Skidsteer Pivot turn more power needed - SOLVED

My skidsteer rover pivot turns fine in manual mode, but as soon as I switch it to Auto, it will sit still in the soft lawn with torque applied but not enough torque to initiate the turn. If I flip it to manual and get it moving I can flip to auto and it will go.

I saw an old post from 2017 that power is limited to 50% on pivot turns.

Has this been fixed to make it a configurable parameter?

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I’m facing the same issue with my Pixhawk 4 setup. Any help will be appreciated!

I brief look through present source code does not turn up any output limitation (though I admit, I only searched briefly). I have not heard of such a limitation, and I suspect this is old/outdated information.

To increase the steering controller’s output, ensure that ATC_STR_RAT_MAX is set to a value that is achievable by your Rover (90-180°/sec is likely within reach unless you have a very slow wheel speed).

Tune the steering per the wiki guide(s). Ensure that ATC_STR_RAT_FF is set high enough to control your Rover.

Move on to tuning ATC_STR_ANG_P via the wiki instructions, thereafter. If the previous step resulted in success, and you can control the Rover in ACRO mode, this step should be successful.

It is NEVER recommended to simply get things working in MANUAL mode and then leap to AUTO mode with an expectation that it will respond predictably.

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Thanks @Yuri_Rage, I will look into tuning. It just seems wrong that an ultimate power/torque would be affected by rate/acceleration parameters.

It isn’t. But if you haven’t tuned the controller, it doesn’t “know” how to get there, and there is no reasonable expectation that AUTO mode will work.

This required a bit of study. I have tuned PID systems before, but usually temperature related which usually operate at max gain (either full on or full off, so no FeedForward). I had misunderstood what the FeedForward parameter is, as the tuning guide says to increase FF if it is “sluggish”. Well, my bot wasn’t sluggish, it moved quickly once it got going, so I had been just tuning the P and I.
Turns out FeedForward is a primary gain that tells the system how hard to push even before any FeedBack provides correction. I ended up having to retune my Odrive motor controller first but anyway, bumping ATC_STR_RAT_FF from 0.2 > 1.5 resolved the lack of turning power.