Linear Piezoelectric Actuator Research Articles

Design of a piezoelectric pneumatic linear actuator in cell manipulation

A pneumatic piezoelectric linear actuator (PPLA) is proposed, which possesses the advantages of low power consumption, environmental friendliness, and high linearity of positioning. The prototype of the PPLA consists of a piezoelectric gas pump with serial chambers and a cylinder. The piezoelectric gas pump with serial chambers is designed with a wedge valve and flexible support structure, which results in high output performance and meets the working requirements of pneumatic linear actuators. Prototypes of PPLA are designed and manufactured. Experiments are conducted to investigate the effect of chamber height, driving voltage, and driving frequency on the performance of the PPLA. The experimental results indicate that increasing the chamber height enhances the output performance of the PPLA. At 250 Vpp and 120 Hz, the PPLA achieves a maximum output velocity of 16.62 mm/min and is able to handle a maximum load of 11 N. Additionally, an injection simulation experiment using zebrafish embryos is conducted, which confirms the high control accuracy and linearity of the PPLA. The experiment demonstrates the potential application of the PPLA in the field of cell manipulation.

Research and design a model of 2D profile generation system applied in laser welding technology using piezo linear actuators

The article introduces a method to create any 2D laser profiles applied in welding technology. This method allows for the creation of profiles that best suit the weld characteristics and material of the weld workpiece, thereby improving the quality, accuracy, and aesthetics of the weld and increasing laser welding efficiency. In the study, the authors proposed a model of a 2D laser profile generation system with a reflecting mirror and two piezoelectric linear actuators. The forward and inverse kinematic equations were completely solved, while a control algorithm was proposed to control the motion of linear actuators. The model is simulated on MATLAB with circular, sin-wave, and 8-figured profiles. The obtained results show that the control profiles are almost close to the desired ones (both shape and scan period). There is a displacement between them. With the given simulation parameters, the displacements of the above-mentioned profiles are 0.03 mm (1.5%), 0.05 mm (2.5%), and 0.05 mm (1.25%), respectively. This shifting can be reduced by increasing the number of samplings. The simulation results provide strong evidence for the feasibility of implementing a practical 2D laser profile generation system based on the proposed model.

Modeling and Control of a Linear Piezoelectric Actuator

To improve the output displacement of piezoelectric actuators, a linear piezoelectric actuator based on a multistage amplifying mechanism with a small volume, large thrust, high resolution, high precision, and fast response speed is proposed. However, inherent nonlinear characteristics, such as hysteresis and creep, significantly affect the output accuracy of piezoelectric actuators and may cause system instability. Therefore, a complex nonlinear hysteresis mathematical model with a high degree of fit was established. A Play operator was introduced into the backpropagation neural network, and a genetic algorithm (GA) was used to reduce the probability of the fitting of the neural network model falling into a local minimum. Moreover, simulation and experimental test platforms were constructed. The results showed that the maximum displacement of the actuator was 558.3 μm under a driving voltage of 150 V and a driving frequency of 1 Hz. The complex GA-BP neural network model of the piezoelectric actuator not only exhibited high modeling accuracy but also solved the problems of strong randomness and slow convergence. Compared with other control algorithms, the GA-BP fuzzy PID control exhibited higher control precision.

Research on variable stiffness asymmetrical resonant linear piezoelectric actuator based on multi-modal drive

In this paper, a linear piezoelectric motor with variable stiffness and asymmetric resonance is proposed, which is driven by a single harmonic signal. Working in the resonant state improve the output performance of the motor. Motor control is relatively simple and can realize reverse movement under the driving of second-order single harmonic signal. At the same time, the new motor can obtain different operating speed and step distance by changing the clamping position in front and back to meet the requirements of different loads and different working conditions and has strong applicability. By experiment, the first-order optimal operating frequency of the motor prototype at three different stiffness adjustment positions is 88 Hz, 90 Hz and 92 Hz respectively. Under the excitation of 240 Vp–p first-order resonance signal, the corresponding output speed of the motor prototype is 16.116 mm s−1, 20.457 mm s−1 and 25.015 mm s−1 respectively, and the corresponding displacement resolution is 0.18 mm, 0.22 mm and 0.27 mm respectively. When the stiffness adjustment positions is 2 mm, the maximum load of the motor prototype reaches 450 g. The second-order optimal operating frequency at the stiffness adjustment positions 1 mm is 601 Hz. Under the excitation of a 240 Vp–p second-order resonant signal, the reverse output speed of the motor prototype is 13.126 mm s−1, and the corresponding displacement resolution is 0.02 mm.

