Adaptive Predefined-Time Prescribed Performance Control With Application to a Quadrotor UAV

This article considers an adaptive predefined-time prescribed performance control problem for a class of uncertain nonlinear systems with prescribed constraints, external disturbances, nonlinear dynamics, and an unknown control coefficient, which has significant value in theory and practice. First, a predefined-time prescribed performance function is integrated into the backstepping control to satisfy both transient-state and steadystate constraints. Compared to current predefined-time stable systems, a modified predefined-time stable system is proposed, capable of accelerating convergence speed and enhancing design flexibility. Building on this foundation, an adaptive signal filter and a filtering compensation system are developed systematically by using continuous functions, which improve control accuracy, solve the “explosion of complexity” issue, and avoid chattering. In addition, adaptive techniques and fuzzy identification are used to estimate the lumped disturbance and unknown control coefficient while compensating for nonlinear functions, thereby eliminating the requirement for prior knowledge of the system dynamics. The stability analysis shows that the control error converges to a prescribed boundary in a predefined interval. Finally, the superiority of the presented control scheme is verified through comparative results on the trajectory tracking control of a quadrotor unmanned aerial vehicle.