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Opto-thermally Excited Fabry-Perot Resonance Frequency Behaviors of Clamped Circular Graphene Membrane
摘要： An opto-thermally excited optical fiber Fabry-Perot (F-P) resonant probe with suspended clamped circular graphene diaphragm is presented in this paper. Then, the dependence of resonance frequency behaviors of graphene diaphragm upon opto-mechanical factors including membrane properties, laser excitation parameters and film boundary conditions are investigated via COMSOL Multiphysics simulation. The results show that the radius and thickness of membrane will linearly affect the optical fiber light-induced temperature distribution, thus resulting in rapidly decreasing resonance frequency changes with the radius-to-thickness ratio. Moreover, the prestress can be regulated in the range of 108 Pa to 109 Pa by altering the environmental temperature with a scale factor of 14.2 MPa/K. It is important to note that the availability of F-P resonant probe with a defective clamped circular graphene membrane can be improved notably by fabricating the defected circular membrane to a double-end clamped beam, which gives a broader perspective to characterize the resonance performance of opto-thermally excited F-P resonators.
关键词： opto-thermal actuation,graphene membrane,Fabry-Perot resonator,resonance frequency simulation
更新于2025-11-28 14:23:57
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A Design Principle for Actuation of Nematic Glass Sheets
摘要： A continuum mechanical framework is developed for determining (a) the class of stress-free deformed shapes and corresponding director distributions on the undeformed configuration of a nematic glass membrane that has a prescribed spontaneous stretch field and (b) the class of undeformed configurations and corresponding director distributions on it resulting in a stress-free given deformed shape of a nematic glass sheet with a prescribed spontaneous stretch field. The proposed solution rests on an understanding of how the Lagrangian dyad of a deformation of a membrane maps into the Eulerian dyad in three dimensional ambient space. Interesting connections between these practical questions of design and the mathematical theory of isometric embeddings of manifolds, deformations between two prescribed Riemannian manifolds, and the slip-line theory of plasticity are pointed out.
关键词： Thin sheets,Nematic glass,Actuation,Design
更新于2025-09-23 15:22:29
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Investigation on Solar PV generation and design of switched reluctance motor for Smart Agriculture actuation system
摘要： This paper presents standalone solar photovoltaic (PV) powered fed actuation system employing a switched reluctance motor (SRM) particularly used in remote and rural areas. The converter efficiency is achieved by changing ON and OFF state of solar PV drive. An electronic commutation drives SRM drive with achieved by position hall sensor and encoder. The modified boost converter is proposed in single stage to conversion of PV fed power and inverter with reduced switching losses. Further proposed system is designed to reduce cost of system using simple design and control. This paper also proposes the speed control strategy of SRM motor with an artificial intelligent based Adaptive neuro fuzzy inference (ANFIS) system to achieve desired motor velocity as stated in reference velocity in farm lands. The system proposed is subjected to analysis the performance of drive and controller in both load and no-load conditions. Initially, a simulation model is modeled in MATLAB-SIMULINK with corresponding environments. The experimental setup for proposed system is developed using FPGA based SPEEDGOAT real time target machine. The simulation and hardware results suggest feasibility of proposed system in real time.
关键词： SRM drive,SPEED GOAT,MATLAB-SIMULINK,actuation,ANFIS,PV,Modified boost converter
更新于2025-09-23 15:22:29
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Controlling the shape of 3D microstructures by temperature and light
摘要： Stimuli-responsive microstructures are critical to create adaptable systems in soft robotics and biosciences. For such applications, the materials must be compatible with aqueous environments and enable the manufacturing of three-dimensional structures. Poly(N-isopropylacrylamide) (pNIPAM) is a well-established polymer, exhibiting a substantial response to changes in temperature close to its lower critical solution temperature. To create complex actuation patterns, materials that react differently with respect to a stimulus are required. Here, we introduce functional three-dimensional hetero-microstructures based on pNIPAM. By variation of the local exposure dose in three-dimensional laser lithography, we demonstrate that the material parameters can be altered on demand in a single resist formulation. We explore this concept for sophisticated three-dimensional architectures with large-amplitude and complex responses. The experimental results are consistent with numerical calculations, able to predict the actuation response. Furthermore, a spatially controlled response is achieved by inducing a local temperature increase by two-photon absorption of focused light.
关键词： light-induced actuation,pNIPAM,temperature response,stimuli-responsive materials,gray-tone lithography,hetero-microstructures,laser lithography,3D microstructures
更新于2025-09-23 15:22:29
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[Biologically-Inspired Systems] Stimuli-Responsive Dewetting/Wetting Smart Surfaces and Interfaces Volume 11 || Photo-Responsive Superwetting Surface
摘要： Photo-responsive surfaces, especially for the photo-responsive superwetting surface, have aroused great interests in smart control devices for a few years due to their remote control and selectivity. This chapter focuses on the photo-responsive wettability on the superwetting surface and their typical applications, particularly on switchable wettability on photo-responsive surfaces and their applications such as droplet actuation, adhesion control, liquid printing and oil-water separation. Finally, our personal point of the prospects and challenges of the photo-responsive wettability surfaces are presented.
