Sequential Loop Closure Based Adaptive Autopilot Design for a Hypersonic Vehicle

This paper presents a sequential loop closure approach to designing a velocity and altitude tracking autopilot for a hypersonic vehicle. The control architecture consists of two decoupled control subsystems, one for velocity, the other for altitude. The velocity control subsystem consists of an adaptive augmented baseline controller. The altitude control subsystem consists of an adaptive inner-loop designed to accommodate uncertainties in the stability and control derivatives of the aircraft, and track pitch-rate commands. The outer-loop is designed independent of the inner loop, and guarantees stability of the closed-loop system. The outer-loop uses components of a closed-loop reference model, and generates the appropriate pitch-rate commands for the inner loop such that the hypersonic vehicle tracks the desired altitude. A numerical example based on a scramjet powered, blended wing-body generic hypersonic vehicle model is presented, demonstrating the efficacy of the proposed control design.