Research On The Symplectic Approach For Attitude Optimal Control Of Spacecraft Maneuver

Large-scale space missions require high-precision and high-efficiency calculation of their orbits and attitudes,and due to its strong coupling characteristics of their dynamic equations and the existence of spatial disturbance forces,which increase the difficulty of their attitude controls.The robustness of the attitude control system have been required very high.Constrained by the high cost of aerospace engineering,a lot of research focus on how to plan the optimal control scheme during the spacecraft attitude maneuver control process,so that the spacecraft can not only reach the desired position,but also decrease the energy consumption and prolong its on-board service time.This dissertation takes the spacecraft attitude maneuvering as its research background.symplectic pseudospectral algorithm,which possess an efficient and high precision solving ability,is established to solve the optimal control problem in the attitude maneuver process.Given the optimal control scheme for attitude regulation and the optimal path is planned.At last,the optimal trajectory tracking is researched by giving the synovial variable structure control law.Firstly,the background of the spacecraft’s attitude maneuver control and the research status of the optimal control problem are introduced.stated out the research significance and actual engineering application of the optimal control of the attitude maneuver and the research work of this paper.Then by using the orthogonal projection method,the explicit formula of the quaternion parameters are used to establish the motion model of the spacecraft.The simulation results are displayed by using the implicit Runge-Kutta method and show the superiority of this method compared with the conventional integration method.Next,the construction process of the symplectic pseudospectral algorithm is given by means of the dual variation principle.The fourth class of generating function is used to transform the optimal control problem into the boundary value problem;then the Legendre orthogonal collocation is used to interpolate the state variable and the covariate variable and the control variable,and the constraints of the original differential equation is converted into a series of discrete points algebraic equation.By using the quasi-linearization method,the Jacobi matrix of the system which has a symplectic matrix with sparse symmetry is obtained,and the integral operation is converted into algebraic sum,which improves the computational efficiency and embodies the characteristics of the algorithm.The numerical results prove that the proposed method has the advantages of high efficiency and high accuracy,and the effectiveness of the algorithm.At last,the optimal control problems of spacecraft attitude maneuver is giving.The symplectic pseudospectral discrete method is used to deal with nonlinear coupled motion equations of spacecraft.In order to meet the constraint precision requirements,by using the hp adaptive mesh refinement technology to optimize the distribution between the number of divided segments and the number of selected discrete points,which accelerates the convergence speed and improves the efficiency of the algorithm.Through the example simulation,the optimal control scheme of the spacecraft is given and the feasibility of the approach is analyzed.and the influence of the space disturbance torque is comprehensively considered.The sliding model controller is designed to obtain correction control law and to realize the real-time tracking of the optimal orbit of the spacecraft maneuver.