可重构制造系统监督控制器的自动重构

提出了基于改进的网重写系统(Improved net rewriting system, INRS)的可重构制造系统(Reconfigurable manufacturing systems, RMS) Petri网监督控制器的自动重构方法, 以快速适应由市场需求变化所引起的制造系统构形的频繁变化. INRS解决了网重写系统存在的问题, 可动态调整给定Petri网模型的结构而不改变其行为属性. 以集合和图的组合形式定义了RMS的构形, 并提出了基于INRS的一类模块化、可重构的Petri网控制器的设计方法. 针对这类Petri网控制器, 提出了基于INRS的自动重构方法. 方法可将RMS构形的变化转变为INRS的图重写规则, 并作用于当前Petri网控制器, 使其快速、自动地重构为所求的新控制器. 所提出的Petri网控制器的设计与重构方法, 均从理论上保证了结果的正确性, 免校验. 仿真研究验证了方法的有效性.

Automatic Reconfiguration of Supervisory Controllers for Reconfigurable Manufacturing Systems

This paper presents an improved net rewriting system (INRS) -- based method for automatic reconfiguration of Petri net (PN) supervisory controllers for reconfigurable manufacturing systems (RMS) to adapt rapidly to frequent changes in the manufacturing system configurations driven by market changes. INRS addresses the problems of net rewriting systems and can dynamically change the structure of a PN model with preserving its original behavioral properties. An RMS configuration is formally defined by incorporating the formalisms of set and graph. A design method for a class of modular and reconfigurable PN controllers is presented with an approach of INRS. Subsequently, an INRS-based method for automatic reconfiguration of this class of PN controllers is proposed. Using the reconfiguration method, changes in an RMS configuration can be automatically transformed into graph rewriting rules of INRS; by applying the rules to the existing controller, it will be reconfigured into the needed one. The resultant PN controllers obtained by both the design and reconfiguration methods are guaranteed to be valid in theory, without the need of verification. Simulation results show the validity of the presented methods.