Research On Maneuvering Control For Hypersonic Vehicle

The air-breathing hypersonic vehicle has shown remarkable dual-use value because of its characteristics of continuous high-speed flight in adjacent space and has become the most important issue of adjacent space flight technology at present.In the meantime,the flight environment of adjacent space and new configuration of the vehicle make new characteristics and challenges to the control of the air-breathing hypersonic vehicle,especially in maneuvering phase.These challenges mainly include the large variation of dynamic coefficients,the ‘decoupling'of flight trajectory and attitude,the inaccurate aircraft model,constraints on attitude and angular velocity caused by the requirements of the scramjet working stably.These challenges make the control system to be stable,rapid,robust and state constrained.Taking the maneuvering flight issue of the air-breathing hypersonic vehicle as the core,this paper studies the variable parameter problem,the limitations of states,the ‘decoupling' of flight trajectory and attitude and the problem of model inaccuracy in a climbing phase of the flight.Through a set of robust adaptive state constrained control system design,it realizes the maneuvering control stable,fast and robust,without violating state constraints.This paper mainly focuses on the following issues:1.In order to make the dynamic behavior of the maneuvering meet the constraints of the working conditions of the scramjet,a command governor is designed and utilized.Through a specific designing work,the command governor can realize receding horizon optimization of the commands,making the flight states meet all the constraints without degrading the control quality.The status of the vehicle can reach the boundary quickly without overshoot,and running along the boundary.This unique characteristic is helpful for releasing the ‘decoupling'of flight trajectory and attitude,and improve the rapidity of the maneuvering.2.Considering the inaccuracy of the flight model,a robust adaptive controller is developed based on the previous work.This method using the constrained status of the nominal system as the reference status,the status of the actual system with parametric inaccuracy can be adjusted to approach the reference by a robust adaptive controller.The error between two systems can be reduced,so as to the spreading of the status of actual systems.The purpose of this method is to make the actual system with parametric inaccuracy imitates the behavior of the reference system so that the actual system can meet the constraints and reduce the status spreading.3.A polytopic flight model based on tensor product is established considering the large scaled time-varying parameters of the model,which caused by the change of aircraft flight environment and the changing aerodynamic characteristics.According to the polytopic vertex systems and convex decomposition coefficients,the aircraft model can be expressed as a linear parameter varying system with affine parameter dependent on adjusting parameters.This type of LPV model has advantages including good accuracy,low computing complexity,and polyhedral.This work is the foundation for the following flight controller design.4.The weight functions of the polytopic model of the aircraft are regarded as members of the Takagi-Sugeno fuzzy model,and the variable gain controllers of the aircraft are designed based on the principle of parallel distribution compensation framework so that the controlled systems can satisfy the asymptotic stability within the flight envelope.This work solves the flight control problem of the time-varying system.The results are used as the reference systems to the following robust adaptive constrained LPV control system.5.Finally,a robust adaptive constrained control method is proposed to the time-varying linear parameter varying system and the state bounded stability is proved.Considering the large variation of dynamic coefficients,the ‘decoupling' of flight trajectory and attitude,the inaccuracy of aircraft model and state constraints,this method systematically solves these problems.The working process is as follows: according to the flight parameters of the flight,the reference system is updated in real time,the optimized command can be generated by the command governor,and the actual plant's dynamic behavior is modified by the robust adaptive controller,which finally makes the actual system respond smoothly,quickly and satisfying state constraints,even the system is time-varying,nonlinear with parametric uncertainties.The numerical simulation results show the effectiveness of this method.In conclusion,this paper designs a control method based on the difficulties encountered by the air-breathing hypersonic vehicle in maneuvering phase.This method has stability,rapidity,robustness and takes into account the state constraints satisfying requirements for time-varying nonlinear systems with parametric inaccuracy,which is suitable for air-breathing hypersonic vehicle maneuvering flight control.The simulation results show that this method meet all the control objects in maneuvering phase of the vehicle,the closed loop system is stable,rapid,robust and state constrained.