Research On Tracking Control Methods Of Hypersonic Vehicle

The hypersonic vehicles has significant military and civilian value,which has become the focus of the research of near space vehicle for domestic and foreign.The unique integrated design and complex flight environment can lead to complicated dynamic characteristics containing fast time varying,strong coupling,nonlinearity and uncertainty in the corresponding models.Therefore,it is the one of the research hotspot to design the control schemes satisfying the constraints above.This paper research the tracking control problem of hypersonic vehicle subject to model parameter uncertainties,external disturbance,input constraint,actuator fault,tracking error constraints and state constraints.The main contents are as follows.Firstly,the robust tracking problem of hypersonic vehicle subject to external disturbances and model parameter uncertainties is studied and analyzed.Focusing on multivariable second-order system model of hypersonic vehicle,the back-stepping law and the adaptive terminal sliding mode law are proposed by using the back-stepping method and the terminal sliding mode theory combined with the adaptive control technique.In order to further enhance the robustness of the control system and reduce the control gain of the system,base on non-singular terminal sliding mode control theory,the terminal sliding mode robust controller is proposed by using non-homogeneous disturbance observer to estimate the external disturbances of the system,which can improve the dynamic performance and steady-state performance of the system.Secondly,the robust tracking control problem of hypersonic vehicle with model parameter uncertainties,external disturbance and input constraint is studied and analyzed.The anti-saturation adaptive robust tracking control strategy and anti-saturation adaptive integral sliding mode control strategy for multivariable second-order system of hypersonic vehicle are given based on saturation function,auxiliary systems and differential mean value theorem.In order to improve the anti-interference performance of system,the non-homogeneous disturbance observer is used to estimate the external disturbance.And based on the terminal sliding mode control method,the anti-saturation sliding mode controller is proposed for the multivariable second-order system of the hypersonic vehicle by using differential mean value theorem,whose singularity problem is solved by introducing the new saturation function.All of the proposed controllers not only satisfy the requirements of the physical limitation of the actuator,but also can ensure the performance of hypersonic vehicle tracking.Thirdly,the track control problem of hypersonic vehicle in the presence of model parameter uncertainties,external disturbance and actuator fault is studied and analyzed.Based on passive fault-tolerant control method,the fault-tolerant control strategy of nonlinear function and terminal sliding mode fault-tolerant control strategy for multivariable second order system with actuator failure are given by using nonlinear function and terminal sliding mode control theory.In order to deal with input constrain problem,based on terminal sliding mode control theory and adaptive technology,two anti-saturation terminal sliding mode fault tolerant controllers are proposed for multivariable second-order system with actuator failure and input constrain by introducing the saturation factor and auxiliary system.And the actuator fault information is estimated online by an adaptive algorithm without fault information in practice.Via the proposed controllers,the physical requirements of the actuator can be met,also the strong fault-tolerant capacity can be possessed.Finally,the tracking control strategy of hypersonic vehicle under model parameter uncertainties,external disturbance,actuator fault,output constraint and state constraint is studied and analyzed.An adaptive terminal sliding mode tracking controller under output tracking error constraint is proposed by using performance index of tracking error,terminal sliding mode control theory and adaptive control technology,which can guarantee the tracking error can converge along the expected error performance function.In order to slove state constraint problem,the adaptive dynamic surface controller of velocity and the adaptive dynamic surface controller of altitude are proposed for the velocity subsystem and the altitude subsystem respectively by using the tangent barrier Lyapunov function and adaptive technology.All of the proposed control scheme can not only satisfy the requirements of tracking performance,but also can meet the constraint condition in the flight process.