What Is msmac3D Coordinate Sign Convention?

Question on 3D Simulation/msmac3D/HVOSM and other 3D Simulation models
MSI
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What Is msmac3D Coordinate Sign Convention?

Post by MSI »

The Coordinate Sign Convention for Vehicle Dynamics as follows:
  • X forward,
  • Y to the right,
  • Z down (towards the earth as in Positive Gravity)
The msmac3D, HVOSM and SMAC programs ALL use the same conventions.
When HVOSM was first developed in the late 60s space travel was on the rise so they wanted a general purpose program that could simulate in near zero gravity (HVOSM & msmac3D can still do that! since Gravity is an optional input)
So Raymond R McHenry used flight conventions for the simulation coordinate system.
Flight conventions:
Flight coordinate conventions.jpg
Flight coordinate conventions.jpg (25.72 KiB) Viewed 20305 times
  • This was from book Dynamics of flight, originally published in 1959 and used by Ray McHenry in his graduate studies at the Chrysler Institute of Engineering and then in the formulation for HVOSM, SMAC etc.
    The sign convention also adopted by SAE in 1994 as sign convention for Sign Convention for Vehicle Crash Testing J1733_201811
    Sign Conventions.png
    Sign Conventions.png (113.06 KiB) Viewed 17808 times
    Here is the HVOSM Coordinates:
    HVOSM Coordinates.jpg
    HVOSM Coordinates.jpg (36.89 KiB) Viewed 20305 times
    NOTE: Some simulation programs use Cartesian Coordinates.
    • Like the screen you are reading this on.
      • X goes + across to right,
      • Y goes + UP, and
      • Z goes + coming out at you.
      Cartesian Coordinates.jpg
      Cartesian Coordinates.jpg (11.17 KiB) Viewed 20305 times

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