Extended state observer-based generalized super-twisting control for flexible hypersonic vehicles

This paper investigates the anti-disturbance control design for flexible air-breathing hypersonic vehicles (FAHVs). Firstly, a control-oriented FAHV model is obtained using input-output linearization theory. Then, linear extended state observers (LESOs) with time-varying bandwidth parameters are developed to estimate and compensate the lumped disturbances of the FAHV system in real time. Time-varying bandwidths allow LESOs to resolve the conflict between peaking and rapidity. In addition, a generalized super-twisting (GSTW) sliding mode controller is designed by replacing the conventional discontinuous switching term with a nonsmooth term to track the desired velocity and altitude. The proposed GSTW control scheme can effectively eliminate unfavorable chattering problems. Finally, extensive comparative simulations are provided to demonstrate the feasibility and superiority of the proposed control scheme.