基于正负刚度并联永磁隔振器的隔振性能分析及实验验证

Analysis and experiment of a magnetic levitation vibration isolator with the positive stiffness and the negative one in parallel

针对超精密领域小负载隔振的新需求,基于正负刚度并联原理,采用永磁弹簧和橡胶带相结合的方法,永磁弹簧提供正刚度,橡胶带提供负刚度,提出了一种正负刚度并联永磁隔振器的新构型。为了研究该隔振器的隔振性能,通过实验与理论相结合的方法,建立了橡胶带拉力和刚度的数学模型,验证了橡胶带拉力解析模型的有效性;建立了正负刚度并联永磁隔振器的动力学方程,分析了该隔振器的隔振性能;搭建了永磁弹簧和正负刚度并联永磁隔振器实验台,分别进行隔振性能测试。实验结果表明该隔振器隔振性能的理论计算和实验测试的结果比较吻合,且具有良好的隔振性能;该隔振器最大特点在于其最大承载能力时,刚度最低,固有频率最低,低频隔振性能最好。

In order to develop a new type of vibration isolator for a miniature instrument,a magnetic levitation vibration isolator(MLVI)with a permanent magnetic spring(PMS)in combination with rubber ligaments was proposed,in which,the magnetic spring provides the positive stiffness and the rubber ligament supplies the negative one.For studying the vibration isolation performance of the isolator,an analytical model of the stretched force of the rubber ligament was built and validated by an experiment,which proves that the analytical expression is efficient.Then an analytical expression of the stiffness of the rubber ligament was deduced by the derivative of the stretch force to the vertical deformation of the rubber ligament.As a case study of the isolator,the dynamic characteristic of the isolator was analyzed.A vibration isolator table was constructed to verify the vibration isolation performance of the isolator.The transmissibility curves of isolator were calculated and tested by the instrument.The experimental results show that there is a good agreement between the measured transmissibility and the calculated ones,which proves that the negative stiffness can partially offset the positive one.The main advantages of the isolator is when the load capacity of the isolator achieves the maximum value with the lowest stiffness,the isolator obtains the lowest natural frequency.Compared with the experimental data of the permanent magnet spring and the MLVI,it demonstrates that it is a valid method to explore the new MLVI.