What is hlacerti?

Work surrounding High-level Architecture

hlacerti is a co-simulation framework that leverages two open source tools: Ptolemy II and CERTI. CERTI is compliant with the IEEE High-Level Architecture (HLA) standard for distributed discrete event simulation.

HLA defines a federation as a distributed simulation grouping several federates connected via the Run-Time Infrastructure RTI. The standard is responsible for a coherent time advancing in the federation.

When using the hlacerti framework, a federate is a Ptolemy model extended with the addition of three components: HlaManager, HlaPublisher and HlaSubscriber. The top level model has a DE director that can have composite actors with Continuous Director.

The DE director ask the services of HLA for advancing the time of a Ptolemy model. The decorator HlaManager decorates the time advancing in Ptolemy using HLA time management.

The HlaPublisher actor provides three information to the HlaManager: Publish an object class (HLA service publishObjectClass()), Register an object (HLA service registerObjectInstance()) and update values of a class attribute (HLA service updateAttributeValues() or UAV).

The HlaSubscriber actor provides three information to the HlaManager: Subscribe an object attribute (HLA service subscribeObjectClassAttribute()), Discover an object (HLA service discoverObjectInstance()) and receive (updated) values of a class attribute (HLA service reflectAttributeValues() or RAV).

The design of a Ptolemy federation from a (centralized) Ptolemy model is straightforward (see the User Manual for HLA-PTII Federates).