PID-SMC controller for a 2-DOF planar robot

Sliding mode controller (SMC) is considered as a robust control method. In this paper, a combination of SMC and traditional proportional-integral-differential (PID) control scheme for a 2-degree of freedom (2-DOF) planar manipulator is considered. Since the PID control does not require precise system modelling, a sliding mode surface for the SMC control is designed using the PID component parameters of the manipulator. The PID control adjusts the errors of the closed loop system and the SMC control ensures fast convergence towards the sliding mode surface. Hence, this hybrid controller possesses features of both control schemes and obtains better system stability.