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Development and Redevelopment of a More Realistic Sailing Dinghy Simulator Jonathan R. Binns, Australian Maritime College, Frank W. Bethwaite, Bethwaite Design Pty Ltd, Norman R. Saunders, University of Melbourne, Mark Habgood, University of Melbourne Development of the Simulator
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Development and Redevelopment of a More Realistic Sailing Dinghy Simulator Jonathan R. Binns, Australian Maritime College, Frank W. Bethwaite, Bethwaite Design Pty Ltd, Norman R. Saunders, University of Melbourne, Mark Habgood, University of Melbourne
Development of the Simulator • Began as a “marine treadmill”, studying athletes’ performance • University of Tasmania developed a system • Virtual Sailing redesigned and rebuilt the hardware • VS1 • Virtual Sailing and the Australian Maritime College rewrote the software • VS2 • VS and AMC redesigned hardware • VS-C1
New hardware eliminated this What is the Simulator? • A “human-in-the-loop” sailing simulation
OLD Simulator Hardware VS1, VS2 • Boat in a roll frame • Pneumatic rams and pressure regulators • Transducers • Data acquisition
NEW Simulator Hardware !! VS-C1 • Cockpit/boat in a roll swing • Pneumatic ram and pressure regulators • Encoders • Data acquisition
New to old software • Cost ~$60k • Modular design allows for program to be changed • Strict separation of program elements allows development of program without secondary influences • Revisions can be backwardly compatible
New to old hardware • >$10k saving, >100 kg weight saving, <0.5 x size • Faster data rates (9.6k bps -> 33k bps, still very low) • All three transducers are the same, none require calibration ever • Lost ability to provide programmable tiller feedback
Some Simulator Uses • Entry level training • Higher level fitness and skill evaluation and sports’ specific exercise programs • Training during poor weather • Fun • “Try-before-you-buy” programs for potential buyers, leading to happier clients and selling more boats
Skills required to make a simulator • Programming – high level of efficient graphics and easy simulation • Data acquisition and control – large cost savings and speed advances possible • Mechanical design – simple tough mechanisms used throughout • Simulation – efficient and quick algorithms to provide correct dynamic feel
THE Force and Moment Balance • Essentially 4 degree of freedom (surge, sway, heel and yaw) • Done in time domain, results in F=ma, M=I, simple explicit Euler step used • Dynamics are assumed Eulerian (but should be Lagrangian!!!) • Simple force/moment decomposition with 3D vectors makes for realistic feel
Some Problems with the Old Software • Righting moment had a few bugs & did virtually nothing • No transverse force balance • Yaw moment balance had no real physical link • Rendering was quite clumsy • All drag elements were too high • meant all boat speeds were very slow
Conclusions from Upgrades • Steady state performance prediction greatly improved • Dynamic performance prediction greatly improved • Modular coding allows for many different upgrade possibilities • Hardware refinements have saved 30% off cost price and made better machine • Sailing industry has an alternative
Conclusions from Engineer’s Perspective • A yacht designer has to do everything • MUST consider technologies/methods outside naval architecture • Approximations can be massive, but usefulness of predictions can still be high • Little can be achieved with non-scientific basis
Future developments • More training tools • More multiple sail dinghies • Better dynamic prediction for apparent wind sailing
Exercise • Alter simulation parameters to make dinghy as fast as possible in 12 knots TWS • Teach someone to sail • See which boat is fastest, and think why?
