Prop Shield Angular Velocity

[drichelson]

I'm working on a project using a Teensy 3.2 + Prop Shield. It will be mounted on a wheel and I'd like to read angular velocity. I see some references in the code: https://github.com/PaulStoffregen/NXPMotionSense/search?utf8=✓&q=angular but it's not clear how to get the angular velocity. Any help/examples are appreciated.
Thanks

 

[onehorse]

Gyros output rotation as degrees per second. 360 degrees per circumference, 360 x 2 x radius of wheel = length traveled in one revolution. So easy to translate between degrees per second to length per second.

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[drichelson]

Yes! Thanks for the quick reply.

 

[expiomegat]

Dont you need to covert to radians per second first?

X deg/sec * pi rad/180 deg * radius = length/sec

Also op your angular velocity is deg/sec (it is the rate of rotation). Your linear velocity is from the above eqn and corresponds to how fast the center of a wheel of radius r translates when it rolls on the ground with angular velocity x

 

[PaulStoffregen]

The raw gryoscope data already is degrees per second.

Usually the raw data from the gyro, accelerometer, and magnetometer are fed into a filter algorithm. The filter's output is improved orientation data, which can be in radians/sec or degrees/sec, or quaternions.

 

[expiomegat]

The raw gryoscope data already is degrees per second.

Paul - Not sure if that was directed at me or OP, but just wanted to clarify I meant if you have deg per sec and you want length per second of a wheel, you have to convert the deg per sec to rad per sec before you multiply by the radius. I was just correcting the post above me which I think incorrectly stated deg per sec * radius = length per sec. It think it should be deg per sec * (pi/180.0) * radius = length per second

I agree with the filter comment though, I think kalman filters are popular for this kind of application? Or an iir for frequency content isn't too hard to implement