| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 100 === Passive vibration isolator is due to the simple structure and low cost; therefore, it is still a wide range of applications in the industry, but the drawback of passive isolator workbench is it can’t change system parameters and the bandwidth is fixed. In order to improve the drawback, this study applies tunable air springs to design passive vibration isolation, and add a linear vibration absorber and an autoparametric vibration absorber(AVA) to the system. The Linear vibration absorber and the passive vibration isolation comprise VAI (Vibration absorbing isolator) system, the linear vibration absorber can reduce medium frequency vibration of isolator, and isolator can reduce high frequency vibration of ground; AVA can absorb amplitude of low frequency resonance. In this study, first to model the VAI, then apply numerical software to simulate and verify. Simulation results demonstrate that, air pressure can change the natural frequency of system and linear absorber, and the tunable linear absorber can reduce vibration of isolator effectively; Second, use motion function to do the time-domain analysis of AVA, and use multiple-scale analysis method to analyze the effect of parameters on AVA. Experimental verification, apply laser displacement sensor to measure stiffness of air spring, and use exciter’s sweep mode to excite isolator to measure natural frequency. After repeatedly adjust internal air pressure of air spring, the results show that it can change the natural of isolator, and the performance of reducing vibration is better than industrial product. Finally, verify the performance of VAI and AVA, the results show that VAI can reduce about 40% vibration amplitude in some frequency bandwidth. Because of the assembly of AVA parts, pendulum’s damping coefficient is too large, so the AVA can’t reduce vibration. Using cantilever beam to substitute for pendulum can improve the damping coefficient of AVA .
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