Abstract:

The co-evolutionary algorithm is used to simplify the complex double boundary optimal planning problems into the searching of Nash equilibrium in three dimensional space pursuitevasion of two spacecraft within a fixed time interval. This method provides an optimal antagonistic strategy and its solution for the pursuer and evader spacecraft. To reduce the computing time while maintaining computational accuracy, the strategy model is simplified with spacecraft thruster directional angles approached using the B-spline basis function as control variables. The relative terminal distance of the two spacecraft, which are both considered to below continuous thrust systems is defined as a pay off function which the evader expects to be maximum while the pursuer expects to be minimum. A shared fitness function is therefore established. This study also improves the design of compact genetic operators which enhance the space searching ability of the algorithm. The use of the elitism strategy in the algorithm enables a faster converging rate. Simulation results show that the optimal control strategy and corresponding pursuit and evasion trajectories for both spacecraft are obtained by the proposed method, thus the ability of the algorithm in solving two spacecraft pursuitevasion problems is demonstrated.