Research On Parameter Adaption And Compensation Control Of SCARA Robot

SCARA robot is a typical industrial robot, it is widely used in automatic production with its advantages of high speed and high precision. Due to the changing working environment of industrial robots in practical application, the system parameters change and are easily to be effected with the random disturbance. Without exact solution of systematic parameters of robot, adaptive control method makes the system achieve good control performance through on-line identification, which has stronger robustness and has a greater advantage in the control of industrial robots. This paper focuses on the key problems of the SCARA robot, including the kinematics of the robot, the system parameters adaptive control, the compensation controller design and the tracking control experiment.Firstly, the system model of SCARA robot is studied in this paper. The kinematics was modeled according to DOF configuration and structure size of SCARA robot and the positive and inverse kinematics was analyzed, and the inverse kinematics is proposed to meet the requirements to practical application. Because of the joint type robot kinematics singularity, the singular position of the robot was analyzed and solved, and damping angular was introduced to suppress acceleration so that the robot cannot reach singular pose.Second, the system dynamics model of robot was established, and the model was simplified according to the purpose of application of SCARA robot. To solve robotic system parameter uncertain problems, indirect adaptive control and the composite adaptive control of trajectory tracking algorithm is proposed, torque prediction error was used to update the system parameters, which makes parameters satisfy the control requirement of the system, On the basis of which, a dynamic trajectory tracking controller is designed and it can track the trajectory of the robot, and the two methods are compared and analyzed.Third, aiming at the problems of external disturbance in industrial robot system, the tracking precision and rapidity were proposed as the design criteria of the controller. By introducing the standard error signal as the state variable of the system, nonlinear dynamic compensation was designed, which compensates the system uncertain conditions from outside, to realize the control of robot joint space trajectory tracking. The asymptotic stability of compensation controller was proved.Finally, to verify the feasibility of adaptive tracking method and compensation controller, a SCARA robot servo experiment system based on PC was established. With the robot system parameters uncertainty and external disturbance, the trajectory tracking experiments were carried out. The results showed that the uncertain system parameters adaptive tracking control was achieved and the random disturbance from outside was compensated.