热合装置 PLC 温度控制系统研究与开发

目的更精确地控制热合机热合装置的温度,提高热合装置压合袋口时的封口质量。方法提出了一种基于模糊自整定PID的温度控制器方案。把常规的PID控制方式同模糊控制结合起来,对PID参数进行在线修正。将常规PID和模糊PID温度控制算法在西门子PLC中编程实现,并将该方式与常规PID控制方式进行了对比。结果模糊控制方式较传统的PID控制能更稳定控制加热温度,有效提高了响应速度和控制精度。结论模糊PID温度控制系统具有更好的温度控制效果,能够提高热合装置的封口质量。     

基于PID技术的中央空调房间温度控制策略

基于PID技术实现模糊控制,考虑到中央空调房间的温度控制中,被控对象存在大滞后大惯性情况,通过设计基于Smith预估模糊自整定PID控制器技术,构建中央空调房间温度控制系统测量模型,简述预估模糊PID控制器结构,分析模糊控制规则的具体生成方法,实现对此种控制方案的数字化仿真。经本次研究结果表明:基于PID控制器技术的中央空调房间温度控制,能够有效提高对中央空调房间温度的调节精度,且调节速率较快,超调较小。     

吹膜机的模糊自整定PID温度控制系统的设计及应用

根据吹膜机温度控制系统的大滞后、非线性等特点,将常规PID控制和模糊控制相结合,设计了一种模糊自整定PID温度控制系统,该系统通过模糊控制规则实现PID控制器的参数的在线调整,以获得PID温度控制的最佳控制效果。建立了Simulink仿真模型,并对吹膜机温度控制系统的简化模型进行了仿真和分析。仿真结果表明:模糊自整定PID控制器有更小的超调量和更快的调节时间,使系统具有更好的控制性能。     

基于模糊内模-PID的包装机热封切刀温度控制

目的 包装机热封切刀温度控制系统存在非线性、大滞后性等特点,传统PID控制的效果也越来越无法满足工艺生产的要求,为了提高包装机热封切刀温度控制的速度和精度,进而提高封口的质量,以提高产品包装效率和品质。方法 在传统的PID控制的基础上,通过结合模糊控制和内模控制理论的先进控制算法,提出模糊内模-PID控制算法的包装机热封切刀温度控制系统。内模控制能够使PID控制器参数进行简化,同时模糊控制的引入能够实现控制器参数的在线调整,将该新型控制算法应用到包装机热封切刀温度控制系统中,并与传统控制进行对比。结果 通过Matlab仿真软件搭建模内模-PID控制的包装机热封切刀温度控制系统仿真平台,仿真结果表明,系统响应速度、精度、超调量、抗扰动能力等比传统控制系统性能更加优良。结论 通过仿真验证了模糊内模-PID控制在热封切刀温度控制系统上的有效性和可行性,能够在温度控制系统中表现出优良的性能指标。     

基于双模糊PID的食品包装机热封温度控制研究

目的 为提高食品包装产品的袋形质量和热封质量,提出一种提高食品包装机热封温度控制精度和稳定性的方法。方法 针对食品包装中塑料薄膜热封温度控制系统的稳定性和精确度不佳,造成包装材料过度收缩、封口不严等质量问题,设计双模糊控制器对PID参数进行在线整定,当温度偏差较大时采用模糊控制1进行粗调,以实现较快的动态响应;当温度偏差较小时采用模糊控制器2进行精调,以实现较好的稳态精度。并将双模糊PID控制器与传统PID、模糊PID控制器进行仿真对比。结果 Matlab仿真结果表明,双模糊PID控制器具有调节速度快、鲁棒性强、超调量小的优点,可以有效提升控制系的控制精度和稳定性。结论 双模糊PID控制器自适应能力强,能够克服食品包装机热封温度控制系统非线性、时变性等缺点,实现了包装机热封温度快速稳定调节。实验测试表明,将热封温度偏差控制在±1.5 ℃以内,在一定程度上提升了食品包装质量和设备自动化水平。     

