scholarly journals Tilt Active Vibration Isolation Using Vertical Pendulum and Piezoelectric Transducer with Parallel Controller

2021 ◽  
Vol 11 (10) ◽  
pp. 4526
Author(s):  
Lihua Wu ◽  
Yu Huang ◽  
Dequan Li

Tilt vibrations inevitably have negative effects on some precise engineering even after applying horizontal and vertical vibration isolations. It is difficult to adopt a traditional passive vibration isolation (PVI) scheme to realize tilt vibration isolation. In this paper, we present and develop a tilt active vibration isolation (AVI) device using a vertical pendulum (VP) tiltmeter and a piezoelectric transducer (PZT). The potential resolution of the VP is dependent on the mechanical thermal noise in the frequency bandwidth of about 0.0265 nrad, which need not be considered because it is far below the ground tilt of the laboratory. The tilt sensitivity of the device in an open-loop mode, investigated experimentally using a voltage controller, is found to be (1.63±0.11)×105 V/rad. To compensate for the hysteresis nonlinearity of the PZT, we experimentally established the multi-loop mathematical model of hysteresis, and designed a parallel controller consisting of both a hysteresis inverse model predictor and a digital proportional–integral–differential (PID) adjuster. Finally, the response of the device working in close-loop mode to the tilt vibration was tested experimentally, and the tilt AVI device showed a good vibration isolation performance, which can remarkably reduce the tilt vibration, for example, from 6.0131 μrad to below 0.0103 μrad.

2012 ◽  
Vol 226-228 ◽  
pp. 328-334
Author(s):  
Chun Sheng Song ◽  
Ye Fa Hu

Active vibration isolation technology can overcome the defects of passive vibration isolation technology that the poor vibration isolation performance in low and resonant frequencies. Compared with other active vibration isolation technologies, magnetic suspension isolation technology has shown useful characteristics, such as wide response frequency range, fast response, high reliability and long-life. However, the control of MSVI is still one of the areas that require further investigation. This paper presents a Fuzzy Neural Networks(FNN) control algorithm for a magnetic suspension isolation vibration system, which is optimized by improved Genetic Algorithm(GA). The output force responses of the FNN and passive vibration isolation system under same excitation are simulated. The simulation results show that the fuzzy control system has much better performance in vibration isolation.


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