Study On Fast Trajectory Planning And Tracking Guidance For Vehicles With Combined Cycle Engines

A vehicle with a combined cycle engine is among the most promising development directions in aerospace engineering.The vehicle can adapt to different flight environments and have a wide speed range.Thus,it can meet diversified requirements.The dynamic characteristic of the vehicle is complex,which brings new challenges to the trajectory planning and guidance.In this study,the fast trajectory planning and tracking guidance method in ascent phase and cruise phase of the vehicle with a turbine based combined cycle engine is studied.The main work is as follows:(1)The motion model,dynamic system model and general trajectory optimization of the vehicle with a combined cycle engine are established.A trajectory planning method based on the integral sectional collocation method is studied.Based on a class of Birkhoff polynomials,the discretization method of dynamic constraints is derived,and the general solution flow of integral sectional collocation method is given.The relationship between the integral collocation method and the classical pseudospectral method is studied.The equivalence of the two methods for the constraint transformation of differential equations is proved,and the difference between them in numerical calculation is compared.(2)The trajectory planning method of the ascent phase for the vehicle with a combined cycle engine is studied.A feasible trajectory design method based on rapid generation of state profile is proposed.In view of the dynamic characteristics of aircraft,the corresponding control solution method is deduced.Considering the fuel consumption index,the integral sectional collocation method is used to optimize the trajectory of the ascent phase.The effectiveness and performance of the trajectory optimization method are verified by simulation.(3)The ascent guidance method based on the online trajectory planning is studied.The reference trajectory is updated by hierarchical receding horizon optimization.The feedback control is derived from active disturbance rejection trajectory tracking,and the correction of the calculation model is realized based on the online system identification method.To meet the fast computing requirements of online trajectory planning,a receding horizon updating strategy of discrete solution and mesh is proposed to improve the efficiency of integral sectional collocation method.The extended state observer of Multiple Input Multiple Output(MIMO)system is designed,and the feedback correction method of guidance command is derived based on dynamic compensation linearization.Simulation results show the effectiveness and robustness of the guidance method.(4)The trajectory planning and guidance method of cruise phase are studied.Considering the no fly zone,the avoidance strategy based on waypoint and the cruise trajectory optimization method based on reduced order motion equation are proposed respectively.The relative motion equation between the vehicle and waypoint is derived,and the calculation method of control is derived based on steady-state cruise conditions.The integral sectional collocation method is applied to the trajectory optimization of cruise phase under multiple constraints.Simulation results show the effectiveness of the two methods.Finally,the active disturbance rejection trajectory tracking method is applied to cruise trajectory tracking,and the simulation results show the effectiveness of the guidance method.Considering the mission requirements and the existing technology,the study focuses on feasible trajectory design,trajectory optimization and reference trajectory tracking.It can provide a reference for the research of trajectory planning and guidance technology of the vehicle with a combined cycle engine.