差动式磁悬浮主动隔振系统的控制机理研究

Control mechanism of a differential magnetic suspension active vibration isolation system

在对磁悬浮主动隔振系统的核心部件——差动磁悬浮主动隔振器的电磁力进行实验测量的基础上,利用最小二乘法对实验数据进行拟合,得到主动隔振器的电磁力-电流-气隙之间关系的实际表达式。提出了一种基于力传递率的主动隔振控制机理,给出了价值函数的表达式。考虑主动隔振器的实际能力,对此价值函数进行修正,得到修正的价值函数,推导出最优反馈矩阵。基于此主动控制机理,建立控制模型,在扫频信号激励下,进行仿真分析。仿真结果表明:差动式磁悬浮主动隔振系统具有良好的隔振特性,与传统的被动系统相比,对低频干扰的隔振效果提高(即:力传递率降低)了2dB-3dB,尤其对谐振频率下的干扰,隔振效果提高了8dB-10dB。为了进一步验证方法的可靠性,搭建实验平台,通过实验方法进行验证。实验结果表明:在低频段有较好的隔振效果,尤其在谐振区附近隔振效果更为明显,提高了6dB-8dB,与仿真结果基本吻合。

Here,the electromagnetic force of a differential magnetic suspension active isolator which was the core component of a magnetic suspension active vibration isolation system was measured by means of experiments.Through experimental measurements and fitting a mathematical expression with least square method,the actual relation expression of electromagnetic force-current-gap was obtained.A control mechanism and a value function for active vibration isolation based on force transmissibility were proposed.Considering the practical capacity of the differential magnetic suspension active isolator,the value function was revised.The revised function and the optimal feedback matrix were deduced.A control model based on the control mechanism was established.Output force responses of the active vibration isolation system and a passive one under excitation of swept-frequency signals were simulated.The simulation results indicated that the active system possesses good effect on vibration isolation;comparing with the passive system,the force transmissibility is reduced by 2-3dB within low-frequency range;especially,around the resonance frequency,the force transmissibility is reduced by 8-10dB.In order to check the reliability of the mechanism,experiments were performed.Experiments showed that the force transmissibility is reduced by 6-8dB around the resonance frequency,so the experimental results agree well with the simulated results.