Piezoelectric Motor Research Articles

A Gated Two-Frequency Two-Mode Method for Piezoelectric Motorization

Abstract In this study, we present a new driving method to generate traveling waves in a finite plate for application to piezoelectric motors. Due to resonant modes which dominate the vibration of finite structures, methods to reduce resonant effects such as using an electric sinker or driving at a non-resonant frequency have been reported. To take advantage of natural resonance and to increase driving efficiency, a new method entitled gated two-frequency-two-mode (G-TFTM) was developed. A piezoelectric bimorph of 1.1 g weight with two rectangular actuators was implemented to verify the design concept. One actuator was operated at a first bending mode and the other actuator operated at a second bending mode with a phase difference. The driving signal was gated to generate an intermittent excitation to provide the periodic propulsion. To determine the profile of the induced traveling wave, an analytical solution was derived and a numerical model was used. Using these design tools, we experimentally verified that traveling waves can be generated using a G-TFTM method. A 0.1-g object can be moved at a speed of 3.31 mm/s under the condition of a 70-to-20 voltage ratio and a 137 deg phase difference. The moving direction was found to be reversed by changing the phase to −43 deg. The experimental and numerical data are detailed in this paper to demonstrate the feasibility of this G-TFTM method.

Experimental investigation and numerical modeling of piezoelectric bender element motion and wave propagation analysis in soils

The bender element (BE) test has been widely used for the dynamic characterization of soil specimens at low-shear strain levels. However, the actual behavior of the BE inside a soil specimen remains unknown. Thus, the current ASTM standard does not consider the interference of compressional and shear waves in BE testing, which can lead to significant errors in the evaluation of shear wave velocities. The main objective of this paper is to present a numerical model of the BE system to better understand the response of the BEs inside a soil sample. The model is calibrated, verified, and then used to demonstrate the importance of taking into consideration the interaction between compressional and shear waves for the correct interpretation of BE measurements. The model successfully captured the measured vibrations of the BE in air as well as inside transparent soils. More importantly, the numerical simulations provide a new understating of the significant interactions of P waves and S waves especially in clay soils. Thus, the proposed coupled piezoelectric and solid mechanics model can be used to study the soil–BE interaction so that sound recommendations can be given to improve the interpretation of BE tests in different soils.

Design of a Short-Beam Linear Traveling-Wave Piezoelectric Motor.

A straight short-beam linear piezoelectric motor constructed with two sets of ceramic actuators separated with the 1/4 wavelength interval is designed in this article. The piezoelectric ceramic actuators are fabricated in the whole body, which is driven by a two-phase circuit with the same amplitude but a phase difference of π /4. Traveling wave (TW) is formed by superimposing standing waves generated by each set of ceramic actuators. At the ends of the short beam, a wave-reduction mechanism with larger cross-sectional area is designed so that wave reflection is effectively diminished to preserve the TW. The currently developed short-beam linear piezoelectric motor is estimated, which can produce an ideal output speed of 169 mm/s while applying voltage of Vpp = 300 V at 45.49 kHz. Instead of operating as a stator to drive a carriage for example, the short-beam linear piezoelectric motor is implemented on a guide slider, and therefore, a linear piezoelectric motor stage is built. While driving the linear stage employed with a preload 300 GW and a friction coefficient of about 0.15, the propulsion force is measured about 4.8 N, the speed is about 56 mm/s, and the position resolution can achieve in the submicrometer scale.

Precision motion control of a piezoelectric cantilever positioning system with rate-dependent hysteresis nonlinearities

The study proposed a feedforward– feedback combined architecture to control a piezoelectric motion system with rate-dependent hysteresis nonlinearities. First, the feedforward control that considered the inverse rate-dependent Prandtl–Ishlinskii (RDPI) model was presented. Based on the inverse RDPI model, a formula that characterizes the output of the inverse compensation considering modeling errors and uncertainties was obtained. More precisely, the output of the inverse compensation of RDPI model consists of an invertible linear term and a bounded nonlinear term. Afterward, the feedforward control is extended with a feedback control architecture. In order to satisfy performance criteria in the presence of the uncertainties, the design of the feedback controller was based on the performances inclusion theorem from interval techniques. Experiments were conducted on a piezoelectric actuator to confirm the effectiveness of the combined feedforward–feedback control.

