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Journal articles on the topic 'Actuation thermale'
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1
Yoon, Kwang Joon, Kyu Young Kim, Nam Seo Goo, Hyun Chul Park, and J. R. Haw. "Actuator Performance Degradation of Piezo-Composite Actuator LIPCA under Cyclic Actuation." Key Engineering Materials 261-263 (April 2004): 1331–36. http://dx.doi.org/10.4028/www.scientific.net/kem.261-263.1331.
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This paper is concerned with the fatigue characteristics of LIPCA (LIghtweight Piezo-Composite Actuator) device system. LIPCA device system is composed of a piezoelectric ceramic layer and fiber reinforced light composite layers, typically a PZT ceramic layer is sandwiched by a top fiber layer with low CTE (coefficient of thermal expansion) and base layers with high CTE. The advantages of the LIPCA design are using the lightweight fiber reinforced plastic layers without compromising the generation of high force and large displacement and to have design flexibility by selecting the fiber direction and the size of prepreg layers. In addition to the lightweight advantage and design flexibility, the proposed device can be manufactured without adhesive layers when we use resin prepreg system. To investigate the degradation of actuation performance of LIPCA due to the repeated fatigue loading, the repeated loading tests up to several million cycle were performed and the actuation displacement for a given excitation voltage was measured during the test. The fatigue characteristics was measured using an actuator test system consisted of an actuator supporting jig, a high voltage actuating power supplier, and a non-contact laser measuring system and evaluated.
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Zhang, Xi, Jinxuan Zhang, Bidita Salahuddin, Shuai Gao, Shazed Aziz, and Zhonghua Zhu. "Reversible Torsional Actuation of Hydrogel Filled Multifilament Fibre Actuator." Actuators 10, no. 9 (September 21, 2021): 244. http://dx.doi.org/10.3390/act10090244.
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Twisted polymer fibre actuators provide high torsional rotation from stimulated volume expansion, induced either by chemical fuelling, thermal stimulation, or electrochemical charging. One key limitation of these actuators is the irreversibility of torsional stroke that limits their feasibility when considering real-life smart applications. Moreover, scaling the torsional stroke of these actuators becomes difficult when these are integrated into practically usable systems such as smart textiles, due to the external and variable opposing torque that is applied by the adjacent non-actuating fibres. Herein, a simple composite type torsional actuator made of hydrogel coated commercial textile cotton multifilament fibre is demonstrated. This novel actuator is of high moisture responsiveness, given that hydrogels are capable of providing huge volume expansion and twisting the overall system can transform the volumetric expansion to fibre untwisting based torsional actuation. Theoretical treatment of torsional actuation is also demonstrated based on the change in torsional stiffness of dry and wet fibres as well as a few externally applied torques. The agreement between experimental measurements and theoretical estimation is found reasonable, and the investigation allows the near-appropriate estimation of torsional stroke before integrating an actuator into a smart system.
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Lloyd, George M., Kwang J. Kim, A. Razani, and Mohsen Shahinpoor. "Investigation of a Solar-Thermal Bio-mimetic Metal Hydride Actuator." Journal of Solar Energy Engineering 125, no. 1 (January 27, 2003): 95–100. http://dx.doi.org/10.1115/1.1531147.
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Metal hydrides have been investigated for use in a number of solar thermal energy applications, such as heat regenerators or hydrogen storage technology, but rarely for thermal actuators. Preliminary experimental results from a prototype solar thermal metal hydride actuator, using copper-encapsulated porous metal hydride compacts of LaNi5, indicate that this thermal-mechanical system can produce high specific forces (over 100 (N/g)), with response times on the order of seconds. These operational characteristics, along with features such as being bio-mimetic, compact, operationally safe, lubricationless, noiseless, soft actuating, and environmentally benign, result in an actuator that is ideal for many industrial, space, defense, and biomedical applications. In this paper, we report recent work directed toward predicting and characterizing the performance bounds of the actuator, specifically concentrating on elements which might comprise an actuator driven by concentrated solar radiation. A complete solution of the 1-D governing heat and mass transfer equations with an ideally selective reactor surface are used to predict bounds on performance in terms of volume flow rates and realistic actuation times. The advantages and disadvantages of the design are discussed from this perspective. The preliminary data show a great potential for these metal hydride actuators to be used for solar thermo-mechanical applications.
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Motzki, Paul. "Efficient SMA Actuation—Design and Control Concepts." Proceedings 64, no. 1 (November 21, 2020): 20. http://dx.doi.org/10.3390/iecat2020-08520.
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The versatility of the form factors of thermal shape memory alloys (SMA) in combination with their unique actuation and sensing abilities allow for the design and construction of innovative multifunctional systems. Despite the considerable number of advantages, such as their exceptional energy density, only a few SMA-based actuator systems are commercially available. One of the main reasons for this is their inefficient thermal activation and the resulting high energy consumption. The efficiency of SMA-based actuator systems can be improved by innovative design and control approaches. In the first part of this paper, the intelligent combination of SMA actuator wires with bi-stable, nonlinear spring elements is described. This combination eliminates the commonly quoted disadvantages of SMAs—slow actuation and energy inefficiency—for a wide range of applications. In particular, two energy-free actuator configurations are realized, which can be applied to any non-proportional actuation tasks. The second approach for the realization of high-speed actuation and energy efficiency is the activation of SMA wires with high voltage pulses, which leads to actuation times in the millisecond range and energy savings of up to 80% in comparison to the suppliers’ recommendations. It is shown that even high AC voltages such as typical mains supplies can be directly used for highly efficient SMA activation.
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Oh, Il Kwon, and Dong Hyun Kim. "Frequency Tuning Characteristics of Multi-Layered Micro-Resonators Using Thermal and Piezoelectric Actuation." Key Engineering Materials 324-325 (November 2006): 647–50. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.647.
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Frequency tuning characteristics of the multi-layered micro-resonators have been extensively investigated by using thermal and piezoelectric actuations. Based on the layerwise displacement theory and geometric nonlinear formulation, the nonlinear deformation and its attendant vibration characteristics of un-symmetrically deposited camped-camped micro-beams under piezoelectric and thermal actuations have been analyzed. The effects of the eccentric piezoelectric actuation and uniform thermal loading on the large deflection and natural modes were discussed with respect to geometric nonlinear responses and initial imperfection. Present results show that both piezoelectric and thermal actuations can effectively tune the resonant frequencies as increasing and decreasing desired values by the alternative selection of the dominance between in-plane deformation and out-of-plane deformation.
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Almadani, Ibrahim Khalil, Ibrahim Sufian Osman, and Nasir Ghazi Hariri. "In-Depth Assessment and Optimized Actuation Method of a Novel Solar-Driven Thermomechanical Actuator via Shape Memory Alloy." Energies 15, no. 10 (May 22, 2022): 3807. http://dx.doi.org/10.3390/en15103807.
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Currently, energy demand is more significant than ever due to population growth and advances in recent technologies. In order to supply more energy while maintaining a healthy environment, renewable energy resources are employed. This paper proposes a novel solar-driven shape memory alloy thermomechanical actuator as an eco-friendly solution for solar thermal applications. The proposed actuator was assessed numerically and experimentally. The numerical tests showed that the designed actuation mechanism’s inner temperature has a minimum variation per day of about 14 °C and a temperature variation of 19 °C for most days of the year, which allows for proper activation and deactivation of the actuator. As for the experimental tests, the presented actuation mechanism achieved a bi-directional force of over 150 N, where the inner temperatures of the actuator were recorded at about 70.5 °C while pushing forces and 28.9 °C while pulling forces. Additionally, a displacement of about 127 mm was achieved as the internal temperature of the actuator reached 70.4 °C. The work presented adds to the body of knowledge of a novel solar-based self-driven actuation mechanism that facilitates various applications for solar thermal systems.
