This paper experimentally and computationally examines the modal sensors integrated
with a recently developed rotary ultrasonic motor (USM) driven by continuous wedge waves of the
fundamental modes with the integer circumferential modal number. The traveling wave is formed
from constructive interference of two equal-intensity standing waves induced by two comb
transducers using dual sinusoidal excitations in 90 degree phase difference. The transducers and
modal sensors are segmented in strips around the circumference of piezoelectric tube in the circular
wedge-like motor stator. The latter are used to monitor the dynamic response of the stator during
operation. The response of USM acquired by the proposed modal sensors has distinct vital
characteristics in different frequency bands. The high-pass signals are used not only to note the
variation in phase difference between excitations but to detect the resonant frequency, which is
altered by payload, wear situation, etc. The low-pass signal reveals the revolution speed and dynamic
reaction of the motor stator exerted by frictions and contact forces because of the rotor. The
time-frequency response of stator is further characterized during the period in which the revolving
direction of rotor is switched over.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.