Design Of Piezoelectric Actuator Research Articles

Effect of variable amplitude superimposed wave on piezoelectric actuator performance and experimental performance analysis

In order to bridge the gap between the effects of superposition of unequal amplitude waves on superimposed waves, this paper investigates the effects of variable amplitude superimposed waves on piezoelectric actuators. The generation mechanism of traveling waves is explored from the principle of superposition of waves. A mathematical model of the piezoelectric beam is established based on the Euler-Bernoulli beam theory and the Lagrange equation. It is the first time that the effects of variable amplitude superimposed waves on motion performance are investigated from both theoretical and experimental perspectives. The effects of variable amplitude waves on kinematic performance are tested by changing different excitation frequencies, different positions and different loadings. The relationship between the amplitude ratio A and the motion performance is given. It is shown that there is an approximately linear negative correlation between the amplitude ratio and the motion performance when the amplitude ratio A = 1–2.4. This study provides a new idea for the generation of traveling waves and provides a reference for the design and application of piezoelectric actuators.

Design and experimental study of a planar piezoelectric actuator with resonant actuation

Planar piezoelectric actuators, which can achieve high-precision motions over a wide range, have been widely applied in high-end equipment fields. However, the existing planar piezoelectric actuators can no longer meet the high actuation characteristics required for the rapidly development of these fields, which include large travel, high resolution, fast speed, planar three degrees of freedom (3-DOF) and a compact structure. A planar piezoelectric actuator with resonant actuation is proposed and tested in this work. The actuator consists of four symmetrically configured uniform bending-bending hybrid piezoelectric units, which coordinate to achieve large travel and planar 3-DOF characteristics. A vibration isolation mechanism adopting thin beam structure with low stiffness in coupling directions is designed to achieve vibration isolation among the units. The actuator can operate in high frequency resonance mode and low frequency stepping mode, allowing for the achievement of high-speed and high-resolution characteristics. A prototype is fabricated and tested. A compact structure measuring 53 mm × 53 mm × 13 mm and weighing only 30.2 g has been achieved. The maximum linear and rotary speeds have been tested to be over 400 mm/s and 13 rad/s, respectively. The linear and rotary resolutions are 0.42 μm and 12.9 μrad, respectively. The proposed actuator achieves characteristics of large travel, high resolution, fast speed, 3-DOF and a compact structure.

Sensitivity of Piezoelectric Stack Actuators

This paper investigates the properties of a mass−attached piezoelectric stack actuator and analyzes its sensitivity, which is defined as the spectrum of the driving force (the output) caused by a single−frequency voltage (the input). The force spectrum is utilized because of the nonlinear hysteresis effect of the piezoelectric stack. The sensitivity analysis shows that the nonlinear dynamics of the actuator can be interpreted as a cascade of two subsystems: a nonlinear hysteresis subsystem and a linear mechanical subsystem. Analytical solutions of the nonlinear differential equations are proposed, which show that the nonlinear transformation can be described by a steady−state mapping of a single−frequency voltage input to a multiple−frequency driving force at the driving frequency and its odd harmonics. The steady−state sensitivity is then determined by the response of the mechanical subsystem to the line spectrum of the driving force. The maximum sensitivity can be achieved by setting the frequency of the input voltage close to the natural frequency of the mechanical subsystem. The analytical model is also validated by a numerical model and experimental results and it may be used for the analysis and design of piezoelectric actuators with different structural configurations.

Design and experimental investigation of a novel stick-slip piezoelectric actuator based on V-shaped driving mechanism

Design and experimental investigation of a novel stick-slip piezoelectric actuator based on V-shaped driving mechanism

Lightweight design of piezoelectric linear displacement accumulation actuator for airfoil deployment

The electromagnetic servo steering gear commonly used in the modern small guided aircraft has parasitic electromagnetic fields that affect the navigation and guidance accuracy, and its deceleration mechanism will increase the volume and mass, and the operating temperature range of the electromagnetic steering gear is small. A recently developed piezoelectric linear displacement accumulating high-power density actuator can solve those problems effectively. A virtual prototype model of piezoelectric linear displacement accumulating high-power density actuator is established, and the reliability of the virtual prototype model is verified by comparing with the experimental data. In order to make the actuator with the lightest weight under the requirements of wing deployment, Isight and Adams co-simulation were used to optimize the parameters of the piezoelectric actuator, such as the outer diameter, length, and excitation frequency. Finally, the output power of 50.8 W/kg is achieved, which is comparable with the power density of the existing servo motor.

