Compositional Methods for the Control of Concurrent Timed Discrete-Event Systems

具有越来越多的自主操作模式和多个通信组件的技术系统的出现带来了对其建模和控制的新方法的必要性，以确保其正确的行为。离散事件系统是由事件的异步发生控制的动态系统。这样的系统通常在技术上的人造系统中遇到，例如自动化运输系统、自动化制造和一般的物流。这些应用领域促进了DES监控的发展。术语“监督控制”指的是一种控制范例，其中要合成的控制器将禁用某些事件，这些事件最终可能导致不可接受的闭环系统行为，但将允许所有其他事件。对于典型目标应用的多组件结构，综合监控器控制器的主要挑战是总体状态集相对于组件数量的指数增长。这是通过组合方法来解决的，这些方法避免了显式地构建整体模型。在它们的基本形式中，DES模拟事件的顺序，这足以综合保证系统安全运行的监控器；例如，对于自动运输，一段轨道一次只能由一列列车使用，以保证安全。然而，对于许多应用程序，性能明确地与物理时间相关；例如，对于自动运输，我们关注所有可用列车和轨道实现的总体吞吐量。在这里，文献提供了在表现力上不同的多个建模框架。在范围的一端，有Brandin-Wonham框架，它使用全局滴答事件来表示时间的流逝，还有时间事件图(TEG)，这是一种特定类型的Petri网，可以转换为线性(max，+)方程。对于这两个框架，控制器综合都是很好理解的。然而，这两个框架在表现力方面都处于低端，存在严重的局限性，使用Brandin-Wonham无法对具有多个实时时钟的并发系统进行建模，而TEG无法解决逻辑决策问题。在这个研究项目中，我们将建立有效的方法来控制定时DES，这些方法比Brandin-Wonham框架和TEG更具表现力。从技术上讲，我们将以所谓的(max，+)自动机和特定类型的赋时Petri网作为基本模型，以开发模块化和层次化的监控方法，包括各自的合成算法。我们的结果将极大地扩大DES的基于模型的控制器综合的范围。

The emergence of technological systems with more and more autonomous modes of operation and several communicating components brought the necessity of new approaches to their modeling and control in order to guarantee their correct behavior. Discrete-Event Systems are dynamical systems governed by asynchronous occurrences of events. Such systems are typically encountered in technological man made systems, such as automated transport systems, automated manufacturing, and logistics in general. These application areas have stimulated the development of supervisory control of DES. The term "supervisory Control" points to a control paradigm where the controller to be synthesized will disable certain events that may eventually lead to an unacceptable closed loop behavior, but will allow all other events. Referring to the multi-component structure of the typical target application, the main challenge in the synthesis of a supervisorycontroller is the exponential growth of the overall state set in terms of the number of components. This is addressed by compositional methods which avoid the explicit construction of an overall model. In their basic form, DES model the order of events and this is adequate to synthesise supervisor that guarantees safe operation of the system; e.g. for automated transport, a segment of a track shall only be used by one train at a time to be safe. However, for many applications performance explicitly relates to physical time; e.g. for automated transport, we are concerned about the overall throughput realised with all available trains and tracks. Here, the literature provides multiple modelling frameworks which differ in expressiveness. On the one end of the range, there are the Brandin-Wonham framework, which uses a global tick-event to represent the elapse of time, and there are timed events graphs (TEG), which are a specific type of Petri nets that translate to linear (max, +)-equations. For both frameworks, controller synthesis is well understood. However, being on the low end regarding expressiveness, both frameworks have severe limitations.With Brandin-Wonham, one cannot model concurrent system with multiple real-time clocks, and TEG cannot address logical decision making. In this research project, we will establish efficient methods for the control of timed DES that are more expressive than the Brandin-Wonham framework and TEG. Technically, we will consider so called (max, +)-automata and specific classes of timed Petri nets as base models, in order to develop modular and hierarchical approaches to supervisory control, including the respective synthesis algorithms. Our results will considerably enlarge the scope for model based controller synthesis of DES.