Ultra-sonic distance sensor and monitoring of surface profile utilizing ultra-sonic distance sensor.

摘要

An ultra-sonic distance sensor generates ultra-sonic waves and transmit same toward a target surface, the distance to which is to be measured, through a predetermined path. The sensor is also provided with a reference surface which reflects ultra-sonic waves, which reference surface is disposed within the aforementioned predetermined path of the ultra-sonic waves. A receiver associated with an enabling means receives the ultra-sonic waves reflected by the reference surface or by the target surface, selectively. Arithmetic operations based on the elapsed time between transmission of the ultra-sonic waves and reception of the ultra-sonic waves from the reference surface derive the transmission velocity of the ultra-sonic wave based on the known distance to the reference surface. On the basis of the derived transmission velocity and the elapsed time measured with respect to the ultra-sonic waves reflected by the target surface, the distance to the target surface is derived. The aforementioned ultra-sonic sensor is used to monitor the external shape of an object. In order to monitor the external shape of the object, a system is composed of a plurality of the ultra-sonic sensors. The sensors comprises a primary sensor or sensors directed toward the external surface of the object and an auxiliary sensor or sensors directed to a reference line.