| The research of the vibration isolation and noise reduction occupies a decisive position in vibration isolation theory and practical research. Mechanical vibration caused by motive power machine has always been a hotspot of engineer circles. Along with the increases of vibration isolation requirement and the development of vibration isolation technology, the history of the passive vibration isolation system can be segmented into three phases, monolayer vibration isolation system, bilayer vibration isolation system and raft vibration isolation system.Once the structure of the passive vibration isolation system is determined, so as its transmissibility. It can only attenuate the vibration whose frequency is higher than the natural frequency, so it is not applicable to isolate low frequency vibration. But the active vibration isolation system can effectively inhibit the low frequency vibration by external energy and feedback system. This just makes up the inadequate of the passive vibration isolation technology, thus makes the active vibration isolation technology become the new research hotspot of vibration control area. But the active vibration isolation system has complicated structure and costs too much. Therefore, the research about semi-active vibration isolation system which is made up of active and passive vibration isolation has been extensively studied. In this paper, maglev technology is used in vibration isolation area. Maglev active vibration isolation components and traditional passive ones are integrated together to build up a semi-active vibration isolation system. The maglev active vibration isolator can adjust its rigidity and damping according to different external incentives under the action of control system to inhibit high frequency vibration and low frequency vibration. So the property of semi-active vibration isolation system is better than active and passive vibration isolation system.Begin with the theory of vibration control and vibration isolation, A maglev vibration isolator which is used in the raft vibration isolation system to build up a semi-active maglev vibration isolation system by learning the experience of conventional monolayer vibration isolation system and conventional bilayer vibration isolation system is designed. This system's dynamic equation is established in this paper. The natural frequency values and vibration isolation transmissibility curves are acquired after establishing the maglev raft vibration isolation system model by using MSC. Adams simulation software. The sensors detect the displacement deviation signal of maglev vibration isolator from its equilibrium position under different incentives source. Then, the control system adjusts the stiffness and damping of maglev vibration isolator according to the signal of sensor in order to make this vibration isolation system has better vibration isolation performances in wide frequency. |
