In this article, a novel fractional-order nonsingular terminal sliding mode (FONTSM) control scheme is developed, which guarantees the desired deployment performance of space tethered satellite (STS) system. The presented control scheme is to stabilize the underactuated deployment mission with only tension regulation. Based on the underactuated model, a practicable integer-order nonsingular terminal sliding mode (IONTSM) controller is designed to realize the deployment of the STS system, with the finite-time stability. Then, to improve the deployment performance, the fractional-order calculus is introduced to raise the FONTSM controller, whose Mittag-Leffler-based uniform ultimate boundedness is proved to ensure the finite-time convergence and steady-state performance. In the FONTSM controller, a fractional-order disturbance observer and a fractional-order adaptive compensation law are proposed, to eliminate the adverse impacts of external disturbances and input saturation, respectively. Moreover, compared to the reported fractional-order sliding mode control strategy of the STS system, a better deployment performance can be obtained by the IONTSM and FONTSM controllers in this work. Finally, the effectiveness of the proposed controllers is verified by groups of deployment simulations of the STS system.

中文翻译：

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空间系留卫星部署的分数阶非奇异终端滑模张力控制


本文开发了一种新颖的分数阶非奇异终端滑模（FONTSM）控制方案，保证了空间系留卫星（STS）系统所需的部署性能。所提出的控制方案是仅通过张力调节来稳定欠驱动部署任务。基于欠驱动模型，设计了一种实用的整数阶非奇异终端滑模（IONTSM）控制器，实现了STS系统的部署，具有有限时间稳定性。然后，为了提高部署性能，引入分数阶微积分来提出FONTSM控制器，并证明了其基于Mittag-Leffler的一致极限有界性，保证了有限时间收敛和稳态性能。在FONTSM控制器中，提出了分数阶扰动观测器和分数阶自适应补偿律，分别消除外部扰动和输入饱和的不利影响。此外，与报道的STS系统分数阶滑模控制策略相比，本工作中的IONTSM和FONTSM控制器可以获得更好的部署性能。最后，通过STS系统的多组部署仿真验证了所提出控制器的有效性。