Adaptive sliding mode control design for a hypersonic flight vehicle

A multi-input/multi-output adaptive sliding controller is designed and analyzed for the longitudinal dynamics of a generic hypersonic air vehicle. This vehicle model is nonlinear, multivariable, and unstable and includes uncertain parameters. Simulation studies are conducted for trimmed cruise conditions of 110,000 It and Mach 15 where the responses of the vehicle to a step change in altitude and airspeed are evaluated. The commands are 100-ft/s step velocity and 2000-ft step altitude. The controller is evaluated for robustness with respect to parameter uncertainties using simulations. Simulation studies demonstrate that the proposed controller is robust with respect to parametric uncertainty and meets the performance requirements with relatively low-amplitude control inputs.