Subtracting centrifugal acceleration from acceleration caused by movement

  • Thread starter sparkk
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  • #1
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I've been playing around with dead reckoning stuff on an rc plane by attaching a gps, 3 axis gyroscope, and 3 axis accelerometer to the plane.

When the plane isn't turning, my algorithm works pretty well however when I enter a turn, the readings get way off. Specifically, the plane appears to be moving at a faster velocity than it actually is thus all turns are overshot.

I believe I see this due to centrifugal acceleration and would like to cancel it out, but I'm getting quite lost, especially with 3d vectors. How might I go about subtracting this observed acceleration from acceleration caused by movement?

Thank you
 

Answers and Replies

  • #2
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Let me add what I have identified so far.. for at least identifying what I believe to be the acceleration component I need to subtract:

F = ma[itex]_{c}[/itex] = (mv[itex]^{2}[/itex])/ r = mrw[itex]^{2}[/itex]

The definitions are standard as of this wiki page:
http://en.wikipedia.org/wiki/Centripetal_force

I know:
(gps) speed = v
(gyroscope) angular velocity = w

I can calculate r via:
(mv[itex]^{2}[/itex])/ r = mrw[itex]^{2}[/itex]
v[itex]^{2}[/itex]/ r = rw[itex]^{2}[/itex]
v[itex]^{2}[/itex] = r[itex]^{2}[/itex]w[itex]^{2}[/itex]
r[itex]^{2}[/itex] = v[itex]^{2}[/itex] / w[itex]^{2}[/itex]
r = [itex]\sqrt{v^{2} / w^{2}}[/itex]


With r and w known, I can now calculate [itex]a_{c}[/itex] as follows:
m[itex]a_{c}[/itex] = m[itex]rw^{2}[/itex]
[itex]a_{c}[/itex] = [itex]rw^{2}[/itex]

Am I anywhere close to being on the right track? :rofl:
 

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