What is the structure of the robot's control system?

Today, the main framework structure of robots has been implemented. Its development is not a matter of one day or one night, but has been more than half a century. Let's talk about the composition and development of robots. Robots consist of three parts and six subsystems. The three parts refer to the mechanical part, the sensor part and the control part. The six subsystems refer to the drive system, the mechanical structure system, the perception system, and the robot-environment interaction system.

The drive system is a transmission device that is installed in each joint, that is, each degree of freedom of movement, in order to make the robot run. The drive system can be hydraulic drive, pneumatic drive, electric drive, or a comprehensive system that combines them. It can also be direct drive or indirect drive through mechanical transmission mechanisms such as synchronous belts, chains, gear trains, harmonic gears, etc.

The mechanical structure system of an industrial robot consists of three parts: the base, the arm, and the end effector. Each part has several degrees of freedom, forming a multi-degree-of-freedom mechanical system. If the base has a walking mechanism, it constitutes a walking robot; if the base does not have a walking and waist-turning mechanism, it constitutes a single robot arm. The arm generally consists of three parts: the upper arm, the lower arm, and the wrist. The end effector is an important component directly mounted on the wrist. It can be a two-finger or multi-finger gripper, or a work tool such as a paint spray gun or welding tool.

The perception system includes internal sensor modules and external sensor modules, which are used to obtain valuable information about the internal and external environmental states. The use of intelligent sensors improves the mobility, adaptability and intelligence of robots. Although the human perception system is extremely sensitive to the external world, for some special information, sensors are more accurate than the human perception system.

The role of the robot-environment interaction system is to achieve mutual connection and coordination between industrial robots and equipment in the external environment. The industrial robot and external equipment can be integrated into a functional unit, such as a processing and manufacturing unit, a welding unit, an assembly unit, etc. Of course, multiple robots, multiple machine tools or equipment, multiple parts storage devices, etc. can also be integrated into a functional unit to perform complex tasks.

The function of the human-computer interaction system is to enable operators to participate in robot control and communicate with the robot. For example, standard computer terminals, command consoles, information display boards, danger signal alarms, etc. The system can be divided into two categories, namely command giving devices and information display devices.

The function of the control system is to control the robot's actuators to complete the specified movements and functions according to the robot's operating instruction program and the signals fed back from the sensors. If the industrial robot does not have an information feedback function, it is an open-loop control system; if it has an information feedback function, it is a closed-loop control system. According to the control principle, the control system can be divided into program control system, adaptive control system and artificial intelligence control system. According to the form of controlled movement, the control system can be divided into point control and trajectory control.

By the way, let's talk about the development of robots around the world. In 1954, American Devol first proposed the concept of industrial robots and applied for a patent. The key to this patent is to use servo technology to control the joints of the robot, teach the robot's movements with the help of human hands, and the robot has the function of recording and reproducing movements. This is the so-called teaching and reproducing robot, and most of the existing robots use this control method. Joseph F. Engel Berger, known as the "father of industrial robots", founded the world's first robot company, Unimation, in 1958 and participated in the design of the first Unimate robot. The robot is a five-axis hydraulic drive robot used for die-casting operations, and the control of the arm is completed by a dedicated computer.

It uses discrete CNC components and is equipped with a magnetic drum to store information, and can memorize and complete 180 work steps. During this period, another American company, AMF, also began to develop the Versatran industrial robot. It is mainly used for material transportation between machines and is hydraulically driven. The robot's arm can rotate around the base, rise and fall in the vertical direction, and can also extend and retract in the radial direction. Under normal circumstances, Unimate and Versatran can be considered the earliest industrial robots in the world. The control methods of these two industrial robots are roughly similar to those of CNC machine tools, but their appearance features are very different, and they are mainly composed of human-like hands and arms. The development history of industrial robots is shown in Table 1-1 below.

In short, robots are an important symbol of modern scientific and technological progress and a concrete manifestation of a country's comprehensive national strength.