Robust trajectory tracking control of robotic manipulators based on model-free PID-SMC approach

Abstract

In this paper, a robust controller based on proportional-derivative control and sliding mode control for trajectory tracking problem of a nonlinear robotic manipulator is presented. Actuator dynamics is taken into account in tracking control simulations for verification of good precision trajectory tracking. A low pass filter is employed for the elimination of chattering, high frequency components, and noises. The proposed control scheme combines the simplicity feature of the proportional-integral-derivative (PID) controller and the robustness feature of the sliding mode control (SMC). There is no need to know the dynamic model of controlled systems, unlike most robust controllers, and only the upper bound of the dynamic system is required in the proposed method. Lyapunov’s stability method is used to prove robustness of the proposed controller for the robot manipulator subjected to system uncertainties and external disturbance. The performance of the proposed controller is simulated by MATLAB-Simulink environment and is compared with other control schemes to verify its efficiency with various control methods commonly preferred in robotic manipulators. Robustness tests of the proposed controller against uncertainties in robot and actuator dynamics and external disturbance are illustrated.