Articles de revues sur le sujet « Mechanical actuators »
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1
Bazghaleh, Mohsen, Steven Grainger et Morteza Mohammadzaheri. « A review of charge methods for driving piezoelectric actuators ». Journal of Intelligent Material Systems and Structures 29, no 10 (11 octobre 2017) : 2096–104. http://dx.doi.org/10.1177/1045389x17733330.
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Piezoelectric actuators are the most commonly used actuators in nanopositioning. They provide excellent operating bandwidth and precision. These actuators are normally driven by voltage amplifiers; however, the relationship of the applied voltage on the actuator and its position is nonlinear and complex due to phenomena such as hysteresis. This adversely influences actuator’s position control which is the core component of nanopositioning. However, the electrical charge applied on a piezoelectric actuator has a significantly less complex relationship with its position. As a result, driving piezoelectric actuators with charge amplifiers has attracted significant attention. In this article, charge driving methods are classified, and their advantages, major issues and the solutions to these issues are critically reviewed.
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Copaci, Dorin, Dolores Blanco et Luis E. Moreno. « Flexible Shape-Memory Alloy-Based Actuator : Mechanical Design Optimization According to Application ». Actuators 8, no 3 (14 août 2019) : 63. http://dx.doi.org/10.3390/act8030063.
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New robotic applications, among others, in medical and related fields, have in recent years boosted research in the development of new actuators in the search for solutions that are lighter and more flexible than conventional actuators. Shape-Memory Alloy (SMA)-based actuators present characteristics that make them an excellent alternative in a wide variety of applications. This paper presents the design, tests (with the control description) and analysis of various configurations of actuators based on SMA wires: flexible SMA actuators, different mechanical design to multiply the displacement and different configurations for actuators with multiple SMA wires. The performance of the actuators has been analyzed using wires of different activation temperatures. The influence of the Bowden sheath of the flexible actuator has been tested, as has the thermal behavior of actuators with several wires. This work has allowed determination of the most effective configuration for the development of a flexible actuator based on SMA, from the point of view of dimensions, efficiency, and work frequency. This type of actuator has been applied in the development of soft robots and light robotic exoskeletons.
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Zhou, Ling, Xue Jin Shen, Zhen Lu Wang et Yi Hu. « Performance Comparison of Typical Electrothermal Actuators ». Key Engineering Materials 562-565 (juillet 2013) : 528–33. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.528.
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As the power producer, the micro actuator is an important part of the micro electro- mechanical system, which is used as the conversion of energy, motion and force producing. In this paper, the mechanical models of three bent beam electrothermal actuators are summarized to make comparison with each other and analyze mechanical performance. For Π-shaped actuators, the tip displacements are proportional to temperature increment and length, having no relationship with the beam width and thickness. However, the displacement of Π-shaped actuators is smaller than the one of V-shaped actuators with the same parameters. For V-shaped actuators, the tip displacements of cascaded V-shaped actuators are larger than the ones of single V-shaped actuators with the same parameters. Especially, cascaded V-shaped actuator with secondary beam having no current has the largest displacement.
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Massey, K. C., J. McMichael, T. Warnock et F. Hay. « Development of mechanical guidance actuators for a supersonic projectile ». Aeronautical Journal 112, no 1130 (avril 2008) : 181–95. http://dx.doi.org/10.1017/s0001924000002128.
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Abstract In this paper, the results of a series of experiments funded by DARPA to determine the feasibility of using small actuators to provide directional control for a supersonic projectile are presented. Controlling the flight of the projectile was accomplished by taking advantage of complex shock-boundary-layer interactions produced by mechanical devices. Experimental tests were conducted at GTRI to screen several control concepts and actuator locations. Further experiments were conducted on a scale projectile in a supersonic stream to investigate the rise time of the forces. Several different mechanical actuators were tested which served to provide guidance for future actuator designs. CFD results were also used to predict the results in flight as well as gain insights into the fluid mechanics involved. Flight tests of a Mach 4 round proved the viability of the guidance actuator.
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Zhang, Yu Fang. « Review of Mechanical Structure of Force Actuator for Optical Astronomical Telescope ». Advanced Materials Research 765-767 (septembre 2013) : 25–28. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.25.
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Reviewed the application of force actuators in the optical astronomical telescopes, and introduced the working principle, mechanical structure, performance requirements and basic components of the force actuators; then compared the advantages and disadvantages of force actuator types which commonly used in astronomical telescopes, finally, propose a outlook of the development trend of the actuator on the great telescope application requirements.
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Gallo, Carlos Alberto, Fernando Lessa Tofoli, Domingos Alves Rade et Valder Steffen. « Piezoelectric actuators applied to neutralize mechanical vibrations ». Journal of Vibration and Control 18, no 11 (26 octobre 2011) : 1650–60. http://dx.doi.org/10.1177/1077546311422549.
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Piezoelectric actuators are widely used in smart structural systems to actively control vibration and noise, and to enhance performance. Because of the highly capacitive nature of these actuators, special power amplifiers, capable of delivering high currents, are required to drive these systems. In this paper, a study to reduce the reactive energy that is necessary in such systems is carried out. This is accomplished by associating the actuator with its capacitive characteristic circuit. Also, non-idealities of the circuit performance are addressed, along with theoretical limits regarding possible power savings and practical difficulties in achieving them. The proposed converter introduces energy to correct the difference of phase between current and voltage that is supplied to the piezoelectric transducer (PZT) actuator. This process is optimized by the introduction of reactive power to the characteristic process of the PZT’s actuator circuit. Therefore the system is supposed to present an electric characteristic that is close to resistive, and is not capacitive any more.
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Liu, Yonggang, Aoke Zeng, Shuliang Zhang, Ruixiang Ma et Zhe Du. « An Experimental Investigation on Polarization Process of a PZT-52 Tube Actuator with Interdigitated Electrodes ». Micromachines 13, no 10 (18 octobre 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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Sardesai, Aditya N., Xavier M. Segel, Matthew N. Baumholtz, Yiheng Chen, Ruhao Sun, Bram W. Schork, Richard Buonocore, Kyle O. Wagner et Holly M. Golecki. « Design and Characterization of Edible Soft Robotic Candy Actuators ». MRS Advances 3, no 50 (2018) : 3003–9. http://dx.doi.org/10.1557/adv.2018.557.
