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A 2-DOF piezoelectric platform for cross-scale semiconductor inspection

To address the challenge of achieving extensive travel and high precision in semiconductor inspection, this study proposes a novel 2-DOF cross-scale piezoelectric positioning platform. In semiconductor inspection, the platform utilizes elliptical, stick-slip, and direct-push drive modes to meet the motion requirements at millimeter, micrometer, and nanometer scales. By applying defined electrical signals to the piezoelectric units, the platform can achieve high-speed continuous mode (HCM) for the millimeter scale, low-speed stepping mode (LSM) for the micrometer scale, and high-precision positioning mode (HPM) for the nanometer scale. Theoretical analysis and simulations were performed to design the flexible stator of the platform, and its dynamic characteristics were analyzed. A prototype was fabricated, assembled, and experimentally tested to investigate the mechanical performance of the proposed platform. The results show that the prototype successfully realizes cross-scale motion in the three modes: achieving a maximum no-load speed of 62.47 mm/s in HCM, a low-speed stepping motion of 14.62 μm/s in LSM, and high-precision positioning with a resolution of 25 nm within a range of ±21 μm in HPM. Through the flexible switching and cooperation of the three drive modes, the platform can quickly approach the target at millimeter speed, further approach with micrometer step motion, and finally achieve nanometer precision positioning. Finally, the positioning platform was successfully applied to inspect semiconductor devices for defect inspection. This study explores a novel cross-scale driving method for piezoelectric positioning platforms, which provides a new approach for precision manipulation research related to semiconductor component inspection.

Development of a Plate Linear Ultrasonic Motor Using the Power Flow Method.

Linear ultrasonic motors can output large thrust stably in a narrow space. In this paper, a plate linear ultrasonic motor is studied. Firstly, the configuration and operating principle of the Π-type linear ultrasonic motor is illustrated. Then, two slotting schemes are put forward for the stator to enlarge the amplitude of the driving foot and improve the output performance of motor. After that, a novel optimization method based on the power flow method is suggested to describe the energy flow of stator, so as to estimate the slotting schemes. Finally, the prototypes are manufactured and tested. The experimental results show that the output performance of both new motors are excellent. The maximum output thrust of the arc slotted motor is 76 N/94 N, and the corresponding maximum no-load speed is 283 mm/s/213 mm/s, while the maximum output thrust of V-slotted motor reaches 90 N/120 N, and the maximum no-load speed reaches 223 mm/s/368 mm/s.

Development of a comprehensive car safety gears testing procedure for low- to medium-speed lifts in Hong Kong

Operation of the safety gears is the last means of protecting passengers in a high-speed or even freely falling lift car. EN81-20 stipulates that the average retardation when the safety gears are engaged should lie between 0.2 g n and 1.0 g n while g n is the gravitational acceleration. Decades ago, in Hong Kong, to conduct a formal test on the safety gears, the car was fully loaded and the machine brake was manually released to allow the car fall freely until the overspeed governor triggered the engagement of the safety gears. This test was rather vigorous to both the gear jaws and the guiderails. Recently, tests have been conducted with 125% in-car load while the car travels under an inspection (or levelling) speed and the governor is manually triggered. Such a revised test, though much less vigorous, may not be able to verify the average retardation as required. Even a test with full load and free-falling may not reveal the whole truth by merely measuring the resulting contact scratches on the guiderails because a majority of the retardation could have been assisted by the counterweight via the suspension ropes. A method that involves an empty car traveling downward at 1 m/s with the governor manually triggered was first developed in Germany. This method has been improved to form a comprehensive procedure as detailed in this article so that a no-load rated speed, or slightly reduced speed, test is conducted, which is almost non-invasive or much less vigorous. By calculation, the average retardation when all suspension ropes are broken can be estimated. Cross-checking in our experiments revealed the validity of this procedure. The procedure also involves a test to verify the validity of parameters used to perform the estimation and takes care of some modern overspeed governors which cannot be manually triggered. It is hoped that this procedure could encourage maintenance professionals carry out safety gears tests more often to ensure a high safety standard. This comprehensive procedure could encourage more frequent tests on the car safety gears, which is almost non-invasive for manually triggerable overspeed governors or less vigorous for non-triggerable ones. An empty car traveling downward at rated speed, or at slightly reduced speed, is tested by manually triggering the governor while a partially loaded free-falling car is tested if the governor is not manually triggerable. Results can be used to estimate the average retardation of the lift car when all suspension ropes are broken. A pre-test is included to validate critical parameters necessary for the estimation. Experiments conducted so far were on the safety gears of low- to medium-speed lifts. For high-speed lifts beyond 4 m/s, that may be considered in the next stage of research. Although the title of this article includes the city where the procedure was developed, there is no reason why this testing procedure could not be extensively applicable to any traction lift systems around the world at such speed levels.

