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Journal articles on the topic 'Actuator'
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1
Chen, Tiegang, Yan Ke, Shengbin Qiu, Jun Jiang, Qiang Zhang, and Xiaoyong Zhang. "A novel non-embedded, adjustable, and flexible shape memory alloy actuator for variable-area exhaust nozzle actuation." Review of Scientific Instruments 94, no. 2 (February 1, 2023): 025009. http://dx.doi.org/10.1063/5.0127942.
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The actuator is a fundamental component for a variable-area exhaust nozzle. Conventional actuators for variable-area exhaust nozzles are hydraulic actuators and electric motors. However, they are heavy, large, and structurally complex. Shape memory alloys (SMAs) are light, small, structurally simple, and have unique advantages not found in conventional actuators. However, SMA actuators occupy a large space in the radial direction and cannot be fixed to surfaces with different radii of curvature. Moreover, once designed, the actuating displacement of the actuator cannot be adjusted. To solve this problem, this study develops a novel non-embedded, adjustable, and flexible SMA actuator for variable-area exhaust nozzle actuation. An analytical model is presented to predict mechanical performance. Subsequently, experiments of this flexible SMA actuator are conducted to study the mechanical performance. A proof-of-concept, variable-area exhaust nozzle of the aeroengine is designed, fabricated, and tested to obtain the properties of the exhaust nozzle that are actuated by the flexible SMA actuator. In the experiments, the movement trajectory of the exhaust nozzle is captured using an image recognition technique, and the area changes of the exhaust nozzle are calculated. The results show that the actuator is flexible and can be bent at any angle from −90° to +90°. The actuating displacement of the flexible SMA actuator can be adjusted by increasing or decreasing the number of hinged units. In addition, the area change of the exhaust nozzle is 64.4%, exceeding the largest area change of 40% in previous studies on SMA-actuated exhaust nozzles.
2
Rao, K. Venkata, S. Raja, and T. Munikenche Gowda. "On the Actuation Authority of Adaptive Sandwich Beam with Composite Actuators: Coupled Finite Element Analysis." Advanced Materials Research 585 (November 2012): 332–36. http://dx.doi.org/10.4028/www.scientific.net/amr.585.332.
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A two noded active sandwich beam element is formulated by employing layerwise Timoshenko’s beam theory. Displacement continuity conditions are imposed between different layers of the sandwich. This element is used to model an adaptive sandwich beam with macro-fiber composite (MFC) as extension actuator and shear actuated fiber composite (SAFC) as shear actuator. Influence of thickness and volume fraction of the active fiber (PZT-5A and single crystal PMN-PT) in the composite actuators on the actuation performance of the sandwich beam is investigated. Based on several numerical experiments, it is found that the PMN-PT based shear actuators give maximum actuation authority for the volume fraction of the fibers in the range of 80%-85%, whereas in case of PZT-5A based shear actuators the actuation authority remains maximum for the fiber volume fractions 80% and above.
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Elsherif, AR, M. I. Awad, S. A. Maged, and A. Ramzy. "Design and development of dual-acting soft actuator for assistance and rehabilitation of finger flexion and extension." Journal of Physics: Conference Series 2299, no. 1 (July 1, 2022): 012012. http://dx.doi.org/10.1088/1742-6596/2299/1/012012.
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Abstract The powerfulness of Soft robotic systems is relied to the safe performance. In addition to other advantages: the flexibility and deformability. Developing an assistive tool for Hand rehabilitation through soft pneumatic actuated hand gloves is an improved and suitable way for helping post stroke subjects. The Pneumatic network (Pneu-Net) actuators are soft actuators composed of pneumatic chambers actuates when pressurised with air. Dual acting soft pneumatic Pneu-Net actuator is developed as a part for building the glove, the actuator is designed for assisting both finger flexion and extension motions. Pneumatic network (Pneu-net) actuator is developed and design geometry effect is studied, mainly the influence of the dual actuators on each other in addition to the effect of the number of air chambers per each actuator. Design selection based on the finite element analysis and experimental testing, bending angle and energy efficiency parameters in addition to comfort and safe performance are the main criteria of concern.
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Wang, Shuyu, Zhaojia Sun, Shuaiyang Duan, Yuliang Zhao, Xiaopeng Sha, Shifeng Yu, and Lei Zuo. "A Hydrogel-Based Self-Sensing Underwater Actuator." Micromachines 13, no. 10 (October 19, 2022): 1779. http://dx.doi.org/10.3390/mi13101779.
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Soft robots made of hydrogels are suited for underwater exploration due to their biocompatibility and compliancy. Yet, reaching high dexterity and actuation force for hydrogel-based actuators is challenging. Meanwhile, real-time proprioception is critical for feedback control. Moreover, sensor integration to mimic living organisms remains problematic. To address these challenges, we introduce a hydrogel actuator driven by hydraulic force with a fast response (time constant 0.83 s). The highly stretchable and conductive hydrogel (1400% strain) is molded into the PneuNet shape, and two of them are further assembled symmetrically to actuate bi-directionally. Then, we demonstrate its bionic application for underwater swimming, showing 2 cm/s (0.19 BL/s) speed. Inspired by biological neuromuscular systems’ sensory motion, which unifies the sensing and actuation in a single unit, we explore the hydrogel actuator’s self-sensing capacity utilizing strain-induced resistance change. The results show that the soft actuator’s proprioception can monitor the undulation in real-time with a sensitivity of 0.2%/degree. Furthermore, we take a finite-element method and first-order differential equations to model the actuator’s bending in response to pressure. We show that such a model can precisely predict the robot’s bending response over a range of pressures. With the self-sensing actuator and the proposed model, we expect the new approach can lead to future soft robots for underwater exploration with feedback control, and the underlying mechanism of the undulation control might offer significant insights for biomimetic research.
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Liu, Y.-T., and C.-K. Wang. "A study of the characteristics of a one-degree-of-freedom positioning device using spring-mounted piezoelectric actuators." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, no. 9 (May 22, 2009): 2017–27. http://dx.doi.org/10.1243/09544062jmes1422.
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This article presents the actuating performance of a one-degree-of-freedom (DOF) positioning device using spring-mounted piezoelectric (PZT) actuators. To employ a spring with a preset compression, the operational range of a PZT actuator could be simply enlarged, and a sliding table actuated by PZT impact force might feature long stroke and high-precision positioning ability. An experimental set-up consisting of two spring-mounted PZT actuators was configured to examine the actuating characteristics. According to experimental results, a sliding table with a heavy mass of 172 g could be actuated to move with a step motion ranging from 15 nm to 81 μm by only one single actuation of the PZT actuator, and with a maximum travelling speed of 3.47 mm/s by continuous actuation. In addition to experimental examinations, a dynamic model was established and verified as effective in describing the actuating behaviours through numerical examinations.
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Khazravi, M., and A. A. Dehghani-Sanij. "Ionic Polymer-Metal Composite Actuator Behaviour in Two Novel Configurations." Advances in Science and Technology 61 (September 2008): 163–68. http://dx.doi.org/10.4028/www.scientific.net/ast.61.163.