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Pal, Jitendra, Yong Zhu, Jun Wei Lu, and Dzung Viet Dao. "A Novel Bidirectional Z-Shaped Thermally Actuated RF MEMS Switch for Multiple-Beam Antenna Array." Advanced Materials Research 705 (June 2013): 264–69. http://dx.doi.org/10.4028/www.scientific.net/amr.705.264.
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In this paper RF MEMS switchis designed for dielectric-embedded electronically switched multiple-beam (DE-ESMB) antenna array. To achieve small stiffness without buckling, a novel bidirectional Z-shaped thermal actuator is used instead of V-shaped thermal actuator, which can generate large displacement and high contact force at low actuation voltage. With the actuation current from-0.6 A to 0.6 A, the electrothermal actuator can achieve a bidirectional motion in a dynamic range of-10.08 μm to 10.17 μm.RF performances are improved by suspending the structure 25 μm from the substrate using MetalMumps process. An ON state insertion loss of-0.14 dB at 10 GHz and an OFF state isolation of-67 dB at 10 GHz are achieved on low resistivity silicon substrate.
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Cartolano, Mark, Boxi Xia, Aslan Miriyev, and Hod Lipson. "Conductive Fabric Heaters for Heat-Activated Soft Actuators." Actuators 8, no. 1 (January 21, 2019): 9. http://dx.doi.org/10.3390/act8010009.
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We examine electrically conductive fabrics as conductive heaters for heat-activated soft actuators. We have explored various fabric designs optimized for material properties, heat distribution and actuation/de-actuation characteristics of the soft actuators. We implemented this approach in the silicone/ethanol composite actuators, in which ethanol undergoes a thermally-induced phase change, leading to high actuation stress and strain. Various types of conductive fabrics were tested, and we developed a stretchable kirigami-based fabric design. We demonstrate a fabric heater that is capable of cyclic heating of the actuator to the required 80 °C. The fabric with the special kirigami design can withstand temperatures of up to 195 °C, can consume up to 30 W of power, and allows the actuator to reach >30% linear strain. This technology may be used in various systems involving thermally-induced actuation.
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Yun, Sungryul, Seongcheol Mun, Seung Koo Park, Inwook Hwang, and Meejeong Choi. "A Thermo–Mechanically Robust Compliant Electrode Based on Surface Modification of Twisted and Coiled Nylon–6 Fiber for Artificial Muscle with Highly Durable Contractile Stroke." Polymers 14, no. 17 (August 31, 2022): 3601. http://dx.doi.org/10.3390/polym14173601.
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In this paper, we propose a novel and facile methodology to chemically construct a thin and highly compliant metallic electrode onto a twisted and coiled nylon–6 fiber (TCN) with a three–dimensional structure via surface modification of the TCN eliciting gold–sulfur (Au–S) interaction for enabling durable electro–thermally–induced actuation performance of a TCN actuator (TCNA). The surface of the TCN exposed to UV/Ozone plasma was modified to (3–mercaptopropyl)trimethoxysilane (MPTMS) molecules with thiol groups through a hydrolysis–condensation reaction. Thanks to the surface modification inducing strong interaction between gold and sulfur as a formation of covalent bonds, the Au electrode on the MPTMS–TCN exhibited excellent mechanical robustness against adhesion test, simultaneously could allow overall surface of the TCN to be evenly heated without any significant physical damages during repetitive electro–thermal heating tests. Unlike the TCNAs with physically coated metallic electrode, the TCNA with the Au electrode established on the MPTMS–TCN could produce a large and repeatable contractile strain over 12% as lifting a load of 100 g even during 2000 cyclic actuations. Demonstration of the durable electrode for the TCNA can lead to technical advances in artificial muscles for human–assistive devices as well as soft robots those requires long–term stability in operation.
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Lee, Taik Min, Young Ho Seo, Kyung Hyun Whang, and Doo Sun Choi. "Study on the Lateral Piezoelectric Actuator with Actuation Range Amplifying Structure." Key Engineering Materials 326-328 (December 2006): 289–92. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.289.
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A novel piezoelectric micro-actuator with actuating range amplification structure has been proposed. This actuator is unique in that the leverage type amplification structure enables large actuating movement with low voltage. In case of general piezoelectric thin film actuator, applied voltage is low and almost zero power is consumed. Its switching time is very fast in comparison with electrostatic actuators and thermal actuators. However, the most drawback of piezoelectric actuator is short actuating range. A 100μm length PZT actuator can only make movement of 100. In this research, we suggest an actuator which can provide geometric amplification of the PZT strain displacement in lateral direction. The lateral piezoelectric MEMS actuator was fabricated and its actuating range was measured. The actuator shows maximum lateral displacement of 1.1μm, and break-down-voltage of the thin film PZT actuator is above 16V.
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Li, Hua, Yannan Wu, Haochen Ye, and Yan Xu. "Thermal Actuation Analysis of Twisted and Coiled Polymer Actuators." International Journal of Applied Mechanics 12, no. 08 (September 2020): 2050092. http://dx.doi.org/10.1142/s1758825120500921.
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Twisted and coiled polymer actuators (TCPAs), an emerging class of artificial muscles, exhibit the advantages of large stroke, low hysteresis, low cost, etc. The effect of design parameters on thermal actuation is important for the effective design of TCPAs. In this study, a new model has been developed to describe the effect of geometrical parameters on thermal actuation based on Castigliano’s second theorem. In this model, an equivalent modulus based on its radial bias angle has been introduced from the twisted polymer actuator (TPA)’s equivalent model. The proposed model provides a simple and accurate expression to describe the TCPA’s thermal actuation by using its fundamental characteristic. The proposed model was validated with respect to the experimental data from the literature and subsequently used in the parametric analysis of TCPA. The numerical results show that the amplitude of actuation increases linearly with pitch angle and nonlinearly with spring index.
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Muralidharan, M., S. Jayachandran, M. Yogeshwaran, A. S. Shivaani, and I. A. Palani. "Thermo mechanical and Control Behaviour of Copper based Shape Memory Alloy Bimorph Actuator towards the Development of Micro Positioning System." Defence Science Journal 70, no. 6 (October 12, 2020): 664–71. http://dx.doi.org/10.14429/dsj.70.15516.
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A shape memory alloy (SMA) bimorph actuator is a composite structure composed of flexible polyimide substrate and SMA thin film deposited using thermal evaporation technique. In this work, the substrate thickness in the range of 25 - 75 mm was selected for the development of CuAlNiMn SMA bimorph actuator. An investigation on the control behavior of copper based SMA bimorph towards the development of micro positioning system has been performed. The actuation behavior of the SMA bimorph was studied using electrical actuation. Subsequently, a proportional integral derivative (PID) controller was designed to control the bimorph actuator with proper tuning of gain parameters. The displacement of the bimorph actuator was controlled through dedicated experimental setup consisted of laser displacement sensor, data acquisition system and LabVIEW software. The CuAlNiMn SMA bimorph actuator resulted in a satisfying control performance which can be extended to MEMS applications. A preliminary prototype of the SMA bimorph actuator based micro positioning system has been developed.
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Hui, Weiwei, Hexiang Zhang, Jianlei Wang, Xuanshi Meng, and Huaxing Li. "Heat transfer characteristics of plasma actuation in different boundary-layer flows." Physics of Fluids 34, no. 3 (March 2022): 034110. http://dx.doi.org/10.1063/5.0084420.
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The coupling characteristics of the aerodynamic and thermal effects of a surface dielectric barrier discharge plasma actuator and its transfer characteristics in different boundary-layer flows are studied experimentally. The actuator is attached to the surface of a flat-plate airfoil and driving by an alternative-current signal. Different boundary-layer flows are achieved in the wind tunnel by adjusting the airfoil's angle of attack with a Reynolds number of 2.02 × 105. The spatial temperature-rise distributions and velocity fields induced by plasma actuation in quiescent air show that the influence range of temperature is consistent with that of the induced velocity field. The aerodynamic and thermal effects induced by plasma actuation have strong coupling characteristics. The heat around the actuator is limited within the boundary-layer flows with a 15 m/s incoming flow. The temperature rise outside the boundary layer is close to zero. In the turbulent boundary-layer flow, the temperature is lower than that in the laminar boundary-layer flow as a whole. The maximum temperature-rise difference exceeds 10 °C. In the leading-edge separation-bubble flow, most heat generated by the plasma actuation is restricted inside the separation bubble. The results provide references for the mechanism detection of related plasma icing-control and flow-control research.
