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In-plane bending traveling wave ultrasonic motors (USM), which are compact in structure and flexible in design, have been widely applied in biological engineering, optical engineering, and aerospace engineering. However, the high driving voltage and complicated driving circuit of this kind of USM restrict their further miniaturization and electromechanical integration in these applications and bring some potential safety hazards. To solve this problem, a low-voltage-driving traveling wave USM incorporating cofired multilayer piezoelectric ceramics was proposed in this work. Four cofired piezoelectric ceramics were strategically designed to excite two orthogonal third-order in-plane bending modes with the same frequency of the USM. The principles of traveling wave synthesis and low-voltage-driving of the USM were deduced, and the stator dynamic design and transient dynamic simulation were carried out by finite-element method. The microproperties of cofired piezoelectric multilayer ceramics, the vibration characteristics of the stator, and the mechanical output performance of the USM were tested by experiments. The results indicated that the motor can work as low as 5 $\text{V}_{\text {p-p}}$. A long stroke with a maximum forward and reverse rotational speeds of 187.7 and 176.6 r/min were obtained, respectively, and a maximum stalling torque of 4.8 mN $\cdot$ m at 47.3 kHz under 15 $\text{V}_{\text {p-p}}$ was achieved. The results showed that the proposed USM is small, low in driving voltage, and high in torque output, which has promising applications in aerospace, biomedicine, and other fields that require a lightweight and integration of driving devices. [ABSTRACT FROM AUTHOR]

The traditional dynamic models of linear ultrasonic motor (LUSM) do not consider the influences of the preload force and the roughness of the contact surface of stator/slider on the performance of the motor, which unable to effectively describe the dynamic behavior of the motor. In this paper, a dynamic model is established for a V-shaped LUSM considering the influence of the preload force and the roughness of the contact surface of stator/slider on the dynamic behavior of the motor. The contact mechanism of the stator/slider and the influence of preload force on the stator parameters are studied and analyzed. The effectiveness of the developed model is verified by comparing with the analytical model that ignored the effect of the preload force on the stator parameters. The experimental results shown that the developed model can accurately reflect the dynamic characteristics of the motor, and the model will be helpful for the function prediction and precise control of the motor. [ABSTRACT FROM AUTHOR]

Existing 3-D intravascular ultrasound (IVUS) systems that combine two electromagnetic (EM) motors to drive catheters are bulky and require considerable efforts to eliminate EM interference (EMI). Here, we propose a new scanning method to realize 3-D IVUS imaging using a helical ultrasonic motor to overcome the aforementioned issues. The ultrasonic motor with compact dimensions (7-mm outer diameter and 30-mm longitudinal length), lightweight (20.5 g), and free of EMI exhibits a great application potential in mobile imaging devices. In particular, it can simultaneously perform rotary and linear motions, facilitating precise 3-D scanning of an imaging catheter. Experimental results show that the signal-to-noise ratio (SNR) of raw images obtained using the ultrasonic motor is 5.3 dB better than that of an EM motor. Moreover, the proposed imaging device exhibits the maximum rotary speed of 12.3 r/s and the positioning accuracy of 2.6 $\mu \text{m}$ at a driving voltage of 240 Vp-p. The 3-D wire phantom imaging and 3-D tube phantom imaging are performed to evaluate the performance of the imaging device. Finally, the in vitro imaging of a porcine coronary artery demonstrates that the layered architecture of the vessel can be precisely identified while significantly increasing the SNR of the raw images. [ABSTRACT FROM AUTHOR]

