| Project/Area Number |
08650155
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
機械工作・生産工学
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| Research Institution | Science University of Tokyo |
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Principal Investigator |
MURATA Ryoji Science University of Tokyo, Faculty of Science and Engineeing, Professor, 理工学部, 教授 (70201811)
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| Co-Investigator(Kenkyū-buntansha) |
HENMI Nobuhiko Science University of Tokyo, Faculty of Science and Engineering, Assistant, 理工学部, 助手 (80256669)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | tool wear / in-process sensing / cutting sound / frequency analysis / parabolic microphone / microphone array / 旋削加工 / 工具摩耗 / 音響センサ / 歪率 / 音響センサアレイ / 共振周波数 |
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| Research Abstract |
The study deals with the monitoring system for turning process, and investigates under various cutting conditions. Cutting sound is detected by microphones, and is transformed to frequency spectrum by a FFT analyzer. This pays attention to the changes of peak on frequency spectrum of cutting sound as tool wear increases. Experimental results show that when flank wear increases, the peak value increases and the peak frequency reduces slightly.
The method utilizing cutting sound is very effective to detect tool wear as it is non-contact measurement, but at the same time it has a problem. There are many sound sources in practical environment. Surrounding sound interrupts the monitoring system and makes accuracy of detection of tool wear worse. Therefore, it is necessary and indispensable for a practical monitoring system utilizing cutting sound to have an ability to specify the sound source locations.
The study also makes an attempt to give the acoustic sensor sharp directivity in order to detect the only sound from specified sound source. As the method to make directivity, two methods which use a microphone-array or a parabolic refledctor are adopted. Each method is experimentally investigated whether it can specify location of several sound sources and distinguish from other sound sources. In the experiment with the microphone-array, two cutting processes are examined with two lathes.At that time, sounds generated from the lathes are identified by varying direction of the microphone-array. The experiment shows that the array system can hold down sensitivity for unexpected sound from other source than a pointed sound source by the array, and can distinguish expected sound from several sound sources. Another method by the parabolic reflector is examined as well, and almost the same results are obtained.
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