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Inoue, Shozo, K. Morino, Keisuke Yoshiki, and Takahiro Namazu. "Effect of Substrate Temperature on the Shape Memory Behavior of Ti-Ni-Cu Ternary Alloy Sputtered Films." Materials Science Forum 706-709 (January 2012): 1903–8. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.1903.
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The purpose of this work is to establish a deposition process of Ti-Ni-Cu films showing shape memory effect in the as-deposited state. 5-µm-thick Ti50Ni35Cu15 films have been deposited onto thermally oxidized (001) Si wafer by triple-source dc magnetron sputtering at various substrate temperatures. Their shape memory behavior were characterized by XRD, DSC measurements and thermal cycling tests under various constant tensile stresses. We have confirmed that crystalline films can be grown directly when the substrate temperature exceeds 400°C. The films deposited at higher than 450°C showed thermoelastic martensitic transformation and their Ms temperature slightly increased with increasing substrate temperature. Since their Ms temperature were found to be higher than 30°C, they can be used as an actuator at RT. These films were also found to have higher critical stress against plastic deformation than the post-deposition crystallized films. We have also tried to fabricate a prototype of micro-actuator and to characterize their actuation behavior and have confirmed that TiNiCu/SiO2 double layered diaphragm showed an actuation response to a pulsed current of more than 100Hz.
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Zhao, Yusen, Chiao-Yueh Lo, Lecheng Ruan, Chen-Huan Pi, Cheolgyu Kim, Yousif Alsaid, Imri Frenkel, Rossana Rico, Tsu-Chin Tsao, and Ximin He. "Somatosensory actuator based on stretchable conductive photothermally responsive hydrogel." Science Robotics 6, no. 53 (April 7, 2021): eabd5483. http://dx.doi.org/10.1126/scirobotics.abd5483.
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Mimicking biological neuromuscular systems’ sensory motion requires the unification of sensing and actuation in a singular artificial muscle material, which must not only actuate but also sense their own motions. These functionalities would be of great value for soft robotics that seek to achieve multifunctionality and local sensing capabilities approaching natural organisms. Here, we report a soft somatosensitive actuating material using an electrically conductive and photothermally responsive hydrogel, which combines the functions of piezoresistive strain/pressure sensing and photo/thermal actuation into a single material. Synthesized through an unconventional ice-templated ultraviolet–cryo-polymerization technique, the homogenous tough conductive hydrogel exhibited a densified conducting network and highly porous microstructure, achieving a unique combination of ultrahigh conductivity (36.8 milisiemens per centimeter, 103-fold enhancement) and mechanical robustness, featuring high stretchability (170%), large volume shrinkage (49%), and 30-fold faster response than conventional hydrogels. With the unique compositional homogeneity of the monolithic material, our hydrogels overcame a limitation of conventional physically integrated sensory actuator systems with interface constraints and predefined functions. The two-in-one functional hydrogel demonstrated both exteroception to perceive the environment and proprioception to kinesthetically sense its deformations in real time, while actuating with near-infinite degrees of freedom. We have demonstrated a variety of light-driven locomotion including contraction, bending, shape recognition, object grasping, and transporting with simultaneous self-monitoring. When connected to a control circuit, the muscle-like material achieved closed-loop feedback controlled, reversible step motion. This material design can also be applied to liquid crystal elastomers.
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Xia, Boxi, Aslan Miriyev, Cesar Trujillo, Neil Chen, Mark Cartolano, Shivaniprashant Vartak, and Hod Lipson. "Improving the Actuation Speed and Multi-Cyclic Actuation Characteristics of Silicone/Ethanol Soft Actuators." Actuators 9, no. 3 (July 28, 2020): 62. http://dx.doi.org/10.3390/act9030062.
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The actuation of silicone/ethanol soft composite material-actuators is based on the phase change of ethanol upon heating, followed by the expansion of the whole composite, exhibiting high actuation stress and strain. However, the low thermal conductivity of silicone rubber hinders uniform heating throughout the material, creating overheated damaged areas in the silicone matrix and accelerating ethanol evaporation. This limits the actuation speed and the total number of operation cycles of these thermally-driven soft actuators. In this paper, we showed that adding 8 wt.% of diamond nanoparticle-based thermally conductive filler increases the thermal conductivity (from 0.190 W/mK to 0.212 W/mK), actuation speed and amount of operation cycles of silicone/ethanol actuators, while not affecting the mechanical properties. We performed multi-cyclic actuation tests and showed that the faster and longer operation of 8 wt.% filler material-actuators allows collecting enough reliable data for computational methods to model further actuation behavior. We successfully implemented a long short-term memory (LSTM) neural network model to predict the actuation force exerted in a uniform multi-cyclic actuation experiment. This work paves the way for a broader implementation of soft thermally-driven actuators in various robotic applications.
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Liu, Zirui, Bo Sun, Jianjun Hu, Yunpeng Zhang, Zhaohua Lin, and Yunhong Liang. "Ethanol Phase Change Actuator Based on Thermally Conductive Material for Fast Cycle Actuation." Polymers 13, no. 23 (November 24, 2021): 4095. http://dx.doi.org/10.3390/polym13234095.
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Artificial muscle actuator has been devoted to replicate the function of biological muscles, playing an important part of an emerging field at inter-section of bionic, mechanical, and material disciplines. Most of these artificial muscles possess their own unique functionality and irreplaceability, but also have some disadvantages and shortcomings. Among those, phase change type artificial muscles gain particular attentions, owing to the merits of easy processing, convenient controlling, non-toxic and fast-response. Herein, we prepared a silicon/ethanol/(graphene oxide/gold nanoparticles) composite elastic actuator for soft actuation. The functional properties are discussed in terms of microstructure, mechanical properties, thermal imaging and mechanical actuation characteristics, respectively. The added graphene oxide and Au nanoparticles can effectively accelerate the heating rate of material and improve its mechanical properties, thus increasing the vaporization rate of ethanol, which helps to accelerate the deformation rate and enhance the actuation capability. As part of the study, we also tested the performance of composite elastomers containing different concentrations of graphene oxide to identify GO-15 (15 mg of graphene oxide per 7.2 mL of material) flexible actuators as the best composition with a driving force up to 1.68 N.
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Orłowska, Karolina, Wojciech Majstrzyk, Andrzej Sierakowski, Tomasz Piasecki, and Teodor Gotszalk. "Mechanical Impedance Analysis of a Novel MEMS Photon Force Sensor." Proceedings 2, no. 13 (November 29, 2018): 921. http://dx.doi.org/10.3390/proceedings2130921.
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In this work we present how to describe mechanical impedance of a photon force (PF) MEMS sensor dedicated to structures’ optomechanical studies. An actuating force (photon force) is caused by the reflection and absorption of the electromagnetic radiation beam due to the radiation pressure effect. Specially designed very soft (low k-constant, ca 10–150 mN/m) cantilevers are presented. The structures integrate a Lorentz loop, which enables electromagnetic actuation. The construction with two mirrors is proposed so that parasitic thermal actuation can be neglected. The MEMS displacement is measured with the use of a laser vibrometer. The mechanical impedance model is presented using which the stiffness is calculated. As validation measurements: thermal noise and known mass adding methods are used.
