Showing papers on "Bimorph published in 2022"
TL;DR: In this paper, a tri-stable magneto-piezoelastic absorber (TMPA) is proposed for simultaneous energy harvesting and vibration isolation through a bimorph cantilever beam.
15 citations
TL;DR: In this article , a novel mechanically robust and multiresponsive Ti3C2Tx MXene-based actuator with high actuation performance via dual-mechanism synergistic effect driven by the hygroexpansion of bacterial cellulose (BC) layer and the thermal expansion of biaxially oriented polypropylene (BOPP) layer is developed.
Abstract: Multiresponsive and high-performance flexible actuators with a simple configuration, high mechanical strength, and low-power consumption are highly desirable for soft robotics. Here, a novel mechanically robust and multiresponsive Ti3C2Tx MXene-based actuator with high actuation performance via dual-mechanism synergistic effect driven by the hygroexpansion of bacterial cellulose (BC) layer and the thermal expansion of biaxially oriented polypropylene (BOPP) layer is developed. The actuator is flexible and shows an ultrahigh tensile strength of 195 MPa. Unlike the conventional bimorph-structured actuators based on a single-mechanism, the actuator developed provides a favorable architecture for dual-mechanism synergism, resulting in exceptionally reversible actuation performance under electricity and near-infrared (NIR) light stimuli. Typically, the developed actuator can produce the largest bending angle (∼400°) at the lowest voltage (≤4 V) compared with that reported previously for single mechanism soft actuators. Furthermore, the actuator also can be driven by a NIR light at a 2 m distance, displaying an excellent long-distance photoresponsive property. Finally, various intriguing applications are demonstrated to show the great potential of the actuator for soft robotics.
14 citations
01 Dec 2022
TL;DR: In this paper , the authors harnessed the snap-through instability of a bimorph thermal actuator to increase the bending speed of a soft robot with an actuation speed of 28.7 cm−1/s.
Abstract: Thermal actuation is a common actuation method for soft robots. However, a major limitation is the relatively slow actuation speed. Here we report significant increase in the actuation speed of a bimorph thermal actuator by harnessing the snap-through instability. The actuator is made of silver nanowire/polydimethylsiloxane composite. The snap-through instability is enabled by simply applying an offset displacement to part of the actuator structure. The effects of thermal conductivity of the composite, offset displacement, and actuation frequency on the actuator speed are investigated using both experiments and finite element analysis. The actuator yields a bending speed as high as 28.7 cm−1/s, 10 times that without the snap-through instability. A fast crawling robot with locomotion speed of 1.04 body length per second and a biomimetic Venus flytrap were demonstrated to illustrate the promising potential of the fast bimorph thermal actuators for soft robotic applications.
12 citations
TL;DR: In this article , analytical solutions of piezoelectric bimorph and unimorph actuator in cantilever configurations are developed using the second-order constitutive equation. But the results of these solutions are limited.
Abstract: Abstract In this article, analytical solutions of piezoelectric bimorph and unimorph actuator in cantilever configurations are developed using the second-order constitutive equation. Tip deflection ratio (TDR), a dimensionless parameter, is defined to analyze the effect of second-order coefficients of piezoelectric materials on the response of bimorph and unimorph actuators. Four piezoelectric unimorphs of varying geometries are fabricated and tested to verify the nonlinear response under applied electric field. Furthermore, second-order coefficients of lead zirconate titanate (PZT; APC 850) are derived by fitting the experimental data with nonlinear analytical solution. The nonlinear response of all the piezoelectric unimorphs compares well with the experimental results.
9 citations
TL;DR: In this article , a piezoelectric bimorph plate connected to a periodic arrangement of electric circuits is proposed, and both propagating and evanescent guided Lamb waves are investigated through the complex band structure resulting form using different shunting capacitor or inductor distributions.
8 citations
TL;DR: In this article , a wide-aperture adaptive optical system with the deformable mirror and Shack-Hartmann wavefront sensor was developed to correct the wavefront aberrations and improve the beam focusing in the petawatt Ti:Sa laser.
