Piezoelectric Motor Research Articles

Angular Stability Control System for Linear Pie-Zoelectric Motor

The paper is devoted to the system for measuring the stability of the angles Yaw (θz), Pitch (θy) and Roll (θx) of a linear piezoelectric motor type LPM5 / BSP-1540SL, which allowed to measure the angular deviations of the piezoelectric carriage depending on its position. The system was based on the use of the auto-collimation method, which provided the measurement of the angular discrepancy between its own optical axis of the auto-collimator and the normal to the plane of the mirror-reflecting surface. To measure the angular deviation of the carriage of the engine was used AK-0,5U auto-collimator with an optical resolution of 0.5 arc seconds. The auto-collimator scale was marked up in steps of 0.5 arcmin (30 arcsec), and its informative optical reference was made as a green intersection. This feature was later used to determine its position on the image obtained with the CCD matrix OV5647. The image obtained from the matrix had a resolution of 1024x768 pixels. In the matrix image, the distance between adjacent labels (auto-collimator scale step) was ~ 35 pixels, that is, the electronic resolution of the matrix was near to ~ 1 arc second. For control the engine speed and its position was used an optical encoder iC-PX3212 with a resolution of 2.6 µm. The control system also includes a single-board computer RaspberryPi 3B + , which allowed to control the engine via USB data protocol, receive images via MIPI-CSI protocol, process images from the array, and output it to the monitor via HDMI. During the experiment, 376 images were obtained (188 images when measuring Pitch, Yaw angles, and 188 images when measuring Roll angle). Image processing was performed using PIL (image) and numpy libraries in Python programming language. Was demonstrated the possibility of measuring angular stability over a large distance of movement with an accuracy of 5 arc.sec. On the basis of the experimental results obtained, it was found that most changed the angles of Pitch and Roll (~ 3 angular minutes). The results obtained by measuring the angles of Pitch, Yaw and Roll make it possible to develop a model of errors of a multi-axis micromanipulation system in order to take them into account when designing the control system.

Developing a Parallel Robot for MRI-Guided Breast Intervention

In MRI-guided breast intervention, the biopsy procedure is carried out by manually inserting a biopsy gun. However, some lesions are barely accessible with conventional tools, and the imaging process must be repeated multiple times for a better insertion coordinate. In this paper, we present a parallel robot for MRI-guided breast intervention. The robot employs a nonmagnetic, compact design, and has a unique three-link-four-rotational (3-4R) parallel mechanism that can insert the biopsy gun from various angles. The robot is remotely driven by a cable-actuated system and piezo-electric motors. It can be safely operated inside MRI bores with promising biopsy needle targeting accuracy. Comparative experiments are performed to validate the kinematics and to evaluate the performance on repetitive accuracy, structural stiffness, cable tension, and magnetic resonance. The experimental results show that the robot satisfies the operational requirements and can provide effective assistance in clinical breast biopsy.

A novel high performance integrated two-axis inchworm piezoelectric motor

In all of the actuating mechanisms for the precision positioning systems such as compliant, inertial, ultrasonic and inchworm, the lack of an integrated precision positioning system with high stroke and multi-axis operation is felt. In this paper, a state-of-the-art integrated two-axis inchworm piezomotor with an innovative operating principle is proposed. This piezomotor consists of two stages that are integrated, and each one delivers continuous motion in one-axis. Each of the stages consists of three actuating parts: two clamping actuators to engage/disengage with the guideway or frame (depend on the stage), and one feeder actuator to provide the step-by-step motion. The mode shapes and Von Mises stress distribution for each stage are analyzed by using the finite element analysis method. The performance of each stage is then verified throughout the experimental tests. The experimental tests are carried out to realize the two-axis piezomotor characteristics such as step pitch, resolution, axial speed, bearing capacity, and operating frequency in each stage.

