Safety Assessment Method And Design Optimization Of Rendezvous Trajectory In View Of Early Warning Threshold

With the development of space exploration, the requirement of autonomy forrendezvous and docking (RVD) technology is needed and the safety of the RVD isworth more attention. This dissertation studies the safety assessment method and thedesign optimization of passive safety trajectory. The main results achieved in thisdissertation are summarized as follows.The safety assessment method for rendezvous trajectory in view of earlywarning threshold is proposed.1) Based on false dismissal probability theory, theearly warning threshold is presented, and the calculation methods are provided.2) Thesafety assessment method for rendezvous trajectory in view of early warning thresholdis proposed, according to3ellipsoid and collision probability theory. and theircharacteristics are analyzed.The design approach for safety-optimal rendezvous trajectory is proposed,and its characte ristics are analyzed.1) An optimization model for the safety-optimalimpulsive linear rendezvous is formulated and the optimization algorithm is introduced.2) Several cases involving different rendezvous directions and different number ofimpulses are designed and optimized, and the characteristics and the engineeringapplication value of the safety-optimal approach trajectory are analyzed using theoptimization results.The optimization models and algorithms for designing multiple-objectiverendezvous trajectory including objective of safety are proposed.1) Thethree-objective optimization linear models including the minimum characteristicvelocity, the minimum transfer time, and the minimum safety performance index areformulated. The optimization abilities of non-dominated sorting genetic algorithm(NSGA2) and strength Pareto evolutionary algorithm (SPEA2) for this problem arecompared.2) The tradeoffs between the whole performance indexes of a rendezvoustrajectory are demonstrated, and the influences of rendezvous directions and number ofimpulses on the optimization results are illustrated.The Rendezvous Trajectory Safety Assessment Software is developed.According to the object-oriented methodology, the rendezvous trajectory safetyassessment software which aims at engineering is developed. The software coding bystandard C++programming language, has ability to analyse the safety of rendezvoustrajectory, and report relative state.This dissertation has some theoretical significance in developing the safetyassessment method and optimization for rendezvous trajectory. The proposedapproaches could be used for on-orbit rendezvous safety performance analysis, whichhave high engineering application value.