| 摘要 |
PURPOSE: A method for determining the abnormal state of an ultrasonic sensor is provided to determine an abnormal state by using a receiving state and a receiving time of an ultra wave reflected from an object. CONSTITUTION: A control portion(110) outputs a control signal for transmitting an ultrasonic wave. An ultrasonic wave transmission portion(121) of an ultrasonic sensor(120) transmits a predetermined ultrasonic wave according to the control signal of the control portion(110). The transmitted ultrasonic wave is reflected by an object(130). The control portion(110) checks whether an ultrasonic reception portion(122) receives the ultrasonic wave reflected by the object(130) or not. The control portion(110) determines the ultrasonic sensor(120) as an abnormal state if the ultrasonic reception portion(122) does not receive the ultrasonic wave reflected by the object(130). The control portion(110) outputs a control signal for generating an alarm sound and a signal for displaying the abnormal state of the ultrasonic wave sensor(120). A display portion(150) displays the abnormal state of the ultrasonic wave sensor(120). The control portion(110) determines the abnormal state of the ultrasonic sensor(120) by comparing a receiving time with a predetermined receiving time if the ultrasonic reception portion(122) receives the ultrasonic wave reflected by the object(130).
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