Control of a unique active vibration isolator with a phase compensation technique and automatic on/off switching

2010 ◽  
Vol 329 (25) ◽  
pp. 5233-5248 ◽  
Author(s):  
Gianmarc Coppola ◽  
Kefu Liu
Keyword(s):  
Vibration Isolator ◽  
Phase Compensation ◽  
Active Vibration ◽  
Compensation Technique

A Phase Compensation Technique of Sampling Moiré Method for Accurate Single-Shot Phase Analysis

2011 ◽  
Vol 70 ◽  
pp. 243-248
Author(s):  
Shien Ri ◽  
Takashi Muramatsu ◽  
Masumi Saka
Keyword(s):  
Computer Simulation ◽  
Phase Analysis ◽  
Phase Error ◽  
Linear Interpolation ◽  
Small Displacement ◽  
Single Shot ◽  
Phase Compensation ◽  
Compensation Technique ◽  
Moire Method ◽  
Effective Phase

Recently, a technique for fast and accurate phase analysis called sampling moiré method has been developed for measurement of small-displacement distribution. In this study, a distribution of phase error caused by linear interpolation in case with mismatch between the sampling pitch and the grating pitch is theoretically analyzed. Moreover, a technique for effective phase compensation is proposed to reduce the periodic phase error. The performance of our compensation method is validated by a computer simulation. Phase analysis can be performed more accurately even in the case that the sampling pitch does not match to the grating pitch strictly.

A novel active vibration isolator applied for micro-gyro by array of deposited electrodes

2009 ◽  
Vol 15 (7) ◽  
pp. 1017-1026
Author(s):  
Nan-Chyuan Tsai ◽  
Chung-Yang Sue ◽  
Bing-Hong Liou
Keyword(s):  
Vibration Isolator ◽  
Active Vibration

scholarly journals Phase Compensation Technique for Effective Heat Focusing in Microwave Hyperthermia Systems

2021 ◽  
Vol 11 (13) ◽  
pp. 5972
Author(s):  
Seonho Lim ◽  
Young Joong Yoon
Keyword(s):  
Target Area ◽  
Phase Compensation ◽  
Temperature Changes ◽  
Multiple Tumor ◽  
Beam Focusing ◽  
Cancerous Cell ◽  
Multifocal Breast Cancer ◽  
Compensation Technique ◽  
Circular Antenna Array ◽  
Microwave Hyperthermia

In this paper, effective electromagnetic (EM) focusing achieved with a phase compensation technique for microwave hyperthermia systems is proposed. To treat tumor cells positioned deep inside a human female breast, EM energy must be properly focused on the target area. A circular antenna array for microwave hyperthermia allows EM energy to concentrate on a specific target inside the breast tumor. Depending on the cancerous cell conditions in the breast, the input phases of each antenna are calculated for single and multiple tumor cell locations. In the case of multifocal breast cancer, sub-array beam focusing via the phase compensation technique is presented to enhance the ability of EM energy to concentrate on multiple targets while minimizing damage to normal cells. To demonstrate the thermal treatment effects on single and multiple tumor locations, the accumulation of the specific absorption rate (SAR) parameter and temperature changes were verified using both simulated and experimental results.

A Phase Compensation Technique for B-Mode Echoencephalography

1975 ◽  
pp. 395-404 ◽  
Author(s):  
D. J. Phillips ◽  
S. W. Smith ◽  
O. T. von Ramm ◽  
F. L. Thurstone
Keyword(s):  
Phase Compensation ◽  
Compensation Technique

A MEMS PPA Based Active Vibration Isolator - STUDENT AWARD 3RD PLACE $500

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 000853-000880
Author(s):  
Chong Li ◽  
C. Lavinia Elana ◽  
Robert N. Dean ◽  
George T. Flowers
Keyword(s):  
Resonant Frequency ◽  
Quality Factor ◽  
Proof Mass ◽  
Control Voltage ◽  
Stable Range ◽  
Vibration Isolator ◽  
Operating Range ◽  
Stable Operating ◽  
Mass Damper ◽  
Active Vibration