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IPMCs are one of the most promising smart actuators to replace traditional actuators for some specific applications particularly in the micro-nano scales. IPMC actuator’s shape and configuration have a dramatic effect on the actuation parameters. While the behaviour of IPMCs as a single fixed end strip actuator (cantilever) has been widely studied since the early 80’s, its behaviour in other configurations is relatively unknown. This paper presents work carried out in order to reconfigure these actuators for some new applications. The first configuration is when both ends of an IPMC actuator strip are fully constrained, in both the actuator plane and the normal direction. In this case the displacement and force measurements at the mid point of the strip are presented. The results of a series of experiments show the behaviour of the actuator in this configuration and using these results some models have been proposed. The second configuration is when only one end of the strip is fixed and the other end is constrained in the normal direction with respect to the plane of the actuator strip. A series of experiments were also carried out to explore the IPMC actuator behaviour in terms of maximum displacement and force generated in this configuration. The behaviour of the IPMC actuator in these two configurations is also investigated by studying the internal stresses in the IPMC structure.
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Liang, Kang, Chong Li, Yujian Tong, Jiwen Fang, and Wei Zhong. "Design of a Low-Frequency Harmonic Rotary Piezoelectric Actuator." Actuators 10, no. 1 (December 27, 2020): 4. http://dx.doi.org/10.3390/act10010004.
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Piezoelectric actuators usually operate under a high frequency driving signal. Here we report a harmonic rotating piezoelectric actuator by coupling a harmonic wave generator and a friction rotor, in which the actuator can be actuated by a low-frequency sinusoidal signal with positive bias. The harmonic wave is generated by a two-stage magnifying mechanism consisting of a displacement amplifier and a harmonic rod. Applying piezoelectricity theory, the actuator’s output characteristic equations are deduced. What is more, the output characteristics of piezoelectric actuators are tested with the established experimental system. Results show that the generated harmonic displacements can drive the actuator to work normally at a driving voltage of larger than 90 V and the maximum total harmonic displacement of the piezoelectric actuator comes up to 427.6 μm under the driving voltage of 150 V. Meanwhile, the error between the measured and calculated values of the harmonic displacement is less than 7%. Furthermore, the rotational speed of the piezoelectric actuator reaches 5.45 rpm/min at 150 V voltage and 5 Hz driving frequency.
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Lee, Jae Hoon, Bum Soo Yoon, Ji-Won Park, Gunho Song, and Kwang Joon Yoon. "Flexural Deflection Prediction of Piezo-Composite Unimorph Actuator Using Material Orthotropy and Nonlinearity of Piezoelectric Material Layer." Coatings 10, no. 5 (April 29, 2020): 437. http://dx.doi.org/10.3390/coatings10050437.
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Layered piezo-composite unimorph actuators have been studied by many research teams to provide active vibration control of thin-walled aerospace structures, control the shapes of aircraft wing airfoils, and control the fins of small missiles, because they require less space and provide better frequency responses than conventional electro-magnetic motor actuator systems. However, due to the limited actuation strains of conventional piezo-composite unimorph actuators with poly-crystalline piezoelectric ceramic layers, they have not been implemented effectively as actuators for small aerospace vehicles. In this study, a lightweight piezo-composite unimorph actuator (LIPCA-S2) was manufactured and analyzed to predict its flexural actuation displacement. It was found that the actuated tip displacement of a piezo-composite cantilever could be predicted accurately using the proposed prediction model based on the nonlinear properties of the piezoelectric strain coefficient and elastic modulus of a piezoelectric single crystal.
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Sun, Wenjie, Bin Zhao, and Fei Zhang. "Design Analysis and Actuation Performance of a Push-Pull Dielectric Elastomer Actuator." Polymers 15, no. 4 (February 19, 2023): 1037. http://dx.doi.org/10.3390/polym15041037.
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Dielectric elastomer actuation has been extensively investigated and applied to bionic robotics and intelligent actuators due to its status as an excellent actuation technique. As a conical dielectric elastomer actuator (DEA) structure extension, push-pull DEA has been explored in controlled acoustics, microfluidics, and multi-stable actuation due to its simple fabrication and outstanding performance. In this paper, a theoretical model is developed to describe the electromechanical behavior of push-pull DEA based on the force balance of the mass block in an actuator. The accuracy of the proposed model is experimentally validated by employing the mass block in the construction of the actuator as the object of study. The actuation displacement of the actuator is used as the evaluation indication to investigate the effect of key design parameters on the actuation performance of the actuator, its failure mode, and critical failure voltage. A dynamic actuator model is proposed and used with experimental data to explain the dynamic response of the actuator, its natural frequency, and the effect of variables. This work provides a strong theoretical background for dielectric elastomer actuators, as well as practical design and implementation experience.
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Huang, Yan, Fang Wang, Liying Qian, Xiuhua Cao, Beihai He, and Junrong Li. "A fast-response electroactive actuator based on TEMPO-oxidized cellulose nanofibers." Smart Materials and Structures 31, no. 2 (December 20, 2021): 025005. http://dx.doi.org/10.1088/1361-665x/ac4037.
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Abstract Cellulose-based electroactive actuators are promising candidates for biomimetic robots and biomedical applications due to their lightweight, high mechanical strength, and natural abundance. However, cellulose-based electroactive actuators exhibit lower actuation performance than traditional conductive polymer actuators. This work reports a fast-response cellulose-based electroactive actuator based on 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized nanocellulose (TOCNF) film with layered structure fabricated by evaporation, and gold electrodes prepared by ion sputtering. The residual ions during the TEMPO oxidation process and the layered structure due to self-assembly accelerate the ion migration efficiency in actuators. The proposed actuator can reach a tip displacement of 32.1 mm at a voltage of 10 V and deflect 60° in 5 s. After applying a reverse 10 V voltage, the actuator can also be quickly deflected (42.5 mm). In addition, the actuator also shows high electrical actuation performance at low voltage (5 V). The excellent electroactive performance of as-prepared TOCNF/Au enables the feasibility to be applied to actuators.
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Md Ghazaly, Mariam, Tan Aik Choon, Che Amran Aliza, and Sato Kaiji. "Force Characterization of a Rotary Motion Electrostatic Actuator Based on Finite Element Method (FEM) Analysis." Applied Mechanics and Materials 761 (May 2015): 233–37. http://dx.doi.org/10.4028/www.scientific.net/amm.761.233.
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Two types of rotary motion electrostatic actuators were designed and analyzed using Finite Element Method (FEM) analysis. This paper discussed the comparisons and detailed thrust force analysis of the two actuators. Both designs have similar specifications; i.e the number of rotor’s teeth to stator’s teeth ratio, radius and thickness of rotor, and gap between stator and rotor. Two structures were designed & evaluated; (a) Side-Driven Electrostatic Actuator and (b) Bottom-Driven Electrostatic Actuator. The paper focuses on comparing & analyzing the generated electrostatic thrust force for both designs when the electrostatic actuator’s parameters are varied. Ansys Maxwell 3D software is used to design and analyze the generated thrust force of the two rotary motion electrostatic actuators. The FEM analyses have been carried out by (i) varying the actuator size; (ii), varying the actuator thickness and (iii) varying the actuator teeth ratio. The FEM analysis shows that the Bottom-Drive Electrostatic Actuator exhibit greater thrust force, 4931.80μN compared to the Side-Drive Electrostatic Actuator, 240.96μN; when the actuator’s radius is 700μm, thickness is 50μm, gap between the stator and rotor is 2μm and the teeth ratio is 16:12.