Inertial Piezoelectric Rotary Motor Based on Low Profile Stator with Trapezoidal Waveguides

Results of numerical and experimental investigations of a novel inertial piezoelectric rotary type motor based on a low profile stator with trapezoidal waveguides. The proposed motor has a simple design and is well scalable. Moreover, the proposed design of the motor allows mount it on a printed circuit board and use it in a small-size mobile positioning and actuating systems. The structure of the stator is based on a square type hollowed steel frame with four straight trapezoidal waveguides that are used to transfer vibrations of the stator to the rotation of the rotor. Piezo ceramic plates are glued on both sides of the stator. The thickness of the assembled stator is 0.9 mm, while the total area needed for stator mounting does not exceed 625 mm2. The driving of the rotor is based on the stick-slip principle, which is induced by excitation of the second in-plane bending mode of the four bimorph plates applying two saw tooth waveform signals with a phase difference by π. The numerical and experimental investigation was carried out to validate the operation principle of the motor and to measure the mechanical and electrical characteristics. The maximum angular rotation speed of 1304 RPM was achieved at a resonance frequency of 44.81 kHz when a preload of a 7.35mN was applied.

PID-type sliding mode-based adaptive motion control of a 2-DOF piezoelectric ultrasonic motor driven stage

This paper presents a new scheme of adaptive sliding mode control (ASMC) for a piezoelectric ultrasonic motor driven X–Y stage to meet the demand of precision motion tracking while addressing the problems of unknown nonlinear friction and model uncertainties. The system model with Coulomb friction and unilateral coupling effect is first investigated. Then the controller is designed with adaptive laws synthesized to obtain the unknown model parameters for handling parametric uncertainties and offsetting friction force. The robust control term acts as a high gain feedback control to make the output track the desired trajectory fast for guaranteed robust performance. Based on a PID-type sliding mode, the control scheme has a simple structure to be implemented and the control parameters can be easily tuned. Theoretical stability analysis of the proposed novel ASMC is accomplished using a Lyapunov framework. Furthermore, the proposed control scheme is applied to an X–Y stage and the results prove that the proposed control method is effective in achieving excellent tracking performance.

A Disc-Type High Speed Rotary Ultrasonic Motor with Internal Contact Teeth

This paper presents a disc-type ultrasonic piezoelectric motor, which is designed for micro flying vehicles. It provides a high output rotation speed under low operating voltage, compared with common piezoelectric devices, by employing a “contact teeth” wave transmission structure. The ultrasonic motor (USM) consists of a trimorph disc stator, with triple internal contact teeth, a shaft and two hemispheric hard-wearing rotors. The operating principle of the USM is based on the superposition of the in-plane B03 vibration mode of the trimorph disc, and the first longitudinal vibration of the contact teeth. An optimization method of the stator structure parameters was proposed and validated by numerical modeling. The diameter and thickness of the stator are 20 mm and 1 mm, respectively. A prototype with the weight of 2 g was made for this experimental test. The optimal frequency of the excitation signal and the preload force are 98.5 kHz and 0.5 N, respectively. The minimum operating voltage was tested under 7.5 V and reached the speed of 225 rpm, and the maximum unloaded rotational speed of the USM reached 5172 rpm when 30 V driving voltage was applied. The maximum lifting force generated by this USM was measured as 46.1 mN, which is 2.35 times bigger than its weight.

Simulation study of T-shaped piezoelectric linear ultrasonic motor based on PZT piezoelectric ceramics

In this paper, the T-shaped structure of linear ultrasonic motor was studied by means of establishing a THREE-DIMENSIONAL model of mechanical structure through SolidWorks and completing relevant simulation analysis through ANSYS Workbench. The finite element simulation analysis consists of four part: i. modal analysis, it determines the working mode and ensures that the frequency difference between the two working modes is as small as possible; ii. Harmonic response analysis furtherly verifies that the resonant response occurs at the operating mode frequency; iii. transient dynamic analysis demonstrates that the motion trajectory of the motor stator driving foot meets the theoretical requirements of ellipse shape. iv. drive signal and prototype are tested to verify the simulation analysis.

