Systematic characterization and calibration of a three dimensional ultrasonic positioning system for use in mobile robots

Abstract

This thesis examined the characteristics of the Hexamite Hx11 ultrasonic sensor for the purpose of three dimensional positioning for mobile robots with multi-plane motions. The sensor system was studied and an experiment was conducted to locate a still transponder in the air using three transmitters on the ground. Due to the angular range of the transponder and the transmitters, data were not logged all of the time. An approximate lower z limit boundary surface was calculated, which predicted the behavior of 70% of the tests in the experiment. Sporadic errors were present in some of the data, with no apparent relation to the geometry of the experiment. If the erroneous parts were to be excluded, the accuracy and precision of the data obtained seemed to be quite high. It is concluded that further researches still needed to be done to determine the sources of the sporadic errors that appeared in some the data, and as of date, the Hexamite Hx11 ultrasonic positioning system cannot be reliably used for three dimensional sensing.