Abstract: The bimorph deformable mirror with a diameter of 320 mm, including 127 control electrodes, has been developed and tested. The flatness of the initial mirror surface of about 1 μm (P-V) was achieved by mechanically adjusting the mirror substrate fixed in the metal mount. To correct for the aberrations and improve the beam focusing in the petawatt Ti:Sa laser, the wide-aperture adaptive optical system with the deformable mirror and Shack–Hartmann wavefront sensor was developed. Correction of the wavefront aberrations in the 4.2 PW Ti:Sa laser using the adaptive system provided increases the intensity in the focusing plane to a value of 1.1 × 1023 W/cm2
8 citations
TL;DR: In this paper , electrothermal micromirrors based on different thermal actuators were reviewed, and also the mechanisms of those actuators are analyzed, including U-shape, chevron, thermo-pneumatic and thermal bimorph-based actuation.
Abstract: Electrothermal micromirrors have become an important type of micromirrors due to their large angular scanning range and large linear motion. Typically, electrothermal micromirrors do not have a torsional bar, so they can easily generate linear motion. In this paper, electrothermal micromirrors based on different thermal actuators are reviewed, and also the mechanisms of those actuators are analyzed, including U-shape, chevron, thermo-pneumatic, thermo-capillary and thermal bimorph-based actuation. Special attention is given to bimorph based-electrothermal micromirrors due to their versatility in tip-tilt-piston motion. The exemplified applications of each type of electrothermal micromirrors are also presented. Moreover, electrothermal micromirrors integrated with electromagnetic or electrostatic actuators are introduced.
6 citations
TL;DR: In this paper , the authors presented a MEMS speaker based on piezoelectric bimorph cantilevers that produces a higher sound pressure level (SPL), while keeping the size as small as possible.
6 citations
TL;DR: In this paper , a bio-inspired bimorph-structured millirobot with a transparent relaxor ferroelectric crystal was designed, which showed a maximum moving speed up to 9.22 b s−1 at 100 V, while the minimum driving voltage for initial movement can be as low as 3 V.
Abstract: Low driving voltage is important for miniaturization and untethered service of millirobots made of piezoelectric materials. In this research, we designed a bio-inspired bimorph-structured millirobot with a transparent relaxor ferroelectric crystal. Due to the ultrahigh piezoelectricity of the relaxor ferroelectric crystals and the optimized bimorph-based structure, the millirobot shows a maximum moving speed up to 9.22 b s−1 (body length per second) at 100 V, while the minimum driving voltage for initial movement can be as low as 3 V, which is more than two orders of magnitude smaller than that of millirobot based on dielectric elastomers. The maximum and minimum power consumptions of the millirobot are 71.6 mW and 85.9 μW, respectively. The robustness of the millirobot is reflected in its mechanical load stability carrying a 78 g mass (97.5 times of its weight) and its cryogenic tolerance. This work is believed to be beneficial to the design of various robust electromechanical devices with low driving voltage.
5 citations
TL;DR: In this article , a bimorph piezoelectric bending beam-based energy harvester was developed to scavenge energy from the human knee motion for powering body-worn electronics such as smartwatches and health monitors.
Abstract: Harvesting energy from the human body has attracted substantial attention from industries and academics as it is a promising solution to address the battery life issue. In this article, we developed a bimorph piezoelectric bending beam-based energy harvester to scavenge energy from the human knee motion for powering body-worn electronics such as smartwatches and health monitors. During walking, the human knee will flex and extend to periodically deform piezoelectric macro fiber composites (MFC) bounded to the bending beam, thus generating electricity. The mathematical models of the whole system including the model of the large deflection of the bending beam, movement analysis of the end of the bending beam (slider-crank mechanism), the model of piezoelectric transducers, and measurement of the human knee angle are developed to comprehensively study the harvester. To validate the presented mathematical models, experimental testing on a human body when the subject walks on a treadmill at three different walking speeds is conducted here. The experimental results show good agreement with the simulation results, which indicates that the developed models can characterize the harvester. In addition, the performance of the harvester walking in different contexts is also evaluated. The average power can reach 12.79 mW for level-ground walking, 9.91 mW for stair descending, and 7.70 mW for stair ascending, when walking at a self-selected speed.
