基于SIMATIC PCS7的带搅拌釜式反应器温度控制策略与仿真研究

该文以多功能过程与控制仿真实验系统（MPCE）中的带搅拌釜式反应器间歇反应过程为被控对象,设计了旨在确保反应温度变化的控制方案。控制方案集成了PID算法、模糊控制和专家系统。利用西门子SIMATIC PCS7过程控制系统进行了仿真研究。结果表明控制效果良好。     

连续搅拌釜式反应器的自耦比例–积分–微分控制

针对一类参数不确定的连续搅拌釜式反应器,使用了一种与被控对象无关的自耦比例–积分–微分(autocoupling proportional-integral-differential, ACPID)控制方法.该方法将系统内部所有不确定因素及外部扰动定义为一个总扰动,建立了以总扰动为激励的受控误差系统,并根据ACPID镇定规则建立了连续搅拌釜式反应器(continuous stirred tank reactor, CSTR)的ACPID控制系统.理论分析了ACPID控制系统的鲁棒稳定性和抗扰动鲁棒性.仿真结果表明了ACPID控制系统的有效性,在CSTR稳态调节控制领域具有重要的应用价值.     

非线性时滞系统的稳定自适应控制

针对模型不确定性的连续时间时滞系统，提出了一种新的神经网络自适应控制。系统的辨识模型是由神经网络和系统的已知信息组合构成，在此基础上，建立时滞系统的预测模型。基于神经网络预测模型的自适应控制器能够实现期望轨线的跟踪，理论上证明了闭环系统的稳定性。连续搅拌釜式反应器仿真结果表明了该控制方案的有效性。     

一般化学习网络及其对化学反应器的建模应用

本文研究了一般化学习网络(Universal Learning Network)在多变量连续釜式反应器(CSTR)系统的建模应用.一般化学习网络具有节点之间有多重分支、任意2个节点互连且节点之间可具有任意的时间延迟的特点,因此能够应用在高度非线性复杂系统的辨识中.分别用一般化学习网络和常规的递归神经网络对多变量连续釜式反应器(CSTR)进行系统辨识比较,仿真结果验证了一般化学习网络结构比递归神经网络Elman的辨识精度更高,且网络结构更简洁紧凑的特点.     

HOLLiAS MACS系统在山特莱德丙烯酸树脂装置中的应用

丙烯酸酯浆料/丙烯酸酯树脂生产工艺是精细化工生产中比较难于控制的装置,是比较典型的批量控制生产方式。单纯的采用某种控制模式或单个步骤采用特殊的控制设备,不利于整个项目的集中管理和优化控制。采用和利时公司的HOLLiASMACS系统对整个生产流程进行配方管理和集中控制,且运用HOLLiASMAC系统的灵活性和开放性实现了釜式反应的自动控制,提高了釜式反应的自动化程度,降低了釜式反应对各种控制软件包的依赖。从而使釜式反应的自动控制变得更加简便,节约项目的时间和成本,降低了员工的劳动强度,提高了生产效率。     

基于精确障碍罚函数的多单元极值搜索算法仿真研究

等温连续搅拌釜式反应器通常采用基于正弦激励信号的极值搜索算法进行控制,且需要针对输入流量和热能约束条件构造简单障碍惩罚函数,反应过程普遍存在着输出颤振、收敛速度慢、准确性低等问题。为此提出基于精确障碍罚函数的多单元极值搜索算法对多个相同反应器进行同步实时控制,并应用多单元极值搜索算法对连续搅拌釜式反应器进行仿真验证:该算法可有效提高收敛速度和准确性,消除了输出颤振。     

苯乙烯悬浮聚合反应器质量优化控制

聚合反应器是高分子化学工业的关键设备。此文主要研究工业规模苯乙烯悬浮聚合反应器质量优化控制问题。通过分析该间歇式反应器系统状态间内部联系,提出了两种控制方案。其一是采用自校正控制器严格控制釜温,以达到质量优化控制的目的,但对质量成分的控制是开环的。其二对产品质量是带有闭环性质的控制方案,它是针对投料失误、外部其他干扰的影响,而使第一方案无法保证反应器的质量优化控制而提出的。该方案的特点在于借助状态估计器,将反映产品质量的反应器状态反馈回输入端,利用文中介绍的优化调整算法,在线调     

基于CFD的丙烯高温氯化反应器放大研究

基于对丙烯高温氯化反应条件的研究,提出了该反应器放大的原则,确定了两种将反应器生产能力扩大至原来的1.7倍的放大方案:①反应器直径和高度都放大至原来的1.195倍,喷嘴截面积增加至1.7倍;②反应器直径放大至原来的1.306倍,高度不变,喷嘴截面积增加至1.7倍.利用计算流体力学(CFD)软件CFX5对这两种放大方案进行了模拟计算,对放大前后反应器出口氯气摩尔分率、出口温度、釜内最高温度、釜内平均温度、釜内温度和流场分布图等进行了对比分析,结果表明,高径比例不变的放大方案最好.     