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Leopold, S., T. Geiling, C. Fliegner, D. Pätz, S. Sinzinger, J. Müller, and M. Hoffmann. "Multifunctional LTCC Substrates for Thermal Actuation of Tunable Micro-Lenses Made of Aluminum Nitride Membranes." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, CICMT (September 1, 2013): 000124–30. http://dx.doi.org/10.4071/cicmt-2013-wp14.
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Thin membranes are widely used for tunable micro-lenses, where the membrane, usually made from polymers, defines the surface of a subjacent liquid. If the liquid is pressurized, the membrane deflects and forms a lens. In many cases, a macroscopic pump is used to generate the pressure. Here, we use a multifunctional LTCC substrate, which consists of two cavities. A micro-fluidic network allows their independent filling. For the actuation, the actuating cavity is filled with air and the optical cavity is filled with immersion oil. If the actuating cavity is heated by screen-printed resistors, the fluid expands and a pressure is transmitted to the optical cavity via a micro-fluidic channel. The optical cavity is covered with a glass chip and a membrane chip, respectively. We use 500 nm thick membranes of aluminum nitride (AlN), which have a 3 mm diameter and are fabricated using technologies of silicon based micro-electro-mechanical systems. With 6 W electrical heating power a temperature increase of 100 K within the actuating cavity is achieved. The generated pressure causes a membrane deflection in the optical cavity of about 30 μm. The thermal actuation is investigated using thermal imaging. By heating the actuating cavity, the optical cavity also heats up, but no temperature gradients along the silicon chip is found. Optical experiments show the imaging capability of the lens and confirm a tunable refractive power of 0..17 dpt.
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Puneeth, K. B., and K. N. Seetharamu. "Analysis, Design, and Optimization of Thermal In-Plane Microactuator—Chevron Type." Journal of Microelectronics and Electronic Packaging 8, no. 3 (July 1, 2011): 102–9. http://dx.doi.org/10.4071/imaps.0296.
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A predictive model of thermal actuator behavior has been developed and validated that can be used as a design tool to customize the performance of an actuator to a specific application. Modeling thermal actuator behavior requires the use of two sequentially or directly coupled models, the first to predict the temperature increase of the actuator due to the applied voltage and the second to model the mechanical response of the structure due to the increase in temperature. These models have been developed using ANSYS for both thermal response and structural response. Consolidation of FEA (finite element analysis) results has been carried out using an ANN (artificial neural network) in MATLAB. It is seen that an ANN can be successfully employed to interpolate and predict FEA results, thus avoiding necessity of running FEA code for every new case. Furtheroptimization of geometry for maximum actuation length has been carried out using a GA (genetic algorithm) in MATLAB. The results of the GA were verified against the ANN and FEA results.
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Hossain, Alamgir, and Md Arifur Rahman. "Comparative Analysis among Single-Stage, Dual-Stage, and Triple-Stage Actuator Systems Applied to a Hard Disk Drive Servo System." Actuators 8, no. 3 (September 3, 2019): 65. http://dx.doi.org/10.3390/act8030065.
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In modern times, the design and optimization of different actuator systems for controlling a high-precision position control system represent a popular interdisciplinary research area. Initially, only single-stage actuator systems were used to control most of the motion control applications. Currently, dual-stage actuation systems are widely applied to high-precision position control systems such as hard disk drive (HDD) servo systems. In the dual-stage system, a voice coil motor (VCM) actuator is used as the primary stage and a piezoelectric micro-actuator is applied as the secondary stage. However, a dual-stage control architecture does not show significant performance improvements to achieve the next-generation high-capacity HDD servo system. Research continues on how to fabricate a tertiary actuator for a triple-stage HDD servo system. A thermal positioning controller (TPC) actuator is considered promising as the tertiary stage. The triple-stage system aims to achieve greater bandwidth, track density, and disk speed, with minimum sensitivity and greater error minimization. In this work, these three actuation systems with different combinations of proportional plus integral (PI), proportional plus derivative (PD), and proportional plus integral plus derivative (PID) controller, lag-lead controller, lag filter, and inverse lead plus a PI controller were designed and analyzed through simulation to achieve high-precision positioning. The comparative analyses were done on the MATLAB/Simulink simulation platform.
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Hwang, Inwook, Seongcheol Mun, Hyungcheol Shin, and Sungryul Yun. "A NIR-Light-Driven Twisted and Coiled Polymer Actuator with a PEDOT-Tos/Nylon-6 Composite for Durable and Remotely Controllable Artificial Muscle." Polymers 14, no. 3 (January 21, 2022): 432. http://dx.doi.org/10.3390/polym14030432.
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In this paper, we proposed a novel light-driven polymer actuator that could produce remotely controllable tensile stroke in response to near infrared (NIR) light. The light-driven polymer actuator was composed of a twisted and coiled nylon-6 fiber (TCN) and a thin poly(3,4-ethylenedioxythiophene) doped with p-toluenesulfonate (PEDOT-Tos) layer. By adopting dip-coating methodology with thermal polymerization process, we constructed a thin and uniform PEDOT-Tos layer on the surface of the three-dimensional TCN structure. Thanks to the PEDOT-Tos layer with excellent NIR light absorption characteristic, the NIR light illumination via a small LEDs array allowed the multiple PEDOT-Tos coated TCN actuators to be photo-thermally heated to a fairly consistent temperature and to simultaneously produce a contractile strain that could be modulated as high as 8.7% with light power. The actuation performance was reversible without any significant hysteresis and highly durable during 3000 cyclic operations via repetitive control of the LEDs. Together with its simple structure and facile fabrication, the light-driven actuator can lead to technical advances in artificial muscles due to its attractive benefits from remote controllability without complex coupled instruments and electromagnetic interference.
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Ali, Abid, R. A. Azim, U. S. Khan, A. A. Syed, and U. Izhar. "Design, Simulation and Optimization of Electrothermal Micro Actuator." Applied Mechanics and Materials 229-231 (November 2012): 1939–43. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.1939.
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This work presents the design and optimization of out of plane electrothermal MEMS actuators. The proposed concept is capable of generating large out of plane displacement at low driving power and a low actuation temperature. The performance of this actuator is evaluated and simulated in ANSYS. The out of plane displacement of 291µm at a temperature increase of 135°C from ambient has been achieved with the applied power of 2.7mW(0.7V). Moreover, a thermal time constant of 5.6ms and a frequency of 85Hz is accomplished for this actuator.
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Lin, Chun-Ying, and Jin-Chen Chiou. "Design, fabrication and actuation of four-axis thermal actuating image stabiliser." Micro & Nano Letters 6, no. 7 (2011): 549. http://dx.doi.org/10.1049/mnl.2011.0100.
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ZHENG, Hao, Hua LIANG, Jie CHEN, Haohua ZONG, Xiangzhe MENG, Like XIE, and Yinghong LI. "Experimental study on plasma actuation characteristics of nanosecond pulsed dielectric barrier discharge." Plasma Science and Technology 24, no. 1 (December 8, 2021): 015505. http://dx.doi.org/10.1088/2058-6272/ac35a3.
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Abstract Combining high-speed schlieren technology and infrared imaging technology, related research has been carried out on the influence of parameters such as actuation voltage, repetition frequency, and electrode size of an actuator on the discharge characteristics, induced flow field characteristics, and thermal characteristics of nanosecond pulsed dielectric barrier discharge. The results show that increasing the value of the actuation voltage can significantly increase the actuation intensity, and the plasma discharge area is significantly extended. Increasing the repetition frequency can increase the number of discharges per unit time. Both will cause more energy input and induce more changes in the flow field. The effect of temperature rise is more significant. The width of the covered electrode will affect the potential distribution during the discharge process, which in turn will affect the extension process of the plasma discharge filament. Under the same actuation intensity, the wider the covered electrode, the larger range the induced flow field and temperature rise is. Preliminary experimental analyses of high-frequency actuation characteristics, temperature field characteristics, flow field characteristics and actuation parameter settings provide support for the parameter selection and partial mechanism analysis of plasma anti-icing.
