Orbit Optimization And Design Of Spacecraft Remote Rendezvous With Specific Thrust Direction

Spacecraft orbit optimization is one of the earliest applications of optimization theory in the aerospace field.Actually,the Spacecraft orbit optimization and design problems are equivalent to optimal control problems.The Pontryagin minimum principle and Bellman dynamic programming provide a solid theoretical foundation for solving optimal control problems.After this,scholars conduct more in-depth studies on the problem of spacecraft orbit optimization.In these studies,most of them are based on impulse thrust.In recent years,the research on orbital maneuvering of spacecraft under continuous thrust has attracted the attention of many scholars.In the traditional continuous thrust method,the direction of thrust is unconstrained and is considered to be freely variable which result in traditional continuous thrust method is difficult to be implemented in the real space field.Considering the factors that the thrust model is easy to be applied in the space field,this paper makes a study of spacecraft remote rendezvous on the basis of the thrust model with specific thrust direction.Firstly,the appropriate description methods are used to describe the motion state of the spacecraft according to different coordinate systems,the conversion relationship between different description methods is deduced,and the dynamic equations of different description methods are determined.The mechanical model of the thrust of the spacecraft is established,and mechanical model with specific thrust direction is compared with the continuous thrust model.The dimensionless processing of relevant parameters improves the accuracy of the calculation and the stability of the results.Secondly,according to different dynamic models and thrust models,the corresponding optimal control is determined by Pontryagin minimum principle.For the mechanical model with specific thrust direction,models of one-direction thrust and multi-directional thrust are analyzed and respective optimal control equations are obtained.In order to avoid the discontinuity in the optimal control equations,smoothing processing is applied which provides a theoretical foundation for the subsequent simulation and calculation.Thirdly,the required optimization algorithms for simulation are analyzed and selected.The advantages and disadvantages of the Quantum-behaved Particle Swarm Optimization algorithm and the Sequential Quadratic Programming algorithm are analyzed respectively and a scheme in which the two methods are used in tandem is proposed based on the advantages and disadvantages of the two optimization methods.This combination method enables the two optimization methods to maximize their advantages which improves the stability of the calculation and the accuracy of the results.Then,the continuous thrust model and the mechanical model with specific thrust direction are used to simulate the coplanar rendezvous and the no-coplanar rendezvous respectively.Based on the calculation results,the difference in fuel consumption between the two cases is analyzed and the relevant rules of the mechanical model with specific thrust direction are studied.Finally,the study results of this paper are summarized and the results show that,the mechanical model in the specific thrust direction not only succeeds in theory,but also its results are more easily applied in space operations compared with the continuous thrust model.