Performance comparison of two motion modes of a piezoelectric inertial linear motor and its potential application in cell manipulation

The piezoelectric inertial linear motor (PILM) has great application potential in cell manipulation, location of artificial neural electrode, and other micro-operation fields for its advantages of fast response, long stroke, and high resolution. However, the traditional schemes have been challenging to avoid the phenomenon of backward motion, which may lead to motion instability and failure of positioning in cell manipulation. To solve this problem, a novel PILM with two motion modes is proposed. In this study, throughin-depthanalysis of steppingcharacteristics, the reason why the motor with the traditional “forward–backward” motion mode is difficult to eliminate the backward motion phenomenon by adjusting the friction force in experiments is revealed. Then, a series of performance evaluation and cell manipulation simulation experiments are carried out. Experimental results indicate that the novel “forward–forward” motion mode can solve the backward motion problem and has the advantages of the speed, efficiency, and stability of the system, while the “forward–backward” motion mode has the advantages of resolution and carrying capacity. Moreover, the proposed motor can switch between the two motion modes freely according to the different requirements of the application environment for obtaining the required specific performance. Based on the above advantages and the successful druginjection simulation process in a zebrafishembryo, the proposed motor has great application potential in cell manipulation and other micromanipulation fields.

Modeling and simulation of bonded-type piezoelectric linear motors considering the stress transfer in adhesive layer

This paper provides a general framework for modeling bonded-type piezoelectric linear motors considering the stress transferred by adhesive layer. A three-dimensional static model of stator is first developed by the principle of minimum potential energy and finite element. The stress transferred by adhesive layer could be simulated and analyzed for arbitrary bonding conditions. Basing on the static stress-transfer analysis, a quasi-static stress acted to substrate by piezoelectric elements is assumed and integrated into the substrate dynamic model. A pure mechanical dynamic model is developed for the electromechanical coupling system of stator. Furthermore, the whole-machine dynamic model of motor is presented by incorporating the frictional contact force into the dynamic model of the stator and an analytical model of the mover. Finally, a bonded-type piezoelectric linear motor with V-shaped stator is investigated as an example for simulations and experiments. The methodology presented here for simulating the transferred load of adhesive layer in bonded-type piezoelectric motor as well as for estimating the vibration characteristics of stator and output performances of motor. It is believed that the proposed method would be helpful to design and manufacture the prototypes due to the wider applicability of allowing for irregular geometry and any bonding conditions.

Meshing Drive Mechanism of Double Traveling Waves for Rotary Piezoelectric Motors

Rotary piezoelectric motors based on converse piezoelectric effect are very competitive in the fields of precision driving and positioning. Miniaturization and larger output capability are the crucial design objectives, and the efforts on structural modification, new materials application and optimization of control systems are persistent but the effectiveness is limited. In this paper, the resonance rotor excited by stator is investigated and the meshing drive mechanism of double traveling waves is proposed. Based on the theoretical analysis of bending vibration, the finite element method (FEM) is used to compare the modal shape and modal response in the peripheric, axial, and radial directions for the stator and three rotors. By analyzing the phase offset and vibrational orientation of contact particles at the interface, the principle of meshing traveling waves is discussed graphically and the concise formula obtaining the output performance is summarized, which is analogous with the principles of gear connection. Verified by the prototype experimental results, the speed of the proposed motor is the sum of the velocity of the stator’s contact particle and the resonance rotor’s contact particle, while the torque is less than twice the motor using the reference rotor.

Measurement of quasi-static and dynamic mechanical properties of soft materials based on instrumented indentation using a piezoelectric cantilever

Instrumented indentation is a powerful in-situ mechanical characterization method and has been intensively investigated in recent years. In this work, we proposed an instrumented indentation method for soft materials based on a piezoelectric bimorph cantilever where the indentation force (F) is measured by a strain gauge and the indentation depth (h) is monitored by a piezoelectric motor driven displacement platform. The quasi-static mechanical properties of the soft samples are obtained by using the F-h curve and the dynamic properties are extracted from the contact resonance curve of the piezoelectric cantilever which is measured by using electromechanical impedance (EMI). Firstly, the working principle of this indentation method for quasi-static and dynamic mechanical property measurement is presented. Then, both the quasi-static and dynamic indentation testing were conducted on a silica gel sample, and the testing results fit well with that obtained using tensile testing. Later, the viscoelastic properties of a Polydimethylsiloxane (PDMS) sample was tested which is strongly dependent on the indentation force. Finally, modulus imaging was conducted on a silica gel sample containing a stiffer elastomer sphere using the local contact stiffness (LCS) as the indicator, and the elastomer can be clearly revealed. The proposed piezoelectric cantilever based instrumented indentation method is very convenient for mechanical characterization of soft materials and may be widely used in near future.