Conceptual Design of Oblong Ring Vibrators

Abstract An oblong ring-type structure is composed by two straight segments (length L) and two semicircular segments (radius R). It can be used to generate traveling waves, being applied to build linear piezoelectric motors and linear conveyor systems. The traveling waves to such applications occur at specific frequencies, generated by simultaneous symmetric and antisymmetric flexural vibration modes which, in general, have distinct natural frequencies. However, for specific designs, they may coincide or be very close. This may be achieved by finding the appropriate L/R ratio. For preliminary design, an analytical model is very desirable, due to its computational efficiency and the absence of a computational automatic identification of symmetric and antisymmetric flexural vibration modes among numerical solutions. Therefore, the objective of this work is to propose an analytical and practical model to determine classes of vibration modes of interest for producing traveling waves in oblong ring-type structures, being employed for conceptual design such that the L/R ratio is determined in an efficient way. The oblong ring is considered as a beam-like structure composed by straight and curved segments, employing Timoshenko and Euler–Bernoulli kinematic assumptions. A design method is proposed by solving sequentially and systematically distinct geometric proposals of oblong ring-type designs and, for each one, evaluating the candidates to produce the flexural traveling waves. Later, the strong-candidates are analyzed by finite element models to test the quality of the design with less assumptions. We show that the methodology provides convenient results as a design method for oblong ring-type structures.

Piezoelectric Actuators and Motors: Materials, Designs, and Applications

AbstractPiezoelectric actuators are unique driving force‐generation devices, which can transfer input electric energy into force, displacement, or movement outputs efficiently and precisely via piezoelectric effect‐based electromechanical coupling instead of electromagnetic induction. In comparison with traditional electromagnetic actuators, the most important features of the piezoelectric actuators are their compact size, flexible design, and ability to provide nanometer or sub‐micrometer positioning. Here, recent progress in nonresonance piezoelectric actuators including multilayer ceramic actuators, step motors, inertial motors, and resonance ultrasonic motors, such as linear motors, rotary motors, multidegree of freedom motors, and microelectromechanical system actuators, is comprehensively presented. The working principles and properties of these actuators are explained, and the piezoelectric materials and configurations, fabrication, and applications are provided. Furthermore, from the aspects of materials, designs and applications, challenges and outlooks for future developments of piezoelectric actuators and motors are also discussed.

Design and Experiments of a Piezoelectric Motor Using Three Rotating Mode Actuators.

This paper represents a numerical and experimental investigation of the multicell piezoelectric motor. The proposed design consists of three individual cells that are integrated into the stator, double rotor, and a preload system combined into a symmetrical structure of the motor. Each of the cells is characterized by a traveling wave and rotating mode motor. A finite element numerical analysis is carried out to obtain optimal geometrical 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 theory. Experimental tests are also presented, including laser interferometry measurements of vibrations generated at the surface of the stator, impedance analysis, as well as measurements of mechanical characteristics of the complete motor. The final stage of the study concludes that the presented motor can provide relatively high torque compared with other traveling wave rotary motors.

Design and Analysis of a Piezoelectric Linear Motor Based on Rigid Clamping

Design and Analysis of a Piezoelectric Linear Motor Based on Rigid Clamping

Abbe error compensation for a micro/nano CMM with a coplanar stage

A micro/nano Coordinate Measuring Machine (CMM) with a stroke of 20 mm × 20 mm × 10 mm has been developed by our group. The “Pagoda structure” with Chinese style is adopted, which has fine mechanical stability. The base of the micro/nano CMM is made of granite to achieve high thermal stability. The stages are driven by piezoelectric motors with a resolution of 1 nm in three directions. The displacements of the stages in horizontal directions are detected by homemade Michelson interferometers. The optical axes of the two interferometers are consistent with their slide way of the coplanar stages respectively, which can reduce the Abbe errors in X and Y axes as much as possible. Semiconductor laser diodes are used as the light source of the interferometers due to low-cost and small size. A linear diffraction grating interferometer (LDGI) has also been developed to detect the displacement in Z direction. After subdivision, the measuring resolution can reach nanometer scale. The micro/nano CMM is compatible with different types of probes. A model of Abbe error and its compensation method are proposed in this paper. Experimental results show that the positioning errors were reduced from 435 nm to 91 nm and from 426 nm to 151 nm via Abbe error compensation method. The flatness of a 0-grade gauge block was tested by the micro/nano CMM, the repeatability of 44 nm (K=2) was achieved.

