Adaptive backstepping sliding mode controller with PID sliding surface for a co-ordinated links (COOL) robotic arm

Abstract

This paper proposes an adaptive backstepping sliding mode controller with proportional integral derivative (PID) sliding surface for trajectory tracking control of a 6 degrees of freedom (DOF) robotic manipulator. A backstepping controller is combined with a sliding mode controller for imparting robustness against both matched and mismatched uncertainties. For ensuring fast transient response, a PID sliding surface is used. Chattering in the control input, which is inherent in the first order sliding mode, is reduced by using a constant plus proportional reaching law. Unknown uncertainty present in the system is tackled by tuning the controller gain adaptively. Experiments are conducted on a 6 DoF co-ordinated links (COOL) robotic arm. Experimental results are in agreement with simulation results which validate the proposed controller algorithm.