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Watanabe, Masashi, Naoko Wakimoto, Toshihiro Hirai, and Mikito Yokoyama. "Thermal switching of the actuation ability of an electroactive polymer actuator." Journal of Applied Polymer Science 95, no. 6 (2005): 1566–70. http://dx.doi.org/10.1002/app.21365.
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Xiang, Chaoqun, Jianglong Guo, Rujie Sun, Andrew Hinitt, Tim Helps, Majid Taghavi, and Jonathan Rossiter. "Electroactive Textile Actuators for Breathability Control and Thermal Regulation Devices." Polymers 11, no. 7 (July 18, 2019): 1199. http://dx.doi.org/10.3390/polym11071199.
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Smart fabrics offer the potential for a new generation of soft robotics and wearable technologies through the fusion of smart materials, textiles and electrical circuitries. Conductive and stretchable textiles have inherent compliance and low resistance that are suitable for driving artificial muscle actuators and are potentially safer electrode materials for soft actuation technologies. We demonstrate how soft electroactive actuating structures can be designed and fabricated from conducting textiles. We first quantitatively analyse a range of stretchable conductive textiles for dielectric elastomer actuators (DEAs). We found that conductive-knit textiles are more suitable for unidirectional DEA applications due to the largest difference (150%) in principle strain axes, whereas isotropic textiles are more suited to bidirectional DEA applications due to the smallest (11.1%) principle strain difference. Finally, we demonstrate controllable breathability through a planar e-textile DEA-driven skin and show thermal regulation in a wearable prototype that exploits soft actuation and kirigami.
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Wang, D. W., H. S. Tzou, S. M. Arnold, and H. J. Lee. "Control of Static Shape, Dynamic Oscillation, and Thermally Induced Vibration of Nozzles." Journal of Pressure Vessel Technology 128, no. 3 (August 23, 2005): 357–63. http://dx.doi.org/10.1115/1.2217968.
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Static shape actuation and dynamic control of nozzles can improve their performance, accuracy, reliability, etc. A new curved laminated piezothermoelastic hexahedral finite element is formulated based on the layerwise constant shear angle theory and it is used for modeling and analysis of piezothermoelastic conical shell structures subjected to control voltages for static shape actuation and dynamically and thermally induced vibration controls. Free vibration characteristics of an elastic truncated conical shell nozzle with fixed-free boundary conditions are studied using the new finite element. Both frequencies and mode shapes are accurately computed and compared favorably with available experimental and other numerical data. This study is then extended to evaluate control effectiveness of the conical shell with laminated piezoelectric layers. Static shape control is achieved by an applied electric potential. Vibration sensing and control are carried out using the negative velocity control scheme. Control of thermal excitation is also investigated. Analysis data suggest that the dynamic behavior and control characteristics of conical shells are quite complicated due to the coupled membrane and bending effects participating in the responses. To improve control effectiveness, segmentation and/or shaping of sensor and actuator layers need to be further investigated.
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Ye, Chao, and Xian Xiang Chen. "A MEMS-Based Electrostatic Field Sensor Using Out-of-Plane Thermal Actuation." Key Engineering Materials 609-610 (April 2014): 921–26. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.921.
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In this paper, we report a MEMSbased electrostatic field sensor (EFS) using out-of-plane thermal actuation. The EFS mainly consists of shuttles, sensing electrodes, and clamp-clamp beams. The clamp-clamp beam with a hump is treated as thermal actuator to drive the shuttle, which is to modulate the external electrostatic field. The EFS was fabricated by a standard surface micromachining process and the area of the EFS is less than 2.5mm×2.5mm. The EFS has been tested and achieved a resolution of 60V/m.
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Xu, Xiang Rong, Dong Qing Shi, Fu Qiang Chen, and Xin Qiang Pan. "A Mathematical Model for Electrostatic Actuators Operation with Multilayer Metallic Strip." Applied Mechanics and Materials 201-202 (October 2012): 508–12. http://dx.doi.org/10.4028/www.scientific.net/amm.201-202.508.
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This paper presents a mathematical model to simulate the actuation of a multilayer metallic strip. The model computes the radius of curvature of the actuator when it curls because of difference in thermal coefficient of the different metals used in the strip. The mathematical model for simulating the radius of curvature is based on the earlier work by Timoshenko [4], and Jianyu Fu[5]. The radius of curvature computed is used to calculate the voltage to uncurl the actuator. Numerical experiments were performed on the model and the trends were found to be in agreement with the experimental data.
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Alamin Dow, Ali Badar, Katerina Ivanova, T. Ivanov, and Ivo W. Rangelow. "Design and Fabrication of a Horizontal Thermal Micro-Actuator with Integrated Micro Tweezers." Advances in Science and Technology 54 (September 2008): 378–83. http://dx.doi.org/10.4028/www.scientific.net/ast.54.378.
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Micro tweezers are one of the microsystems technology applications and typically used for handling micro parts and manipulated small objects. Microactuators such as thermal microactuator are mainly used to drive the micro tweezers. This paper present the design, simulation, fabrication and characterization of a new developed two hot arms thermal micro actuator with integrated micro tweezers. The advantages of this new micro actuator with integrated tweezers are, the actuator flexure is not more part of the actuation loop and the electric current only passes through the inner and outer thin hot arms of the actuators which have a high electrical resistance. The actuator efficiency will increases dramatically since all applied power will contribute to the tweezers movement. Further more, a heat dissipation element which act as a heat radiator was introduced to decrease the heat transfer to the tweezers which is strongly required in some applications. The device was fabricated out of silicon substrate by inductively coupled plasma etching process. The device showed very good controlling ability during its operation and a good agreement between experimental and simulation results was achieved.
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Lu, Haibao, Yongtao Yao, and Long Lin. "Temperature sensing and actuating capabilities of polymeric shape memory composite containing thermochromic particles." Pigment & Resin Technology 44, no. 4 (July 6, 2015): 224–31. http://dx.doi.org/10.1108/prt-06-2014-0046.
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Purpose – This paper aims to create and to study multifunctional shape memory polymer (SMP) composites having temperature-sensing and actuating capabilities by embedding thermochromic particles within the polymer matrix. Design/methodology/approach – The multifunctional materials were fabricated following a process consisting of blending (of the thermochromic particles and the SMP at various ratios), mixing, degasing, moulding and thermal curing, prepared by incorporating thermochromic particles within the polymer. The effect of the thermochromic particles on the thermomechanical properties and thermally responsive shape memory effect of the resulting multifunction SMP composites were characterised and interpreted. Findings – It was found that exposure of the composites to temperatures above 70°C led to a pronounced change of their colour that was recorded by the thermal and electrical actuation approaches and was reproducibly reversible. It was also found that the colour of the composites was independent of the mechanical state of the SMP. Such effects enabled monitoring of the onset of the set/release temperature of the SMP matrix. Furthermore, the combination of thermochromic additive and the SMP resulted in significantly improved thermomechanical strength, absorption of infrared radiation and the temperature distribution of the SMP composites. Research limitations/implications – The temperature-sensing and actuating capabilities of the polymeric shape memory composites developed through this study will help to extend the field of potential applications of such composites to fields including sensors, actuators, security labels and information dissemination, where colour indication is an advantageous feature. Originality/value – The SMP composites capable of temperature sensing and actuating are novel.
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Higueras-Ruiz, Diego R., Michael W. Shafer, and Heidi P. Feigenbaum. "Cavatappi artificial muscles from drawing, twisting, and coiling polymer tubes." Science Robotics 6, no. 53 (April 21, 2021): eabd5383. http://dx.doi.org/10.1126/scirobotics.abd5383.
