1999 Fiscal Year Final Research Report Summary
Study on Compact Fine Positioner with Thermal Compensation Capability
| Project/Area Number |
09650285
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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 |
Intelligent mechanics/Mechanical systems
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| Research Institution | Tokai University (1998-1999)
Ibaraki University (1997) |
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Principal Investigator |
YAMAMOTO Yoshio Tokai University, Fac.of Engineering, 工学部, 助教授 (20272114)
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| Co-Investigator(Kenkyū-buntansha) |
EDA Hiroshi Ibaraki University, Fac.of Engineering, 工学部, 教授 (60007995)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Giant Magnetostrictive Material / Positioning Device / Positioner / Actuator / Smart Material / Thermal Expansion / Rare-earth Alloy |
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| Research Abstract |
In view of the application of giant magnetostrictive materials to compact, fine positioner, two kinds of prototypes have been developed through analyses and design modification. Results of this study are summarized below.
1. In-situ preload meassuring: Proper preloading to giant magnetostrictive materials vital for an efficient use of the material. In-situ preload measuring is available by means of strain measurement of the housing of the positioner. This not only provides accurate preloading but also serves sensing capability of the displacement output of the positioner. Based on the displacement signal, the input current to the solenoid coil can be controlled via feedback to adjust the output.
2. Design elaboration for thermal compensation: When the direct current is supplied to the solenoid coil, joule heat emitted by the coil results in outstanding thermal expansion of the giant magnetostrictive material and nearby parts, which significantly degrades the performance of the positioner. In this study, design modification was made such that the thermal expansion is internally offset.
3. Thermal effect instrumentation system: In order to evaluate the thermal expansion of the various parts of the positioner, a measuring system was newly developed. In this system temperature of the positioner is accurately controlled via external heat source and a variety of measurement signals can be gathered simultaneously including displacement output, strain output, and temperatures on more than one spots.
4. Magnetic circuit design via finite element analysis: Giant magnetostrictive material has a very low permeability and a caution needs to be paid so that sufficient magnetic flux passes through the material. Finite element method was used to analyze the magnetic circuit so that about 80% of the generated flux passes through the material.
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