Piezo Driver Research Articles

Development, Optimization, Biological Assays, and In Situ Field Immersion of a Transparent Piezoelectric Vibrating System for Antifouling Applications

This paper presents the development and experimentations of transparent vibrating piezoelectric micromembranes dedicated to protecting immersed measurement instruments from marine biofouling. As any surface immersed is subject to the adhesion and settlement of organisms, especially in seawater, transparent materials quickly become opaque, resulting in deteriorated accuracy for optical sensors. According to this, we developed a transparent vibrating membrane to promote biofouling detachment in order to reduce the data quality drift and the frequency of maintenance operations on deployed optical sensors. In the first part, the design, the materials, and the steps to manufacture demonstrators are described. Then, the electromechanical characterizations of the demonstrators are carried out and interpreted with the support of FEM simulations. The last part describes the laboratory bioassays and the field immersion tests. Laboratory bioassays assess the antifouling potential of the vibrating piezoelectric membranes by exposing their surface to a suspended bacterial solution. In situ assays allow the membrane to perform in the Mediterranean Sea to assess their effectiveness in real conditions. Laboratory bioassays showed a great potential against the adhesion and settlement of a bacterial solution, while in situ tests confirmed the antifouling effect of piezoelectric vibrating micromembrane. Nevertheless, in situ experimentations revealed troubles with the piezo driver actuating the vibrating membranes, and tests should be carried out again with an improved piezo driver to reveal the full potential of the vibrating membranes. These are the first steps to set up an efficient antifouling vibrating system for immersed optical sensors.

Noncontact optical displacement measurements by dynamic contrast auto focusing for slow oscillatory motion

A noncontact displacement system suitable for tracking slow moving surfaces with low reflectivity is demonstrated. The displacement is measured by dynamic tracking of the moving focal plane of the sample under test. The system comprises a camera, a vertical digital piezo driver, and a data acquisition module. The tracking effect is achieved by continuously driving the sample with a 2-μm sweep around the focal plane, simultaneously acquiring the sample position and images of the part of the sample defined as a region of interest (ROI). The position of the focal plane is identified by fitting the contrast of the ROI versus the stage position to a Gaussian function. Using an ROI provides the ability to test various regions across the object and eliminates the demand for the surface to be flat or reflective. The system is low cost, is applicable to a large variety of samples and has an accuracy better than 10 nm.

High-Level Software Interface to the LLRF System Developed for the European Spallation Source Facility

The European Spallation Source (ESS) accelerator is composed of superconducting elliptical cavities. When the facility is running, the cavities are fed with an electric field from klystrons. Parameters of this field are monitored and controlled by the low-level radio frequency (LLRF) system. Its main goal is to keep the amplitude and phase at a given set point. The LLRF system is also responsible for the reference clock distribution. During operation, the cavities are periodically experiencing strain caused by the Lorentz force, while the high gradient of the electric field is generated for the beam acceleration. Even small changes in the physical dimensions of a cavity shift its resonance frequency. This phenomenon, called detuning, causes significant power losses. It is actively compensated by the LLRF control system, which can physically tune lengths of the accelerating cavities with stepper motors (slow, coarse-grained control) and piezo elements (active compensation during operation). This article describes the implementation and tests of the software supporting various aspects of the LLRF system and cavities management. The Piezo Driver management and monitoring tool is dedicated to a piezo controller device. The LO distribution application is responsible for configuration of the local oscillator. The cavity simulator tool was designed to provide access to properties of the hardware device, emulating behavior of the elliptical cavities. IPMI Manager Software was implemented to monitor the state of MicroTCA.4 crates, which are a major part of the LLRF system architecture. All applications have been created using the experimental physics and industrial control system (EPICS) framework and built in the ESS EPICS Environment (E3).

Erratum: "Simple, low-noise piezo driver with feed-forward for broad tuning of external cavity diode lasers" [Rev. Sci. Instrum. 89, 023102 (2018)

Erratum: "Simple, low-noise piezo driver with feed-forward for broad tuning of external cavity diode lasers" [Rev. Sci. Instrum. 89, 023102 (2018)

J3SPM: An Open-Source Microcontroller-Powered Control System for Atomic Force Microscope

In this paper, we propose a control system for an atomic force microscope (AFM) based on an open-source microcontroller. The system, named J3SPM, offers a low-cost and easy-to-use alternative to existing control systems. The hardware of J3SPM is composed of a data acquisition shield, which is compatible with the Arduino mega and due board and is equipped with a 24-bit resolution analog to digital converter, 16-bit resolution digital to analog converter, function generator, deflection sensor driver, and piezo driver. The control program is implemented using the Arduino integrated development environment. A graphic user interface is developed for the control system. To demonstrate the capability of the presented system, we employ J3SPM with a home-made AFM for imaging a sample with a step height of 21 nm in AC imaging mode.

