Prescribed Performance-Based Predefined-Time Sliding Mode Control for Hypersonic Vehicles

This paper presents a systematic design of a predefined-time sliding mode controller with integrated prescribed performance strategies, tailored to the longitudinal dynamics of hypersonic vehicles (HSVs) operating under strict real-time and high-precision requirements. A prescribed error transformation function is introduced to simultaneously constrain both transient and steady-state behaviors. This transformation converts the original constrained tracking problem into an equivalent unconstrained stabilization problem, thereby simplifying the controller synthesis. Based on the decomposed control-oriented state-space equations, separate sliding mode controllers are designed for the velocity and attitude subsystems. The proposed strategy guarantees that the tracking errors converge to zero within a user-predefined time, while strictly satisfying the prescribed performance bounds at every stage of the closed-loop response. The efficacy of the method is validated through numerical simulations.