基于分数阶LMS的AEM系统次级通道辨识

利用分数阶算法对经典LMS进行改进，并对发动机主动悬置系统的次级通道开展辨识，完成了不同分数阶次下的辨识试验，与经典LMS算法的辨识结果进行了对比，最后进行了振动主动控制试验。结果表明：在保证AEM系统振动主动控制效果的前提下，分数阶LMS相比于经典LMS具有更快的收敛速度，能改善算法的控制精度等优势。     

压电复合材料薄壳结构振动主动控制

对表面粘贴压电元件的复合材料薄壳结构的应变驱动原理、振动控制方程进行了分析。建立了自适应控制系统，对粘贴了压电材料的玻纤／环氧圆柱壳的振动进行了主动控制实验。结果表明，压电自适应壳结构能对薄壳的振动进行有效抑制，同时使壳体噪声辐射得到显著衰减。     

压电智能挠性板的主动振动控制研究

对挠性悬臂矩形板的主动振动控制进行了研究。给出了悬臂板的压电敏感器和致动器的布置准则，并推导了悬臂板的（包括弯曲和扭转振动模态）基于分布式压电致动器的压电致动方程，可以根据该方程设计悬臂板压电主动振动抑制的控制器。该文在控制方法上采用应变律反馈控制和线性二次型（LQR）控制，计算机数字仿真结果表明：设计的控制律对于悬臂板的弯曲和扭转振动是有效的。     

基于ARX模型的压电智能结构振动预测控制

采用预测控制法对压电智能结构的振动主动控制进行了实验研究，通过实验方法建立了系统的ARX模型，并在此基础上设计了预测控制器对结构进行振动主动控制。实验结果验证了该方法在压电智能结构振动主动控制中的可行性和有效性。     

智能桁架结构振动控制中压电主动构件的研究：（一）压电主动构件设计

基于压电材料的压电作动效应，设计了一种可用于智能桁架结构振动控制的直线式压电主动构件，讨论了设计理论、参数选取及其对压电主动构件性能带来的影响。     

两自由度柔性臂压电陶瓷抑振方案优化设计

振动控制是柔性臂控制的主要任务。两自由度柔性臂系统是非性线系统，并且存在强运动耦合，模型复杂。因此有效的抑振方案对柔性臂控制至关重要。该文以两自由度柔性臂残余振动分析为依据，对压电陶瓷作动器与振动传感器的布置位置进行了优化设计，提出了压电陶瓷作动器与振动传感器相结合的抑振方案。实验证明这种抑振方案是有效的。     

PZT机敏支架振动主动控制的实验研究

通过机敏结构建立了三维支架的振动主动控制系统，给出了压电机敏结构的离散控制方程，采用加速度反馈实现了支架的振动主动控制     

超精密机床的压电作动器隔振系统研究

压电作动器是振动主动控制中最常用的一种执行机构。文章分析了各种压电作动器的特点及应用范围 ,并用压电陶瓷作动器对超精密机床实施振动主动控制。结果表明 ,该系统应用控制器克服了压电元件的迟滞特性、蠕变特性和非线性后 ,能有效的控制地基振动对超精密机床的影响 ,提高了超精密机床的加工精度     

周期性压电分流薄板结构振动控制方法研究

为降低薄板振动产生的辐射噪声,采用将分流压电振子周期性固定于薄板上的方式进行振动控制,因结构符合周期性所以能够衰减压电薄板的振动量从而抑制薄板产生的辐射噪声。分别利用有限元法和传递矩阵法建立分流压电薄板的理论模型和弹性波传播理论模型,分析了压电薄板对振动衰减的原理,研究了3种分流电路调谐频率对压电薄板振动衰减的影响。结果表明,当电路调谐频率为850Hz时,压电薄板的振动衰减量最大。     

智能机械臂的压电半主动振动控制

以在半主动控制领域具有良好应用前景的压电元件为基础,在受控机械臂上粘贴压电陶瓷(PZT)片,运用基于压电分流阻尼的振动被动控制和基于同步开关阻尼(SSD)技术的半主动控制理论,消耗机械臂振动的机械能,减小结构振动的位移幅度,从而达到振动控制的目的.     

天线传动系统扭转振动固有频率计算分析

天线座结构振动频率的计算是天线座结构设计的重要内容,为了提高结构频率,优化结构设计,本文对其传动系统扭转振动的固有频率进行了计算分析。     

Evaluation of diffusion patterning as an alternative substratetechnology for automotive applications

In automotive applications, electronic circuits are becoming more sophisticated in terms of functionality, power, and density. Specifically, the engine control unit (ECU) is being moved to direct engine mounting, minimizing interconnection length, reducing interference, and simplifying assembly and testing. This type of mounting will reduce the overall manufacturing cost. Therefore, the electronics have to survive higher working temperatures, vibration, and wider temperature excursions during on/off and temperature cycles. These requirements have been the driving force for robust multilayer substrates. Diffusion patterning (DP), a multilayer dielectric technology developed by DuPont Electronics, is evaluated for next generation ECUs. This high density thick film technology achieves via formation through a complex chemical reaction utilizing an imaging paste. Moreover, the DP technology may incorporate buried resistors and capacitors. Using the DP technology, engine controllers with both four-layer and six-layer structures have been built. The six-layer substrate contains several buried resistors and capacitors. This paper discusses the critical parameters in fabrication of these substrates. The processibility and capacitance variations with different process parameters and firing conditions are also presented. Another aspect of DP technology is that it is compatible with surface mount and flip chip technology. Long term reliability testing of flip chips on DP substrates has been performed. After 4000 cycles, reliability data were excellent; no failures were identified. Reliability test results will be reviewed     

