Maneuver Orbit Design And Optimisation Based On Bézier Curve And Displaced Orbit

With the application of electric propulsion technology and the development of allelectric and solar sail spacecraft,the continuous thrust orbit has become more and more widely used in space missions.The two key problems of continuous thrust maneuvering are orbital design and orbit optimization.For a continuous thrust orbit design problem,the forward method is difficult to meet the orbital state constraints,while the backward method is not satisfactory because the transfer orbit equation is too limited.For the orbit optimization problem,the commonly used direct method has a large amount of calculation,and the initial value of the indirect method is difficult to guess.The intelligent optimization algorithm still has many problems.In this paper,the in-depth research on the design and optimization of continuous thrust orbit based on the backward method is carried out.The main contents and innovations of the paper are as follows:To solve the problems of low efficiency and local optimum of differential evolution algorithm and the existing improved algorithms,the dual adaptive factors related to evolution generations and current index functions are designed to improve the optimisation efficiency and an independent random mutant factor is introduced into each generations to improve the problem of local optimum.A dual adaptive differential evolution algorithm with an independent random mutant factor SA-DE-RM is obtained.The algorithm performs much better than other algorithms in the simulations of eight test functions,and the optimality and stability are both improved.This thesis further uses the SADE-RM algorithm to solve several typical orbit and maneuver optimisation problems and gets better results,including Lambert transfer optimisation,multi-point observation maneuver optimisation and multi-target revisiting orbit optimisation problems.For the problem of planar maneuver orbit design,this paper proposes a planar maneuver orbit design method based on Bézier curve.The method combines the Bézier curve equation with the orbital shape equations,uses the obtained composite function as the transfer orbit equation to describe the maneuver orbit,obtains the feasible maneuver orbit family through the constraint condition,and gives the specific optimisation variable through the control point design.Through the calculation of the accumulate velocity pulse,the optimal index function is given and the SA-DE-RM algorithm is used to complete the orbit optimisation and the optimal maneuver orbit is given.The design and simulation of single 5th-order Bézier curve design method and double 6th-order Bézier curve design method are completed,and a segmented improvement is adopted to reduce the peak value of the thrust and the fuel consumption is further reduced as well.For the spatial maneuver orbit design problem,this paper decomposes the spatial orbit maneuver into two parts: the shape maneuver and the orbit elevation angle maneuver,and uses the composite function of the Bézier curve orbit design method to complete the design of in-plane shape maneuvers and out-of-plane elevation maneuvers.Through the addition of the maximum thrust peak constraint in the optimisation process,the peak value of the maximum thrust is constrained within a limited range,and the optimal orbit of the spatial maneuver orbit is achieved.To solve the problem of maneuver between two orbit planes,a maneuver method based on the displaced orbit is proposed.This method uses the displaced orbit as transfer orbit and completes maneuver tasks by jointing of orbits.This method can finish fast non-planar maneuver task in which the phase angle is adjusted synchronously with the orbit plane,and the thrust of the entire process is constant,which is easier to implement.In this paper,the maneuver cost and stability are analyzed.A pulsed realization method is proposed in consideration of the engineering realization and replaces the displaced orbit by multi-segment splicing.The continuous thrust maneuver task is converted into a multi-pulse form,which does not require the high thrust of single impulse method,and also does not require the engine to continue working for such a long time as displaced method,and can accomplish the large-scale,non-planar and rapid maneuver tasks of the spacecraft with limited propulsion system.