining coordinate measuring technology and robot technology, high-precision online measurement of robots is realized.
(4) Laser processing robot special language implementation technology: Based on the characteristics of laser processing and robot operation, complete the laser processing robot special language.
(5) Network communication and offline programming technology: It has network communication functions such as serial port and CAN to realize the monitoring and management of robot production line; and realizes the offline programming control of robot by host computer.
vacuum robot
Vacuum robots are robots that operate in a vacuum environment, primarily used in the semiconductor industry to transfer wafers within vacuum chambers. Vacuum robotic arms are difficult to import, subject to restrictions, used in large quantities, and highly versatile, making them a key component restricting the development progress and competitiveness of complete semiconductor equipment. Furthermore, foreign buyers subject Chinese buyers to stringent scrutiny, and vacuum robotic arms are included in embargo lists, making them a serious bottleneck hindering the manufacturing of complete semiconductor equipment in my country. Direct-drive vacuum robot technology is an original innovative technology.
Key technologies include:
(1) New configuration design technology for vacuum robots: By structural analysis and optimization design, international patents are avoided, and new configurations are designed to meet the requirements of vacuum robots for stiffness and extension ratio;
(2) Large gap vacuum direct drive motor technology: This involves the theoretical analysis, structural design, manufacturing process, surface treatment of motor materials, low speed and high torque control, and small multi-axis drive of large gap vacuum direct drive motors and high cleanliness direct drive motors.
(3) Design of multi-axis precision shaft system in vacuum environment. The design method of shaft in shaft is adopted to reduce the problems of misalignment and inertia asymmetry between shafts.
(4) Dynamic trajectory correction technology: By fusing sensor information and robot motion information, the offset between the reference position of the wafer and the finger is detected. By dynamically correcting the motion trajectory, the robot can accurately transfer the wafer from one station in the vacuum chamber to another station.
(5) Vacuum robot language conforming to SEMI standards: Based on the vacuum robot handling requirements, robot operation characteristics and SEMI standards, complete the vacuum robot-specific language.
(6) Reliability Systems Engineering Technology: In IC manufacturing, equipment failures can lead to huge losses. Based on the high requirements of semiconductor equipment for MCBF, the reliability of each component is tested, evaluated and controlled to improve the reliability of each component of the robot, thereby ensuring that the robot meets the high requirements of IC manufacturing.
Cleanroom robots
Cleanroom robots are industrial robots used in clean environments. As production technology continues to improve, the requirements for the production environment are becoming increasingly stringent. Many modern industrial products require clean environments for production, and cleanroom robots are key equipment needed for production in clean environments.
Key technologies include:
(1) Clean lubrication technology: By adopting a negative pressure dust suppression structure and non-volatile grease, the environment is free from particulate pollution and the cleanliness requirements are met.
(2) High-speed and stable control technology: By optimizing the trajectory and improving the joint servo performance, the stability of clean handling is achieved.
(3) Miniaturization technology of controller: Due to the high construction and operation costs of cleanrooms, the space occupied by cleanroom robots is reduced through controller miniaturization technology.
(4) Wafer inspection technology: Through optical sensors, information such as whether there are missing wafers or tilting in the cassette can be obtained by scanning with a robot.
Analysis of commonly used precision reducer technology in industrial robots
An industrial robot is a general-purpose machine equipped with memory devices and end effectors, capable of performing various movements or processes to replace human labor. In production, it typically replaces workers in performing monotonous, frequent, and repetitive long-term tasks, or in hazardous or harsh environments. It can improve production efficiency and product quality, and is an effective solution for enterprises to supplement and replace their workforce.
The current development characteristics of industrial robots are high speed, precision, compact body structure, multiple degrees of freedom, and increased rigidity. Key fields also require heavy loads or fast response times. For example, welding robots in automobile manufacturing mostly have a load capacity between 150-300 kg, while assembly robots in the electronics industry need to respond quickly to parts on the production line.
In the field of mechanical transmission, a speed reducer is an intermediate device connecting the power source and the actuator. Typically, it reduces the speed of high-speed power from motors, internal combustion engines, etc., by meshing a small gear on the input shaft with a large gear on the output shaft, thus transmitting greater torque. Currently, mature and standardized speed reducers include: cylindrical gear reducers, worm gear reducers, planetary reducers, planetary gear reducers, RV reducers, cycloidal pinwheel reducers, and harmonic reducers. Since the 1980s and 1990s, the development of emerging industries such as aerospace, robotics, and medical devices has created a demand for high-performance precision speed reducers with simple and compact structures, high power transmission, low noise, and smooth transmission. Among these, RV reducers and harmonic reducers are two important types of precision speed reducers.
Application areas of precision reducers
RV (Rot-Vector) reducer
The RV reducer was developed based on the cycloidal pinwheel transmission and features a two-stage reduction and a central disc support structure. Since its introduction to the market in 1986, it has become the go-to reducer for robots due to its advantages such as large transmission ratio, high transmission efficiency, high motion accuracy, small backlash, low vibration, high rigidity, and high reliability.
Harmonic reducer
Harmonic reducers consist of three parts: a harmonic generator, a flexible wheel, and a rigid wheel. Their working principle involves the harmonic generator causing controllable elastic deformation of the flexible wheel, which then meshes with the rigid wheel to transmit power and achieve speed reduction. Depending on the type of harmonic generator, there are cam-type, roller-type, and eccentric disc-type reducers. Harmonic reducers feature large transmission ratios, small overall dimensions, fewer parts, and high transmission efficiency. Single-unit transmission ratios can reach 50-4000, with transmission efficiencies as high as 92%-96%.
Planetary gear reducer
As the name suggests, a planetary gear reducer consists of three planetary gears rotating around a sun gear. Planetary gear reducers are small in size, lightweight, have high load-bearing capacity, long service life, smooth operation, and low noise. They feature power splitting and unique multi-tooth meshing characteristics; they are a widely used industrial product, with performance comparable to other military-grade planetary gear reducers, but at an industrial-grade price, making them suitable for a wide range of industrial applications.
The role of precision reducers in industrial robots
Industrial robots are typically powered by AC servo motors. Since these motors are driven by pulse signals and their speed can be adjusted, why do they still need speed reducers? Industrial robots often perform repetitive actions to complete the same processes. To ensure reliable task completion and process quality, high positioning and repeatability are required. Therefore, improving and ensuring the accuracy of industrial robots necessitates the use of RV reducers or harmonic reducers. Another function of precision reducers in industrial robots is to transmit greater torque. When the load is heavy, simply increasing the power of the servo motor is inefficient; a speed reducer can be used to increase the output torque within a suitable speed range. Furthermore, servo motors are prone to overheating and low-frequency vibration at low frequencies, which is detrimental to the accurate and reliable operation of industrial robots that operate for extended periods and in cyclical processes.
The presence of precision reducers allows servo motors to operate at appropriate speeds, precisely reducing the rotational speed to the required speeds for various parts of the industrial robot, increasing the rigidity of the mechanical body while outputting greater torque. Compared to general-purpose reducers, robot joint reducers require characteristics such as short transmission chains, small size, high power, light weight, and ease of control. Reducers widely used in articulated robots mainly fall into two categories: RV reducers and harmonic reducers.
Compared to harmonic reducers, RV reducers have higher rigidity and rotational accuracy. Therefore, in articulated robots, RV reducers are generally placed in heavy-load positions such as the base, upper arm, and shoulder; while harmonic reducers are placed in the forearm, wrist, or hand; planetary reducers are generally used in Cartesian coordinate robots.
