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PowerPoint Presentation - Australian Maritime College

VIEWS: 5 PAGES: 35

									   Development and
Redevelopment of a More
 Realistic Sailing Dinghy
        Simulator
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
The old software and hardware
VS1
The New Software
VS2
New Software and Hardware
VS-C1
What is the Simulator?
 A “human-in-the-loop” sailing simulation




                                New hardware
                                eliminated this
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
The Old Simulator VS1
The New Simulator VS-C1
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
Upright Drag
                                         0.07
Drag Coefficient, Reference Area = 1.0



                                         0.06                             Original program
                                                                          Bethwaite Measured Byte
                                         0.05
                                                                          Laser
                                                                          Byte
                                         0.04
                                                                          Optimist

                                         0.03

                                         0.02

                                         0.01

                                           0
                                                0   2   4             6            8                10
                                                            Vs (knots)
Sail Lift
                         1.5

                                                                           Original SailSim Cl
                          1                                                Laser Sail
                                                                           Byte Sail
                                                                           Optimist Sail
 Sail lift coefficient




                         0.5
                                                                           Marchaj Data

                          0
                               0   20   40   60     80      100      120       140      160      180

               -0.5


                          -1

                                              Angle of attack (degrees)
               -1.5
Sail Drag
                    1.4

                    1.2

                         1
 Sail drag coefficient




                    0.8
                                                         Original SailSim Cd
                    0.6                                  Laser Sail
                                                         Byte Sail
                    0.4                                  Optimist Sail
                                                         Marchaj Data
                    0.2

                         0
                             0   20   40   60     80       100      120        140   160   180
                                            Angle of attack (degrees)
Centreboard Lift
                            1.5

                                                                         Original Daggerboard Cl
                                                                         Laser CB
                                1
                                                                         Byte CB
 Centreboard lift coefficient




                                                                         Optimist CB
                                                                         From Lewis pp306-307
                            0.5



                                0
                                     0   20   40   60     80       100      120     140      160   180

                  -0.5



                                -1
                                                    Angle of attack (degrees)
Centreboard Drag
                               1.4

                               1.2
Centreboard drag coefficient




                                1

                               0.8
                                                          Original Daggerboard Cd
                               0.6
                                                          Laser CB
                                                          Byte CB
                               0.4
                                                          Optimist CB
                                                          From Lewis pp300-301
                               0.2

                                0
                                     0   20   40   60     80       100     120      140   160   180
                                                    Angle of attack (degrees)
Polar Comparison, Old
to New program
Basic Sim Data
Extra Sim Data
The New Boats, the Optimist
The New Boats, the Byte
The New Boats, the Laser, 3 sail
options
The MegaByte, and The Liberty
(a two sail boat!!)
Polar Comparison,
New Boats
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
Simulator can be used by anyone
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?
Sailing = Glamour
take advantage, don’t get fooled

								
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