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Lemire, Sebastien, Huu Duc Vo, and Michael W. Benner. "Performance Improvement of Axial Compressors and Fans with Plasma Actuation." International Journal of Rotating Machinery 2009 (2009): 1–13. http://dx.doi.org/10.1155/2009/247613.
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This paper proposes the use of plasma actuator to suppress boundary layer separation on a compressor blade suction side to increase axial compressor performance. Plasma actuators are a new type of electrical flow control device that imparts momentum to the air when submitted to a high AC voltage at high frequency. The concept presented in this paper consists in the positioning of a plasma actuator near the separation point on a compressor rotor suction side to increase flow turning. In this computational study, three parameters have been studied to evaluate the effectiveness of plasma actuator: actuator strength, position and actuation method (steady versus unsteady). Results show that plasma actuator operated in steady mode can increase the pressure ratio, efficiency, and power imparted by the rotor to the air and that the pressure ratio, efficiency and rotor power increase almost linearly with actuator strength. On the other hand, the actuator's position has limited effect on the performance increase. Finally, the results from unsteady simulations show a limited performance increase but are not fully conclusive, due possibly to the chosen pulsing frequencies of the actuator and/or to limitations of the CFD code.
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Koo, Ja Choon, Kwang Mok Jung, Min Young Jung, Hyouk Ryeol Choi, Jae Do Nam, and Young Kwan Lee. "Effect of Pre-Strain on the Antagonistically Driven Dielectric Polymer Actuator." Key Engineering Materials 306-308 (March 2006): 1187–92. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.1187.
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Many publications have demonstrated advantages of smart polymer actuators over the traditional electromagnetic transducers. One of the most significant contributions of the polymers might be their soft actuation mechanism. Hence unlike the traditional actuators, there is morphological freedom for actuator construction that benefits production of either small scale complex mechanisms or human-like applications. Although many different actuation paradigms of polymer actuators presented in previous publications, no significant contributions are made for the actual industrial applications. A noble idea for acquiring controllable actuation is antagonistic drive mechanism of dielectric elastomer. The mechanism provides fairly accurate controllable motion and relatively large actuation forces. A strong dependency to pre-strain of the polymer is however one of the major constraints of the actuator driving mechanism. A detailed characterization of pre-strain effects should be done for the successful construction of the actuators. Hence an experimental and theoretical consideration about mutual effects of pre-strain and actuator performance is to be presented in the present work.
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Ma, X., B. Zhou, and S. F. Xue. "Investigation on Actuation Performance of Continuous Fiber Reinforced Piezoelectric Composite Actuator." Journal of Mechanics 36, no. 3 (December 10, 2019): 273–84. http://dx.doi.org/10.1017/jmech.2019.42.
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ABSTRACTIn this paper, a novel continuous fiber reinforced piezoelectric composite (CFRPC) actuator is proposed to improve the stability and reliability of piezoelectric actuators. A piezoelectric driving structure composed of a cantilever beam and the CFRPC actuator is utilized to research the actuation performance of the CFRPC actuator. The expression of the equivalent moment for the CFRPC actuator is obtained using the equivalent load method and electro-mechanical coupling theory. Based on Euler-Bernoulli beam theory, the analytical expression of the deflection for the cantilever beam is derived. The accuracy of the obtained analytical expressions is demonstrated by finite element simulation as well as published experimental results. The actuation performance of the CFRPC actuator is investigated through the analytical expressions of the equivalent moment and deflection. The results show that the key parameters such as driving voltage, fiber volume fraction, cantilever beam height, actuator height, actuator length and actuator position have great influence on the actuation performance of the CFRPC actuator. The CFRPC actuator has good mechanical and electrical properties, and has a wide application prospect in the field of structural shape control.
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Chen, Yiyu, Hao Wu, Rui Li, Shaojun Jiang, Shuneng Zhou, Zehang Cui, Yuan Tao, et al. "High-performance liquid metal electromagnetic actuator fabricated by femtosecond laser." International Journal of Extreme Manufacturing 6, no. 2 (February 21, 2024): 025503. http://dx.doi.org/10.1088/2631-7990/ad23ee.
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Abstract Small-scale electromagnetic soft actuators are characterized by a fast response and simple control, holding prospects in the field of soft and miniaturized robotics. The use of liquid metal (LM) to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness. Despite research efforts, challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance. To address these challenges, we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method. Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber (1.03 kPa), our actuator exhibits an excellent deformation angle (265.25°) and actuation bending angular velocity (284.66 rad·s−1). Furthermore, multiple actuators have been combined to build an artificial gripper with a wide range of functionalities. Our actuator presents new possibilities for designing small-scale artificial machines and supports advancements in ultrafast soft and miniaturized robotics.
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Liu, Fengyu, Li Chen, Jian Yao, Chunhao Lee, Chi-kuan Kao, Farzad Samie, Ying Huang, and Chengliang Yin. "Design, modeling, and analysis of wedge-based actuator with application to clutch-to-clutch shift." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 9 (September 26, 2017): 1149–66. http://dx.doi.org/10.1177/0954407017727178.
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Clutch-to-clutch shift technology is a key enabler for fast and smooth gear shift process for multi gear transmissions. However, conventional hydraulic actuation systems for clutches have drawbacks of low efficiency, oil leakage and inadequate robustness. Electromechanical devices offer potential alternative actuators. In this paper, a novel motor driven wedge-based clutch actuator, featuring self-reinforcement, is proposed. The design concept and physical structure are thoroughly described. Dynamic models for the actuation system and vehicle powertrain are validated by experiments. Upshift and downshift processes at different engine throttle openings, clutch clearances and friction coefficients are discussed. The results show that, the self-reinforcement ratio is tested as 9.6; at the same time, the shift quality is comparable to that of the conventional hydraulic actuated clutch in automatic transmissions in terms of the shift duration (about 1 s) and vehicle jerk (<10 m/s3). Taking advantage of fast response of the actuation DC motor, the wedge-based actuator is robust dealing with uncertain clutch clearance and friction coefficient. Therefore, the wedge-based clutch actuator has potential to provide acceptable performance for clutch-to-clutch shift.
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Dissanayake, D. M. N. T., W. D. C. C. Wijerathne, S. Shakaf, M. A. R. L. Samaraweera, A. U. Asela, and A. K. C. P. Premarathna. "A Spring – Loaded Actuator Developed By DC 3481 Silicone / Polyaniline – Based Dielectric Polymer Film." Journal of Advances in Engineering and Technology 2, no. 1 (September 30, 2022): 74–80. http://dx.doi.org/10.54389/tofn6318.
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Dielectric polymer films play a significant role in soft robotics in actuator development. Silicone and acrylic materials are commonly used for creating dielectric polymer films with superior properties compared to other potential materials such as PVDF and Polyurethane. Published literature reports applying different fillers to enhance the electromechanical response of dielectric polymers. Starting with an already-reported novel dielectric polymer based on polyaniline/DC 3481 silicon, we report the fabrication and characterization of a spring-loaded actuator. Here we developed a simple spring-loaded actuator, and three different designs were used to optimize the actuator design. As per research outcomes, it can be concluded that paper tie-based clamping provides the best configuration for the actuator in terms of high deflection and low tendency to short-circuit. The developed actuator renders the maximum deflection of 4.19 mm at 2 kV voltage, and the actuation time is approximately 115 s. The proposed actuator is superior to many reported actuators in terms of maximum deflection and corresponding voltage. The proposed actuator and the corresponding dielectric polymer thus have potential applications in developing actuators for haptics with comparatively high deflection. KEYWORDS: actuators, dielectric polymers, haptic technology, DC 3481 silicon, spring loaded
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Georges, Thomas, Vladimir Brailovski, and Patrick Terriault. "Design of Active Bias Sma Actuators for Morphing Wing Applications." Advanced Materials Research 409 (November 2011): 627–32. http://dx.doi.org/10.4028/www.scientific.net/amr.409.627.
