Problem tuning turn rate

First time in the water and this boat seems to work pretty good. Still wanted to go through all the tuning steps though. Got stumped on the turn rate. The boat’s a bit of a dog with dual Blue robotic’s 200 thrusters, no rudder and a wave-piercing hull. Adjusting the FF, P and I gains doesn’t seem to affect the pidachieved and piddesired at all. The achieved is always way behind. I’m sitting at FF 1 and P&I at .8. That’s like 4 times higher already. Any ideas?

do you have reverse enabled? if your motors are forwards only your going to have issues.

They’re not the Blue robotics esc, just a pair of old Afro 30’s flashed with Blheli firmware with reverse. So 1500 is zero throttle.

try upping MOT_STR_THR_MIX to 0.6 or 0.7, so it gives more priority to steering over throttle. Your boat looks very directionally stable, almost like 2 fins, it might just be difficult to turn it once it’s moving.

Hi, do you solve this issue?
I have a similar one, but I think it is related to how RC command is translated to desired turn rate.

I have same interrogation about these parameter (FF, P and I gains), for a boat with 2 thrusters T200 (reverse mode) it’s possible to used same process on this link: First Drive with Rover — Rover documentation ?
I’m a little lost in all these settings!
Best regards

Hi @Ludo41,

Yes, the tuning instructions for rover will also work for boats.

The tuning process instructions may be a good list to follow.

Many seem to struggle with the turn rate tuning so when you get to this stage, the key point is to get the real-time feed of desired and actual turn rate displayed on the ground station (see GCS_PID_MASK parameter) and then attempt to turn the vehicle in Acro mode and then adjust the ATC_STR_RAT_FF value until the “actual” follows the “desired” well.

There’s more to it than the above but this is the the most important part. Feel free to post onboard logs if you get stuck.

Hi @rmackay9,
Thanks for this information.
Here, when the weather is better, I will test these settings.
I’ll come back to you if I have any other questions.
Best regards

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