浅析Profibus网络的FDL

对Profibus的令牌传递与主从结合的访问机制进行了详细分析;由帧格式分析了FDL的编码效率与有效数据传输率;给出并研究了ProfibusFDL获得令牌后报文调度的四种模式调度流程;对调度模式中涉及TTR、TRR、TTH三个参数研究了它们之间的关系,这三个参数影响着报文的调度与实时应用。     

网络控制系统中网络调度算法的研究现状与展望

根据不同现场总线网络协议的特点.主要从基于优先级调度和基于表的调度两大方面对网络调度算法的研究进行分类.从优先级选取依据、调度优化以及基于表的动静态调度等方面总结了现有的网络调度算法,最后指出了还有待解决的问题.     

一种基于仿真的流程工业生产调度闭环优化方法

针对流程工业实际调度过程中存在的调度执行滞后、装置不完全利用以及生产资源浪费等问题,提出一种基于仿真的闭环调度优化方法,该方法具有多层次建模、分层调度优化及闭环校正等特点.     

约束规划在原油调度中应用的探索

石油化工是国内大型能源行业中的基础性行业,其本身是典型的流程性行业机制,在制造业中具有流程完整和全面的特性,同时在国民经济发展中起到举足轻重的重要作用。石油化工企业的工艺流程随着其炼油生产过程的扩展而逐渐的复杂化,其不同加工阶段中,对原油的调度衔接要求不同,要求原油的供应保证连续。同时整个生产过程,原油的调度不能够出现过大的波动,要保持平稳,才能实现生产设施和辅助设施的紧密连接以及调度安全。在考虑了石油化工企业的自身生产能力以及实际调度能力后,我们采用约束规划方法,进行原油总体调度的效率提升研究,实现最大限度的顺利完成生产任务、原油调度目标。     

聚氯乙烯生产过程全流程调度

研究了电石法制聚氯乙烯(PVC)全流程生产调度问题, 包括从电石生产、盐水电解到氯乙烯(VCM)聚合产品出厂各环节, 其中电石生产和VCM聚合是间歇过程, 其他生产环节是连续过程, 是一个混杂系统调度问题。本文针对过程特性对该问题进行了合理假设, 以包括电耗、库存、产品型号切换、交货延迟等的成本最小为目标, 建立了基于离散时间表示的混合整数线性规划(MILP)调度优化模型, 并针对一个案例进行了调度优化求解和分析, 验证了模型的可行性。     

纺织企业车间生产调度方法和遗传算法的研究与实现

研究了纺织公司的生产车间调度,尤其是并行成套设备多批次的调度问题,针对该调度问题进行遗传算法设计,并以示例进行仿真。使得遗传算法能在磅织企业的生产调度中起到节约生产成本,提高企业效益的作用。     

计算机控制卡车调度若干决策因素的探讨

针对卡车调度决策中存在的若干问题，分别对设备故障的影响、调度点的优化设置。分区调度等问题进行了理论分析和实例模拟研究。比较了不同设置条件下的调度效果，对系统的产量、设备利用率等指标进行了对比分析，得出了优化的设置方式。     

西部管道调度计划及热力水力工况校核的研究

针对西部管道调度计划编制和执行等方面的特点,在明确调度计划编制流程的基础上,通过强调调度计划编制的延续性以及对分输计划进行关联和组合,有效提高了调度计划编制和调整效率;通过采用水力热力耦合特征线方法对于西部管道运行过程中的水力、热力变化进行了分析和确定,为调度计划的水力热力工况校核提供了支持;引入遗传算法作为西部管道密闭流程下多泵站开泵方案的计算方法,使得调度计划的多方案比较和优化成为可能。     

基于知识的调度技术及其应用

在分析间歇过程调度问题及其求解方法的基础上，综述了基于知识的调度技术及其工业应用，并对新一代智能调度系统致力解决的问题及相应的体系结构进行了探讨。最后就中国间歇化工企业推进计划、调度与控制系统集成和开发基于知识的调度系统提出了建议。     

浅析DRS调度录音在电力系统中的应用

在电力生产和电网运行中,电力调度系统承载着极其重要的责任。调度录音系统作为电力调度的一部分,记录了电网调度命令和故障处理的过程,为事故分析提供了依据。本文分析目前调度录音系统存在的问题,详细阐述了DRS(Digital Recording System)数字录音系统的原理和架构,介绍了DRS系统的特性和优点,最后给出了录音系统运维过程的建议,旨在为通信运维人员提供些许帮助。     

多紧急等级复杂维修任务即时调度优化与应用

在油气田实际生产过程中,会出现种类繁多且紧急程度不同的维修任务,并且出现维修任务的油井分布极广。目前,维修人员的路径规划仍然依赖于人工经验,调度效率低、人员利用率低。对维修技术员进行合理安排,尽快完成各项维修任务,可以有效地保障油气田的安全平稳生产,减少因故障停机造成的经济损失。在分析实际油气田生产过程中维修任务的特点后,本文针对不同维修任务情况,提出了定时调度、临时调度、手动调度以及紧急调度四种方案。并且建立了定时调度混合整数线性规划模型、临时调度和手动调度混合整数线性规划模型,以及紧急调度模型。利用C语言编写调度软件并进行了应用验证,结果表明,所提出的调度方案可以实现对不同情况下维修任务的及时有效处理。     