Several types of micro-devices are adversely affected by high frequency mechanical vibrations present in the operating environment. Examples include MEMS vibratory gyroscopes and resonators, and micro-optics. Various types of MEMS vibration isolators have been developed for use in the packaging of these vibration sensitive devices. Passive isolators consist of a spring-mass-damper MEMS device and usually have a very high mechanical quality factor, which makes them susceptible to ringing at the isolator's resonant frequency. Active isolators have been realized by using state sensing of the proof mass motion and feeding one or more of these states back through an actuator to adjust the frequency response of the isolator. For example, the technique known as skyhook damping uses velocity feedback to adjust, and typically increase, the damping of the isolator. Although these technique are doable, they require state sensing or state estimation, with feedback electronics to drive the actuator. A simpler MEMS active vibration isolator architecture employs only a parallel plate actuator (PPA) with the MEMS spring-mass-damper structure. The PPA driven with a DC voltage, in its stable operating range, displaces the proof mass, which results in a change in the effective system spring constant due to the electrostatic spring softening effect. This results in a change in the resonant frequency and the quality factor of the isolator. However, due to the nonlinearities inherent in this type of device, the stable operating range is reduced as the PPA voltage is increased. Furthermore, even when the isolator is stable in steady-state, a sufficiently large transient response can also drive it into the unstable regime, resulting in the electrodes snapping into contact. In this study, the PPA based active vibrator isolator is developed and its performance is evaluated. The characteristics of the transient instability are investigated and its stable range of operation is specified, for booth external disturbances and rapid application of the control voltage. This MEMS PPA based active vibration isolator can improve performance compared to passive isolators, while being much simpler than state feedback active isolators.

Development of Vibration Isolator With Controllable Stiffness Using Permanent Magnets and Coils

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Kai Meng ◽  
Yi Sun ◽  
Huayan Pu ◽  
Jun Luo ◽  
Shujin Yuan ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Permanent Magnets ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stealth Technology ◽  
Active Vibration ◽  
Magnetic Rings

In this study, a novel vibration isolator is presented. The presented isolator possesses the controllable stiffness and can be employed in vibration isolation at a low-resonance frequency. The controllable stiffness of the isolator is obtained by manipulating the negative stiffness-based current in a system with a positive and a negative stiffness in parallel. By using an electromagnetic device consisting of permanent magnetic rings and coils, the designed isolator shows that the stiffness can be manipulated as needed and the operational stiffness range is large in vibration isolation. We experimentally demonstrate that the modeling of controllable stiffness and the approximation of the negative stiffness expressions are effective for controlling the resonance frequency and the transmissibility of the vibration isolation system, enhancing applications such as warship stealth technology, vehicles suspension system, and active vibration isolator.

Recent Study on the Passive and Active Vibration Isolators

2014 ◽  
Vol 494-495 ◽  
pp. 491-496
Author(s):  
Hua Ping Mei ◽  
Hao Yue Tian ◽  
Shuan Huang
Keyword(s):  
Vibration Isolation ◽  
Control Method ◽  
Low Frequency ◽  
Research Direction ◽  
Magnetic Suspension ◽  
High Frequency Oscillation ◽  
Future Research ◽  
Vibration Isolator ◽  
Vibration Isolators ◽  
Active Vibration

The vibration isolators have witnessed significant developments due to pressing demands for high resolution metrology and manufacturing, optical, physical and chemical experiments. In the view of these requirements, the engineers and physicists have exploited different types of vibration isolators. This paper firstly presents the recent developments on the passive vibration isolators. It finds that the passive vibration isolators can constrain the high frequency oscillation. The active control is the efficient method to cancel the low frequency vibration. Then, the paper is concerned with the recent advances on the active vibration isolator. The appropriate actuator, sensor and advanced control method are the key component of the active vibration isolator to enhance their vibration isolation properties. Finally, the author proposes that the magnetic suspension vibration isolator is a future research direction in the field of the vibration isolation.

Active vibration isolator

1986 ◽  
Vol 80 (4) ◽  
pp. 1280-1280
Author(s):  
George T. Pinson
Keyword(s):  
Vibration Isolator ◽  
Active Vibration

A six-axis single-stage active vibration isolator based on Stewart platform

2007 ◽  
Vol 300 (3-5) ◽  
pp. 644-661 ◽  
Author(s):  
A. Preumont ◽  
M. Horodinca ◽  
I. Romanescu ◽  
B. de Marneffe ◽  
M. Avraam ◽  
...  
Keyword(s):  
Stewart Platform ◽  
Single Stage ◽  
Vibration Isolator ◽  
Active Vibration
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