# Which algorithm is better in an hilly environment

Hello, I am noticing that when using stanley in a hilly field, my tractor has a tendency to fall downhill, sometimes even 20cm for about 10-15 seconds then goes back on track, then falls again. So I was wondering if pure pursuit will solve the issue. Also can someone pleaase explain to me how the sidehill deg per deg value works in pp and if it can solve the issue?

I had that exact same issue last night, no idea why!

We run combine on stanley and sonetimes holds line right exactly bang on and sometimes it drives 10 or more cm beside the line for quite some distance then suddenly manuvers to the line again happens couple times per day

For me it happens always, itâ€™s always downhill aswell

I had it fine in one direction, drive back same way and it just starts wandering off, but doesnâ€™t even try to correct it. Like â€śoh, Iâ€™m 24cm adrift now, thats fineâ€¦â€ť

Yeah we were downhill too when it started

Was it drifting downhill? Also itâ€™s the same for me, drifting around 15-20 cm and only tries to correct it once every 10 seconds or so, then drifts back and so on.

Sidehill deg per deg in PP will turn the wheels uphill on steep sidehills automatically by the preset amount.

PP will hold you on a hill, if the tractor itself can stick to it without sliding.

Integral will try to correct as well if the wanted correction is not happening in time.

So if the tractor is rolled to the right by 5 degrees and i set the sidehill deg per deg to 1, the motor will turn the wheels 5 degrees to the left? I tried integral 15 and it looked like it was doing nothing but iâ€™ll try higher, also changing to pure pursuit from stanley and using sidehill deg per deg, also is 1 too high or what are you usualy using?

Integral doesnâ€™t fix this issue, this wasnâ€™t a side-hill for me but I tried it anyway. It just takes a wander for no apparent reason.

At 5 degree pretty sure its not activated yet but I will have to check the code. But yes that is the idea the more sidehill the more it turns uphill. Deg per degree I have set pretty low 0.06 on the small tractor, 0.1 on the Stieger. Its an assist not the primary guidance.

Integral is pretty slow to act, some like it. I leave it set at 0.

If at around 5 degrees itâ€™s not activated what settings do you reccomend to get rid of that falling downhill behaviour? Also for me sidehill deg for deg might be helpfull because i have some really steep fields, my hill combines max out on them at 25 degrees, and one of my guys that runs a trimble system told me that when he was seeding with a 4 meter vaderstad the tractor almost climbed on top of the already seeded part in order to keep the seeder straight. I think deg for deg might be able to induce the same type of behaviour. To add on this, may be helpfull, the tractor falls of the line and is really lazy getting back up, not wanting to for a couple of seconds then going back up fairly quickly and then falling again.

Hillside combine the type hydraulically level the cab and machine?

This seems to be reproducible also in external simulator (External simulator using a game engine (Godot)) when tilting the field. It seems that when roll is negative the tractor â€śdropsâ€ť off the line and tries to nudge back now and then, but never getting much closer than 20 cm of the line. In another direction (when roll is positive) it slowly gets closer to the line (never reaching it, but this could probably be tuned (with integral?)). No such problem with Pure Pursuit.
Video:
https://youtu.be/QGKUAbobAvg?si=oivEvlRwiz-bkvff

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Yes, they automatically level themselves by raising or lowering the wheels independently.

The self levelling in itself would be tough for the gps. When the cab levels it would not sense roll. If the bno was mounted to the axle then it wouls sense the hill but the receiver would still be level over the centerpoint.

So the combine is compensating for roll and the gps is blind to the angle.

I wasnâ€™t planning on mounting aog on them, I was just using them as an example to show how steep my fields are. I was wondering if anyone has any ideea on how aog will perform in really steep conditions and if it can get close to the trimble mentioned above. I donâ€™t know how it can calculate the slip of the tool given how many variables there can be but who knows.

The current autosteer algorithms make the assumption the implement will follow the track of the tractor pretty closely. Maybe an offset or correction is needed in the setup for some implements. This assumption holds true for fairly flat ground.

However on hilly terrain, especially side hill, the implement usually tracks further down the hill from the tractor track. Perhaps putting the GPS antennas on the implement vice the tractor. Add an AOG mode or algorithm that steers the tractor so the implement versus the tractor pursues the AB line, edge of the previous pass or boundary. After all, it is the implement that works the ground not the tractor. Seems almost irrelevant to a point where the tractor is since we want the implement on the AB line.