An industrial robot consists of three main parts and six subsystems. The six subsystems can be divided into mechanical structure system, drive system, perception system, robot-environment interaction system, human-machine interaction system, and control system.
1. Mechanical structure system
From a mechanical structure perspective, industrial robots are generally divided into serial robots and parallel robots. A serial robot is characterized by the fact that movement on one axis changes the origin of the coordinate system on another axis, while movement on one axis in a parallel robot does not change the origin of the coordinate system on the other axis. Early industrial robots all used serial mechanisms. A parallel mechanism is defined as a closed-loop mechanism in which the moving platform and the stationary platform are connected by at least two independent kinematic chains, the mechanism has two or more degrees of freedom, and is driven in parallel.
2. Drive system
A drive system is a device that provides power to a mechanical structure system. Based on the power source, drive systems are classified into four types: hydraulic, pneumatic, electric, and mechanical. Early industrial robots used hydraulic drives. However, due to problems such as leakage, noise, and low-speed instability, as well as the bulky and expensive power units, hydraulically driven industrial robots are currently only used in large, heavy-duty robots, parallel processing robots, and some special applications.
3. Sensing System
Robot perception systems transform various internal state and environmental information of the robot from signals into data and information that the robot itself or other robots can understand and apply. Besides sensing mechanical quantities related to its own working state, such as displacement, velocity, and force, visual perception technology is a crucial aspect of industrial robot perception. Visual servo systems use visual information as feedback signals to control and adjust the robot's position and posture. Machine vision systems are also widely used in quality inspection, workpiece identification, food sorting, and packaging. Perception systems consist of internal and external sensor modules; the use of intelligent sensors improves the robot's mobility, adaptability, and intelligence.
4. Robot-Environment Interaction System
A robot-environment interaction system is a system that enables robots to communicate and coordinate with devices in their external environment. Robots and external devices are integrated into a single functional unit, such as a manufacturing unit, welding unit, or assembly unit. Alternatively, multiple robots can be integrated into a single functional unit to perform complex tasks.
5. Human-computer interaction system
Human-computer interaction systems are devices that allow humans to communicate with robots and participate in robot control. Examples include standard computer terminals, command consoles, information display panels, and danger signal alarms. [3]
6. Control System
The task of a control system is to direct the robot's actuators to perform prescribed movements and functions based on the robot's operational instructions and signals fed back from sensors. If the robot lacks feedback capabilities, it is an open-loop control system; if it does, it is a closed-loop control system. Based on control principles, control systems can be categorized into program control systems, adaptive control systems, and artificial intelligence control systems. Based on the form of motion control, they can be classified as point-to-point control and continuous trajectory control.
