Mechanical Amplification Research Articles

Enhancing cross-Kerr coupling via mechanical parametric amplification.

We present a proposal to enhance the cross-Kerr coupling between the cavity and the mechanical oscillator significantly. Specifically, the periodic modulation of the mechanical spring constant induces strong mechanical parametric amplification, which leads to the cross-Kerr nonlinear enhancement. Also, we discuss its application in photon-phonon blockade and phonon-number measurement. We find that under the strong cross-Kerr coupling condition, not only the photon-phonon blockade effect is dramatically enhanced but also different phonon number is clearly distinguished. Our results offer an alternative approach to perform quantum manipulation between photon and phonon.

A physical model of mantis shrimp for exploring the dynamics of ultrafast systems

Efficient and effective generation of high-acceleration movement in biology requires a process to control energy flow and amplify mechanical power from power density-limited muscle. Until recently, this ability was exclusive to ultrafast, small organisms, and this process was largely ascribed to the high mechanical power density of small elastic recoil mechanisms. In several ultrafast organisms, linkages suddenly initiate rotation when they overcenter and reverse torque; this process mediates the release of stored elastic energy and enhances the mechanical power output of extremely fast, spring-actuated systems. Here we report the discovery of linkage dynamics and geometric latching that reveals how organisms and synthetic systems generate extremely high-acceleration, short-duration movements. Through synergistic analyses of mantis shrimp strikes, a synthetic mantis shrimp robot, and a dynamic mathematical model, we discover that linkages can exhibit distinct dynamic phases that control energy transfer from stored elastic energy to ultrafast movement. These design principles are embodied in a 1.5-g mantis shrimp scale mechanism capable of striking velocities over 26 m [Formula: see text] in air and 5 m [Formula: see text] in water. The physical, mathematical, and biological datasets establish latching mechanics with four temporal phases and identify a nondimensional performance metric to analyze potential energy transfer. These temporal phases enable control of an extreme cascade of mechanical power amplification. Linkage dynamics and temporal phase characteristics are easily adjusted through linkage design in robotic and mathematical systems and provide a framework to understand the function of linkages and latches in biological systems.

3-Bit Digital-to-Analog Converter with Mechanical Amplifier for Binary Encoded Large Displacements

We present the design, fabrication, and characterization of a MEMS-based 3-bit Digital-to-Analog Converter (DAC) that allows the generation of large displacements. The DAC consists of electrostatic bending-plate actuators that are connected to a mechanical amplifier (mechAMP), enabling the amplification of the DAC output displacement. Based on a parallel binary-encoded voltage signal, the output displacement of the system can be controlled in an arbitrary order. Considering the system design, we present a simplified analytic model, which was confirmed by FE simulation results. The fabricated systems showed a total stroke of approx. 149.5 ± 0.3 µm and a linear stepwise displacement of 3 bit correlated to 23 ≙ eight defined positions at a control voltage of 60 V. The minimum switching time between two input binary states is 0.1 ms. We present the experimental characterization of the system and the DAC and derive the influence of the mechAMP on the functionality of the DAC. Furthermore, the resonant behavior and the switching speed of the system are analyzed. By changing the electrode activation sequence, 27 defined positions are achieved upgrading the 3-bit systems into a 3-tri-state (33) system.

Power generation mechanism and performance analysis of parametrically excited piezoelectric composite devices for vibratory energy harvesting

Vibratory energy harvesting, that is, capturing the energy of environmental vibrations and transforming into electric forms, has flourished as an important research field for micro-power generation. As a means of mechanical amplification, a subtly designed parametrically excited energy harvester could produce more power output than a corresponding directly excited energy harvester. In this paper, a simple but effective composite structure for realizing parametrically excited piezoelectric energy harvesting is first introduced, and analyzed in details by combining the harmonic balance method and the energy balance equation. Direct numerical simulations are performed to validate the theoretical predictions. Special features describing two types of observable resonances are then revealed by comprehensively monitoring the frequency response of the mean-square voltage, the input power, the output power, the energy conversion efficiency, the phase angle and the phase difference. By comparing with the directly excited energy harvesters, the advantages of parametrically excited energy harvesters are finally revealed. The most important point view of this work is that the performance of vibratory energy harvesters stems from the input power. It is suggested that superior self-adjustable broadband vibration harvesting could be exploited by constructing optimal phase to maximize the input power to achieve supreme output power.

