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Unread 10-01-2008, 15:40
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Jared Russell Jared Russell is online now
Taking a year (mostly) off
FRC #0254 (The Cheesy Poofs), FRC #0341 (Miss Daisy)
Team Role: Engineer
 
Join Date: Nov 2002
Rookie Year: 2001
Location: San Francisco, CA
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Integrating accelerometer output

Hey all,

I think I want to try going with a purely inertial guidance system this year (accelerometers and gyros) instead of encoders. I don't need position information - just relative x and y velocities (along with heading).

By integrating the gyro output at about 400Hz, I get a pretty good heading calculation. It drifts by maybe a degree or two after a few minutes of driving, but that's acceptable.

My concern is with the noise handling capabilities of the accelerometer. Between the +/- 1.7G saturation of the device, nonlinearities, and possible high frequency noise, I'm having doubts about whether my integration to obtain linear velocity will be even close to accurate, even if I clean the signal up with a low pass filter.

Has anyone done this in the past? I'd like to hear your thoughts before I waste my time and end up using encoders again anyway