Sliding Mode Decoupling Control of Near-Space Vehicle

The six degrees of freedom(Six-DoF) near-space glide vehicle model is obtained.This vehicle model is time variant,coupling,highly nonlinear and uncertain parameters included.To combine the decoupling and robustness and improve the performance of control system,a multi-input/multi-output sliding mode decoupling controller is proposed.The controller includes two parts,one is the inner loop decoupling controller and the other is the outer loop robustness controller.The inner-loop controller based on dynamic inversion is designed,by which input/output linearization of rotation motion model is achieved.The outer-loop sliding mode controller based on sign function is designed,and it is robust to outside interference and parameter uncertainties.The saturation function is applied to reduce the chatter of the slide mode.The simulation studies are conducted for the response of the commands of angle of attack,sideslip angle and bank angle.The controller is evaluated for robustness with respect to interference and parameter uncertainties by using simulations.Simulation studies demonstrate that the proposed controller is robust with respect to interference and parametric uncertainty and meets the performance requirements with acceptable control inputs.