Progressing towards high performance non-resonant piezoelectric stepping actuators

Piezoelectric actuators are emerging as a promising technology with their potential to deliver a system with high specific power, accuracy, quick response and resolution. Over the years, there have been significant advancements towards enhancing the working stroke through motion accumulation (stepping) mechanisms, along with the attempts to achieve higher output force, motion speed and resolution. Among these output performances, speed and force are the two key parameters which determine their potential for medium to large-scale applications. Therefore, this paper provides a comprehensive review on these two main development directions of the stepping actuators, in which the adopted design concepts are analyzed in detail. Additionally, the challenges towards the implementation of these actuators for the targeted application are highlighted along with their feasible solutions. This review aims to provide an insight into the novel design of piezoelectric actuators, geared towards extending their potential for high power applications in the future.

Design and dynamic analysis of a novel compound bending hollow piezoelectric beam miniature rotary actuator

In this paper, a miniature hollow piezoelectric beam rotary actuator is proposed and designed based on the compound bending vibration modes. The structure body is designed as an elastic hollow square beam with symmetrical piezoelectric patches attached at both ends, which directly eliminates the step of the frequency tuning. A conical rotor is driven by the hollow piezoelectric beam through the elliptical motions of the points on its inner surface. Based on the Timoshenko beam theory and Lagrange equation, the numerical continuum model is established to analyze the working mechanism. A prototype of the miniature rotary actuator with a size of 50 × 6 × 6 mm (2 mm through-hole) is manufactured and its performance under various excitation parameters is characterized in rotor speed experiments. The experimental results show that the maximum speed of the conical rotor is 913 rpm at the excitation voltage of 400 V. With a maximum load of 70.31 mN, the spherical rotor can achieve a speed of 450 rpm. The numerical results are in great agreement with the experimental results, so the output characteristics of the rotary actuator can be estimated. The simulation and test results demonstrate that the proposed rotary actuator has outstanding output performance and controllability. In addition, the simple structure design is easy to realize the frequency tuning and miniaturization.

A Bionic Type Piezoelectric Actuator Based on Walking Motion and Asymmetrical L-Shaped Flexure Mechanisms

A bionic type piezoelectric actuator based on the walking motion of L-shaped flexure mechanisms has been proposed. By mimicking the walking motion of “human legs,” the proposed actuator is able to not only eliminate the backward motion to improve the motion efficiency, but also achieve the large working stroke with high output load easily. The special L-shaped flexure mechanism is employed as the “leg,” and the bionic walking motion is realized by applying two L-shaped flexure mechanisms alternately. The driving principle of the proposed piezoelectric actuator is discussed in detail, and the simulation is carried out to study the feasibility. An experimental system has been set up to investigate the actual working performance. According to the experimental results, the suitable phase difference between the two L-shaped flexure mechanisms to eliminate the backward motion is around <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> = 5°, the maximum speed is <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> = 1887.3 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m/s, the minimum stepping distance is 0.084 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m, and the maximum load is more than <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">F_v</i> = 1100 g. The motion speed and the maximum load under the proposed bionic walking motion (two flexure mechanisms work together as “legs”) could be improved greatly for almost 3.7 and 1.7 times, respectively, compared with that of the traditional friction–inertial motion (only one flexure mechanism works). By eliminating the backward motion, the motion efficiency is improved about 52.9% under the condition of 120 V and 1 Hz. This article shows the feasibility of applying the bionic motion to improve the performance of piezoelectric actuators, which may be instructive for the design of piezoelectric actuators with large working stroke. In the future, it may be helpful for the real application of piezoelectric actuators in the fields of ultraprecision machining, optical engineering, and aerospace technology.

Textured BiScO3-PbTiO3 piezoelectric ceramics with both high electromechanical coupling factor and high curie temperature

High-temperature piezoelectric devices require piezoelectric ceramics with high Curie temperatures and high-temperature stability of piezoelectric properties to avoid the depolarization of piezoelectric ceramics during application. However, piezoelectric materials with high Curie temperatures usually have restrained piezoelectric properties. Crystallographic orientation via texture engineering is a practicable way to improve piezoelectric performance. Here, we propose a sintering-aid-assisted template grain growth strategy to texture BiScO3-PbTiO3 ceramics to overcome the low orientation issue that challenges the texturing of BS-PT for decades. By judiciously selecting B2O3-CuO as sintering aids, we fabricated highly ⟨001⟩-textured 0.43BS-0.57PT ceramics with Logtering factors &amp;gt;99.0% that possess high piezoelectric coefficients d33 of 474–612 pC/N while maintaining relatively high Curie temperatures of 370–402 °C. Importantly, this work addresses a long-standing issue presented in BS-PT ceramics, i.e., the low electromechanical coupling property of BS-PT ceramics (k33 &amp;lt; 0.70) by improving the electromechanical coupling factor k33 to 81.2%. The newly designed textured BS-PT ceramics are thought to be promising candidates for the design of high-temperature piezoelectric transducers and actuators.