基于模糊PID的电子水泵在线检测流量控制研究

目的:针对电子水泵在线检测系统工作时流量稳定时间长、稳定误差大的问题,研究一种更加高效、稳定的流量控制方式。方法:在传统PID控制方法的基础上引入模糊控制策略,设计一种实时优化PID控制的比例、积分、微分参数的模糊PID控制器;基于模糊PID控制器的设计完成了阀门开度-流量模型及传递函数的建立,以及包含参数整定的模糊PID主体设计;搭建了系统仿真模型,对比模糊PID与传统PID的仿真效果,并进行实验验证。结果:实验结果表明,模糊PID使单点流量控制稳定误差下降至±0.8%,稳定时间缩短至100 s。结论:采用模糊控制的PID调节策略能够提高电子水泵在线检测系统中流量控制的稳定性,还提高了检测效率。     

模糊神经网络锅炉温度控制系统

采用模糊神经网络和PID控制相结合的控制方式,设计了一种现代电站锅炉的温度监测系统。通过BP模糊神经网络实现对数据的模糊化处理,再通过PID控制器调节,最终实现对温度实时控制,利用Simulink软件建模,并进行电站锅炉温度监测,仿真和监测结果证明BP模糊神经网络采用梯度下降法逐层调节权值系数,实现误差均方值大幅度减小,模糊神经网络PID控制能够加快系统的运算速度,提高控制精度,获得更快的响应速度以及较小的超调量。     

基于模糊控制的HVPE生长设备温度控制系统

氢化物气相外延（hydride vapor phase epitaxy,HVPE）工艺的关键是确保加热炉的温场恒定和高精度控制。由于HVPE生长设备温度控制过程涉及多个加热温区,以及温度测量元件和电阻加热炉温度传导引起的延迟,其温度控制存在超调过大、控制精度低和调节时间过长等问题。为实现HVPE生长设备反应室内温度的精准调控,将模糊逻辑应用到PID （proportion integration differentiation,比例积分微分）控制中,设计系统各温区的模糊自适应整定PID控制器。依据实际设备与相应技术要求,设计研发了一套基于PLC （programmable logic controller,可编程逻辑控制器）、温度控制电路以及模糊自适应整定PID控制的HVPE生长设备温度控制系统。Simulink仿真结果与实测结果表明,模糊自适应整定PID控制器可以应用于HVPE生长设备的温度控制系统,且控制效果较好。研究表明,所设计的温度控制算法与温度控制系统能够很好地满足GaN材料生长的工艺要求,具有一定的实用价值。     

基于模糊PID的FDM型3D打印机喷头温度控制系统

目的提高FDM型3D打印机打印产品的精度及表面质量。方法针对FDM型3D打印机喷头温度控制具有的非线性特点,利用模糊规则对PID增量参数实时在线校正,设计基于模糊PID算法的喷头温度控制系统,并将其与传统PID控制器仿真对比。结果模糊PID控制器较传统PID控制器超调量小、达到稳定时间短、鲁棒性强,能够有效地提高温度控制系统的稳定性和控制精度。结论模糊PID控制能够提高FDM型3D打印机喷头温度控制精度,从而提高了打印产品的精度和表面质量。     

基于模糊PID的包装机热封切刀温度控制

目的为了提高包装机热合装置压合袋口的封口质量,采用模糊自适应PID控制方法对热合机热合装置的温度进行精确控制。方法针对食品包装塑料薄膜热封的温度控制,基于模糊自适应PID控制算法设计一种自动包装机热封温度控制系统。采用变论域模糊PID实现控制参数自整定和控制规则的自调整,并将其与传统PID控制进行对比。结果模糊PID控制方法较传统PID控制方法能更稳定地控制加热温度,有效提高了温度控制的响应速度和控制精度。结论该系统在热合装置中能够精确、快速地控制温度,具有应用价值。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...