Research On The Preview Control Of Hypersonic Vehicles

With the continuous progress of modern military science and technology,hypersonic vehicles technology have become a more and more popular research field in the world.The stability of the control system was the key to the safe flight of the aircraft.The hypersonic vehicles have strong coupling,the strong nonlinearity and fast time-varying aerodynamic characteristics.The traditional control method only designs the controller according to the current flight reference information,and its system appears the output delay phenomenon.However,within certain flight ranges,some of its future external interference and target information can be previewed in advance.Therefore,how to effectively use the known future information to design the controller,so that its aircraft can be stable flight is the current priority.The main content is as follows:1.Firstly,according to Newton's Second Law and Momentum Moment Theorem,the motion equations of hypersonic vehicles are established.Secondly,the longitudinal model of hypersonic vehicles are obtained under certain assumptions.Finally,based on the linear principle of small disturbance,the linear model of hypersonic vehicles at the balance point is established,which lays the foundation for the subsequent controller design.2.Aiming at the control problem of hypersonic vehicles,an optimal preview controller with feed forward compensation function is designed.Based on the linear model of small disturbance,firstly,the extended error system is constructed by using the known future altitude information,velocity information and future disturbance information of the hypersonic vehicles.Secondly,based on the optimal adjustment method,the optimal preview controller is obtained.Finally,the longitudinal model of the hypersonic vehicles are taken as the simulation object,and the equilibrium point was taken as the initial condition to simulate and verify,the comparison of the optimal controller shows the superiority of the controller.3.Aiming at the control problem of hypersonic vehicles,an information fusion preview controller is designed based on the information fusion estimation theory.Based on the linear model of small disturbance,firstly,the optimal fusion filtering of the state sequence in the inverse time direction is used to obtain the information fusion preview control law of the hypersonic vehicles at the time.Secondly,for some states that are not easy to be measured directly during the flight of the hypersonic vehicles,the state observer is designed.Finally,the longitudinal model of the hypersonic vehicles is taken as the simulation object,and the equilibrium point was taken as the initial condition to verify the simulation,and the superiority of the information fusion preview control method was shown by comparing with the optimal preview control method.4.Aiming at the constraint conditions that need to be met during the flight of hypersonic vehicles and combining the advantages of predictive control and preview control methods,a preview predictive controller is designed.Firstly,the feed forward preview compensator is designed by using the known future flight altitude and velocity information and the known interference information of the aircraft.Secondly,the predictive controller is designed by using the predictive control method.Finally,the longitudinal model of the hypersonic vehicle is taken as the simulation object,the balance point is taken as the starting condition to carry out the simulation verification,through the comparison with the predictive control method,and the prediction is shown the preview predictive control method can improve the dynamic response and tracking accuracy of the system.