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Shape Memory Alloys (SMAs) can provide compact and effective actuation for a variety of mechanical systems. Generally speaking, SMA-driven actuator systems can be divided into three subsystems: a) SMA active element, b) the transmission and c) a bias element. In respect to the type of bias, two actuator configurations can be distinguished: passive bias actuators where the SMA active element is coupled with an elastic bias element (spring), and active bias actuators in which two SMA active elements are connected together. This work is focused on designing an SMA actuator using active bias elements for morphing wing applications. Keywords: SMA actuator, active bias, antagonist, design, morphing wing
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Koo, Ja Choon, Hyouk Ryeol Choi, Min Young Jung, Kwang Mok Jung, Jae Do Nam, and Young Kwan Lee. "Design and Control of Three-DOF Dielectric Polymer Actuator." Key Engineering Materials 297-300 (November 2005): 665–70. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.665.
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Smart polymer based actuators have demonstrated various benefits over the traditional electromagnetic or piezoelectric-material actuators. One of the most significant contributions of the polymers is its soft actuation mechanisms. Hence morphological freedom for actuator construction benefits production of either small scale complex mechanisms or human-like applications. Although many actuation paradigms of polymer actuators are presented in various publications, no significant contributions are made for investigation of modeling and control methods of the material. In the present work, a smart polymer based actuator is constructed. It is then modeled and analyzed for feasible control scheme selection.
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Zhao, Gang, Zhuang Zhi Sun, Yang Ge, and Ling Li Li. "Actuation Properties Investigation: A Muscle like Linear Actuator Based on Biopolymer Material: Ionic Polymer Metal Composites." Journal of Biomimetics, Biomaterials and Biomedical Engineering 25 (October 2015): 19–24. http://dx.doi.org/10.4028/www.scientific.net/jbbbe.25.19.
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In this manuscript, a muscle-like linear actuator based on the combination of Bi-IPMC linear actuator unit was developed focusing on the applied requirements in the biomimetic artificial muscles using as the actuators. Subsequently, the muscle-like linear actuator was mainly fabricated by two segmented IPMC film, which is obtained through a special process and the actuation performance of the muscle-like linear actuator was further experimented by the testing platform. The results found our actuator behaved a high displacement performance, and this kind of muscle-like linear actuator has a potential value in the engineering practice.
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Wang, Xu Dong, Heng Wei Chen, Liao Wang, Wen Zhou, and Yi Qing Li. "Design and Analysis of Pneumatic Bending Actuator Used in Soft Robotics." Advances in Science and Technology 105 (April 2021): 194–201. http://dx.doi.org/10.4028/www.scientific.net/ast.105.194.
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Pneumatic soft actuators can change their shapes under pneumatic pressure actuation and are capable of continuous bending. However, the air chambers inside will expand during the actuation process and cause nonlinear problems. Therefore pneumatic actuators are difficulties to model. In this paper, three types of bending actuators with different air chamber shapes are designed and the finite element model (FEM) is developed to simulate the deformation under different air pressure actuation. A prototype of the bending actuator is fabricated and a method to limit the expansion of the air chamber is designed based on the FEM results, which can effectively improve the expansion and the response of the actuator under low air pressure conditions through experimental comparison.
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Kang, Hye Ran, Hae Do Jung, Jang Oo Lee, and Nam Ju Jo. "Actuative Properties of CP Actuator Consisting of Polypyrrole Film and Solid Polymer Electrolyte." Key Engineering Materials 336-338 (April 2007): 341–44. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.341.
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Conducting polymer (CP) actuators undergo volumetric changes due to the movement of dopant ions into the film during the electrical oxidation process. However, it may be an impediment for practical use of polypyrrole actuator that polypyrrole usually requires electrolyte solution for actuation. To solve this problem, solid polymer electrolyte(SPE) was introduced in CP actuator instead of electrolyte solution. And PPy/SPE/PPy electroactive tri-layer actuator was prepared by the electrochemical polymerization of pyrrole and the actuation characteristics were studied. An all-solid actuator, consisting of two polypyrrole films and a solid polymer electrolyte based on polyurethane, clearly showed a reversible displacement in an atmosphere when a voltage was applied.
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Pimpin, Alongkorn, Eakayoot Wongweerayoot, and Werayut Srituravanich. "Two-Step Electroplating Process in Fabrication of Thermal Bimorph Cantilever Actuator for Flow Control Application." Applied Mechanics and Materials 225 (November 2012): 367–71. http://dx.doi.org/10.4028/www.scientific.net/amm.225.367.
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This work proposes a novel and simple fabrication process of a nickel-copper thermal bimorph actuator. This new fabrication process employs only two-step electroplating technique that is easy, cheap and compatible for various materials. In this study, the total thickness of fabricated cantilever actuator is around 80 μm, i.e. 30±10 and 50±10 μm for nickel and copper, respectively, and its length is equal to 22.5 mm. For actuator’s width, it is varied as 258±7, 351±7 and 447±7 μm. After heating by applying current through the actuator’s structure, the actuator bends up due to the elongation mismatch between copper and nickel elements. It is found that the deflection becomes larger for a narrower actuator. From the experiments, the deflection at current of 2.5A for 258±7 μm wide actuator is approximately equal to 4 mm. In addition, the response of all actuators is faster than 1 Hz. With obtained large deflection and fast response, the fabricated actuators are viable to employ for flow control applications.
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Tzou, H. S., and J. H. Ding. "Actuator Placement and Micro-Actuation Efficiency of Adaptive Paraboloidal Shells." Journal of Dynamic Systems, Measurement, and Control 125, no. 4 (December 1, 2003): 577–84. http://dx.doi.org/10.1115/1.1636199.
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Paraboloidal shells of revolution are commonly used in communication systems, precision opto-mechanical systems and aerospace structures. This study is to investigate the precision distributed control effectiveness of adaptive paraboloidal shells laminated with segmented actuator patches. Mathematical models of the paraboloidal shells laminated with distributed actuator layers subjected to mechanical, temperature, and control forces are presented first. Then, formulations of distributed actuating forces with their contributing micro-meridional/circumferential membrane and bending components are derived using an assumed mode shape function. Studies of actuator placements, actuator induced control forces, micro-contributing components, and normalized actuation authorities of paraboloidal shells are carried out. These forces and membrane/bending components basically exhibit distinct modal characteristics influenced by shell geometries and other design parameters. Analyses suggest that the membrane-contributed components dominate the overall control effect. Locations with larger normalized forces indicate the areas with high control efficiencies, i.e., larger induced actuation force per unit actuator area. With limited actuators, placing actuators at those locations would lead to the maximal control effects of paraboloidal shells.
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Addo-Akoto, Reynolds, and Jae-Hung Han. "Bidirectional actuation of buckled bistable beam using twisted string actuator." Journal of Intelligent Material Systems and Structures 30, no. 4 (December 20, 2018): 506–16. http://dx.doi.org/10.1177/1045389x18817830.
