基于终端滑模的航天器自适应预设性能姿态跟踪控制

针对航天器姿态跟踪控制的快速性需求，提出一类自适应终端滑模有限时间控制方法，通过引入饱和函数解决了终端滑模控制器的奇异问题，并结合实际有限时间稳定概念显式地给出了系统状态收敛时间和收敛范围之间的对应关系；为在提高系统鲁棒性的同时避免控制器抖振，设计了一种新型自适应律估计并补偿未知环境干扰。进一步地，针对如遥感卫星对地扫描成像等姿态跟踪任务中存在的状态约束问题，通过在控制器中引入具有对数形式的预设性能项，使系统滑模面响应具有期望的动态过程，约束了航天器姿态跟踪误差及其一阶导数的变化范围。仿真结果表明，设计的控制器具有较高的控制精度和响应速度，满足实际任务对状态约束的需求，且其控制输出不存在奇异和抖振，具备良好的工程应用价值。

Adaptive prescribed performance attitude tracking control for spacecraft via terminal sliding-mode technique

An adaptive terminal sliding mode based control law is proposed for spacecraft attitude tracking. A saturated function is introduced to avoid sigularity of the traditional terminal sliding mode, and the correspondence between the convergence time and domain of system states is explicitly given based on the concept of practical finite-time stability. To improve the system robusteness and simultaneously elimimate the chattering, a novel adaptive law is developed to estimate and compensate unknown disturbance. Considering the contraints in the process of attitude tracking, a logarithmic-form prescribed-performance term is introduced to ensure a desired transient response of the sliding mode surface and constrain the variation range of the tracking error as well as its first-order derivative. Numerical examples are presented to demonstrate that the control laws developed not only have a high control accuracy and response speed, but also avoid sigularity and chaterring, and thus have great significance in application.