锅炉温度串级控制系统

介绍了锅炉温度串级控制系统的结构与控制特点，描述了应用MCGS组态软件、可编程控制器及485工控网络对锅炉夹套和锅炉内胆温度的串级控制。给出了部分PLC程序，介绍了组态软件功能窗口的设置。     

基于西门子PLC锅炉控制系统的研究

为了得到高精度的控制,PLC锅炉控制系统采用西门子S7-200PLC为核心的控制器,并运用全新电加热锅炉温度串级控制系统控制,该系统包括锅炉出口水温、炉膛的水温、加热炉的电阻丝电压等因素。运用PID算法进行系统数据优化运算,采用梯形图程序设计完成锅炉温度的优化控制,最终得到一个耗能少效率高的锅炉控制系统。     

基于西门子PLC锅炉控制系统的研究

采用西门子S7-200PLC为核心控制器,采用全新的电加热锅炉温度串级控制系统,同时运用PID算法进行系统数据优化运算,采用梯形图程序设计完成了锅炉温度的优化控制。     

串级控制在发电厂过热汽温控制系统中的应用

针对发电厂的过热汽温控制系统中锅炉过热器出口温度的非线性、时变性、滞后性等特点,提出了一种基于模糊PID控制和Smith预估控制器的串级控制器,即先用Smith预估控制器控制一级过热器的出口温度并构成副回路,然后用模糊PID控制器控制二级过热器的出口温度并构成主回路.仿真结果表明:该串级控制器有较强的鲁棒性,提高了控制系统的品质,获得了更好的控制效果.     

基于模糊自适应PID控制的锅炉过热蒸汽温度控制系统

锅炉过热蒸汽温度控制具有大惯性、纯延迟、时变性难以控制等特点,针对这种情况本文在常规PID串级控制的基础上,构成了模糊自适应PID串级控制系统,仿真对比表明该系统和常规PID控制系统相比超调量小,调节时间短,振荡周期短,平稳速度快,精度高,而且系统的静、动态特性都较好,控制效果好,自适应能力强.     

锅炉汽包水位控制系统的设计与仿真

针对锅炉在运行过程中存在的一些问题,介绍目前先进的汽包锅炉串级三冲量给水控制系统,根据串级三冲量给水控制的工作原理,设计了Simulink控制仿真系统,并在MATLAB仿真环境中对控制系统进行了模拟仿真。结果表明,三冲量串级加前馈给水控制系统可以及时消除负荷（蒸汽量）变化和给水流量波动的干扰,快速使控制水位达到稳定运行要求,具有较高的调节质量和调节精度,能够保障机组的安全稳定运行,从而延长锅炉的使用寿命。     

基于智能仪表的串级煤气加热炉温度控制系统设计

为解决煤气加热炉由于燃料压力变化而引起出料温度波动的问题,将串级技术应用到炉温控制系统中。分析了加热炉的对象特点和引起炉温波动的因素,介绍了串级技术原理,提出了基于组态软件、串级技术和智能仪表炉温液位控制系统。实验结果表明:串级技术是解决这类问题的有力工具。该控制系统具有静态精度高、自适应能力强、可靠性好、抗扰动性强的特点,大大提高了炉温的控制质量。     

基于PID参数自整定的炉温模糊串级控制系统设计

为解决煤气加热炉由于燃料压力变化和进出料时引起的炉温波动,将模糊串级控制应用到炉温控制系统中.该文分析了加热炉的对象特点和引起炉温波动的因素,介绍了参数自整定模糊PID调节原理,设计了基于组态软件、串级控制和智能仪表的炉温模糊控制系统.实验结果表明:串级控制是解决这类问题的有力工具.该控制系统具有静态精度高、自适应能力...     

串级控制系统的设计与应用

本文针对串级控制系统的原理、设计与应用进行了详细的介绍和分析,并针对连续槽反应器温度串级控制一例进行说明和Matlab仿真实验,根据两种不同的仿真波形分析得出串级控制的优点。     

液位串级变频调速控制系统的分析

以液位串级变频调速控制系统为对象,分析了当采用串级控制系统时的改善控制质量的方法。通过液位串级变频调速系统设计,介绍了液位串级变频调速控制系统的特点及相关的设计准则。详细介绍了液位串级变频调速系统中副回路的超前、快速作用。通过副回路的及时调节,可以提高主参数的控制质量。实践证明,在液位串级变频调速系统中,主、副调节器放大因数的乘积愈大,则系统的抗扰动能力越强,控制质量越好。     

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.