5 citations
TL;DR: In this article , the exact solutions for the plate type piezoelectric bimorph energy harvesters composed of laminated cross-ply or angle-ply substrate plate were derived.
TL;DR: In this article, a theoretical model for a piezoelectric coupled torsional beam (PCTB) which can make full use of the positive effect of the PCTB material was developed.
TL;DR: In this paper , a cylinder harvester made of PCTBs is presented to improve the excitation frequency and a new theoretical model is developed to calculate the charge and voltage generated from the PCTB, which can make full use of the positive effect of the piezoelectric material.
TL;DR: In this paper , a large-aperture adaptive optical system with a bimorph deformable mirror and Shack-Hartmann wavefront sensor for aberration correction and beam focusing improvement in state-of-the-art petawatt Ti : sapphire lasers is presented.
Abstract: Abstract This paper reports a large-aperture adaptive optical system with a bimorph deformable mirror and Shack – Hartmann wavefront sensor for aberration correction and beam focusing improvement in state-of-the-art petawatt Ti : sapphire lasers. We consider methods for providing feedback to the wavefront sensor and obtaining an objective wavefront that optimises beam focusing onto a target. The use of an adaptive system with a controlled 127-channel 320-mm-aperture mirror in a Ti : sapphire laser with an output power of 4.2 PW has made it possible to obtain a record high laser beam intensity: 1.1 × 10 23 W cm −2 .
TL;DR: In this article , the authors presented an FPGA-based closed-loop adaptive optical system with a bimorph deformable mirror for correction of the phase perturbation caused by artificial turbulence.
Abstract: This paper presents a FPGA-based closed-loop adaptive optical system with a bimorph deformable mirror for correction of the phase perturbation caused by artificial turbulence. The system’s operating frequency of about 2000 Hz is, in many cases, sufficient to provide the real-time mode. The results of the correction of the wavefront of laser radiation distorted by the airflow formed in the laboratory conditions with the help of a fan heater are presented. For detailed consideration, the expansion of the wavefront by Zernike polynomials is used with further statistical analysis based on the discrete Fourier transform. The result of the work is an estimation of the correction efficiency of the wavefront distorted by the turbulent phase fluctuations. The ability of the bimorph adaptive mirror to correct for certain aberrations is also determined. As a result, it was concluded that the adaptive bimorph mirrors, together with a fast adaptive optical system based on FPGA, can be used to compensate wavefront distortions caused by atmospheric turbulence in the real-time mode.
TL;DR: In this article , the PLLA bimorph minimotor showed the maximum load of 1.2 g and the maximum torque of 0.019 cN·m, and the effective piezoelectric constants were 10.2 pC /N and 9.4 pC/N, respectively.
Abstract: Piezoelectric polymers have been widely used in a variety of applications, including tactile sensors, energy harvesting, polymer actuators, and biological devices. In this investigation, we fabricated the PLLA (poly(L-lactic Acid)-based bimorph structures for piezoelectric motor applications. First, a strain measurement setup was established to measure the strain of the PLLA and PDLA film at different temperatures. The effective piezoelectric constants d14 calculated for the PLLA and PDLA films were 10.2 pC/N and 9.4 pC/N, respectively. Furthermore, the PLLA films showed a strong thermostability of piezoelectricity at 130°C. The PLLA bimorph minimotor showed the maximum load of 1.2 g and the maximum torque of 0.019 cN·m. The minimotors were capable of rotating a plastic hemisphere container in the clockwise and counterclockwise directions at 65 V voltage. Due to the light weight, low driving voltage, and thermal stability, the PLLA/PDLA motors show a great promise in future Braille display, robots, and mini-digital camera applications.
TL;DR: In this article , an electronic stethoscope based on piezoelectric bimorph MEMS transducers for cardiac sound monitoring is presented, and the transducer is designed using a lumped element model, fabricated by MEMS process, packaged and assembled for final use.
