Matching Design of Active Magnetic Bearing and Elastic Support Vibration Isolator

2020 ◽  
Author(s):  
Yichen Yao ◽  
Yixin Su ◽  
Tianye Yu ◽  
Gexue Ren ◽  
Suyuan Yu
Keyword(s):  
Frequency Domain ◽  
Vibration Isolation ◽  
Design Method ◽  
Rotating Machinery ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Vibration Isolators ◽  
Active Vibration ◽  
Matching Relation ◽  
Active Vibration Isolation

Abstract In modern industries, high-speed machinery occupies a fundamental place. However, rotating machinery will inevitably produce a variety of structural noise and vibration. Generally, vibration isolation means can be divided into active vibration isolation and passive vibration isolation, among which the most representative are active magnetic bearings (AMBs) and vibration isolators, respectively. The combination of active magnetic bearings and vibration isolators is widely used in rotating machinery because of its excellent effect in vibration and noise reduction. This paper concentrates on the analysis of the vibration transmission mechanism of the active magnetic bearings coupled with the vibration isolators. A 30 kW prototype pump is taken as an example to help describe the research method. The model of the pump is first established. The stationary pump components and the rotor are respectively modeled through the finite element method and converted to substructure modal expression after low-order modal extraction. The bearing force is simplified to spring-dampers with equivalent stiffness and equivalent damping relating to the exciting frequency. The vibration isolators are simplified as three-dimensional spring-dampers. Based on the model, this paper then investigates the matching relation of the AMBs and the vibration isolators and proposes a dynamic vibration isolation design method for the rotor-AMBs-flexible support system. On the basis of the frequency-domain response of the original design, this design method gives the frequency-domain curves of the desired stiffness and damping of the suitable active vibration isolation, which can be used to guide the controller design of the AMBs and isolators selection. According to the design, we have done laboratory experiments on the prototype pump. The results show that the design method based on matching relation has good performance in vibration isolation.

Semi-Active Vibration Isolation Control for Multi-Degree-of-Freedom Structures

2002 ◽  
Author(s):  
Hidekazu Nishimura ◽  
Yasuhiko Okumura ◽  
Seiji Shimodaira
Keyword(s):  
Vibration Isolation ◽  
Linear Time ◽  
Design Method ◽  
Linear Matrix ◽  
Orifice Area ◽  
Convex Interpolation ◽  
Active Vibration ◽  
Active Damper ◽  
Gain Scheduled ◽  
Active Vibration Isolation

In this paper, we propose a design method of a controller for semi-active vibration isolation. We introduce a mechanism of a semi-active damper, which can change the damping in the ratio of the orifice area, in order to obtain the parameter-varying system model. Consideration of the semi-active damper mechanism is appropriate for the design of the gain-scheduled (GS) controller based on linear matrix inequalities (LMIs). The GS controller consists of four-vertex linear time-invaxiant controllers are obtained by the convex interpolation of these controllers. The designed controller switches at zero velocity of the damper and varies according to both the orifice area and the relative velocity of the isolation layer. By carrying out simulations, it is shown that our proposed method is effective for the suppression of seismic response.

Multi-channel Active Vibration Isolation for the Control of Underwater Sound Radiation From A Stiffened Cylindrical Structure: A Numerical Study

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Huang Xiuchang ◽  
Zhang Zhiyi ◽  
Zhang Zhenhua ◽  
Hua Hongxing
Keyword(s):  
Cylindrical Shell ◽  
Vibration Isolation ◽  
Sound Radiation ◽  
Spatial Average ◽  
Far Field ◽  
Underwater Sound ◽  
Cylindrical Structure ◽  
Vibration Isolators ◽  
Active Vibration ◽  
Active Vibration Isolation

Numerical simulation of vibration control of a submerged stiffened cylindrical structure with active vibration isolators is presented. Vibration transmission from vibrating machinery to the cylindrical structure through the active vibration isolators is analyzed by a numerical model synthesized from frequency response functions (FRFs) and impedances. The coupled finite element/boundary element (FE/BE) method is employed to study the vibro-acoustic behavior of the fluid-loaded cylindrical structure. Sound pressure in the far-field is calculated in terms of the pressure and normal acceleration of the outer surface of the cylindrical shell. An adaptive multichannel control based on the filtered-x least mean squares (FxLMS) algorithm is used in the active vibration isolation. Simulation results have demonstrated that suppression of vibration of the four elastic foundations attached to the cylindrical shell will reduce the spatial-average mean-square velocity and the instantaneous radiated power of the cylindrical shell. As a result, suppression of vibration of the foundations leads to attenuation of sound radiation in the far-field induced by the radial displacement dominant mode of the shell. Moreover, vibration suppression is greatly influenced by the strong couplings among control channels. According to these results, it can be concluded that the proposed method is effective in the analysis of underwater sound radiation control of cylindrical structures.

