Accessibility Analysis And Guidance Control Strategy Research For Spacecraft Proximity Operation

Affected by the limited design life and complex space environment,on-orbit spacecraft will face the risk of degradation,failure,or even abandonment.This not only causes significant economic losses,but also poses a safety threat to the normally operating spacecraft.This paper considers the completion of rendezvous and near-field operations on a non-cooperative target that is in orbit failure.This type of spacecraft does not have attitude and orbit control and information interaction capabilities.It may be in a rolling motion state due to external disturbance torque.It is precisely because the target satellite may have irregular motion,it is very important to understand the inherent capabilities of this complex power system and design a stable guidance control strategy,because the performance of the service spacecraft and the quality of the completed mission are closely related to its effectiveness.According to the characteristics of the aforementioned task scenarios,this article mainly has the following contents:Aiming at the motion scene of the service spacecraft approaching a tumbling target spacecraft,the definition of the coordinate system for establishing the motion model in this scene is given.At the same time,in order to avoid the singular phenomenon caused by the large attitude angle during the satellite maneuver,improve the To solve the velocity,consider using the modified Rodrigues parameter(MRP)to express the attitude motion equation,and finally consider the coupling term to derive the relative pose motion model of the two spacecraft in the target rollover state.This paper discusses the concept of reachable sets and the methods of solving the existing reachable set problems,solves the problem of finding feasible initial conditions for intersection maneuvers,and gives different methods for visualizing the position set and pose set.Combining the reachability set problem with the optimal control problem,the Radau pseudo-spectrum method is selected to solve the optimal path planning problem.According to the difficulty of the problem,first consider the spin motion of the target spacecraft in a circular orbit,simplify the dynamic model of the intersection with the target spacecraft,and decompose the complex nonlinear system into a translation subsystem and a rotation subsystem.Independent research is carried out separately.Finally,the target spacecraft is considered to roll,and the reachability of a high-dimensional nonlinear dynamic system is discussed.Based on the reachability set analysis of the system above,it is determined whether maneuverability is feasible in a given time range.If feasible,the model predictive control framework is used to discuss the practical application of the problem,and a stable feedback control law is designed.First,the relative motion mathematical model is linearized and discretized,and the spacecraft is controlled by rolling optimization to solve the optimal control problem.Based on the actual situation,the collision constraints are considered to improve safety,and compared with the planned trajectory under optimal control to verify the effectiveness and safety of the control law.