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ABSTRACTOne of the goals of soft robotics is the ability to interface with the human body. Traditionally, silicone materials have dominated the field of soft robotics. In order to shift to materials that are more compatible with the body, developments will have to be made into biodegradable and biocompatible soft robots. This investigation focused on developing gummy actuators which are biodegradable, edible, and tasty. Creating biodegradable and edible actuators can be both sold as an interactive candy product and also inform the design of implantable soft robotic devices. First, commercially available gelatin-based candies were recast into pneumatic actuators utilizing molds. Edible robotic devices were pneumatically actuated repeatedly (up to n=8 actuations) using a 150 psi power inflator. To improve upon the properties of actuators formed from commercially available candy, a novel gelatin-based formulation, termed the “Fordmula” was also developed and used to create functional actuators. To investigate the mechanics and functionality of the recast gummy material and the Fordmula, compression testing and biodegradation studies were performed. Mechanical compression tests showed that recast gummy materials had similar properties to commercially available candies and at low strain had similar behavior to traditional silicone materials. Degradation studies showed that actuation was possible within 15 minutes in a biologically relevant solution followed by complete dissolution of the actuator afterwards. A taste test with elementary aged children demonstrated the fun, edible, and educational appeal of the candy actuators. Edible actuator development was an entry and winning submission in the High School Division of the Soft Robotics Toolkit Design Competition hosted by Harvard University. Demonstration of edible soft robotic actuators created by middle and high school aged students shows the applicability of the Soft Robotics Toolkit for K12 STEM education.
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Wiegand, Roland, Bastian Schmitz, Christian Pylatiuk et Stefan Schulz. « Mechanical Performance of Actuators in an Active Orthosis for the Upper Extremities ». Journal of Robotics 2011 (2011) : 1–7. http://dx.doi.org/10.1155/2011/650415.
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The aim of the project OrthoJacket is to develop a lightweight, portable, and active orthosis for the upper limps. The system consists of two special designed fluidic actuators which are used for supporting the elbow function and the internal rotation of the shoulder. A new design of flexible fluid actuator (FFA) is presented that enables more design options of attaching parts, as it is allowed by conventional actuators with a stationary centre of rotation. This advantage and the inherent flexibility and the low weight of this kind of actuator predestined them for the use in exoskeletons, orthoses, and prostheses. The actuator for the elbow generates a maximum torque of 32 Nm; the internal rotation is supported with 7 Nm. Both actuators support the movement with up to 100% of the necessary power. The shells for the arm and forearm are made of carbon reinforced structures in combination with inflatable cushions.
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Li, Chong, Robert N. Dean et George T. Flowers. « Nonlinear Observability Analysis of Micro-machined Electrostatic Actuators Using Self-Sensing ». Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, DPC (1 janvier 2016) : 001632–62. http://dx.doi.org/10.4071/2016dpc-wp36.
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Micro-machined electrostatic actuators (MEA) like parallel plate actuators (PPAs) and comb drive actuators (GCAs) are commonly used in many applications, including gyroscopes, resonators and RF switches. The detection of an actuators' mechanical motion is desired when they are combined with feedback control techniques, especially when the application requires high performance or is affected by disturbances. The motion can be detected by a variety of sensing techniques, including capacitive, piezoresistive and optical. Electrostatic parallel plate actuators can be modeled as a type of variable capacitor, which depends on the gap between a fixed electrode and a movable electrode. Thus, the displacement of the actuator can be obtained by measuring the capacitance. However, this practical method often requires high frequency excitation signal sources or additional sensing structures. The excitation power source not only affects the performance in the actuator's steady state, but it may also generate harmonics that distort the measurement signals due to the nonlinear characteristics of the actuator. In addition, the information about velocity may not be obtained without specific sensing structures. The additional structures occupy more space in each die, which could increase the cost and size, or decrease the performance. In this study, an estimator with a series resistor configuration is proposed. The estimator can estimate the displacement and velocity by measuring the voltage of the power supply and the voltage across the actuator itself. To evaluate the feasibility, a nonlinear observability analysis is applied. The analysis shows the observability index among different system states. A simulation study verified the proposed theories.
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Jang, Minsu, Jun Sik Kim, Ji-Hun Kim, Do Hyun Bae, Min Jun Kim, Donghee Son, Yong-Tae Kim, Soong Ho Um, Yong Ho Kim et Jinseok Kim. « Surface-Controlled Molecular Self-Alignment in Polymer Actuators for Flexible Microrobot Applications ». Polymers 11, no 4 (23 avril 2019) : 736. http://dx.doi.org/10.3390/polym11040736.
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Polymer actuators are important components in lab-on-a-chip and micromechanical systems because of the inherent properties that result from their large and fast mechanical responses induced by molecular-level deformations (e.g., isomerization). They typically exhibit bending movements via asymmetric contraction or expansion with respect to changes in environmental conditions. To enhance the mechanical properties of actuators, a strain gradient should be introduced by regulating the molecular alignment; however, the miniaturization of polymer actuators for microscale systems has raised concerns regarding the complexity of such molecular control. Herein, a novel method for the fabrication of micro-actuators using a simple molecular self-alignment method is presented. Amphiphilic molecules that consist of azobenzene mesogens were located between the hydrophilic and hydrophobic surfaces, which resulted in a splayed alignment. Thereafter, molecular isomerization on the surface induced a large strain gradient and bending movement of the actuator under ultraviolet-light irradiation. Moreover, the microelectromechanical systems allowed for the variation of the actuator size below the micron scale. The mechanical properties of the fabricated actuators such as the bending direction, maximum angle, and response time were evaluated with respect to their thicknesses and lengths. The derivatives of the polymer actuator microstructure may contribute to the development of novel applications in the micro-robotics field.
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Fumagalli, L., F. Butera et Alberto Coda. « Smartflex NiTi Wires for Shape Memory Actuators ». Advances in Science and Technology 59 (septembre 2008) : 198–206. http://dx.doi.org/10.4028/www.scientific.net/ast.59.198.
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Shape Memory Alloys (SMAs) are active metallic materials classified nowadays as “smart” or “intelligent” materials. One of the main areas of interest is that of actuators. The use of Shape Memory Alloys in actuators offers the opportunity to develop robust, simple and lightweight elements that can represent an alternative to electro-magnetic actuators commonly used in several fields of industrial applications, such as automotive, appliances, etc. The obvious simplicity of mechanical design and minimum number of moved parts is amazing for an actuator. NiTi SMAs demonstrated to have the best combination of properties. Due to its relatively high recovery stress and strain, actuators providing significant force and stroke can be designed. There are perhaps thousands of applications of NiTi-based actuators mentioned in literature and in patents. Successful applications will build on SMA strengths whilst taking into account its weaknesses. SAES Getters S.p.A., thanks to its vertically integrated process and to the scientific and quality approach, developed a NiTi-based wires family which can represent a very good solution for shape memory actuators. The mechanically stabilized SAES Smartflex NiTi actuators show a very sophisticated profile of properties. In this paper the mechanical, thermal and electrical response of these shape memory wires, at diameters ranging from 25 to 500 mm, under different working conditions, simulating the actual operating condition in real actuators, will be examined in depth and discussed, in order to direct the design of the actuator so that the functional properties of the material can be completely exploited. The thermomechanical properties have been investigated and measured by several methods. The most common and useful tests for these commercially available wires will be also described.