基于Python的嵌入式脚本研究

嵌入脚本语言到应用程序当中在用户自动化和个性化定制方面有许多优势。介绍了Python语言,以及一种在应用程序中集成Python脚本的方法,并使用该方法实现了带搅拌釜式反应器(CSTR)自动控制系统模型中的控制单元,提高了应用程序的灵活性和扩充性。     

微机在多釜串联反应器设计计算中的应用

本文用数值方法代替 Jones 图解法进行多釜串联反应器的设计计算。其优点是简便、精确。其适用范围基本上与图解法相同,但可适用于某些变容体系。本文提供的程序还可同时计算活塞流反应器、间歇搅拌釜式反应器以及连续搅拌釜式反应器的有效容积,适于化学反应工程教学用。     

基于模糊-PID的小型反应釜控制系统设计

反应釜中进行化学反应的反应物由于浓度高、反应剧烈、控制灵敏性及散热问题比较突出,而且反应釜具有非线性、多变量、强耦合、大时滞等特点,控制任务比较复杂,用经典的PID控制很难达到理想的控制效果,本文主要对反应釜的温度控制系统进行了研究,根据反应釜的工作原理,对反应釜的过程特性和动态特性进行了计算分析,建立了反应釜的热量平衡方程,并将其线性化,推导出了冷却剂对反应釜温度的传递函数模型,采用了基于查表的模糊控制和不完全微分PID控制算法相结合的控制方法并进行仿真,结果表明,控制效果明显优于改进前的PID控制效果。     

基于SIEMENS PCS7的聚丙烯CSTR控制策略及仿真研究

针对聚丙烯连续搅拌反应过程进行了控制系统设计;该系统采用了串级控制、前馈控制、比值控制、抗积分饱和控制以及安全联锁等多种控制方法;利用西门子PCS7控制系统和多功能过程控制实验平台对系统中的各控制策略进行了验证;研究结果表明,各控制策略皆可行、有效。     

Forming processes control by means of artificial intelligence techniques

Forming processes are manufacturing processes that use force and pressure in order to modify the shape of a material part until obtaining the final product. The wide range of non-linear factors that drive this sort of processes make them very complex and extremely difficult to be controlled. Traditional control techniques, like PID controllers, have not offered a reliable solution when global control has been pursued and the figure of the operator still remains present in most of the forming facilities. On the other hand, although operators have demonstrated to be a very successful strategy when controlling this type of processes, the actual market evolution towards the fabrication of more complex parts, made of lower formability materials at higher production rates, is decreasing their capacity of reaction when solving the daily problems. Thus, the development of new global control systems based not on traditional control techniques and mathematical models but on the control strategy that has been used successfully for many years, the control through the experience and knowledge is now even more necessary. In the present work, an intelligent control system based on one of the main techniques within the artificial intelligence, expert systems, has been developed. The main purpose of this intelligent control system is to emulate the decisions that expert operators take but in a quicker and more reliable way. The developed intelligent control system has been installed in a blanking facility and very good results have been achieved.     

Development and evaluation of a Basestock-CONWIP pull production control strategy in balanced assembly systems

In this study, a new pull production control strategy called Basestock-Constant Work-in-Process (B-CONWIP) is proposed. It is used to control the flow of materials and information in balanced assembly production systems. This proposed control strategy uses one type of authorization cards called CONWIP card that limits the work-in-process (WIP) in the whole system. It has been applied in a single-product and a mixed-product assembly system balanced by two efficient Genetic algorithms introduced in literature. The performance of this control strategy is compared with another pull production control strategy called Basestock Kanban CONWIP (BK-CONWIP), which is a very promising production control strategy found in literature. The proposed strategy has two control parameters, CONWIP authorization cards and basestock levels while BK-CONWIP has three control parameters Kanban authorization cards, CONWIP authorization cards and basestock levels. The comparison is based on three performance measures average system WIP, percentage of satisfied customer demand (service level) and WIP variation between workstations. The performance of the proposed strategy B-CONWIP and BK-CONWIP is mainly similar in both types of assembly systems when mean demand rates are low with respect to mean service rates with the proposed strategy being easier to control and optimize. On the other hand, when mean demand rates are high with respect to mean service rates; B-CONWIP is preferable if service level is more important, while BK-CONWIP is preferable if WIP level is more important. Regarding WIP variation, it mainly depends on the efficiency of the balancing approach. The more efficient the balancing approach, the less WIP variation. Treating demand as lost instead of backordered results in decreased average system WIP and does not affect service levels in both PCSs. It is also shown that S-KDP is more flexible in dealing with situations of variable product mixes than d-KDP because control parameters can be used by any product which minimizes the effect of the unbalanced systems.     

