Adaptive sliding mode controller for an underactuated manipulator

A new type of adaptive sliding-mode control method (ASMC) for an underactuated manipulator called Pendubot is presented in This work. The ASMC adapts a kind of hierarchical structure. Firstly the Pendubot system is divided into two subsystems. For each subsystem, we define first-layer sliding plane. From these two first-layer sliding planes, we further define a second-layer sliding plane. Using Lyapunov law, we derive the sliding-mode control law and obtain the adaptive law of the sliding-mode controller's parameters. The control law can drive the system's states to their desired values, and implement anti-disturbance control. The paper also gives a stable analysis about the sub-sliding planes in theory, and the simulation results show the controller's validity and its adaptive abilities for the all kinds of extraneous disturbances.