Integration of Object-Oriented Methodologies, Petri Nets and Software Architectures for Distributed Control of Engineering Systems

本研究计划将发展一套全面而系统的方法来解决工程系统的建模、仿真与控制问题。该问题的理论方面，以及与分布式计算环境中模拟和控制算法的软件实现相关的问题将被检查。流经系统的实体及其通过各种系统流程进行的转换将通过面向对象的表示进行建模。因此，系统输入和输出将被视为具有属性、方法和到其他对象的链接的对象。系统流动力学，即支持的实体流的结构及其相关的事件时间将使用随机Petri网的形式进行建模。这种正式的建模框架将提供足够的建模能力，以协助分析系统中的实时流动动力学，即使在存在不确定性的情况下。它还将为最终综合有关控制政策提供获得新的理论见解的基础。特别是，研究主题将是结构控制领域的现有结果转移到这个新的建模框架的背景下，结构和面向性能的控制的相互作用，在结构控制对象系统的背景下对现有排序和调度策略的性能进行系统评估，以及产品质量与系统吞吐量和生产率之间的相互作用。在通过这些研究获得的理论见解的基础上，将制定用于工程系统仿真和控制的新算法，并开发这些算法的分布式软件实现。“通过这种方法获得的结果将在乔治亚理工学院制造研究中心的表面贴装印刷电路板装配线上得到验证。”

This research project will develop a comprehensive and systematic approach to the problem of engineering system modeling, simulation and control. Both the theoretical aspects of the problem, and the issues related to software implementation of simulation and control algorithms in a distributed computing environment will be examined.Entities flowing through the system and their transformations by the various system processes will be modeled by object-oriented representations. Thus system inputs and outputs will be treated as objects having attributes, methods, and links to other objects. The system flow dynamics, i.e., the structure of the supported entity flows and their associated event timings will be modeled using the formalism of stochastic Petri nets. This formal modeling framework will provide adequate modeling capability to assist in the analysis of the real-time flow dynamics in the system, even in the presence of uncertainty. It will also provide the basis for gaining new theoretical insights for the eventual synthesis of pertinent control policies. In particular, topics of investigation will be the transfer of existing results in the area of structural control to the context of this new modeling framework, the interaction of structural and performance-oriented control, the systematic evaluation of the performance of existing sequencing and scheduling policies in the context of structurally controlled object systems, and the interaction between product quality and system throughput and productivity.On the basis of the theoretical insights gained through these investigations, new algorithms for the simulation and control of engineering systems will be formulated, and distributed software implementations of those algorithms will be developed. 'The results obtained through this approach will be validated by their application to a surface-mount printed circuit board assembly line located in the Manufacturing Research Center at Georgia Tech.