基于PLC的立体仓库自动取料机构设计

随着经济的快速发展,企业常常需要进行大量物料处理,并且对于货物的分拣、配送、存储等要求越来越高,具有自动取料的立体仓库因占地面积小、无需人工处理、取料快捷高效,越来越受各企业的重视.本文阐述了基于PLC的立体仓库自动取料机构设计思想,并对自动取料机构的四方面设计分别进行了介绍.     

悬吊式跨轨铁路专用门研究与设计

本文主要介绍由笔者负责设计、制造的淮南矿务局张集煤矿北区自备铁道货场一种悬吊式跨轨铁路专用门，简述该门的机构设计及主体结构、建筑设计、电气与控制设计、防雷设计、应急处理设计，介绍了该门的安全运行监督、管理措施，介绍了该门的安全使用效果和产生的显著经济、社会效益，预测了该门的广阔的推广应用前景。     

拦焦机移门机构的改进

我厂一车间共有4台拦焦机,自1990年以来相继更新为JL—1型,投入使用后故障频繁,多数发生在移门机构中。经改进后设备运行平稳,故障明显减少,收到了较好的效果。 1 原机构中存在的问题 原机构主要是移门电机功率不足,移门减速机联轴器选型不当,且设计不合理。 1.1 移门电机功率不足     

一种导光板微结构自动化加工设备

<正>本发明涉及塑料产品生产技术领域,具体公开了一种导光板微结构自动化加工设备,包括第一机架、第二机架、送料装置、夹紧机构、定位机构、加工机构及控制柜,第一机架与第二机架可拆分的连接,送料装置设置在第一机架上,第二机架顶部的工作面板上设置有门型的支撑架,     

注塑机合模机构分析及发展综述

从注塑机合模机构的功能、结构及性能特点出发,对其按照模板数目、驱动源、传动形式、合模架构等特点进行了详细分类,再选取双曲肘式、全液压直压式、无拉杆式、二板复合式4种典型的合模机构进行分析,总结出各自的结构特性及应用情况。最后又探讨了此4种典型合模结构各自的发展趋势。     

GW180-101型破碎地层取心工具研究与应用

古潜山油藏具有岩性坚硬、地层破碎、研磨性高的特点。钻井取心过程一直存在取心钻进速度慢、堵心、掉心等问题,较低的取心收获率严重制约了油气田的勘探开发。GW180-101型破碎地层工具及工艺采用高速钻头、解堵内筒、堵心报警装置、隐藏式双割心机构、井下马达驱动等技术针对性地解决潜山取心的难题。现场实验表面,该工具在提升速度、堵心判断等方面满足了破碎地层取心的要求,对提升潜山地层岩心收获率、提升潜山油藏的开发效果具有重要意义。     

橡胶件高压击穿测试装置

正本实用新型公开了一种橡胶件高压击穿测试装置,包括测试工作台、测试机构、安全开关;测试工作台包括机座、测试门、伸缩杆;测试门的两侧通过伸缩杆与机座连接,该测试门的后面具有一个触碰安全开关的触碰件,安全开关设置在机座上并对应的处于上述触碰件的下方对应位置;测试机构包括正极测试件和负极测试件,正极测试件包括一个具有多个     

化工标协西北地区企业标准化工作会议召开

中国标协化工标准化协会’98西北地区企业标准化工作会议于9月13日至16日在新疆化肥厂召开,化工标协秘书处、企工部及新疆维吾尔自治区化工厅、新疆化肥厂以及来自西北地区的20多名代表参加了会议。会议内容如下：门）介绍了原化学工业部机构改革的情况及新组建的国家石油和化学工业局机构职能分配情况。（2）传达了1998年化工企业标准化工作会议的精神,并介绍了企工部其它片区企业标准化工作开展情况。门）与会代表充分交流和畅谈了企业开展标准化工作的体会和经验。西北地区建立健全企业标准体系试点单位,太化集团公司化肥厂、甘肃刘化…     

