Finite-time Backstepping Control Method Of Hypersonic Vehicle

Hypersonic vehicles(HFV),or supersonic aircraft with a flight speed greater than 5 Ma,have high research value both in military and civilian applications.Due to its rapidity,high maneuverability and strong penetration capability,it is a hot field in which military powers around the world are actively studying.Because hypersonic vehicles have the characteristics of fast time-varying,highly nonlinear,strong coupling,uncertainty,elastic vibration,etc.,designing a flight control system is a very challenging task.The application of the finite-time stability theory based on Backstepping in the tracking control problem is studied from the aspects of elastic vibration,parameter uncertainty,external disturbance and input limitation of the hypersonic vehicle,and finally achieves the goal of stable tracking of hypersonic vehicles.First,based on the Newton's Euler equation,a pure rigid body model in the longitudinal direction of the aircraft is established.The fuselage is regarded as a uniform free-form Euler beam at both ends,and the elastic vibration equation of the aircraft is derived.When considering the coupling between elasticity and rigidity,according to the different forms of influence of the action,the analysis and modeling are carried out separately,and the nonlinear model of HFV is processed.Summarizing the above analysis results,the comprehensive dynamic equation of the control-oriented HFV is obtained.Secondly,through two reasonable assumptions,the rigid body m odel of the aircraft is simplified into a form of strict feedback,and is divided into two subsystems of speed and height.The finite time Backstepping controller is designed separately,and the command filter is used to solve the virtual in the controller design process.Derivatives replace complex analytical derivatives.Based on the Lyapunov stability theory,the finite-time stability criterion is used to verify that the designed controller can converge the state of the system to a small neighborhood of the system equilibrium point within a finite time.The HFV achieves finite time stable tracking of reference instructions and is verified by simulation.Third,using the effects of elastic vibration,model parameter uncertainty and external disturbance as aggregate interference,a linear extended state observer(LESO)is designed to observe and estimate interference.To achieve interference compensation to the controller.Using the same stability criteria,verify the stability of the modified control system and verify it by simulation.Finally,considering the constraints of the control input,the auxiliary system is designed to compensate the influence of input saturation on the stability of the system,and the auxiliary system state is introduced into the controller design.The designed controller can not only meet the physical limitation requirements of the actuator.And the performance of the hypersonic aircraft tracking control is guaranteed.