Modal analysis and output characteristics of an ultrasonic motor with a square prismatic shell stator

Abstract A rotary traveling wave ultrasonic motor having a square prismatic shell stator is proposed. The stator contacts with the rotor through interference fit, and elastically deforms slightly, and then presses against the rotor. Then the pre-pressure is created by the initial deformation of the stator with simple structure. The in-plane modal problem of the stator is analyzed by numerical method as a folded beam and the results are compared with those from finite element method (FEM) and laser doppler measurement. The 3rd and 5th degenerate modes with repeat natural frequencies are selected as working modes, and the influence of actuating frequency and voltage on the no-load speed and stall torque is studied by multi-physics simulation for the operation of these two modes. A prototype is fabricated and the output characteristics were tested and compared with the simulated results. The 3rd working mode is found to have better performance and can reach a no-load speed of 205 rpm and maximum torque of 3.9 mN·m when the input is 28.0 kHz and 100V. The effect of the pre-pressure for the 3rd working mode is discussed further.

A novel rotary ultrasonic motor based on multiple Langevin transducers: design, simulation, and experimental investigation

Traveling wave rotary ultrasonic motors (TRUSMs) have been applied in optical systems, robotics, biomedical and other fields. However, the disadvantages such as short working life, driving performance degradation, and low energy utilization significantly limit the long-term and stable operation of TRUSMs in advanced fields like aerospace mechanisms. To address the above issues, a novel rotary ultrasonic motor based on multiple Langevin transducers is proposed in this paper. First, the structural design, driving principle and general design criteria are described in detail. Then, the structural parameters are optimized by finite element simulation analysis. Second, a prototype is assembled controllably. Subsequently, the impedance test and vibration measurement are carried out. The results show that the traveling wave is successfully generated on the tooth-ring, and all the Langevin transducers are excited to the first-order longitudinal vibration modes, which strongly verify the correctness of design principle. Finally, the driving performance experiment is carried out. The experimental results show that the no-load speed is 62 r min−1 under the pre-pressure of 10 N. The stalling torque is 0.94 N m at the driving voltage of 500 Vp-p. The response characteristics show that the start/stop time are 4.6/5.5 ms, and the angular displacement resolution of clockwise/counterclockwise driving are 6.7/10.2 μrad. The motor proposed in this paper not only exhibits relatively high output performance with excellent vibration characteristics, but also maintains compactness of the structure. The sandwiched structure design effectively avoids the problem that the bonded-type piezoceramic rings in conventional TRUSMs are prone to damage or fall-off when vibrating for a long time. Furthermore, the general design criteria provide a new approach to develop high performance rotary ultrasonic motors. The proposed novel ultrasonic motor is expected to meet the demand for long-term and stable operation in aerospace mechanisms.

A miniature swimmer actuated by a PZT ring ultrasonic underwater propulsion system

This study investigates a scheme utilizing a ring transducer for an acoustic underwater propulsion system. Acoustic underwater propulsion systems are well suited for the inspection and repair of underwater robots due to their small size, high power density, and simple structure. Previous research has focused on self-propelled swimmers utilizing disc transducers. However, the radial vibration component of disc transducers makes it difficult to provide propulsion for an acoustic underwater propulsion system driven by an acoustic driving force. Pure longitudinal vibration requires a greater thickness to achieve the same vibration area, resulting in higher impedance and reduced driving efficiency. In this paper, simulation, and measurements of vibration distribution demonstrate that a ring transducer exhibits a vibration distribution closely resembling pure longitudinal vibration. A prototype swimmer using a ring transducer was fabricated for experimental evaluation through measurements of admittance characteristics, zero-speed propulsion, and no-load speed in water.

Model and Property Analysis for a Ball-Hinged Three-Degree-of-Freedom Piezoelectric Spherical Motor.

