This paper provides a comprehensive review of the literature regarding precision piezoelectric motors over long ranges based on the principle of repeating a series of small periodic step motions, named “frequency leveraged motors” in this paper. A summary of recent research into frequency leveraged motors is presented. Work is classified into three categories by different frequency driving methods, including ultrasonic motors, quasi-static motors (non-resonant motors), and motors combined resonant and quasi-static operations. Pros and cons of each motor type are discussed in term of their principle, structure, and performance. In addition, future perspectives and improvements of the frequency leveraged motor are also provided. It is summarized in such a way can provide a better understanding of the core characteristics of each type of long range piezoelectric motor. Moreover, it also aids in determining successful designs, suitability for applications and further research areas.

A review of long range piezoelectric motors using frequency leveraged method

This paper provides a comprehensive review of the literature regarding actuator systems which are based on the principle that combines the friction and inertia effect, named friction–inertia principle in this paper; such actuators is called friction–inertial actuator (FIA). The contribution of this paper lies in the generalization of various published (including patented) FIAs into a general principle with three specific principles. They are further taken as a framework upon which various published FIAs are classified and compared in terms of their principle, structure, and performance. In addition, this paper shows how this framework would allow for further innovation on FIAs. In the process of this generalization and classification, some confusion presented in the literature is also clarified. This paper also discusses further effort that may be taken to advance the friction–inertia actuation technology.

Piezoelectric friction–inertia actuator—a critical review and future perspective

Local analysis of co-dimension-one and co-dimension-two grazing bifurcations in impact microactuators

A review of recent studies on non-resonant piezoelectric actuators

Piezoelectric inertia motors—also known as stick-slip motors or (smooth) impact drives—use the inertia of a body to drive it in small steps by means of an uninterrupted friction contact. In addition to the typical advantages of piezoelectric motors, they are especially suited for miniaturisation due to their simple structure and inherent fine-positioning capability. Originally developed for positioning in microscopy in the 1980s, they have nowadays also found application in mass-produced consumer goods. Recent research results are likely to enable more applications of piezoelectric inertia motors in the future. This contribution gives a critical overview of their historical development, functional principles, and related terminology. The most relevant aspects regarding their design—i.e., friction contact, solid state actuator, and electrical excitation—are discussed, including aspects of control and simulation. The article closes with an outlook on possible future developments and research perspectives.

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Piezoelectric Inertia Motors—A Critical Review of History, Concepts, Design, Applications, and Perspectives.

A smooth impact rotation motor was fabricated and successfully operated using a torsional piezo actuator. Yoshida et al. reported a linear type smooth impact motor in 1997. This linear motor demonstrated a high output force and a long stroke. A superior feature of the smooth impact drive is a high positioning resolution compared with an impact drive. The positioning resolution of SIDM (smooth impact drive mechanism) is equal to the piezo displacement. The reported positioning resolution of the linear type was 5 nm. Our rotation motor utilized a torsional actuator containing multi-layered piezoelectric material. The torsional actuator was cylindrical in shape with an outer diameter of 15 mm, an inner diameter of 10 mm, and a length of 11 mm. Torsional vibration performance was measured with a laser Doppler vibrometer. The obtained torsional displacement agreed with the calculated values and was sufficient to drive a rotor. The rotor was operated with a saw-shaped input voltage (180 V; 8 kHz). The revolution direction was reversible. The maximum revolution speed was 27 rpm, and the maximum output torque was 56 gfcm. In general, smooth-impact drives do not show high efficiency; however, the level of efficiency of our results (max., 0.045%) could be increased by improving the contact surface material. In addition, we are studying quantitative consideration, for example, about the optimum pre-load or frictional force.

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Y. Okamoto

Papers

A smooth impact rotation motor using a multi-layered torsional piezoelectric actuator