Showing papers on "Piezoelectric motor published in 2021"

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

Abstract: 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.

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

Abstract: 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 1 mm and a length of 10 mm 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 0.038 W, 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.

Development of a two-dimensional piezoelectric traveling-wave generator

Abstract: In this article, we present a new method to control the direction of traveling waves in either an x-direction or y-direction on a two-dimensional square plate. The core structure was composed of a ...

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

Abstract: 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 $\pi $ /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 ${V}_{pp} = {300}$ 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.

Tunable-focus liquid lens actuated by a novel piezoelectric motor

Abstract: In this paper, a tunable-focus liquid lens driven by a novel piezoelectric motor is proposed for the adaptive application. Compressing the liquid chamber, the curvature of the lens can be changed b...

A disc-type high speed rotary ultrasonic motor with internal contact teeth

Abstract: 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.

A study on modeling of a piezoelectric motor

Abstract: n this paper, a study on modeling of a piezoelectric transducer type rotary traveling wave ultrasonic motor (USM) is presented. First a mathematical model and numerical simulation results are achieved. The model is based on the theory of piezoelectricity and physic theory. An experimental model is worked out and compared to the numerical model. The influence of the temperature on characteristics such as the rotational speed of the motor is considered. The speed of the USM is measured at temperature between 17°Cand 50°C. To develop suitable control strategies for the drive, a fuzzy model type Takagi-Sugeno is used. The unknown parameters of the output membership functions are determined by least square method. Experimental data are used to examine the validity of the fuzzy model. Comparison between experimental and calculated data of the fuzzy model indicates that the fuzzy model can well describe the nonlinear characteristics among the frequency of driving voltage and rotating speed.

Mass transfer from the rotor to the stator for improving the speed of the piezoelectric motor based on centrifugal force

Abstract: To improve the speed of a piezoelectric motor based on centrifugal force, a method is proposed on the basis of mass transfer from the rotor to the stator. Multi-degree-of-freedom vibration models are established before and after mass transfer. A mass of 150 g is transferred from the six-hole rotor to the stator. This process increases the rotation frequency of the rotor under the same friction loss and increases the energy fed into the rotor by the stator. The motor operates at a frequency close to the resonance frequency. The change in the initial phase with the operating frequency close to the resonance frequency is analyzed, and the phase adjustment device and the signal processing circuit are designed. Two prototypes, one with and one without mass transfer, are fabricated and measured. As the initial phase is adjusted from 0° to 75°, the motor rotation frequency gradually increases, approaching the resonant frequency of the motor. When the excitation voltage is 790 Vp-p, the speed of the piezoelectric motor with a mass transfer of 150 g reaches 11 004 rpm, which is 89% faster than the speed of that without mass transfer.

Torque for non-contact piezoelectric motor modulated by electromagnetic force

Abstract: In this paper, the structural design and driving mechanism of a non-contact piezoelectric motor modulated by electromagnetic force are introduced. The equations of the electromagnetic force and torque of the electromagnetic modulation mechanism for the motor are deduced. Based on the piezoelectric constitutive equation and torque balance equations of the driving system, the equation of the piezoelectric driving torque is also obtained. Using these equations, the influences of the related parameters on the relationship between electromagnetic torque and angle difference between pole and rotor are studied. The influences of the main parameters and signal frequency on piezoelectric driving torques are analyzed. Based on them, the torque optimization of the motor is completed and the load-carrying ability of the motor is increased by about 50 times. A prototype of the motor is developed. Its output torque is tested and compared with calculated one which illustrates the theoretical model here.

An Aperture Driven By Single-Phase Piezoelectric Motor

Abstract: In this paper, a tunable aperture driven by a single-phase piezoelectric motor is presented. The piezoelectric motor is composed of piezoelectric ceramic and carbon fiber layer. The influence of fiber orientation on the mechanical characteristics of the motor is analyzed by finite element method. The prototype of the aperture is manufactured and tested. The results show that the opening and closing durations of the aperture are 89 ms and 92.4 ms, respectively, for a rotation range of 90°, under a driving voltage of 150V. The minimum angular resolution can reach $4^{*}$10-5 radian.

A Novel Design of Rotated Piezoelectric Actuators based on Impact Driving Principle

Abstract: The design of rotating piezoelectric actuators is mainly based on the guide shaft structure, and it requires a high accuracy of the output shaft and shaft hole. The working performance and application range of the rotating inertial piezoelectric motor are limited, thus a rotating inertial piezoelectric motor without a guide shaft structure was designed. The actuator can achieve unidirectional rotation movement by the whirling of the inertial mass to produce asymmetrical inertial impact force when the piezoelectric bimorph pasted on the substrate was applied to the asymmetric electrical signal. The dynamic model of the rotated actuator is constructed, and the working principle of the newly designed rotating inertial piezoelectric motor is analyzed and verified by simulation. A piezoelectric experimental system was conducted and frequency characteristic, step length characteristic was tested. The results show that the step size resolution of the rotating inertial piezoelectric motor is 0.64μrad at 100V and 250Hz.

Preliminary Characterization of a Plastic Piezoelectric Motor Stator Using High-Speed Digital Holographic Interferometry

Abstract: Precise surgical procedures such as deep brain tumor ablation may benefit from intra-operative image guidance using magnetic resonance imaging (MRI). However, the MRI’s strong magnetic fields and constrained space pose the need for robotic devices to assist the surgeon. Piezoelectric motors are often used to actuate these robots. The piezoelectric resonant motor (PRM) is a class of such motors that consist of a bonded piezoelectric ring stator and a frictionally coupled rotor. Steady-state excitation at certain frequencies leads to specific mode shapes on the stator with surface waves having both in-plane and out-of-plane displacement components that cause the coupled rotor to spin. High-speed digital holography (HDH) can be used to measure time variant displacements with nanometer and microsecond resolution. We present initial measurements acquired at 67 k frame per second (fps) of two custom-designed plastic stator components operating at drive frequencies of 6.788 kHz and 6.980 kHz, respectively. Circumferential motion of the traveling surface waves with out-of-plane peak-to-peak displacement of approximately 100 nm peak-to-peak amplitude and a settling time of 2.99 ms was observed. Results demonstrate that plastic stators may be a promising alternative to metallic stators for use in the MRI environment.