振动对航空相机成像质量影响的分析

文章分析了振动因素对航空相机成像质量的影响,建立了光学影像降低与振动的关系式,并结合工程实际进行了量化分析,提出了进行减震设计的基本思路。     

基于LabVIEW的发动机数据采集系统

针对在发动机数据采集过程中,对速度和精度的要求,基于虚拟仪器,利用振动传感器、麦克风、信号调理电路、PCI-4472B数据采集卡,计算机等硬件,对吉利三缸A8发动机的振动信号及排气噪声进行采集,设计出了发动机数据采集系统。实践表明,该系统可靠、稳定,有很大的实用价值,为诊断和监测发动机故障打下良好的基础。     

Measurement and control of torque ripple-induced frame torsional vibration in a surface mount permanent magnet machine

A sensor to measure the stator torsional vibration due to torque ripple produced by a surface mount permanent magnet machine is first described. The sensor is relatively inexpensive and is straight forward to incorporate into a drive system. Experiments are performed to validate that the voltage produced by the sensor is linearly related to torque ripple amplitude. Closed-loop controllers are then described that adjust the stator current harmonics applied to the machine to achieve a commanded average torque while mitigating measured torsional vibration. Simulation and experimental results are used to demonstrate the effectiveness of the control techniques.     

Vibration reliability characterization of PBGA assemblies

Generally, the low-cycle fatigue induced by thermal cycling is the major concern in the reliability of surface mount technology for electronic packaging, but the high-cycle fatigue induced by vibration can also contribute significant effect, especially for applications in automobile, military, and avionic industries. To assess vibration induced fatigue failures, the dynamic properties of printed circuit board (PCB) assemblies play a very important role. In this paper, the dynamic properties of a plastic ball grid array (PBGA) assembly were characterized by using experimental modal testing and finite element analysis. The bare PCB and PCB assembly with PBGA modules mounted were tested and analyzed separately, so that the influence of PBGA modules on the PCB’s dynamic properties could be identified. It was found that mounting PBGA modules to PCB increased the stiffness of the PCB. Results of constant-amplitude vibration reliability testing of the PBGA assembly are also reported. It was found that the PBGA assembly was vulnerable to vibration, and fatigue failure always occurred at the corner solder balls of the PBGA module.     

Modal Analysis and Study of the Vibration Characteristics of the Thermoelectric Modules of Vehicle Exhaust Power-Generation Systems

Thermoelectric (TE) materials and modules are important components of vehicle exhaust power-generation systems. The road and the engine, the main sources of vibration of TE modules, have substantial effects on the vibration characteristics of TE modules. In this work, modal analysis and the vibration characteristics of TE modules were investigated in detail. On the basis of the TE modules and their service environment, simulations for modal analysis were performed by use of the finite-element method, and the natural frequencies and mode shapes of the TE modules were obtained. The numerical results were used to compare the natural frequencies of TE modules under different contact stiffness with the range of excitation frequencies of road and engine, in an attempt to prevent severe resonance. The effects on the vibration characteristics of geometric dimensions, service temperature, and thermal stress of the TE modules are also discussed in detail. The results reveal the vibration characteristics of the TE modules and provide theoretical guidance for structure optimization in the design of vehicle exhaust power-generation systems.     

Short pulse techniques for estimating the temperature and impurity concentration of the active layer of a Gunn diode

A coaxial mount has been designed to allow the short pulse current-voltage characteristics of a Gunn diodes to be measured at various ambient temperatures. The results can be used, in conjunction with c.w. measurements, to estimate the temperature of the active layer and provide a simple means of comparing the thermal properties of both different forms of diode construction and heat sinking. The mount can also be used in an experiment to estimate the impurity concentration of the diode.     

应用于雷达TR组件微组装中的气相清洗技术

随着相控阵雷达技术的发展,大规模应用了裸芯片等能够减小组件体积、减轻组件重量的精密元器件。然而这些元器件在基板贴装元器件的微组装过程中,容易在采用常规清洗手段产生的机械力作用下损伤,需要寻找无损的清洗手段。而气相清洗以其无机械力作用、无振动的特点正在受到越来越多的关注。文中以实际生产中组件内常见污染物为例进行气相清洗,并对清洗效果进行了评价和分析。     

光纤式航空发动机叶片边角振动测量系统

"光纤式航空发动机叶片边角振动测量系统"用于将航空发动机多达44路的测试信号通过光纤传输.该系统具有非接触、传输速率高、抗干扰能力强和信号质量好等优点,很好地解决了发动机参数测试问题.介绍了系统的测试原理,所要解决的关键技术,以及最终获得的研究成果等.