Industrial robots consist of three basic parts: the body, the drive system, and the control system. The body comprises the base and actuators, including the arm, wrist, and hand; some robots also have a locomotion mechanism. Most industrial robots have 3 to 6 degrees of freedom, with the wrist typically having 1 to 3. The drive system includes the power unit and transmission mechanism, used to enable the actuators to perform corresponding movements. The control system issues command signals to the drive system and actuators according to the input program and performs control. Industrial robots are classified into four types based on the movement of their arms: Cartesian coordinate arms can move along three Cartesian coordinates; cylindrical coordinate arms can perform lifting, rotation, and extension/retraction movements; spherical coordinate arms can rotate, pitch, and extend/retract; and articulated arms have multiple rotary joints.
Industrial robots can be classified into point-to-point and continuous trajectory types based on their control functions of the actuator's movement. Point-to-point robots only control the accurate positioning of the actuator from one point to another, and are suitable for machine tool loading and unloading, spot welding, and general handling and loading/unloading operations. Continuous trajectory robots can control the actuator to move along a given trajectory, and are suitable for continuous welding and painting operations.
Industrial robots can be categorized into two types based on their program input method: programmed input type and teach-in input type. Programmed input type robots transmit pre-written program files from a computer to the robot control cabinet via RS232 serial port or Ethernet communication methods.
There are two teaching input methods: one is where the operator uses a manual controller (teaching pendant) to transmit command signals to the drive system, causing the actuator to perform the required sequence of actions and motion trajectory; the other is where the operator directly leads the actuator to perform the required sequence of actions and motion trajectory. During the teaching process, the working program information is automatically stored in the program memory. When the robot works automatically, the control system retrieves the corresponding information from the program memory and transmits command signals to the drive mechanism, causing the actuator to reproduce the taught actions.
Industrial robots that use teach-input programs are called teach-and-playback industrial robots. Industrial robots with tactile, force, or simple vision capabilities can work in relatively complex environments; if they have recognition functions or further adaptive and self-learning functions, they become intelligent industrial robots. They can adapt to the environment by selecting or programming themselves according to "macro instructions" given by humans and automatically complete more complex tasks.
