Actuating mechanism and design of a T-type linear ultrasonic motor

To take advantage of merits of higher output-power and efficiency of bolt-clamped transducer,a T-type linear ultrasonic motor was proposed in this paper.The proposed motor contained a horizontal transducer and a vertical transducer.The horizontal transducer included two exponential shape horns,and the vertical transducer contained one exponential shape horn.And the horns intersected at tip ends where a driving foot was located.The longitudinal vibrations of transducers were excited by the stretching vibration of PZT ceramics.Longitudinal vibrations were superimposed in the motor and generated elliptical trajectory at the driving foot.The actuating mechanism of the proposed motor was analyzed.The two working modals of the motor were gained with FEM.The resonant frequencies of two working modals were degenerated by adjusting the structural parameters.The motion trajectory of nodes on the driving foot was gained by transient analysis.The vibration amplitude of node on the driving foot indicates that the proposed motor has potential good output characteristics.The results verify the feasibility of the proposed design and provide instructions for the development of the new ultrasonic motor.     

Design and optimization of the piezoelectric micromechanical ultrasonic transducer with an AlN thin film

Because existing ultrasonic transducers mostly use PZT and ZnO materials as piezoelectric thin films, while the PZT contains lead and ZnO has the problem of contaminating CMOS manufacturing, a piezoelectric ultrasonic micromechanical transducer with circular bi-laminate bending vibration which uses the aluminium nitride as the piezoelectric layer is designed. The working principle of the transducer is analyzed, the finite element model is established, and the finite element simulation is carried out for the size parameters of the transducer. It is found that the resonant frequency of the transducer is proportional to the thickness of each layer and inversely proportional to the square of the radius of the transducer; when the radius of the upper electrode is about 65% of the radius of the transducer, the resonant amplitude of the transducer is the largest; when the thickness ratio of the silicon and the aluminum nitride of the piezoelectric layer is about 0.6, the resonant amplitude is also the largest. The optimized transducer is simulated and compared with the original model. The results show that the working frequency in air is 9.21MHz, the electromechanical coupling coefficient increases from 21.44% to 27.16% in air and from 3.55% to 11.93% in water. These conclusions provide basic data for the research on the medical imaging probe.     

Working principle and design of a double cylinders type traveling wave ultrasonic motor using composite transducer

A double cylinders type traveling wave ultrasonic motor using composite transducer was proposed.The proposed stator contained two cylinders and one composite transducer,and the transducer located on the outer surfaces of cylinders.The composite transducer included two exponential horns located on leading ends,and the horns insected with the cylinders at tip ends.Two degenerated flexural vibration modes spatially and temporally orthogonal to each other were excited in each cylinder by the composite transducer.In this new design,a single transducer could excite two flexural traveling waves in the cylinders.Thus,elliptical motions were achieved at the particles on the teeth.The working principle of the proposed motor was analyzed.The cylinder and transducer were designed with FEM.The resonant frequencies of two vibration modals of the stator were tuned to be the same,and the motion trajectories of nodes on the teeth were analyzed.Transient analysis results show that the motion trajectories of teeth are ellipses.The results of this paper can guide the development of this new type of ultrasonic motor.     

超声导波电磁声换能器的研究进展

超声导波具有检测范围大、检测效率高等优点,广泛应用于板、管等典型波导结构的缺陷检测.作为超声导波换能器类型之一,电磁声换能器(electromagnetic acoustic transducer,EMAT)得到广泛关注和快速发展.综述了近20年来超声导波电磁声换能器的研究进展.主要包括:针对板和管结构超声导波检测的单模态EMAT结构设计;用于提高激励导波的能量和模态单一性的EMAT线圈与磁体结构参数的优化,针对非金属材料检测的新型贴片式EMAT的结构设计;阵列技术在EMAT性能优化上的应用和在缺陷定位和成像上的应用.     

IC引线焊接用超声键合换能器的优化控制

大规模集成电路芯片内晶片与IC引脚间的引线焊接常用基于超声键合压电换能器的超声波焊接工艺,因此超声键合换能器的控制性能直接影响了引线焊接质量及IC芯片的可靠性。该文在分析压电换能器特性的基础上,提出了一种对压电换能器特性参数进行自动辨识的扫频自学习方法,及基于调节器参数自整定的换能器优化控制方法,并介绍了以高性能DSP为核心的压电换能器控制系统的技术实现方案,该系统已在国际品牌的IC封装设备金线焊线机中得到应用。     

