Time- and Behavior-Preserving Execution of Determinate Supervisory Control

TL;DR

This paper introduces an execution architecture and engine for the activity framework in FMS, enabling automatic, time- and behavior-preserving implementation of supervisory controllers, validated on a prototype system.

Contribution

It transforms the manual supervisory control implementation into a model-driven approach with proven preservation of timing and behavior.

Findings

Preserves specified action and event orderings.

Maintains timing constraints within a defined bound.

Validated on a prototype production system.

Abstract

The activity framework is a promising model-based design approach for Flexible Manufacturing Systems (FMS). It is used in industry for specification and analysis of FMS. It provides an intuitive specification language with a hierarchical view of the system's actions and events, activities built from them, and an automaton that captures the overall behavior of the system in terms of sequences of activities corresponding to its accepted words. It also provides a scalable timing analysis method using max-plus linear systems theory. The framework currently requires manual implementation of the supervisory controller that governs the system behavior. This is labor-intensive and error-prone. In this article, we turn the framework into a model-driven approach by introducing an execution architecture and execution engine that allow a specification to be executed in a time- and behavior-preserving fashion. We prove that the architecture and engine preserve the specified ordering of actions and events in the specification as well as the timing thereof up to a specified bound. We validate our approach on a prototype production system.