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A new actuation mechanism using the twisted string concept to trigger the snap-through of a bistable buckled beam to produce an effective on/off bistable actuator is proposed. The twisted string concept combined with a pin utilizes actuation moment to actuate a bistable beam. The required actuation loads are analytically formulated using the Euler–Bernoulli beam model and solved with the proposed solution algorithm. The actuation mechanism is fabricated to meet the 24.3 N mm actuation requirements. A prototype of the actuator was built, and its performance was evaluated. In a unidirectional actuation, an actuator response time of 104 ms was achieved. The overall response time of the actuator is affected by the length of the string. The twisted string mechanism was also placed in an antagonistic configuration to enable bidirectional actuation. The shape of the input voltage signal also affected the bidirectional performance of the actuator. The actuator produced an actuation bandwidth of 2 and 5 Hz with sine and square input voltages, respectively, while generating 10 mm output displacement.
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Stoyanov, Hristiyan, Guggi Kofod, and Reimund Gerhard. "A Co-Axial Dielectric Elastomer Actuator." Advances in Science and Technology 61 (September 2008): 81–84. http://dx.doi.org/10.4028/www.scientific.net/ast.61.81.
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Dielectric elastomer actuators based on Maxwell-stress induced deformation, are considered for many potential applications where high actuation strain and high energy density are required. They usually rely on a planar actuator configuration, however, a string-like actuator would be less bulky, and more versatile for several applications. In this paper, a co-axial dielectric elastomer actuator that produces relatively high actuation strain is presented. The actuator is manufactured through alternating dip-coating steps with insulating and conductive thin layers. A soluble thermoplastic block-copolymer, SEBS(poly-(styrene-ethylene-butylene-styrene), is used for the dielectric layers as well as for the host material of the compliant electrodes. Electrical conductivity of the electrodes is achieved by incorporation of conductive carbon-black particles in the elastomer matrix. Actuators with a single and with multiple active layers (up to three) have been successfully demonstrated. This geometry is advantageous in that it is compact and can be bundled easily, and should therefore be practical in applications such as “artificial muscles”.
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MOEENFARD, HAMID, ALI DARVISHIAN, and MOHAMMAD TAGHI AHMADIAN. "ANALYTICAL MODELING OF THE EFFECTS OF ELECTROSTATIC ACTUATION AND CASIMIR FORCE ON THE PULL-IN INSTABILITY AND STATIC BEHAVIOR OF TORSIONAL NANO/MICRO ACTUATORS." International Journal of Modern Physics B 27, no. 06 (February 5, 2013): 1350008. http://dx.doi.org/10.1142/s0217979213500082.
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This paper studies the effect of Casimir force on the pull-in instability of electrostatically actuated torsional nano/micro actuators. Dependence of the actuator's pull-in angle and pull-in voltage on several design parameters are investigated and it is found that Casimir force can considerably reduce the stability limits of the torsional actuators. Nonlinear equilibrium equation is solved numerically and analytically using straight forward perturbation expansion method. It is observed that a fourth-order perturbation approximation can precisely model the behavior of a torsional actuator. The results of this paper can be used for safe and stable design of torsional nano/micro actuators.
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Kiani, Gholamreza, Mojtaba Shahi, and Ali Rostami. "Polymer to Electrode Adhesion Enhancement Based on Novel PI/Au (Nanolayer)/Polypyrrole Three-Bending-Beam Actuator Fabrication." Advanced Materials Research 622-623 (December 2012): 556–60. http://dx.doi.org/10.4028/www.scientific.net/amr.622-623.556.
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Novel combined electrochemical and chemical synthesis methods for the preparation of Polypyrrole-based actuators are presented. Polypyrrole (PPy) actuators were electrochemically synthesized and after coating with a thin gold nano-layer, prepared into a Polyethersulfone (PI) substrate. Scanning Tunneling Microscopy (STM) and a potentiostat–galvanostat were used to confirm the actuation of PPy based actuators during the redox process. Three-layer actuator based on polypyrrole as electroactive material, Polyethersulfone as substrate and gold nanolayer in our proposed method have been realized. The structure strength and layer adhesion have been improved. This advancement in conducting polymer actuator technology will impact many engineering fields, where a stable, lightweight and large displacement actuator is needed.
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Ijaz, Salman, Mirza T. Hamayun, Lin Yan, and Cun Shi. "Active fault-tolerant control for vertical tail damaged aircraft with dissimilar redundant actuation system using integral sliding mode control." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 7 (September 15, 2018): 2361–78. http://dx.doi.org/10.1177/0954406218790280.
Full textAbstract:
The research about the dissimilar redundant actuation system has indicated the potential fault-tolerant capability in modern aircraft. This paper proposed a new design methodology to achieve fault-tolerant control of an aircraft equipped with dissimilar actuators and is suffered from vertical tail damage. The proposed design is based on the concept of online control allocation to redistribute the control signals among healthy actuators and integral sliding mode controller is designed to achieve the closed-loop stability in the presence of both component and actuator faults. To cope with severe damage condition, the aircraft is equipped with dissimilar actuators (hydraulic and electrohydraulic actuators). In this paper, the performance degradation due to slower dynamics of electrohydraulic actuator is taken in account. Therefore, the feed-forward compensator is designed for electrohydraulic actuator based on fractional-order control strategy. In case of failure of hydraulic actuator subject to severe damage of vertical tail, an active switching mechanism is developed based on the information of fault estimation unit. Additionally, a severe type of actuator failure so-called actuator saturation or actuator lock in place is also taken into account in this work. The proposed strategy is compared with the existing control strategies in the literature. Simulation results indicate the dominant performance of the proposed scheme. Moreover, the proposed controller is found robust with a certain level of mismatch between the actuator effectiveness level and its estimate.
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Ghosh, Bhaskar, Ravi K. Jain, S. Majumder, SS Roy, and Sumit Mukhopadhyay. "Experimental characterizations of bimorph piezoelectric actuator for robotic assembly." Journal of Intelligent Material Systems and Structures 28, no. 15 (January 13, 2017): 2095–109. http://dx.doi.org/10.1177/1045389x16685441.
Full textAbstract:
Piezoelectric actuator is one of the most versatile types of smart actuators, extensively used in different industrial applications like robotics, microelectromechanical systems, micro-assembly, biological cell handling, self-assembly, and optical component handling in photonics. By applying potential to a piezoelectric actuator, it can produce micro level deflection with large force generation, very fast response, and long-term actuation as compared to other actuators. The design and analysis of the bimorph piezoelectric cantilever using proportional–integral controller are carried out where the bimorph piezoelectric actuator is used as an active actuator for providing the dexterous behavior during robotic assembly. Characterization of bimorph piezoelectric actuator carried out by controlling voltage signal provides steady-state behavior which is verified by conducting experiments. A prototype of micro gripper is also developed which shows the potential of handling small lightweight objects for robotic assembly.
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Nandi, A., S. Neogy, S. Bhaduri, and H. Irretier. "Vibration Attenuation by a Combination of a Piezoelectric Stack and a Permanent Magnet." Shock and Vibration 19, no. 4 (2012): 719–34. http://dx.doi.org/10.1155/2012/358953.
