On the modeling of a capacitive angular speed measurement sensor

In the present article, a perceptive capacitive sensor for measuring angular speed of a rotating shaft is proposed. The proposed sensor is capable of measuring rotating shaft angular speed, and its changes. The proposed model’s sensing part is a suspended clamped–clamped micro-beam, which is parallel with two fixed substrates from the upper and lower sides through the micro-beam’s width surface. An electric circuit is used to give out capacitance change as a result of angular speed change, in output voltage. The micro-beam undergoes non-linear electro-static pressure that is induced due to the applied bias DC voltage. The suggested sensor has high sensitivity for a large range of working machines rotating parts angular speed measurement. The governing nonlinear partial differential equation of the transversal motion of the beam is derived and solved by step by step linearization (SSLM) and Galerkin weighted residual methods and the stable region of the sensor is determined. The effects of the applied bias voltage and geometrical properties of the micro-beam on the sensitivity and the range of the measurable angular speed of the sensor are discussed.     

Design and implementation of a low-cost multi-channel temperature measurement system for photovoltaic modules

An efficient and low-cost temperature logging system with a 16-channel input was developed for measurements of photovoltaic module temperature. This paper reports the principle of operation, design aspects, as well as the experimentation and performance of the simultaneous temperature measurement of 16 solar cells/modules. The system consists of a 16 channel multiplexer, a 12 bit A/D, a differential amplifier and NTC temperature sensors. The temperature range of the sensor is from −20 °C to 120 °C. The simplistic design requires no large internal memory to store data but incorporates a high degree of sensitivity and dynamic range (according to climate condition), thus the cost of the design remains low and makes it suitable for field applications. The system was successfully tested for the operating temperature of a 40-cell mono crystalline Si photovoltaic module under realistic outdoor conditions during a summer and a winter day. The temperature Instrumentation developed for avoidance of special interface card use enabled the successful collection of data from long distances with negligible level of noise.     

磨煤机料位测量方法回顾与展望

针对球磨机运行特性。有效监测及控制钢球磨煤机的料位,是制粉系统实现优化运行、节能降耗的关键。本文对目前磨煤机料位测量中采用的几种主要测量方式做了介绍,并对磨煤机料位的测量进行了展望。     

差压补偿液位测量的不确定度评定方法研究

对使用差压仪表进行补偿液位测量的不确定度评估方法进行了研究;建立了补偿差压液位测量的模型,分析了测量和补偿计算中的主要误差源,通过合理和保守的简化,提出了补偿后液位测量的不确定度评估方法,并对难度较大的导压管密度和工质密度引入的不确定度评估进行了深入的研究;最后,以第3代先进压水堆核电站CAP1400的大比例非能动堆芯冷却系统试验台架ACME的稳压器液位测量为例进行了应用。此不确定度评估方法可结合实际工况在各类差压补偿液位测量中广泛的推广使用。     

超声物位检测系统中的误差来源及补偿方法

本文阐述了超声波物位测量技术中影响测量精度的因素．对造成测量误差的原因——进行了分析，并且讨论了相应的补偿方法。     

混凝土储料罐料位自动测量仪

本文主要介绍基于单片机的混凝土储料罐的料位自动测量系统的组成及其部分单元电路、程序流程、工作原理等     

Design and implementation of a gain scheduling controller for a water level control system

The design of a gain-scheduled proportional plus integral (PI) controller for a nonlinear water-tank level control system is presented. A novel approach of determining operating points in terms of interpolation error is also given. The controller is implemented in LABVIEW in the laboratory. The field test results of the system response at different operating conditions clearly illustrate the controller's improved performance over a fixed PI controller.     

State of the art and future developments of measurement applications on smartphones

The modern smartphones contain different sensor technologies, so they can be used as stand-alone measurement instruments on a wide range of application domains. The paper deals with a survey of measurement applications based on smartphones. In the first part, the evolution of mobile phone technologies, including the sensors and mobile networks developments, is presented. Then, in order to highlight the sensors and the communication capabilities, the architectural overview of the hardware and software technologies, which are available on latest series of smartphones, is reported and discussed. A review of measurements applications using the smart sensors and the communication interfaces available on smartphones, it is also presented. A classification of smartphone applications, which looks the smartphone as a handheld measurement instrument, is presented. In the last part, the integration of augmented reality to the measurement applications and new type of measurement systems, having a smartphone as processing support, is presented.     