Multi-degree-of-freedom piezoelectric motors have the advantages of high torque and resolution, simple structure, and direct drive, which are widely used in robot wrist joints, deep-sea mechanisms, medical equipment, and space mechanisms. To solve the problems of high force/torque coupling degree and ball low stator and rotor bonding strength of the traditional traveling wave type three-degree-of-freedom piezoelectric spherical motor, a new structure of ball-hinged piezoelectric spherical motor is proposed. Through coordinate transformation and force analysis, the driven mathematical model of the spherical motor is given. The model shows that the three degrees of freedom of the motor are coupled with each other. According to the mathematical model of the spherical motor, the mechanical properties of the motor are analyzed by the computer simulation. The results show that the stalling torque coefficient kt has a linear relationship with the friction coefficient ε and the stator preload Fc, has a nonlinear relationship with the stator radius R and the rotor radius r, and increases with the increase of R and decreases with the increase of r. The no-load speed of motor ωn is not related to the friction coefficient ε and the stator preload Fc, and increases with the increase of R and decreases with the increase of r. The anisotropic characteristics of torque and speed of a spherical motor are further analyzed, which lays a theoretical foundation for the drive control of a spherical motor.

Numerical Investigation of the Influence of Cavitation on the Runner Speed at Speed-No-Load and Runaway for a Francis Turbine of Low Specific Speed

Abstract Studies have shown that the runner speed of hydraulic turbines at no-load conditions is affected by cavitation. However, those studies did not provide explanations relating the variation of the no-load runner speed to cavitation. Understanding why cavitation affects the runner speed is crucial because the maximum runner speed is reached in no-load condition, and this speed must remain below a limit to ensure the generator's safety. This paper uses numerical simulations to investigate the effect of cavitation on two no-load conditions, the runaway and the speed-no-load, for a low specific speed Francis turbine at model scale. The study is based on unsteady Reynolds-averaged Navier–Stokes simulations with and without cavitation and focuses on averaged quantities. At no-load, the regions over the blades producing a motor torque, i.e., oriented with the turbine rotating direction, must be balanced by regions producing a braking torque, opposed to the turbine rotation, to achieve a zero-torque condition. At runaway, cavitation mainly affects regions where a motor torque is produced. However, the zones affected by cavitation have a small contribution to the total motor torque. Therefore, for the runaway condition studied, the torque balance over the blade is hardly affected by cavitation, and the impact of cavitation on the runaway speed is negligible. At speed-no-load, comparisons between cavitating and noncavitating simulations indicated that cavitation affects mainly the braking torque regions. Those regions result from an interaction between the runner blades and a backflow extending from the draft tube cone to the runner outlet. In that case, cavitation strongly affects the torque balance over the blades, and consequently, the runner speed will adapt to find another zero torque condition.

Research on the bidirectional motion of resonant single-wing bionic piezoelectric motor based on a biasing self-clamping mechanism.

Based on our previous research, this article adds new research content and further refines the previous research on bionic motors. It is in the form of note as a complementary improvement to the previous article. This article proposes a novel approach to achieving reversal motion in such motors driven by a single harmonic signal, specifically the multimode mode of the vibrator. In contrast to the conventional inertial impact piezoelectric motor, we propose a bidirectional piezoelectric motor that can achieve bidirectional motion only by altering the driving signal characteristics. Compared to other bidirectional piezoelectric motors, this motor features a simpler structure and more convenient control. The COMSOL6.0 finite element analysis software was utilized to optimize the working mode of the piezoelectric motor, and an experimental platform was constructed for testing and verifying the performance of the designed prototype. The final experimental data demonstrate that, with an excitation voltage of 300Vp-p, a preload of 2 N, and an excitation frequency of 781Hz, the motor prototype achieves a maximum no-load speed of 12.15 mm/s, a maximum resolution of 15.27μm, and a maximum load of 14g. These results confirm the validity of the new working mode.