РОЗРОБКА П’ЄЗОДВИГУНА ДЛЯ БІОПРОТЕЗА

Currently, worldwide, the development and research of piezoelectric motors is a very relevant and important problem that attracts a large number of researchers. The interest in this problem is due to the prospect of creating small piezoelectric motors. This allows to obtain unique devices in which electric vibrations turn into rotary movement, in addition, the rotating moment that develops on the shaft of such an engine is so large that eliminates the need for a mechanical gearbox to increase the torque. The world leaders in the production of piezoelectric motors are the following companies: Physik Instrumente (PI), New Scale Technologies and others. The main purpose of this paper is to study and improve piezomotors, for the use in bioprostheses as actuators. Piezomotors are the main element of many microelectromechanical systems that are used in military sphere, in particular in robotics, and also in scientific research instruments. But all these piezoelectric motors have a number of disadvantages, the main of which are: high control voltage, small range of movement of the moving parts, the complexity of manufacturing structures, and large dimensions that reduce their application in various fields. Based on the drawbacks of these constructions, we have proposed and developed our own piezoelectric motor design, and simulated one biomorphic plate in the COMSOL Multiphysics program package. With the COMSOL Multiphysics program, forms of mechanical oscillations, deformations, resonance frequency of bending oscillations, and maximum amplitude of oscillations are determined. Also, in this paper, the coefficient of stiffness of bimorph piezoelements is given, thus, a qualitative mathematical model can significantly reduce the time and costs for the development of bimorph piezoelements. The use of bimorph piezoelectric cells in the developed piezoelectric motor increases the ampli-tude of oscillations, and reduces the amplitude of the control signal. The obtained data can be used in the design of devices where piezoceramic actuators are used.

Design of an H-shaped linear piezoelectric motor for safety and arming device

In this contribution, an H-shaped piezoelectric motor based safety and arming device that is driven by the hybrid of symmetrical first longitudinal mode and second bending mode is proposed, designed and experimental investigated. The proposed system operates based on the concept of self-moving and show potential infield of fuse system with different calibers. The actuating mechanism is that the four driving feet contact with the guides alternately and push the motor to move continuously. Modal and harmonic analysis are conducted to determine the dimension of the structure, confirm the working principle and analyze the motion trajectories of driving feet with finite element method. It is shown that trajectories of the driving feet are oblique ellipses with different angles because of the asymmetry of structure. In addition, a prototype is fabricated and experimented. The results show that the average speeds of the prototype in two directions are 120.6 mm/s and 130.1 mm/s respectively under the driving voltage of 120 V0-p and working frequency of 88.5 kHz. The H-shaped piezoelectric motor based safety and arming device can change its state from safety to arming or reversely in 25 ms with the fixed stroke of 3 mm.

Body-mounted robotic assistant for MRI-guided low back pain injection.

This paper presents the development of a body-mounted robotic assistant for magnetic resonance imaging (MRI)-guided low back pain injection. Our goal was to eliminate the radiation exposure of traditional X-ray guided procedures while enabling the exquisite image quality available under MRI. The robot is designed with a compact and lightweight profile that can be mounted directly on the patient's lower back via straps, thus minimizing the effect of patient motion by moving along with the patient. The robot was built with MR-conditional materials and actuated with piezoelectric motors so it can operate inside the MRI scanner bore during imaging and therefore streamline the clinical workflow by utilizing intraoperative MR images. The robot is designed with a four degrees of freedom parallel mechanism, stacking two identical Cartesian stages, to align the needle under intraoperative MRI-guidance. The system targeting accuracy was first evaluated in free space with an optical tracking system, and further assessed with a phantom study under live MRI-guidance. Qualitative imaging quality evaluation was performed on a human volunteer to assess the image quality degradation caused by the robotic assistant. Free space positioning accuracy study demonstrated that the mean error of the tip position to be [Formula: see text] mm and needle angle to be [Formula: see text]. MRI-guided phantom study indicated the mean errors of the target to be [Formula: see text] mm, entry point to be [Formula: see text] mm, and needle angle to be [Formula: see text]. Qualitative imaging quality evaluation validated that the image degradation caused by the robotic assistant in the lumbar spine anatomy is negligible. The study demonstrates that the proposed body-mounted robotic system is able to perform MRI-guided low back injection in a phantom study with sufficient accuracy and with minimal visible image degradation that should not affect the procedure.

Design and verification of a micro piezoelectric motor with energy harvesting characteristic for capsule endoscope