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Bi, Zhuming, Bongsu Kang et Puren Ouyang. « Fatigue Analysis of Actuators with Teflon Impregnated Coating—Challenges in Numerical Simulation ». Actuators 10, no 4 (18 avril 2021) : 82. http://dx.doi.org/10.3390/act10040082.
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Actuators are essential components for motion in machines, and warranty service lives are basic specifications of actuators. However, fatigue damage or wear of actuators are very complex and related to many design factors, such as materials properties, surface conditions, loads, and operating temperature. Actuator manufacturers still rely heavily on physical experiments to determine the fatigue lives of actuators. This paper investigates the state-of-the-art of using numerical simulations for fatigue analysis of mechanical actuators. Failure criteria of machine elements are discussed extensively; existing works on using finite element methods for machine element designs are examined to (1) explore the feasibility of using a numerical simulation for fatigue analysis and (2) discuss the technical challenges in practice. Moreover, a systematic procedure is suggested to predict fatigue lives of mechanical actuators with Teflon impregnated hard coatings. A virtual fatigue analysis allows for optimizing a mechanical structure, reducing design verification costs, and shortening the development time of actuators.
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Qiao, Guan, Geng Liu, Zhenghong Shi, Yawen Wang, Shangjun Ma et Teik C. Lim. « A review of electromechanical actuators for More/All Electric aircraft systems ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 232, no 22 (28 décembre 2017) : 4128–51. http://dx.doi.org/10.1177/0954406217749869.
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Conventional hydraulic actuators in aircraft systems are high maintenance and more vulnerable to high temperatures and pressures. This usually leads to high operating costs and low efficiency. With the rapid development of More/All Electric technology, power-by-wire actuators are being broadly employed to improve the maintainability, reliability, and manoeuvrability of future aircraft. This paper reviews the published application and development of the airborne linear electromechanical actuator. First, the general configuration, merits, and limitations of the gear-drive electromechanical actuator and the direct-drive electromechanical actuator are analysed. Second, the development state of the electromechanical actuator testing systems is elaborated in three aspects, namely the performance testing based on room temperature, testing in a thermal vacuum environment, and iron bird. Common problems and tendencies of the testing systems are summarized. Key technologies and research challenges are revealed in terms of fault-tolerant motor, high-thrust mechanical transmission, multidisciplinary modelling, thermal management, and thermal analysis. Finally, the trend for future electromechanical actuators in More/All Electric Aircraft applications is summarized, and future research on the airborne linear electromechanical actuators is discussed.
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Ijaz, Salman, Mirza T. Hamayun, Lin Yan et 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 (15 septembre 2018) : 2361–78. http://dx.doi.org/10.1177/0954406218790280.
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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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Lee, Tae-Hoon, Gun-Ha Yoon, Je-Won Kang et Seung-Bok Choi. « An experimental comparison of the pedestrian safety performances of a spring actuator and a pyrotechnic actuator for deploying an active hood lift system ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 231, no 7 (23 avril 2017) : 973–83. http://dx.doi.org/10.1177/0954407017701534.
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This research experimentally investigates the pedestrian safety performance of an active hood lift system of a passenger vehicle by adopting two different actuators: a spring actuator and a pyrotechnic actuator (gunpowder). After briefly introducing the working principle of the active hood lift system with the two different actuators, experiments to measure the deployment time of the system are carried out to evaluate the pedestrian safety. Subsequently, headform impact tests on the hood are performed to generate the impact force, and hence the mitigation of pedestrian injuries is investigated for the two different actuators. By comparing the measured performances obtained from both actuators, it is shown that the pyrotechnic actuator can provide a faster deployment system time. It is also identified that the spring actuator can provide a better safety performance for protecting adult pedestrians, whereas the safety performance of the pyrotechnic actuator is relatively low. Consequently, the pyrotechnic actuator is redesigned and manufactured to improve its safety performance and tested again. Then, it is shown that the modified pyrotechnic actuator can provide a better protection effect for an adult pedestrian than the spring actuator can.
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Huang, Yan, Fang Wang, Liying Qian, Xiuhua Cao, Beihai He et Junrong Li. « A fast-response electroactive actuator based on TEMPO-oxidized cellulose nanofibers ». Smart Materials and Structures 31, no 2 (20 décembre 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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Yan, W. Y., et A. M. Al-Jumaily. « Feasibility of using an active actuator for two-dimensional vibration abatement in a turning process ». Proceedings of the Institution of Mechanical Engineers, Part K : Journal of Multi-body Dynamics 216, no 4 (1 décembre 2002) : 335–42. http://dx.doi.org/10.1243/146441902320992428.
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This paper presents a simulation model that considers the radial and tangential vibrations and their abatement using active actuators in a turning process. The model is simulated using Simulink in a MATLAB environment to assess the possibility of using an active actuator to reduce vibrations in two directions. Comparison is made between the two orthogonal actuators scenario and the one inclined actuator scenario. The results indicate that vibration reduction using an active inclined actuator is comparable with that using two orthogonal actuators.
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Zhou, Bo, Xiao Ma et Shifeng Xue. « Nonlinear Analysis of Laminated Beams with Braided Fiber Piezoelectric Composite Actuators ». International Journal of Applied Mechanics 12, no 04 (mai 2020) : 2050043. http://dx.doi.org/10.1142/s175882512050043x.
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This paper presents a novel approach for improving the reliability and driving capability of piezoelectric actuators by developing braided fiber piezoelectric composite (BFPC) actuators. The nonlinear analysis of laminated beams integrated with the BFPC actuators under electric load is presented. According to Timoshenko beam theory and von Kármán nonlinear geometric relation, the strain components of the piezoelectric laminated beams are obtained. The nonlinear governing equations of the piezoelectric laminated beams are derived by the Galerkin method and principle of minimum potential energy, and then are solved through the direct iterative method. The accuracy of this method is demonstrated by its comparison with the published results. The driving capability of the BFPC actuator and the existing piezoelectric composite actuator is compared. The influences of the fiber volume fraction, actuator thickness, simply supported beam thickness and applied voltage on the driving capability of the BFPC actuators are discussed through a comprehensive parametric study. The numerical results illustrate that the BFPC actuators with excellent driving capability can effectively control the deformation of smart structures.