Design of Piezoelectric Inertial Actuator with Wedge‐shaped Foot Structure for Cell Manipulation

AbstractAiming at the performance requirements of positioning accuracy and stability of piezoelectric inertial actuators in fields including micro‐operation and biomedical engineering, a piezoelectric inertial actuator with wedge‐shaped friction foot structure using bimorph films is proposed in this paper. The wedge‐shaped friction foot structure can adjust the friction force in different driving stages, which suppresses the backward motion and effectively improves the output performance of the actuator. And the bimorph films are processed by Micro Electromechanical Systems (MEMS) manufacturing process technology. It enables the actuator to move steadily with a small tip mass and facilitates the miniaturization of actuator. The simulation model is constructed based on the dynamic model of actuator and the prototype parameters are optimized from the results of simulation tests. Then a series of output performance experiments are carried out. Experimental results show that the proposed actuator has the advantages of high resolution, stability, and displacement linearity. And the highest resolution of 0.035 µm is achieved. Depending on above results, the cell drug injection simulation experiments are successfully conducted. The success of experiments shows that the prototype has good output performance and great application potential and value in the field of cell manipulation.

Design, analysis, and experimental study on a novel inertial piezoelectric actuator with double-stator cooperative motion

To realize high performance and suppress the backward motion of the inertia piezoelectric actuator, a novel inertial piezoelectric actuator with double-stator cooperative motion is proposed, designed, fabricated, and tested. The structure and the operation principle of the proposed actuator are first explained in detail. Then the flexible structure is analyzed through the finite element simulation. In addition, the dynamic model of the actuator with double-stator working mode is established and simulated in MATLAB/Simulink, and the step characteristic is investigated, which provided a guidance for the design and optimization of inertial piezoelectric actuators with double-stator. Finally, an experimental investigation of the proposed actuator prototype was carried out and the results showed a significant improvement in the performance of the proposed actuator compared to the previous double-stator inertial piezoelectric actuators. The actuator exhibits a maximum speed of 32.84 mm/s, a maximum lateral load of 20 N, a maximum vertical load of 200 N, a minimum backward rate of 0.91%, and a minimum resolution of 127.5 nm. The actuator with double-stator can improve the maximum output performance to a certain extent, and suppress the backward rate, presenting a specific reference value for the design of future high-performance piezoelectric actuators.

On the design of piezoelectric actuator for 1D MEMS scanning mirror applications

This study presents the design, implementation, and characterization of 1D resonant type micro-electro-mechanical-systems (MEMS) piezoelectric scanning mirrors with different actuator designs to investigate their influences on the figure of merits (FoMs) for automotive light detection and ranging application. The MEMS scanning mirrors are driven by lead zirconate titanate (PZT) thin film in this study owing to its outstanding piezoelectric properties. Three different beam-type piezoelectric actuators are designed, including the reference meander straight-beam actuator design, and the proposed meander curved-beam and straight-curved tapered beam actuator designs. Simulations show the scan angle enhancement for two proposed designs, yet the resonant scanning frequency of meander curved-beam design dropped to below the 2 kHz requirement. To evaluate the designs, scanning mirrors with two proposed actuators are fabricated and tested. Measurements show that the resonant frequencies for the two proposed MEMS scanning mirrors are 1735 Hz and 2578 Hz, respectively. Two proposed designs respectively have the maximum optical angles of 48.1° and 50.6° at the 20 Vpp driving voltage. Due to the much higher stress on the beam structure induced by the misalignment of PZT film, the actuator could not reach the predicted scanning angle of near 80°. In comparison of the two proposed designs, the straight-curved tapered beam actuator design could enhance the FoM for about 56%. In summary, the performances of piezoelectric MEMS scanning mirror can be improved by varying the designs of length and shape of actuator, and the distribution of PZT film on the suspended actuator is also a critical design concern.

