Static Analysis of Low Frequency Isolation Model Using Pneumatic Cylinder with Auxiliary Chamber

Abstract

In this paper, a novel low frequency isolation model (LFIM) which is built by integrating the wedge-roller-spring and cam-roller-spring mechanism is proposed. Due to the stiffness opposite of two mechanisms, the LFIM can obtain the low dynamic stiffness, meaning that the system can obtain the desirable low resonant frequency. Instead of using mechanical spring, in this study, the pneumatic cylinder with auxiliary chamber is considered as the air spring, thereby, the dynamic stiffness of the proposed system can be easily adjusted as well as controlled to obtain the design equilibrium position and low stiffness at this position as the weight of the isolated load is changed. Furthermore, the proposed model can convert easily the passive model into semi-active one. By analysis solution, the pressure change process in air spring is obtained, a virtual model of the air spring is then built through Amesim software to verify the pressure mode in the air spring. Next, analyzing the effects of the basic working parameters on the dynamic stiffness of LFIM is realized. Based on the analysis solution, the design procedure for LFIM to obtain the high static low dynamic stiffness characteristic is suggested. Finally, the stability of the equilibrium positions is also investigated. This study result provides a useful solution for designing and analyzing dynamic response of LFIM.