Adaptive Sliding-Mode Disturbance Observer-Based Finite-Time Control for Unmanned Aerial Manipulator With Prescribed Performance

In this article, an adaptive sliding-mode disturbance observer (ASMDO)-based finite-time control scheme with prescribed performance is proposed for an unmanned aerial manipulator (UAM) under uncertainties and external disturbances. First, to take into account the dynamic characteristics of the UAM, a dynamic model of the UAM with state-dependent uncertainties and external disturbances is introduced. Then, note that a priori bounded uncertainty may impose a priori constraint on the system state before obtaining closed-loop stability. To remove this assumption, an ASMDO with a nested adaptive structure is introduced to effectively estimate and compensate the external disturbances and state-dependent uncertainties in finite time without the information of the upper bound of the uncertainties and disturbances and their derivatives. Furthermore, based on the proposed ASMDO, the finite-time control scheme with the prescribed performance is presented to ensure finite-time convergence and implement the specified transient and steady-state performance. The Lyapunov tools are utilized to analyze the stability of the proposed controller. Finally, the correctness and performance of the proposed controller are illustrated through numerical simulation comparisons and outdoor experimental comparisons.