精密加工平台隔振系统多频振动控制

Vibration control of a precision fabrication platform under multiple frequency excitations

近年来,随着精密加工与精密测量等技术的发展,微振动对加工精度和测量灵敏度的影响变得十分突出;传统的被动隔振器由于结构和参数固定,不能满足复杂激励环境下的隔振要求;主动隔振能量消耗大,且高频易失稳;以磁流变弹性体为代表的半主动控制技术不仅具有功耗低、稳定性好等特点,还能根据外界激励变化实时调节参数,成为振动控制领域的研究热点。针对精密加工平台系统中存在的多频振动问题和隔振系统的非线性,提出采用磁流变弹性体隔振器和分频模糊控制相结合的方法;建立了磁流变弹性体隔振系统动力学模型,推导适用于磁流变弹性体隔振系统的半主动控制条件,针对多频振动设计不依赖于系统模型的分频模糊控制器。通过控制试验验证了所设计控制器的有效性;与常规模糊控制器相比,所提方法对多频振动具有更好的抑制。

Recently,with the development of precision machining and precision measurement technology,how to reduce the micro-vibration in precision fabrication platforms has attracted more attention.The existing micro-vibration control methods mainly are the passive and active vibration isolation methods.However,the mentioned two methods have their own limitations.As the structure and parameters are fixed,the traditional passive vibration isolator has a poor adaptability for various kinds of vibrations.The active one with high power consumption is unstable for high frequency vibration isolation.As a typical semi-active control technology,magnetorheological elastomer(MRE)with the advantages of low power consumption and good stability has become a hotspot in vibration control fields,whose parameters such as stiffness and damping in real time can be adjusted according to the external excitation.In the paper,a MRE isolator combined with a fuzzy controller(FC)was used to suppress the vibration of the platform under multi-frequency excitations and to deal with the nonlinearity of the isolation system.The model of MRE isolation was established,and the semi-active control conditions applicable to the MRE vibration isolation system were derived.Considering the high nonlinearity of the MRE isolator and the multiple frequency excitation,a frequency-division FC was designed.The effectiveness of the designed controller was verified by control experiments.The designed controller is independent of the system’s precise model and can maintain the vibration attenuation performance at a satisfactory level.