Design, analysis and experimental performances of a multi-mode friction inertial piezoelectric actuator

To enrich the output performances and application fields of friction inertial piezoelectric actuators, a multi-mode friction inertial piezoelectric actuator was proposed. It had three driving modes, i.e. the inertial stick-slip mode, the inertial impact mode and the compound driving mode. An integrated flexible mechanism (IFM) consisting of the lever-shaped flexible mechanism (LSFM) and the butterfly-shaped flexible mechanism (BSFM) was designed for achieving these three driving modes. Theoretical analysis of the IFM was performed by using the matrix-based compliance modeling method and the response surface methodology. An experimental system was established to test the output performances of the actuator under various driving modes. Experimental results indicated that the actuator in three driving modes presented different output performances, and the output displacement in the compound driving mode was equivalent to the sum of those in the two single inertial modes. In the compound driving mode, the actuator achieved larger step displacement, and it also achieved good speed, loading capacity as well as motion stability. For instance, the maximum speed was 10.04 mm/s at 250 Hz in the compound driving mode, while they were 5.06 mm/s at 250 Hz in the inertial impact mode and 10.81 mm/s at 450 Hz in the inertial stick-slip mode. Furthermore, output performances of the actuator could be easily tuned in the compound driving mode when two driving voltages were controlled separately, which provided an idea for achieving the linear smooth motion.

Modeling and Design Optimization of a New Piezoelectric Inchworm Actuator with Screw Clamping Mechanisms.

A new piezoelectric inchworm actuator with screw clamping mechanisms has been developed recently for the wing folding mechanism of a small unmanned aircraft where the actuator power density is a great concern. Considering that the prototype actuator was designed just with engineering intuition and the performance optimization through experimental developments would take a vast amount of cost and time, a mathematical model was developed to investigate the actuator's critical design parameters and optimize its presently undesirable performance. Based on the lumped parameter method reported previously, and taking full account of the detailed modeling of the complex actuator housing and the actual nonlinear behaviors from the high-force contact and friction occurring at the screw-nut interface, as well as the output performance of the main drive elements including the piezoelectric stack and hollow ultrasonic motors (HUSMs), this model was built and then was experimentally verified for its accuracy and availability. Finally, nine design parameters were studied for their individual effect on the actuator's output using the proposed model. The simulation results indicate that the performance can be considerably improved by performing a slight modification to the prototype, and the dynamic modeling and parameter optimization methods used in this study can also serve as a useful reference for the design of similar piezoelectric inchworm actuators with intermittent clamping behaviors.

Design and experimental performance of a novel piezoelectric inchworm actuator based on screw clamping principle.

The requirements of large thrust in bidirectional motion, high specific power (power/weight ratio), reliable self-locking at power off state, and compact size envelope for various applications of existing piezoelectric actuators are still urgent. To address these challenges, this study makes full use of the piezoelectric material's excellent dynamic performance, robust force output, and high energy density to propose a novel inchworm piezoelectric actuator, which relies on the alternate clamping of two nuts independently rotated by two ultrasonic motors on a feed-screw in accordance with a piezoelectric stack (piezo-stack) excitation to accumulate the piezo-stack's electric field-induced strain periodically and realize power output. The operation principle and design process of the presented actuator were elaborated, and a prototype was fabricated and experimented. Results indicate that the actuator has achieved an expected bidirectional motion for powering the tensile load and compressive load, attained a micrometer-sized step resolution, produced a 3.08 mm/s free speed, a 700 N stall load, and a 1.34 W/kg specific power, and shown a favorable prospect for further development.

An Inertial Impact Piezoelectric Actuator Designed by the Asymmetric Friction Principle and Achieved by Laser Texturing of the Driving Feet

An asymmetric friction principle is newly proposed for the design of inertial impact piezoelectric actuators. There are two ways to achieve asymmetric frictions: either by tuning the positive pressure or by tuning the friction coefficient. Compared with tuning the positive pressure by an asymmetric structure, the structural parameters can be reduced by employing a symmetric structure and tuning the friction coefficient. In this study, an asymmetric friction inertial impact actuator was developed using a symmetric compliant mechanism (SCM), and the asymmetric frictions were realized by laser texturing of the driving feet at one end of the SCM. Four kinds of microstructures were initially fabricated on the driving feet, and their friction properties were experimentally tested. Accordingly, two kinds of microstructures, namely Ta and Tb microstructures, were selected. Output characteristics of the actuator with these two microstructures were measured and comparatively analyzed. The experimental results indicate that the actuator could achieve stable step motion, and the output characteristics were affected by the fabricated microstructure, as it determined the friction coefficient. The actuator with the Tb microstructure achieved a maximum speed of 2.523 mm/s, a resolution of 188 nm, a vertical loading capacity of 2 N and a horizontal loading capacity of 0.6 N, whereas the actuator with the Ta microstructure had a higher resolution of 74 nm. This study provides a novel idea for the design of asymmetric friction inertial impact actuators by tuning the friction coefficient.

