A brief review of actuation at the micro-scale using electrostatics, electromagnetics and piezoelectric ultrasonics

Abstract

Though miniaturization and mass production via integrated circuit fabrication techniques have transformed our society, the methods have yet to be successfully applied to the generation of motion, and as a consequence the many potential benefits of microrobotics has yet to be realized. The characteristics of electrostatic, electromagnetic and piezoelectric transduction for generating motion at the micro scale is considered, employing scaling laws and a reasoned consideration of the difficulties in motor fabrication and design using each method. The scaling analyses show that electrostatic, electromagnetic and piezoelectric actuators all have comparable force scaling characteristics of F / L 2 ; if one employs permanent magnets, electromagnetic forces do not scale as F / L 4 . Though the torque, (, of piezoelectric ultrasonic motors scale rather poorly with ( / L 4 , they have the clear advantage of possessing torque amplitudes some two orders of magnitude larger than motors employing the other transduction schemes at the micro scale.

Single Source Hybrid Drive for Multi-Functional Ultrasonic Motor

“…The most common piezoelectric motors have single func tion; either linear or rotary [2], If the mobile element produces output along a slider or a linear rail, it is called linear motor and its mobile element is named as slider. Similarly, if stator's vibrations rotate the mobile element around a fixed axis, the motor is rotary type and mobile element is usually named as rotor.…”

“…Therefore, a new type of actuator class with micrometer accuracy and dimensions spanning from couple of hundred micrometers to ten millimeters is essential. As a result of this need, novel actuators based on smart materials have been introduced which are perfect fit for the unpopulated meso-scale range [2]. Amongst these mid range systems with smart materials, piezoelectric motors drew the largest attention because of their high power density, stable efficiency even at smaller scales and high accuracy with very short response time [3][4][5].…”

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

“…Orbital or spherical trajectories are relatively simple to realise. Compared to typical electromagnetic motors, piezoelectric motors provide large force or torque at small size, powerless holding-force, magnetic insensitivity, and are well-suited for miniaturisation [5,6].…”

Analysis of longitudinal and torsional resonance vibrations of a piezoelectrically excited bar by introducing piezoelectric loss coefficients

“…Depending on the operating frequency of the targeted application, assumptions and parameters analyzed in the vibration models differ significantly. For example, studies on low-frequency piezo-bar applications such as unimorph or bimorph cantilever-based micro grippers and tactile feedback devices focus on static deflection of the structure and hysteresis neglecting the effects of resonance (Chang et al, 2010;Liu et al, 2010;Low and Guo, 1995;Park and Kim, 2011;Rakotondrabe et al, 2009). On the contrary, modeling of piezo-bars utilized for high frequency applications such as energy harvesting, vibration damping, and ultrasonic motors primarily consider resonance effects.…”