Trajectory Planning For Chaser Satellite Close Non-Cooperative Target Spacecraft

With the increasing number of space service missions in orbit,new requirements have been put forward for the development of space autonomous rendezvous technology.For the stage of space autonomous rendezvous and proximity of non-cooperative targets,the target cannot actively cooperate with the service star to complete the rendezvous task,which requires the service star to consider more constraints.Therefore,it is necessary to choose an appropriate trajectory planning method to enable the service star to complete the rendezvous task quickly and accurately.This paper will take the close proximity of the service star to the non-cooperative target as the research background,and according to the characteristics of the target,study the planning problem of the service star in the trajectory,mainly including the following contents:Aiming at the problem that the service satellite is close to the non-cooperative target,the satellite trajectory planning model is established,which includes satellite kinematics,dynamics,view Angle constraints,obstacle avoidance constraints,thrust amplitude constraints,terminal rendezvous constraints and other path constraints.Aiming at the problem of energy optimal trajectory planning for a service star approaching a non-cooperative target without spin,the non-convex equation of the model is linearized by Taylor expansion,and the convex trajectory planning model is obtained.And the model is equidistant dispersed to obtain discrete convex model,using convex optimization solver,combined with the iterative sequence of ideas for problem for iterative approximation.Numerical simulation results show that this method can quickly solve an energy optimal trajectory satisfying the constraints.Aiming at the problem of terminal time free spin-free non-cooperative target approach trajectory planning,the time scaling factor is introduced to normalize the problem,and the normalized optimization model is obtained.To solve the problem of artificial infeasibility caused by the introduction of time scaling factor,virtual control variables are introduced to make up the errors between models in the early iteration.The model error is gradually reduced by iteration so that the solution of the normalized model approximates to that of the original problem.The solution time and the optimal time are analyzed according to the initial value of time guess.The inverse dynamics method is used to solve the problem for non-cooperative targets with spin.Firstly,the trajectory of the model is given polynomial value in time domain,and the performance index is converted into polynomial expression in time domain according to inverse dynamics method,thus the trajectory planning problem is transformed into nonlinear programming problem.Select the appropriate polynomial order,reduce the number of variables in the optimization,and use IPOPT solver to solve.Numerical simulation results show that the inverse dynamics method can solve an energy optimal trajectory for the target spin problem under multiple constraints.