Development of Dual-Friction Drive Based Piezoelectric Surface Acoustic Wave Actuator

Abstract: This chapter deals with the modeling and simulation of a dual friction-drive (DFD) piezoelectric motor driven by a Rayleigh surface acoustic wave. Different techniques of modeling of SAW devices are discussed along with finite element simulation of resonator and delay line. The proposed SAW motor involves a cubical shaped object called slider which is kept tightly between two piezoelectric stators preferably identical in nature. The stator is typically made of lithium niobate facing each other, while each stator having an IDT placed on both ends. A Rayleigh SAWs is generated on the surfaces of both stators when sinusoidal excitations applied to the pair of IDTs on one side and the wave interacts with the slider. A sufficient amount of preload is applied externally; the generated SAWs generate frictional forces on the two surfaces contacting the slider and makes a translational motion to the slider. The reverse direction of motion of the slider can be performed by changing the excitation conditions to the pair of IDTs on the opposite side. The chapter describes the modeling of IDTs including characteristics, principles, and generation of surface waves, and finally, through finite element simulation, it discusses the operation of SAW motor along with displacement of the slider, contact pressure, and forces acting on the slider.

Double-folding cross multi-dimensional piezoelectric motor, control method thereof and scanning probe microscope

Abstract: The double-folding cross two-dimensional piezoelectric motor comprises a sliding plate, an XY piezoelectric body frame and X +, X, Y + and Ypiezoelectric bodies, the two ends of the XY piezoelectric body frame in the X direction and the Y direction are called the X + end and the X end and the Y + end respectively, one end of each X + piezoelectric body is fixed to the X end, and the other end of each X + piezoelectric body is a free end and points to the X end; the X + piezoelectric body and the X piezoelectric body form a double-layer folding X piezoelectric body up and down; the Y + piezoelectric body and the Y piezoelectric body are fixed on the XY piezoelectric body frame in a similar mode to form a double-layer folding Y piezoelectric body; the double-layer folding X piezoelectric body and the double-layer folding Y piezoelectric body are in a cross overlapping shape and form a cross XY piezoelectric body together with the XY piezoelectric body frame, and the free ends of the fourpiezoelectric bodies are pressed on the sliding plate through force equal in magnitude. The invention also relates to a three-dimensional piezoelectric motor and a scanning probe microscope which aremade of the piezoelectric material. The piezoelectric actuator has the advantages of being high in piezoelectric body utilization rate, large in thrust, small in size, self-adjustable in elasticity,wide in stroke and large in working temperature zone.

Design and Characterization of a Planar Motor Drive Platform Based on Piezoelectric Hemispherical Shell Resonators

Abstract: In this study, a planar ultrasonic motor platform is presented that uses three half-side excited piezoelectric hemispherical shell resonators. To understand the working principle and the harmonic vibration behavior of the piezoelectric resonator, the trajectory of the friction contact was measured in free-oscillating mode at varying excitation frequencies and voltages. The driving performance of the platform was characterized with transport loads up to 5 kg that also serve as an influencing downforce for the friction motor. The working range for various transport loads and electrical voltages up to 30 V is presented. Undesirable noise and parasitic oscillations occur above the detected excitation voltage ranges, depending on the downforce. Therefore, minimum and maximum values of the excitation voltage are reported, in which the propulsion force and the speed of the planar motor can be adjusted, and noiseless motion applies. The multidimensional driving capacity of the platform is demonstrated in two orthogonal axes and one rotary axis in open-loop driving mode, by measuring forces and velocities to confirm its suitability as a planar motor concept. The maximum measured propulsion force of the motor was 7 N with a transport load of 5 kg, and its maximum measured velocity was 77 mm/s with a transport load of 3 kg.

Non-metal Piezoelectric Motor Utilizing Langevin-Type Alumina/PZT Transducer Working in Orthogonal Bending Modes.

Abstract: To apply ultrasonic motors (USMs) to the chemical industry, in this study, alumina is employed as vibrating bodies of transducers as it offers not only high chemical resistance but also a possibility to generate high output torques and power of motors due to the high Young’s modulus. First, a Langevin-type transducer was constructed by clamping several annular lead-zirconate-titanate (PZT) disks between two rod-shaped alumina vibrating bodies, and a traveling wave was excited to drive the rotor by a superposition of two orthogonal standing waves in bending modes. Subsequently, the performance of the alumina/PZT motor was assessed and compared to those of the metal/PZT motors with identical structures when the same voltage was applied. As predicted, the alumina/PZT motor provides higher performance than the metal/PZT ones. Since the alumina/PZT transducer has relatively high strain in its PZT disks owing to the high Young’s modulus of alumina, it exhibits a relatively high force factor, leading to a high output torque of the alumina/PZT motor. In the meantime, the transducer stores higher vibration energy due to the larger force factor; this enables the alumina/PZT motor to exhibit a higher output power. Besides, a higher rotation speed is obtained with this motor because the alumina/PZT transducer has a larger vibration velocity on the end surface. These results indicate the high applicability of alumina to high-power USMs as their vibrating bodies.