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Kedzierski, Jakub, et Eric Holihan. « Linear and rotational microhydraulic actuators driven by electrowetting ». Science Robotics 3, no 22 (19 septembre 2018) : eaat5643. http://dx.doi.org/10.1126/scirobotics.aat5643.
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Microhydraulic actuators offer a new way to convert electrical power to mechanical power on a microscale with an unmatched combination of power density and efficiency. Actuators work by combining surface tension force contributions from a large number of droplets distorted by electrowetting electrodes. This paper reports on the behavior of microgram-scale linear and rotational microhydraulic actuators with output force/weight ratios of 5500, cycle frequencies of 4 kilohertz, <1-micrometer movement precision, and accelerations of 3 kilometers/second2. The power density and the efficiency of the actuators were characterized by simultaneously measuring the mechanical work performed and the electrical power applied. Maximum output power density was 0.93 kilowatt/kilogram, comparable with the best electric motors. At maximum power, the actuator was 60% efficient, but efficiencies were as high as 83% at lower power. Rotational actuators demonstrated a torque density of 79 newton meters/kilogram, substantially more than electric motors of comparable diameter. Scaling the droplet pitch from 100 to 48 micrometers increased power density from 0.27 to 0.93 kilowatt/kilogram, validating the quadratic scaling of actuator power.
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Lindner, D. K., T. P. Celano et E. N. Ide. « Vibration Suppression Using a Proofmass Actuator Operating in Stroke/Force Saturation ». Journal of Vibration and Acoustics 113, no 4 (1 octobre 1991) : 423–33. http://dx.doi.org/10.1115/1.2930203.
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We consider proofmass actuators for vibration suppression in flexible structures. Proofmass actuators appear to have a significant force-to-weight ratio over other types of actuators; hence, there has been considerable interest in them recently. These actuators, however, have a maximum force capability imposed in part by the stroke length of the proofmass. This nonlinearity is difficult to handle because this constraint cannot be violated (unlike saturation of electronic devices). Furthermore, this constraint is peculiar to this type of actuator. In this paper we consider the control loop structure of a feedback control system which contains a proofmass actuator for vibration suppression. This loop structure is decomposed into inner control loops directly related to the actuator and outer loops which add damping to the structure. The inner loops determine the frequency response of the actuator. Evidently, when the frequency response of the actuator is matched to the stroke/force saturation curve, the actuator is most effective in the vibration suppression loops. Since the stroke/force saturation curve is characterized by the stroke length, mass of the proofmass, and the maximum current delivered by motor electronics, this actuator can be easily sized for a particular application. We also discuss the interaction between the inner loops around the actuator and the structure (with the vibration loops open). To illustrate our results, we consider linear DC motors as proofmass actuators for the COFS-I Mast. To discuss the interaction the actuator and the structure, we develop a simple result based on classical control theory. This result is of independent interest since it leads to a simple procedure for designing low order compensators for single-input-single-output systems with poles near the imaginary axis.
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Yarali, Ebrahim, Reza Noroozi, Armin Yousefi, Mahdi Bodaghi et Mostafa Baghani. « Multi-Trigger Thermo-Electro-Mechanical Soft Actuators under Large Deformations ». Polymers 12, no 2 (23 février 2020) : 489. http://dx.doi.org/10.3390/polym12020489.
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Dielectric actuators (DEAs), because of their exceptional properties, are well-suited for soft actuators (or robotics) applications. This article studies a multi-stimuli thermo-dielectric-based soft actuator under large bending conditions. In order to determine the stress components and induced moment (or stretches), a nominal Helmholtz free energy density function with two types of hyperelastic models are employed. Non-linear electro-elasticity theory is adopted to derive the governing equations of the actuator. Total deformation gradient tensor is multiplicatively decomposed into electro-mechanical and thermal parts. The problem is solved using the second-order Runge-Kutta method. Then, the numerical results under thermo-mechanical loadings are validated against the finite element method (FEM) outcomes by developing a user-defined subroutine, UHYPER in a commercial FEM software. The effect of electric field and thermal stimulus are investigated on the mean radius of curvature and stresses distribution of the actuator. Results reveal that in the presence of electric field, the required moment to actuate the actuator is smaller. Finally, due to simplicity and accuracy of the present boundary problem, the proposed thermally-electrically actuator is expected to be used in future studies and 4D printing of artificial thermo-dielectric-based beam muscles.
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Et. al., Dr B. Suresh Kumar,. « Modeling and Simulation of Feedback based Linear Electromechanical actuator ». Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no 2 (10 avril 2021) : 970–76. http://dx.doi.org/10.17762/turcomat.v12i2.1109.
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An actuator is a device that which provides control over certain automation systems and also provides tuning in movement or positioning in various applications like manufacture of valves, motor, wastewater treatment plants, onboard electronics based on the type of configuration of type of actuators. Out of the available types of actuators, linear Electro Mechanical Actuators (EMA) is a powerful and advanced tool which provides optimal solution for the field of automation, various applications where high speed, high precision with control are required. This paper proposes to have velocity feedback system to entire function of EMA’s in order to improve its functionality, and thus enhances the efficiency. This paper also proposes modeling and simulation of normal conventional linear Electro Mechanical Actuator and velocity feedback controlled EMA and compares the results in MATLAB/SIMULINK.
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Li, Bing, Shaohua Niu, Bingyang Li, Pengfei Wang et Yuli Qiao. « Design and Analysis of Mechanical Characteristics of EAP Flexible Drivers ». Machines 10, no 12 (19 décembre 2022) : 1241. http://dx.doi.org/10.3390/machines10121241.
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Electroactive polymer(EAP) is a “smart material” with high energy density, high electromechanical energy conversion efficiency, simple structure, good adaptability to the working environment, etc. It can be made into various shapes to realize flexible drivers. At present, the common EAP actuator is mainly composed of EAP film wound on a spring, and the output performance of this type of actuator is related to the spring stiffness, film prestretching rate, voltage, and other factors. Its working process is actually an electromechanical coupling process. In this paper, two types of cylindrical actuators are designed and tested. The electromechanical coupling mathematical model is constructed to simulate the driver. According to the experimental and simulation results, the relationship between the output displacement and elongation strain of EAP actuator and voltage, spring stiffness, and tensile rate is analyzed. It provides a reference and basis for the design of similar actuators.