Nested Miller Compensation Based Op-Amp Design for Piezoelectric Actuators

This study introduces the design of a practical three-stage operational amplifier (op-amp) using nested Miller compensation, particularly for piezoelectric actuators. Driving a piezoelectric actuator represents a challenge in amplifier design due to its large capacitive nature. A stable piezo driver needs to be free of oscillations and phase lag. Direct feedback compensation using a conventional Miller capacitor is an effective method as long as the capacitance of the load is considerably close to the value of the Miller capacitor. However, using a large capacitor causes a decrease in the slew rate and gain bandwidth. To avoid this, our design focused on the utilization of nested Miller compensation technique. A prototype of the design working at 100V peak to peak voltage (Vpp) is implemented using commercial off-the-shelf (COTS) components. The measurements show the successful driving capability and step-response of the op-amp design. In the design, Widlar current source is also utilized for thermal stability and short circuit protection. According to simulation results, the proposed op-amp has a slew rate of 0.5 V/μs, an open loop gain of 90dB with 3MHz Gain Bandwidth Product (GBP) and phase margin of 77°, and a common mode rejection ratio (CMRR) of 62dB.

Delivering Better Cockpit Design

A new piezo driver chip looks to advance realistic haptic feedback in automotive HMIs.

A piezo driver for piezoelectric bimorph actuators in micro-positioning application

Piezo driver for piezoelectric bimorph actuators is the key component for micro-positioning application. Hysteresis nonlinearity of piezoelectric bimorph actuators limits the performance of micro-positioning systems. A novel piezo driver was developed with Prandtl-Ishlinskii (P-I) model and correction network. The combination of P-I model and correction network can describe the rate-dependent hysteresis. Experiments were performed to validate the proposed piezo driver. The results show that the piezo driver can compensate the hysteresis of the piezoelectric bimorph actuator in the frequency range of 0.1 Hz to 10 Hz, and the accuracy of micro-positioning have been greatly improved.

A novel single butterfly stator piezo driver

In this paper, a new type of single butterfly piezo stick-slip linear actuator is proposed. The butterfly stator is driven by two symmetrical rectangular piezoelectric vibrators that are fixed at both ends to achieve a linear drive based on stick-slip motion. Based on the finite element method, the appropriate parameters of the rectangular piezoelectric vibrator with both ends fixed are obtained. Simulation analysis shows that the butterfly stator can increase the static friction force during the slow extension stage by driving the lateral movement of the foot, and reduce the dynamic friction force during the rapid contraction stage. A prototype was made and a series of experiments was conducted. Experimental results show that the maximum no-load motion velocity is about 3042 μm/s at a voltage of 100 V and a frequency of 1000 Hz; the maximum output force is 0.7 N at a voltage of 100 V and a locking force of 3.5 N; at a voltage of 60 V, At a frequency of 10 Hz and a locking force of 3.5 N, the minimum step displacement is about 0.77 μm.

High-Power Piezoelectric Tuner Driver for Lorentz Force Compensation

Superconducting Radio Frequency (SRF) cavities are used in modern accelerators to efficiently accelerate particles. When cavity is supplied with pulsed RF field it undergoes a mechanical strain due to the Lorentz force. The resulting deformation causes dynamic detuning whose amplitude depends on mechanical properties of the cavity, RF pulse rate and their profile. This effect causes considerable loss of acceleration performance. Therefore, it is usually actively compensated, most commonly with fast piezoelectric actuators. MicroTCA.4 standard was developed to accommodate control and data acquisition electronic systems of large-scale physics applications. The paper presents a design of high-power amplifier implemented using the MicroTCA.4 technology. The design of the driver was optimized for driving large-capacitance piezo actuators. Several possible architectures of the driver are presented and compared, taking into consideration the power and cooling limitations of MicroTCA.4. The design of a two-channel piezo driver and its initial laboratory test results are also discussed.

Development and characterization of liquid argon and methane microjets for high-rep-rate laser-plasma experiments.

A cryogenic microjet system has been used for delivering micron-scale continuous liquid hydrogen targets for laser-plasma experiments. This technique has been extended to higher-Z, higher boiling-point gases, including argon and methane. High-resolution shadowgraphy has been used to characterize the jet's morphology and pointing stability. A split and delay illumination source has also been developed for direct measurement of jet speeds without relying on assumptions of fluid flow conditions. Under typical conditions, the argon jets freeze solid due to evaporative cooling, but the methane jets remain liquid and break up to a droplet stream. A piezo driver is used to ensure the droplets are of uniform size. This jet has enabled the investigation of methane in planetary core conditions with high-rep-rate laser heating and x-ray laser probing.

