Research And Design Of Positive And Negative Stiffness Parallel Low Frequency Vibration Isolation Unit

Vibration phenomenon exists widely in many fields of mechanical manufacturing and application,which often brings adverse effects such as noise,precision reducing,life reducing,etc.Therefore,it is always an important issue that engineers and technicians pay attention to and focus on solving.For precision instruments and equipment represented by Grating Ruling Machine,harm of low-frequency vibration is particularly significant.In order to eliminate the hazards of vibration as much as possible,passive control,active control,semi-active control and hybrid control solutions are formed gradually.Passive vibration isolator has advantages such as simple structure,low cost,easy maintenance and energy-free.It has been widely used in many practical engineering problems which are solved well by passive vibration isolator.However,due to its own characteristics,traditional passive vibration isolation structures are facing challenges in low-frequency and ultra-low-frequency vibration problems,and difficult to play an effective role.Therefore,people often adopt cost-effective and complex method of active control.Based on previous experience and knowledge,this paper designs and optimizes a positive and negative stiffness parallel vibration isolation unit based on magnetic structure.By dynamic analysis and simulation,the vibration isolation system composed of the positive and negative stiffness parallel unit has good vibration isolation effect under condition of low-frequency basic excitation.The main contents of this paper are as follows:(1)Firstly,walking excitation in the working environment of the Grating Ruling Machine is analyzed,and theoretical model of vibration excitation need to isolate is determined;(2)Secondly,theoretical magnetic negative stiffness structure model is established using appropriate mathematical model of permanent magnet,and optimization analysis of the structure's nonlinear stiffness characteristics is carried out.Effects of structure parameters such as the size of permanent magnet on nonlinear stiffness characteristics are obtained.(3)Finally,parameters suitable for the Grating Ruling Machine of the positive and negative stiffness parallel vibration isolation unit are designed according to requirements.Dynamic characteristics of the system are analyzed,and influence of some system parameters on system characteristics is discussed.Vibration isolation performance of the parallel vibration isolation unit under certain conditions is verified by simulation.