Linear angle measurement using continuous wave ultrasonic oscillator

Abstract

We investigated the possibility of linear angle measurement of a vessel using a pair of partially submerged ultrasound transducers mounted on its walls. Measurements of the transfer function at different tilts of the vessel showed noticeable changes both in magnitude and phase responses. These changes were found easiest to track from the output frequency of an oscillator formed by using the transducers in a positive feedback loop. The output frequency depended on the tilt parabolically and its relative scatter was found lower compared to that of the angular output of an industrial accelerometer. The achieved output frequency capture rate of 150 measurements per second enabled meaningful tracking of dynamic changes of the test rig tilt in real time.

Comparison of implementations of driving electronics for ultrasonic oscillating sensors

“…These circuits are complemented by a microcontroller which measures the output frequency and communicates it to a PC; and sets the VGA, PS and BPF according to the instructions entered by the user via the PC ( fig.1a). This architecture was successfully applied to the design of the oscillating ultrasonic temperature [4] and tilt [6] sensors.…”

Embedded Supervisory Control and Output Reporting for the Oscillating Ultrasonic Temperature Sensors

“…[4][5][6][7]). Cost requirements force the utilization of mass produced transducers operating in the 20 to 50 kHz frequency range.…”