Sliding mode control of position commanded robot manipulators

This paper investigates the method of implementing dynamic controller on a manipulator which do not have direct drive joints. A previously proposed torque to position conversion method for servo actuated robot manipulators is used with an adaptive backstepping based sliding mode controller for dynamic trajectory tracking control. The proposed controller uses a nonsingular finite time sliding surface to achieve finite time stability as well as higher tracking performance. To avoid a structurally complex control law as well as obtain partial model independency of the controller, the soft nonlinearities of the manipulator are estimated using the time delay control philosophy where delayed signals are used to estimate the model nonlinearities. The entire system is validated using simulation and experimental studies.