Solar Panel Cleaning System Using Smart Hybrid Embedded Systems with IoT Assistance

The solar panel cleaning system utilizes a rechargeable battery and is activated by a switch through a mobile application. The cleaning tool is moved horizontally by pressing a button in the mobile application and sends an output signal to the gear motors using internet access. Cleaning solar panels on a commercial and industrial scale can be difficult due to the lack of readily available water and power sources. Rooftops, carports, and other elevated structures provide unique cleaning challenges. A solar panel cleaning system based on a Linear Piezoelectric Actuator (LPA) is intended to enable a solar panel to operate in optimal power-producing conditions regardless if employed in a gross climate. The energy flow, the solar power source, the supercapacitor-battery hybrid storage system, and the load are effectively managed using a Support Vector Machine (SVM)-based load predictive energy management system. Hence, LPA-SVM is a solar panel cleaning system that can diminish dirt accumulating on the surface. Cleaning solar panels may improve performance by removing dust, dirt, and pollutants like leaves and bugs. Clean the contaminants with water and a soft, non-abrasive sponge and towel for optimal results and to avoid damaging the solar panels in the accessibility.

Rod-Shaped Linear Inertial Type Piezoelectric Actuator

This article presents a numerical and experimental investigation of a novel rod-shaped linear piezoelectric actuator that consists of a square cross-section-shaped rod with eight piezo ceramic plates and a cylindrical guidance rail. The rod has a hollow cut made with an offset from the longitudinal axis of the symmetry. A cylindrical guidance rail is placed on one side of the rod, while T-shaped clamping is formed on the opposite side. The slider is mounted on the rail and is moved along it. The actuator is compact, making it possible to mount it directly on a printed circuit board (PCB) or in another device with limited mounting space, restricted mass, or actuator footprint. The operation of the actuator is based on the excitation of the first longitudinal vibration mode of the rod that induces in-plane bending vibration of the nodal zone of the rod due to a hollowed cut asymmetrically placed in the central part of the actuator. The actuator is driven by two sawtooth waveform electric signals with the phase difference of π that allows exciting longitudinal deformations of the rod and controls the reverse motion of the slider. The results of numerical investigations confirmed the operation principle of the actuator at the frequency of 59.72 kHz. The maximum displacement amplitude of the guidance rail in the longitudinal direction reaches up to 152.9 μm while the voltage of 200 Vp-p was applied. An experimental investigation of the actuator was made, and a maximum linear speed of 45.6 mm/s and thrust force of 115.4 mN was achieved.

Development of inertial piezoelectric linear actuator with asymmetric design

This article represents a numerical and experimental investigation of a piezoelectric linear actuator with asymmetric design. The actuator is based on a square-shaped rod with asymmetrical cut and T-shaped clamping. The cylindrical rail, with slider, is on the opposite side of the T-shaped clamping. The low-volume and mass of piezoelectric actuator allows to mount it directly to printed circuit board (PCB). The actuator operation is based on the inertial stick – slip operation principle inducted by the first longitudinal vibration mode excited by two sawtooth signals with phase difference π. Furthermore, the longitudinal vibration mode induces bending deformations of the rod, increasing the displacements of the cylindrical rail. The results of numerical and experimental investigations have validated the actuator operating principle, as well as shown that the displacement amplitudes of the guidance rail have reached 153.6 μm at the 200 Vp-p excitation signal amplitude, while the linear motion speed reached 45.6 mm/s at the same excitation signal.