Wireless capsule endoscopy has the distinctive advantage of providing trustworthy results without substantial discomforts to patients. However, lack of capsule active motion control and energy supply have been significant obstacles preventing wider applications of this technology. To overcome these problems, this paper presents a micro piezoelectric motor with energy harvesting feature. The motor is driven by a single-phase voltage and can be used in capsule endoscopy. The stator was constructed by bonding two PZT plates (PZT1 and PZT2) onto the adjacent outer surfaces of a metal base. PZT1 and PZT2 can both be used to excite the in-plane bending modes of the stator to generate a traveling wave in the stator. The PZT plate supplied with no-exciting voltage source can be used to convert the superfluous vibration energy of stator body into electric energy to power small electronic devices. The elliptical trajectories of points on the stator surface result from a superposition of the two bending modes. The vibration and energy conversion characteristics of the stator were analyzed by using the finite element analysis software ANSYS. The structure parameters of the stator were adjusted until the mode mixture of the stator disappeared. A prototype motor was fabricated and tested to explore its mechanical and electric energy output abilities. The size of the prototype motor is about 9.8×9.2×22.0 mm3. The tested resonance frequencies of the operating modes are 15.305 kHz and 15.815 kHz, respectively. The maximum no-load speed is 85 rpm. The applied single-phase driving voltage is 100 Vo-p (peak voltage) at frequency of 15.54 kHz. The stall torque is 0.98 mN·m, and the maximum output power of the harvesting PZT plate is 127 mW under an optimal equivalent load resistance of 5.16 kΩ.

Design and research of a high speed small piezoelectric turntable

In order to achieve fast target locking and tracking in imaging system, a high-speed small piezoelectric turntable is designed. The piezoelectric turntable is driven directly by piezoelectric motor and has compact structure, which can realize high-speed rotation of imaging system. According to the index, the structure of piezoelectric turntable is designed, and the three-dimensional model is built by SolidWorks software. After simplifying the model, the finite element model is built by ANSYS software, and the static analysis of the turntable is carried out. Different materials were used to design the turntable, and their mass is compared. It is determined that the mass of the turntable with new materials is the lowest. The static analysis of the turntable with new materials shows that the designed turntable meets the design requirements of stiffness and strength, which provides a reference for the design optimization of similar turntables.

Design and characteristic analysis of a four-claw spherical photoelectric stabilization platform

Airborne photoelectric stabilization platform is an important tracking and scanning equipment. In order to make the photoelectric stabilization platform smaller and lighter, a four-claw spherical photoelectric stabilization platform is proposed. The four-claw spherical photoelectric stabilization platform is driven by piezoelectric motors with parallel structure. SolidWorks software is used to build the three-dimensional model of the stabilized platform. After reasonable simplification, the finite element model is built in ANSYS software. Comparing different mesh generation methods in the process of establishing finite element model, the mesh distortion is reduced from 0.74 to 0.38 by changing the mesh correlation and refinement. Different materials are used to design the platform, and the mass of the platform under different materials is compared. The platform mass of the new material is 30.3% and 66.4% less than that of the other two materials. The static characteristics of the platform with new materials are analyzed, and the maximum deformation and stress of the platform are analyzed. The results show that the designed airborne spherical photoelectric stabilized platform with new materials meets the requirements of stiffness and strength, which provides a reference for the design of such platform.

Research of concomitant shock-vibration noise of a piezoelectric motor in the mode of micro and nano speed

This work is devoted to improvement of methods for controlling the speed of piezoelectric motors in the micro and nano-bands. Based on the physical principles of the piezoelectric motor, taking into account the specifics of control signals and feedback, investigated the shock-vibration effects for linear piezoelectric motor by quasirezonance type under different speed control modes in the range of 0,1 μm/s...10 mm/s. Proposed speed control algorithms, which ensured a decrease of 2...10 times the shock-vibration effect in comparison with pulse-width modulation. It is established that in the speed microwave range the most effective are combined algorithms that combine as elements of continuous control by frequency response scanning for engine, and pulse – by internal modulation of excitation frequency. The paper shows that the most effective control in nano-band is frequency control with a fixed duration of control pulse – a nanocorrect engine. The obtained results allow to provide a control range of speed (5 orders) for linear piezoelectric motor taking into account it`s operating conditions in a micromanipulation system, as well as provide opportunities for use linear piezoelectric motors of quasi-resonance type in robotic and manipulation systems in micro and nano-range and further improvement in terms of miniaturization and increased accuracy.

Improvement on the Structure Design of a Kind of Linear Piezoelectric Motor with Flexible Drive-Foot

Linear piezoelectric motors have wide application prospects in precision instrument, biomedical engineering and many other high technology fields. In this paper, a linear piezoelectric motor operating in non-resonant state was proposed by using a flexible mechanism with characteristics of precision displacement output. Since the stator structural characteristic affects the stability and output performance of the motor directly, this paper focused on the improvement on the structure design of a motor stator with flexible five-bar drive-foot. Firstly, by analyzing the displacement output characteristics of flexible five-bar mechanism, the elliptical trajectory of drive-tip was investigated. Then the drive-foot was particularly designed with the characteristics of flexible structure, and its main structure parameters ware improved by the finite element method. Further, the integrated structure of stator was designed and fabricated. Finally, the comparison tests of the two motors were carried out. The experimental results show that the output force and efficiency of the improved piezoelectric motor are increased by 52.38% and 159.15%, respectively.