基于相位调整的三维超声微操纵技术

为了将超声辐射力应用到微机电系统领域,以达到对微构件进行无损、非接触遥操纵的目的,开展了三维超声辐射力场合成的理论与实验研究,提出了基于相位调整的三维超声微操纵技术.在研究单个圆形平面活塞换能器声场分布以及声场和辐射力关系的基础上,将以相同频率驱动的4个平面活塞换能器呈正四面体放置,利用声波合成原理获得三维超声驻波场,通过调整各个换能器发射信号相位之间的关系实现对微构件在空间范围内的俘获、移动、释放等操纵.实验结果表明,该技术能够有效地实现对微构件的三维操纵,具有响应速度快、定位精度高、易于控制、操纵范围广等优点     

Electromechanical coupling of 2-2 piezo-composite material

A dynamic mode) for 2-2 piezo-composite material was developed,in which the acoustic plane waves propagating along the interface were solved and their dispersion curves were obtained.By taking the resonator thickness as half a wavelength or its odd fold,the resonant frequencies of the composite transducers are in agreement with the dispersion curves.From the dynamic model the piezoelectric coupling coefficients for the thickness vibration of the composite could be obtained as a function of the composite thickness as well as the volume fraction of the ceramic phase.The results show that when the thickness vibration mode is decoupled with the lateral periodical vibration mode,the piezoelectric coupling reaches its maximum.This condition gives a maximum frequency bandwidth and a greatest piezoelectric coupling coefficient for the composite material.     

超声清洗设备功率自动监控电路的设计

为使超声清洗设备射频输出功率最大,要求超声换能器始终工作在谐振状态下。采用频率自动跟踪技术,并引入数字锁相环具体实现系统频率自动跟踪。仿真结果表明,所设计的超声清洗电路直流到射频输出功率转换效率较高;超声换能器上的电压、电流信号相位同步,换能器始终工作在谐振状态下。     

有机污水超声聚焦裂解设备中换能器的设计

在一种经济高效地处理高浓度、难降解有机污水“超声聚焦裂解”处理新方法的基础上，重点研究了变幅杆超声聚焦换能器的前、后盖板和聚焦变幅杆的结构设计数学模型，并且设计了适用于变幅杆超声聚焦换能器的控制电路，通过改变电路元件的相关参数，就可对超声频率和声压进行控制，以满足不同污水处理的要求。     

电涡流测距传感器信号的微机处理

通过理论分析和实验研究，找出了电涡流测距传感器的输出信号与被测距离、金属材料的性质及环境温度之间的关系，提出用单片机进行修正的方法，克服了现有电涡流测距传感器不能直读距离、通用性差、测量不准确的缺点。     

基于灵敏度解析的微机械陀螺结构优化方法

以一种音叉振动式微机械陀螺为研究对象,对其复杂多自由度模型的24个设计参数进行灵敏度解析,分别计算其对系统驱动模态和检测模态固有频率的动态灵敏度,筛选并确定出5个对最终输出性能影响最为关键的尺寸参数;以这5个参数为设计变量,并以系统输出特性作为优化目标对微陀螺结构进行了优化.灵敏度解析方法的应用有效解决了微陀螺结构优化过程中所存在的计算量大、解析时间长等实际问题,对相关MEMS器件的结构优化设计研究具有一定的参考价值.     

一种新型水声发射换能器的结构设计

换能器的结构参数和各部件的材料决定了换能器的性能。为了改善换能器的指向性,设计了一种新型结构的发射换能器。根据换能器的工作频率要求,利用换能器振子的共振频率公式计算了换能器的尺寸,使用有限元法对设计结构进行了仿真分析,并将振子的谐振频率与实际测量值进行了比较。结果表明,实测结果与理论估算及仿真值符合的较好,为换能器的结构设计提供了参考。     

复合型USM压电扭振子设计及其特性分析

介绍利用国产压电材料设计纵扭复合型超声波电机(USM)压电扭振子的理论和制造工艺,主要内容包括:压电材料的选取,压电扭振子的结构,根据等效电路推导出电机扭转振动模式的谐振频率方程,以及扭振子尺寸计算公式;根据实验总结了压电扭振子的制造工艺、黏接及其注意问题.并利用阻抗频谱分析仪测试了按上述理论设计的压电扭振子的频率特性.结果表明:设计理论、黏接剂的选择以及加工方法是合理可行的.据此研制的样机最大输出力矩已达10 Nm以上.     

