高阶滑模下的多智能体绳网捕获系统抓捕控制

Capture control of multi-agent tether-net systems based on higher-order sliding mode

摘要:

为应对空间碎片对在轨航天器的威胁,对柔性绳网捕获系统的四角自主机动单元增加了模块化对接系统,使其能够对接成一个组合拖曳航天器,便于后续拖拽离轨任务的实施,提高捕获成功率并有效防止了目标物的逃逸。首先,针对在轨捕获过程中柔性绳网带来的振动问题以及四角自主机动单元协同作动的难点,将高阶滑模算法与一致性编队协同策略结合,设计了一种新型控制方法。其次,对基于质量集中法的绳网捕获系统的动力学模型进行了单自由度仿真分析,比较了不同滑模算法与文中算法控制效果及燃料消耗情况。最后,确立了超螺旋滑模算法与领航—跟随者多智能体一致性方法结合的最优控制组合,并成功应用于全自由度的在轨捕获仿真中。仿真结果表明:二者结合设计的新型控制器能够在50 s内完成对目标物的在轨捕获,具备优异的鲁棒性与有效性；同时,四角的自主机动单元能够在捕获过程中保持姿态角波动不超过3°,充分满足自主机动单元对接系统工作的客观条件,并有效衔接了在轨捕获阶段与离轨拖曳阶段的过渡性研究。

Abstract:

To deal with the threat of space debris to on-orbit spacecraft, modular docking systems are added to the four-corner autonomous maneuvering units of the flexible net capture system. The units can assemble into a combined towing spacecraft, which is convenient for the implementation of subsequent deorbiting tasks, effectively preventing target escape and increasing the capture success rate. Firstly, to address the vibration problem caused by the flexible tether net in the on-orbit capture process and the challenges in coordinated actuation of the four-corner autonomous maneuvering units, a new control method is designed by combining the higher-order sliding mode algorithm with the consensus formation cooperative strategy. Secondly, the single-degree-of-freedom simulation analysis of dynamic model of the tether net capture system based on the mass concentration method is carried out. The control effect and fuel consumption of different sliding mode algorithms and the algorithm in this paper are compared. Finally, the optimal control combination of the super-twisting sliding mode algorithm and the leader-follower multi-agent consensus method is established, and successfully applied to the full-degree-of-freedom on-orbit capture simulation. The simulation results show that the new controller can complete the on-orbit capture of the target within 50 s, which exhibits excellent robustness and effectiveness. At the same time, the four-corner autonomous maneuvering units can keep the attitude angle fluctuation less than 3° during the capture process, which fully meets the objective conditions for docking systems of autonomous maneuvering units. The research effectively connects the transition between the on-orbit capture stage and the deorbit towing stage.