著者

水野 毅 荒木 獻次

出版者

The Society of Instrument and Control Engineers

雑誌

計測自動制御学会論文集 (ISSN:04534654)

巻号頁・発行日

vol.32, no.8, pp.1145-1151, 1996-08-31 (Released:2009-03-27)

参考文献数

10

被引用文献数

9 10

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A new type of mass-measurement system under weightless conditions is proposed which uses a dynamic vibration absorber as a measuring device. 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 whose amplitude is proportional to the mass is generated during rotation. It works as a harmonic excitation and forces a structure supporting the table to vibrate. However, a dynamic vibration absorber attached to the structure is tuned or controlled to reduce the vibration to zero. When the structure does not move at all, the absorber mass vibrates in such a way that the product of the mass and the displacement amplitude is equal to the amount of unbalance, that is, the product of the mass to be measured and its distance from the rotational axis. Therefore, the mass of the object is determined by measuring the displacement amplitude of the absorber mass. In this study, the principles and features of the proposed mass-measurement system are investigated. Experiments are carried out with a developed apparatus having an active dynamic vibration absorber. This apparatus can perform measurement at various rotational speeds because the absorber's natural frequency can be easily tuned by a feedback parameter. Experimental results demonstrate the feasibility of the proposed mass-measurement system.

著者

水野 毅 井村 順一

出版者

公益社団法人 計測自動制御学会

雑誌

計測と制御 (ISSN:04534662)

巻号頁・発行日

vol.57, no.2, pp.114-118, 2018-02-10 (Released:2018-02-20)

参考文献数

8

著者

成澤 慶宜 水野 毅 高崎 正也 石野 裕二 原 正之 山口 大介

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.861, pp.17-00523-17-00523, 2018 (Released:2018-05-25)

参考文献数

17

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A basic single-degree-of-freedom magnetic suspension system consists of one floator, one electromagnet and one amplifier. For multi-degrees-of-freedom control, multiple electromagnets and multiple amplifiers are necessary, which increases the cost of total system. As a means of overcoming this problem, parallel magnetic suspension has been proposed which controls multiple floators or multi-degree-of-freedom motions with a single power amplifier. In this system, all of the suspended points move simultaneously even when a disturbance acts on one of the suspended points solely because all electromagnet's coils are connected. This paper studies the moving direction of each suspended point with respect to a step disturbance in double parallel magnetic suspension system. The analytical study shows that the response direction is determined by the system parameter that relates the response speed of each subsystem. In the slower subsystem, the suspended point moves in the same direction as the applied force while in the faster subsystem, the suspended point moves in the opposite direction. In other words, the slower subsystem has positive stiffness while the faster system has negative stiffness. To confirm this prediction, step responses are measured in the experimental apparatus.

著者

水野 毅 Asief JAVED 石野 裕二 髙﨑 正也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.854, pp.17-00217-17-00217, 2017 (Released:2017-10-25)

参考文献数

19

被引用文献数

2

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A switching stiffness control and a modified variable stiffness control were applied to reduce vibration in the lateral directions in active magnetic suspension system with electromagnets operated in the differential mode. The magnetic suspension system using the attractive force between magnetized bodies is inherently unstable in the normal direction so that feedback control is necessary to achieve stable suspension. In contrast, it is usually stable in the lateral directions because of the edge effects in the magnetic circuits. However, damping in the lateral directions is poor so that vibration is easily induced. In this work, a switching stiffness control was applied to attenuate such vibration. The effectiveness of the switching stiffness control was confirmed experimentally. In addition, a modified control method that varies stiffness continuously was proposed to overcome problems occurring in switching. The efficacy of the modified control method was also confirmed experimentally.

著者

水野 毅 石野 裕二 髙﨑 正也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00558-16-00558, 2017 (Released:2017-05-25)

参考文献数

6

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A new over-flow prevention valve with a trigger mechanism is designed, fabricated and studied experimentally to evaluate its performances. Loading arms are used to transfer combustible fluid such as oil between tankers and tanks. A loading arm is equipped with an over-flow prevention valve for safety. This valve stops the fluid flow when the fluid exceeds a threshold level in a tank. It must be composed of mechanical elements solely because electric components may induce combustion. Therefore, it uses a pneumatic circuit to detect the fluid level and close the valve. The fabricated valve utilizes positive pressure caused by the height difference of fluid level between the tank and the sensor probe instead of negative pressure that was used in a conventional valve. However, the positive pressure is insufficient to close the valve directly. Therefore, a trigger mechanism is introduced between a piston pushed by the positive pressure and a locking mechanism keeping the valve open. This mechanism generates sufficient force to release the lock and close the main valve from the force pushing the piston. The concept, operation principles and the pneumatic circuit design are presented. Experiments simulating actual operation are carried out with the fabricated valve. The sensor probe is inserted into the water with a constant speed by a single-axis robot instead of flowing oil into the tank. The relation between the velocity and the depth when the valve closes are studied experimentally.

