| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
In order to enable us to monitor or to assure whether a pipe has a safe interior condition, we have designed a self-adjusting vehicle composed basically of a pair of wheel set and a crawler. The vehicle is driven by a directdrive motor so the steering specification is satisfied. The interfaces between the vehicle and its central control processor are also designed and fabricated. At the central control, the collected image is processed.
In fact, the hybrid mechanism composed of wheels, and a crawler is adopted for getting a big force of traction. Since the interior of the pipe is limited in space, the direct drive motor is embedded inside the crawler unit, and both ends of the driving shaft has a worm gear for force of traction's magnification. Also, the screws are placed in opposite directions so that the sprockets for supporting the crawler belt decreases in number. Affects of such variables like a standing angle, twisting angle, angular shift of the center, and angular shift from the
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gravitational direction of the vehicle are considered. Four-times resolution rotary encoders are utilized to collect the variables, and the encoders contribute for controling the vehicle autonomously .
Two units of the crawlers are pressed against the wall of the pipe always in opposite direction from the center of the vehicle. One of the two is controlled as a master and the other one as a slave. Ther fore, the vehicle can move along pipes having various kinds of shape, size, and orientation. Moreover, the vehicle throws a laser beamin its front to extract a three dimensional profile of the pipe interior, and the brighy spot on the pipe is superimposed in the screen and monitored by a CCD camera mounted almost on the center line of the vehicle. The spot position is discriminated from the image data and is determined in 3-D space since the beam is thrown by an on-off control program and the beam angle is given by sensing mirror angles. Image data is transferred to the image processor repetitively while the vehicle moves. The image processor provides a profile of the pipe internal by applying a pattern matching method to the collected data. Less
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