Obstacle detection system built-in test method and apparatus

摘要

An obstacle detection system includes an acoustic piezoelectric transducer capable of radiating and receiving ultrasonic energy. During a BIT transmission period, a controller briefly enables a transmit circuit which provides an AC transmit signal that induces oscillatory motion in a piezoelectric element within the transducer. At the end of BIT transmission period the controller disables the transmit circuit and begins BIT receive period operation. Once the transmit circuit is disabled, the oscillatory motion of the piezoelectric element begins to dampen out causing the transducer to generate and provide a vibration generated signal which is input to a receive circuit which detects the presence of the vibration generated signal and provides received status signal indicative thereof. If the vibration generated signal is not present during this period, a system fault exists and the controller notifies the system user.