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Unread 04-10-2010, 01:56 AM
Bigcheese Bigcheese is offline
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Re: Unexpected results from Encoder::GetRate()

Quote:
Originally Posted by vamfun View Post
For some reason the encoder counts were about 1/5.7 of what they should have been... ie the avg derived rate was 1.2 fps rather than 6.8 fps. So the encoder might be broken but it did register linear GetDistance().
Aside from this, the GetRate() was consistent for 1x,2x,4x and showed plots with basically two interwoven levels. One close to the derived rate of 1.2 fps and the other around 12 fps when running max speed. So there is definitely something odd for all modes.
That's definitely not what I get. How do you get a negative value when going full forward?

Here's the data I got for a bump test I did about a week ago. The setup is really weird because we were rushing to get it before we had to leave for a week (spring break). There are two different encoders on the left and right drive trains (I don't remember which is which at the moment). We set the robot on its butt and set the jags to output 0.6, waited for 2 seconds, and then set them back to 0.

The code is set to 2x decoding and a 0.005 period (200 HZ) between every sample.

https://docs.google.com/leaf?id=0B3I...NTFjM2Iz&hl=en

Again, I don't know exactly what value should be returned, but obviously there is a difference in what our GetRate()s are returning.

I should have access to the bot tomorrow, so I'll try adding a plot of the derived rate.
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