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Image showing Ackermann steering where all of the projected wheel axles meet at the center of rotation

Source: https://en.wikipedia.org/wiki/Ackermann_steering_geometry

The image above shows a vehicle with Ackermann steering. The front wheels are connected by a mechanism so that they turn at different angles such that the projected axles of the wheels meet at the same point, the center of rotation.

Image showing non-Ackerman steering where the projected wheel axles do not all meet at the same location

Source: https://www.google.com/patents/US6634109

This image shows a case where are four wheels do not have the same center of rotation.

If the Ackerman condition is not satisfied as shown in the figure for a car taking a turn, then what would be the equivalent centre of rotation for the vehicle?

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    $\begingroup$ Could you elaborate your question to make it more understandable? You drew the 4 wheels of a car and what are the other lines? $\endgroup$ – Karlo Apr 3 '17 at 8:26
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    $\begingroup$ @Karlo It's perfectly clear to me. Relates to vehicle dynamics, which should probably be added as a tag. en.wikipedia.org/wiki/Ackermann_steering_geometry $\endgroup$ – DLS3141 Apr 3 '17 at 20:33
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    $\begingroup$ Why is this question on hold? The question is clearly about what happens to the center of rotation when a vehicle does not have an Ackermann steering setup (like we have in all modern cars). The diagram could certainly be improved but the question is clear and answerable. $\endgroup$ – ConjuringFrictionForces Apr 5 '17 at 1:58
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This is quite easy:

  • Choose one of the wheels
  • build a second wheel so it would satisfy Ackerman condition
  • Get the First rotation point ( O1 )
  • Do the same with the second wheel, and get a second rotation point ( O1' )

The actual rotation point can be anything between these two points.

If you choose, for instance, the first point as rotation point, it means that the first wheel has no issue but the second wheel therefore has an additional damping to its movement.

To find the real rotation center you could compute including the damping on each wheel, but In a driving situation equal damping is quite unlikely, more over it can change in function of the directions. On top of this, this Damping changes in function of the object dynamics. So you may most likely end up with an irrelevant model.

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