Application of Dynamic Vibration Absorbers to Mass Measurement

1997 ◽  
Author(s):  
Takeshi Mizuno
Keyword(s):  
Measurement System ◽  
Mass Measurement ◽  
Vibration Absorber ◽  
Rotational Axis ◽  
Automatic Frequency ◽  
Dynamic Vibration Absorber ◽  
Measuring Device ◽  
Supporting Structure ◽  
Dynamic Vibration ◽  
Auxiliary Mass

Abstract A mass measurement system which uses a dynamic vibration absorber as measuring device is developed. It can measure mass even under weightless conditions like in space stations. In this system, an object to be measured is fixed to a rotating table (rotor) at a distance from the rotational axis. Since it makes the rotor unbalanced, a centrifugal force causes the supporting structure to vibrate during rotation. A dynamic vibration absorber attached to the structure is tuned or controlled to cancel the excitation force. When the structure does not vibrate, the amplitude of motion of the auxiliary mass equals the ratio of the amount of unbalance to the auxiliary mass. Therefore, the mass of the object is determined from the motion of the auxiliary mass. According to the measurement principles, the vibration of the supporting structure must be eliminated. A servocompensator with the performance of automatic frequency tracking is applied to reduce the vibration. Experimental results demonstrate that mass can be measured accurately with the developed measurement system.

Mass Measurement System Using an Undamped Dynamic Vibration Absorber for Weightless Conditions

2003 ◽  
Author(s):  
Takeshi Mizuno ◽  
Shinsuke Sato
Keyword(s):  
Measurement System ◽  
Measurement Accuracy ◽  
Mass Measurement ◽  
Inertial Mass ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
System A ◽  
Measurement Object ◽  
Type Mass

A new vibration-type mass measurement system with an undamped dynamic vibration absorber was developed. In the developed system, a measurement object is attached to the inertial mass of the vibration generator instead of the absorber mass. It has an advantage that the tuning condition of the absorber is not influenced by the mass of measurement objects. The measurement accuracy of the developed system was estimated experimentally when it was fixed on a massive base and on a flexible structure. The results demonstrated that measurement accuracy was almost same in both the cases. It was also shown that the vibration of the table in transient states was reduced by increasing the excitation signal gradually from zero to an amplitude for measurement.

scholarly journals Optimization and analysis of a grounded type dynamic vibration absorber with lever component

2020 ◽  
Vol 103 (4) ◽  
pp. 003685042095988
Author(s):  
Yongjun Shen ◽  
Zikang Xing ◽  
Shaopu Yang ◽  
Xianghong Li
Keyword(s):  
Effective Mass ◽  
Vibration Absorber ◽  
Engineering Practice ◽  
Control Performance ◽  
Mass Ratio ◽  
Dynamic Vibration Absorber ◽  
Amplification Ratio ◽  
Dynamic Vibration ◽  
Optimum Parameters ◽  
Auxiliary Mass

Dynamic vibration absorber (DVA) with large auxiliary mass has better control performance, but it is also more bulky. Therefore, the mass ratio (the ratio of auxiliary mass of DVA to mass of controlled object) is usually limited to make the DVA easy to install and suitable for engineering practice. In this paper a grounded type DVA with lever component is proposed, which aims to increase the effective mass and reduce unnecessary mass to improve control performance of the DVA. Firstly, the motion differential equations of the DVA are established and solved. Secondly, the optimum parameters are obtained based on H∞ and H2 optimization criterion. Then, the performances of the grounded type DVA equipped with and without the lever are investigated. Finally, the control performance of the DVA is compared with other three typical DVAs under H∞ and H2 criterion. In this type DVA there are no global optimum parameters, and larger frequency ratio will get better control performance. If the amplification ratio (the ratio of lever power arm to lever resistance arm) is greater than 1, the introduced lever will contribute to control performance of the DVA. Its control performance is better than those of other three typical DVAs. The use of the lever can increase the effective mass of the DVA, thereby improving the control performance of the DVA. The DVA can achieve good performance at small mass ratio by adjusting amplification ratio, which may provide theoretical basis for the design of new kinds of DVAs.

Development of Mass Measurement Devices for Zero-Gravity Experiments

2010 ◽  
Vol 36 ◽  
pp. 21-30 ◽  
Author(s):  
Takeshi Mizuno
Keyword(s):  
Vibration Control ◽  
Mass Measurement ◽  
Vibration Absorber ◽  
Zero Gravity ◽  
Relay Feedback ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Measurement Devices

A review of mass measurement devices developed by the author is presented. According to the measurement principles, the treated devices are classified into two types. The first type uses a dynamic vibration absorber as a device for both mass measurement and vibration control. The main advantage is no vibration transmitted into the surrounding structures during measurement. The second type uses relay feedback. The advantages are simpler mechanism and robustness against disturbances. In this article, the principles of measurement of each type are presented.

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