In this study, a large thrust linear ultrasonic motor using an L-shaped stator is described. The stator is constructed by two mutually perpendicular rectangular plate vibrators, one of which is mounted in parallel with the slider to make the motor structure to be more compact. The symmetric and antisymmetric modes of the stator based on the first order bending vibration of two vibrators are adopted, in which each resonance mode is assigned to drive the slider in one direction. The placement of piezoelectric ceramics in a stator could be determined by finite element analysis, and the influence of slots in the head block on the vibration amplitudes of driving foot was studied as well. Three types of prototypes (non-slotted, dual-slot, and single-slot) were fabricated and experimentally investigated. Experimental results demonstrated that the prototype with one slot exhibited the best mechanical output performance. The maximum loads under the excitation of symmetric mode and antisymmetric mode were 65 and 90 N, respectively. [ABSTRACT FROM AUTHOR]

The precision rotary stage plays a prominent role in the operation of precision drive equipment and mechatronics. However, the existing precision rotary stages are challenging to juggle the characteristics of low-voltage drive and high precision. This paper represents a precision positioning rotary stage driven by multilayer piezoelectric stacks, which can achieve stage rotating with low voltage and high precision. The rotary stage is driven by the interaction between a cylinder-type stator and a rotor, utilizing the third-order in-plane traveling wave vibrations. The contact model between the stator and the rotor is built. The prototype of the stage was made and the test experiment was completed. The experimental results show that the stage considers comprehensively the characteristics of high precision (the resolution is 27.53 μrad), and low-voltage drive(driving voltage as low as 5 Vp-p). The maximum speed of the proposed stage is 1039 r/min and the speed under a 200-g load is 30.23 r/min. The rotary stage shows tremendous potential in the field of the precision drive. • The piezoelectric drive method can achieve can realize high precision driving. • Multilayer piezoelectric stacks are used to excite in-plane bending vibration. • The stage juggles the characteristics of low-voltage drive and high precision. • The proposed stage has application potential in the field of precision drive. [ABSTRACT FROM AUTHOR]

• A thermal-mechanical-electric coupling dynamic model is developed for a V-shaped linear ultrasonic motor. • The influence of surface roughness on the temperature rise of the motor is taken into account in the model. • The model can be used to predict the output characteristics of the motor. In this paper, a thermal-mechanical-electric coupling dynamic model is developed for a V-shape linear ultrasonic motor. The impact of surface roughness of stator/slider on the motor temperature rise as well as the temperature dependence of the stator material parameters are considered in this model. The relationship between the resonant frequency of the stator and the temperature is investigated, and the variation relation of motor parameters with regard to the temperature is discussed. The validity of the model is verified by numerical simulation and experimental results. Based on the proposed model, the influences of surface roughness of stator/slider, driving voltage, driving frequency and pre-pressure on motor temperature and velocity are studied and analyzed, and the comparison between the measuring data and the previous reported model with constant parameters are conducted. The results denote that the established model under different input parameters can be more accurately to predict the dynamic changes of temperature and velocity of the motor, which will be a valuable guide for the improvement of precise control and long-term stable operation of the motor. [ABSTRACT FROM AUTHOR]

Highlights • Establishing a complete 3D FE model to study the TRUMs. • It can help to know the motor's mechanical capacity before prototype manufacture. • The actual contact mechanism between stator and rotor is reflected accurately. • Torsional deformation of the rotor during rotation can be obtained. • Simulations can facilitate the stress analyses to avoid the failure of USMs. • Providing a powerful tool for structure design and performance prediction of USMs. Abstract To evaluate the response and output performance of an assembled and complete ultrasonic motor, a 3D finite element model has been proposed by a commercial finite element software ADINA. The simulated results of the output performance can be obtained, which are in good agreement with the available experimental data. Therefore, it is convenient to know the mechanical capacity of the motor before prototype manufacture. Moreover, the radial, circumferential and axial displacements of the contact nodes are acquired to simulate the real elliptical motions of the stator. Without assuming that the rotor behaves as a rigid body, the actual contact mechanism between the stator and rotor is reflected accurately. The simulation shows the distinct stress concentration issue of the motor, which can facilitate the stress analyses to avoid the failure of the motor. This study provides a powerful tool for the structure design and performance prediction of the ultrasonic motor. [ABSTRACT FROM AUTHOR]