| 摘要 |
PURPOSE:To make the switch to speed feedback control at a correct location, by providing a section to be detected which is detected by a sensor on a car, when the car reaches a switching point to the speed feedback control. CONSTITUTION:When a travelling dolly 1 is in retraction state, a sensor 21 detects a projection 23 and the output is turned on. That is, the state of retraction of the dolly 1 is detected by the sensor 21 and the projection 23. Further, when the dolly 1 starts moving toward a disc 3, the start of movement is detected and when it closes to a switching point to the feedback control, the output of the sensor 21 is turned on and when it reaches the switching point, it is turned off. When the output of the sensor 21 is turned off, a switch 13 is closed and the control is switched to the speed feedback control. Thus, the speed feedback control can be made at a correct position surely without being effected by variance of the moving speed of the car. |