A novel miniature swimmer propelled by 36° Y-cut lithium niobate acoustic propulsion system

Self-propelled swimmers using ultrasonic transducers have been proposed and studied. The screw and bionic propulsion systems have dominated underwater robots. However, the complex structures make miniaturization difficult. The swimmers with ultrasonic transducers have no moving parts such as fins or propellers and can be driven by the nanomechanical-vibration in the surface of the transducer. Simple structure and high driving frequency make it easy to miniaturize. A 36° Y-cut lithium niobate (LN) thickness-vibration-mode transducer is used to investigate an underwater acoustic propulsion system. LN transducers are manufactured to 10 × 10 mm, 7 × 7 mm, and 4 × 4 mm square plates. The zero-speed propulsion and no-load speed are investigated to evaluate the swimmer performance. A mm-order swimmer is studied with a 4 × 4 mm LN transducer. At last, the multi-degrees-of-freedom swimmer driven by three 7 × 7 mm LN transducers is demonstrated with the advance and sway locomotion. In the future, a small-scale and agile self-propelled swimmer with an acoustic propulsion system can be expected for narrow and complex environment tasks, such as seagrass-prone areas and narrow pipelines.

Development of a novel single-mode miniature standing wave ultrasonic motor

A novel single-mode miniature standing wave ultrasonic motor (SUSM) is proposed. The SUSM uses the first extension vibration mode and second extension vibration mode of the stator to generate different diagonal vibration trajectories and drive the rotor to rotate in different directions through a single-phase signal. The bidirectional motion of the SUSM can be realised by switching the two vibration modes and excitation methods. The motor is designed and the operating principle is analysed. The resonant frequencies of the two vibration modes are determined by the finite element simulated analysis, and the transient analysis is adopted to obtain the diagonal trajectories of the driving part. Finally, a prototype of the single-mode SUSM is developed and the mechanical performance of the prototype is measured and evaluated. According to the experimental results, the motor has a no-load speed of 265.37 rpm (B1 mode) and 320.20 rpm (B2 mode) in each direction under 200 Vp−p and 100 Vp−p voltage excitation, and the maximum load is 60 mN and 70 mN, respectively.

Identification of Transfer Function to Model Brush Temperature of a Small DC Machine at No-Load

Using temperature measurement to provide insight into the health condition of an electrical machine at any operating point could be possible if a baseline temperature of the machine could be modelled in real-time and compared to the actual current temperature. In this study, transfer functions are being identified to be used as a baseline temperature response model for a small DC machine. As a preliminary study, the transfer functions are identified using experimental data of temperature responses at several no-load speed step inputs. The order of transfer function tested was between a range from 0 to 4. The third order transfer function was found to be the best followed by the first order transfer function with a model MSE error of less than 0.41 and 0.65 respectively. The slight variation on the poles of the system indicates that the thermal system of the electrical machine does not obey exactly the LTI hypothesis.

Design and experiment of a double-sided staggered conical teeth traveling wave ultrasonic motor

This paper proposed a double-sided staggered conical teeth traveling wave rotating ultrasonic motor based on in-plane bending mode, which reduces the difficulty of rotor preload application and improves the output characteristics of in-plane bending mode traveling wave rotating ultrasonic motor. The motor has four sets of drive teeth alternately distributed on both the inner and outer sides of the vibrator, with the drive teeth gap dedicated to accommodate the piezoelectric ceramic piece, and the staggered drive teeth on both sides of the vibrator are used to drive the rotor rotation. The motor operates in two in-plane third-order bending modes with the same frequency and orthogonal to each other, and is excited by four sets of piezoelectric ceramic disks spaced 90 degrees apart from the inner and outer sides. After the prototype was completed, its vibration characteristics and output performance were experimentally tested, and the actual effects of the three excitation schemes were compared. The experimental results show that the motor can provide a maximum output torque of 1.82 N·mm and a maximum no-load speed of 96.4 rpm when the excitation voltage is 300 V and the excitation frequency is 20.60 kHz.

Research on interactions between different operating modes of piezoelectric motors

This paper explores interactions between multiple operating modes of piezoelectric motors. The developed motor can operate in the second-order in-plane bending modes (I), the third-order in-plane bending modes (II) and the first-order out-of-plane bending modes (III). These working modes excited separately and simultaneously, can be manipulated electronically. Each of the vibrational modes can both be driven by applying single-phase and two-phase voltages to piezoelectric ceramic plates. In order to produce all the vibration states, the structural parameters of stator were strictly designed to harmonize two eigenfrequencies of each type of vibrational modes by using finite element software ANSYS. Displacement characteristics of stator driving particles under all vibration states were calculated to evaluate mutual effects of different operating modes. Simulation results reveal that the superposition of I and II corresponds to a mode with lower resonance frequency and larger vibration amplitude in stator body. For the designed motor, the conjunction of modes I and II actually forms the first-order in-plane vibrational mode B01. Therefore, the response displacement of stator driving points reaches the maximum value when modes I and II are conjointly actuated by supplying single-phase excitation voltage under the premise of undistorted three-dimensional motion trajectory. The motor performances under that condition were also investigated experimentally. The dimension of the fabricated prototype motor is 10 mm × 10 mm × 20 mm. The stall torque is 0.2 N·m under 200 V single-phase excitation, when the motor operates in modes I and II simultaneously. The maximum no-load speed is 74 r min−1. Compared with separate actuation of vibrational modes I and II, mechanical properties of the prototype motor are significantly improved.