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Cao, Hai Long, Zheng Tao Yan et Jing Jun Lou. « Magnetic Circuit Optimization Design and Simulation Analysis of Electromagnetic Inertial Actuator ». Advanced Materials Research 940 (juin 2014) : 356–61. http://dx.doi.org/10.4028/www.scientific.net/amr.940.356.
Texte intégralRésumé :
This paper introduces basic working principle of electromagnetic inertial actuators and establishes the mechanical model of actuator. With the method of three-level series permanent magnet, the actuator structure design was completed. According to the structure of the actuator, the magnetic circuit model of actuator was determined, and the design of magnetic circuit was completed. Through the comparison and analysis, the type of both ends of the cage was determined. The simulation analysis of actuators’ magnetic field was studied by using ANSYS, and then the parameters were optimized. The parameters of the optimal solution are concluded, and a way to the actuator parameters is found. This provides a theoretical basis for the production, development of the actuator, and provides a train of thought for the design of the new type of actuators in active vibration control.
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Wang, Chin-Cheng, et Ching-Po Wen. « Aerodynamic drag reduction for a truck model using DBD plasma actuators ». Advances in Mechanical Engineering 14, no 3 (mars 2022) : 168781322210878. http://dx.doi.org/10.1177/16878132221087852.
Texte intégralRésumé :
In this study, the effect of DBD plasma actuator based active flow control for a truck model was investigated. Two different electrode shapes which are linear and comb-shaped plasma actuators, are considered. The two DBD plasma actuators are placed at the leading edge or the trailing edge of the trailer, respectively. First, the drag reduction for the DBD plasma actuators at input voltages varying from 6 to 14 kVpp are compared. At a Reynolds number of 25,000, the maximum drag reduction using three comb-shaped plasma actuators at the trailing edge of the trailer is 8.7%, while the maximum drag reduction of three linear plasma actuators is approximately 6%. Then flow visualization behind the truck is performed. At a Reynolds number of 3500 and an input voltage of 14 kVpp, the results show that three comb-shaped plasma actuators installed at the trailing edge of the trailer produce a significant reduction in the wake region. In addition, the PIV measurement is used to quantize the flow field. It is observed that comb-shaped plasma actuators change the slope of the wake region more significantly than using linear plasma actuators. Therefore, this study shows that the use of DBD plasma actuators qualitatively and quantitatively reduces aerodynamic drag.
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Ozaki, Takashi, et Kanae Hamaguchi. « Electro-Aero-Mechanical Model of Piezoelectric Direct-Driven Flapping-Wing Actuator ». Applied Sciences 8, no 9 (19 septembre 2018) : 1699. http://dx.doi.org/10.3390/app8091699.
Texte intégralRésumé :
We present an analytical model of a flapping-wing actuator, including its electrical, aerodynamic, and mechanical systems, for estimating the lift force from the input electrical power. The actuator is modeled as a two-degree-of-freedom kinematic system with semi-empirical quasi-steady aerodynamic forces and the electromechanical effect of piezoelectricity. We fabricated actuators of two different scales with wing lengths of 17.0 and 32.4 mm and measured their performances in terms of the stroke/pitching angle, average lift force, and average consumed power. The experimental results were in good agreement with the analytical calculation for both types of actuators; the errors in the evaluated characteristics were less than 30%. The results indicated that the analytical model well simulates the actual prototypes.
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Matsuoka, Hiroki, Takefumi Kanda, Shuichi Wakimoto, Koichi Suzumori et Pierre Lambert. « Development of a Rubber Soft Actuator Driven with Gas/Liquid Phase Change ». International Journal of Automation Technology 10, no 4 (5 juillet 2016) : 517–24. http://dx.doi.org/10.20965/ijat.2016.p0517.
Texte intégralRésumé :
Soft rubber actuators are very useful in applications involving humans, such as in medicine and reflexology. Additionally, they are useful in industrial devices because of their softness. However, many soft rubber actuators are driven by pneumatic power, and the power source is usually bulky. This makes the application of soft rubber actuators difficult. In this study, we propose a novel small power source for soft rubber actuators, which uses the gas/liquid phase change phenomenon of the actuator working fluid. When fluids change their phase between liquid and vapor, a large volume change occurs. We assume that this volume change is sufficient to drive a single soft rubber actuator. We fabricated a prototype of an actuator comprised entirely of silicone rubber via a molding process. Using the first prototype, we confirmed that the actuator can be driven by the gas/liquid phase change of the actuator fluid. Then, we fabricated a second prototype that includes a cartridge heater inside its body. We applied an electronics coolant fluid to this actuator. From the results of several experiments, we confirmed that the actuator produced a maximum output force of 405 mN. When the actuator was driven by the gas/liquid phase change, its trajectory was almost the same as that when driven by air pressure. Hence, the proposed pressure source maintained the characteristics and advantages of the soft rubber actuator. We believe that a pressure source using the gas/liquid phase change phenomenon of a working fluid will mitigate the problems of the driving system of soft rubber actuators.
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Furutani, Katsushi, et Taizo Makino. « Influence of Matrix Circuit Switching Device Junction Capacitance on Piezoelectric Actuator Drive Performance ». International Journal of Automation Technology 3, no 3 (5 mai 2009) : 313–18. http://dx.doi.org/10.20965/ijat.2009.p0313.
Texte intégralRésumé :
Piezoelectric actuators are widely used as fine-motion actuators for positioning devices. Current pulse driving reduces displacement hysteresis, and the drive circuit provides current pulses considered constant charge pulses to the piezoelectric actuator. The circuit for devices with multiple degrees of freedom using multiple piezoelectric actuators should be simple. Matrix circuits are used to drive liquid crystal displays to reduce the number of drive-circuit control signals and components. A group of 2 × 2 piezoelectric actuators was driven alternately using a 4-switch matrix circuit, and two field effect transistors were used as a fast matrix circuit switch. Piezoelectric actuator drive performance was studied in the case of using the current pulse circuit and the matrix circuit. When the matrix circuit drove actuators performing as capacitive loads, switching device junction capacitors adversely affected drive performance.
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van der Linden, Franciscus LJ. « Modeling of geared positioning systems : An object-oriented gear contact model with validation ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 230, no 7-8 (29 juin 2015) : 1084–100. http://dx.doi.org/10.1177/0954406215592056.