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The present work proposes a non-contact vibration attenuator made up of a permanent magnet mounted on a piezoelectric stack. Two such actuators are made to work simultaneously in a 'twin-actuator' configuration. It is conceived that a controlled change in the gap between the actuator and the structure is capable of attenuation of vibration of the structure. This appropriate change in gap is achieved by controlled motion of the piezoelectric stacks. It is shown that the actuator works as an active damper when the extension and contraction of the actuators are made proportional to the velocity of the beam. The resolution of extension of a piezoelectric stack is in the order of nanometers. Thus in the proposed actuator the force of actuation can be applied with great precision. This actuator is also attractive for its simple constructional feature.
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Slesarenko, Viacheslav, Seiji Engelkemier, Pavel Galich, Dmitry Vladimirsky, Gregory Klein, and Stephan Rudykh. "Strategies to Control Performance of 3D-Printed, Cable-Driven Soft Polymer Actuators: From Simple Architectures to Gripper Prototype." Polymers 10, no. 8 (August 1, 2018): 846. http://dx.doi.org/10.3390/polym10080846.
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The following is a study of the performance of soft cable-driven polymer actuators produced by multimaterial 3D printing. We demonstrate that the mechanical response of the polymer actuator with an embedded cable can be flexibly tuned through the targeted selection of actuator architecture. Various strategies, such as the addition of discrete or periodic stiff inserts, the sectioning of the actuator, or the shifting of the cable channel are employed to demonstrate ways to achieve more controllable deformed shape during weight lifting or reduce the required actuation force. To illustrate these concepts, we design and manufacture a prototype of the soft polymer gripper, which is capable of manipulating small, delicate objects. The explored strategies can be utilized in other types of soft actuators, employing, for instance, actuation by means of electroactive polymers.
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Annaz, Fawaz Yahya, and Malaka Miyuranga Kaluarachchi. "Progress in Redundant Electromechanical Actuators for Aerospace Applications." Aerospace 10, no. 9 (September 7, 2023): 787. http://dx.doi.org/10.3390/aerospace10090787.
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The power to move aircraft control surfaces has advanced from being manually generated (by the pilot and transmitted via rods and links) to electrically transmitted (via wires) to operate control surface actuators. Various hydraulic, electromagnetic, and electromechanical architectures have been developed to provide the necessary power and to maintain the expected redundancy. Numerous aircraft actuator system designs have been proposed in the past decades, but a comprehensive review has yet to be undertaken. This review paper aims to fill this gap by providing a critical review of the actuation system designs developed for a variety of aircraft. The review focuses on aircraft actuator system designs, namely: electrohydraulic actuator systems, electromechanical actuator systems, and the force-fighting effect in redundant actuation systems. The significance and operational principle of each actuator system are critically analysed and discussed in the review. The paper also evaluates the solution proposed to address force-fight equalization (or force-fight cancelation) in force or torqued-summed architectures. Future trends in redundant actuation system development with reduced force-fighting effect in aircraft actuator systems are also addressed.
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JO, NAM-JU, HYUN-OK LIM, MIN-YOUNG PARK, HYUN PARK, IN-WON LEE, and HO-HWAN CHUN. "THE EFFECT OF CARBON FILLER TYPE ON ACTUATION BEHAVIOR OF CONDUCTING POLYMER ACTUATOR." Functional Materials Letters 04, no. 01 (March 2011): 75–78. http://dx.doi.org/10.1142/s1793604711001580.
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Conducting polymer (CP) actuators undergo a volume change as the redox state is changed. The volume change is caused by the movement of counter ions into the film during the electrical oxidation process. In freestanding CP actuators, the electrical resistance of a CP film can produce significant power-supply voltage (IR) drop along its length, which can restrict the actuator performance. To solve this problem, CP nanocomposite with carbon filler was introduced. This study aimed to improve conductivity and ease off the IR drop occurred during the actuation of CP actuator. CP nanocomposite actuator with 3:7 of CB:CNF co-filler content showed the maximum displacement due to the synergy effect, and did not involve IR drop when the length of actuator was 25 mm.
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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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Wang, Wei, Zikuo Zhang, and Zhichun Yang. "Experiment and Modeling on Macro Fiber Composite Stress-Induced Actuation Function Degradation." Applied Sciences 9, no. 21 (November 5, 2019): 4714. http://dx.doi.org/10.3390/app9214714.
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The effect of stress depolarization will cause actuation function degradation of a piezoelectric actuator, which can eventually trigger function failure of the piezoelectric smart structure system. In the present study, we experimentally demonstrate the degradation process of the actuation function of the Macro Fiber Composite (MFC) piezoelectric actuator. Actuation function degradation data of MFC actuators undergoing cyclic loads with four different stress amplitudes have been measured. Based upon the experimental results, the radial basis function (RBF) neural network learning algorithm was adopted to establish a neural network model, in order to predict the actuation function degenerative degree of the MFC actuator, undergoing arbitrary cyclic load within the concerned stress amplitude range. The maximum relative error between the predicted result and our experimental result is 4%.
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Mohamed, M. R., A. A. Roshdy, A. A. Ali, and M. A. Fayed. "Position control of Stewart platform with electric linear actuator." Journal of Physics: Conference Series 2616, no. 1 (November 1, 2023): 012027. http://dx.doi.org/10.1088/1742-6596/2616/1/012027.
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Abstract In recent decades, several technological applications have depended on manipulators like Stewart platform due to its accuracy and precision. Based on actuation type, Stewart platforms could be rotary or linearly actuated. Electric linear actuators are devices commonly consist of DC or AC motors coupled with lead screw or mechanism of gears and spindle which are used to convert rotary motion into linear (push or pull) motion. To increase accuracy and precision and achieve the desired linear actuator response, controllers should be used. The main aspiration of this work is to investigate the feasibility of using PID controllers for position control of Stewart platform with linear actuators. The mathematical model has been derived and the model transfer function has been obtained. To meet the required response of performance characteristics, the PID controller has been designed based on analysis of root-locus. Model simulation analysis has been carried out on both MATLAB and Simulink. For the electric linear actuator, comparison between the obtained response and the results of Ziegler-Nichols tuning method has been discussed on basis of the specifications of the time response. The PID controller parameters for the electric linear actuator has been tested experimentally and compared with simulation results.
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Guo, Liqiang, Ke Li, Guanggui Cheng, Zhongqiang Zhang, Chu Xu, and Jianning Ding. "Design and Experiments of Pneumatic Soft Actuators." Robotica 39, no. 10 (February 17, 2021): 1806–15. http://dx.doi.org/10.1017/s0263574720001514.
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SUMMARYThe soft actuator is made of superelastic material and embedded flexible material. In this paper, a kind of soft tube was designed and used to assemble two kinds of pneumatic soft actuators. The experiment and finite element analysis are used to comprehensively analyze and describe the bending, elongation, and torsion deformation of the soft actuator. The results show that the two soft actuators have the best actuation performance when the inner diameter of the soft tube is 4 mm. In addition, when the twisting pitch of the torsional actuator is 24 mm, its torsional performance is optimized. Finally, a device that can be used in the production line was assembled by utilizing those soft actuators, and some operation tasks were completed. This experiment provides some insights for the development of soft actuators with more complex motions in the future.
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Ijaz, Salman, Mirza Tariq Hamayun, Lin Yan, Hamdoon Ijaz, and Cun Shi. "Adaptive fault tolerant control of dissimilar redundant actuation system of civil aircraft based on integral sliding mode control strategy." Transactions of the Institute of Measurement and Control 41, no. 13 (May 6, 2019): 3756–68. http://dx.doi.org/10.1177/0142331219835589.
