行星动力下降多约束最优反馈制导方法

Multi-constraint Optimal Feedback Guidance for Planetary Powered Descent

为实现行星定点着陆,针对E制导和零控位移偏差/零控速度偏差(ZEM/ZEV)制导的不足,提出多约束下动力下降最优反馈制导方法。首先,在分析E制导性质的基础上,提出制导时长初值的高效选取方法和基于预测校正的优化方法,经少量迭代实现在推力范围受限且连续变推力约束下推进剂消耗接近最优。接着,提出基于碰撞规避时长和推力优化分配律的地平碰撞规避方法,并在此基础上利用坐标系旋转,给出满足下滑角约束的碰撞规避方法,显著提高碰撞规避能力和着陆点可见性。之后,提出匀速转动制导和基于预测校正的组合制导参数规划方法,使制导终端扩充满足加速度约束。最后,数学仿真表明新方法有效,多约束适应性强,计算量相对小,适合工程应用。

For planetary pinpoint landing,an optimal feedback guidance of powered descent with multiple constraints is presented to overcome the limitations of E-guidance and zero-effort-miss/zero-effort-velocity(ZEM/ZEV)guidance.Firstly,based on the analysis of the properties of E-guidance,an efficient method for the initial guess of time-to-go and an optimization method based on predictor-corrector is proposed.With a few iterations,the fuel consumption is near optimal with the thrust magnitude and continuity constraint.Then,a horizon collision avoidance method based on collision-avoidance-time and optimized thrust distribution law is proposed.On this basis,a collision avoidance method meeting the glide-slope constraint is given by using coordinate rotation,which significantly improves the collision avoidance capability and the landing site visibility.After that,the uniform rotation guidance and the integrated guidance parameter planning method based on predictor-corrector is proposed,so that the guidance terminal states meet the acceleration constraint.Finally,the mathematical simulation shows that the new method is effective,has strong adaptability to multiple constraints,and requires relatively little computation,which is suitable for engineering applications.