A new method for tuning PID parameters of a 3 DoF reconfigurable parallel kinematic machine

Aimed at a 3-DoF reconfigurable parallel kinematic machine, a method for tuning PID parameters of its servo system is presented. At first, position, velocity and acceleration inverse solution models of machine driven by the outer translation pairs that contain parallelogram strut structures are developed, and the inverse dynamics model of the rigid body has been set up by means of virtual work principle. Based on the above, making the mean square error of the trajectory of the moving platform least as the optimum goal, and considering the real-timely variational inertial load along with its pose at the same time, the overshoot, adjusting time of the unit step response of the servo system and the optimum range of PID parameters are given through simulations. At last, the correctness and effectiveness of the method are proved by the experiments.