Механический усилитель звукового потока для диагностирования методами аускультации

The article notes that occupational safety in industry largely depends on the working equipment reliability. Among the various methods of maintaining equipment operability, there is a diagnostic method that helps to identify hidden defects before they appear. Thanks to equipment diagnostics, it is possible to increase safety, avoid accidents, catastrophes, and minimize repair and operation costs. There are two types of diagnostic methods: contact and non-contact. The most efficient non-contact methods are acoustic methods that are not associated with the destruction of the equipment under study. The possibility of applying the methods of auscultation used in medicine for diagnosing the state of industrial equipment is shown. Various methods and devices of auscultation are considered. The advantages and disadvantages of currently existing auscultation devices are noted. The design of an auscultation device with a mechanical sound flux seal is presented. Mechanical sealing of the sound flux is based on the parabolic reflectors use. The efficiency of using parabolic reflective surfaces is shown. A relationship is obtained that relates the magnitude of the amplification of the sound flux with the dimensions of the auscultation device. The results of calculations of the increase in the sound level in the auscultation device show that even with a sufficiently small ratio of the diameter of the inlet for the sound flux to the diameter of the outlet cross section of the sound flux and the diameter of the reduced parabolic reflector, a noticeable increase in the sound level is obtained when using a mechanical amplifier of the sound flux in the auscultation device.

B-AB24-02 PIEZOELECTRIC ENERGY HARVESTING FOR PACEMAKERS

Battery depletion is the leading cause of cardiac AICD pacemaker replacement. Auto-recharging via energy harvesting (EH) is a technique that could eliminate battery replacement. Piezoelectric EH converts mechanical energy into electrical energy. Research investigating EH for implantable medical devices is limited, and most approaches require additional surgery for attachment to the epicardium. To evaluate the use of piezoelectric coatings on transvenous leads and leadless pacemakers for EH without impacting the implantation procedure. In 15 in vivo porcine hearts we tested 5 piezoelectric materials and 7 device configurations. The devices were implanted into the RV and the effects of insertion location, heart rate, and RV contractility on the piezoelectric voltage output were investigated. The animals were paced at a heart rate of 80 to 140 bpm and iv dobutamine was used to increase heart contractility. Voltage outputs and power density were shown to increase with better performing piezoelectric materials and using device designs that amplified the mechanical inputs from heart contraction and relaxation. Estimate power density for the best performing device on a lead and leadless pacemaker was 10 μW/cm3 and 5 μW/cm3, respectively. We conclude that material selection and device design affect the EH capabilities of the coatings. Power densities of the devices are approaching that of typical pacemaker batteries of 25 μW/cm3. Future studies will investigate increasing outputs using a variety of approaches including multi-layer structures, mechanical amplification, and high-performance piezoelectric materials.

Direct Drive Servovalves Actuated by Amplified Piezo-Stacks: Assessment through a Detailed Numerical Analysis

This paper presents a feasibility study using commercially available amplified piezo-stacks for the direct actuation of four-way three-position (4/3) direct drive servovalves. The prospect of using amplified piezo-stacks in place of linear force motors is very attractive by virtue of their fast response speed and low weight. Piezo-stacks equipped with mechanical amplification systems can give levels of displacement suitable for this application. A very effective amplification system has recently been produced by some manufacturers and is based on a temperature-independent diamond structure. This paper details simulations of a 4/3 servovalve directly actuated by such a piezoelectric actuator with a diamond structure. To this end, well-established equations, implemented in Simulink by means of the libraries of Simscape Fluids, are used. The proposed architecture shows simplicity of construction; in addition, very good step response speed and frequency response are predicted by the simulations.

Propagation of Gaussian Schell-model beams in modulated graded-index media.

The evolution of partially coherent beams in longitudinally modulated graded-index media is studied. The special cases of Gaussian Schell-model beams and parametric modulation, when the modulation period is half the fiber self-imaging period, are examined in detail. We show that the widths of the intensity and coherence of Gaussian Schell-model beams undergo amplification in parametrically modulated parabolic graded-index media. The process is an analog of quantum mechanical parametric amplification and generation of squeezed states. Our work may find application in spatial and temporal imaging of partially coherent beams in fiber-based imaging systems.