Abstract: Cardiac auscultation is an orthodox method to prevent and diagnose cardiovascular diseases. Traditional stethoscopes cannot offer a highly reliable diagnosis, and electronic stethoscopes suffer from low signal-to-noise ratio (SNR) and high cost. This paper reports an electronic stethoscope based on piezoelectric bimorph MEMS transducers for cardiac sound monitoring. The stethoscope prototype, measuring 37 $\times 28\times12$ mm3, contains a preamplifier, holders and polydimethylsiloxane (PDMS) packaging. The transducer is designed using a lumped element model, fabricated by MEMS process, packaged, and assembled for final use. A triangular cantilever is chosen as a basic element for the transducer, with analytical analysis showing high sensitivity per unit area as a figure of merit (FoM). Performance parameters such as sensitivity and noise are experimentally characterized and consistent with simulation results. Owing to the outstanding receiving performance of the aluminum nitride (AlN) material and bimorph triangular cantilever structure of the transducer, compared with the commercial electronic stethoscopes, the proposed stethoscope demonstrates real-time phonocardiogram (PCG) with higher SNR. With its small size, high performance and low cost, the stethoscope is developed for portable and wearable cardiac sound monitoring. [2022-0007]
TL;DR: In this article , a detailed study of the dimensions of proof mass of the piezoelectric energy harvesters, based on geometry (length, height, and width), material, position and load resistance, had been carried out.
TL;DR: In this paper , the authors derived mathematical formulations for nonlinear dynamic analysis of axial stretch in convex tapered dielectric elastomer considering temperature dependent material properties, and determined the bending actuation of fish tail.
Abstract: Soft robots often show overwhelming performances. In the present work, mathematical formulations have been derived for nonlinear dynamic analysis of axial stretch in convex tapered dielectric elastomer considering temperature dependent material properties. The present formulation is based on the Gent model of hyperelasticity and the standard rheological model. The fish tail is modeled as bimorph dielectric elastomer actuator (DEA) for propulsion of soft fish robot. Based on the obtained axial stretch of the active layer, flapping movements of fish tail have been determined. The dependency of frequency, temperature, viscoelasticity, and taper effects on the dynamic performance in the active layer of bimorph DEA is studied. Investigation of time-dependent actuation, phase portraits, Poincare maps, bifurcation diagrams, and hysteresis loop associated in this system is carried out. The results reveal that at lower temperature more actuation is attained. At low frequency, time-dependent data show very small amplitude. With the increase in height taper, it is declared that the actuation increased. Thus, it is also observed that taper effects have significant role on the axial stretch. Subsequently, with the obtained stretch, deflection of bimorph DEA is determined through mathematical formulation in order to predict the bending actuation of fish tail.
TL;DR: In this article , an exact two-dimensional model that can be used for analyzing thin, moderately thick, and thick piezoelectric bimorph plate vibration harvesters is presented.
Abstract: Vibration energy harvesting using piezoelectric cantilevers has been widely studied during the past decade. As an alternative to piezoelectric cantilevers, plate-like energy harvesters can be much more effective in marine, aerospace, and automotive applications. This work presents an exact two-dimensional model that can be used for analyzing thin, moderately thick, and thick piezoelectric bimorph plate vibration harvesters. The model allows to consider for the substrate layer both homogenous materials, and those with varying properties along the thickness direction. For the latter case, porous materials with various porosity distributions are herein considered, and the piezoelectric layers are assumed to be wired in both parallel and series configurations. Rayleigh damping assumptions are also used to model the structural damping of the harvesting system. Using Hamilton’s principle and Gauss’s law, the energy harvesting model is established based on the first-order and the third-order shear deformation theories. Applying an analytical procedure to the electromechanical governing equations, closed-form steady-state response expressions, which relate the voltage output and the vibration response of the harvester to harmonic input force, are derived. Finally, the proposed model is validated, and the power generation performance of the plate harvester is discussed through conducting extensive parametric studies, covering the effect of design parameters, such as the applied electric load, porosity characteristics, electrical configuration, and geometrical parameters.