Full textAbstract:
In modern aircraft, the dissimilar redundant actuation system is used to resolve the actuator failure issues due to the common cause, thus increasing the system reliability. This paper proposes an adaptive integral sliding mode fault tolerant control strategy to deal with actuator fault/failure in the dissimilar redundant actuation system of civil aircraft. To cope with the unknown actuator faults, the adaptive integral sliding mode controller is designed where the modulation gain is made adaptive to the fault. To deal with the complete failure of certain actuator, the integral sliding mode control is integrated with control allocation scheme and distribute the control input signals to the redundant actuators. The performance of the proposed scheme is tested on the nonlinear model of dissimilar redundant actuation system, where the effect of external airload is accounted during simulations. The effectiveness of the proposed scheme is validated by comparing the simulations with the existing literature.
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Liu, W., and C. R. Rahn. "Fiber-Reinforced Membrane Models of McKibben Actuators." Journal of Applied Mechanics 70, no. 6 (November 1, 2003): 853–59. http://dx.doi.org/10.1115/1.1630812.
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A McKibben actuator consists of an internally pressurized elastic cylindrical tube covered by a shell braided with two families of inextensible fibers woven at equal and opposite angles to the longitudinal axis. Increasing internal pressure causes the actuator to expand radially and, due to the fiber constraint, contract longitudinally. This contraction provides a large force that can be used for robotic actuation. Based on large deformation membrane theory, the actuator is modeled as a fiber-reinforced cylinder with applied inner pressure and axial load. Given the initial shape, material parameters, axial load, and pressure, the analytical model predicts the deformed actuator shape, fiber angle, and fiber and membrane stresses. The analytical results show that for a long and thin actuator the deformed fiber angle approaches 54°44′ at infinite pressure. The actuator elongates and contracts for actuators with initial angles above and below 54°44′ degrees, respectively. For short and thick actuators with initial angles relatively close to 0 deg or 90 deg, however, a fiber angle boundary layer extends to the middle of the actuator, limiting possible extension or contraction. The calculated longitudinal strain and radius change match experimental results to within 5%.
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Kotagond, Aravindkumar D., Somashekhar S. Hiremath, and M. A. Kamoji. "Comparison of Controllers and Actuators Effect on Electro Hydrostatic Actuator." Applied Mechanics and Materials 895 (November 2019): 284–89. http://dx.doi.org/10.4028/www.scientific.net/amm.895.284.
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Hydraulic actuators play a major role in aircraft flight actuation and control. Primary control systems in an aircraft typically control the components that guide an airplane during flight. Electro Hydrostatic Actuators (EHA) is emerging as a viable option for aerospace as well as industrial machine builders. It is an emerging technology which replaces centralized hydraulic system by a self-contained and localized direct drive actuator system. As most of the aircraft applications use symmetric actuator, Symmetric actuator EHA system configuration is considered in most of the literatures. However in case of many industrial applications, asymmetric actuators are being used. The dynamic response that means how fast an actuator reaches a target position is an important criteria for any application. An indigenous experimental setup of EHA system is developed with measuring instruments and sensors that forms a mechatronic system. The Variable Motor and Fixed Pump configuration of EHA is used for experimentation. In this work the load analysis is carried out on asymmetric and symmetric actuators. Similarly the load analysis is carried out on different controllers like Proportional Derivative (PD), Proportional Integral (PI) and Proportional Integral Derivative (PID) over the dynamic response as a output. It is found that symmetric actuator and PD controller gives better results.
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Li, Songqi, and Ping Zhang. "Enhancing Flow Separation Control Using Hybrid Passive and Active Actuators in a Matrix Configuration." Aerospace 11, no. 6 (May 23, 2024): 422. http://dx.doi.org/10.3390/aerospace11060422.
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Efficient control of flow separation holds significant economic promise. This study investigates flow separation mitigation using an experimental platform featuring a combination of passive and active actuators arranged in a matrix configuration. The platform consists of 5 × 6 hybrid actuator units, each integrating a height-adjustable vortex generator and a micro-jet actuator. Inspired by the distributed pattern of V-shaped scales on shark skin, these actuator units are strategically deployed in a matrix configuration to reduce flow separation on a backward-facing ramp. Distributed pressure taps encircling the hybrid actuators monitor the flow state. Parametric analyses examine the effect of different control strategies. By adopting appropriate passive and active actuation patterns, effective pressure recovery on the ramp surface can be achieved. The most significant flow control outcome occurs when the actuators operate under combined active and passive excitation, harnessing the benefits of both control strategies. Particle image velocimetry (PIV) results confirm a notable reduction in flow separation under the best-controlled case. These findings suggest a promising future for flow control devices employing combined passive and active actuation in matrix-like configurations.
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Zhang, Da Wei, Jia Jia Zhang, Rui Wei, Jing Wen Xia, Dan Ni Jiao, and Yun Xiao Pan. "Laser-Induced Shape Memory Polymer Actuator Used in a Deployable Display." Applied Mechanics and Materials 333-335 (July 2013): 1926–29. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.1926.
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Deployable flexible displays attract a great attention recently. The flexible display used on electronic equipment have been developed, which can deploy to reveal a much larger screen or rolled up. However, one of major problems is its actuation of deployment and fixture. In this paper, a deployable display actuated by the SMP actuator is proposed. The shape memory polymer (SMP) actuator, which is considered to be attached to the back side of a flexible display, is used to deploy and fix the flexible display. A new method of laser-induced actuation of SMP actuator is investigated. By this method, the SMP can be induced by infrared light transmitted through a treated optical fiber embedded in the actuator.
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Arrieta, A. F., D. J. Wagg, and S. A. Neild. "Dynamic Snap-through for Morphing of Bi-stable Composite Plates." Journal of Intelligent Material Systems and Structures 22, no. 2 (January 2011): 103–12. http://dx.doi.org/10.1177/1045389x10390248.
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Composite laminate plates designed to have two statically stable configurations have been the focus of recent research, with a particular emphasis on morphing applications. In this article, we consider how external vibration energy can be used to assist with the actuation between stable states. This is of interest in the case when surface bonded macro-fiber composites (MFC) actuators are employed as the actuation system. Typically, these type of actuators have been found to require considerably high voltage inputs to achieve significant levels of actuation authority. Therefore, assisting the actuation process will allow lower voltages and/or stiffer plates to be actuated. Two bi-stable plates with different thickness, [04 - 904]T and [02 - 902]T, are tested. The results show a significant reduction in the force required to change state for the case where dynamic excitation provided by an MFC actuator is used to assist the process. This strategy demonstrates the potential of dynamically assisting actuation as a mechanism for morphing of bi-stable composites.
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Ji, Chen, Minxiu Kong, and Ruifeng Li. "Weight Lifting Trajectory Optimization for Variable Stiffness Actuated Robot." Complexity 2019 (July 18, 2019): 1–12. http://dx.doi.org/10.1155/2019/4872189.
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Variable stiffness actuator is a new actuation of robot which is inspired by motor control of human arm. And it is promising way to exploit the human-like performance and human-like motion. However, due to the mechanical complexity and redundancy of the actuators, it is not trivial to control the variable stiffness actuated robot to perform a human-like motion. In this paper, the weight lifting problem with variable stiffness actuated robot is studied. Then, the original problem is formulated as a constrained optimal control problem and transformed as a general nonlinear programming problem with Gauss pseudospectral method. Simulation studies demonstrate the effectiveness of the proposed method compared with the iLQR approach. Furthermore, the simulations results are presented to show the influence of stiffness variation of variable stiffness actuators on the weight lifting problem.