Texte intégralRésumé :
In aerospace positioning actuators, gear efficiencies of 85% as well as breakout forces as high as 50% of the stall load of the actuator are observed at very low temperature conditions. Due to the low efficiency and high loading, stiction in these actuators is common which can lead to limit cycles or problems with controlling the actuators. To be able to correctly predict and assess these effects using simulations, a complete actuator, including motor, inverter, load, and controller is needed. This article presents an object-based, numerically efficient gear contact in a planar environment with user-defined friction and stiffness laws. The emphasis of the modeling is not a fully detailed contact model, but the description of a gear contact model which can be used for system simulations like complete aircraft electromechanical actuators including control surfaces. The presented model is suitable for complex gearing configurations (e.g. compound planetary gears). This is enabled by breaking down the transmission into the basic gear contacts. By adding masses and constraints from an existing component library, a complete transmission can be modeled. The generated model can be used for standalone simulations or can be used in multi-domain simulations like actuator modeling, in order to analyze the complete actuator model including parts such as drives, controllers and mechanical systems. The presented models have been validated using a gear test rig for a single stage spur gear.
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El-Agroudy, Mohammed N., Mohammed I. Awad et Shady A. Maged. « Soft Finger Modelling and Co-Simulation Control towards Assistive Exoskeleton Hand Glove ». Micromachines 12, no 2 (11 février 2021) : 181. http://dx.doi.org/10.3390/mi12020181.
Texte intégralRésumé :
The soft pneumatic actuators of an assistive exoskeleton hand glove are here designed. The design of the actuators focuses on allowing the actuator to perform the required bending and to restrict elongation or twisting of the actuator. The actuator is then modeled using ABAQUS/CAE, a finite element modeling software, and the open loop response of the model is obtained. The parameters of the actuator are then optimized to reach the optimal parameters corresponding to the best performance. Design of experiment (DOE) techniques are then approached to study the robustness of the system. Software-in-the-loop (SiL) is then approached to control the model variables via a proportional-integral-derivative (PID) control generated by FORTRAN code. The link between the two programs is to be achieved by the user subroutine that is written, where the subroutine receives values from ABAQUS/CAE, performs calculations, and passes values back to the software. The controller’s parameters are tuned and then the closed loop response of the model is obtained by setting the desired bending angle and running the model. Furthermore, a concentrated force at the tip of the actuator is added to observe the actuator’s response to external disturbance.
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Šolek, Peter, et Marek Maták. « An Active Control of the Thin-Walled Mechanical Systems ». Applied Mechanics and Materials 611 (août 2014) : 22–31. http://dx.doi.org/10.4028/www.scientific.net/amm.611.22.
Texte intégralRésumé :
This article deals with the influence of optimal actuator and sensor placement on the active control of thin-walled mechanical systems. The approach used for optimal actuator and sensor placement is based on the evaluation norms and. The optimal actuator and sensor placement satisfied the requirements on the controllability, observability and spillover prevention. The investigation of the optimal placement of actuators and sensors is demonstrated on the active vibration of the thin-walled two dimensional mechanical systems.
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Chaudhry, Z., et C. A. Rogers. « Enhanced Structural Control with Discretely Attached Induced Strain Actuators ». Journal of Mechanical Design 115, no 4 (1 décembre 1993) : 718–22. http://dx.doi.org/10.1115/1.2919260.
Texte intégralRésumé :
A new configuration where induced strain actuators such as piezoelectric ceramic patches or shape memory alloys are attached to a structure at discrete points (as opposed to being bonded) is presented. This paper specifically addresses discretely attached induced strain actuators like piezoceramic and electrostrictive actuators which are available in the form of plates or patches, and includes actuator flexural stiffness considerations. When activated, such actuators deform along with the structure (like bonded actuators), but in this case the actuator and the structure are free to deform independently. In such a scenario, the in-plane force of the actuator results in an additional moment on the structure and enhanced structural control. Also because now the actuator can be offset from the structure without an increase in the basic flexural stiffness of the structure, the actuator offset distance can be optimized to maximize actuator authority. Enhanced control is demonstrated by comparing the static response of a discretely attached actuator/beam system with its bonded counterpart system. Through a proper choice of the offset distance, the flexural control authority measured in terms of the moment applied to the substrate structure can be increased considerably for stiff and thick substrates. The advantage of this configuration over the bonded configuration is also verified experimentally. The limitations and considerations for the implementation of the concept in realistic structures are also discussed.
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Chen, Tiegang, Yan Ke, Shengbin Qiu, Jun Jiang, Qiang Zhang et 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 (1 février 2023) : 025009. http://dx.doi.org/10.1063/5.0127942.
Texte intégralRésumé :
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.
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Sun, Jin, Daozhou Zhang, Yang Zhang, Xinglong Zhu, Juntong Xi et Yu-Dong Zhang. « Research on performance of rigid-hoop-reinforced multi-DOF soft actuator ». Advances in Mechanical Engineering 13, no 6 (juin 2021) : 168781402110267. http://dx.doi.org/10.1177/16878140211026718.
Texte intégralRésumé :
In order to improve the bearing capacity of soft actuators, this article presents the development of the rigid-hoop-reinforced (spring or steel hoop) multi-DOF soft actuator. The actuator is composed of a rotary module with spring reinforcement on the silicone rubber-based body and a bending module with steel hoop reinforcement on the body. Compared with fiber-reinforced actuators, the bearing capacities of rigid-hoop-reinforced actuators made of 65Mn spring steel are improved. The radial and the axial bearing capacity for the bending module and the rotary module is raised by 29.6%, 28.2%, 30.6%, 49.6% respectively; under the same pressure, the spring-reinforced interval increases the maximum rotary angle of the rotary module, the steel hoop-reinforced interval increases the maximum bending angle of the bending module; with the same reinforcement type, the bending module with reinforcement interval of 10 mm has good bending characteristics that the bending angle changes with the pressure gently; the lower the hardness of silicone rubber base body, the better the adaptability and flexibility of the actuator, and the higher the hardness, the greater the bearing capacity of the actuator. Due to the above advantages, the rigid-hoop-reinforced multi-DOF soft actuator can be applied to medical devices which need high load-carrying capacity.
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Choi, S. B., et D. Y. Lee. « Rotational Motion Control of a Washing Machine Using Electrorheological Clutches and Brakes ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 219, no 7 (1 juillet 2005) : 627–37. http://dx.doi.org/10.1243/095440605x31472.
Texte intégralRésumé :
In this work, a rotational motion control of a washing machine featuring an electrorheological (ER) clutch/brake actuators is investigated. After analysing the field-dependent transmission and braking torques of the actuator on the basis of Bingham model, two sets of ER clutch/brake actuators are manufactured. The dynamic model of the actuators is then formulated by considering time constants. Subsequently, the actuators are applied to a small-sized pulsator type washing machine for rotational motion control. The control system model represented by spin-basket and pulsator motions is established and PID controllers are designed for two motions. The controllers are experimentally realized for washing and dehydrating motions under various loads. In addition, durability test for the washing motion control has been undertaken to demonstrate practical feasibility.