Time representations and mathematical models for process scheduling problems

During the last 15 years, many mathematical models have been developed in order to solve process operation scheduling problems, using discrete or continuous-time representations. In this paper, we present a unified representation and modeling approach for process scheduling problems. Four different time representations are presented with corresponding strengthened formulations that rely on exploiting the non-overlapping graph structure of these problems through maximum cliques and bicliques. These formulations are compared, and applied to single-stage and multi-stage batch scheduling problems, as well as crude-oil operations scheduling problems. We introduce three solution methods that can be used to achieve global optimality or obtain near-optimal solutions depending on the stopping criterion used. Computational results show that the multi-operation sequencing time representation is superior to the others as it allows efficient symmetry-breaking and requires fewer priority-slots, thus leading to smaller model sizes.     

A time scale-bridging approach for integrating production scheduling and process control

In this paper, we propose a novel framework for integrating scheduling and nonlinear control of continuous processes. We introduce the time scale-bridging model (SBM) as an explicit, low-order representation of the closed-loop input–output dynamics of the process. The SBM then represents the process dynamics in a scheduling framework geared towards calculating the optimal time-varying setpoint vector for the process control system. The proposed framework accounts for process dynamics at the scheduling stage, while maintaining closed-loop stability and disturbance rejection properties via feedback control during the production cycle. Using two case studies, a CSTR and a polymerization reactor, we show that SBM-based scheduling has significant computational advantages compared to existing integrated scheduling and control formulations. Moreover, we show that the economic performance of our framework is comparable to that of existing approaches when a perfect process model is available, with the added benefit of superior robustness to plant-model mismatch.     

A general framework for process scheduling

Existing methods for process scheduling can be broadly classified as network‐based or sequential. The former are used to address problems where different batches of the same or different tasks are freely mixed or split, whereas the latter are used to address problems where batch mixing/splitting is not allowed. A framework is proposed that allows us to: (1) express scheduling problems in facilities that consist of network and sequential, as well as continuous subsystems, (2) formulate mixed‐integer programming (MIP) scheduling models for such problems, and (3) solve the resulting MIP formulations effectively. The proposed framework bridges the gap between network and sequential approaches, thereby addressing the major formulation challenge in the area of process scheduling, namely, the development of a framework that can be used to address a wide spectrum of problems. © 2010 American Institute of Chemical Engineers AIChE J, 57: 695–710, 2011     

A nested online scheduling and nonlinear model predictive control framework for multi-product continuous systems

In the pursuit of integrated scheduling and control frameworks for chemical processes, it is important to develop accurate integrated models and computational strategies such that optimal decisions can be made in a dynamic environment. In this study, a recently developed switched system formulation that integrates scheduling and control decisions is extended to closed-loop operation embedded with nonlinear model predictive control (NMPC). The resulting framework is a nested online scheduling and control loop that allows to obtain fast and accurate solutions as no model reduction is needed and no integer variables are involved in the formulations. In the outer loop, the integrated model is solved to calculate an optimal product switching sequence such that the process economics is optimized, whereas in the inner loop, an NMPC implements the scheduling decisions. The proposed scheme was tested on two multi-product continuous systems. Unexpected large disturbances and rush orders were handled effectively.     

批处理过程优化调度研究综述——2.MILP调度

详细阐述MILP建模的关键技术和现有的有关参考文献,同时给出MILP调度实施框架和已经报道的成功应用。在此基础上,指出进一步的研究方向。     

基于特定单元事件点的改进间歇生产调度模型

建立有效的间歇调度模型一直是生产调度问题调度研究的热点,而连续时间模型是优化短期间歇生产调度问题的有效工具。基于特定单元事件点的概念,建立一种改进的间歇调度连续时间混合整数线性规划(MILP)模型。该调度模型引入了新变量,使模型处理物料在不同设备间的传输过程更加灵活。结果表明,提出的改进模型只需要较少的事件点,就可以快速有效处理无限中间存储(UIS)间歇调度问题。     

改进的生物地理学优化算法在混合流水车间调度中的应用

调度问题是将有限的资源分配给各项不同任务的决策过程,其目的是优化一个或多个目标,它广泛存在于当今大多数的制造和生产系统中。混合流水车间调度问题是一般流水车间调度问题的推广,更接近实际的生产过程。采用一种新型的算法--生物地理学优化算法求解混合流水车间调度问题,通过引入改进策略,增强了算法的全局搜索能力和局部搜索能力,并提高了算法的收敛速度。通过10个标准调度算例的仿真研究,并与遗传算法进行对比,验证了改进后的生物地理学优化算法在求解混合流水车间调度问题方面的优越性。