Shahna Mehdi Heydari, Abedi Mostafa
Department of Electrical Engineering, Shahid Beheshty University, Tehran, Iran.
ISA Trans. 2020 Jun;101:23-41. doi: 10.1016/j.isatra.2020.01.034. Epub 2020 Feb 13.
Design of an adaptive anti-unwinding finite time sliding mode algorithm for attitude control system of a three-axis satellite is approached in this paper. In the designed controller, some parameters updating laws are proposed to simultaneously obtain the accurate values of inertia moments, the upper values of reaction wheels' failures and disturbances. Accordingly, the combined finite time stability of the control system and convergence of the satellite parameters has been demonstrated. Also, a new sliding surface is suggested to avoid the unwinding problem which is common in sliding mode techniques. It is proved by the Lyaponov methodology that the satellite quaternions and angular velocities always approach to the nearest equilibrium point and so it prevents the excessive satellite slews. Furthermore, the proposed algorithm has been modified in such a way that the singularity problem does not occur, especially when the system states reach around the equilibrium point. Therefore, the finite time convergence of system states and parameters estimation errors are guaranteed subjected to disturbances and actuator failures without occurring singularity and unwinding problems. Besides rigorous theoretical proofs by the Lyapunov theory, different simulations are exhibited to demonstrate the merits of the developed control schemes.
本文探讨了一种用于三轴卫星姿态控制系统的自适应抗解缠有限时间滑模算法的设计。在所设计的控制器中，提出了一些参数更新律，以同时获得惯量矩的精确值、反作用轮故障和干扰的上限值。相应地，证明了控制系统的组合有限时间稳定性和卫星参数的收敛性。此外，还提出了一种新的滑模面，以避免滑模技术中常见的解缠问题。通过李雅普诺夫方法证明，卫星四元数和角速度总是趋近于最近的平衡点，从而防止卫星过度旋转。此外，对所提出的算法进行了改进，使其不会出现奇异性问题，特别是当系统状态接近平衡点时。因此，在存在干扰和执行器故障的情况下，保证了系统状态和参数估计误差的有限时间收敛，不会出现奇异性和解缠问题。除了通过李雅普诺夫理论进行严格的理论证明外，还展示了不同的仿真结果，以证明所开发控制方案的优点。
