Special Issue "Advances in Actuators"
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A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Physical Sensors".
Deadline for manuscript submissions: closed (31 December 2009)
Special Issue Editor
Guest Editor
Prof. Dr. Sang-Gook Kim
Massachusetts Institute of Technology, Department of Mechanical Engineering, Room 1-310, 77 Massachusetts Ave., Cambridge, MA 02139, USA
Website: http://mit.edu/micronanosystems/www/
E-Mail: sangkim@mit.edu
Phone: +1 617 452 2472
Fax: +1 617 258 8742
Interests: nanomanufacturing; carbon nanotube growth and assembly; PZT MEMS; energy harvesting; non-lithographic MEMS
Special Issue Information
Dear Colleagues,
Actuator is an essential component of electromechanical systems which converts electrical energy into mechanical work. The growing demand for actuators at multi-scales (macro, meso, micro and nano) and in emerging areas such as biomedical applications and micro-autonomous systems requires more robust, efficient and scalable actuator technologies. This special issue of Sensors entitled, “Advances in Actuators,” aims to report recent emerging actuator technologies in response to these demands such as muscle-inspired actuators, design and manufacturing of thin film piezoelectric and shape memory actuators and electro-active polymer actuators. We invite researchers and scientists to submit their latest results and developments for the following topics, but not limited to:
- Artificial muscle actuators
- In-plane linear micro actuators
- Large strain micro actuators
- Design and fabrication of nano actuators
- Multi-scale assembly of micro/nano/meso actuators
- Piezoelectric actuators
- Conducting polymer and dielectric elastomer actuators
- Shape memory actuators
- Low-power actuators
- Novel control technology for emerging actuators (see keywords below)
Prof. Dr. Sang-Gook Kim
Guest Editor
Submission
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed Open Access monthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs).
Keywords
- artificial muscle actuators
- in-plane linear micro actuators
- large strain micro actuators
- design and fabrication of nano actuators
- multi-scale assembly of micro/nano/meso actuators
- piezoelectric actuators
- conducting polymer and dielectric elastomer actuators
- shape memory actuators
- low-power actuators
- novel control technology for emerging actuators
Published Papers (10 papers)
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Received: 18 November 2009; in revised form: 15 December 2009 / Accepted: 16 December 2009 / Published: 28 December 2009
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Abstract: Shape memory alloys (SMAs) offer a high power-to-weight ratio, large recovery strain, and low driving voltages, and have thus attracted considerable research attention. The difficulty of controlling SMA actuators arises from their highly nonlinear hysteresis and temperature dependence. This paper describes a combination of self-sensing and model-based control, where the model includes both the major and minor hysteresis loops as well as the thermodynamics effects. The self-sensing algorithm uses only the power width modulation (PWM) signal and requires no heavy equipment. The method can achieve high-accuracy servo control and is especially suitable for miniaturized applications.
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Received: 7 December 2009; in revised form: 4 January 2010 / Accepted: 18 January 2010 / Published: 20 January 2010
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Abstract: The coupling effects between the mechanical and electric properties of piezoelectric materials have drawn significant attention for their potential applications as sensors and actuators. In this investigation, two piezoelectric actuators are symmetrically surface bonded on a cross-ply composite laminate. Electric voltages with the same amplitude and opposite sign are applied to the two symmetric piezoelectric actuators, resulting in the bending effect on the laminated plate. The bending moment is derived by using the classical laminate theory and piezoelectricity. The analytical solution of the flexural displacement of the simply supported composite plate subjected to the bending moment is solved by using the plate theory. The analytical solution is compared with the finite element solution to show the validation of present approach. The effects of the size and location of the piezoelectric actuators on the response of the composite laminate are presented through a parametric study. A simple model incorporating the classical laminate theory and plate theory is presented to predict the deformed shape of the simply supported laminate plate.
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Received: 1 December 2009; in revised form: 15 December 2009 / Accepted: 11 January 2010 / Published: 26 January 2010
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Abstract: This paper describes the concept and design of a novel artificial hair receptor for the sensing system of micro intelligent robots such as a cricket-like jumping mini robot. The concept is inspired from the natural hair receptor of animals, also called cilium or filiform hair by different research groups, which is usually used as a vibration receptor or a flow detector by insects, mammals and fishes. The suspended fiber model is firstly built and the influence of scaling down is analyzed theoretically. The design of this artificial hair receptor is based on aligned suspended PVDF (polyvinylidene fluoride) fibers, manufactures with a novel method called thermo-direct drawing technique, and aligned suspended submicron diameter fibers are thus successfully fabricated on a flexible Kapton. In the post process step, some key problems such as separated electrodes deposition along with the fiber drawing direction and poling of micro/nano fibers to impart them with good piezoeffective activity have been presented. The preliminary validation experiments show that the artificial hair receptor has a reliable response with good sensibility to external pressure variation and, medium flow as well as its prospects in the application on sensing system of mini/micro bio-robots.
