Sliding Mode Predictive Control of Flexible Air-Breathing Hypersonic Vehicles

A novel sliding mode control (SMC) strategy based on predictive technique is presented for flexible air-breathing hypersonic vehicles (FAHVs) with uncertainties and constraints. The vehicle dynamics are first introduced and then decoupled into two subsystems including velocity and altitude. Extended state observer (ESO)-based SMC schemes are designed for these two subsystems. For the original vehicle system, the sliding function is first designed using the pole placement technique. Then the sliding mode prediction model is corrected using the uncertainty estimation value. Finally, the constrained sliding mode control law is obtained using the quadratic programming method. A novel SMC system for the FAHV is established, which can handle system constraints and has forceful anti-disturbance ability. Compared with the SMC system based on ESO, the designed system based on predictive technique has advantages in terms of rapidity, control input and chattering. The feasibility and advantages of the presented control procedure are confirmed by simulations.