An Adaptive Sliding Mode Control With Novel Sliding Variable-Based Adaptive Law for Disturbed Robot Manipulators

This paper tackles issues with controller synthesis of disturbed robot manipulators using adaptive sliding mode control (ASMC) and time-delay control (TDC) schemes. For robust control of dynamic system consisting of complex nonlinear functions, this paper proposes a novel ASMC method that uses a novel sliding variable-based adaptive law. The proposed adaptive law employs both function-based and rate-based decreasing law near the sliding surface to improve tracking performance while maintaining or even reducing chattering. The proposed sliding variable also incorporates additional terms for the position error and their time derivatives to compensate for time-delay estimation (TDE) errors induced from TDC methods. For the stability analysis of the robot manipulator controlled by the proposed ASMC, this paper proves uniformly ultimately bounded (UUB) stability of the sliding variable. Numerical simulation and experimental results demonstrate the effectiveness of the proposed ASMC in terms of tracking performance.