Borrowing the Bat's Ear for Automation - Ultrasonic Measurements in an Industrial Environment

This work focuses on measurement principles based on ultrasound for applications in industrial automation. The measurements made are of geometric nature. The methods used are when possible based on experience and/or inspiration from the study of bats. A platform for ultrasonic measurements, that allows a VME-based host computer to transmit and receive signals, with a considerable flexibility has been built. Sensor units utilizing both piezoelectric and electrostatic transducers are used. The dimensions of the units are about 10x10x7 centimeters. Frequencies in the range 40-200 kHz are used. The presented measurements include distance, flat surface spatial angle, object localization, object orientation, and object recognition. To make the methods robust matched filters are used in several of the measurements. Frequency sweeps are used to make the ultrasonic measurements more robust to various environmental parameters. Methods that utilize the new information provided by the frequency sweeps are also suggested.