An Ultra-Low Frequency Two DOFs’ Vibration Isolator Using Positive and Negative Stiffness in Parallel

Min Wang,Xuedong Chen,Xiaoqing Li

doi:10.1155/2016/3728397

Min Wang, Xuedong Chen + Show 1 more

Open Access

https://doi.org/10.1155/2016/3728397

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Abstract

With the improvement of performance in the ultra-precision manufacturing engineering, the requirements for vibration isolation have become increasingly stringent. In order to get wider effective bandwidth and higher performance of vibration isolation in multiple DOFs system, an ultra-low frequency two DOFs’ vibration isolator with positive and negative stiffness in parallel (PNSP) is proposed. The two DOFs’ isolator which combines a positive stiffness (PS) air spring with a negative stiffness (NS) magnetic spring in parallel and combines a PS flat spring with an NS inverted pendulum in parallel is designed to reduce the natural frequency and broaden the effective bandwidth in horizontal and vertical direction. Based on this structure, stiffness models of different components in different directions are established. Compared with a PS isolator, it possesses the characteristic of high-static-low-dynamic stiffness. The simulation curves also provide strong evidence. Last, a real-time active control system and a spectrum testing and analysis system are used for the contrast experiment between the mentioned PNSP structure and PS only. The experimental results demonstrate that the isolator with PNSP can obviously reduce the natural frequency to 1 Hz and simultaneously maintain the stability of the system and consequently verify the validity and superiority of the mentioned structure.

Highlights

With the improvement of performance in the ultra-precision manufacturing and measuring equipment, the requirements for vibration isolation have become increasingly stringent [1,2,3]
A compact structure with positive and negative stiffness in parallel (PNSP) is designed to reduce the natural frequency and broaden the effective bandwidth of vibration isolation system according to the principle of highstatic-low-dynamic stiffness
A real-time active control system and a spectrum testing and analysis system are employed for contrast experiment between the proposed PNSP structure and positive stiffness (PS) structure

Summary

Introduction

With the improvement of performance in the ultra-precision manufacturing and measuring equipment, the requirements for vibration isolation have become increasingly stringent [1,2,3]. Due to these problems, an effective control mechanism or a new structure is required to attenuate the vibration in order to preserve structural integrity of such systems [4]. Feedforward control shows a significant effect by predicting in advance against the vibration of the base platform and direct disturbance of the machine It can effectively improve the performance of vibration isolation system [6, 7]. The realization of ultra-low frequency still depends on the design of passive structure

Methods

Results

Conclusion