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Compliant, biomimetic actuation technologies that are both efficient and powerful are necessary for robotic systems that may one day interact, augment, and potentially integrate with humans. To this end, we introduce a fluid-driven muscle-like actuator fabricated from inexpensive polymer tubes. The actuation results from a specific processing of the tubes. First, the tubes are drawn, which enhances the anisotropy in their microstructure. Then, the tubes are twisted, and these twisted tubes can be used as a torsional actuator. Last, the twisted tubes are helically coiled into linear actuators. We call these linear actuators cavatappi artificial muscles based on their resemblance to the Italian pasta. After drawing and twisting, hydraulic or pneumatic pressure applied inside the tube results in localized untwisting of the helical microstructure. This untwisting manifests as a contraction of the helical pitch for the coiled configuration. Given the hydraulic or pneumatic activation source, these devices have the potential to substantially outperform similar thermally activated actuation technologies regarding actuation bandwidth, efficiency, modeling and controllability, and practical implementation. In this work, we show that cavatappi contracts more than 50% of its initial length and exhibits mechanical contractile efficiencies near 45%. We also demonstrate that cavatappi artificial muscles can exhibit a maximum specific work and power of 0.38 kilojoules per kilogram and 1.42 kilowatts per kilogram, respectively. Continued development of this technology will likely lead to even higher performance in the future.
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Luqman, Mohammad, Arfat Anis, Hamid M. Shaikh, Saeed M. Al-Zahrani, and Mohammad Asif Alam. "Development of a Soft Robotic Bending Actuator Based on a Novel Sulfonated Polyvinyl Chloride–Phosphotungstic Acid Ionic Polymer–Metal Composite (IPMC) Membrane." Membranes 12, no. 7 (June 25, 2022): 651. http://dx.doi.org/10.3390/membranes12070651.
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This work presents the development of a cost-effective electric-stimulus-responsive bending actuator based on a sulfonated polyvinyl chloride (SPVC)–phosphotungstic acid (PTA) ionic polymer–metal composite (IPMC), using a simple solution-casting method followed by chemical reduction of platinum (Pt) ions as an electrode. The characterizations of the prepared IPMC were performed using Fourier-transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), X-ray diffraction (XRD) techniques, Thermogravimetric analysis (TGA), and Energy-dispersive X-ray (EDX) analysis. Excellent ion-exchange capacity (IEC) and proton conductivity (PC), with values of ca. 1.98 meq·g−1and ca. 1.6 mS·cm−1, respectively, were observed. The water uptake (WU) and water loss (WL) capacities of the IPMC membranes were measured at 25 °C, and found to have maxima of ca. 48% for 10 h, and ca. 36% at 6 V DC for almost 9 min, respectively. To analyze the actuation performance of the developed membrane, tip displacement and actuation force measurements were conducted. Tip displacement was found to be ca. 15.1 mm, whereas bending actuation was found to be 0.242 mN at 4 V DC. The moderate water loss, good proton conductivity (PC), high thermal stability, and good electrochemical properties of the developed IPMC membrane actuator position it as a cost-effective alternative to highly expensive conventional perfluorinated polymer-based actuators.
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Panda, Satyajit. "Performance of a short piezoelectric fiber–reinforced composite actuator in vibration control of functionally graded circular cylindrical shell." Journal of Intelligent Material Systems and Structures 27, no. 20 (July 28, 2016): 2774–94. http://dx.doi.org/10.1177/1045389x16641219.
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For improved flexibility and conformability of piezoelectric fiber–reinforced composite actuator, it is reconstructed in a recent study by the use of short piezoelectric fibers (short piezoelectric fiber–reinforced composite) instead of continuous fibers (continuous piezoelectric fiber–reinforced composite). This modification facilitates its application in short piezoelectric fiber–reinforced composite layer form instead of continuous piezoelectric fiber–reinforced composite patch form particularly in case of host structures with highly curved boundary surfaces. But the corresponding change in actuation capability is a major issue for potential application of short piezoelectric fiber–reinforced composite that is studied in this work through the control of vibration of a functionally graded circular cylindrical shell under thermal environment. First, an arrangement of continuous piezoelectric fiber–reinforced composite actuator patches over the host shell surface is presented with an objective of controlling all modes of vibration. Next, the use of short piezoelectric fiber–reinforced composite actuator layer for similar control activity is demonstrated through an arrangement of electrode patches over its surfaces. Subsequently, an electric potential function is assumed for the consideration of electrode patches and a geometrically nonlinear coupled thermo-electro-mechanical incremental finite element model of the harmonically excited overall functionally graded shell is developed. The numerical results reveal actuation capability of short piezoelectric fiber–reinforced composite actuator layer with reference to that of the existing continuous piezoelectric fiber–reinforced composite/monolithic piezoelectric actuator patches. The effects of temperature, size of electrode patches, properties of piezoelectric fiber–reinforced composite, and functionally graded properties on the control activity of short piezoelectric fiber–reinforced composite/continuous piezoelectric fiber–reinforced composite actuator are also presented.
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Tang, Xianzhi, Huaqiang Li, Teng Ma, Yang Yang, Ji Luo, Haidan Wang, and Pei Jiang. "A Review of Soft Actuator Motion: Actuation, Design, Manufacturing and Applications." Actuators 11, no. 11 (November 14, 2022): 331. http://dx.doi.org/10.3390/act11110331.
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Compared with traditional rigid robots, soft robots have high flexibility, low stiffness, and adaptability to unstructured environments, and as such have great application potential in scenarios such as fragile object grasping and human machine interaction. Similar to biological muscles, the soft actuator is one of the most important parts in soft robots, and can be activated by fluid, thermal, electricity, magnet, light, humidity, and chemical reaction. In this paper, existing principles and methods for actuation are reviewed. We summarize the preprogrammed and reprogrammed structures under different stimuli to achieve motions such as bending, linear, torsional, spiral. and composite motions, which could provide a guideline for new soft actuator designs. In addition, predominant manufacturing methods and application fields are introduced, and the challenges and future directions of soft actuators are discussed.
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Cao, Yang, and Jingyan Dong. "Fabrication, modeling, and characterization of soft twisting electrothermal actuators with directly printed oblique heater." Journal of Micromechanics and Microengineering 32, no. 3 (January 21, 2022): 035001. http://dx.doi.org/10.1088/1361-6439/ac4956.
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Abstract Soft electrothermal actuators have drawn extensive attention in recent years for their promising applications in biomimetic and biomedical areas. Most soft electrothermal actuators reported so far demonstrated uniform bending deformation, due to the deposition based fabrication of the conductive heater layer from nanomaterial-based solutions, which generally provides uniform heating capacity and uniform bending deformation. In this paper, a soft electrothermal actuator that can provide twisting deformation was designed and fabricated. A metallic microfilament heater of the soft twisting actuator was directly printed using electrohydrodynamic (EHD) printing, and embedded between two structural layers, a polyimide film and a polydimethylsiloxane layer, with distinct thermal expansion properties. Assisted by the direct patterning capabilities of EHD printing, a skewed heater pattern was designed and printed. This skewed heater pattern not only produces a skewed parallelogram-shaped temperature field, but also changes the stiffness anisotropy of the actuator, leading to twisting deformation with coupled bending. A theoretical kinematic model was built for the twisting actuator to describe its twisting deformation under different actuation effects. Based on that model, influence of design parameters on the twisting angle and motion trajectory of the twisting actuator were studied and validated by experiments. Finite element analysis was utilized for the thermal and deformation analysis of the actuator. The fabricated twisting actuator was characterized on its heating and twisting performance at different supply voltages. Using three twisting actuators, a soft gripper was designed and fabricated to implement pick-and-place operations of delicate objects.
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Kim, Cheol, and Dong Yeub Lee. "Design Optimization of a Curved Actuator with Piezoelectric Fibers." International Journal of Modern Physics B 17, no. 08n09 (April 10, 2003): 1971–75. http://dx.doi.org/10.1142/s0217979203019964.
