The six subsystems can be divided into mechanical structure system, drive system, perception system, robot-environment interaction system, human-computer interaction system and control system.

1. Mechanical structure system
From the perspective of mechanical structure, industrial robots are generally divided into tandem robots and parallel robots. The characteristic of a tandem robot is that the movement of one axis will change the coordinate origin of another axis, while the movement of one axis of a parallel robot will not change the coordinate origin of another axis. The early industrial robots all used a series mechanism. A parallel mechanism is defined as a closed-loop mechanism in which a moving platform and a fixed platform are connected by at least two independent motion chains, the mechanism has two or more degrees of freedom, and is driven in parallel. The parallel mechanism has two components, which are the wrist and the arm. The area of movement of the arm has a great impact on the space of movement, and the wrist is the connecting part of the tool and the body. Compared with tandem robots, parallel robots have the advantages of high stiffness, stable structure, large bearing capacity, high micro-motion accuracy and small motion load. In terms of position solving, the forward solution of the tandem robot is easy, but the reverse solution is very difficult, while the parallel robot is the opposite, the positive solution is difficult, but the reverse solution is very easy.

2. Drive system
A drive system is a device that provides power to a mechanical structural system. According to different power sources, the transmission mode of the drive system is divided into four types: hydraulic, pneumatic, electric and mechanical. Early industrial robots were hydraulically driven. Due to the problems of leakage, noise and instability at low speeds in the hydraulic system, and the bulky and expensive power unit, only large heavy-duty robots, parallel processing robots and some special applications use hydraulically driven industrial robots. Pneumatic drive has the advantages of fast speed, simple system structure, convenient maintenance and low price. However, the working pressure of the pneumatic device is low, and it is not easy to accurately position, so it is generally only used for the drive of the end effector of industrial robots. Pneumatic grippers, rotary cylinders and pneumatic suction cups are used as end effectors for small and medium-sized workpiece gripping and assembly. Electric drive is a kind of driving mode that is used the most at present, and its characteristics are that the power supply is convenient, the response is fast, the driving force is large, the signal detection, transmission, processing is convenient, and a variety of flexible control modes can be adopted, the driving motor generally adopts a stepper motor or a servo motor, and the direct drive motor is also used at present, but the cost is higher, and the control is also more complex, and the reducer that matches the motor generally adopts harmonic reducer, cycloidal pin wheel reducer or planetary gear reducer. Due to the large number of linear drive requirements in parallel robots, linear motors have been widely used in the field of parallel robots.

3. Perception system

4. Robot-environment interaction system
The robot-environment interaction system is a system that realizes the interconnection and coordination between the robot and the equipment in the external environment. The robot and external equipment are integrated into a functional unit, such as a processing and manufacturing unit, a welding unit, an assembly unit, etc. Of course, it can also be a functional unit that integrates multiple robots to perform complex tasks.

5. Human-computer interaction system
The human-computer interaction system is a device for humans to connect with robots and participate in robot control. For example: the computer's standard terminal, command console, information display board, danger alarm, etc.

6. Control system
The task of the control system is to control the actuator of the robot to complete the specified movements and functions according to the robot's operation instructions and the signals fed back from the sensors. If the robot does not have information feedback characteristics, it is an open-loop control system, and if it has information feedback characteristics, it is a closed-loop control system. According to the control principle, it can be divided into program control system, adaptive control system and artificial intelligence control system. According to the form of control movement, it can be divided into point control and continuous trajectory control.