Accelerometer drift

Hi, our team is considering making an x-drive using accelerometers that remembers and drives according to the orientation of the driver. Unfortunately, we don’t have accelerometers yet, but I wanted to know before we make an investment whether if the accelerometer drift is negligible enough to remember where the driver is oriented throughout the match, and in cases the accelerometer does become mis-calibrated during the match, if it is possible to re-calibrate the accelerometer to the driver’s orientation (after turning the robot to a set position, of course) with the vex controller.

Do you really mean the accelerometer? Would have though the gyro was more appropriate.

You would want a gyro for field centric control, as jpearman said. And if the gyro drift gets noticeably bad, just align the robot using the field perimeter and reset the gyro.

*WHEN the gyro drift gets noticeably bad

Which will be after about 20-35 seconds. They get off course so easily.

Yeah, we had the same experience earlier in the season when we built a holonomic drive with a gyro and field centric control. Turned out that the concept was a lot more of a hassle than it was worth. The drive didn’t last long either :smiley:

Our middle school team did this using Convex and programmed a couple of buttons to change back and forth between field oriented and regular control. They also had a gyro reset button as well. They are going to worlds so I guess it worked ok. Maybe they will see the thread and chime in.

I have not experienced what you seem to be describing, but we did experiment with a holonomic drive just controlled by two joystick accelerometer channels. Gotta tell you the result is not that good and the base kept going out of control.

I did mean gyro- thanks for the advice

This reset button works very well.

Just be careful of dividing by zero in those special cases where tan is infinity.

Resetting the gyro can be done a few ways

  1. Hit a wall and square yourself up
  2. Use Vamfun’s method of use the lines for fixed reference points
  3. Hit the button to reset to 0

The third is not very useful in autonomous or programming skills.