A High-Power-Density Piezoelectric Actuator Operating in Bicycling Movement Mechanism

Comprehensive high-precision actuations are in growing demand to meet diversified needs in scientific and industrial fields. However, it is a great challenge for piezoelectric actuators with compact structure to guarantee high load capacity and wide velocity range (including fast motion velocity and high resolution) simultaneously. Herein, inspired by bionic methodology, a high-power-density bar-type linear piezoelectric ultrasonic actuator (LPUA) operating in the single second bending (<i>B₂</i>) mode with elaborate working principle is developed by imitating bicycle movement mechanism. The proposed <i>B₂</i>-LPUA actuator is simple, and easy for miniaturization without multimodal decoupling problem. Under only one-phase voltage drive, the miniature bar-type actuator can produce continuously bidirectional motions with the maximum driving velocity, minimum driving velocity, load, and output power of 211.2 mm&#x002F;s, 3.3 &#x03BC;m&#x002F;s, 5.4 N, and 218.3 mW, respectively, and the tested minimum step displacement is only 33 nm in open-loop control. Especially, its output power density (243 mW&#x002F;cm³ or 4.112 mW&#x002F;cm³.kHz) is at least twice larger than most reported LPUAs. The experimental results indicate that the proposed piezoelectric actuator with excellent actuation performances has broad application scenarios, and its bionic motion design method would have inspirational significance for creating new piezoelectric devices with more attractive properties.

A novel inchworm piezoelectric actuator using two-stage amplification mechanism with high speed: design, modeling, and experimental evaluation

The inchworm piezoelectric actuator has a wide application prospect in the field of precision instruments. However, in view of the complex structure of the existing inchworm piezoelectric actuator and the far distance between the driving feet of the actuator, it is difficult to realize alternate driving and the high output speed of the driving feet, etc. In this paper, an inchworm piezoelectric linear actuator based on two-stage amplification mechanism is designed, which amplifies the output displacement of the driving feet by two-stage amplification mechanism, and improves the driving efficiency of the actuator stator by the way of alternating driving. We present an inchworm piezoelectric actuator with three piezoelectric stacks and a two-stage amplification mechanism, which is simple in structure design, compact in actuator structure and easy to realize alternate driving. The kinematics and dynamics models of the inchworm piezoelectric actuator are established by analyzing the flexible hinge and its structure with the pseudo-rigid body method. The length of the lever structure and the angle of the triangular structure of the piezoelectric actuator are solved by kinematics, and the natural frequency of the whole structure is calculated by dynamics. Through finite element analysis, the simulation magnification ratio of the piezoelectric actuator is obtained, so as to evaluate and verify the theoretical calculation and further optimize the structure. The experimental results show that the inchworm piezoelectric linear actuator using two-stage amplification mechanism has a high driving speed of 5.53 mm s−1 under voltage of 135 V and frequency of 70 Hz.

Design and experiment of a large displacement linear piezoelectric actuator

To increase the output displacement of the linear piezoelectric actuator, a linear piezoelectric actuator with large displacement and three operation modes is proposed. The operating principle of the piezoelectric actuator is presented. The magnification factor of the displacement amplification mechanism is deduced and verified by finite element analysis. To improve the output precision of the actuator, a feedforward PID control model is established. Based on the experimental test platform, the output characteristics of the piezoelectric actuator are tested. Results show the maximum output displacement of the piezoelectric actuator is 558.3 μm under a driving voltage of 150 V with two piezoelectric stacks. When the driving frequencies are less than 3 Hz, the control accuracy of feedforward PID is higher than that of PID, and the error between the measured displacement and the ideal value is less than 10% after applying the control to the piezoelectric actuator.

Transient measurement of mechatronic multi-parameters and kinetics performances for linear piezoelectric motors

Due to the time-dependent correlations, the measurement and characterization of electronic and mechanical parameters are critical for linear piezoelectric ultrasonic motors (USMs) during the running process. This study constructed a homemade system to measure the electromechanical multi-parameters and kinetics performances agilely, transiently, and synchronously. The principles and structures of the test system were demonstrated based on virtual instrument technology. A signal conditioning circuit is designed and used for physical signal processing, A/D conversion, and transmission. The difference in resonant frequencies was discovered for the synchronization acquisition of mechatronic parameters, and the instantaneous characteristics of electromechanical parameters for SWUM (e.g., driving voltage, input current, thrust force, and speed during the start-up and power-off process) were established based on the experimental data. This study is significant for the measurement/evaluation of the dynamic and transient performances of linear piezoelectric motors and actuators.

