Structure Design And Analysis Of An Active Vibration Isolation System Applied In Precision Instruments

Micro vibration is a key factor that can affect the accuracy and performance ofprecision instruments. With the continuous improvement in the accuracy of precisioninstruments, the demands for the performance of vibration isolation system is alsoincreasing. Based on the relevant research of existing vibration isolation systems, thisthesis deals with designing the structure of an active vibration isolation system, itssupporting configurations, arrangements, selection and design of key components as wellas with the final isolation performance test of the system.The design requirements and scheme of the active vibration isolation system areproposed with referring to the existing isolation systems. Besides, the structure of theactive vibration isolation system, the arrangement of sensors and actuators, and theselection of elastic components and actuator are also analyzed. A linear dynamic model ofthe isolation system is established.The compression spring is designed. With the establishment of the finite elementmodel of the spring, the axial and radial stiffness and the buckling modes of the spring areanalyzed. Finally, the axial stiffness of the spring is tested, and the error between the testresults and the finite element analysis test turns out to be5.1%.The structure of the table is designed in detail. The finite element model of the upperboard is established and its freedom modes are analyzed. The modal test result reveals thefirst-order modal frequency of the board is106.8Hz, and the error between the modal testresults and the finite element analysis results is less than10%.The natural frequencies of the active vibration isolation system are calculated. Thenexcitation experiments are designed to test the natural frequencies and the test results areconsistent with the theoretical model. The transmissibility of the isolation system aretested, which manifest that the bandwidth of the system lies in about1-200Hz. The passiveresonance peak is declined by28dB when feed-forward control is active.