Simple, low-noise piezo driver with feed-forward for broad tuning of external cavity diode lasers

We present an inexpensive, low-noise (<260 μVrms, 0.1 Hz-100 kHz) design for a piezo driver suitable for frequency tuning of external-cavity diode lasers. This simple driver improves upon many commercially available drivers by incorporating circuitry to produce a "feed-forward" signal appropriate for making simultaneous adjustments to the piezo voltage and laser current, enabling dramatic improvements in a mode-hop-free laser frequency tuning range. We present the theory behind our driver's operation, characterize its output noise, and demonstrate its use in absorption spectroscopy on the rubidium D1 line.

3D homogeneity study in PMMA layers using a Fourier domain OCT system

Micro-metallic particles embedded in polymers are now widely used in several industrial applications in order to modify the mechanical properties of the bulk. A uniform distribution of these particles inside the polymers is highly desired for instance, when a biological backscattering is simulated or a bio-framework is designed. A 3D Fourier domain optical coherence tomography system to detect the polymer's internal homogeneity is proposed. This optical system has a 2D camera sensor array that records a fringe pattern used to reconstruct with a single shot the tomographic image of the sample. The system gathers the full 3D tomographic and optical phase information during a controlled deformation by means of a motion linear stage. This stage avoids the use of expensive tilting stages, which in addition are commonly controlled by piezo drivers. As proof of principle, a series of different deformations were proposed to detect the uniform or non-uniform internal deposition of copper micro particles. The results are presented as images coming from the 3D tomographic micro reconstruction of the samples, and the 3D optical phase information that identifies the in-homogeneity regions within the Poly methyl methacrylate (PMMA) volume.

胎児の聴覚スクリーニング検査を目指した聴性誘発反応の計測

In order to examine hearing ability in fetuses, we have observed auditory evoked response induced by sound stimulation. The sound device consisted of a function generator, a piezo driver and a piezoelectric vibrator. The piezoelectric vibrator and two electrodes were positioned on the surface of the mother's abdomen above the head of fetus. Tone burst sound stimuli of 2 kHz, 70 dB were provided to the fetus through bone conduction. Measurement of brain waves of fetuses were performed in healthy pregnant women in the period of 33 to 38 weeks of gestation. Each subject was measured three times and potential curves were obtained. Then, correlation factors were calculated between the three potential curves to detect the brain waves by estimating the similarities of the curves. Simultaneously we evaluated a time variation of the correlation factors after stimulus. As a result, brain waves were detected 17 out of 19 subjects. The latencies of brain response to the sound stimuli in 35 - 36 weeks gestational age fetuses were longer than that in 37 weeks.

A Four-Channel, &lt;formula formulatype="inline"&gt;&lt;tex Notation="TeX"&gt;${\pm} $&lt;/tex&gt;&lt;/formula&gt;36 V, 780 kHz Piezo Driver Chip for Structural Health Monitoring

This paper describes a four-channel piezo driver chip for use in active structural health monitoring. Each channel can drive a piezoelectric transducer with a continuous-wave signal of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\pm} $</tex></formula> 36 V and 780 kHz. The waveform is synthesized using filtered pulse-width modulation (PWM), where the pulse transition times are precomputed through a least-square optimization problem. A calibration technique is introduced to achieve subnanosecond timing accuracy and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$-$</tex></formula> 40.5 dB signal distortion. A 13 mm <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{2}$</tex></formula> proof-of-concept IC was fabricated in a 0.25 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu$</tex> </formula> m BCD process and evaluated within an application test bed.

A hyperacute optical position sensor based on biomimetic retinal micro-scanning

Here we describe an active visual process whereby biomimetic micro-movements applied to an artificial retina improve the performances of a visual sensor in terms of both its detection sensitivity and its acuity. The elementary visual scanning sensor described here can detect a thin contrasting bar placed 2.5 m ahead, giving a minimum visibile (i.e., the smallest object width distinctly perceivable by the sensor) which is about 8-fold finer than the pixel angular pitch. In addition, the visual sensor is endowed with hyperacuity as it can locate a contrasting edge with a resolution which is 70-fold greater than its static resolution (i.e., the resolution without scanning). This high-resolution position sensing performance is based on encoding an angular position by an angular speed. The latter is then measured by a motion sensor inspired by those of the housefly. The retinal scanning process is generated by a piezo bender actuator driven at a frequency of 10 Hz by a tiny 1.5-g piezo driver. The small size, small mass and low power consumption of our visual scanning sensor make it well suited for a number of applications in fields ranging from mobile robotics to metrology and space technology, where the high-resolution contactless position sensing of naturally contrasting features is of prime importance.

