Topic
Bimorph
About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.
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TL;DR: In this paper, a bimorph microelectromechanical system (MEMS) generator for vibration energy harvesting is presented, which is in cantilever beam structure formed by laminating two lead zirconate titanate thick-film layers on both sides of a stainless steel substrate.
Abstract: This paper presents the development of a bimorph microelectromechanical system (MEMS) generator for vibration energy harvesting. The bimorph generator is in cantilever beam structure formed by laminating two lead zirconate titanate thick-film layers on both sides of a stainless steel substrate. Aiming to scavenge vibration energy efficiently from the environment and transform into useful electrical energy, the two piezoelectric layers on the device can be poled for serial and parallel connections to enhance the output voltage or output current respectively. In addition, a tungsten proof mass is bonded at the tip of the device to adjust the resonance frequency. The experimental result shows superior performance the generator. At the 0.5 g base excitation acceleration level, the devices pooled for serial connection and the device poled for parallel connection possess an open-circuit output voltage of 11.6 VP–P and 20.1 VP–P, respectively. The device poled for parallel connection reaches a maximum power output of 423 μW and an output voltage of 15.2 VP–P at an excitation frequency of 143.4 Hz and an externally applied based excitation acceleration of 1.5 g, whereas the device poled serial connection achieves a maximum power output of 413 μW and an output voltage of 33.0 VP–P at an excitation frequency of 140.8 Hz and an externally applied base excitation acceleration of 1.5 g. To demonstrate the feasibility of the MEMS generator for real applications, we finished the demonstration of a self-powered Bluetooth low energy wireless temperature sensor sending readings to a smartphone with only the power from the MEMS generator harvesting from vibration.
46 citations
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TL;DR: In this paper, a lumped parameter model of a vibration energy harvester consisting of a bimorph piezoelectric cantilever with end mass is presented, and the effect of load resistance on the resonant frequency and generated power is studied.
45 citations
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TL;DR: In this paper, a linear ultrasonic motors using a combination of the first longitudinal mode and the fourth bending mode were designed and fabricated, which were composed of a straight metal bar bonded with piezoelectric ceramic vibrators as a driving element.
Abstract: Linear ultrasonic motors using a combination of the first longitudinal mode and the fourth bending mode were designed and fabricated. The driving characteristics of the motors, which were composed of a straight metal bar bonded with piezoelectric ceramic vibrators as a driving element, were measured. Unimorph and bimorph ceramic vibrators were attached on three kinds of metal bars for constructing the stators of the linear motors. As results, motors made with the bimorph ceramic vibrators had higher velocity than motors of the unimorph vibrators. As a metal bar for stator, magnesium alloy, which has lower elastic coefficient than aluminum alloy, was better for the motors.
45 citations
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TL;DR: In this article, LiNbO3 was used as a bending actuator for precise position control in a single-domain lithium niobate plate at somewhat lower temperatures than the Curie temperature, which can serve as a piezoelectric actuator similar to the bimorph.
Abstract: Heat treatment of a bare single-domain lithium niobate plate at somewhat lower temperatures than the Curie temperature causes a local polarization reversal, thereby yielding a ferroelectric inversion layer. The plate with such an inversion layer can serve as a piezoelectric actuator similar to the bimorph, because the piezoelectric constants in the inversion layer are opposite in sign to the original ones. This paper reports the characteristics of the bending actuators using 140° rotated Y-cut LiNbO3. Experimental results show that the actuator characteristics have excellent linearity, no hysteresis, and little creep, and therefore they are suitable for precise position control.
45 citations
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TL;DR: In this paper, a technique for estimating the velocity of bending bimorph actuators, a popular choice for driving such micro-scale devices, that requires simple electronics and no additional mechanical components is presented.
Abstract: Sensor fabrication for microrobots is challenging due to their small size and low mass. As a potential solution, we present a technique for estimating the velocity of piezoelectric bending bimorph actuators, a popular choice for driving such microscale devices, that requires simple electronics and no additional mechanical components. Our approach relies on the insight that motion of the actuators causes varying strains on the surface on the piezoelectric material, which via the direct piezoelectric effect, results in a current proportional to the actuator velocity. We propose that the actuator be electrically approximated as a parallel combination of a frequency and voltage dependent resistor and capacitor, and a velocity proportional current source. We develop an experimental procedure to measure these quantities, and are able to experimentally determine the actuator tip velocity to within 10% accuracy over a range of voltages (25–200 V) and frequencies (1–2000 Hz, well beyond actuator resonance). We successfully apply this sensing methodology to two microrobots, the RoboBee and the Harvard Ambulatory MicroRobot (HAMR), to estimate the wing and limb motion respectively. We further use sensor feedback to close the loop on HAMR's leg phase and obtain desired leg trajectories near transmission resonance. The proposed sensor methodology is generic and can be applied to piezoelectric actuators of different geometries and configurations for uses in microrobotic applications.
45 citations