著者

水野 毅 酒井 康博 髙﨑 正也 石野 裕二

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00482-16-00482, 2017 (Released:2017-05-25)

参考文献数

23

被引用文献数

2

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A wind-tunnel system for spinning body has been proposed to measure hydrodynamic forces acting on the body. In the proposed system, the body is suspended and rotated by electromagnets. The forces are measured from the control signal for suspension. In the previously fabricated apparatus, eight electromagnets were placed around a wind-tunnel. An optical displacement sensor was used to detect the three-dimensional positions of the body. Stable suspension and three-dimensional positioning of the body were achieved. However, it had several problems; the test section area was rather small and vibration was induced by flowing wind to the floator. To solve such problems, a new wind-tunnel using magnetic suspension is developed. It has two and a quarter times test section area. The position sensor is improved to operate in a differential mode in all the directions. Stable suspension and rotation of the floator are achieved. The floator is kept stably without vibration even in the face of wind. The hydrodynamic forces acting on the spinning floator are measured.

著者

石橋 尚宜 水野 毅 石野 裕二 髙﨑 正也 山口 大介 原 正之 渡邊 怜

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00404-16-00404, 2017 (Released:2017-05-25)

参考文献数

11

被引用文献数

2

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This paper treats a relay-feedback mass measurement system that uses a relay with hysteresis and feeds back the velocity of the object. The measurement system has an on-off relay with hysteresis and switches force acting on the object in relation to its velocity. Such nonlinear control induces a limit cycle. The mass of the object is determined from the period of this cycle. In previous study, the actual trajectory of the limit cycle was different in shape from the theoretical one so that the prerequisites of the estimation formula were not satisfied. The delay of the velocity sensor is a main factor of such degradation. In this paper, the effect of the delay on mass estimation is investigated experimentally and analytically. In addition, an estimating equation including this effect is derived. Experimental result supports the validity of the derived estimating equation.

著者

石野 裕二 水野 毅

出版者

自動制御連合講演会

雑誌

自動制御連合講演会講演論文集 第54回自動制御連合講演会

巻号頁・発行日

pp.323, 2011 (Released:2012-03-09)

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磁気浮上制御系の一つに,ゼロパワー磁気浮上系がある.一方,最近では太陽光発電は安価で数十~百数十Wh/m2と効率がよいものが市販され,さらに小型で大容量のコンデンサが容易に手に入るようになった.これらの技術とゼロパワー磁気浮上系を用いると,一般商用電源からの電力供給なしに,重力環境下でも十分磁気浮上が可能である.そこで太陽電池を電源としたゼロパワー磁気浮上装置の開発を行う.

著者

水野 毅 高崎 正也 村山 誠

出版者

埼玉大学

雑誌

基盤研究(B)

巻号頁・発行日

2004

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本課題では,負の剛性を持つ支持機構を利用したアクティブ除振装置の実用化を目指した研究を実施した.(1)負の剛性を持つ支持機構としてゼロパワー磁気浮上機構を利用した装置では,負の剛性の大きさが除振テーブル上の搭載物の重量によって変化するため,直動外乱に対する剛性が低下してしまうという問題がある.この問題の解決方法として非線形補償法を提案し,浮上対象物の1自由度を制御する磁気浮上基礎実験装置において,提案する非線形補償によって負の剛性の大きさが一定に保たれることを実証した.(2)負の剛性を持つ支持機構をリニアアクチュエータを利用して実現することを提案し,そのための制御方法を明らかにした.さらに,空気圧アクチュエータを利用して除振テーブルの垂直方向の3自由度の運動をアクティブに制御する除振装置を試作し,性能の評価を行った.(3)ゼロパワー磁気浮上機構を利用した除振装置のもう一つの問題は,従来の構造では永久磁石の吸引力によって除振テーブルの全重量を支えなければないので,実用的には除振テーブルの大面積化が難しいことである.この問題を解決する方法として,荷重支持機構を導入することを提案した.支持機構によって,除振テーブルに作用する重力より大きな上向きの力を発生するようにすれば,ベース一正のばね-中間台-ハイブリッド磁石-除振テーブルと単純に下から積み上げていく構成が可能となることを示した.(4)荷重支持機構を備えた6自由度アクティブ除振装置の試作を行なった.垂直方向の3自由度の運動に対して,4つのハイブリッド磁石によるモード制御を適用することによって,直動外乱に対する高剛性を実現できることを実験的に確認した.さらに,非線形補償を導入することによって,除振テーブルに大きな直動外乱が作用しても,高い剛性が維持されることを実証した.

著者

水野 毅 神谷 哲朗

出版者

一般社団法人日本機械学会

雑誌

年次大会講演論文集 : JSME annual meeting

巻号頁・発行日

vol.2005, no.5, pp.481-482, 2005-09-18

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The amplitude of negative stiffness of zero-power magnetic suspension depends on the gap between the electromagnet and the suspended object. It is a problem when such suspension is used in an active vibration isolation system because its stiffness against direct disturbance becomes lower when load is applied to the isolation table. This paper presents a nonlinear feedback control scheme for keeping the amplitude of negative stiffness constant. The efficacy of the derived control scheme is demonstrated experimentally.