The assessment of active vibration isolation performance of rotating machinery using power flow and vibrational energy: Experimental investigation

2015 ◽  
Vol 230 (2) ◽  
pp. 159-173 ◽  
Author(s):  
Baijie Qiao ◽  
Tong Zhao ◽  
Xuefeng Chen ◽  
Jinxin Liu
Keyword(s):  
Experimental Investigation ◽  
Fundamental Frequency ◽  
Power Flow ◽  
Vibration Isolation ◽  
Vibrational Energy ◽  
Rotating Machinery ◽  
Measurement Methods ◽  
Energy Characteristics ◽  
Active Vibration ◽  
Active Vibration Isolation

The aim of vibration isolation for rotating machinery is to reduce the energy from the vibration source through transfer paths into the receiver structure. However, the direct measurement of energy characteristics that have been thoroughly researched in theory and numerical simulation is always difficult to implement. In this paper, power flow combined with vibrational energy is applied to assess the performance of active vibration isolation of rotating machinery. The indirect measurement methods associated with both power flow and vibrational energy are proposed and a link between them is established. As the first step in experimental investigation, a simple test rig is performed to verify the proposed measurement methods. The power flow into the foundation is calculated by the proposed time averaged, fundamental frequency and second harmonic frequency methods; the vibrational energy of the foundation is estimated by the driving impedance and mobility methods. The second step is to build another experimental rig for imitating the rotating machinery with active vibration isolation. Under multiple excitations, the power flow from the unbalanced rotor excitation through each actuator into the foundation is calculated by the proposed fundamental frequency method; the vibrational energy is calculated by the proposed mobility matrix method. Finally, comparison of assessing the performance of active vibration isolation between using acceleration and force and using the two energy characteristics are carried out.

Active Vibration Isolation Control for a Multi-Degree-of-Freedom Structure With Uncertainties of its Base

1997 ◽  
Author(s):  
Hidekazu Nishimura ◽  
Akihito Kojima
Keyword(s):  
Vibration Isolation ◽  
Design Method ◽  
Relative Displacement ◽  
Degree Of Freedom ◽  
Robust Performance ◽  
Criterion Function ◽  
Active Vibration ◽  
Controlled Structure ◽  
Active Vibration Isolation

Abstract This paper proposes a design method for an active vibration isolation controller for a multi-degree-of-freedom structure with uncertainties of its base. It is demonstrated that a controller which has a desired performance can be designed even if we don’t precisely know the base dynamics by using the criterion function for the purpose of suppression of the interaction between the controlled structure and its base. In order to minimize this interaction we select the acceleration of the lowest mass of the controlled structure and the relative displacement between the lowest mass and its upper mass as the controlled variables. By simulations and experiments it is verified that the designed controller improves both the control performances and the robust performance under the existence of the base dynamics with uncertainties.

The Test Scheme Research on Active Control of Coupled Vibration between the Multiple CNC Milling Machines and the Flexible Foundation

2011 ◽  
Vol 105-107 ◽  
pp. 664-667
Author(s):  
Qian Lin Peng ◽  
Yao Gang Li ◽  
Fu Dong Ma
Keyword(s):  
Vibration Isolation ◽  
Test Scheme ◽  
Test Model ◽  
Cnc Milling ◽  
Vibration Isolators ◽  
Pilot Scheme ◽  
Milling Machines ◽  
Active Vibration ◽  
Flexible Foundation ◽  
Active Vibration Isolation

Analysis of the study based on the Working principle of machine isolators-flexible foundation system which combines with multiple exciters and sensors, an MIMO active vibration isolation test model is constructed. In addition, the choice of system device and the distribution position of the vibration isolators and sensor are revealed and analyzed. Ultimately the Pilot scheme of the MIMO active vibration isolation Pilot scheme is confirmed.

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
Keyword(s):  
Piezoelectric Transducer ◽  
Vibration Isolation ◽  
Vertical Vibration ◽  
Open Loop ◽  
Negative Effects ◽  
Voltage Controller ◽  
Hysteresis Nonlinearity ◽  
Passive Vibration Isolation ◽  
Active Vibration ◽  
Active Vibration Isolation

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.

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