Robust PID Control for Robot Manipulators with Parametric Uncertainties

Abstract

Most of the industrial robots use a classical PIDtype controller for positioning tasks. A main reason for this is its effectiveness in regulation tasks, simple linear structure, and easy implementation. Moreover, it is well known that the robustness properties of a PID controller make it an excellent choice for set point control of robot manipulators. In this paper, a robust PID controller is designed in order to cope with modeling uncertainties and unmodelled dynamics. First, dynamic model of robot manipulator is derived using the Rodriquez approach. Then, a PID controller is applied to feedback linearized robotic system in order to suppress constant disturbance and achieve good set-point control. The proposed controller contains one adjustable parameter lamda , which has a direct influence on the time constant of the closed loop system. By adjusting it, one can accomplish a compromise between the robustness and performance indices. Using this algorithm, simulation results of a NeuroArm robotic manipulator executing positioning tasks are shown to demonstrate the efficiency of the proposed controller.