Dynamic Interface Modelling and Simulation – A Unique Challenge

This paper will outline the technical challenges of dynamic interface modelling & simulation, with a specific example of the Joint Shipboard Helicopter Integration Process (JSHIP). This program, one of the most ambitious helicopter simulation programs undertaken to date, has helped both to understand the potential of rotorcraft simulation today, and to realize the limitations of technology. The benefits, such as reduced (testing and training) cost, increased safety, increased flexibility, and increased availability of the ship and aircraft, are also discussed. JSHIP is intended to allow interoperability of helicopters from the US Navy, Army and Air Force on shipboard operations. Part of this program involves the modelling and simulation of the dynamic interface between the ship environment and the helicopter. The goal of these simulations is to prove the process for determining windover-the-deck (WOD) launch and recovery envelopes using piloted flight simulation. The dynamic interface environment, particularly in the presence of wind, ship motion and low visibility can require a very high workload by the pilot. In order to validate the fidelity of this simulated dynamic interface, experimental trials have recently been conducted, and in the same way that such trials would be conducted at sea. The simulation system itself was developed by first specifying its functional requirements, and then by allocating and developing physical models of the various sub-systems. These include a Computational Fluid Dynamics (CFD) airwake model of the LHA class ship, a dynamic model of the UH-60 Black Hawk helicopter, and the simulation cueing systems. The CFD-generated WOD profile was validated during sea trials, as were several helicopter launch and recovery scenarios. The simulation trials were carried out in the NASA Ames Vertical Motion Simulator in a specially-designed cab, which features a wide-angle flatpanel display, simulated cockpit instruments, a single axis seat shaker, and an accurate representation of the flight controls.