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Wu, Qianqian, Honghao Yue, Rongqiang Liu, Liang Ding et Zongquan Deng. « Parametric Design and Multiobjective Optimization of Maglev Actuators for Active Vibration Isolation System ». Advances in Mechanical Engineering 6 (1 janvier 2014) : 215358. http://dx.doi.org/10.1155/2014/215358.
Texte intégralRésumé :
The microvibration has a serious impact on science experiments on the space station and on image quality of high resolution satellites. As an important component of the active vibration isolation platform, the maglev actuator has a large stroke and exhibits excellent isolating performance benefiting from its noncontact characteristic. A maglev actuator with good linearity was designed in this paper. Fundamental features of the maglev actuator were obtained by finite element simulation. In order to minimize the coil weight and the heat dissipation of the maglev actuator, parametric design was carried out and multiobjective optimization based on the genetic algorithm was adopted. The optimized actuator has better mechanical properties than the initial one. Active vibration isolation platforms for different-scale payload were designed by changing the arrangement of the maglev actuators. The prototype to isolate vibration for small-scale payload was manufactured and the experiments for verifying the characteristics of the actuators were set up. The linearity of the actuator and the mechanical dynamic response of the vibration isolation platform were obtained. The experimental results highlight the effectiveness of the proposed design.
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Liu, B., et H. S. Tzou. « Distributed Photostrictive Actuation and Opto-Piezothermoelasticity Applied to Vibration Control of Plates ». Journal of Vibration and Acoustics 120, no 4 (1 octobre 1998) : 937–43. http://dx.doi.org/10.1115/1.2893923.
Texte intégralRésumé :
Conventional hard-wired sensor/actuator systems are likely sensitive to strong electromagnetic fields, cross-talks, electric noises, etc. Noncontact distributed opto-electromechanical actuators driven by high-energy lights do not require direct hardwire connections. These opto-electromechanical actuators can operate in hostile and extreme environments with strong magnetic and/or electric disturbances. In this study, detailed photostriction, pyroelectricity, thermoelasticity and photodeformation of 2-D opto-electromechanical photostrictive actuators are analyzed. A servo control system is proposed and its governing system equation is derived. The opto-electromechanical actuators are used in vibration control of a rectangular plate. Experimentally calibrated simulation results show that the opto-electromechanical actuators are effective in vibration control and the highest frequency of controllable vibration can achieve several hundred Hertz.
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Ventura, Erik, Cagri Oztan, Diego Palacios, Irene Isabel Vargas et Emrah Celik. « Magnetically-doped polydimethylsiloxane for artificial muscle applications ». Functional Materials Letters 13, no 01 (27 août 2019) : 1950089. http://dx.doi.org/10.1142/s1793604719500899.
Texte intégralRésumé :
Artificial muscle actuators demonstrate great potential for improving the quality of life. Recently, polymer muscle actuators have attracted attention due to their inexpensive and highly versatile methods of fabrication along with decent mechanical properties that can mimic those of natural muscles. The aim of this research is to investigate the usability of a magnetite-doped polymer powder, polydimethylsiloxane (PDMS), for artificial muscle actuators through an inexpensive method of production. PDMS samples doped with different levels of magnetite were fabricated using molds that were produced by additive manufacturing. Subsequently, the samples were magnetically and mechanically characterized by investigation of strength, elastic modulus, failure strain and permittivity, which are vital to meet the load capacity. The test results demonstrated that the mechanical and magnetic properties could be tailored as a function of doping level. Matching the mechanical response of these artificial components to those of artificial muscles will reduce the residual stresses, enhance the artificial muscle life and allow wider use of these materials for biomedical applications. This research rendered fabrication of molds possible for various applications where geometric customization of the actuator is required to meet endure severe loads, thanks to the freeform nature of additive manufacturing.
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Dauksher, Richard, Zachary Patterson et Carmel Majidi. « Characterization and Analysis of a Flexural Shape Memory Alloy Actuator ». Actuators 10, no 8 (22 août 2021) : 202. http://dx.doi.org/10.3390/act10080202.
Texte intégralRésumé :
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.
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Ferraresi, Carlo, Walter Franco et Giuseppe Quaglia. « A novel bi-directional deformable fluid actuator ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 228, no 15 (9 février 2014) : 2799–809. http://dx.doi.org/10.1177/0954406214522022.
Texte intégralRésumé :
The deformable fluid actuators available on the market, i.e. pneumatic muscles and pneumatic springs, are designed to mainly exert compressive or tensile forces. This paper deals with a novel fluid deformable actuator, with three membranes, called BiFAc3, whose particular feature is the ability to exert both tensile and compressive forces. The structure of the actuator is based on three cylindrical coaxial nonisotropic membranes connected to two end plates, whose original shape allows the independent supply of the three internal chambers. The first part of the paper deals with the internal structure and the geometry of the actuator, describes the operating principle and presents a prototype. The second part presents a modelling methodology that can be used to design and analyse the actuator in dynamic applications. The mathematical model of the actuator is based on three different levels of complexity which correspond to three consecutive design stages. The model has been experimentally validated: it is a useful tool for the choice of the actuator’s geometrical dimensions, in order to satisfy specific applicative requirements.
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Kaleta, Jerzy, Katarzyna Niemiec et Przemysław Wiewiórski. « Testing Mechanical and Electrical Defects in Piezoceramic Materials Resulting from Ultrasonic Vibrations ». Solid State Phenomena 240 (août 2015) : 11–16. http://dx.doi.org/10.4028/www.scientific.net/ssp.240.11.
Texte intégralRésumé :
The work presents recommendations related to the selection and installation of high power piezo ceramic rings dedicated to simultaneous power supply and data transmission for the purpose of extending life in their operation. Mechanical and electrical defects in piezoceramic elements of conical actuators were presented. The issue is important in the case when energy and information are transmitted at the same time using upper acoustic waves to autonomic wireless measurement nodes (WMN) in mechanical construction elements. A laboratory ultrasonic actuator was made and used to test ceramic rings. Additionally a dedicated vibration sensor was made and a measurement system for determination of frequency response of high power actuators was developed. Identification of the material used to make the ceramic rings and feeding electrodes was conducted. Next calibration tests of conical piezoelectric actuators were conducted and their defects were tested.
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Tzou, H. S., W. K. Chai et D. W. Wang. « Micro-Control Actions and Location Sensitivity of Actuator Patches Laminated on Toroidal Shells ». Journal of Vibration and Acoustics 126, no 2 (1 avril 2004) : 284–97. http://dx.doi.org/10.1115/1.1687398.
