| Project/Area Number |
10044113
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
YOSHIDA Kazuya TOHOKU UNIVERSIYU, GRADUATE SCHOOL OF ENGINEERING, ASSOCIATE PROFESSOR, 大学院・工学研究科, 助教授 (00191578)
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| Co-Investigator(Kenkyū-buntansha) |
DUBOWOKY Ste マサチューセッツ工科大学, 機械工学科, 教授
SHILLER Zvi カリフォルニア大学, ロサンゼルス校・機械および航空工学科, 助教授
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1999: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1998: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Lunar and Plenatry Exploration / Locomotion on Uneven Terrain / Rocker-Bogie suspension / Motion Dynamics / Dynamics Simulation / Traction Control / 6-wheel Rover / Rocker-Bogieシステム / Rocher-Bogieシステム / 自然地形モデリング / 走行経路計画 |
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| Research Abstract |
The goal of this research is to investigate the motion dynamics and navigation control methods for planetary exploration rovers that negotiate natural rough terrain covered by sands, gravel and rocks. This research focus the following three points :
(1) Modeling of rover dynamics and tire mechanics that enable us to simulate the rover motion numerically,
(2) Evaluation of the model by comparing the experimental observation and the numerical simulation,
(3) Investigation of the navigation control laws for less slip, more efficient and safe operation.
In the modeling of the rover dynamics, a simulation software toolbox named the SpaceDyn that works with MATLAB has been developed and applied. Mars exploration rovers under the development by NASA have a unique suspension system called Rocker-Bogie, which capability to go over obstacles was proven by Maars PathFinder mission in 1997. The Rocker-Bogie requires a complicated model of the force-torque equilibrium although, the SpaceDyn simulates such complicated motion of obstacle negotiation with relatively easy programming.
In the experiments, key parameters to model the traction mechanics between the tire and soil are estimated. Slip and stack phenomena is observed with excessive loads and actuator torque saturation, when the rover is climbing up a slope for example. This phenomena is clearly simulated by the numerical model developed here with the experimentally identified traction coefficient versus slip.
Based on the above observation and simulation analysis, it is suggested that (a) equal load distribution on all tires, or if the equalizing is difficult, (b) weighted tire torque distribution, shall be effective for the navigation control with higher efficiency and lower probability of slip, stack and tip-over.
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