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.

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 With Dual Reaction-Mass Type Actuators

1999 ◽  
Author(s):  
Takeshi Mizuno ◽  
Takeshi Negishi
Keyword(s):  
Measurement System ◽  
Mass Measurement ◽  
Piezoelectric Actuators ◽  
Reaction Mass ◽  
Vibration Absorber ◽  
System A ◽  
Experimental Apparatus ◽  
Measurement Object ◽  
The Masses ◽  
Mass Type

Abstract A mass measurement system using two reaction-mass type actuators as a vibration generator and a vibration absorber were studied both theoretically and experimentally. In the system, a measurement object is attached to one reaction mass. The principles and features of the measurement system were described. An experimental apparatus was developed in which bimorph-type piezoelectric actuators were used to drive the masses. The experimental results demonstrated that the developed system could measure mass accurately.

Optimization of a Two Degree of Freedom System Acting as a Dynamic Vibration Absorber

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
M. Febbo ◽  
S. A. Vera
Keyword(s):  
Simulated Annealing Algorithm ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
System A ◽  
Annealing Algorithm ◽  
Minimum Amplitude ◽  
Two Degree Of Freedom ◽  
Heuristic Criterion

This paper deals with the problem of finding the optimal stiffnesses and damping coefficients of a two degree of freedom (2DOF) system acting as a dynamic vibration absorber (DVA) on a beam structure. In this sense, a heuristic criterion for the optimization problem will be developed to contemplate this particular type of DVA. Accordingly, it is planned to minimize the amplitude of vibration in predetermined points of the main structure. Two optimizations will be proposed for two DVAs of 1DOF to compare their performances with the optimized 2DOF system. A simulated annealing algorithm is used to obtain the DVA’s optimal parameters for minimum amplitude in a given point of the beam. The best configuration depends on the location of the absorbers on the beam and, for a fixed location, on the distribution of the stiffness constants.

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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