专利文摘

具有高安全性能的夹层真空玻璃及制造方法；玻璃夹层线自动铺膜机构；用于浮法玻璃窑的粉料输送喷吹装置；超薄玻璃在线自动取片的隔层纸供给系统     

某医疗器械带金属嵌件塑件的注塑模具设计

以某医疗器械带金属嵌件塑件为研究对象,运用注塑成型技术进行注塑模具设计.针对产品的多规格及系列化特点,创新设计了浇注系统,可以根据需求成型不同规格产品.通过分析塑件的结构特征,设计了组合式型芯、哈夫机构、推出机构,实现嵌件刀片的精准定位,完成塑件成型和自动脱模.将立式注塑机工作台,由一个工位改造成两个工位,既能方便地取...     

On-line multivariable adaptive control of a binary distillation column

An experimental evaluation of the simultaneous control of top and bottom product compositions of a binary distillation column utilizing multi-variable self-tuning control algorithms is presented. The study was carried out using an 8-tray, 22.86 cm diameter methanol–water pilot scale column with continuous capacitance analysis of top product composition and bottom composition analyzed on a 3 minute cycle, by a gas chromatograph. Column control is studied for ±25% step disturbances in feed flow rate. Terminal composition regulation using both ‘positional’ and ‘incremental’ forms of a generalized minimum variance self-tuning control algorithm is compared with that achieved using a conventional digital PI/PID multiloop control strategy.     

NONLINEAR MODEL PREDICTIVE CONTROL

Nonlinear Model Predictive Control (NMPC), a strategy for constrained, feedback control of nonlinear processes, has been developed. The algorithm uses a simultaneous solution and optimization approach to determine the open-loop optimal manipulated variable trajectory at each sampling instant. Feedback is incorporated via an estimator, which uses process measurements to infer unmeasured state and disturbance values. These are used by the controller to determine the future optimal control policy. This scheme can be used to control processes described by different kinds of models, such as nonlinear ordinary differential/algebraic equations, partial differential/algebraic equations, integra-differential equations and delay equations. The advantages of the proposed NMPC scheme are demonstrated with the start-up of a non-isothermal, non-adiabatic CSTR with an irreversible, first-order reaction. The set-point corresponds to an open-loop unstable steady state. Comparisons have been made with controllers designed using (1) nonlinear variable transformations, (2) a linear controller tuned using the internal model control approach, and (3) open-loop optimal control. NMPC was able to bring the controlled variable to its set-point quickly and smoothly from a wide variety of initial conditions. Unlike the other controllers, NMPC dealt with constraints in an explicit manner without any degradation in the quality of control. NMPC also demonstrated superior performance in the presence of a moderate amount of error in the model parameters, and the process was brought to its set-point without steady-state offset.     

Two-degree-of-freedom output feedback controllers for nonlinear processes

In this work, a nonlinear output feedback control algorithm is proposed, in the spirit of model-state feedback control. The structure provides state estimates using a process model, the measured output, and the residual between the model output and the measured output. These estimates will track the process states at a rate determined by a set of tunable parameters. An algebraic transformation of the state estimates is incorporated in the control structure to ensure that the input/output gain of the observer matches the model upon which the static state feedback control law is based. The transformed states are then used in the control law. This leads to a controller of minimal order possessing integral action. The control structure is shown to have the same properties as the standard model-state feedback structure. The resulting algorithm is a two-degree of freedom control law, in the sense that the control action is not a function of the error only, but the output and the set point are processed in different ways. Finally, a simulation example using an exothermic CSTR operating at an open-loop unstable steady state is used to demonstrate the closed-loop performance of the proposed method.     

