Sliding Mode Control with Dirty Derivatives Filter for Rigid Robot Manipulators

Although Sliding Mode Control (SMC) is shown to be a powerful method for the control of rigid robotic manipulators, it comes with disadvantages. One disadvantage is related to the fact that the terminal sliding variable vector has a nonlinear term of the velocity error. Consequently, inaccurate velocity estimation may lead to chattering phenomenon that can excite unmodeled high-frequency plant dynamics yielding to either severe vibrations in the arm or instability of the control system. To better overcome such a drawback, this paper proposes the integration of dirty derivatives filter with SMC instead of using "direct" velocity estimation methods. We justify the effectiveness of our proposed approach numerically and experimentally on a four-degree-of-freedom (DOF) robot manipulator while considering a classical SMC and two adaptive SMCs.