Piezoelectric Motor Utilizing an Alumina/PZT Transducer

To enhance the torque and output power of the rod-shaped piezoelectric rotary motors, in this article, we employ alumina to substitute the metal parts of the transducers considering that the high Young's modulus of alumina may avoid preload-induced vibration reduction and enable the transducers to generate the high driving force. Besides, alumina exhibits a relatively low density compared to most of the materials commonly used as the vibrating bodies (except aluminum alloy); this probably enhances the power densities of the piezoelectric motors. To assess the validity of our proposal, we constructed a Langevin-type alumina/lead–zirconate–titanate (PZT) motor and investigated its load characteristics. The transducer of 35 mm in outer diameter operated in orthogonal bending (B2) modes and drove the rotor with its end surface. The alumina/PZT motor yields the maximal torque and maximal output power of 1.56 N·m and 26.0 W, respectively, both of which exceed those of the metal/PZT motors having identical structure and working in B2 modes. Additionally, its power density reaches 56.3 W/kg, relatively high among the rod-shaped rotary motors although some of which work in more powerful modes. This article validates the effectiveness of our proposal and provides a new approach to improve the performance of the rod-shaped piezoelectric rotary motors.

Design and experiment of a slender nonresonant linear piezoelectric motor based on bridge-type amplification mechanism

A miniature non-resonance type linear piezoelectric motor based on a mechanical bridge-type amplification mechanism has been developed. The slender motor measures 29 mm × 5 mm × 3.5 mm. The stator consists of a parallel bridge amplifier and two multilayer piezoelectric actuators. The working principle of the motor is analyzed, and the physical performance of the bridge amplification mechanism is obtained by a finite element analysis. A prototype of the motor is manufactured, and the model is verified by experiment, and the mechanical properties of the motor characterized. The test results show that when the phase difference between the two driving signals is 90°, the output driving force of the motor reaches its maximum. The motor speed increases linearly from 2.2 mm/s to 7.6 mm/s when the driving frequency ranges from 100 Hz to 1100 Hz under the conditions of peak driving voltage 140 V, bias voltage 70 V and holding force 2.2 N. The motor speed decreases with the increase of load. When the driving frequency is 900 Hz and the holding force is 6 N, the maximum driving force can reach 1.41 N.

Tests of a Noncontact Piezoelectric Motor Modulated by an Electromagnetic Field.

For improving the service life of piezoelectric motors and the performance of noncontact piezoelectric motors, a novel noncontact piezoelectric motor modulated by the electromagnetic field is proposed. This type of piezoelectric motor uses an electromagnetic field to modulate the reciprocating vibrations of a piezoelectric drive mechanism to form the step motion of the rotor. The working principle and structural design of the piezoelectric motor are described in detail. A prototype motor is manufactured and the test system of output characteristics is established. An experiment of the output characteristics was carried out for exploring the driving scheme under different parameters of the drive signals. The results state that the proposed motor has a rotational speed of 0.038 rad/s, step angle of approximately 1°, output torque of 6 [Formula: see text]mm under the drive voltage of 150 V, frequency of 3 Hz, and modulation voltage of 7 V.

Design and fabrication of a new piezoelectric paper feeder actuator without mechanical parts

A piezoelectric paper feeder actuator using Micro Virtual Roller (MVR) is proposed, designed, fabricated and tested. This actuator can drive a sheet of paper forward or backward without any mechanical parts, such as the costly and heavy rollers used in traditional paper feeders. In this paper feeder actuator, two vibrating stators which produce traveling waves are used to drive the paper. The vibrations of the stators are similar to those of piezoelectric motors and follow a similar procedure to move the paper. A feasibility study simulated the actuator in COMSOL Multiphysics Software. Traveling wave and elliptical trajectories were obtained and the dimensions of the stator were optimized using FEM so that the paper could move at top speed. Next, the eigenfrequencies of the actuator was determined. Experimental testing was done in order to validate the FEM results that revealed the relationships between speed and parameters such as frequency and voltage. Advantages of this new mechanism are the sharp decrease in power consumption and low maintenance.