Model-based design of supervisory controllers for baggage handling systems

Abstract

The complexity of airport baggage handling systems in combination with the required high level of robustness makes designing supervisory controllers for these systems a challenging task. We show how a state of the art, formal, model-based design framework has been successfully used for model-based design of supervisory controllers for an actual industrial baggage handling system, and for a real-time emulation model of an actual international airport. The high level modeling elements of the applied CIF model-based design framework allow the modeler to concentrate on implementing the baggage handling system design requirements, instead of programming PLC code. It also allows a modular and hierarchical design of the supervisory controller, and provides flexibility in adapting and extending the model. Validation of the controller and the uncontrolled plant by means of simulation and visualization made it possible to catch all modeling errors, leading to very short modeling, testing and error correction iteration loops. To the best of our knowledge, this is the first successful employment of formal, model-based design in the context of supervisory control for actual, industrial size baggage handling systems, that covers the entire development process from requirements up to and including validation, real-time PLC code generation and implementation. We give an overview of the model-based design framework, discuss several modeling issues, and analyze the results of the industrial applications. We do not go into full technical detail, due to nondisclosure agreements, but tell the story, and give lessons learned that we consider useful for practitioners.