步进电机细分驱动控制系统设计与实现

针对步进电机容易失步,导致定位不准的问题,提出采用细分驱动控制的方法控制步进电机.首先对两相混合式步进电机进行了数学建模,并在Matlab/Simulink环境下对步进电机在不同细分数下进行了仿真研究,仿真结果表明细分驱动控制能显著提高步进电机运行性能.然后基于STM32F103处理器设计了细分驱动控制硬件系统并进行了测试,通过步进电机带动丝杆在700 mm范围内运动,在2细分、4细分、8细分、16细分状态下的误差分别为1.7、1.1、0.5、0.2 mm.测试结果表明,提高细分数能提高步进电机精度、降低噪声,本系统具有较强的实用价值.     

基于自动调焦显微视觉的MEMS运动测量技术

为了对微机电系统(MEMS)的机械动态性能进行测试,结合自动调焦、机器显微视觉和频闪照明成像等多项技术,设计了基于自动调焦显微视觉的MEMS动态测试系统,可进行MEMS平面运动和离面运动的测量。该文介绍了系统的设计组成和关键技术,并针对系统做了验证性实验。实验结果表明,平面亚像素位移算法的匹配精度可达1/50个像素,在系统25倍的放大倍率下,平面刚体运动测量分辨率达到7.2nm×8.3nm;自动调焦过程迅速,焦平面定位精确,离面运动测量分辨率达到0.1μm。     

激光干涉自动调焦原理和方法

论述采用激光干涉原理自动调焦的方法，被调焦的光学系统视为双光束干涉光路的一部分，从干涉纺中取得光学系统的调焦信息，通过由CC电器件，微机，步进电机组成的光电系统对离焦量进行检测和补偿实现自动调焦，这种方法与已有的相关法和对比度法相比，调焦精度高，易于实现，有较高的实用性。     

一种自动化微量液体加样模块的设计

微量液体加样在工业、实验室和医疗等领域有广泛的需求,设计一种自动化微量液体加样模块,通过对微量注射针传动结构地改进以及加样指标变差地原因分析设计了微量注射泵模块,采用微压力传感器和放大电路实现液面准确探测,使用P WM脉宽调制精准控制丝杆步进电机实现高精度微量液体加样.首先对自动化加样模块的机械结构进行建模设计,同时对微量注射针、丝杆步进电机、芯片等关键器件对比选型,根据微量注射针和电机参数分析计算驱动脉冲个数,设计了合理可靠的硬件电路、通信协议和软件.随后加工研制样机,最后对样机实物进行调试和测试,实现了自动化微量液体加样功能,关键指标达到了国标要求.     

DC-IV型食盐包装机的自动接膜装置设计

本课题是运用步进电机来设计一台食盐自动结膜机构。该机构主要是由底座,切膜接膜和控制部分组成,并且主要是针对机械部分进行了分析和设计,完成膜180°旋转刀自动切割自动接膜。在设计中,步进电机的运用是课题的关键,它可以将数字输入脉冲转换成旋转或直线增量运动的电磁执行,步进电机惯量低、定位精度高、无累积误差、控制简单等特点。在设计的最后,在控制系统中利用单片机对步进电机的控制进行了讨论。     

基于MSP430F169的步进电机控制系统

为使光电经纬仪调焦系统达到最佳成像效果,设计了基于MSP430F169单片机的步进电机位置控制系统.该系统采用电位计作为位置反馈元件,采用单片机内部A/D( Analog to Digital)定时采样位置信息,并与给定位置进行控制位置误差对比.硬件系统包括单片机及接口电路、电机驱动电路、液晶显示电路和键盘.结合硬件电...     

微型步进电机动态特性测试的研究

本文提出了一种应用激光多普勒效应对微型步进电机和其他微型精密机构进行动态特性测试的新方法。由于采用微型计算机进行自适应定标,这种测试是定量和高精度的。在理论分析的基础上研制了一种测试系统,并用该测试系统对石英钟走的微型步进电机进行动态测试,所得动态特性曲线与理论分析是相吻合的。这种测试力法由于是一种非接触测量法,因此测试结果完全反映机构的实际运动情况。这种方法还可推广应用于其他精密机构的动态测试上,因此是一种很有前途的测试方法。     

基于驱动电路3955的步进电机细分驱动器设计

为减小步距角,提高电机步进分辨率,在分析步进电机细分原理的基础上,提出一种基于全桥PWM驱动电路3955的两相步进电机细分驱动器设计方案,给出了系统的硬件结构和软件设计。该方案采用正弦/余弦细分方法,控制步进电机两相绕组的电流,实现了斩波恒流均匀细分驱动,最高细分达到128。所设计的驱动器已应用于数控车床改造中,采用导程为1 mm的精密滚珠丝杆,可实现每步位移0.4μm。实验结果表明该步进电机细分驱动器运行平稳、可靠性高,具有良好的运行矩频特性。     

2LB—160型大功率步进电机试制成功

功率步进电机,是七十年代世界上的新产品,是数控机床或自动线中重要的组成部分。大功率步进电机,由于它的输出转矩比较大,因此在特定数控线路的指挥下,可以通过丝杆直接驱动机床的工作台,从而代替了电液、油压系统等一系列装置,使传动环节少、结构简单可靠、精度高、调整维护方便。     

两相混合式步进电机的响应及转速波动

通过分析两相混合式步进电机的机械结构,理论推导了影响步进电机起动过程的多种因素.搭建了一套基于光电传感嚣的步进电机性能参数测量系统,并编写了数据收集和处理的软件.应用此系统对不同批次的步进电机进行了测试,实测数据与理论分析基本吻合.最后,从电机应用的角度,提出了改进步进电机起动过程性能参数的方法.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.