Review of Electrothermal Actuators and Applications

Abstract

This paper presents a review of electrothermal micro-actuators and applications. Electrothermal micro-actuators have been a significant research interest over the last two decades, and many different designs and applications have been investigated. The electrothermal actuation method offers several advantages when compared with the other types of actuation approaches based on electrostatic and piezoelectric principles. The electrothermal method offers flexibility in the choice of materials, low-cost fabrication, and large displacement capabilities. The three main configurations of electrothermal actuators are discussed: hot-and-cold-arm, chevron, and bimorph types as well as a few other unconventional actuation approaches. Within each type, trends are outlined from the basic concept and design modifications to applications which have been investigated in order to enhance the performance or to overcome the limitations of the previous designs. It provides a grasp of the actuation methodology, design, and fabrication, and the related performance and applications in cell manipulation, micro assembly, and mechanical testing of nanomaterials, Radio Frequency (RF) switches, and optical Micro-Electro-Mechanical Systems (MEMS).

Design and performance evaluation of thin-film actuators based on flexible Ni-Co substrates

“…The resistance of the Pt heater changed with temperature; this property is common to almost all conductors. Therefore, the electric power corresponding to voltages of 1-14 V ranged from 0.0015-0.2422 W. The temperature distribution of the actuator was calculated from the heat generated due to Joule heating and the heat loss through convection (1) Fig. 5 Release process of the thin-film actuator and conduction to the atmosphere and the base plate, respectively.…”

“…Microactuators are generally categorized into five types [1,2]: electrostatic, piezoelectric, electromagnetic, shapememory alloy (SMA), and electrothermal. Electrostatic actuators can generate mechanical motion by changing the stationary electric field in materials [3].…”

Endoscopic Optical Imaging Technologies and Devices for Medical Purposes: State of the Art

“…The electrothermal actuators can be classified into three categories: hot-and-cold arm, Chevron, and bimorph actuators. Such actuators are schematized in Figure 15 [100].…”

“…The electrothermal actuators can be classified into three categories: hot-and-cold arm, Chevron, and bimorph actuators. Such actuators are schematized in Figure 15 [100]. Bimorph electrothermal actuators are frequently used in optical devices, especially to guide the optical mirror by connecting it to the tip of more than one bimorph actuator [101][102][103].…”

Elastically and Plastically Foldable Electrothermal Micro‐Origami for Controllable and Rapid Shape Morphing

“…Piezoelectric-material-based actuators, electrothermal actuators, and electrostatic actuators are capable of achieving out-of-plane motions, [29][30][31][32][33][34] and the electrothermal actuators show potential for generating relatively large folding angles. [35] However, most of these currently available electrothermal actuator designs are not capable of folding beyond 90° from the initial flat state, which limits their usage for application in micro-origami systems where complex shapes with large folding are desired. Moreover, it is not yet clear how to integrate these actuators…”