TL;DR: In this article , a unique strategy by harnessing the concept of feedback control between the piezoelectric bimorph subcells which are acting as sensor and actuator is conceptualized.
TL;DR: In this article , a novel piezoelectric energy harvester (z-PEH) is proposed to harness a significant amount of waste energy from human walking is proposed in the present work.
Abstract: Abstract A novel piezoelectric energy harvester (z-PEH) to harness a significant amount of waste energy from human walking is proposed in the present work. The unique feature of the z-PEH is that a greater number of piezoelectric discs are planted in the z -direction without consuming a wide area of the pavement or road surface, hence termed z-PEH. This enables minimum damage to the existing pavements or roads during installation, maintenance and repair works. The power generating piezoelectric bimorphs are glued to aluminum plates attached to the hollow steel structure which is mounted on a spring. The z-PEH module consists of eight commercially available bimorphs, with each bimorph having two circular piezoelectric discs of diameter 25 mm and a thickness of 0.25 mm. The experimental and numerical open-circuit voltages of a single PZT are 9.38, 15.86 and 29.5 V and 9.23, 18.31 and 28.6 V respectively for applied weights of 24.5, 49 and 73.5 N. The z-PEH module occupied an area of 21.1 × 18 cm 2 . The numerical design is further carried out in commercially available software ANSYS TM with the objective of enhancing output power of the z-PEH module with in the same area. It is found out that, the optimized z-PEH module with square bimorphs, generated an open-circuit Peak-to-peak voltage of 69.07 V and the maximum DC power generated is 0.56 mW for an applied force of 73.5 N. Also, the z-PEH module with 56 bimorphs resulted in an average DC power of 3.95 mW for a step loading of 490 N (equal to 50 kg) under maximum power transfer conditions. The power density in this case is 2.49 W m −3 .
TL;DR: In this article , shape memory alloy (SMA) based flexible mirrors were fabricated using the E-beam evaporation technique with varying pre-strain on the Kapton polyimide substrate during deposition.
Abstract: In this work, Shape Memory Alloy (SMA) based flexible mirrors were fabricated using the E-beam evaporation technique with varying pre-strain on the Kapton polyimide substrate during deposition. The mirrors are crucial for scanning and light beam deflection in MEMS applications. The fabricated bimorphs were investigated for actuation characteristics and reflectance as a mirror in the visible light range. The maximum displacement observed was 75 µm for 1% pre-strained bimorph. The study of shape recovery ratio revealed that bimorph without any pre-strain has the highest shape recovery of 1.637. For mirror application, the reflectance of the bimorph is of prime importance, which was determined by the UV-Visible study of fabricated samples. The maximum reflectance observed was 98.3% for both unstrained and 1% pre-strained samples. Energy Dispersive X-ray Spectroscopy (EDS) study displays the compositional variation of the deposited film.
TL;DR: In this paper , the authors proposed a bimorph sensor method capable of performing high scanning speed (0.5 m/s) in real-time pipeline inspection, which can detect and quantify the corrosion defects.
Abstract: Recently, bimorph sensors based on the in-line inspection (ILI) method have shown considerable promise for detecting surface defects (e.g., corrosions) in gas pipelines. However, the effect of physical parameters such as bimorph position and scanning speed on the performance of the bimorph sensor has not yet been investigated. As a result, the capability of the bimorph sensor for defect detection in pipelines is not clear. This study aims to optimize the physical parameters and investigate the influence of physical parameters on the performance of the bimorph sensor. For this purpose, first various corrosion defect sizes were considered and analyzed using piezoelectric theory. Next, an analytical relationship between the vibration response of the bimorph sensor and defect is derived using the Euler-Bernoulli beam theory. Finally, a real-time field test was conducted based on the installation of the proposed method on a developed smart PIG to demonstrate the detection efficiency of the bimorph sensor. The novel contributions of this study are as follows: (1) The proposed analytical method uses cantilever beam vibrational mode shapes together with the piezoelectric effect to detect and quantify the corrosion defects. (2) The current study proposed a bimorph sensor method capable of performing high scanning speed (0.5 m/s) in real-time pipeline inspection. (3) The performance of the proposed method on the various position of bimorph on the cantilever probe and scanning speed is studied analytically and experimentally. (4) Multiple corrosion defects and pipeline joints were detected and localized successfully in complex pipeline networks. • Proposed a bimorph sensor method to detect corrosion defects in gas pipelines. • Performance of the proposed method is investigated analytically and experimentally. • Bimorph sensor is designed and tested in a laboratory testbed. • Effectiveness of the proposed method on various physical parameters is presented. • Field test is conducted with the designed bimorph sensor array.
