基于嵌入式Linux的模拟泄漏控制系统设计

针对在标定气体泄漏检测设备的检测精度时,传统标定平台存在操作过程繁琐、测量误差大和便携性差等问题,研究分析了模拟泄漏的原理,建立了模拟泄漏率与步进电机转速之间的关系,设计了一种基于嵌入式Linux的模拟泄漏控制系统。根据系统的功能需要设计了系统的硬件电路,并基于Linux+Qt的开发环境设计了系统的控制程序和人机交互界面;通过对S3C2440定时器TOUT0端口的PWM脉宽调制,准确控制了步进电机的转速;同时采用S3C2440的外部中断EINT0准确统计了光电编码器发出的脉冲数,实时得到了实测模拟泄漏率,并对其误差和实时稳定性进行了实验分析。实验结果表明:该系统达到了标定气体泄漏检测设备时对模拟泄漏精度和稳定性的要求,可为气体泄漏检测设备提供方便可靠的标定平台。     

虚拟仪器技术在LAMOST光纤定位系统中的应用

介绍了一套基于虚拟仪器技术的应用系统,该系统可以应用于步进电机扭矩的测量.系统对步进电机及其驱动电路进行实时检测,实现了驱动电压和步进电机绕组电流的多通道同步数据采集与状态分析,并将分析结果反馈至控制主机,控制主机根据反馈结果做出相应的决策.系统还实现了步进电机零位的模拟控制和实时监测.基于虚拟仪器技术的应用系统为LAMOST光纤定位系统稳定、可靠地运行提供了保障.     

基于闭环控制的自动转位系统设计

针对某型设备自动转位系统控制及测角精度需要,采用步进电机驱动、机械机构及光栅测角细分的方法,设计了一种基于步进电机闭环控制的自动转位系统。该系统通过步进电机驱动细分和转台机械细分达到了0.5″的转位分辨率,利用光栅测角的正切法细分达到了1″的测角。实验表明：该系统控制精度达到6″,满足了系统设计精度为5″左右的要求。     

基于步进电机特性的输注设备速度最优控制

医用输注设备(输液泵、注射泵等)是一种用于自动药物注射的智能医疗器械,该设备药液输注是通过控制步进电机转动带动机械结构实现高精度的输注控制。基于电机加减速算法及驱动芯片可细分特性,设计一种根据不同的输注需求自动选择最优的加减速算法,进而通过预设转速细分表选择最优的细分值,使输注设备步进电机能够在各种应用需求场景和精度要求内平滑速度变换。实验表明本方法能够有效提升输注设备动态速度运行的效率和精度,保证了医用输注的安全可靠。     

精密电动平移台驱动系统的设计

介绍一种基于USB通信控制的精密电动平移台驱动系统的设计。该系统采用EasySmc2200型步进电机控制器,通过SH2034D型步进电机驱动器对VEXTA标准型步进电机进行控制,进而驱动电动平移台高精度的位移。电动平移台的位移通过USB接口由计算机控制。采用Visual C#编写了位移驱动控制程序,实现了电动平移台沿X、Y两轴的精密自由移动。本文描述了系统的硬件结构,详细阐述了USB通信接口设计,并给出了电动平移台驱动控制程序的流程图。实验表明,该系统位移精度满足了实验室的应用要求,现已成功应用于实验室金属缺陷检测系统中。     

步进电机矩频特性的微机辅助测试新方法

在分析常用的步进电机矩频特性测试原理的基础上，提出了一种新的测试方法，采用ＭＣＳ－８０９８单片机为下位机、ＩＢＭ兼容机为上位机构成测试系统。这种新的测试方法成功地实现了步进电机驱动系统转矩转速的自动测量和步进电机、加载装置的自动控制。与常不统相比，既简化了系统的硬件结构，又大大提高了矩频特性测试的效率、精度和自动化程度。     

基于VxWorks的三轴尾翼电机容错控制模块设计与实现

根据步进电机的工作机理以及VxWorks驱动程序的实现机制,设计了数据采集和尾翼电机控制模块,并通过编写的驱动程序实现对三轴向步进电机的控制。以工程实践中所做的嵌入式软硬件系统容错的可靠性设计为依据,硬件设计采用了结构化、模块化的设计思想;软件方面,对设备驱动可靠性的设计着重于设备驱动与操作系统内核的有效分离以及双驱动冗余备份及智能切换技术。     

动平衡机气体驱动研究

设计了一种动平衡机驱动装置,采用气体作为动力源驱动涡轮叶片转子,为测量提供稳定的转速,来确保动平衡测量的精度.阐明驱动原理和相应的结构,分析了流量与转速的关系,建立了流量与转速的数学模型,并对比分析了气体驱动与带圈驱动的转速波动和两种驱动在不同试重下不平衡量的误差.根据实验数据得出,在一定流量的范围内,气体驱动的转速波...     

基于FPGA的红外雷达寻源跟随小车

文章的设计是以FPGA的逻辑控制模块为系统核心。在对步进电机的细分驱动控制进行研究的基础上,将步进电机细分驱动应用于新的场合——红外源的搜索定位。该设计的FPGA模块中,包含了时钟预处理子模块、步进电机细分驱动子模块和信号处理子模块;该模块能够实现对雷达的转速控制,也能够分析信号接收时的外部红外源角度状态信息。在外围电路的设计上,配置了步进电机的驱动模块、红外信号接收模块和直流电机的驱动模块。整个系统能够很好地完成对红外源的搜寻和跟随。     

飞机发动机转速实时检测与仪表系统的研制

介绍一种飞机发动机转速实时检测与仪表显示系统。论述了以单片机AT89C52为核心的该系统的数据采集部分的设计思想，并对单片机和步进电机选用进行了简要论述。系统操作简便，体积小，性能稳定。主要通过对信号的采集处理与分析，由单片机对步进电机驱动控制，实现了由机械显示仪的指针变化来直观的反映转速变化的目的。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.