Autotune

guilhermito edited this page May 15, 2013 · 2 revisions

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Using Autotuning

Autotune is an exciting new feature being developed for TauLabs, the idea is the craft will perform a calibration routine and try to come up with sane stability values without any user configuration.

When this module is complete you will be able to drastically reconfigure your airframe in the field and perform an autotune on the spot to give you a solid flying platform without manually trying to retune values for optimal performance.

Warning

This is an experimental plugin for the GCS that is going to make your aircraft shake, etc, so test with lots of space and be very very wary for it creating bad tuning values.

Basically there is no reason to think this will work at all. Currently this feature is intended for Multirotor Aircraft ONLY!

Perform this operation in an open and safe environment, the aircraft is likely to gain altitude when the test starts and shed altitude when it ends.

Setup

To use autotuning, here are the steps:

Enable Autotune

  • On the GCS Configuration page, select the Autotune section.
  • In the Autotune section, select the Pre-Autotune tab and check the “Enable Autotune Module” box.
  • Click “Save”.
  • Power cycle your board, disconnect both battery & USB!

Add Autotune to the Flight Mode switch

  • On the GCS Configuration page, select the Input section.
  • In the Input section, select the Flight Mode Switch Settings tab.
  • Set one of the Flight Mode Switch Positions settings to Autotune in the pull-down menu.
  • Click “Save”

Autotune

  • Before you start Autotune, make a note of your current PID settings, you'll need these settings to compare them with the calculated values. Note that you need the advanced settings of the Stabilization to compare them with the Autotune computed values.
  • Take off normally and hover
  • Activate Autotune by moving Flight Mode switch into the selected position.
  • The craft will gain altitude and begin to oscillate. Each axis takes approximately 30 seconds to calibrate, so expect this oscillation behavior to last around 60 seconds.
  • Use your normal control inputs to maintain a hover in the general area, but try to minimize control inputs to the degree this is practical.. The craft will stop oscillating and descend when Autotune cycle is complete. ** If you have no control of the multirotor with your transmitter during the Autotune process, that means Autotune is not properly enabled in the GCS.
    Change flight modes, land and verify your settings again.
  • With the craft still in Autotune mode, land the aircraft normally and disarm the OP board, but leave the aircraft powered. If you leave the Autotune mode or If you unplug the battery now you’ll lose the Autotune settings you’ve just created.

Verify and store the settings

  • Connect the OP board to the GCS
  • On the Configuration page, select the Autotune section.
  • Look at the “Computed Values” and compare them to your previous PID settings. ** Autotune tends to compute higher values for the Integral part of the PID controller which is normal.
  • If the computed values are vastly different than the settings you were previously using, only use these new settings with caution.
  • If you want to save the settings generated with Autotune to the board, click the “Apply Computed Values” button.
  • Click the “Save” button.

Disable Autotune

  • Disable Autotune by selecting the Pre-Autotune tab and unchecking the “Enable Autotune Module” box.
  • Click the “Save” button.
  • Remove Autotune from your Flight Mode switch.
  • Test fly your craft with the Autotune settings to determine their suitability.

Settings

  • Hysteresis setting: Defaults to 5 deg/s. Hysteresis is sort of like de-noising and should make it more noise-robust.
  • Output step from 15% of the output range to 25%.
  • The Step Size is the size of the oscillation it generates. In principle large should give more accurate results. We don't want the step size much above 25% ideally since that's going to be some pretty serious swings.

The settings can be verified in the UAVObject browser under RelayTuningSettings