Research On Online Trajectory Planning And Guidance Control For Aircraft

Guidance and control technology is the "nerve center" of aircraft,which plays a vital role in the completion of mission.With the development of aerospace technology,it is necessary for future aircraft to have high maneuverability,strong adaptability and high reliability,which puts forward new requirements for the advanced guidance and control technology.Specifically,the aircraft has a stronger real-time task processing capability,and can have a high-precision strike capability under larger disturbances;the vehicle can have fault adaptability and can have the ability to complete or partially complete tasks in case of failure;and the satellite can have a stronger attitude control capability to deal with other problems.The influence of the uncertainty of the jammer needs to be studied in the next generation of guidance and control.One of the basic characteristics of this guidance and control method is that it has on-line task processing capability and can implement trajectory planning,guidance and stability control online.In this paper,the pseudo-spectral method-based ascent trajectory optimization and guidance method is studied to solve the reconfigurable ability of the vehicle in the case of failure,and the convex optimization-based reentry trajectory optimization problem is studied,which has the ability of route planning and no-fly zone avoidance to improve the real-time task processing ability.A high-performance attitude control algorithm based on sliding-mode is proposed to adapt to the problem of satellite attitude affected by external disturbances and system uncertainties.Firstly,this paper describes the current background problems,then summarizes the research situation of advanced guidance and control at home and abroad,summarizes and analyses the research work of on-line trajectory optimization and reconfigurable guidance and control,and points out the direction for exploring effective technical approaches to solve the problems.Aiming at on-line trajectory optimization and guidance,the processing ability of real-time constraints is mainly studied.Therefore,direct collocation method is selected as the research method,i.e.pseudo-spectral method and convex optimization method are used to solve the problems of ascending and reentry stages respectively.Aiming at the influence of jammer uncertainties,a dynamic sliding mode control method is selected to solve the attitude stabilization problem in vacuum section.This paper focuses on the direct collocation method.Therefore,the non-linear programming problem is described in detail,especially the possible problems in the process of solving.Then,the convex optimization problem and its typical algorithm are introduced.The real problem of the on-line trajectory optimization is on-line optimal control problem.So,it summarizes the most important method to solve the optimal control problem and pick up a kind of Radau pseudo-spectral method.For online trajectory optimization,the most critical requirement is to ensure real-time and convergence.In order to improve the convergence and real-time performance of on-line trajectory optimization,the key technologies of pseudospectral method are improved,including full-state scale change technology,sparse Jacobian matrix with restrictions,adaptive mesh pseudospectral algorithm and improved technology,and the optimization and feasibility of the algorithm are also discussed.Verify analysis.Subsequently,the corresponding adaptive guidance method is studied mainly for the online trajectory optimization algorithm.Aiming at on-line real-time trajectory optimization algorithm,a kind of on-line real-time trajectory optimization guidance method is studied and designed.On the basis of on-line trajectory optimization,aiming at the current flight state and flight conditions,the on-line trajectory optimization technology is used to solve the problem of fault adaptability in the ascending flight process,and a large-scale carrier is used.The rocket is simulated.Taking the trajectory optimization and guidance method of reentry vehicle as the starting point,the convex optimization problem of reentry trajectory under given velocity and angle of attack profile is proposed.In order to deal with the problem of discretization caused by terminal time freedom,variable substitution is selected and generalized energy is used as integral independent variable,so that the problem of time freedom can be turned into one.The optimization problem is reduced to a fixed energy interval.Then,aiming at the optimization of reentry trajectory with the constraints of point of flight and no-fly zone,starting from the time domain,using the multi-segment sequential convex optimization method,the constraints of point of flight are transformed into the smoothing constraints of trajectories connected with each other,and the flight time of each period is normalized,and the terminal time of each period is introduced as the control variable.Through the linearization and discretization of trajectory,and convex processing of various constraints,the trajectory convex optimization problem is established and solved.After completing the design of trajectory and guidance,a dynamic sliding mode attitude stabilization control method with attitude angular rate and control constraints is studied.Compared with static sliding mode control,this method can provide a faster convergence rate of attitude stabilization system.At the same time,the method has a simple structure and can be used to control the attitude stabilization system.Under the conditions of external interference,angular rate constraints and other control constraints,it is guaranteed to have high stability.Finally,the research results and innovations of this paper are summarized and analyzed,and some difficulties of online trajectory optimization and guidance control methods are analyzed and summarized,especially the real-time and convergence solutions and engineering applicability problems.Suggestions for further research are put forward.