Sliding mode control applied to robotic actuators

Abstract

Actuators have nonlinearities that add difficulties to the control performance. The main one is the nonlinear friction that causes the dead zone in torque and stick-slip behavior. All these problems hamper the design of control laws. The variable structure control (sliding mode control) is suitable for systems with non-modeled or unknown dynamics. This paper compares three different implementations of control, PID, Sliding Mode with simple surface and Sliding Mode with integral surface. The simulations showed that both the PID control as the control with integral surface showed a great performance in trajectory tracking, considering non-linear friction in the dynamics of the actuator. However, the variable structure control with simple surface did not show the same performance.