超声引线键合PZT驱动信号采集分析系统

根据超声引线键合实验平台电路结构,设计了PZT(压电陶瓷)驱动信号采集电路.在此基础上开发了基于LabView和Matlab的信号采集分析系统.针对PZT驱动电压和电流信号特征,提出了瞬时频率、相差和有效值曲线的计算方法,获得了实际键合试验过程中电流电压瞬时频率及相差变化规律.并根据有效值曲线特征,提出了分段特征点提取方法.根据大量试验分析了分段特征点的稳定性,这对于键合机理研究具有重要意义.试验结果表明,系统稳定可靠,能有效采集分析键合过程中的PZT驱动信号.     

铝箔恒压轧制机理探讨(2)

三、恒压轧制与板形稳定上述力学模式,表明了轧制过程各变形量之间的内在联系。运用变形协调方程对实际轧     

Relationship between rheological manufacturing process and optical performance of optical fiber coupler

Through theoretical analysis and experiments, the viscoelastic mechanical model of optical fiber coupler in the process of fused biconical taper was established, and the numerical analysis in non-uniform temperature field was made. The results show that the rheological parameters, such as drawing speed and fused temperature, have a tremendous influence on stress distribution and performance of optical fiber coupler, especially the influence of fused temperature. The change of fused temperature by 5 ℃ can lead to the change of the maximum stress by 30% and stress difference by 20% in the same cross section. The change of temperature gradient by 3% can result in the change of stress difference by 90%. In the present condition of rheological technology, rheological defects such as crystallizations and microcracks are easy to generate in the optical fiber coupler.     

Thermal contact conductance at continuous roll-casting interface

The effects of surface roughness, strain rate, friction coefficient and pressure on real contact area were analyzed based on the research of Stupkiewicz. The real contact area model taking account of the effect of friction and deformation of material was obtained. The model of contact conductance at the rolling interface was obtained by integrating the specific feature of heat transfer through the interface of continuous roll-casting. The results indicate that the real contact area increases obviously when the material is under yield, and the real contact area varies inversely with surface roughness, whereas it varies exponentially with friction coefficient, strain rate and pressure, and the power factor depends on strain rate.     

基于退火遗传算法的复杂机电系统控制参数最优整定

针对复杂机电系统中可调参数多、调整范围大、参数之间耦合强、常规方法难于整定与组态的难题，提出了基于退火遗传算法的参数最优整定方法．将遗传算法和模拟退火算法巧妙地结合起来、取长补短，构成一种新的高效、鲁棒的寻优算法，应用于平整机主传动速度控制系统的参数优化问题，使系统的性能指标达到最优．     

Rheological behavior of continuous roll casting process of aluminum alloy

The rheological behavior of aluminum alloy and its influencing factors in physical simulation of continuous roll casting process were studied by using a Gleeble-1500 thermal-mechanical simulation tester with a set of special clamp system. The relationships between the flow stress and the strain rate in the deformation process of simulating roll casting experiment were obtained. The results show that four different characteristic stages exist in the temperature range of the whole rheological process. The first occurs when the temperature is higher than 600℃, which belongs to the creep deformation stage; the second occurs when the temperature lies in the range of 500 - 600℃, and it can be regarded as the high temperature and low stress level deformation stage; the third occurs when the temperature decreases to the range of 300 - 500℃, it is considered to be the middle stress level deformation stage; the last occurs when the temperature is less than 300℃ and the strain rate is less than 1.00 s^-1 , it belongs to middle stress level deformation stage. But when the strain rate is larger than 1.00 s^-1, it belongs to the high stress level deformation stage. And the relative constitutive models suitable for the four different stages of continuous roll casting process were established through multivariate linear regression analysis of the experimental data.     

Influences of polishing on return loss of optical fiber connectors

With Al2O3 and SiO2 as polishing medium, under different polishing conditions, e.g. with different polishing pressure, polishing time and polishing fluid, the influences of polishing treatment on the return loss of optical fiber connectors were investigated. The return loss of optical fiber connectors is 32-38 dB before polishing. The resuits show that dry polishing(i, e. no polishing fluid) with Al2O3 has less influence on return loss of optical fiber connectors, while dry polishing with SiO2 reduces return loss to about 20dB because of the end-face of optical fiber contaminated. The wet polishing(i, e. using distilled water as polishing fluid) with Al2O3 or SiO2 can increase return loss to 45-50dB, but wet polishing with Al2O3 may produce optical fiber undercut depth of 80-140nm. Wet polishing with SiO2 should be preferentially selected for optical fiber connectors and polishing time should be controlled within 20-30s.     

ARMAX模型参数估计的智能搜索辨识方法

基于基因搜索技术,建立了ARMAX模型参数的智能搜索辨识方法.提出了一种通过ARMAX模型零极点变换确定模型系数取值范围的间接方法及非可行域内染色体的修复方法.在遗传算法实现中,通过设计自适应适值函数来调整选择压力,设计自适应交叉概率,对传统的交叉和变异操作进行改进,嵌入基于Metropolis准则的"灾变"操作,采用精因保护策略,改善了遗传算法的全局搜索和局部寻优能力,加速了寻优过程.有关算例证明了本文方法的有效性.     

解耦设计中分布式并行协同求解方法

随着并行工程,分布式人工智能学科的发展,从分布式协同求解角度进行解耦研究成为复杂机电系统的重要研究方向。作者介绍了基于分布式并行协同求解进行解耦设计的组织原则和策略,描述了协同求解智能主体的内部结构和功能模块,说明了每一智能主体的工作机理,并进而对协同示解过程中的通信机制作出初步设计。     

多智能体并行设计环境中的自然语言通信功能

研究了一个多智能体并行设计环境中自然语言通信模块的设计和实现方法，该设计方法建设在受限语言的基础上，突出了在协商式多智能体之间进行自然语言通信时的准确性，通过建立一个受限词汇的综合信息库，记录词汇的各种语法，语义信息；描述了词库的结构和形态，为了区分基本词汇和面向用户领域词汇，将词库分级；在词法分析时采用总库索引来查询词汇库，并提出了提高词库性能的方法，限定了用户使用的基本句型，采用的充短语结构文法对句子结构进行分析，并产生相的语义逻辑公式，定义了句了生成模板，智能体借助模板提供的接口函数生成自然语言句子。此外，还提出了提高通信有效性的方法，为智能体提供了灵活，友善的接口，提高了多智能体并行设计环境的性能。