| 摘要 |
<p>PURPOSE: To exactly detect the existence of a vehicle when the phenomenon of multiple-time detection is generated by judging the existence of vehicle in the case where the peak voltage value of a reflected wave detected within an arrival time zone after the transmission of ultrasonic waves exceeds the peak voltage value of a stored floor surface reflected wave. CONSTITUTION: The ultrasonic wave from an ultrasonic sensor S is reflected on the surface of floor and detected in the state where no entering object exists within the range of detection. The peak voltage value of the reflected wave detected by this ultrasonic sensor S is previously stored and the peak voltage value of the reflected wave detected in the arrival time zone previously applied as the time for the floor surface reflected wave to be detected is monitored. Then, the detected peak voltage value of reflected wave is compared with the stored peak voltage value and when the detected peak voltage value of reflected wave exceeds the stored peak voltage value, the existence of vehicle is judged. Thus, the presence/absence of vehicle inside the detection range can be detected.</p> |
