Скачать или смотреть Motion Talk 9 | Degrees of Freedom Tradeoffs & Expectation

Quick motion talk, discussing the various DOF's or degrees of freedom that are represented in motion. The 3 principle DOF's are Pitch, Roll and Heave, and the additional lateral DOF's of Surge, Sway and Yaw (also called traction loss).

Heave is probably the best at representing the true nature of the vehicle in the simulation, as the vector or direction of motion, matches the rig in real life. Often just limited by acceleration for health and safety reasons.

Pitch and Roll can be used to simulate the movement of the vehicle relative to the track or the position of the vehicle relative to the environment (true Pitch and Roll) However, more often than not, pitch and roll are also used to represent sustained lateral G's. This effect may work to trick the brain to some small extent but the approach also has inherent limitations and even negative implications of affecting the accuracy of driver input when pitching or rolling the driver to extremes.

Surge, Sway and Yaw are further limited, in the sense that what most people believe they will get is a sustained feel of traction loss or sustained G's. But in affect just get the very brief change of direction before a feature called Motion Cueing has to rein in the motion and prepare the simulator for the next potential motion direction. The big tease!

In short, the 3 principle DOF's of Pitch, Roll and Heave... which get you most of the way in simulating vehicle or craft dynamics. But Surge, Sway and Yaw are much more difficult and have a much larger diminishing returns. Or in other words, for the cost, complexity and size of a 6-DOF simulator, you get a lot less than with a well tuned 3-DOF setup.

This of course is arguable from both sides but we cannot ignore the constraints of the world (physics).

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