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Piezoelectric Fiber Composite with Interdigitated Electrodes (PFCIDE) was previously introduced as an alternative to monolithic wafers with conventional electrodes for applications of structural actuation. This paper is an investigation into the performance improvement of piezoelectric fiber composite actuators by optimizing the stacking sequence and changing the matrix material. This paper presents the numerical optimization of a piezoelectric fiber/piezoelectric matrix composite actuator with IDE (PFPMIDE). Various concepts from different backgrounds, including three-dimensional linear elastic and dielectric theories, have been incorporated into the present linear piezoelectric model. To see the structural responses of the actuator integrated with the PFPMIDE, three dimensional finite element formulations were derived. Numerical analyses show larger center displacement of the curved actuator with the PFPMIDE due to optimization of the piezoelectric fiber angles. This paper presents the concept of a curved actuator that occurs naturally via thermal residual stress during the curing process, as well as the optimization of the maximum curved actuator displacement, which is accomplished using the Davidon-Fletcher-Powell (DFP) method.
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Alexandru, Cătălin. "Optimizing the mechanical device of a mono-axial sun tracking mechanism." MATEC Web of Conferences 184 (2018): 01001. http://dx.doi.org/10.1051/matecconf/201818401001.
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The paper deals with the dynamic optimization of the mechanical device for a mono-axial sun tracking system, with application for photovoltaic and solar-thermal systems, which convert the solar radiation in electrical or respectively thermal energy. The actuating of the mono-axial tracking mechanism is carried out by using a linear actuator, the optimization study intending to determine the optimal configuration of the mechanism with the aim to minimize the motor force developed by actuator in order to perform the imposed step-by-step tracking algorithm (motion law). The design variables in the optimal design process are represented by the global coordinates of the connection points of the linear actuator to the adjacent parts (the solar panel and the fixed support). The optimization study is conducted in virtual prototyping environment.
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Razzaq, M. Yasar, M. Behl, and A. Lendlein. "Thermally-Induced Actuation of Magnetic Nanocomposites Based on Oligo(ω-Pentadecalactone) and Covalently Integrated Magnetic Nanoparticles." MRS Advances 3, no. 63 (2018): 3783–91. http://dx.doi.org/10.1557/adv.2018.613.
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AbstractThe incorporation of inorganic particles in a polymer matrix has been established as a method to adjust the mechanical performance of composite materials. We report on the influence of covalent integration of magnetic nanoparticles (MNP) on the actuation behavior and mechanical performance of hybrid nanocomposite (H-NC) based shape-memory polymer actuators (SMPA). The H-NC were synthesized by reacting two types of oligo(ω-pentadecalactone) (OPDL) based precursors with terminal hydroxy groups, a three arm OPDL (3AOPDL, Mn = 6000 g mol·1-1) and an OPDL (Mn =3300 g · mol-1) coated magnetite nanoparticle (Ø = 10 ± 2 nm), with a diisocyanate. These H-NC were compared to the homopolymer network regarding the actuation performance, contractual stress (σcontr) as well as thermal and mechanical properties. The melting range of the OPDL crystals (ΔTm,OPDL) was shifted in homo polymer networks from 36 °C – 76 °C to 41°C – 81 °C for H-NC with 9 wt% of MNP content. The actuators were explored by variation of separating temperature (Tsep), which splits the OPDL crystalline domain into actuating and geometry determining segments. Tsep was varied in the melting range of the nanocomposites and the actuation capability and contractual stress (σcontr) of the nanocomposite actuators could be adjusted. The reversible strain (εrev) was decreased from 11 ± 0.3% for homo polymer network to 3.2±0.3% for H-NC9 with 9 wt% of MNP indicating a restraining effect of the MNP on chain mobility. The results show that the performance of H-NCs in terms of thermal and elastic properties can be tailored by MNP content, however for higher reversible actuation, lower MNP contents are preferable.
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Mishra, Anand K., Thomas J. Wallin, Wenyang Pan, Patricia Xu, Kaiyang Wang, Emmanuel P. Giannelis, Barbara Mazzolai, and Robert F. Shepherd. "Autonomic perspiration in 3D-printed hydrogel actuators." Science Robotics 5, no. 38 (January 29, 2020): eaaz3918. http://dx.doi.org/10.1126/scirobotics.aaz3918.
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In both biological and engineered systems, functioning at peak power output for prolonged periods of time requires thermoregulation. Here, we report a soft hydrogel-based actuator that can maintain stable body temperatures via autonomic perspiration. Using multimaterial stereolithography, we three-dimensionally print finger-like fluidic elastomer actuators having a poly-N-isopropylacrylamide (PNIPAm) body capped with a microporous (~200 micrometers) polyacrylamide (PAAm) dorsal layer. The chemomechanical response of these hydrogel materials is such that, at low temperatures (<30°C), the pores are sufficiently closed to allow for pressurization and actuation, whereas at elevated temperatures (>30°C), the pores dilate to enable localized perspiration in the hydraulic actuator. Such sweating actuators exhibit a 600% enhancement in cooling rate (i.e., 39.1°C minute−1) over similar non-sweating devices. Combining multiple finger actuators into a single device yields soft robotic grippers capable of both mechanically and thermally manipulating various heated objects. The measured thermoregulatory performance of these sweating actuators (~107 watts kilogram−1) greatly exceeds the evaporative cooling capacity found in the best animal systems (~35 watts kilogram−1) at the cost of a temporary decrease in actuation efficiency.
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Ciobanu, Daniela, Codruta Jaliu, and Radu Saulescu. "Chain Tracking System for Solar Thermal Collector." Applied Mechanics and Materials 658 (October 2014): 35–40. http://dx.doi.org/10.4028/www.scientific.net/amm.658.35.
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The use of renewable energy sources represents a continuous concern for the researchers around the world. The main source of renewable energy, the sun can be used for producing hot water / heating or electric energy, by means of solar collectors. The concentrating solar collectors contain tracking systems for orientation on one or two axes. The tracking system for the elevation motion has to ensure a reduced angular stroke. The mechanism that is usually included in the system structure is of linkage type, being driven by a linear actuator. The mechanism has the advantages of low complexity and reduced cost. In the case of diurnal motion, the angular stroke is larger, being usually obtained with gears or chain drives. The actuation is achieved by motor-reducers with high transmission ratios and costs. In order to reduce the costs, mechanisms containing linkages driven by linear actuators are proposed in literature. These tracking systems have the disadvantage of large overall dimensions. To reduce this disadvantage, the paper proposes a new variant of chain tracking system driven by a linear actuator. Then the proposed tracking system is structurally optimized, process that generates 6 new variants of mechanisms. These solutions eliminate the problems created by the hyperstatical constraints and avoid blocking in case of assembling errors.
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Atsumi, Takenori, Shigeo Nakamura, Irizo Naniwa, and Shuya Nosaki. "C-1-5 Triple-Stage-Actuator System with Thermal Actuator for HDDs." Proceedings of the Conference on Information, Intelligence and Precision Equipment : IIP 2014 (2014): _C—1–5–1_—_C—1–5–6_. http://dx.doi.org/10.1299/jsmeiip.2014._c-1-5-1_.
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Osman, Ibrahim Sufian, and Nasir Ghazi Hariri. "Thermal Investigation and Optimized Design of a Novel Solar Self-Driven Thermomechanical Actuator." Sustainability 14, no. 9 (April 23, 2022): 5078. http://dx.doi.org/10.3390/su14095078.
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As the world moves toward cleaner and greener sources of energy, the use of solar energy appeals the most for countries in the Middle East and North Africa (MENA) region, since they have an abundant amount of solar radiation throughout the year. This paper offers a novel design for a shape memory alloy (SMA) actuator that uses solar energy to trigger thermomechanical behavior. Additionally, the proposed design of the thermomechanical actuator aims to be a piston-based linear actuator covered by a solar heat collector (SHC). Furthermore, the thermal behavior of the actuator has been studied in detail using a simulation-based study under the real-time weather conditions of Dammam city, Kingdom of Saudi Arabia (KSA). The thermal study proves that the optimized design of the thermomechanical actuator has achieved a minimum daily temperature variation of 10 °C, which enables the SMA-based thermomechanical actuator to operate in a daily manner throughout the year. Moreover, the presented numerical results show that the proposed thermomechanical actuator requires a twice-maintenance routine yearly. Additionally, it has been observed that the SHC, which is the central part of the designed thermomechanical actuator, can increase the temperature inside the actuator by about 15 °C more than ambient temperature. The proposed study adds to the body of knowledge a design for a passive, solar-driven, and self-actuating smart thermomechanical SMA actuator that is capable of integration with various solar applications, such as the cleaning and tracking of photovoltaic systems.
