基于反馈线性化和保性能控制的轴向磁轴承单侧线圈故障容错控制

Single coil fault-tolerant control for axial magnetic bearing based on feedback linearization and guaranteed cost control

针对轴向永磁偏置磁轴承一侧线圈无电流时磁轴承承载能力下降且非线性增强的情况,提出一种反馈线性化与保性能控制相结合的组合容错控制策略来提高轴向磁轴承在故障情况下的承载能力并使其能在承重时稳定悬浮转子。首先,建立了故障情况下后轴向磁轴承-转子系统的非线性动力学模型,通过反馈线性化方法使系统大范围线性化。然后,在考虑参数摄动的基础上设计最优保性能控制器使转子稳定悬浮。最后,在轴向一侧线圈无电流的永磁偏置磁悬浮转子上进行了多项实验。实验结果表明,所设计的组合容错控制器实现了承重情况下转子的稳定悬浮,摄动最大的参数变化约35%时位移跳动量峰值为2.6μm,超调量小于3%,调节时间为82ms。结果验证了该方法不仅能实现容错控制,而且具有良好的动静态性能及鲁棒性。

Axial magnetic bearing has a lower load capacity and enhanced nonlinear characteristics when there is no current in one of the coils of magnetic bearing. In order to increase the load capacity and to stabilize the rotor successfully, a combined fault-tolerant control strategy was proposed integrated by feedback linearization and guaranteed cost control. First, an axial nonlinear dynamic model of axial magnetic bearing-rotor system was established, and it is linearized in a wide range by feedback linear- ization method. Then, on the basis of varied parameters, an optimal guaranteed cost controller was designed to control the rotor to be suspended in stability and robustness. Finally, several kinds of ex- periments were performed on the magnetically suspended rotor when there was no current in one of the coils. Obtained results show that the proposed controller can successfully stabilize the rotor when the bearing loads the gravity of rotor. When the parameter is changed by 35%, the peak value of dis- placement is 2.6μm, the overshoot is less than 3%, and regulating time is 82 ms. The results demon- strate the validity of proposed controller and show its excellent fault-tolerant control ability and dy- namic and static characteristics.