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Barrett-Gonzalez, Ronald, and Nathan Wolf. "High Speed Microactuators for Low Aspect Ratio High Speed Micro Aircraft Surfaces." Actuators 10, no. 10 (October 13, 2021): 265. http://dx.doi.org/10.3390/act10100265.
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This paper covers a class of actuators for modern high speed, high performance subscale aircraft. The paper starts with an explanation of the challenges faced by micro aircraft, including low power, extremely tight volume constraints, and high actuator bandwidth requirements. A survey of suitable actuators and actuator materials demonstrates that several classes of piezoceramic actuators are ideally matched to the operational environment. While conventional, linear actuation of piezoelectric actuators can achieve some results, dramatic improvements via reverse-biased spring mechanisms can boost performance and actuator envelopes by nearly an order of magnitude. Among the highest performance, low weight configurations are post-buckled precompressed (PBP) actuator arrangements. Analytical models display large deflections at bandwidths compatible with micro aircraft flight control speed requirements. Bench testing of an example PBP micro actuator powered low aspect ratio flight control surface displays +/−11° deflections through 40 Hz, with no occupation of volume within the aircraft fuselage and good correlation between theory and experiment. A wind tunnel model of an example high speed micro aircraft was fabricated along with low aspect ratio PBP flight control surfaces, demonstrating stable deflection characteristics with increasing speed and actuator bandwidths so high that all major aeromechanical modes could be easily controlled. A new way to control such a PBP stabilator with a Limit Dynamic Driver is found to greatly expand the dynamic range of the stabilator, boosting the dynamic response of the stabilator by more than a factor of four with position feedback system engaged.
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Zhu, Yin Long, Hong Pin Zhou, and Hua Ming Wang. "Modeling and Actuation Performance Analysis of Conically-Shaped Dielectric Electroactive Polymer Actuator." Applied Mechanics and Materials 633-634 (September 2014): 250–56. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.250.
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Dielectric elastomer actuators (DEAs) represent one class of electroactive polymers that have already demonstrated excellent performances and show potential applications in many fields. In this paper, we present a simplified conically-shaped dielectric elastomer actuator model to explore the effects of various preloads and actuation voltages on both the actuation displacement and force output of DEA. The strain energy potential of Yeoh is used and the viscoelasticity is also taken into account. Using the developed model, the numerical results of DEA including the actuation displacement, the distribution of the principal stretch ratios and principal stresses in the membrane and the force output can be obtained. With different preloads and actuation voltages, the actuation characteristic of conically-shaped dielectric elastomer actuator is explored experimentally and validates the results determined from the proposed model. The proposed model can be used for the design and optimization of conically-shaped dielectric elastomer actuator.
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Liu, Yonggang, Aoke Zeng, Shuliang Zhang, Ruixiang Ma, and Zhe Du. "An Experimental Investigation on Polarization Process of a PZT-52 Tube Actuator with Interdigitated Electrodes." Micromachines 13, no. 10 (October 18, 2022): 1760. http://dx.doi.org/10.3390/mi13101760.
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The manipulator is the key component of the micromanipulator. Using the axial expansion and contraction properties, the piezoelectric tube can drive the manipulator to achieve micro-motion positioning. It is widely used in scanning probe microscopy, fiber stretching and beam scanning. The piezoceramic tube actuator used to have continuous electrodes inside and outside. It is polarized along the radial direction. There are relatively high polarization voltages, but poor axial mechanical properties. A new tubular actuator is presented in this paper by combining interdigitated electrodes and piezoceramic tubes. The preparation, polarization and mesoscopic mechanical properties were investigated. Using Lead Zirconate Titanate (PZT-52) as a substrate, the preparation process of interdigitated electrodes by screen printing was studied. For initial polarization voltage determination, the local characteristic model of the actuator was extracted and the electric field was analyzed by a finite element method. By measuring the actuator’s axial displacement, we measured the actuator’s polarization effect. Various voltages, times and temperatures were evaluated to determine how polarization affects the actuator’s displacement. Optimal polarization conditions are 800 V, 60 min and 150 °C, with a maximum displacement of 0.88 μm generated by a PZT-52 tube actuator with interdigitated electrodes. PZT-52 tube actuators with a continuous electrode cannot be polarized under these conditions. The maximum displacement is 0.47 μm after polarization at 4 kV. Based on the results, the new actuator has a more convenient polarization process and a greater axial displacement from an application standpoint. It provides technical guidance for the preparation and polarization of the piezoceramic tube actuator. There is potential for piezoelectric tubular actuators to be used in a broader range of applications.
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Xiong, Shaoping, Gabriel Wilfong, and John Lumkes. "Development of a novel high-speed actuation mechanism using a magneto-rheological fluid clutch and its application to a fluid control valve." Journal of Intelligent Material Systems and Structures 30, no. 16 (July 28, 2019): 2502–16. http://dx.doi.org/10.1177/1045389x19862368.
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In many dynamic systems, such as vehicles, engine air and fuel control systems, fluid power systems, industrial robotics, and testing machines, high-speed actuators are necessary to achieve efficient system operation and high bandwidth performance. This article introduces a new actuation mechanism to enable high-speed actuation. The premise for this actuation mechanism is to momentarily couple a moving component (kinetic energy source) with translational components, which is enabled by a coupling/clutch system. The kinetic energy source (flywheel, electric motor, pump or motor shaft, etc.) is intermittently clutched and declutched to produce linear motion. This article presents such an energy coupler actuator using a magneto-rheological fluid clutch, initially focused on an application for high-speed valve actuation. A multi-physics coupled model was developed to evaluate the proposed energy coupler actuator performance. Simulations were conducted to optimize the energy coupler actuator design parameters. A prototype of the magneto-rheological fluid energy coupler actuator based on the optimal design solution was fabricated and experimentally tested, which achieved 1.6-mm stroke in 4.7 ms.
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Wetherhold, Robert, Markus Messer, and Abani Patra. "Optimization of Directionally Attached Piezoelectric Actuators." Journal of Engineering Materials and Technology 125, no. 2 (April 1, 2003): 148–52. http://dx.doi.org/10.1115/1.1555653.
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A directionally attached piezoelectric (DAP) actuator is one method to control the twisting vibration of a plate with high authority. Although insuring proper performance for DAP actuators has been discussed in terms of the control law used, the optimization of the mechanical details of the actuator itself has received little attention. There is an interaction between the actuator and the controlled structure because more actuator material on the structure adds actuation power but also stiffens the structure. The effects of DAP actuator geometric parameters and material properties are explored in a systematic way for the case of a cantilever beam and it is shown that significant improvements in performance are possible. The material property study indicates that an optimum point exists whereby the weight and thus cost can be lowered while improving structure response by using a composite actuator. The actuator thickness, width, orientation angle, and offset from the clamped end have significant effects on structure response. In order of importance, the geometric parameters are: actuator thickness, orientation angle, width and offset. A study of the modal distribution for the structure shows that if the input disturbance that is to be suppressed is modally well characterized, the structure can be efficiently controlled by using more than one independent actuation voltage.