Ultrasonic Motors Using Longitudinal and Bending Multimode Vibrators with Mode Coupling by Externally Additional Asymmetry or Internal Nonlinearity

Abstract

The present paper deals with some ultrasonic motors using longitudinal and bending multimode vibrators with their mode couplings caused by externally additional asymmetry or internal nonlinearity. A rectangular plate vibrator with two corners on one diagonal line cut to make its resonance modes couple with each other was used, along with a rectangular plate vibrator under the condition that two resonance frequencies are obtained, for example, as f L/f B=2.0, because internal nonlinear coupling of parametric vibration between two resonance modes is generated under this condition. Using these vibrators with mode couplings, it was found that some ultrasonic motors of simple form can be constructed. The ultrasonic motor using the phenomenon of mode-coupling vibrations dealt with here is not completely new, and a few trial constructions have already been reported [Jpn. J. Appl. Phys. 24 (1985) Suppl. 24-2, p. 739]. However, their motions were not reversible in ordinary driving with an electrical signal of a constant frequency. In contrast, the motors that the authors proposed in this paper can be expected to have a reversible motion.

Ultraminiature Piezomechanisms

“…The motor steps recorded experimentally are shown in Figure 7.2-7.9. As seen from these graphs, the motor exhibits the typical stair case step of inchworm motor at low frequencies (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) Hz). However, at frequencies above 45 Hz, slippage becomes apparent in the motor step profile.…”

“…Control schemes have been devised to improve the response, speed and precision of these motors. Hatsuzawa et al (1986) and Aoyagi et al, (1992) have subjected the motor response with different input parameters such as frequency, voltage and phase [21,22]. Their studies have shown that for ultrasonic motor, speed is most sensitive to the operating frequency.…”

“…This motor achieved a speed of 120 mm/s with resolution of 0.01 urn. Aoyagi (1992) built a multi-mode motor with the two vibration modes coupled together [22]. By coupling the two modes, a single actuator can be used for excitation.…”

An ultrasonic motor for cryogenic temperature using bolt-clamped Langevin-type transducer

“…The motor's main feature was that it could rotate at higher speeds -4 -than motors previously developed under these conditions. Ultrasonic motors can generally be easily downsized due to their driving principles [9]- [13]. Some of these have been used in several specific environments [14]- [16].…”

A new standing-wave-type linear ultrasonic motor based on in-plane modes

“…These two designs are characterized mainly by their compactness. Since the 1980's, researchers in Japan carried out further research work on compact linear ultrasonic motors [5][6][7][8][9][10][11]. In literatures [8][9][10][11], many kinds of ultrasonic oscillators with multilayer piezoelectric actuators, which could lower the operating voltage and improve the lifetime of an ultrasonic linear motor, were reported.…”