CASE MAXXUM Can Bus steering issues

I was using AOG well with my previous tractor (JD6620) with phidget motor. RTK base station at home.
I changed tractor and now have a CASE MAXXUM 125 autosteer ready.
I built Tony’s board with Teensy and connected everything well to both can busses on the case. Set up in service manager for Case. AOG 5.7.1, latest ino from tony’s github. UDP without router
I can get all infos from tractor : hitch height, wheel angles, autosteer button for activation, … It’s integrated in the tractor as an official commercial system which is really great !

But…, I can’t get it to follow the line.
When starting on the line (AB straight) it’s making wider and wider S around the line.
It overshoots and then corrects sharply to the other side, then overshoots and corrects sharper, …
It should turn wheels the other way when getting to the line but it keeps crossing the line and correct too late.

AOG 5.7.1 :
PP, Acquire look ahead : 20, hold look ahead 2.4, look ahead speed gain 1.2, integral 15
Motor : proportional gain 25, max limit 164, minimum to move 5
Rtk fix, WAS zero adjusted, counts per degree as well. Tried with Ackerman 100 and adjusted to 84
All tractor and antenna parameters are set. Antenna on the front hood; rtk fix.

Tried with 5.6.15 which is working for Emmanuel, with his adjustments and all the same, not working for me.

When adjusting manually wheel angle, it’s fast, precise and reapetable.
tried to adjust PP values but still not good…

Looking at curves, bothe curves are very close. It looks like tractor is following precisely the target angle but target angle looks sleeping…

I don’t know what else to check or to adjust, has someone an idea ?

Thanks for your help


Hi Julien,
you should look after the counts per degree, in my case (Massey Ferguson) the wheel angle was not correct causing overshoot. I drive with stanley. Works good so far.

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I have the feeling counts per degrees are correct.
I used the « record » function to measure the real angle and set the cpd to match the real angle.
I did it the other side and adjusted the Ackerman to come again to the correct wheel angle between measured and displayed on AOG.