An ultra-wide scanner for large-area high-speed atomic force microscopy with megapixel resolution

High-speed atomic force microscopy (HS-AFM) is a powerful tool for visualizing the dynamics of individual biomolecules. However, in single-molecule HS-AFM imaging applications, x,y-scanner ranges are typically restricted to a few hundred nanometers, preventing overview observation of larger molecular assemblies, such as 2-dimensional protein crystal growth or fibrillar aggregation. Previous advances in scanner design using mechanical amplification of the piezo-driven x,y-positioning system have extended the size of HS-AFM image frames to several tens of micrometer, but these large scanners may suffer from mechanical instabilities at high scan speeds and only record images with limited pixel numbers and comparatively low lateral resolutions (> 20–100 nm/pixel), complicating single-molecule analysis. Thus, AFM systems able to image large sample areas at high speeds and with nanometer resolution have still been missing. Here, we describe a HS-AFM sample-scanner system able to record large topographic images (≤ 36 × 36 µm2) containing up to 16 megapixels, providing molecular resolution throughout the image frame. Despite its large size, the flexure-based scanner features a high resonance frequency (> 2 kHz) and delivers stable operation even at high scans speeds of up to 7.2 mm/s, minimizing the time required for recording megapixel scans. We furthermore demonstrate that operating this high-speed scanner in time-lapse mode can simultaneously identify areas of spontaneous 2-dimensional Annexin A5 crystal growth, resolve the angular orientation of large crystalline domains, and even detect rare crystal lattice defects, all without changing scan frame size or resolution. Dynamic processes first identified from overview scans can then be further imaged at increased frame rates in reduced scan areas after switching to conventional HS-AFM scanning. The added ability to collect large-area, high-resolution images of complex samples within biological-relevant time frames extends the capabilities of HS-AFM from single-molecule imaging to the study of large dynamic molecular arrays. Moreover, large-area HS-AFM scanning can generate detailed structural data sets from a single scan, aiding the quantitative analysis of structurally heterogenous samples, including cellular surfaces.

High-Q Silicon Nitride Drum Resonators Strongly Coupled to Gates.

Silicon nitride (SiN) mechanical resonators with high quality mechanical properties are attractive for fundamental research and applications. However, it is challenging to maintain these mechanical properties while achieving strong coupling to an electrical circuit for efficient on-chip integration. Here, we present a SiN drum resonator covered with an aluminum thin film, enabling large capacitive coupling to a suspended top-gate. Implementing the full electrical measurement scheme, we demonstrate a high quality factor ∼104 (comparable to that of bare drums at room temperature) and present our ability to detect ∼10 mechanical modes at low temperature. The drum resonator is also coupled to a microwave cavity, so that we can perform optomechanical sideband pumping with a fairly good coupling strength G and demonstrate mechanical parametric amplification. This SiN drum resonator design provides efficient electrical integration and exhibits promising features for exploring mode coupling and signal processing.

Design and dynamic analysis of integrated architecture for vibration energy harvesting including piezoelectric frame and mechanical amplifier

Vibration energy harvesters (VEHs) can transform ambient vibration energy to electricity and have been widely investigated as promising self-powered devices for wireless sensor networks, wearable sensors, and applications of a micro-electro-mechanical system (MEMS). However, the ambient vibration is always too weak to hinder the high energy conversion efficiency. In this paper, the integrated frame composed of piezoelectric beams and mechanical amplifiers is proposed to improve the energy conversion efficiency of a VEH. First, the initial structures of a piezoelectric frame (PF) and an amplification frame (AF) are designed. The dynamic model is then established to analyze the influence of key structural parameters on the mechanical amplification factor. Finite element simulation is conducted to study the energy harvesting performance, where the stiffness characteristics and power output in the cases of series and parallel load resistance are discussed in detail. Furthermore, piezoelectric beams with variable cross-sections are introduced to optimize and improve the energy harvesting efficiency. Advantages of the PF with the AF are illustrated by comparison with conventional piezoelectric cantilever beams. The results show that the proposed integrated VEH has a good mechanical amplification capability and is more suitable for low-frequency vibration conditions.

Improvement on the manipulation of a single nitrogen-vacancy spin and microwave photon at single-quantum level

It remains a great challenge to realize direct manipulation of a nitrogen-vacancy (NV) spin at the single-quantum level with a microwave (MW) cavity. As an alternative, a hybrid system with the spin–phonon–photon triple interactions mediated by a squeezed cantilever-type harmonic resonator is proposed. According to the general mechanical parametric amplification of this in-between phonon mode, the direct spin–phonon and photon–phonon couplings are both exponentially enhanced, which can even further improve the coherent manipulation of a single NV spin and MW photon with a higher efficiency. In view of this triple system with enhanced couplings and the additional sideband adjustable designs, this scheme may provide a more efficient phonon-mediated platform to bridge or manipulate the MW quantum and a single electron spin coherently. It is also hoped to evoke wider applications in the areas of quantum state transfer and preparation, ultrasensitive detection and quantum nondestructive measurement, etc.

