The Transfer Trajectory Design And Optimization For Low-thrust Spacecraft

The transfer methods of spacecraft are generally divided into pulse transfer method and low-thrust transfer method.Pulse transfer has characteristics of high thrust,high fuel mass consumption and high transfer cost.Low-thrust propulsion system is a popular technology in recent years,which has characteristics of higher specific impulse and lower transfer cost than pulse transfer method.Using the shape-based method,the 3-order Fourier series method,the finite Fourier series method and the indirect method,the multi-revolution transfer problem,the multi-revolution transfer problem with constraints,the optimal transfer problem are studied in this paper.The simulation results verify the effectiveness of these algorithms.Through the description of the current researches for deep space exploration,the development of space exploration in the world are introduced.In this paper,low-thrust transfer method is selected,then initial design and optimization for spacecraft transfer trajectory is introduced,also important dynamics models and problem of transfer trajectory design are described,which lay foundation for next studies.Shaped-based initial design models of transfer trajectory are carried out,and multirevolution transfer problem under tangent low-thrust is studied.The inverse fifth-order polynomial method and the modified inverse fifth-order polynomial shape-based method are selected for the initial design,and the increment of velocity and the maximum tangent low-thrust acceleration under different transfer revolutions are compared.The multi-revolution transfer problem with constraints under tangent low-thrust based on 3-order Fourier series is described.By using the sine and cosine periodic terms of 3-order Fourier series,the initial design of multi-revolution trajectory for spacecraft transfer is proposed,transfer trajectory curves and simulation results based on 3-order Fourier series method and 3-order Fourier series with cosine term method are carried out.The transfer trajectory is modeled by the finite Fourier series and is optimized.Without assuming that spacecraft transfer process is under tangent low-thrust,finite Fourier series method is applied to solve multi-revolution transfer problem with constraints.By solving the Hamilton two-point boundary value problem with introducing co-variate variables,the optimal control of multi-revolution transfer trajectory for spacecraft under lowthrust is obtained.