| 摘要 |
PURPOSE:To control an optional number of control positions for an unmanned truck with just a single detector which is provided to the truck, by having different resonance frequencies with each object to be detected and at the same time changing periodically the oscillation frequency by the detector. CONSTITUTION:The objects a1-an to be detected which contain a tank circuit 9 consisting of a coil 7 and a capacitor 8 are set on the floors FL at plural control positions A1-An respectively. At the same time, a high frequency oscillation type detector 10 which detects selectively the positions A1-An via the objects a1-an is provided to a truck 4. These objects a1-an have different resonance frequencies. A sweep generator 14 oscillates frequencies f1-fn. A timing pulse generating circuit 16 produces pulses based on the output of a time base 13 when the frequencies f1-fn corresponding to frequency selection switches S1-Sn are oscillated from the generator 14. Then only the frequencies oscillated via an AND gate 17 are supplied to a detector 12. The detector 10 obtains the detection signal from the detector 12. |
