Maneuver Path Plan For On-orbit Assembly

Considering the limit of nowadays launch vehicle technology,the large-scale spacecraft cannot be deployed into the orbit at one time.Thus on-orbit assembly has become a key trend of the development of space technologies.Many space missions have urgent requirement for on-orbit assembly technologies such as space structure construction,satellite refueling,repairing and maintaining.Previous deployment for large scale spacecraft was usually extended by rendezvous and docking,however,it cannot be easily built by maneuver only.So auxiliary operators,such as space manipulator and space robot will provide more options for on-orbit assembly.The path plan for the background demonstrated above is now one of the new hotspot in the field of on-orbit service.In this paper,the maneuver process of on-orbit assembly is mainly studied,which is divided into approaching phase and attitude maneuver phase.The research can be introduced as follows:First,the relative motion modeling of on-orbit assembly is introduced.This chapter introduces two common relative motion model based on the two-body problem including the C-W equation and the T-H equation,and the first-order analytic solution of them,which bring out an exact and effective model for orbit maneuver.Besides,this chapter also briefly introduces the rudiments related to attitude dynamics,covering attitude description,the transformation between different attitude parameters types,and the attitude motion and dynamic equations.This chapter mainly presents the groundwork of the next chapters.Second,from dynamic perspective,this chapter presents the research of the relative motion trajectory design of the assembly satellite.By analyzing the characters of C-W equations,four types of trajectory were introduced and the initial conditions respectively.In addition,this chapter presents the guidance laws for the assembly approaching maneuver based on double-pulse maneuver.The guidance laws are derived from the analytic solution of the C-W equations and T-H equations,and provide the dynamic model for the following optimal algorithm.Third,this chapter presents a trajectory plan for on-orbit assembly based on an improved genetic algorithm through series of researches such as relative motion modeling,operation dynamic environment modeling,and genetic algorithm improvement in the simultaneous optimization of time and position accuracy.The simulation illustrates the algorithm is able to satisfy the accuracy requirement which is proved effective and stable.Fourth,this chapter presents a method of quick attitude maneuver for assembly auxiliary operator in the end of the orbit maneuver which based on Bang-Bang theory.The attitude maneuver strategy is designed by planning the angular acceleration of one inertia axis including the planning function and interaction time,and proved valid by simulation.This paper simplifies the process of on-orbit assembly.The research solves the main orbit maneuver problem and attitude maneuver problem respectively.The model and algorithm presented in this paper are verified by simulation.