Fuzzy Adaptive Prescribed Performance Fault-Tolerant Control for HFVs with Fixed-Time Convergence Guarantee

Abstract

A new fixed-time fuzzy adaptive fault-tolerant control methodology is proposed for the longitudinal dynamics of hypersonic flight vehicles (HFVs) in the presence of actuator faults, uncertain dynamics, and external disturbances. In contrast with the conventional fixed-time control schemes that typically contain the fractional powers of errors in their designs, this work develops a low-complexity control structure in the sense of removing the dependence on the need of abovementioned fractional power terms by means of prescribed performance control (PPC) method. Different from the most existing PPC approaches where the initial conditions of tracking errors are required to be known, the newly proposed prescribed performance function (PPF) can relax such restrictions through choosing properly small initial values of PPF. Fuzzy logic systems (FLSs) are employed to handle unknown dynamics, and minimal learning parameter (MLP) technique is incorporated into the design for the purpose of alleviating computation burden. Closed-loop stability is rigorously proved via Lyapunov stability theory, and simulation results are eventually given to validate the effectiveness of the proposed control strategy.

Fixed-time angle of attack constrained control for aircraft considering dynamic icing process

“…On the basis of the finite-time controller, it adds a fractional power term about the tracking error (the power index is greater than 1), so that the convergence time of the tracking errors does not depend on the initial value of the system 10 – 13 . Fixed-time tracking control has the advantage of making the system fast and stable, which has important theoretical and application value in the design of flight control system 14 , 15 . However, there is little literature on the fixed-time robust control for icing aircraft.…”