柔性卫星大角度机动的自适应模糊变结构控制

针对柔性卫星大角度机动过程中多种模态的强耦合非线性动力学控制问题,提出了一种自适应模糊变结构姿态控制方法.首先利用拉格朗日方程建立了带柔性附件卫星的动力学模型,然后设计变结构控制器使得系统状态能在有限时间内到达滑模面,并采用自适应模糊系统逼近系统所存在的耦合非线性项.为了削弱变结构控制项所带来的抖动,避免激发柔性附件的高频模态,采用边界层方法来代替开关项,并通过模糊规则表的方法确定边界层的厚度.仿真结果表明,所提出的控制方法既实现了柔性卫星高精度姿态控制,也保证了卫星大角度机动过程中柔性附件弹性模态的有效抑制,系统对各种干扰具有一定的鲁棒性.

Adaptive fuzzy sliding mode attitude control for large angle slew maneuvering of flexible satellite

An adaptive fuzzy sliding mode control was proposed for the attitude stabilization of flexible satellite during large angle slew maneuvering.The dynamic model of the satellite with flexible appendages was derived by Lagrange equation.The sliding mode control was designed to make the state of system reach sliding mode surface in finite time.The adaptive fuzzy system was used to approximate the strong couple nonlinear function between rigid central body and flexible appendage dynamics during large angle slew maneuvering.The sign function was replaced by the saturation function so as to attenuate the chattering phenomena and avoid exciting higher frequency elastic mode.The fuzzy rules were employed to gain the size of boundary layer.Simulation results show that not only attitude stabilization of satellite with high precision is achieved,but also the elastic vibration of flexible appendage is suppressed effectively,and the system is robustness against system uncertainties and environmental disturbances.