高压电气设备泄露电流检测传感器的研究

电力设备绝缘在线监测技术已成为保证安全发电和供电、及时发现事故隐患、减少停电检修、提高供电可靠性的重要技术手段,高压设备绝缘在线监测的关键技术是泄露电流的采集,为此分析了单匝穿芯式与多匝串入传感器的结构原理,从变电所被测高压设备性能以及现场情况出发,阐述了单匝穿芯式传感器本身具有信号弱、稳定性差及难以长线传输等缺点,因此传感器设计时应采用多匝串入式;并对目前通用的三种铁芯材料即冷轧硅刚片、坡莫合金和超微晶合金的性能进行比较,分析了各种参数对传感器特性的影响,得出采用坡莫合金为铁芯材料可以增强输出信号幅值,减少误差,利用补偿;通过LDHL－250型漏电流传感器试验数据,对传感器特性进行了分析;指出影响传感器精度的主要因素,并提出对传感器误差减匝补偿、差动补偿和软件补偿方法。     

双质量块微振动陀螺设计与仿真

设计了一种能降低模态之间的机械耦合的电容式双质量块微振动陀螺.此陀螺能精确地匹配模态频率,而且可以克服重力加速度对输出检测电容的影响.利用ANSYS对结构进行了仿真和优化,得到驱动频率为1 010 Hz,检测频率为1 009 Hz,频率匹配系数达到0.099%.利用MATLAB进行系统仿真,得到结构灵敏度为31.61 fF/(rad.s-1)机械灵敏度为59.77 nm/(rad.s-1).     

大倾角采煤机电气控制系统设计

为在大倾角工作面上运行的电牵引采煤机,设计了四象限变频调速采煤机电气控制系统．介绍了控制系统的总体结构、组成和PLC的主控制回路．分析了变频调速系统的工作原理,并结合四象限变频器的硬件特点,设计了相应的变频器控制程序,两台变频器采用主／从控制方法,对左／右牵引电机进行一拖一控制,实现了牵引变频调速四象限运行．     

贴片式纵弯复合激励圆筒超声电机

为了有效提高贴片式环形行波超声电机的机械输出性能,利于超声电机的小型化和微型化,研制了一种贴片式纵弯复合激励圆筒超声电机,电机利用d33工作模式和d31工作模式,由单臂变幅杆和一个环形换能器构成,且变幅杆和换能器采用一体结构．在对电机的工作原理进行分析的基础上,利用ANSYS软件完成了电机的设计和仿真,实现了两个振动模态的特征频率简并,并采用多普勒激光测振仪对样机进行了振动测试,测试结果与仿真结果基本一致．样机的机械输出特性测试表明,样机的最大转速为268r／rain,最大输出力矩为1．1N·m．     

基于相控技术的钢板电磁超声检测方法

为了提高钢板中电磁超声回波信号,提出了一种基于相控技术的钢板电磁超声检测方法.研究了相控聚焦技术和钢板中电磁超声换能器的换能机理,通过多阵元组成激发换能器阵列,运用延时法使超声波在目标区等相位叠加,实现超声波聚焦,并在Q235钢板上采用分立式结构进行实验验证.结果表明:该方法有效弥补了收发换能器间声程差引起的相位偏移,激励电压一致时,658 mm处接收的回波信号幅值提高为中心换能器单独激发时的2倍;采用三阵元激励换能器阵列检测方法可实现缺陷处的超声波聚焦,520 mm处缺陷回波幅值提高为中心换能器单独激发时的1.83倍.     

芯片键合纵弯复合超声换能器的设计与试验

为了解决当前采用一维纵向超声加载模式进行芯片键合时造成结合面不充分的问题,设计纵弯复合超声能量加载模式的压电超声换能器,实现轴向纵振和水平弯振复合的超声振动代替传统单一的轴向振动. 采用ANSYS软件,对换能器有限元模型进行模态分析和谐响应分析,得到换能器纵振和弯振模态的谐振频率及振型. 通过调节换能器结构尺寸,实现纵振与弯振模态的简并. 采用阻抗分析仪对样机的频率和阻抗进行测试,使用激光多普勒测振仪测试换能器的纵振与弯振幅值,测试结果与有限元仿真计算结果一致,发现纵向与弯曲振幅均随着驱动电压的增加呈近似线性上升趋势, 证明设计的压电换能器实现了纵弯复合振动.     

新型优质的智能型压力变送器

介绍了一种由单片机8031开发的智能型压力变送器的电路结构,软件设计及实验分析。由于采用了多传感器的信息融合技术,在单片机的控制管理下实现了智能型压力变送器的非线性校正,通过模拟实验测出的标定数据的计算可知,校正后的多传感器的交叉灵敏度大大减少,从而提高了测量精度,性能的稳定性和运行的可靠性。