I’m currently seeding sugar beets. My seeder is a 12 rows, 45cm spacing. So ideally, between 2 pass, the space shall be 45cm. But, as AOG is driving with +/-2cm accuracy, between 2 pass, I shall measure 45cm +/-4cm.
I’have seed in a flat field, around 1° or 2° of tilt. If I disable the roll in AOG, everything works perfectly. Between 2 pass, I always measure 45cm +/-4cm.
But if I enable the roll, it doesn’t work at all: between 2 pass, I’m always under 43cm, more often at 40cm and sometime less.
It’s not a autosteer problem: on AOG I’m on the line. But the line “is not correctly positionned” compare to real world.
To illustrated, some pictures, with roll enable:
- On AOG, I’m on the line:
- In real world, the tractor is shited from the seed drill plotter (in this case space between this space and the previous was less than 40cm):
If I disable the roll, everything go back to normal work: when I’m on the line in AOG, I’m align with the seed drill ploter. Space between 2 pass is 45cm.
So it’s look’s like when the roll in enable “the line in AOG is not in the correct place in the real world”.
So correct me if I’m wrong: in fact in AOG the line is always at the same place (every 5,4m in my case): it’s the mesured GPS position that is corrected by the roll value.
A schematic of a tractor on a side hill:
- The tractor real position is point A
- The GPS position mesured by GPS du to hill is point B
So mesured GPS position shall be corrected from the distance L between point A and B. L is calculated with tilt measurement angle alpha. Then when we know L, we can corrected tractor measured position B to obtain real tractor position A.
So in my case it’s look like the tilt compensation calculation: tilt is overcompensated.
But I have checked 10 times:
- Antena height correctly configure in AOG
- IMU zeroed on flat surface
- All other tractor dimentions
- All tools parameters also: but as it work without roll, it’s confirm that it’s correctly configured
So for now, roll is disable, the first part of the field I’m working in as a little tilt: 1-2°. So the error du to tilt seems negligible: positionning of the tractor in real world is bette without roll.
But the tilt of the field is going to increase, I things to 5-6°. Not neglitible, so I will have to enable the roll.
So anyone have an idea of what’s going wrong when I enable the roll ? Does I miss something ?
Thank for your help.