Inventors:
Aurel V. Stan - Canton OH
Assignee:
The Goodyear Tire & Rubber Company - Akron OH
International Classification:
G01L 300
Abstract:
Use of ultrasonic stimulation together with a pressure sensitive piezoelectric material in a sensor makes it possible to obtain three dimensional pressure measurements on an object in one operation. A piezoelectric material which is manufactured with a conductive surface on both sides, and shear orientation (i. e. piezo voltage produced by pressure on the material is sensitized in a single axis of the shear plane), and generates a proportional voltage when stretched or compressed (and tension and compression is sensed by the generation of opposite polarity voltages), makes it possible to measure normal forces by ultrasonic stimulation, and shear forces by the generation of piezo voltages, using the same sensor. In a preferred embodiment, multiple sensors are disposed in a high density array, and the various axes for the three dimensional measurements are obtained by varying the orientation of each sensor relative to an adjacent sensor. In an alternative embodiment, at least two differently oriented layers of film are included in each sensor.