27 Jun 2022
TL;DR: In this article , a piezoelectric bimorph (PB) is fabricated to validate the nonlinear response of piezoceramic actuator in bending mode under high electric field.
Abstract: Linear constitutive equation of piezoelectricity is derived by neglecting the higher order terms in Tayler series expansion of Gibbs potential. At higher electric field, the contribution of higher order terms is significant and linear constitutive equation cannot be used to predict response of piezoelectric actuator. In this paper, a new technique of modification of material parameters (elastic coefficients and piezoelectric strain coefficient) in the linear constitutive equation of piezoelectricity, is proposed to simulate the nonlinear response of piezoceramic actuator. A piezoelectric bimorph (PB) is fabricated to validate the nonlinear response of piezoceramic actuator in bending mode under high electric field. Shear deformation beam theory is used to model the PB and superconvergent finite element with Hamilton principle is used to obtained the numerical solution of PB. Linear and nonlinear tip deflection of PB is compared with the experimental results. The deviation of measured tip deflection from the simulated linear response of PB has increased with the increase of the applied electric field. At 0.2 kV/mm the deviation is approximately 39\% from the linear response. A modification in material parameters is done to simulate the nonlinear response of PB. As a result, the nonlinear response of PB predicts the experimental results quite accurately.
TL;DR: In this paper , a real-time adaptive correction of optics, based on realtime metrology feedback, has benefitted numerous scientific communities for several decades, but it remains a major technological challenge to extend this concept into the hard x ray regime due to the necessity for active mirrors with single-digit nanometer height errors relative to a range of aspheric forms.
Abstract: High-speed adaptive correction of optics, based on real-time metrology feedback, has benefitted numerous scientific communities for several decades. However, it remains a major technological challenge to extend this concept into the hard x ray regime due to the necessity for active mirrors with single-digit nanometer height errors relative to a range of aspheric forms. We have developed a high-resolution, real-time, closed-loop “adaptive” optical system for synchrotron and x ray free electron laser (XFEL) applications. After calibration of the wavefront using x ray speckle scanning, the wavefront diagnostic was removed from the x ray beam path. Non-invasive control of the size and shape of the reflected x ray beam was then demonstrated by driving a piezoelectric deformable bimorph mirror at ∼ 1 H z . Continuous feedback was provided by a 20 kHz direct measurement of the optical surface with picometer sensitivity using an array of interferometric sensors. This enabled a non-specialist operator to reproduce a series of pre-defined x ray wavefronts, including focused or non-Gaussian profiles, such as flattop intensity or multiple split peaks with controllable separation and relative amplitude. Such changes can be applied in any order and in rapid succession without the need for invasive wavefront diagnostic sensors that block the x ray beam for scientific usage. These innovations have the potential to profoundly change how x ray focusing elements are utilized at synchrotron radiation and XFEL sources and provide unprecedented dynamic control of photon beams to aid scientific discoveries in a wide range of disciplines.
TL;DR: In this article , the authors analyzed the case of cantilever actuator modules with films of different compositions, deposited on the same substrate and highlighted how the composition of the alloy film with shape memory influences the modification of the curvature of bimorph cantilevers.
Abstract: Shape memory alloy film-based micro-actuators have their behaviour controlled by a change in the thermomechanical stress that occurs in the bimorph - shape memory alloy film plus substrate assembly. The modification of the composition of the shape memory alloy leads to a change of the transformation temperature and implicitly of the temperature at which the stress change takes place in the bimorph. The design of micro-actuator blocks in which the composition and/or the temperature control mode of each micro-actuator in the block allows to obtain successive or sequential transformation sequences. The paper analyses the case of cantilever actuator modules with films of different compositions, deposited on the same substrate. It is highlighted how the composition of the alloy film with shape memory influences the modification of the curvature of bimorph cantilever type actuators in the studied block.
