Adaptive immersion and invariance based control of non-minimum phase hypersonic vehicles

A novel adaptive control design based on the immersion and invariance (I&I) theory is presented for the non-minimum phase hypersonic vehicles with parameter uncertainties. The vehicle dynamics are first divided into the velocity subsystem, the altitude/flight-path angle subsystem and the angle of attack/pitch rate subsystem. Then three I&I based adaptive controllers are designed for each subsystem respectively. The key feature of the proposed control scheme lies in the construction of the estimator, which can be used to assign prescribed dynamics to the estimate errors. The interaction of the flexible modes with the rigid dynamics is considered in both the synthesis of the controller and the analysis of the closed-loop system. A complete stability analysis of the closed-loop system is presented using Lyapunov theory. Simulation results show that the proposed control system provides precise and robust tracking of the velocity and altitude commands, as well as accurate regulation of angle of attack.