Development of a multi-drive-mode piezoelectric linear actuator with parallel-arrangement dual stator

To realize the performance of large stroke, smooth motion with less wear, and high positioning resolution, a non-resonant piezoelectric linear actuator based on a parallel-arrangement dual stator was developed in this study. The proposed actuator could achieve the multi-drive mode with different voltage signals, including co-drive, alternate-drive, and precision positioning mode. A prototype was fabricated, and a series of experiments were tested to evaluate its output performance under three driving modes. The experimental results indicated that, under the alternate-drive mode, when a voltage of 50 Vp-p and a preload of 8.6 N were applied to the proposed actuator, a no-load speed of 0.06–1.2 mm/s at driving frequencies of 10–500 Hz and a stepping displacement of 1.8 μm at 1 Hz were achieved; A maximum thrust of 7.3 N at 100 Hz and a maximum no-load speed of 16.1 mm/s at 3000 Hz were obtained under a voltage of 100 Vp-p and a preload of 20.8 N. Moreover, under the precision positioning mode, the nanoscale positioning resolutions of 156 and 172 nm in forward and reverse motions were achieved, respectively. Thus, the proposed actuator is expected to be applied for driving the aperture of a scanning electron microscope.

A Linear Piezoelectric Actuator Based on Working Principle of Three-Petal Mouth of a Rabbit

A ring-shaped linear piezoelectric actuator with three driving teeth is proposed and designed based on an axial-radial bending coupling vibration mode. The coupling vibration mode is neither pure axial bending mode nor pure radial bending mode, but an axial-radial bending hybrid one, which is generated by only one group of PZT elements and one exciting signal under an asymmetrical fixed boundary condition. The working principle of the proposed actuator is similar to the opening and closing actions of the three-petal mouth of a rabbit, which is analyzed by the finite element method. Then, the coupling vibration mode is verified by a scanning laser Doppler vibrometer after the fabrication of a prototype. Experimental results show that the prototype can achieve a maximum velocity of 60.46 mm/s and a displacement resolution of 0.5 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m, and the velocity of the linear actuator can be smoothly adjusted in a wide range of 0.005–60.46 mm/s. In addition, the actuator can drive a hollow cylinder mover along different slopes without other auxiliary structures. The simulated and experimental results confirm that the proposed ring-shaped actuator is feasible without any guiding structure, which has great potential to realize further miniaturization of linear piezoelectric actuators.

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.

Tunable Quasi-Reflectionless Bandpass Filters Using Substrate Integrated Coaxial Resonators

This brief reports on the electromagnetic (EM) design and the practical development of frequency-reconfigurable quasi-reflectionless bandpass filters (BPFs) using substrate integrated coaxial (SIC) resonators. The filter concept is based on in-series-cascaded quasi-reflectionless stages that are shaped by a first-order bandpass section and two resistively-terminated first-order bandstop sections. For the first time, we explore the realization of these filters using tunable SIC resonators that exhibit high quality factor ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula> ) and can be widely tuned with commercially-available linear piezoelectric actuators. Synthesized examples alongside various EM design and practical integration aspects are discussed in detail. The concept is experimentally validated at S-band through the manufacturing and testing of two reconfigurable (one-stage and two-stage) prototypes.

A Novel Type of Noncontact Linear Piezoelectric Actuator Modulated by Electromagnetic Field: Design and Experiment.

To explore a noncontact drive solution for linear piezoelectric actuators, a novel type of noncontact linear piezoelectric actuator modulated by the electromagnetic field is proposed. The proposed actuator employs electromagnetic force to modulate and transfer the locomotion between the stator and the runner. The drive scheme reduces the wear and friction between the stator and the runner and can control the coupling force by the electric system. Here, the design pattern and working principles are described. The amplification ratio equation of the flexible amplification mechanism is established, and the calculation method of the dynamic electromagnetic force is illustrated. For assessing the validity and measure the output characteristics of the proposed actuator, a prototype is fabricated to measure the output speeds, the stepping distances, and the output forces. The experimental results show the actuator with the driving frequency of 1 Hz, the electromagnetic modulation voltage of 4 V, and the piezoelectric driving voltage of 100 V can continuously output a stall load force of about 0.15 N and speed of 0.33 mm/s.

