TEMPERATURE COMPENSATING METHOD FOR ULTRASONIC RANGE FINDER

摘要

PURPOSE:To enable an accurate distance measurement to be performed without delay even when an external temperature suddenly changes by constructing an ultrasonic range finder such that a temperature compensation is conducted by using a temperature change detected by measuring a unit distance by an ultrasonic wave. CONSTITUTION:The space propagation time To of an ultrasonic wave signal for which the signal transmitted from an ultrasonic wave generator 10 is propagated through a unit distance lo and received by an ultrasonic wave receiver 11 is counted by a counter circuit 13 to be fed to an arithmetic circuit 7. When the circuit 7 is given the time To from the circuit 13, the circuit 7 calculates a temperature correcting compensating value alpha and stores it. On the other hand, a time Tx for which an ultrasonic wave signal P fed from an ultrasonic wave generator 2 is reflected from an object 1 to be measured and received by a receiving circuit 5 via an ultrasonic wave receiver 4 is counted by a counter circuit 6. When given the time Tx from the circuit 6, the arithmetic circuit 7 calculates a distance Xo to the object 1 by using a sonic velocity at a reference temperature to and corrects the value of the distance Xo with the correcting value alpha. As a result, the measured value of the distance to the object to be measured can be corrected without delay.