Моделювання впливу параметрів збурень на роботу двоканального п’єзоелектричного гравіметра

The work is devoted to the problem solving of study of the influence of both perturbing accelerations parameters and the inherent parameters of a dual-channel piezoelectric gravimeter on its operation, by means of a computer. For this purpose, a mathematical model of a dual-channel piezoelectric gravimeter was used. In consequence of the carried out mathematical model modeling, the results of modeling on a computer are obtained and presented. The influence of the external disturbance parameters on a new dual-channel piezoelectric gravimeter operation was modeled. As external disturbances, the following was considered: influence of both frequencies and amplitudes of forced vibrations of the base (along longitudinal and transverse axes), on which a dual-channel piezoelectric gravimeter is located, as well as the disturbing vibration accelerations for the most unfavorable resonance cases: w = w0, w = 2w0, w = 3w0, 2w = w0, 3w = w0, where w0 — is the natural vibration frequency of a dual-channel piezoelectric gravimeter, w - is the disturbances frequency. In consequence of the carried-out modeling, the graphs of the output signal change were obtained for various values of the disturbance frequency of vibration accelerations, the damping coefficient and various values of the disturbing vibration accelerations amplitudes. In view of each result and graph that have obtained, the analyzes as to the steady-state forced vibrations magnitude of a two-channel piezoelectric gravimeter as well as the conclusion concerning presence or absence of resonance were made. Using the results of previous studies of the authors, the comparison of the analytical solution of the equations of a dual-channel piezoelectric gravimeter motion, when exposed to the external disturbances was carried out with the results of digital modeling. The analysis of the modeling results has shown that the mean root square deviation of the solutions does not exceed 0.009 mm and this analysis has confirmed the adequacy of the mathematical model of a two-channel piezoelectric gravimeter, in other words, the obtained mathematical model of a dual-channel piezoelectric gravimeter corresponds to a real device and this model can be used for further studies of a dual-channel piezoelectric gravimeter motion parameters.

Construction of an intravascular ultrasound catheter with a micropiezoelectric motor internally installed.

Intravascular ultrasound (IVUS) has become a useful tool in the detection of coronary artery disease. However, non-uniform rotation distortion (NURD) reduces the image quality. In order to suppress the influence of NURD, a piezoelectric motor that can meet the requirements of IVUS catheters has been proposed. The motor has a diameter of 1mm and a length of 10mm using the new polarization direction proposed in the paper. A 45° mirror is fixed on the top of the motor to reflect the ultrasound transmitted from the transducer. The manufacture and drive of the piezoelectric motor is simple, and the maximum speed of the piezoelectric motor can reach 6450 rpm under the voltage of 20Vp-p. The minimum power required by the rotating motor is only 0.038W, which can be directly driven by the signal generator without a power amplifier. The motor can operate at a low voltage and still has a high and stable speed. Meanwhile, the speed of the motor is controllable and has a satisfactory stability with a maximum angular error of 8°. The images detected by the cooperation of the motor and the ultrasonic transducer are also shown, which indicates that the motor has the rotational stability that meets the imaging requirements and the potential for application in the IVUS catheter to help improve the image quality of the coronary arteries and prevent and help treat potential diseases.

Resonant-type piezoelectric inertial drive mechanism with asymmetric inertial masses.

Resonant-type piezoelectric impact motors can improve the output capability effectively. A new construction of asymmetric inertial masses is proposed to synthesize approximate saw-tooth wave resonant vibration with matched anti-phase and in-phase modes. A prototype is designed, manufactured, and tested. With 40Vp-p, 400Hz exciting voltage for the anti-phase mode and 16Vp-p, 800Hz exciting voltage for the in-phase mode, the prototype provides a maximum no-load velocity of 17.2 mm/s and a maximum output power of 0.72 mW with 100mN load. The velocity and output power of the prototype in the proposed resonant state are near three orders of magnitude higher than those in the traditional quasi-static state.

Gait Phase Recognition Using Fuzzy Logic Regulation with Multisensor Data Fusion

The health challenges brought by aging population and chronic noncommunicable diseases are increasingly severe. Scientific physical exercise is of great significance to prevent the occurrence of chronic diseases and subhealth intervention and promote health. However, improper or excessive exercise can cause injury. Research shows that the sports injury rate of people who often exercise is as high as 85%. Aiming at the problem of low accuracy of single sensor gait analysis, a real‐time gait detection algorithm based on piezoelectric film and motion sensor is proposed. On this basis, a gait phase recognition method based on fuzzy logic is proposed, which enhances the ability of gait space‐time measurement. Experimental results show that the proposed gait modeling method based on ground reaction force (GRF) signal can effectively recognize and quantify various gait patterns. At the same time, the introduction of heterogeneous sensor data fusion technology can effectively make up for the accuracy defects of single sensor measurement and improve the estimation accuracy of gait space‐time measurement.

