Robust tracking control of a three-degree-of-freedom robot manipulator with disturbances using an integral sliding mode controller

Robot systems often face highly nonlinear manipulator dynamics and uncertainties such as external disturbances, payload variations, and end effector modeling errors. Therefore, it is of great industrial importance to compute and simulate the dynamic response of these manipulators in a reliable manner. This research investigates a robust control strategy—Integral Sliding Mode Control (ISMC)—applied to a three-degree-of-freedom robot manipulator with external disturbances. The study consists of two stages. The first stage uses Proportional-Derivative (PD) control with dynamically calculated weight values in the absence of the external disturbances. In the second stage, ISMC is employed to address dynamic responses to disturbances. The computation work on the model is implemented in Mathematica software, and a three-joint SCARA-type robot is tested to demonstrate methodology robustness. In the end, stability is ensured through Lypunove function analysis and the sliding surface's phase portrait.