Lyapunov-Based Hazard Avoidance Control Method for Landing on Small Celestial Bodies
摘要: 针对姿轨耦合型探测器控制方法存在工程实现难、计算效率低的问题,提出一种基于Lyapunov函数的小天体自主软着陆障碍规避控制方法。首先,建立了小天体着陆过程姿态和轨道的动力学模型;其次,考虑探测器当前的势能与障碍地形对探测器的威胁选取Lyapunov函数,并根据Lyapunov稳定性原理推导了推力器的开关控制逻辑,能够实现到达目标着陆点的同时进行障碍规避,且该过程不需事先设计参考模型。同时,该控制逻辑具有解析形式,能够实现实时障碍规避。仿真结果表明,该方法能够有效实现规避障碍且满足姿态稳定的要求。Abstract: Aiming at the difficulty in designing the coupled attitude and orbit control lander, the lyapunov-based hazard avoidance control method for landing on small celestial bodies is presented. Firstly, the dynamic model is given, and the is selected based on the current potential of the lander and the threat from the hazards. Then, the on-off logic of the thrusters is derived according to the Lyapunov theory. This guarantees that the lander can arrive at the landing site and avoid the hazards, and this process. Since the control logic is analytical, this control method can meet the real-time requirement of hazard avoidance and is easy to be applied in the engineering. The simulation results show that this method can avoid the hazards effectively and stabilize the attitude.