Performance of the piezo-poppet valve. Part 1

The thermofluid mechanics of inflow (flow-to-close) and outflow (flow-to-open) conical poppet head valves is investigated for the range of small and controllable openings made available from the employment of a practical piezo-electric stack driver. A computational fluid dynamics (CFD) package suite is applied to the above task, the results from which are verified experimentally for several outflow slave valve (a valve with a non-electrical stand-in for the piezo stack) poppet lifts, cone angles, and pressure drops for the steady, non-isothermal flow of a test liquid (Tellus R37). Finally, the inflow valve performance is examined and a simple sizing technique consolidated. The results are compared, as far as is possible (quantitatively), with the findings of previous workers. This is done in order further to justify the use of CFD for the design of valves of small but potentially greater displacement than available from the contemporary piezo drivers and to underpin design exercises that are intended to optimize low lift valves for real operating conditions. In a companion paper unsteady/moving boundary and transient flow is tackled using a fast and precise piezo stack to actuate the same poppet head variations (as in the steady state case) as are the effects of manufacturing tolerances on poppet eccentricity, angular misalignment, and seat chamfering for small displacements.

Mechanical Fatigue Measurement via a Vibrating Cantilever Beam for Self-Supported Thin Solid Films

In this paper, we develop a novel experimental apparatus, referred to as the resonant frequency device, and establish methodology to measure the fatigue properties of thin solid films. Arranging thin-film strips of our specimens into the mechanical setting of a cantilever beam and using state-of-the-art piezo actuators to generate oscillation at the clamp of the cantilever, we create a system suitable for studying the material properties of the cantilever, such as Young's modulus, fatigue and possibly, loss tangent. Deformation of the cantilever is our controlled variable in the present study, and measured with fiber-optic probes pointed at the specimen and at the piezo driver. Stress is calculated from relative deformation of the cantilever specimen with respect to the piezo actuator via a photograph of the cantilever under vibration with a curve fitting method. A LabView computer program is developed for the fatigue tests to accurately count number of cycles applied on the specimens, and a feedback mechanism is adopted to maintain displacement during the tests. Here, we present our experimental setup, procedure and theoretical models for material-property extraction. For small displacement, the two-dimensional Euler–Bernoulli beam theory is adopted. With large displacement, the system behaves as the Duffing oscillator due to geometrical nonlinearity. In addition, some experimental observations of the piezo actuators and fiber optics are reported. The method is applied to evaluate the fatigue properties of nanolayered copper-niobium composites and significant increase in the fatigue endurance limit compared to the constituent materials in the bulk form is noted.

CURRENT CONTROLLED AMPLIFIER FOR PIEZO ACTUATOR AND ITS EXPERIMENTAL RESEARCH

Piezoelectric actuator controlled by electric field shows serious hysteresis and creep phenomena, which severely degrades the positioning accuracy. A piezoelectric ceramic driver based on current control is designed using the linear relationship between the displacement of the piezo actuator and the free charge on it. The displacement of the piezo actuator is controlled by controlling its velocity through controlling the current of the piezo actuator. Special circuits and pertinent control algorithm realize the combination of quickly driving and precising positioning. The experimental data show that piezo driver can perform linearly driving and quickly precising positioning of piezo actuator.

Roughness and hydrophobicity studies of nanofiltration membranes using different modes of AFM

Determination of the surface roughness by AFM is crucial to the study of particle fouling in nanofiltration. It is, however, very difficult to compare the different roughness values reported in the literature because of a lack in uniformity in the methods applied to determine surface roughness. AFM is used in both noncontact mode and tapping mode; moreover, the size of the scan area is highly variable. This study compares, for six different nanofiltration membranes (UTC-20, N30F, Desal 51HL, Desal 5DL, NTR7450, NF-PES-10), noncontact mode AFM with tapping mode AFM for several sizes of the scan area. Although the absolute roughness values are different for noncontact AFM and tapping mode AFM, no difference is found between the two modes of AFM in ranking the nanofiltration membranes with respect to their surface roughness. NTR 7450 and NF-PES-10 are the smoothest membranes, while the roughest surface can be found with Desal 51HL and Desal 5DL. UTC-20 and N30F are characterized by an intermediate roughness value. An increase in roughness with increasing scan area is observed for both AFM modes. Larger differences between the roughnesses of the membranes are obtained with tapping mode AFM because of the tapping of the tip on the surface. Phase imaging is an extension of tapping mode AFM, measuring the phase shift between the cantilever oscillation and the oscillation of the piezo driver. This phase shift reflects the interaction between the cantilever and the membrane surface. A comparison with contact angle measurements proves that a small phase shift corresponds to a large contact angle, representing a hydrophobic membrane surface.