NavX MXP Accuracy
 

Before we buy a NavX MXP, we'd like to know the following:

Is it reasonable for us to expect that using the NavX to determine the robot's position relative to the field will remain reasonably accurate for a two and a half minute FRC round?

Re: NavX MXP Accuracy
 

When you say reletive to the field, are you referring to heading, your xy coordinates, or both? If it is just your heading I would think you'd be ok, however if you're trying to us the navX to track your xy coordinates aswell, you will most likely deal with a substantial amount of drift.

Disclaimer: I have never used the navX board, this response is purely based on what I have read others post here on chief.

Re: NavX MXP Accuracy
 

We used one positioned on to of your robot relatively centered to run our mechanum wheels in a field oriented drive. Just set up to recalibrate when the match starts we never had any issues with the rotation drifting. In my opinion plenty accurate for a 2-minute match.

Re: NavX MXP Accuracy
 

If you are referring to orientation (rotation of robot with respect to the field), absolutely yes. Hundreds of teams have used NavX-MXP for this.

Re: NavX MXP Accuracy
 

What about orientation and x,y co-ordinates?

EDIT: Never mind, I think I found my answer:
"Accelerometer data from the navX-MXP’s onboard MPU-9250 are double-integrated by the navX-MXP firmware to estimate displacement, and are accurate to approximately 1 meter of error during a 15 second period."
http://www.pdocs.kauailabs.com/navx-...ked-questions/

So it's a definite no.

Re: NavX MXP Accuracy
 

There's much discussion on chief Delphi on how to address this. It's pretty well known that there is currently no single sensor that can track position to the required accuracy for FRC. Teams are having success by a solution that fuses multiple sensors:

- wheel encoders + navX-MXP
- vision processing w/camera w/navX-MXP
- a combination of all of the above
- using a "follower wheel" that has a wheel speed encoder (for distance traveled) and an angle encoder (for current direction of travel).

Re: NavX MXP Accuracy
 

If you want absolute position over the whole duration of a match, I don't think encoder wheels will cut it this year, with all the bumps and various defenses, not without re-zero-ing repeatedly.