月球精确定点软着陆轨道设计及初始点选取

研究了一种应用参数化控制求解月球探测器精确定点软着陆最优控制问题的方法.首先用约束变换技术将不等式约束进行了近似处理,而后利用若干个分段的常数去逼近最优解,再根据强化技术通过时间轴上的变换,将每一段参数的持续时间转变为一组新的参数,于是最优控制问题被转化为一系列参数优化问题.最后应用经典的参数优化方法即可求得最优控制函数的一个近似解,通过增加参数个数,重复优化得到逼近连续最优解的参数化解.同时在优化过程中考虑了制动初始点的选取对结果的影响.仿真结果表明了所提设计方法是简单、有效的.

Orbit Design of Lunar Precise Fixed-point Soft Landing and Selection of Initial Point

A method of applying parametric control and enhancing technique in order to solve optimal control problem of lunar probe precise Fixed-paint soft landing is studied. Firstly the inequality constraint is approximated by using constraint transformation technique. Secondly the piece-wise constant value is used to approach the optimal solution. Based on enhancing technique, each period of duration of parameters is transformed into a term of new pin, meters. So the optimal control problem is transformed into the parameter selection problem which can be solved by the classical parameter optimization method. By means of increasing the number of parameters and the iteration of optimization, the parametric solution which approaches the continuous optimal solution is derived. In the optimization process, the selection of the initial point is also studied. The result of the simulation demonstrates the proposed design scheme is simple and effective.