Texte intégralRésumé :
Toroidal shell structures have been proposed for components of inflatable telescopes and space structures, etc. over the years. Thus, distributed control of toroidal shells becomes a critical issue in precision maneuver, operation, and reliability. The converse effect of piezoelectric materials has made it one of the best candidates for distributed actuators. The resultant control forces and micro-control actions induced by the distributed actuators depend on applied voltages, geometrical (e.g., spatial segmentation and shape) and material (i.e., various actuator materials) properties of the actuators. The purpose of this analysis is to study the spatial location effects of actuator placement and to evaluate the micro-control actions imposed upon toroidal shell structures. Mathematical models and governing equations of the toroidal shells laminated with distributed actuator patches are presented first, followed by formulations of distributed control forces and micro-control actions including meridional/circumferential membrane and bending control components. Spatially distributed electromechanical microscopic actuation characteristics and control effects resulting from various meridional and circumferential actions of actuator patches at various shell locations are evaluated.
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Lan, Shaobin, et Zhibin Song. « Design of a New Nonlinear Stiffness Compliant Actuator and Its Error Compensation Method ». Journal of Robotics 2016 (2016) : 1–8. http://dx.doi.org/10.1155/2016/7326905.
Texte intégralRésumé :
Compliant actuators are more advantageous than stiff actuators in some circumstances, for example, unstructured environment robots and rehabilitation robots. Compliant actuators are more adaptive and safe. Constant stiffness compliant actuators have some limitations in impedance and bandwidth. Variable stiffness actuators improve their performance owing to introducing an extra motor to tune the stiffness of the actuators. However, they also have some limitations such as the bulky structure and heavy weight. It was also found that there are some waste functions existing in the current variable stiffness actuators and that the fully decoupled position control and stiffness tune are not necessary, because there exist some regular phenomena during most circumstances of human interaction with the robots which are “low load, low stiffness and high load, high stiffness”. In this paper, a design method for nonlinear stiffness compliant actuator was proposed which performed the predefined deflection-torque trajectory of the regular phenomenon. A roller and a cantilever which has special curve profile constitute the basic mechanical structure of the nonlinear stiffness compliant actuators. An error compensation method was also proposed to analyze the stiffness of elastic structure. The simulation results proved that the proposed method was effective in designing a predefined nonlinear stiffness compliant actuator.
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Pasquale, M. « Mechanical sensors and actuators ». Sensors and Actuators A : Physical 106, no 1-3 (septembre 2003) : 142–48. http://dx.doi.org/10.1016/s0924-4247(03)00153-5.
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Georges, Thomas, Vladimir Brailovski et Patrick Terriault. « Design of Active Bias Sma Actuators for Morphing Wing Applications ». Advanced Materials Research 409 (novembre 2011) : 627–32. http://dx.doi.org/10.4028/www.scientific.net/amr.409.627.
Texte intégralRésumé :
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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Basumatary, Kamal Kumar, Gaurav Kumar, Karuna Kalita et Sashindra K. Kakoty. « Stability analysis of rigid rotors supported by gas foil bearings coupled with electromagnetic actuators ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 234, no 2 (25 septembre 2019) : 427–43. http://dx.doi.org/10.1177/0954406219877903.
Texte intégralRésumé :
Rotors supported on gas foil bearings have low damping characteristics, which limits its application. A possible solution could be an integration of a gas foil bearing with an electromagnetic actuator. This paper discusses the effect of electromagnetic actuators on the stability of a rotor supported on gas foil bearings. A coupled dynamic model combining the dynamics of gas foil bearing and electromagnetic actuator has been developed. The fluid film forces from the gas foil bearings and the electromagnetic forces from the electromagnetic actuators are integrated into the equations of motion of the rotor. The sub-synchronous vibration present in case of conventional gas foil bearings is reduced and the stability band of the rotor is increased due to the implementation of electromagnetic actuator.
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Ma, Zhaoqi, et Dan Sameoto. « A Review of Electrically Driven Soft Actuators for Soft Robotics ». Micromachines 13, no 11 (1 novembre 2022) : 1881. http://dx.doi.org/10.3390/mi13111881.
Texte intégralRésumé :
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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Zheng, Kai, et Xing Hui Dong. « Experimental Analysis of Electro-Mechanical Characterization of Piezoelectric Stack Actuators ». Advanced Materials Research 129-131 (août 2010) : 28–32. http://dx.doi.org/10.4028/www.scientific.net/amr.129-131.28.
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This paper presents the results of experimental analysis and theoretical modeling of piezoelectric stack actuators. The focus of this paper is to understand the behavior of piezoelectric materials under the combined electro-mechanical loadings scenario, and to determine fundamental properties and optimum working conditions. Some parameters, including output displacement, hysteresis, output force and mechanical stiffness, are evaluated under varied pre-stress level and driven voltage values representative of in-service conditions. The measurements indicate strong dependence of the actuator piezoelectric properties and stiffness on the electro-mechanical loading conditions. This research also identified and calculated some parameters of the induced strain actuators electro-mechanical model, which are necessary to performing design optimization to achieve maximum energy transfer and minimum power consume.
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Boutchich, M., T. J. Mamtora, G. J. McShane, I. Haneef, D. F. Moore et J. A. Williams. « Force measurements on U-shaped electrothermal microactuators : Applications to packaging ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 222, no 1 (1 janvier 2008) : 87–96. http://dx.doi.org/10.1243/09544062jmes664.
Texte intégralRésumé :
The current paper critically reviews the prospects for the electrothermal actuation of elastic fixtures used as packaging elements for opto-electronic components. A convenient design methodology is presented together with a practical scheme for both prototyping out-of-plane bimorph actuators and measuring the vertical forces that they can deliver. A test bench has been assembled capable of measuring both the displacement and the restoring force delivered by such actuators which are patterned using laser micromachining of a bilayer consisting of 500 nm titanium tungsten (Ti-W) and 3 μm silicon nitride (SiN) thin films on a silicon substrate. An analytical model is derived to predict the dependence of the restoring force on the input electrical power and topology of the actuator. Experimental results are presented for bilayer actuators made of Ti-W/SiN in which attainable forces are of the order of 25 μN for input powers of 70 mW. An approximate theoretical model correlates well on the measured results of restoring force for different actuator geometries and supply currents. A packaging prototype was successfully tested using 550 μm long U-shape actuators with a gap width of 200 μm. These were able to move macroscopic components with rotations of up to 3°.