Related Experiment Video
Updated: Jun 27, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Mechanism of Ultra-Low-Speed Smoothness in Ultrasonic Motors Based on a Macro-Micro Multi-Scale Finite Element Model
Weijun Zeng1, Tong Xie1, Qiaoliang Peng2
1Rail Transit School, Zhejiang Institute of Communications, Hangzhou 311112, China.
Micromachines
|June 26, 2026
Summary
A new superimposed pulse driving method significantly reduces speed fluctuations in ultrasonic motors, enabling smooth ultra-low-speed operation crucial for semiconductor packaging. This method overcomes limitations of traditional microstepping, offering precise control.
Area of Science:
- Mechanical Engineering
- Materials Science
- Robotics
Background:
- Conventional microstepping driving methods exhibit significant speed oscillations at ultra-low speeds, hindering ultrasonic motor applications in semiconductor packaging.
- Existing ultrasonic motor theories often oversimplify, neglecting crucial factors like surface microstructure and multiphysics coupling, leading to experimental discrepancies.
Purpose of the Study:
- To develop and validate a macro-micro multi-scale finite element model for traveling-wave ultrasonic motors.
- To compare the performance of a superimposed pulse driving method against traditional microstepping for ultra-low-speed operation.
- To elucidate the mechanism behind the smooth operation achieved by the superimposed pulse driving method.
Main Methods:
- Established a macro-micro multi-scale finite element model using ADINA and HyperMesh, incorporating nonlinearity and multiphysics coupling.
- Utilized ultrasonic friction reduction theory and beat traveling wave mechanism for analysis.
- Validated simulated stator mode shapes with laser scanning vibrometry and conducted speed tests from 200 to 320 arcsec/s.
Main Results:
- The superimposed pulse driving method reduced speed fluctuation rate from 228% to 32% at a target speed of 900 arcsec/s.
- Experimental results confirmed consistently lower speed fluctuations for the superimposed pulse method across the tested range.
- Identified single-peak dominance and smooth zone alternation as key mechanisms for the superimposed pulse method's smooth operation.
Conclusions:
- The superimposed pulse driving method fundamentally overcomes the limitations of microstepping for ultra-low-speed ultrasonic motor control.
- The developed multi-scale model provides a valuable tool for precise quantitative computation and understanding complex motor behaviors.
- This research offers a new method and reference for ultra-low-speed precision control in ultrasonic motors and similar devices.
Related Concept Videos
01:30Typical Model Studies
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
01:12Modeling and Similitude
Scaled modeling is a fundamental technique in engineering, enabling the study of large and complex systems by creating smaller, manageable replicas that recreate critical characteristics of the original. In hydrology and civil infrastructure, for example, scaled models of dams help analyze water flow, turbulence, and pressure. This method allows for accurate predictions of real-world behavior within a controlled environment, significantly reducing the cost and time involved in full-scale...
01:21Design Example: Creating a Hydraulic Model of a Dam Spillway
Scaled hydraulic models of dam spillways provide a practical way to replicate and study the intricate flow dynamics of these structures. Often built to a 1:15 ratio, these models allow for observing critical water behavior, such as velocity distribution, flow patterns, and energy dissipation.
01:22Mechanical Systems
Mechanical systems are analogous to to electrical networks where springs and masses play similar roles to inductors and capacitors, respectively. A viscous damper in mechanical systems functions similarly to a resistor in electrical networks, dissipating energy. The forces acting on a mass in such systems include an applied force in the direction of motion, counteracted by forces from the spring, a viscous damper, and the mass's acceleration. This interplay of forces is mathematically described...
01:23Design Example: Deciding Thickness of Lubricating Fluid in a Shaft
Effective lubrication between a rotating shaft and its bearing housing is essential in rotating machinery to minimize friction, wear, and energy loss. With carefully controlled thickness and viscosity, the lubricant layer prevents metal-to-metal contact, ensuring smooth operation.
To calculate the required thickness of the lubricant layer, the tangential velocity at the shaft's surface must first be determined. This velocity is calculated by converting the rotational speed to angular velocity...
To calculate the required thickness of the lubricant layer, the tangential velocity at the shaft's surface must first be determined. This velocity is calculated by converting the rotational speed to angular velocity...
01:15Thin-Walled Hollow Shafts
In analyzing a thin-walled hollow shaft subjected to torsional loading, a segment with width dx is isolated for examination. Despite its equilibrium state, this segment faces torsional shearing forces at its ends. These forces are quantitatively described by the product of the longitudinal shearing stress on the segment's minor surface and the area of this surface, leading to the concept of shear flow. This shear flow is consistent throughout the structure, indicating a uniform distribution of...