Smart materials for changing the electrical properties of nanostructures

Smart materials have an important role in modern applications. They have contributed to improving various applications in several fields. One of the areas most affected by the improvement of smart materials is nanostructures. These materials are created by basic techniques, such as arrangement manipulation. Significant efforts have been made to enhance smart materials so that they resemble natural materials in terms of accuracy, design, and utility. Here, a review of the latest research on smart materials that can alter the electrical properties of nanostructures is presented. The main objective of this review is to introduce the role of smart materials in controlling the electrical performance of nanostructures. Furthermore, this review proposes an analysis of the integration and cooperation of previous research, such as the use of a piezoelectric motor in the design of structural magnetic nanodevices to control these devices. Piezoelectric actuators can also be used to develop a new method for controlling PV modulators for fabricating a single-wall nanotube. This new proposal could alter the properties of many nanoscale systems serving several medical and engineering fields. Moreover, this review proposes a novel methodology for nanocoating by introducing an antireflective coating with multiple layers. This method can effectively enhance the functions of the nanoscale coating.

Design Evolution of the Ultrasonic Piezoelectric Motor Using Three Rotating Mode Actuators

The development process and experimental investigation of the multicell piezoelectric motor is presented in this paper. The proposed design consists of three individual cells integrated into the stator, double rotor, and a preload system. Those elements are combined into a symmetrical structure of the motor. The two new prototypes have been designed, simulated and tested. Finite element numerical analysis is carried out to obtain optimal dimensions of the individual cell in terms of generated vibrations and resonant frequencies of the structure. The results of the numerical analysis are compared with analytical calculations based on the equivalent circuit model. The stator of the motor was manufactured using a three-dimensional (3-D) printer using alumide material. Finally, the experimental tests were conducted and presented. Analytical, numerical and experimental results are in satisfactory agreement. Two new prototypes of the multicell piezoelectric motor exhibit torque-speed characteristics similar to the original while being cheaper and easier to manufacture.

3D printing and dynamic modeling of a polymer-based bimodal piezoelectric motor

Owing to characteristics of single-step fabrication and rapid prototyping, 3D printing have potential applications in processing piezoelectric motors with complex structures. In this paper, a 3D printed resin-based bimodal piezoelectric motor is proposed. Four slots of the motor are designed to reduce the influence of large damping caused by polymer’s viscoelastic and enhance mechanical properties. Considering the viscoelasticity and internal structure of the stator, a dynamic model based on the proposed motor is developed. Furthermore, parameters of these slots are optimized using the Taguchi method. Prototypes are fabricated and experimentally investigated. The results demonstrate that the first longitudinal mode and the second bending mode are 17 765 Hz and 18 006 Hz respectively, which are consistent with the analytical model results. Under the voltage of 300 Vpp, the maximum no-load speed and maximum driving load of the slotted motor are 200 r min−1 and 20 g with a speed of 6 r min−1, respectively. Compared with the motor without slots, the speed and load capacity are increased by 25% and 33%. Therefore, the motor with slots exhibits better mechanical output performance.

A Dumbbell Shaped Piezoelectric Motor Driven by the First-Order Torsional and the First-Order Flexural Vibrations

A piezoelectric motor driven by the first-order torsional and first-order flexural (T/F) vibrations is designed, fabricated, and tested in this study. The actuating force is generated by the torsional vibration of the dumbbell-shaped vibrator, while the elliptical motion shape is adjusted with the flexural vibration. The rotor, pressed onto the vibrator’s lateral surface, is frictionally driven with the vibrator. Here, the torsional vibration, the shear modes of piezoelectric ceramics, and the driving method may contribute to high torque and high output power. To test the feasibility of our proposal, first, a prototype of the T/F vibrator is built and its vibration properties are explored. As predicted, the torsional and flexural vibrations are excited on the vibrator. Then, the load characteristics of the piezoelectric motor are investigated. The maximal torque, the no-load rotation speed, and maximal output power are 4.3 Nm, 125 r/min, and 16.9 W, respectively. The results imply that using the first-order torsional and the first-order flexural vibrations is a feasible method to achieve high torque and high output power of piezoelectric motors.