水准仪和框式方水平仪用于复杂机械设备精度测量的研发

通过太钢热连轧厂1549生产线1#卷取机夹送辊更换事例,研究和探讨了水准仪和框式方水平在复杂机械设备精度测量中的应用,为更换整体组件时如何保证设备精度提供了新的思路和方法。     

The performance characteristics of a micro-machined Coriolis flow meter: An evaluation by simulation

Micro-machined Coriolis meters will enable measurement of very low flow rates (0.1–500 g/h) and, potentially, ultra-low flows (0.1–100 mg/h). Application areas include the delivery of medical drug infusions to patients, and a wide variety of micro-fluidic devices. An evaluation of the performance of two prototype micro-machined flow-tubes of differing shapes is reported, based upon results obtained from a virtual Coriolis meter. This tool comprises a finite element modelling capability which simulates the meter flow-tube in motion, with the flow represented simply as a continuous string, i.e. 1-dimensional and frictionless, and the model allows the generation of pseudo-data at points on the tube corresponding to sensor locations. Application of signal processing algorithms then enables the representation of an indicated flow time history output by a Coriolis meter in response to a prescribed input flow. Results indicate that the devices investigated were all highly linear and that meter sensitivity is independent of fluid density. One flow-tube shape confers higher stiffness than the other and, for both tube shapes, increasing wall thickness increases tube stiffness at a greater rate than the tube mass. Higher stiffness results in reduced meter sensitivity, but increased drive frequency (hence, faster dynamic response). The spatial averaging resulting from the use of ‘distributed’ internal sensors inevitably yields meter sensitivity values that are lower than the potential maximum value that might be achieved by use of ‘point’ sensors; however there are practical reasons why this latter approach would not work. The dynamic response to a flow step is essentially the same as found for macro-Coriolis meters.     

基于MCGS/89C51的罐区多罐液位监控系统设计

针对炼厂储油罐区的多罐液位监控可靠性的需要,提出了基于MCGS组态软件的多罐液位监控系统的设计方案.系统以89C51单片机为多罐液位监控系统的主控器,用MCGS组态软件设计友好的人机对话界面,来实时监控多罐液位控制系统的运行状态.实验证明,该系统具有实际应用价值.     

A review and comparison of fault detection and diagnosis methods for squirrel-cage induction motors: State of the art

Preventing induction motors (IMs) from failure and shutdown is important to maintain functionality of many critical loads in industry and commerce. This paper provides a comprehensive review of fault detection and diagnosis (FDD) methods targeting all the four major types of faults in IMs. Popular FDD methods published up to 2010 are briefly introduced, while the focus of the review is laid on the state-of-the-art FDD techniques after 2010, i.e. in 2011–2015 and some in 2016. Different FDD methods are introduced and classified into four categories depending on their application domains, instead of on fault types like in many other reviews, to better reveal hidden connections and similarities of different FDD methods. Detailed comparisons of the reviewed papers after 2010 are given in tables for fast referring. Finally, a dedicated discussion session is provided, which presents recent developments, trends and remaining difficulties regarding to FDD of IMs, to inspire novel research ideas and new research possibilities.     

考虑处置和服务水平影响的混合系统库存决策

为确定最优的制造与再制造策略,对混合系统进行了研究。在该系统中,因再制造能力不足,返回的旧产品仅有一部分用于再制造,其余的被处置。用于再制造的旧产品构成了可翻新品库存。顾客需求恒定且由服务性产品库存来满足,该库存由制造新品与再制造品组成。顾客允许延迟交货,但企业的最大缺货量受其服务水平制约。在两类策略下分别构建了库存决策模型,即一次制造准备和至少一次再制造准备策略与至少一次制造准备和一次再制造准备策略,并利用消元思想和差分函数对模型求解,得到了最优的制造与再制造批量等求解公式。结果表明,能找到最优的制造与再制造策略,并存在一个最优的服务水平控制点。     

Comparison of a State of the Art and a High Stage Loading Rotor

July 25, 2014 / Accepted： August 18, 2014 / Published： November 25, 2014 Abstract： This paper presents the measurement results of a l1/2 stage LPT （low pressure turbine） test rig at Graz University of Technology incorporating two different rotor geometries： one with a regular blade loading and the other with a highly loaded blade geometry. The test rig was designed in cooperation with MTU Aero Engines and represented the last 1.5 stages of a commercial aero engine. Considerable efforts were put on the adjustment of all relevant model parameters （Mach number, blade count ratio, airfoil aspect ratio, blade loading, etc.） to reproduce the full scale LPT situation. The rig diameter is approximately half of that of a commercial aero engine LPT. The number of blades and vanes for the two investigated stages as well as the pressure ratio and power output are identical, resulting in a decrease in rotational speed of the HSL （high stage loading） rotor. Measurement data from a FRAPP （fast response pressure probe） is used to compare the flow fields of the two different stages. The effect of the different stage designs can be seen when comparing the exit flow fields. The highly loaded stage shows a more pronounced tip leakage vortex compared to the datum stage. The highly loaded stage shows wider wakes with a lower total pressure deficit. The fluctuations of total pressure within the flow field are directly related to the upstream wake. If the measurement position is located within a stator wake, the fluctuations are significantly smaller than that out of the wake.     

