Dynamic Distance and Tactile Force Measurement Using Ultrasonic PVF<inf>2</inf>Transducers

Abstract

An ultrasonic t ime-of-flight detection scheme was developed for measurement of the amount of compression in a rubber column. The amount of compression was empirically related to local tactile force, thereby p roducing a flexible tactile force sensor. To make this device u seful for distributed force measurement on a prothestic or a robotic hand, a 16-element array of these sensors was constructed and tested. Results show a capability of measuring force for 0.1 to 5 N acting normally to a surface area of a 16 mm2. The ultrasonic measurement using a half cycle of a 2 MHz pulse was repeated at a sampling rate of 1000 Hz allowing in dynamic measurement of the amount of l ocal compression or force with a frequency response of at least 200 Hz.