查询词典 USM

This dissertation first puts forward the model of driving force transformation which the contact region of stator and rotor is divided into three relative sliding areas such as braking—driving—braking by means of research on vibration characteristics of USM stator surface points and micro driving course to rotor, this model can explain variation regularity of USM load characteristics, moreover, simplified calculation formula of rotor driving force concerned with stator teeth is set up.

本文通过对行波超声马达定子表面各点的振动特性和定子对转子微观驱动过程的研究，首次提出将定子和转子接触区划分为制动区—驱动区—制动区三个相对滑动区的驱动力转换模型，这一模型能够解释超声马达负载特性变化规律，并建立了计及定子齿的转子驱动力计算简化公式，该式能应用于多于两个定子齿驱动的转子驱动力计算。

Electric machinery and electrotechnology ; USM ; Adaptive control ; RBF ; Neural network ; Identification

电机电工；超声波电机；自适应控制；经向基和数；神经网络；参数辨识

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

The system is made up of the mechanical structure, which includes stent, robot-arm and lifting base, and control system, including the PC, USM and the controller.

该系统主要由机械结构和控制系统组成。机械结构由支架、机械臂和系统升降台等组成，控制系统由上位计算机、超声电机及控制器组成。

An example is the new Unsharp Mask filter.

一个例子是新的USM锐化过滤器。

There is a simple yet elegant fix for this, and surprisingly it is done by using the Unsharp Mask filter.

有一个简单但绝对一流的办法来解决这个问题，答案可能会出人意料，是 USM锐化滤镜。

For this particular scan, I ran the unsharp mask filter at the setting shown below 4 times.

在这幅图里，我运行了4次USM锐化

To determine applicability of the proposed method, Experiments have been done by means of the USM and driver designed above.

为计算复合型USM的频率特性，本文根据定振子的具体结构特点，分别对纵、扭振子的等效电路进行了推导。

However, tool wear is high in USM, due to the abrasive cutting action.

但是，由于USM是磨削加工，因而刀具损耗大。

I was so excited to pick up my new lens, the Canon EF 24mm f/1.4L II USM.

我非常兴奋，这可是我的第一颗 L 镜，佳能 EF 24mm f/1.4L II USM。

The labia have now been sutured together almost completely.The drains and the Foley catheter come out at the top.

此刻阴唇已经几乎完全的缝在一起了，排除多余淤血体液的管子和Foley导管从顶端冒出来。

To get the business done, I suggest we split the difference in price.

为了做成这笔生意，我建议我们在价格上大家各让一半。