Membrane receptor-mediated mechano-transduction maintains cell integrity during pollen tube growth within the pistil.

Invasive or penetrative growth is critical for developmental and reproductive processes (e.g., pollen tube penetration of pistils) and disease progression (e.g., cancer metastasis and fungal hyphae invasion). The invading or penetrating cells experience drastic changes in mechanical pressure from the surroundings and must balance growth with cell integrity. Here, we show that Arabidopsis pollen tubes sense and/or respond to mechanical changes via a cell-surface receptor kinase Buddha's Paper Seal 1 (BUPS1) while emerging from compressing female tissues. BUPS1-defective pollen tubes fail to maintain cell integrity after emergence from these tissues. The mechano-transduction function of BUPS1 is established by using a microfluidic channel device mimicking the mechanical features of the invivo growth path. BUPS1-based mechano-transduction activates Rho-like GTPase from Plant 1 (ROP1) GTPase to promote exocytosis that facilitates secretion of BUPS1's ligands for mechanical signal amplification and cell wall rigidification in pollen tubes. These findings uncover a membrane receptor-based mechano-transduction system for cells to cope with the physical challenges during invasive or penetrative growth.

FBG Tactile Sensor for Surface Thickness and Shape Measurement

In recent years, numerous measurement techniques have been employed to characterize surface textures in the micrometer and nanometer range. Although these techniques have enabled significant advances in surface metrology, larger surface details are not easily measurable with such techniques. We propose a simple and reliable fiber Bragg grating (FBG) based tactile displacement sensor to measure a wide range of displacements that vary from $0.2~\mu \text{m}$ to 2mm. The device adopts a novel multi-pivot mechanical lever-based amplification mechanism to achieve a wide measurement range. Experimental results show that the sensor can measure both 219nm thick, thin-film coating and 1.22mm glass slide by selecting an appropriate pivot position. Further, the device is employed to identify topographies of three different surfaces of different dimensions. The sensor’s optimized configuration demonstrates an excellent displacement sensitivity of 63926pm/mm with a high resolution of 15.64nm. The repeatability of the sensor in this configuration is 2.44%.

Amplification of Cardiac Motor Functions by Prestin (Slc26a5)

The human heart is a durable biological motor, beating approximately 3.4 billion times in an 80-year lifespan. Actual cardiac performance originates in the function of cardiac myocytes, which are electromotile, changing in length in response to a change in membrane potentials. Groundbreaking work by Hugh Huxley and Jean Hanson et al. in the 1950s introduced the “sliding filament theory” that during muscle contraction, myosin and the filamentous actin protein form cross-bridges, allowing myosin to slide along actin, leading to length changes and force generation. Some muscle contraction mechanisms remain unexplained, such as how the sarcolemma accommodates ∼0.2-μm-displacement length changes per sarcomere per cardiac cycle without experiencing significant distortion. Here we invoke and test for the presence and function of a canonical non-conventional motor protein, prestin (Slc26a5), in cardiomyocytes as an amplifier of actin-myosin force generation. Prestin has been thought to be expressed exclusively in outer hair cells (OHCs) of the inner ear. It is a direct voltage-to-force convertor and mediates electromotility of OHCs as part of the molecular element of cochlear sound amplification. We hypothesize that prestin is expressed in mouse and human heart tissue and serves as the cardiac mechanical amplifier. We investigated whether the genetic deletion of Slc26a5 (Slc26a5-/-) produces in vivo and in vitro cardiac contractility changes. Multimodal Second Harmonic Generation (SHG) two-photon fluorescence microscopy and Stimulated Emission Depletion (STED) microscopy analyses were used to substantiate findings of the expression and functional roles of prestin in ventricular myocytes. We conclude that prestin serves to amplify actin-myosin force generation in cardiomyocytes, accounting for the non-linear properties of muscle contraction. The functional significance of prestin is underpinned by alterations of cardiac contractility in Slc26a5-/-mice. Our results suggest that prestin may serve as a broader cellular motor amplifier.

Design and closed-loop control of a piezoelectric actuator

Piezoelectric elements can produce a high displacement resolution with high force outputs but exhibits large hysteresis nonlinearities. An efficient way to compensate for nonlinearities is using a closed loop control technique. Another limitation for many applications is their relatively short displacement ranges. One method to avoid the above-mentioned shortcoming is to integrate a piezoelectric element with a mechanical displacement amplifier based on a compliant mechanism. This paper presents the design and closed-loop control of such a piezoelectric actuator. Using the integrated strain gauge sensors, a PI controller was designed and tested.

