Actuator microactuator

Microactuators can be implemented in one or more degrees of freedom, leading to another way to classify them as linear (or prismatic), rotary (or revolute), in-plane (1D-3D), and out of plane (1D-6D). A micromotor contains several movable parts, including the microactuator and a transmission system. The transmission system consists of bending (or flexture) joints and links, rigid links, stick-and-slip contact elements, or micromechanical hinges. Like macroscale actuators, microactuators are chosen for different applications based on tradeoffs between ... 

Dubois, P., Rosset, S., Koster, S., Bufom, J.M., Stauffer, J., Mikhailov, S., Dadras, M., Rooij, Nico- F. de., and Shea, H., Microactuators based on ion-implanted dielectric electroactive polymer membranes (EAP), Presented at 13th International Conference on Solid-State Sensors, Actuators and Microsystems, Seoul, Korea, June 5-9, 2005, 2048. 

Numerous examples of developing conducting polymer actuators to operate as artificial muscles have been described in the literature. For example, a steerable cochlear implant with the CRC Cochlear Implant. (Melbourne, Australia), is under development.126 The microactuator will assist surgeons during implantation of the Bionic... 

Hoffmann J, Plotner M, Kuckling D, Fischer W-J (1999) Photopatteming of thermally sensitive hydrogels useful for microactuators. Sens Actuat 77 139-144 Houbenov N, Minko S, Stamm M (2003) Mixed polyelectrolyte brush from oppositely charged polymers for switching of surface charge and composition in aqueous environment. Macromolecules 36 5897-5901... 

Rosset S, NMaus M, Dubois P, Shea HR (2008) Mechanical characterization of a dielectric elastomer microactuator with ion-implanted electrodes. Sens Actuators A 144 185... 

M. Christophersen, B. Shapiro, and E. Smela, Characterization and modeling of PPy bilayer microactuators. Part 1. Curvature, Sens. Actuators, B, B115 (2), 596-609(2006). 

E.W.H. Jager, O. Inganas, and I. Lundstrom, Perpendicular actuation with individually controlled polymer microactuators, Adv. Mater., 13 (1), 76-79 (2001). 

ElectrocapUlary phenomenon refers to the modification of the interfacial tension by the presence of electrical charges. The first comprehensive investigations on electrocapillary phenomena were performed by Lippman, way back in 1875 [1]. In Lippman s experimental apparatus, the interfacial tension modulation due to electrical effects was observed through a capillary rise phenomenon and hence was later termed as electrocapillarity. A decisive advantage of electrocapillary actuation, in comparison to its thermal counterpart (i.e., the thermocapUlary effect, in which surface tension differentials are created by imposed temperature gradients), is the speed with which electrical potentials can be applied and regulated, with possible characteristic timescales of even less than a few milliseconds. Further, electrocapdlary-based microactuators consume much less power, as compared to the typical thermocapillary microdevices. 

Lee J, Kim C-J (2000) Surface-tension driven microactuation based on continuous electrowetting. J Microelectromech Syst 9 171-180 9. Cho SK, Moon H, Kim C-J (2003) Creating, transporting, cutting and merging liquid droplets by electrowetting-based actuation for digital microfluidic circuits. J Microelectromech Syst 12 70-80... 

Microactuators operate by converting one form of energy (e.g., electrical, thermal, electromagnetic) into kinetic energy of movable components. They are sometimes referred to as microelectromechanical systems (MEMS) actuators, but the later term is more... 

Microactuators, Fig. 1 Diagrams of (a) in-plane electrostatic comb-drive actuator and actuation force and (b) out-ofplane parallel plate electrostatic actuator... 

Microactuators, Fig. 2 Pictures and diagrams of (a) in-plane, surface micromachined electrothermal bimorph MEMS actuator and microactuator bank and (b) in-plane... 

Electrothermal or Thermal Actuation Motion is generated by differential thermal expansion in materials such as sDicon or metals, while heat is typically injected into the actuator by means of Joule heat dissipation. Some actuator components expand more than others due to different cross-sections and therefore electrical resistance. Typical microactuator configurations include in-plane bimorph elements (Fig. 2a), out-of-plane bimorph plates, in-plane Chevron, or bent-beam elements (Fig. 2b) [3]. These types of actuators exhibit larger force capabiUties (in mN range), can achieve displacements of 100 pm or less but generally consume a lot of power (hundreds of mW), and have low bandwidth (Hz to KHz). Common methods of fabrication for electrothermal microactuators include surface micromachining... 

Microactuators are also used in microfluidics for many applications including lab-on-a-chip and implantable drug dehvery systems. Such fluidic actuators can be categorized as follows ... 

Wagner B et al (1992) Microactuators with moving magnets for linear, torsional ot multiaxial motion. Sens Actuators A 32 598-603... 

Sherman F et al (1999) Flow control by using high-aspect-ratio, in-plane microactuators. Sens Actuators 73 169-175... 

The main focus of research on temperature-sensitive hydrogels as microactuators in microfluidic devices has been on microvalves. Hydrogel actuators have a distinct advantage for microvalve applications since they are very soft and encapsulate dust particles encountered in microfluidic flows. Normally, these particles... 

Thin Aims and rolled sheets are the most widely used format in microvalve fabrication. Usually an SMA microvalve consists of an upper and a lower housing integrated with a valve seat and fluidic connections, a membrane, a spacer, and an SMA microactuator. The deformation actuated by the SMA thin film pushes or pulls the spacer to seal or open the valve seat, thus to close or allow the liquid to flow through the valve seat. 

Jeong OC, Yang SS (2000) Fabrication of a thermopneumatic microactuator with a corrugated p -I- silicon diaphragm. Sens Actuat A 80(l) 62-67... 

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