Command Filtered Adaptive Asymptotic Tracking Control of Nonlinear Systems With Unknown Control Directions via Logic-Based Switching

This article focuses on the command-filtered-based asymptotic tracking control problem of uncertain nonlinear systems with mismatching disturbances. Different from the previous command filtered control results, the control directions are assumed to be unknown, and a novel logic-based switching method is presented to handle them instead of the classical Nussbaum function method. Besides, some smooth functions are introduced into the virtual controllers to compensate the unknown disturbances. Then, an adaptive tracking controller with dynamic parameter is proposed for the considered nonlinear system. With the aid of the supervisory function, a logic-based switching algorithm is developed to regulate the dynamic controller parameter. Furthermore, it is shown that asymptotic tracking control can be achieved for the considered system with finite switchings. Finally, a simulation example is given to verify the effectiveness of the novel design scheme. Note to Practitioners —This paper aims at presenting a novel asymptotic tracking control scheme for uncertain nonlinear systems with unknown control signs and external disturbances, which can model most practical systems such as spacecraft with actuation sign errors. Although considerable command filter control results have been obtained for nonlinear systems, it is still challenging and difficult to realize the command filter asymptotic tracking control of nonlinear system with multiple unknown control signs. To this end, switching functions with dynamic parameter are introduced to design the compensation signals and controller. Besides, an effective switching algorithm is proposed to regulate the dynamic parameters. Based on the proposed control scheme, the command filter control problem can be handled for nonlinear system with multiple unknown control signs. Besides, some smooth functions are also utilized to compensate the mismatching disturbances such that the asymptotic tracking control can be realized. It is worth pointing out that our proposed control method has potential application in practical systems including spacecraft and autonomous underwater vehicles.