连续小推力航天器轨道交会问题的制导律设计

Guidance law of spacecraft for continuous low-thrusts orbital rendezvous problem

摘要:

使用高比冲的小推力推进系统为执行机构,设计空间交会问题的燃料最优时间连续制导律.首先给出轨道交会问题的数学模型,并给出最优控制问题的目标函数和约束条件;然后利用直接法将控制变量离散化,通过参数寻优得到对应燃料最优的控制变量参数和转移时间常数;最后针对点火时刻误差问题,分析了实际轨迹与名义最优轨迹的偏差,并利用微分代数工具求取部分控制变量的修正值,以保证航天器满足轨道交会的终端位置约束.

Abstract:

The hypothesis of pulse thrust cannot be always satisfied for the short-range stage of space rendezvous.In this article,High isp low-thrust is applied as actuators to solve the fuel optimal control problem of spacecraft rendezvous condition.First,we gave the mathematical models of the orbital rendezvous problem,the performance index function and constraints equations are also presented.Then,we used the direct method to discrete the control variables,though parameter optimization algrithm to get the optimal control variable and rendezvous time constants.Finally,aimed at the fire time deviation,we analyzed the error between the actual trajectory and the nominal trajectory,and obtained the correction value of control variables.Using this correction values,the spacecraft can satisfy the final position constraints and avoid the complex optimization computing process.