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Wang, Zhipeng, Bin He, Xinhua Liu, and Qigang Wang. "Development and modeling of a new ionogel based actuator." Journal of Intelligent Material Systems and Structures 28, no. 15 (January 12, 2017): 2036–50. http://dx.doi.org/10.1177/1045389x16682841.
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Ionic electroactive polymer actuators are expected to be one of the most promising driving mechanisms in the future due to their extraordinary features such as their lightweight, flexibility, and low-energy consumption. Traditional ionic electroactive polymer actuators for example, ionic-polymer metal composites have a problem with durability in open air due to the evaporation of water contained in the polymer electrolytes, resulting in a corresponding loss of performance. Electrolysis of the water at relatively low operating voltages may cause deterioration of these materials. Ionic liquids are more thermally and electrochemically stable than water, with unique advantages including negligible volatility, low melting point and high ionic conductivity, therefore they can be used in the application of ionic electroactive polymer actuators. In this work, a new ionic electroactive polymer actuator based on ionogel is developed, which can be operated at low driving voltage with high electrochemical stability. In order to investigate the actuation mechanism of the actuator, a general model consisting of an equivalent electrical circuit, an electromechanical coupling term and a mechanical beam model is built up to characterize its interrelated electrical, mechanical, and chemical properties. This model explains the relationship between input voltage and bending displacement of the actuator. Theoretical and experimental results are demonstrated and documented to validate the conclusion that the model can effectively predict the actuation response of the material. The geometric scalability of the model is also investigated, giving support to the design of the soft mechanism based on ionogel.
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Brailovski, Vladimir, and Patrick Terriault. "A Systematic Approach to Performance Evaluation of Shape Memory Alloys as Actuator Material." Materials Science Forum 638-642 (January 2010): 2034–39. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.2034.
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This work presents a combined performance evaluation approach for SMAs as actuator material – an approach based on the combination of three testing modes: a) stress-free thermal recovery mode, b) fixed-support stress generation mode and c) constant (or variable) bias-stress recovery mode. Based on this testing, a so-called “design diagram” can be constructed. This diagram demonstrates the mechanical work generation potential of an SMA and therefore represents a must-have tool for the application engineer. Given that the working envelope depends on the material composition, microstructure and number of actuation cycles, this approach allows the selection of an appropriate material and the processing technique that will meet the functional requirements of a specific application. To illustrate the proposed performance evaluation technique, we show how it can be applied to the design of an SMA actuator for a morphing wing.
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Ma, Zhaoqi, and Dan Sameoto. "A Review of Electrically Driven Soft Actuators for Soft Robotics." Micromachines 13, no. 11 (November 1, 2022): 1881. http://dx.doi.org/10.3390/mi13111881.
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In recent years, the field of soft robotics has gained much attention by virtue of its aptness to work in certain environments unsuitable for traditional rigid robotics. Along with the uprising field of soft robotics is the increased attention to soft actuators which provide soft machines the ability to move, manipulate, and deform actively. This article provides a focused review of various high-performance and novel electrically driven soft actuators due to their fast response, controllability, softness, and compactness. Furthermore, this review aims to act as a reference guide for building electrically driven soft machines. The focus of this paper lies on the actuation principle of each type of actuator, comprehensive performance comparison across different actuators, and up-to-date applications of each actuator. The range of actuators includes electro-static soft actuators, electro-thermal soft actuators, and electrically driven soft pumps.
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Wu, Yuwei, Min Yu, Qingsong He, David Vokoun, Guoxiao Yin, Xianrui Xu, and Pengfei Lyu. "Axial Motion Characterization of a Helical Ionic Polymer Metal Composite Actuator and Its Application in 3-DOF Micro-Parallel Platforms." Actuators 10, no. 10 (September 27, 2021): 248. http://dx.doi.org/10.3390/act10100248.
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In this work, a helical ionic polymer metal composite (IPMC) was fabricated by thermal treatment in a mold with helix grooves. The axial actuation behaviors of the helical IPMC actuator were observed, and the electromechanical and electrochemical characteristics were evaluated. The experimental results showed that as the voltage increased and the frequency decreased, the axial displacement, axial force, and electric current of the actuator all increased. Compared with square wave and sinusoidal signals, the actuator exhibited the most satisfactory motion under the direct current (DC) signal. For the electrochemical test, as the scanning rate decreased, the gravimetric specific capacitance increased. Within a suitable voltage range, the actuator was chemically stable. In addition, we coupled the Electrostatics module, Transport of Diluted Species module, and Solid Mechanics module in COMSOL Multiphysics software to model and analyze the helical IPMC actuator. The simulation data obtained were in good agreement with the experimental data. Finally, by using three helical IPMC actuators as driving components, an innovative three-degree-of-freedom (3-DOF) micro-parallel platform was designed, and it could realize a complex coupling movement of pitch, roll, and yaw under the action of an electric field. This platform is expected to be used in micro-assembly, flexible robots, and other fields.
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Chillara, Venkata Siva C., Leon M. Headings, Ryohei Tsuruta, Eiji Itakura, Umesh Gandhi, and Marcelo J. Dapino. "Shape memory alloy–actuated prestressed composites with application to morphing automotive fender skirts." Journal of Intelligent Material Systems and Structures 30, no. 3 (November 23, 2018): 479–94. http://dx.doi.org/10.1177/1045389x18812702.
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This work presents smart laminated composites that enable morphing vehicle structures. Morphing panels can be effective for drag reduction, for example, adaptive fender skirts. Mechanical prestress provides tailored curvature in composites without the drawbacks of thermally induced residual stress. When driven by smart materials such as shape memory alloys, mechanically-prestressed composites can serve as building blocks for morphing structures. An analytical energy-based model is presented to calculate the curved shape of a composite as a function of force applied by an embedded actuator. Shape transition is modeled by providing the actuation force as an input to a one-dimensional thermomechanical constitutive model of a shape memory alloy wire. A design procedure, based on the analytical model, is presented for morphing fender skirts comprising radially configured smart composite elements. A half-scale fender skirt for a compact passenger car is designed, fabricated, and tested. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quick-release latches; the latches reduce actuation time by 95%. The demonstrator is 62% lighter than an equivalent dome-shaped steel fender skirt.
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Dauksher, Richard, Zachary Patterson, and Carmel Majidi. "Characterization and Analysis of a Flexural Shape Memory Alloy Actuator." Actuators 10, no. 8 (August 22, 2021): 202. http://dx.doi.org/10.3390/act10080202.
Full textAbstract:
Shape memory alloys (SMAs) are popular as actuators for use in soft robots due to their high work density and compatibility with miniaturized on-board batteries and power electronics. However, because SMA actuators are activated through electrical Joule heating, they exhibit poor energy efficiency and low actuator frequencies that arise from long cool-down times. Moreover, in the case of SMA wires that are subject to flexural loading, their load capacity and mechanical work output decrease exponentially with decreasing cross-sectional area. In this study, we perform analytic and numerical analyses to examine the thermal and structural design space around a particular class of flexural SMA wire actuators with the intention of increasing actuator operating frequency and actuation forces. Measurements obtained through experimental testing are consistent with theoretical studies of actuator force output and provide additional insight into the efficiency of electrical-to-mechanical energy conversion. Together, the theoretical and experimental studies provide insights that have the potential to inform SMA wire design and usage in soft robotic applications.