Finite-time sliding mode joint positioning error constraint control for robot manipulator in the presence of unknown deadzone

This paper proposes two tracking error constraint finite-time sliding mode control schemes for unknown manipulator parameters with deadzone input nonlinearity. A transformed filtered tracking error surface was first constructed as a separated form to guarantee the predefined tracking performance. Next, a simple transformed prescribed error surface was considered to obtain the same predefined tracking performance. Both proposed controls adopt Finite-time sliding mode control (FSMC) with a non-model-based manipulator feedforward method to achieve rapid error convergence and fast control design. Unlike conventional controls with deazone compensation, the proposed controls are robust to deadzone nonlinearity without adding extra compensators. The effectiveness of the proposed scheme was proven by simulation and experimental evaluations for an articulated manipulator system with unknown deadzone and friction.