TL;DR: In this paper , a cantilever construction design of an adaptive fiber-optics collimator (AFOC) based on piezoelectric bimorph actuators for tip/tilt control is introduced.
Abstract: A novel, to the best of our knowledge, cantilever construction design of an adaptive fiber-optics collimator (AFOC) based on piezoelectric bimorph actuators for tip/tilt control is introduced. With this new cantilever structure, an AFOC with a diameter of only 6 mm was developed, and the output laser beam deviation angle and resonance frequency of the device were measured. The experimental results show that this new AFOC can provide more than 1 mrad deflection angle at a 20 V driving voltage, and the first resonance frequency is about 500 Hz. Further, in order to verify whether the cantilever structure can be used in a high-power fiber collimator, a high-power X-Y positioner with an 8 mm diameter fiber end cap was developed. The experimental results show that the high-power X-Y positioner can output more than 2 kW laser power and provide about 330 µm displacement of the fiber end cap in the X direction and about 770 µm in the Y direction at a 150 V driving voltage.
TL;DR: In this paper , the output power map of a nonlinear energy harvester (PEH) made of a console beam and the membrane of a resonant vibration speaker is analyzed experimentally.
Abstract: In this paper, the output power map of a nonlinear energy harvester (PEH) made of a console beam and the membrane of a resonant vibration speaker is analyzed experimentally. The PEH uses two large piezoelectric patches (PZT-5H) bonded into a parallel bimorph configuration. The nonlinear response of the deformable structure provides a wider bandwidth in which power can be harvested, compensating for the mistuning effect of linear counterparts. The nonlinear response of the proposed PEH is analyzed from the perspective of its electrical performance. The proposed experimental method provides novelty by measuring the effects produced by the nonlinearity of the deformable structure on the output power map. The objective of this analysis is to optimize the size of the PZT patch in relation to the size of the console beam, providing experimental support for the design. The presentation of the most significant experimental results of a nonlinear PEH, followed by experimental mapping of the output power, ensured that the proposed objective was achieved. The accuracy of the experimental results was determined by the high degree of automation in the experimental setup, assisted by advanced data processing.
TL;DR: In this paper , a bimorph Piezoelectric Micromachined Ultrasonic Transducer (PMUT) fabricated with 8-inch standard CMOS-compatible processes is presented.
Abstract: This paper presents a novel bimorph Piezoelectric Micromachined Ultrasonic Transducer (PMUT) fabricated with 8-inch standard CMOS-compatible processes. The bimorph structure consists of two layers of 20% scandium-doped aluminum nitride (Sc0.2Al0.8N) thin films, which are sandwiched among three molybdenum (Mo) layers. All three Mo layers are segmented to form the outer ring and inner plate electrodes. Both top and bottom electrodes on the outer ring are electrically linked to the center inner plate electrodes. Likewise, the top and bottom center plate electrodes are electrically connected to the outer ring in the same fashion. This electrical configuration maximizes the effective area of the given PMUT design and improves efficiency during the electromechanical coupling process. In addition, the proposed bimorph structure further simplifies the device’s electrical layout with only two-terminal connections as reported in many conventional unimorph PMUTs. The mechanical and acoustic measurements are conducted to verify the device’s performance improvement. The dynamic mechanical displacement and acoustic output under a low driving voltage (1 Vpp) are more than twice that reported from conventional unimorph devices with a similar resonant frequency. Moreover, the pulse-echo experiments indicate an improved receiving voltage of 10 mV in comparison with the unimorph counterpart (4.8 mV). The validation of device advancement in the electromechanical coupling effect by using highly doped ScAlN thin film, the realization of the proposed bimorph PMUT on an 8-inch wafer paves the path to production of next generation, high-performance piezoelectric MEMS.