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Received: 25 December 2009; in revised form: 27 January 2010 / Accepted: 20 February 2010 / Published: 26 February 2010
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Abstract: Recently, cellulose has been re-discovered as a smart material that can be used as sensor and actuator materials, which is termed electro-active paper (EAPap). This paper reports recent advances in paper actuators made with cellulose and hybrid materials such as multi-walled carbon nanotubes, conducting polymers and ionic liquids. Two distinct actuator principles in EAPap actuators are demonstrated: piezoelectric effect and ion migration effect in cellulose. Piezoelectricity of cellulose EAPap is quite comparable with other piezoelectric polymers. But, it is biodegradable, biocompatible, mechanically strong and thermally stable. To enhance ion migration effect in the cellulose, polypyrrole conducting polymer and ionic liquids were nanocoated on the cellulose film. This hybrid cellulose EAPap nanocomposite exhibits durable bending actuation in an ambient humidity and temperature condition. Fabrication, characteristics and performance of the cellulose EAPap and its hybrid EAPap materials are illustrated. Also, its possibility for remotely microwave-driven paper actuator is demonstrated.

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Received: 15 January 2010; in revised form: 10 February 2010 / Accepted: 16 February 2010 / Published: 5 March 2010
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Abstract: As a novel biomimetic polymer, we have developed polymer gels with an autonomous self-oscillating function. This was achieved by utilizing oscillating chemical reactions, called the Belousov-Zhabotinsky (BZ) reaction, which is recognized as a chemical model for understanding several autonomous phenomena in biological systems. Under the coexistence of the reactants, the polymer gel undergoes spontaneous swelling-deswelling changes without any on-off switching by external stimuli. In this review, our recent studies on the self-oscillating polymer gels and application to biomimetic actuators are summarized.
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Received: 6 January 2010; in revised form: 3 February 2010 / Accepted: 12 February 2010 / Published: 10 March 2010
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Abstract: Piezoelectrics have widespread use in today’s sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1-x] O3 (PZT),are comprised of more than 60 weight percent lead (Pb). Dueto its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided.
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Received: 22 January 2010; in revised form: 17 February 2010 / Accepted: 2 March 2010 / Published: 25 March 2010
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Abstract: Films of conducting polymers can be oxidized and reduced in a reversible way. Any intermediate oxidation state determines an electrochemical equilibrium. Chemical or physical variables acting on the film may modify the equilibrium potential, so that the film acts as a sensor of the variable. The working potential of polypyrrole/DBSA (Dodecylbenzenesulfonic acid) films, oxidized or reduced under constant currents, changes as a function of the working conditions: electrolyte concentration, temperature or mechanical stress. During oxidation, the reactive material is a sensor of the ambient, the consumed electrical energy being the sensing magnitude. Devices based on any of the electrochemical properties of conducting polymers must act simultaneously as sensors of the working conditions. Artificial muscles, as electrochemical actuators constituted by reactive materials, respond to the ambient conditions during actuation. In this way, they can be used as actuators, sensing the surrounding conditions during actuation. Actuating and sensing signals are simultaneously included by the same two connecting wires.
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Received: 1 January 2010; in revised form: 23 February 2010 / Accepted: 9 March 2010 / Published: 29 March 2010
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Abstract: We have developed a hydraulic displacement amplification mechanism (HDAM) and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS) membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation.
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Received: 6 January 2010; in revised form: 16 March 2010 / Accepted: 31 March 2010 / Published: 13 April 2010
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Abstract: Elastic waves, especially guided waves, generated by a piezoelectric actuator/sensor network, have shown great potential for on-line health monitoring of advanced aerospace, nuclear, and automotive structures in recent decades. Piezoelectric materials can function as both actuators and sensors in these applications due to wide bandwidth, quick response and low costs. One of the most fundamental issues surrounding the effective use of piezoelectric actuators is the quantitative evaluation of the resulting elastic wave propagation by considering the coupled piezo-elastodynamic behavior between the actuator and the host medium. Accurate characterization of the local interfacial stress distribution between the actuator and the host medium is the key issue for the problem. This paper presents a review of the development of analytical, numerical and hybrid approaches for modeling of the coupled piezo-elastodynamic behavior. The resulting elastic wave propagation for structural health monitoring is also summarized.
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Received: 25 February 2010; in revised form: 19 March 2010 / Accepted: 9 April 2010 / Published: 21 April 2010
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Abstract: This study designs and analyzes an impedance pump utilizing an electromagnetic actuator. The pump is designed to have three major components, namely a lower glass substrate patterned with a copper micro-coil, a microchannel, and an upper glass cover plate attached a magnetic PDMS diaphragm. When a current is passed through the micro-coil, an electromagnetic force is established between the coil and the magnetic diaphragm. The resulting deflection of the PDMS diaphragm creates an acoustic impedance mismatch within the microchannel, which results in a net flow. In performing the analysis, simulated models of the magnetic field, the diaphragm displacement and the flow rate are developed using Ansoft/Maxwell3D, ANSYS FEA and FLUENT 6.3 CFD software, respectively. Overall, the simulated results reveal that a net flow rate of 52.8 μL/min can be obtained using a diaphragm displacement of 31.5 μm induced by a micro-coil input current of 0.5 A. The impedance pump proposed in this study provides a valuable contribution to the ongoing development of Lab-on-Chips (LoCs) systems.

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Last update: 12 January 2011