A Double-Sided Tapered Teeth Traveling Wave Ultrasonic Motor Based on In-Plane Bending Mode

In order to improve the output torque of an in-plane bending mode traveling wave rotary ultrasonic motor, a double-sided tapered teeth traveling wave rotary ultrasonic motor was proposed. The motor is designed with three types of adaptive rotors that can be used for replacement in different output environments. Simulation analysis was conducted using ANSYS, and prototype production and experimental testing were conducted. The experimental results show that when the excitation voltage is 300 V and the excitation frequency is 22.665 kHz, the maximum output torque that the motor provide is 3.087 N·mm, and the maximum no-load speed is 295 rpm.

A wind-solar energy harvester based on airflow enhancement mechanism for rail-side devices

A significant challenge arising from the rugged climate and environment is the provision of power to isolated railway-side equipment on the Plateau. Emerging renewable energy harvesting technologies present a promising solution. This paper proposes and confirms a Wind-Solar Energy Harvester (WSEH) founded on an Airflow Enhancement Mechanism (AFEM) for powering rail-side equipment. The proposed WSEH comprises of Vertical Axis Wind Turbine (VAWT), Flexible Photovoltaic Deflectors (FPVDs), and energy conversion and storage devices. The AFEM is executed founded on the FPVD that amplifies the airflow energy blown towards the VAWT due to the Blockage effect. The FPVD, grounded on an umbrella-like mechanism, unfolds as a PV panel for solar energy collection; and folds as a deflector to raise the wind energy collection potential for the VAWT. Through CFD simulation, the VAWT’s maximum power coefficient attains 0.387, and the optimum gain effect of FPVD is 66.54%. The prototypes, comprising VAWT and FPVDs, are scrutinized in a wind tunnel to authenticate the practicable effects illustrated by the no-load speed and load output of VAWT. The case study demonstrates that the WSEH creates 1566.82 kWh of electrical energy per year, sufficient for powering rail-side equipment on the Plateau.

Development of a 3-DOF Cylindrical Ultrasonic Motor Based on Non-Standard Modes

Cylindrical multi-degree-of-freedom (multi-DOF) ultrasonic motors have the potential to significantly reduce motor size compared to other ultrasonic motors. They find applications in various systems, including micro-robot joints and space probes. This paper proposes a 3-DOF cylindrical ultrasonic motor with hybrid vibration modes. Hybrid vibration modes encompass non-standard longitudinal and bending vibrations. The structure and operating principle of the motor are described first. COMSOL Multiphysics models the stator’s vibration modes, frequency response, and 3-DOF motion. A motor prototype is manufactured and characterized to demonstrate the output characteristics of the motor. The results indicate that the motor has a no-load speed of 37 rpm along the x- and y-axes and up to 77 rpm along the z-axis. The maximum output torque of the motor is 25 Nm. The motor is low in height and compact, providing a method for further reducing the stator length of motors of the same type.

Enhancement of torque density and power density of polymer-based ultrasonic motors via flexible usage of anisotropy in elastic property