Research and development of an accurate 3D shape measurement system based on fringe projection: Model analysis and performance evaluation

In this paper, the research and development of an accurate 3D shape measurement system based on fringe projection is presented. This system utilizes a sliding projection unit to project the desired encoding fringe patterns onto the object and the object shape can be obtained by analyzing the images captured with a camera for each projection. The sliding projection unit uses a high precision grating element fabricated by electron beam lithography to produce the accurate encoding fringe patterns thus to reduce the projection error. And a method based on gray-code and phase-period edge detection is developed to align the grating element with its sliding direction to guarantee the alignment between the projected patterns. The influence of the lens distortion of both the projection unit and the camera is also studied and an improved nonlinear system model is developed based on triangulation. This model gives a more accurate mathematical representation of the shape measurement system and thus improves the system measurement accuracy. The experimental results show that an overall measurement error of 0.04 mm with a variability of ±0.035 mm can be obtained for the developed system.     

Design of a real-time overload monitoring system for bridges and roads based on structural response

The problem of the general overload of vehicles that causing premature failure of bridges and roads is becoming more and more obvious. Structural behaviors of bridges and roads need real-time monitoring and diagnosis, timely damage detection, safety evaluation and necessary precautions, in order to prevent accidents such as the crack or the collapse of bridges and roads. However, the existing monitoring system is too expensive to be applied in low budget projects. This paper designs a portable, low-cost, low-power structural monitoring system, which is equipped with Polyvinylidene Fluoride (PVDF) traffic sensors, a central processing unit (CPU), an amplifier circuit, an Analog/Digital (A/D) converter circuit, a communication circuit, an alarm circuit, and analysis software. The proposed system can collect the critical data for a certain judge algorithm about the force of the pavement. An alarm will be signaled and the overweight data will be transmitted to the data center to make further analysis. At the same time, the license plate numbers of the overweight vehicles will be collected and sent to the traffic management department. The system has been tested and the results are satisfactory. Because of its features of simple structure, easy implementation, and low cost, the proposed system fills the application gaps of structural health monitoring in low-budget projects.     

Technical note: A toy as tool: a low-cost image analysis system for the evaluation of tumor size in experimental small animal models

Image analysis systems are an essential tool in measurements of size of intraparenchymal tumors or lesions in experimental small animal models. Conventional image analysis systems are relatively expensive. We therefore compared the performance of a professional image analysis system with an inexpensive setup by evaluating tumor size in an orthotopic glioma mouse model. The maximum cross-sectional tumor area of H&E stained brain-slides of two groups of mice (treatment and control group) was measured by two independent investigators using a professional image analysis system (Leica DM IRB microscope) with the Leica Quantimet 500c software, and a low-cost-system (Intel QX3 microscope) with a non-commercial image analysis software. Mean tumor volumes were calculated and the results from each of the image analysis systems, investigators, and treatment effects were compared. The tumor volumes as measured with the low-cost and the professional system differed between -3.7 and +7.5% (P = 0.69-0.99). Measurements made by investigator A and B differed between -7.0 and +3.9% (P = 0.69-0.88). Treatment in all cases significantly reduced the tumor volume between 58.4 and 62.7% (P = 0.0002 or 0.0003), regardless of the investigator or the used image analysis system. We therefore conclude that the QX3 low-cost microscope in combination with a non-commercial image-analysis software represents an inexpensive solution to reliably analyze the size of regions of interest, if they provide a sufficient contrast. However, the low-cost setup due to its low resolution definitely limits a detailed analysis of histologic features.     

State-of-the art and development prospects of digital radiography systems for nondestructive testing,evaluation, and inspection of objects: a review

A review of modern state and practical applications of various digital radiography systems that are intended for nondestructive testing, evaluation, and inspection of objects is presented. The mainstream trends of development are described.     

低能耗变频振动下料计算机测控系统的研究

金属棒料的精密下料问题广泛存在于工业实际中,针对低能耗变频振动下料方法的特点,提出为了实现可靠、稳定和自动下料的目标,必须建立一个计算机测控系统.围绕计算机构建了测控系统的硬件结构,根据低能耗变频振动下料方法的特点开发了基于虚拟仪器LabVIEW的软件平台和人机交互界面.基于计算机测控系统实现了对LY8、20#钢和45#钢棒料的稳定下料,实验结果表明,下料效果非常理想.计算机测控系统的成功研发为进一步研究低能耗变频振动下料方法的机理奠定了坚实基础.     

Design and performance evaluation of a distribution network: a simulation approach

This paper introduces a scientific scheme for managing distribution networks to facilitate delivery of items from one place to another. It involves design of a distribution network, management of a fleet of trucks, and discussion of the roles of a distribution network. Initially, a distribution network was designed with an objective of minimizing total travelling time with the constraints of maximum truck capacity and maximum duration of travel for a single truck driver at one time. Simulation tests were then performed using SIMPROCESS to study the flow within the designed distribution network. Finally, the simulation results were used to assess the efficiency of the network, to determine the critical success factor of controlling the inventory level of packages in the distribution system, and to analyze the benefits of freight consolidation.