Design, simulation, and motion characteristics of a novel impact piezoelectric actuator using double stators

This study presents a novel impact piezoelectric motor that excites double stators through a sinusoidal signal. A sawtooth signal drives the traditional impact piezoelectric actuator, and its working frequency is limited by the resonant frequency. This study uses sine signals to drive the double stators to produce a sinusoidal vibration. The sinusoidal vibration of different frequencies and amplitudes are synthesised into a sawtooth vibration on the stage plate. The directional movement of the slider is realised using the vibration of the stage plate to drive the slider. This structure reduces the space required for the piezoelectric actuator to work. The working principle of the motor is discussed, and the structure is constructed. The dynamics model of the whole system is established on the based of the dynamics model of the actuator and the LuGre friction model. Moreover, the dynamics model was simulated and analysed through MATLAB/Simulink. The prototype is fabricated and tested. Experimental results confirm the effectiveness of using sinusoidal signals to drive the piezoelectric actuator, and the motion process of the piezoelectric motor is consistent with the theoretical analysis. The maximum speed of the piezoelectric actuator is 5.54 mm s−1, and the resolution is 0.72 μm. This study provides an effective driving method for the quasi-static piezoelectric motor to improve the working frequency.

Design, fabrication, and characterization of piezoelectric single crystal stack actuators based on PMN-PT

A piezoelectric stack actuator (PSA) consisting of 28 lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal layers is developed. The free stroke and blocking force, which are the figures of merit of a PSA, are simulated through finite element analysis. The free stroke of the PSA samples measured using a laser displacement sensor was in the range of 6.4–8.0 µm at 200 V. In addition, the blocking force of the PSA samples measured using a custom-made system, consisting of a strain gauge, a motor and a load cell, was in the range of 191–226 N at 200 V. An analysis of seven samples exhibited that a large free stroke resulted in a blocking force of the PSA.

Design and performance of a compact stick-slip type piezoelectric actuator based on right triangle flexible stator

In the field of stick-slip type piezoelectric actuators, the actuator with simple and compact structure has been given significant research and design value. A compact stick-slip piezoelectric actuator based on right triangle flexible stator is proposed and evaluated in this work. The proposed actuator only includes a right triangular type stator inserted with a PZT stack and it has the merit of simple structure. The PZT stack is excited under a sawtooth waveform voltage, and the elongation deformation of the PZT stack makes the driving foot move obliquely due to the right triangular stator. The slider is pressed under the vertical component of the oblique movement, while the slider is actuated under the horizontal component simultaneously. The working principle of the proposed actuator is illustrated by theoretical and simulation methods in detail. The proposed actuator is fabricated and its output characteristics are measured. The experimental results show that the maximum output speed of the developed actuator is 4.6 mm s−1 when the voltage and frequency are 100 V and 720 Hz. It has the merit of simple design and relatively better performance by series of comparisons with some existing works.

A Linear Piezoelectric Actuator Using "A-Shaped" Structure.

A new design of linear piezoelectric actuator using "A-shaped" structure was proposed, designed, fabricated, and tested. By fusion design of the piezoelectric transducer and the mechanical structure, the proposed actuator only uses the first bending vibration of the center piezoelectric transducer to work. Frequency degeneration is no longer needed, which enables the actuator to adjust its structural parameters according to the application conditions. When applying an alternating voltage at resonance frequency, the center piezoelectric transducer will be stimulated in the first bending vibration. The vibration energy transmitted to the two driving arms generates alternating tilting movements with a phase difference of 180° between the two driving feet, which enables the actuator to push the linear guide when a vertical preload is applied. Under the preload of 120 N, the actuator gained a maximum thrust force of 9.8 N and a maximum output power of 0.62 W with a self-weight of 0.061 kg. The maximum output thrust density and the maximum output power density were 160.6 N/kg and 10.2 W/kg, respectively.