基于多Agent强化学习的多站点CSPS系统的协作Look-ahead控制

研究多站点传送带给料生产加工站(Conveyor-serviced production station, CSPS)系统的最优控制问题, 其优化目标是通过合理选择每个CSPS的Look-ahead控制策略, 实现整个系统的工件处理率最大.本文首先根据多Agent系统的反应扩散思想, 对每个Agent的原始性能函数进行改进, 引入了具有扩散功能的局域信息交互项(原始项看作具有反应功能); 并运用性能势理论, 构建一种适用于平均和折扣两种性能准则的Wolf-PHC多Agent学习算法, 以求解决策时刻不同步的多站点的协作Look-ahead控制策略. 最后,论文通过仿真实验验证了该算法的有效性,学习结果表明, 通过性能函数的改进,各工作站的负载平衡性得到改善, 整个系统的工件处理率也明显提高.     

无源电子硬标签插磁控制系统设计与实现

针对目前无源电子硬标签生产过程中,通过手动插磁控制硬标签谐振频率工序存在的一些不足,设计一种自动插磁控制系统.该系统由硬标签插磁机械结构和以MSP430F149处理器为核心的控制电路及其配套控制策略组成;其控制系统基于三线圈检测硬标签谐振频率Fx的原理,采用模糊控制策略,构成一个闭环控制系统.以生产58 kHz声磁无源电子硬标签进行测试,数据分析表明:此套控制系统控制Fx精度绝对误差分别小于60 Hz,方差为0.000569,运行稳定,这为无源电子硬标签生产实现全自动化提供了技术支持.     

考虑机器故障的串行生产系统控制策略优化

针对多级串行生产系统,考虑存在机器故障和随机需求,对生产及雇佣的控制策略进行研究。以最小平均总成本为目标,建立基于（Q,r）库存策略的优化模型;鉴于求解复杂性,提出一种改进的网格自适应直接搜索算法（MADS-GA）,为避免陷入局部最优和提高收敛速度,算法中加入了停滞阻止策略;对研究实例进行求解,并与已有算法比较。结果表明,所提出的算法收敛速度和寻优能力更优,能有效优化串行生产系统的控制策略,降低平均总成本。     

Optimization of storage sizes and controls strategy in industrial production systems

The determination of optimal storage sizes and optimal control strategy for an industrial production system is treated as a stochastic feedback optimization problem. The stochastic character of the problem is due to the randomly varying production modes of the different production units of the system. The resulting average net profit during a given interval of time and under given circumstances is taken as the value of the objective function corresponding to these circumstances. The problem is then to choose the sizes of storages and the control strategy, or the control law, in an optimal way so that the value of the objective function is maximized. However, in order to make the problem realistic and the obtained results practically applicable, the choice of control strategy has to be restricted to a carefully chosen class of feasible strategies.The described method is used for solving some actual dimensioning and planning problems at a pulp and paper mill. The approximately optimal storage sizes and control strategy are found by means of computer simulation. It is found that deviations in the storage sizes from the optimal value lead necessarily to considerable yearly losses due to either production restrictions caused by too small containers or high price of oversized storages.     

制腈反应釜分段升温的多模式控制策略

提出一种制腈反应釜分段升温的多模式控制策略。针对制腈反应釜设定的升温曲线与控制要求,在反应前的预升温段采取软手操的方式达到快速升温;在过渡反应升温段采用PID调节实现平稳跟随;在决定产品质量的平稳升温段采取预测函数控制（PFC）提高控制精度。详细给出了方案设计与方案实施过程,探讨了方案切换时的波动问题。现场使用结果表明,该方案实时性好、超调小、过渡时间短,达到设计要求。     

Effect of product mix on multi-product pull control

Product mix influences the performance of pull production control strategy in multi-product manufacturing systems. The complexity of product mix on the performance of a manufacturing system is primarily based on the characteristics of the demand and production control strategies. Demands are mainly characterised by volume and product-type while production control strategy is characterised by material release time, part flow, inventory control and throughput times. In multi-product systems, pull production control strategy operates dedicated or shared Kanban allocation policy. This paper examines the performance of the Generalised Kanban Control Strategy (GKCS), Extended Kanban Control Strategy (EKCS) and Basestock Kanban-CONWIP (BK-CONWIP) control strategy operating Shared Kanban Allocation Policies (S-KAP) or Dedicated Kanban Allocation Policies (D-KAP) for a healthcare parallel/serial assembly line with setup times. A simulation based multi-objective optimisation technique was adopted to examine the effect of different product mixes on the strategies and policies. A ranking and selection technique for multiple systems was used to screen the performance of the strategies. It was shown that product mix variability in a system influence the inventory levels of the pull control strategies examined. However, the performances of the strategies vary with strategies operating S-KAP having better inventory control than strategies operating D-KAP. Similarly, BK-CONWIP outperformed its alternatives.