Frequency Agile Slot Antenna Using Contactless Capacitive Loading

With the development of modern wireless systems, the spectral environment has become increasingly crowded. This has spawned a strong interest in frequency, bandwidth, and pattern reconfigurable antennas, which can adaptively tune their response to reduce interference. Most recent development in frequency reconfigurable antennas has focused on tuning by use of microelectromechanical systems, pin diodes, or varactors. However, these tuning techniques are ill-suited for high power applications due to breakdown, non-linear effects, and other performance issues. These problems can be solved by the use of mechanical tuning. In this paper, a piezoelectric linear actuator tuned slot antenna is presented. The design is based upon changing the capacitive loading of a slot antenna, and thereby increasing the electrical length, through physical displacement of a metal plate. The antenna was simulated, fabricated, and measured to tune a full octave from 2-4 GHz while maintaining a maximum return loss of greater than 9.0 dB. Simulations also show a 65.74% to 95.75% radiation efficiency across S-band. A broadside realized gain of greater than 1.73 dB was measured over the entire tuning range. Moreover, the tuning mechanism was proven robust above other methods by withstanding up to 100 W of power incident on the feed at 3 GHz.

Achieving smooth motion and high-speed for piezoelectric stick-slip actuator based on the two-stage lever principle.

With the development of the precision manufacturing industry, actuators' performance requirements are increasingly demanding. However, stick-slip actuators still have the problems of backward motion and low motion speed at low frequencies. In this paper, to decrease the backward motion and achieve high speed at low frequencies, a linear piezoelectric stick-slip actuator is designed based on the two-stage lever principle. Theoretical and numerical investigations are used to optimize the flexible hinge of the stick-slip actuator. Experimental results indicate that the motion slider can achieve a smooth motion. The backward rate can even drop to 0. The maximum motion speed was 124.83 mm/s at 1600 Hz. The motion speed of the designed actuator was higher than that of previous stick-slip actuators at the same frequency. In addition, the load capacity of the prototype is tested. Based on different loads, the load matching is achieved by an auxiliary piezoelectric-stack, where the maximum horizontal load was 2.3 N. According to the comparison with previous actuators, the designed prototype can achieve high speed at low frequencies. Furthermore, the displacement curves show good smoothness. These characteristics will be helpful for the practical application of stick-slip piezoelectric actuators.

A stick-slip piezoelectric actuator with suppressed backward motion achieved using an active locking mechanism (ALM)

Backward motion commonly exists in the stick-slip linear piezoelectric actuator, resulting in deterioration of the output performance and limiting their applications. To solve the problem, a stick-slip linear piezoelectric actuator with suppressed backward motion, achieved using an active-locking mechanism (ALM) with two mechanisms, is proposed in this paper. One mechanism involves stick-slip driving, while the other actively suppresses backward motion by clamping the slider during the backward driving process through efficient control. A prototype actuator was designed and manufactured to verify the feasibility of this method, and an experimental system was established to obtain the detailed parameters. Also, to verify the feasibility and effectiveness of the suppression effect on backward motion of the proposed actuator, the output performance of the traditional stick-slip actuator and the actuator with the ALM were compared. Based on the results, we demonstrate that the maximum output speed and maximum output force of the prototype are 2.26 mm s−1 and 1.6 N under a voltage of 100 V, respectively.

A Digitized Representation of the Modified Prandtl-Ishlinskii Hysteresis Model for Modeling and Compensating Piezoelectric Actuator Hysteresis.

Piezoelectric actuators are widely used in micromanipulation and miniature robots due to their rapid response and high repeatability. The piezoelectric actuators often have undesired hysteresis. The Prandtl–Ishlinskii (PI) hysteresis model is one of the most popular models for modeling and compensating the hysteresis behaviour. This paper presents an alternative digitized representation of the modified Prandtl–Ishlinskii with the dead-zone operators (MPI) hysteresis model to describe the asymmetric hysteresis behavior of piezoelectric actuators. Using a binary number with n digits to represent the classical Prandtl–Ishlinskii hysteresis model with n elementary operators, the inverse model can be easily constructed. A similar representation of the dead-zone operators is also described. With the proposed digitized representation, the model is more intuitive and the inversion calculation is avoided. An experiment with a piezoelectric stacked linear actuator is conducted to validate the proposed digitized MPI hysteresis model and it is shown that it has almost the same performance as compared to the classical representation.