Tracking control of a robot manipulator using sliding mode controller with fast and accurate performance

In a variable structure control algorithm, sliding mode makes the closed loop system insensitive to modelling uncertainties and external disturbances. However due to imperfections in switching, the system trajectory chatters, which is very undesirable, and the insensitivity property of a sliding mode controller is present only when the system is in the sliding mode. To overcome this shortcoming, a sliding mode control algorithm using time-varying sliding surface and PID-like structure is proposed. This controller guarantees robustness during the whole period of control and removes chattering and also reduces steady state error of the system. To demonstrate its performance, the proposed control algorithm is applied to a two link robot manipulator