关键词： Photo-responsive surface,Separation,Nanomaterials,Liquid actuation,Superwetting
更新于2025-09-23 15:21:21
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Stress-Controlled Frequency Tuning and Parametric Amplification of the Vibrations of Coupled Nanomembranes
摘要： Noninvasive tuning of the mechanical resonance frequencies of suspended parallel nanomembranes in various monolithic arrays is achieved by piezoelectric control of their tensile stress. Parametric amplification of their thermal fluctuations is shown to be enhanced by the piezoelectric actuation and amplification factors of up to 20 dB in the sub-parametric oscillation threshold regime are observed.
关键词： nanomembrane resonators,piezoelectrical actuation,parametric excitation,stress engineering
更新于2025-09-23 15:21:01
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Germanium photodetector with alleviated space-charge effect
摘要： A branch of robotics, variable impedance actuation, along with one of its subfields variable stiffness actuation (VSA), is gaining momentum recently. There have been many thorough studies earlier in the design and recently in the control of these systems. The performance of these systems is mainly limited by their physical constraints, such as actuator nominal torque and maximum elastic element stiffness. This paper discusses the integration of reaction wheels to VSA systems and using reactive torques to improve the performance of the combined system. Since the compliant nature of VSA mechanisms is often associated with cyclic motion, reactive torques can be used to amplify the robot motion and accumulate more energy in the elastic elements in a given period of time. After presenting our modeling and control framework for reaction wheel-integrated VSA robots, we benchmark the performance of a reaction wheel-integrated VSA system using an explosive ball throwing task. Specifically, extensive simulation and real-world experiments are conducted with three different configurations: VSA-only, reaction wheel-only, and reaction wheel-integrated VSA. The results of these experiments show the benefits of reaction wheel-integrated VSA robots compared with the two other configurations.
关键词： model predictive control,Variable impedance actuation,robot control,reaction wheels,manipulator dynamics
更新于2025-09-23 15:21:01
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Stability and vibrations control of a stepped beam using piezoelectric actuation
摘要： The objects of this studies are the stability and transversal vibrations of the system composed of three segments, where in the centre part of the system two piezoelectric patches are perfectly bonded to the top and bottom surface of the host beam. The system is kinematically loaded as a result of prescribed displacement of one or both end supports. For the analysis purposes three different beam end supports have been taken into consideration, which prevent longitudinal displacements i.e. clamped-clamped, clamped-pinned and pinned-pinned. This type of beam loading not only affect its natural vibration frequencies but also the system’s stability. By introducing the electric field to the piezo patches, depending on its vector direction, in-plane stretching or compressive residual force may be induced. Presented results show that piezo actuation can significantly modify both the critical buckling force and the vibration frequency.
关键词： vibrations,piezo actuation,stepped beam,stability
更新于2025-09-23 15:21:01
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[ASME ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - Quebec City, Quebec, Canada (Sunday 26 August 2018)] Volume 4: 23rd Design for Manufacturing and the Life Cycle Conference; 12th International Conference on Micro- and Nanosystems - Complex Logic Operations Based on MEMS Resonators
摘要： Complex logic functions based on micro electromechanical resonators has significant attention. Realization of complex logic functions through cascading micro resonators has been deterred by challenges involved in their interconnections and the large required array of resonators. This paper presents a micro electromechanical system MEMS resonator with multiple input (actuation) and output (detection) that enables the realization of complex logic operations. The devices are based on a compound resonator consisting of an in- plane clamped-guided arch beam that is mechanically coupled from its guided side to two flexure beams and to another T- shaped resonant beam. As examples, we experimentally demonstrate using the device to realize a half adder and a 1:2 DEMUX, based on electrothermal and electrostatic tuning of the arch beam and side resonant beam. The logic operation is frequency modulation. This paper demonstrates that with such compound MEMS resonators, it is possible to build more complex logic functionalities.
关键词： Multi-input and multi-output,half adder,DEMUX,electrostatic and electrothermal actuation,MEMS resonators
更新于2025-09-23 15:21:01
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A Fast Multiobjective Optimization Strategy for Single-Axis Electromagnetic MOEMS Micromirrors
摘要： Micro-opto-electro-mechanical (MOEMS) micromirrors are an enabling technology for mobile image projectors (pico-projectors). Low size and low power are the crucial pico-projector constraints. In this work, we present a fast method for the optimization of a silicon single-axis electromagnetic torsional micromirror. In this device, external permanent magnets provide the required magnetic field, and the actuation torque is generated on a rectangular multi-loop coil microfabricated on the mirror plate. Multiple constraints link the required current through the coil, its area occupancy, the operating frequency, mirror suspension length, and magnets size. With only rather general assumptions about the magnetic field distribution and mechanical behavior, we show that a fully analytical description of the mirror electromagnetic and mechanical behavior is possible, so that the optimization targets (the assembly size, comprising the mirror and magnets, and the actuation current) can be expressed as closed functions of the design parameters. Standard multiobjective optimization algorithms can then be used for extremely fast evaluation of the trade-offs among the various optimization targets and exploration of the Pareto frontier. The error caused by model assumptions are estimated by Finite Element Method (FEM) simulations to be below a few percent points from the exact solution.
关键词： MOEMS,micromirrors,magnetic actuation,pico-projectors,Micro-electro-mechanical systems (MEMS),multiobjective optimization
更新于2025-09-23 15:21:01