Calibration / Configuration issue

[ThomasT]

Hi World,

Did made an Standard Board V4.5, Phidget motor, Land rover WAS sensor, single ardusimple GNSS antenna, BNO085 imu.

The board is mounted inside the cabin on the right, Y+ Axis configured for the IMU, the antenna is centered with the tractor width and just a bit off in the back with the pivot / axle point.

WAS 0° is good, tractor driving straight while keeping the wheel 0° but I have to find a way to set/calibrate/measure accurately the angle at 45° for example, for the moment I configured it from what I guess it actually is.
Roll was done on a concrete slab but have to find one thats completely level, shouldn’t be far off tho.

When experimenting tractor driving in the field I had to revert the IMU / GPS fusion % (so 40 - 60 instead of 60 - 40) for the tractor to pass on the same line from each direction.
Did set a straigth guideline, stopped, set a reference.
Coming in the same direction I had a gap of 0.5cm.
Coming in the reverse direction I had 8 & 12cm gap. Those error/offset margin are enough for me.

Then the next step was testing it at work, after it rained nicely I did a pass of covercrop / disks on wheat fields.
The tool has an offset of 10cm on the right.
The tool is dragging the tractor on the right side a bit.

The worked area seems straight tho but the tractor stay between 40 to 60 cm offset to the guideline (showed on the software). The speed does impact the offset, with more speed it would go more away from the guideline.
So the software does know it is off but don’t steer or compensate enough to be on the line.

U-Turn is working too, with 7 raw skip as the tool width is small. Only doing 1 or 2 zigzag at the beginning when it take the guideline, I believe it could be due to the wheel angle not being the real one.
All lines that where took in the same direction did cover themself correctly but at the jonction of the “up” & “down” row it leaved a ~1m gap which concord with the 40 to 60cm error on the software.

My question is, why can’t it compensate more to go back on the line ? Is it the PID ?
I can guess the combination off approximative WAS angle & roll that may not be 100% level does also impact it a bit.

Would appreciate any insight from experimented users.

Have a nice day,
Thomas.

[cowhound]

If all your tractor dimensions are entered right it sounds like the was 0 is not correct. Go to the steering settings window and adjust the was 0 while you have it following a line and see if that helps.

The roll being off will show the tractor driving in the right place on screen but it won’t be in real life.

If this doesn’t help you might post your settings and maybe someone will see something odd.

[del_boy]

To set the was0 autosteer on a ab line and move the was0 slider the opposite way to which your xte is. Keep adjusting the was0 until you get xte flicking both sides of the line the same amount
Doing the steer wizzard should get your steer settings pretty much in the right ball park to start with then a bit of fine tuning afterwards

[ThomasT]

Will to adjust the WAS without a tool (no more fields to work on) when I can but whithout the dragging effect the tractor is being on the line much better.
With the discs, I tried taking a higher speed but the error went higher too, so I stayed in the same speed range as I started with to keep the same eror spacing everywhere.

240 cm wheelbase
160 cm track width, is it front or rear wheel base ? The rear is a bit wider on this tractor
-3 cm pivot distance
271 cm antenna height
0 cm antenna offset

Don’t have the pc on which I have the config on right now, will share it another time