Trajectory Verification and Control of 5R Spherical Parallel Mechanism for Neurosurgeries

Abstract

The main subject of this paper is modeling, kinematic verification, and control simulation of a 5R (five revolute) spherical parallel manipulator. This manipulator is a closed chain remote-center-of-motion (RCM) mechanism with two rotational degrees of freedom. To avoid the complexity of calculations required for dynamic modeling and forward kinematic analysis MATLAB/Simscape is used. Active joint PID controller and trajectory feedback plus feedforward controller are applied on the dynamic model generated by Simscape to control and track the trajectory of the end effector. PID controller resulted in a maximum absolute error of 3.24*10-2 degrees and 8.74*10-3 degrees in azimuth angle and inclination angle, respectively. Finally, after applying the trajectory feedback plus feedforward controller, the maximum absolute error is decreased by 50.26% and 27.2% in azimuth and inclination angle, respectively.