Interoperability and synchronisation of distributed hardware-in-the-loop simulation for underwater robot development: issues and experiments

Development and integration of subsystems on advanced robots such as unmanned underwater vehicles, can benefit from the availability of a hardware-in-the-loop (HIL) simulation facility. Although complete interoperability of simulated and real subsystems appears desirable, substantial additional complexity of data flows and hardware can be introduced. Where nonreal time simulations are involved, methods of synchronising subsystems running at different speeds must be employed. These should take account of the realities of starting and stopping real subsystem. The paper reviews some of these issues and presents the CORESIM distributed HIL system based around HLA. The system has been used to evaluate a timeslicing synchronisation approach, and to assist in development of docking, visual servoing and concurrent mapping and localisation systems for underwater vehicles.