Research Of Control Method Based On Sliding Mode Control For Hypersonic Aircraft

Hypersonic aircraft has the characteristics of large range and high maneuver which flight speed is five times higher than the speed of sound. The new aircraft has great military and economic value that the major world powers focus on development of it. Moreover, the aircraft has many other characteristics such as strong nonlinear, uncertainty, strong coupling,fast time varying and the interference characteristics, which make the design of control system difficult, a new control method and mean should be introduced into the design of aircraft control system. In recent years, due to the advantages of nonlinear system specific interference immunity, the sliding mode control algorithm is favored by the majority of scholars. If the sliding mode control algorithm could be applied to the study on the method of hypersonic flight vehicle control, it would enhance the stability of the control system and improve the control precision. Based on hypersonic flight vehicle nonlinear, the influence of parameter uncertainty and external disturbance, a new type of nonsingular terminal sliding mode controller is designed that can effectively restrain the effect and fast track the instruction signals, the chattering phenomenon is overcome. According to the linear model of hypersonic vehicle longitudinal input/output, a disturbance compensation hierarchical sliding mode control method is designed in view of the system uncertainty and the actuator with dead zone of nonlinear problems. It realized the speed and the stability of the high speed tracking,and ensured the rapidity and robustness of the control system.The motion model of hypersonic aircraft control system is established, and the air force and air dynamic torque equations are given. Based on the open loop characteristic of this system analyzed, the strong coupling between the system states is known. Especially, the rate of roll and yaw rate would have a significant impact on the states. Then a simplified affine nonlinear model is put forward.Aimed at hypersonic flight vehicle nonlinear, parameter uncertainties and the larger external disturbance,the design of a new kind of nonsingular terminal sliding mode controller is designed, it could realize the finite time stable and finite time convergence to equilibrium,and effectively restrain the aforementioned affect, fast track the instruction signals. The chattering phenomenon is well overcome. The new controller is applied to the control method of hypersonic flight vehicle slow loop and fast loop controller design, the effectiveness is verified by simulation.Based on the linear model of hypersonic vehicle longitudinal input/output, the hierarchical sliding mode control method and nonlinear disturbance observer are adopted in view of the system uncertainty and actuator with a dead zone nonlinear problem. A hierarchical sliding mode control method with disturbance compensation was designed,realized the speed and the stability of the high speed tracking, and ensured the rapidity and robustness of the control system.