| 摘要 |
PURPOSE:To secure such restoring force as describing a hysteresis loop as well as to make a truck stoppable with promtitude, by superposing voltage or a current proportionate to a vibration speed of the conveying truck on the specified voltage or current, and exciting an electromagnet for stoppage. CONSTITUTION:When a velocity direction of a conveying truck 11 is a sense of right and positive, exciting voltage of an electromagnet 13 is increased and its attraction is also increased, attracting the truck 11 in a negative direction. On the other hand, when velocity is negative, an exciting current of the electromagnet 13 is decreased and its attraction is also decreased, whereby positive directional force strongly acts on the truck 11. That is to say, force in the opposite direction to the traveling direction acts on the truck 11, and vibrations are gradually damped, therefore along with this, the exciting voltage is also gradually decreased. Accordingly, restoring force F is focused to zero while describing a dwindling oval hysteresis curve, and the truck 11 is promptly stopped. And, in this case, energy equivalent to a hysteresis loop area comes to the shape that it is consumed by the electromagnet 13 and a controller 15 or the like. Thus, such restoring force that describes the hysteresis loop is secured and thereby the truck is promptly stopped and fine adjustment for the position can be done.
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