Control System Of Robot Joint Based On Active Disturbance Rejection Contorller

With the development of robot control technology, there are more requirements to robot joint servo system’s position accuracy, rapidity and anti-jamming capability. Using a reasonable and effective control strategy to improve the static performance and dynamic performance has become the core content of the robotics research.An Active Disturbance Rejection Controller(ADRC) is adopted to control joint of robot. The result of simulations show that ADRC has low request to the model accuracy and good adaptability for the change of the model parameters and external disturbance. A method using model compensation was designed for more accurately joint servo system. The simulation shows that the system has a rapidly response, a good tracking ability, and anti-jamming capability. The major work and results are as follows:1. Mechanical structure of robot joint composed of a DC torque and a harmonic reducer is introduced. Mechanical properties are simulated to find that the joint system has a rapid response and a good regulation characteristic.2. A dynamic equation was generated by four degree of freedom(4-DOF) robotics dynamics analysis and simulation. Validity of the proposed modeling is valid by simulation, the basis for the following joint torque analysis and control was provided.3. It is established control model of robot joint based on ADRC, ADRC with model compensation respectively. Compared with classic PID controller, ADRC and ADRC with model compensation advantage and disadvantage through simulation. ADRC based on model compensation could improve the accuracy of the extended state observer when part of disturbance model was known in the system, and get better control precision.based on decentralized ADRC. Four ADRC separately control of4-DOF robot joints could compensate robotic coupling torque. Combined with robot dynamics analysis, a ADRC based on gravity compensation for4-DOF robot system was proposed. This servo system has better servo ability, disturbance rejection ability and high steady-state accuracy.The simulation shows that decentralized structure ADRC system has good static performance and anti-disturbance ability. This theory could be used to study the complete decoupling of the robot dynamics model and disturbance compensation, to further improve the performance of the robot system.