Chattering-free Fast Fixed-time Sliding Mode Control for Uncertain Robotic Manipulators

다국어 초록 (Multilingual Abstract)

In this paper, we introduce a dynamic controller that dedicates fixed-time trajectory tracking for uncertain robotic manipulators. First, a new nonlinear function is designed and applied to the fixed-time sliding mode (FSM) surface. The derivative of the proposed nonlinear function is continuous, which can ensure the continuity and smoothness of the control torque, and it makes the sliding surface facilitate fast convergence rates of the system tracking error. Then, a FSM control scheme is designed using the proposed sliding mode surface. Combined the Lyapunov stability theory, we show that the proposed controller has fixed-time convergence independent of the initial state of the system. Moreover, the proposed control scheme is advantageous in that the control torque is continuous without transient change. This eliminates the chattering of uncertain robotic manipulators and makes the control torque smoother. Simulation results show that a faster error convergence rate can be obtained with a smaller control torque range. Finally, the above-mentioned effectiveness and superiority of the proposed control scheme are validated using simulations and experimental results.