The carbon-fiber-reinforced poly phenylene sulfide (PPS/CF), which exhibits low density, low energy dissipation, and relatively high elastic modulus among polymers, is a promising material as the vibrating body of lightweight ultrasonic motors (USMs). Interestingly, the flexible usage of the anisotropy in PPS/CF’s elastic property (induced by carbon fibers’ reinforcement) offers a new idea to enhance the torque densities and power densities of the polymer-based USMs. As the key issue of flexibly using the anisotropy, this study aims to accomplish the optimal arrangement of the carbon-fibers’ filling direction according to the structure, the vibration mode, and the piezoelectric material’s polarization direction of the PPS/CF-based motor by performing model construction, structural optimization, and experimental verification. Initially, the dynamic model capable of setting PPS/CF’s anisotropically elastic moduli with the changeable filling direction is established to analyze the vibration characteristics. Subsequently, to increase the vibration velocity, the stiffness, and the electromechanical coupling factors, the optimization is carried out for the PPS/CF-based ring-shaped vibrators, where the optimal angle between the filling direction and the vibrator’s bottom surface is estimated as 60°. Finally, a prototype of the PPS/CF-based vibrator 30 mm in diameter and 8.5 mm in height is fabricated to form a rotary motor, whose movement and load characteristics are investigated through experiments. At 250 V voltage and 24.42 kHz frequency, the motor yields the no-load rotation speed, the maximal torque, and the maximal output power of 99.3 r min−1, 29.8 mNm, and 72 mW, respectively. Moreover, its torque density and power density reach respectively 7.1 Nm kg−1 and 17.1 W kg−1, relatively high among the rotary motors with polymer vibrating bodies. This study validates the effectiveness of our idea and also provides a basic approach to design lightweight USMs that employ newly-developed materials with anisotropically elastic properties and good vibration characteristics.

Speed Regulation and Optimization of Sensorless System of Permanent Magnet Synchronous Motor

Aiming at the problems of speed overshoot, slow convergence and poor anti-interference in the control of permanent-magnet synchronous motors (PMSMs) without a position sensor, a pulse vibration high-frequency signal injection method for a permanent-magnet synchronous motor with an improved sliding mode control was designed. Firstly, the improved approach rate function is combined with the improved non-singular fast terminal sliding mode surface to design the non-singular fast terminal sliding mode controller (NFTSMC), which is used in the speed loop to improve the speed convergence ability and reduce its overshoot. Secondly, in order to eliminate the influence of the band-pass filter on the system bandwidth in the traditional high-frequency injection method, a pulse vibration high-frequency signal injection method that injects high-frequency voltage signals and synchronous current signals into the d^ axis of the estimated two-phase rotation coordinate system d^q^ and the αβ axis of the two-phase stationary coordinate system αβ was designed to estimate the motor position and speed to achieve sensorless control. Finally, the above control strategy was compared with the speed loop PI and the traditional sliding mode controller (SMC) of the speed loop, respectively. The simulation and experimental results show that whether it is a no-load variable speed or fixed speed loading, the above control strategy can effectively reduce the speed overshoot, accelerate the speed convergence and improve the load capacity of the system.

A general structural design method, dynamics modeling and application study for built-in sandwich annular traveling wave piezoelectric transducers

This study first summarized a piezoelectric excitation source arrangement guideline for sandwich annular traveling wave transducers, which can excite ideal traveling waves for driving while ensuring consistent circumferential stiffness of the annular transducer. Consequently, a general structural design method was proposed for annular sandwich traveling wave piezoelectric transducers operating with out-of-plane traveling waves based on the above-mentioned arrangement guideline. Moreover, to study the vibration characteristics of the designed transducer based on the proposed method, an electromechanical coupled dynamics model was developed using the dynamic substructure method combined with the Lagrange equation. This model is universal and has guiding significance for the design and optimization of the same type of annular traveling wave piezoelectric transducers. Thereafter, the feasibility of the transducer structure design method and the correctness of the developed dynamics model were verified through appropriate vibration measurement experiments on the transducer prototype. The measured ideal mode shape and regular elliptical motion verified the feasibility of the transducer design method, and the comparison between the vibration measurement and theoretical model calculation results confirmed the correctness of the developed dynamic model. Finally, an application study of the proposed built-in sandwich traveling wave transducer was conducted to investigate its driving characteristics. The proposed transducer was used to drive a rotor to build a traveling wave piezoelectric motor. In addition, output performance experiments of the motor prototype were conducted. The experimental results indicated that under the driving conditions of 300 N pre-pressure, 500 Vpp voltage, and 19 kHz exciting frequency, the no-load speed of the motor was 19.04 RPM, its stall torque was 1.2 N·m, the maximum output power of the entire machine reached 0.6453 W, and its maximum output efficiency was 15.87%. Moreover, the normal operation of the rotating motor further verified the feasibility of the transducer structure design approach and the reliability of the drive application. The structural design method and the corresponding dynamic model proposed in this study are expected to have important guiding significance for the design and optimization of sandwich-type annular traveling wave transducers. Furthermore, the application investigation in this study provides a typical example for the traveling wave transducer.