| 摘要 |
<p>PURPOSE:To prevent malfunctioning due to deviation between the direction of advancing a vehicle and that of outputting a sensor beam, by comparing with the second reference distance predetermined the distance detected in a specified time after the detection of the first reference distance predetermined is dicriminated. CONSTITUTION:First and second discrimination means derive a discrimination output when an obstacle reaches first and second reference distances l1 and l2 on a sensor beam 2. A passage detecting means sets, for example, eight obstacle detection points lA, lB...lH between reference distances l1 and l2 and derives an output when an obstacle passes by each of the detection points. In response to the output of a second discrimination means, a relative speed between a vehicle 1 and the obstacle is detected when the obstacle reaches the reference distance l2 and a collision forecast signal is issued when the relative speed exceeds a specified value while an output of the passage detection means exists. Therefore, the passage of the obstacle by all of the obstacle detection points lA-lH is detected though opponent vehicles 3 and 4 cross the reference distances l1 and l2 accidentally, a forecast signal output means will derive no output, which eliminates malfunctioning.</p> |