A theory of mechanobiological sensation: strain amplification/attenuation of coated liquid inclusion with surface tension

Cells are compressible and can be regarded as a kind of coated liquid inclusion embedded in a three-dimensional elastic matrix. In the presence of far-field loading, how the coating influences the mechanical response (e.g., volume change) of the liquid inclusion remains elusive, especially when surface tension effects become significant at cell size level. We developed a theoretical model to characterize the mechanical amplification or attenuation role of coating on spherical liquid inclusions, with surface tension and liquid compressibility accounted for. We found that surface tension could increase the volumetric strain of the inclusion through decreasing its effective bulk modulus. We further found that, when there is a monotonic stiffness variation (either decreasing or increasing) from matrix via coating to inclusion, the presence of coating amplified the volumetric strain compared with the case without coating; in the opposite, when there is a non-monotonic stiffness change from matrix via coating to inclusion, the volumetric strain is attenuated by the coating. The results are useful for understanding and exploring the mechanobiological sensation of certain types of cell, e.g., osteocytes and cancer cells.

Design of freeform geometries in a MEMS accelerometer with a mechanical motion preamplifier based on a genetic algorithm

This paper describes a novel, semiautomated design methodology based on a genetic algorithm (GA) using freeform geometries for microelectromechanical systems (MEMS) devices. The proposed method can design MEMS devices comprising freeform geometries and optimize such MEMS devices to provide high sensitivity, large bandwidth, and large fabrication tolerances. The proposed method does not require much computation time or memory. The use of freeform geometries allows more degrees of freedom in the design process, improving the diversity and performance of MEMS devices. A MEMS accelerometer comprising a mechanical motion amplifier is presented to demonstrate the effectiveness of the design approach. Experimental results show an improvement in the product of sensitivity and bandwidth by 100% and a sensitivity improvement by 141% compared to the case of a device designed with conventional orthogonal shapes. Furthermore, excellent immunities to fabrication tolerance and parameter mismatch are achieved.

Mechanically Amplified Milli-Newton Thrust Balance for Direct Thrust Measurements of Electric Thrusters for Space Propulsion

Direct thrust measurements by means of a thrust balance (TB) are the golden standard for measuring thrust and, concurrently, the specific impulse in electric thrusters. To measure these properties in the novel class of electrodeless plasma thrusters, a new TB based on the Variable Amplitude Hanging Pendulum with Extended Range (VAHPER) concept has been developed. The TB has a mechanical amplification mechanism with an angular magnification of $31^\circ /^\circ $ . Using Lagrangian mechanics, we show that the TB loaded with a 5.2-kg thruster prototype behaves like a damped harmonic oscillator with a natural frequency of 0.37 Hz. A variable damping system provides damping with an optimal damping ratio of 0.78, which corresponds to a settling time of only 1.8 s. Both the model and the damping and calibration system have been validated. To accommodate the particularities of medium power electrodeless plasma thrusters, the TB design includes the following features: an optical displacement sensor, water cooling, liquid metal connectors, and dedicated vacuum-rated electronics for autoleveling, remote (in-vacuum) calibration, and temperature monitoring. To test the TB, measurements were performed on a 500-W Helicon Plasma Thruster breadboard model. When loaded with this thruster, the measured stiffness of the system was 12.67 ± 0.01 mN/mm. For this stiffness, the thrust range is 150 mN with a 0.1-mN resolution. The relative uncertainty on the thrust measurements is found to be on the order of 2%.

Mechanical response of tensegrity dissipative devices incorporating shape memory alloys

To optimize the seismic performance prescribed by modern structural codes, buildings and infrastructures must provide adequate safety for design level earthquake excitations, with limited levels of damage. This paper deals with the computational modelling of a bracing system with tensegrity architecture, which operates as a lightweight mechanical amplifier of longitudinal displacements in the transverse direction, efficiently limiting the interstory drifts while dissipating energy. The proposed brace is based on a D-bar tensegrity structure with a rhomboidal shape comprising Shape-Memory Alloy (SMA) tendons. The SMA tendons can develop austenitic-martensitic (solid to solid) transformations, which enable them to amplify the signals into wide super elastic hysteresis, while subjected to mechanical cycles, comprising strains up to 6÷8%, with no residual deformations. The enhanced energy dissipation of the proposed SMA-D-bar (SMAD) braces are demonstrated through computational simulations of the response of braced frame to real earthquake events. The efficiency of the intended bracing to minimize the seismic impact of the served structure lays the foundation for the development of novel seismic energy dissipation systems integrating principles of tensegrity with superelasticity.