Study On Navigation And Control For Proximity Operations Space Non-cooperative Target

To meet the requirements of emerging space missions in space service,active debris removal,space attack and defense,and achieve spacecraft assembly,maintenance,and replenishment and capture operations,the focus of spacecraft close orbit operation technology has changed from cooperative target to non-cooperative target based on space rendezvous and docking technology,and developed from ground tracking and control and man-in-loop control to autonomous operation.The notable features of target spacecraft include without effective cooperative identification and exchange information and even with unstable attitude,unknown shape and mass characteristic parameters,so new navigation and control technology is necessary to be developed for close orbit operating space non-cooperative target.In this paper,the navigation and control problem for close orbit operating space-non-cooperative with unknown physical features and uncertain movement state is studied,and the physical parameter estimation and attitude stabilization of the combination spacecraft is discussed.First,the relative state dynamics of the spacecraft with respect to the target are established.The relative state variables are uniformly expressed in the tracking spacecraft coordinate system,which properly dealt with the control command coupling and the control input coupling problems.Then,a relative navigation and parameter estimation algorithm based on stereo vision is designed for close approaching.A set of parameters are used to describe the center-of-mass position and orientation of the principal axis of the non-cooperative space target,and the parameters describing the target characteristics are estimated independently without need much more priori information.Next,the approaching control law for close approaching is designed.Uncertainties of the target including mass parameters,environmental perturbations and avoidance maneuvers are processed uniformly.Compound uncertainties are estimated and compensated.The attitude synchronization and position tracking relative to the target spacecraft are achieved.Finally,after the capture,the physical parameters of the combination spacecraft are estimated,and its attitude is stabilized by a designed active control law.