轮胎硫化生产过程的模糊控制

分析轮胎硫化生产过程的特点,建立了硫化罐温度和压力控制的多维模糊控制数学模型,设计了适合该模型的控制算法,并在实际工程中予以实现。实践表明该控制方法具有较好的鲁棒性和较好的控制效果,并具有一定的推广价值。     

粗轧控制系统的设计与应用

结合生产实际,对粗轧控制系统进行综合设计。介绍粗轧控制系统的结构,以及粗轧核心APC控制、粗轧RAWC控制和带铜SSC控制的控制思想并给出相应控制算法。     

Two-degree-of-freedom output feedback controllers for discrete-time nonlinear systems

A discrete-time, model-based output feedback control structure for nonlinear processes is developed in the present work. The structure makes use of a closed-loop observer, while at the same time it guarantees that the overall feedback controller possesses integral action. An algebraic transformation is applied on the observer states to insure that the input/output gain of the observer matches the model upon which the static state feedback control law is based. The resulting control algorithm is a two-degree-of-freedom control law, in the sense that the output and the set point are processed in different ways. The control structure is shown not only to have the same properties as the standard model-state feedback structure, but also that it emerges from a model algorithmic control framework. Finally, a simulation example using an exothermic CSTR operating at an open-loop unstable steady state is used to evaluate the closed-loop performance of the proposed method.     

MULTIVARIABLE CONTROL OF CATALYTIC CRACKING PROCESSES

Simple, explicit and physically intuitive Feedforward and Feedback control policies are designed for Fluidized Catalytic Cracking Processes. The Feedforward (FF) control algorithm compensates for changes in the feed rate and feed coking tendency by the use of the air flow and catalyst circulation rates as control variables to maintain the conversion and the reactor temperature at fixed levels. Through steady state and dynamic simulations the FF controller is shown to be very effective. To improve the dynamic response of the process and to account for the process/model mismatch a feedback (FB) controller is also designed to complement the FF action. The FB action is designed by use of the transformation related to the physical modes which correspond to the extensive variables of the process. It is shown that the required control structure consists of two loops. One uses the air flow rate to control the total sensible heat content of the reactor and regenerator solid phases. The other loop controls the regenerator enthalpy by changes in the catalyst circulation rate. The air flow rate controller includes an integral action to avoid reactor temperature offsets, while the catalyst circulation rate controller requires a nonlinear static observer to predict the coke concentration on the regenerated catalyst from dense bed and flue gas regenerator temperatures. The performance of the controller for changes on the oil feed rate, caking tendency of the feed, as well as for reactor temperature set point changes is faster and smoother than Kurihara's scheme.     

THE EFFECT OF OPERATING VARIABLES ON THE DYNAMICS OF CATALYTIC CRACKING PROCESSES

The dynamic Characteristics of a Fluidized Catalytic Cracking Process are examined over a wide range of operating conditions. A novel Order of Magnitude Approach is introduced to successfully provide physical insight into the cause and effect relationship between operating conditions and dynamic characteristics. It is shown that the original five-dimensional dynamic model is characterized by three fast time constants and two slow ones that dominate the dynamic responses. The two most important time constants are expressed as explicit functions of the operating conditions. These formulas correctly indicate in which parameter regions the open loop response is oscillatory (underdamped) or nonoscillatory (overdamped). Extensive process variables, that are either flow or capacity, related are defined in order to provide an approximate physical meaning for the dynamic modes of the system. It is shown that the two slow modes of the process are related to the enthalpy content of the regenerator and the sensible heat content of the catalyst phase in both the reactor and regenerator.     

Generic model control — A case study revisited

The application of the Generic Model Control (GMC) algorithm to the control of an evaporator has been reported recently by Lee et al. (1989). The results of their case study are claimed to demonstrate the superiority of the nonlinear GMC algorithm over conventional techniques including Dynamic Matrix Control. In this note it is shown that for the evaporator example the improved performance arises primarily from the full multivariable and feedforward nature of the control law, rather than from the nonlinear nature of GMC.     

Generic model control — A case study

This paper outlines the use of a process model directly in a control algorithm. The process considered, a forced circulation single-stage evaporator, is a nonlinear interacting process. The control strategy employing a process model derived from fundamental mass and energy balances is shown to outperform single loop and predictive control strategies by a significant amount. The control structure is first presented in general form and then specifically applied to this process.