基于滑模扰动观测器的磁轴承主动振动控制

Vibration suppression of magnetic bearing based on sliding mode disturbance observer

由于磁悬浮控制力矩陀螺转子的不平衡振动会造成控制力矩陀螺系统的同频扰动,影响卫星姿态控制精度与卫星载荷精度,本文提出了基于滑模变结构扰动观测器的磁轴承主动振动控制方法。首先,对不平衡扰动力和力矩作用下的磁轴承-转子系统进行建模;接着,设计了滑模变结构扰动观测器观测不平衡扰动力和力矩;然后,利用跟踪微分器估计位移传感器输出信号的微分获取速度信号,降低观测器的阶数;最后,将滑模扰动观测器的输出引入磁轴承控制器,对观测得到的同频不平衡扰动力和力矩进行补偿。仿真和试验结果均表明,设计的滑模变结构观测器实现了对不平衡扰动的观测,通过控制器有效地实现了对不平衡扰动的补偿,减少了72%的同频振动。

Abstract： As rotor imbalance can lead to the synchronous disturbances of Magnetically Suspended Control Moment Gyroscopes （MSCMG）, and can reduce the attitude control accuracy and the load accuracy of spacecrafts, A general control strategy based on a sliding mode disturbance observer was proposed to minimize the synchronous vibration caused by unbalance on a rotor. First, a dynamics model of the magnetic bearingrotor system was set up and the sliding mode observer used for disturb ance observation was designed. Then, a Tracking Differentiator （TD） was used to estimate the differ ential signals from a displacement sensor to obtain the velocity signals and to reduce orders of the ob server. Finally, according to the synchronous force estimated by the disturbance observer, a control ler was designed to compensate the vibration caused by unbalance of the rotor. Simulation and experi mental results demonstrate the effectiveness of the proposed approach and the vibration has been de creased by 72%.