Understand the structure, drive and technical indicators of industrial robots in one article

3. Classification of robot control:

1) According to whether there is feedback or not, it is divided into: open-loop control and closed-loop control; the conditions for open-loop precise control: the model of the controlled object is accurately known, and this model remains unchanged during the control process.

2) According to the expected control quantity, it is divided into: position control, force control, and mixed control; position control is divided into: single joint position control (position feedback, position velocity feedback, position velocity acceleration feedback), multi-joint position control, and multi-joint position control is divided into decomposed motion control and centralized control; force control is divided into: direct force control, impedance control, and force-position mixed control; 3) Intelligent control methods: fuzzy control, adaptive control, optimal control, control, fuzzy neural network control, expert control, and others;

4. Control system configuration and structure:

Since the robot control process involves a large number of coordinate transformations and interpolation operations as well as lower-level real-time control, most of the current robot control systems use a hierarchical microcomputer control system in structure, usually a two-level computer servo control system.

1) Specific process:

After receiving the work instructions input by the staff, the main control computer first analyzes and interprets the instructions to determine the movement parameters of the hand.

Then, kinematics, dynamics and interpolation operations are performed, and finally the coordinated motion parameters of each joint of the robot are obtained. These parameters are output to the servo control level through the line as the given signal of the servo control system of each joint. The joint driver converts this signal into D/A and drives each joint to produce coordinated motion. The sensor feeds back the motion output signal of each joint to the servo control level computer to form a local closed-loop control, so as to more accurately control the motion of the robot hand in space.

2) Two control modes of motion control based on PLC:

1. Use pulse output instructions to generate pulses to drive the motor using certain output ports of the PLC, and use general I/O or counting components to achieve closed-loop position control of the motor.

2. Using the PLC external expansion position control module to realize the closed-loop position control of the motor is mainly to send high-speed pulses, which belongs to the position control method. Generally, there are more point-to-point position control methods.

Review editor: Tang Zihong