Steering Setup Issues

Utility vehicle/Kubota RTV/Buggy vehicle
with
V2 PCB + 5.4.5 + BNO08x + Ardusimple starter kit + Steering wheel motor + RQH100030

Having “fun” (problems) getting the system to follow a guidance line. It starts on the line, but then moves either side of the line, alternating the sides, with it getting further away each side, and making larger turns to get back to the line.

The tractor on the screen doesn’t always look to be at same angle as the vehicle.
Have tried almost every setting multiple times and cannot get it to work.

Can anyone recommend advice?
Also any advice for good settings for this type of vehicle? (compared with the normal tractor-based settings) (Steering is sharper and shorter wheelbase to consider etc) ?

Thanks!

Are you using PP?

What are all your settings?

Have you properly set your steering degrees and Ackermann? Are you confident in your WAS zero?

P (96) < proportional gain fine tune near end of tuning, think of it as smoothing
Motor max (196) < fine tune to keep up with u turn
Motor low (44) < set too low take too long to reach line, too high will overshoot the line
Motor min (22) < Amount of pwm ignored before motor is activated, deadband.

Look Ahead (2.4) < set first most important, too high and low will oscillate, pick the middle
Look Ahead gain (1.8) < For higher speed, not sure if it really works but I like this number.
Side hill degrees (0.5) < amount of steering uphill on a sidehill vs roll degrees
Integral (1) < set last used to increase response if not achieved in time, very powerful start at 1 and very slowly increase

Are you using RTK corrections?

If its really being ignorant there is also AgOpenMicro meant for smaller wheelbase vehicles. I use the regular AgOpen on a small 3038e tractor. The biggest fib the manufacturer gave me was the turning radius. Drag an object from your hitch and measure the circle it creates, most accurate method.

Thanks for your advice

Yes, sorry, using PP.
Had another go today and seem to have made progress, mainly because i have set fusion to 100% GPS**. With just GPS i have achieved a reasonable line following. Still needs improvement and hopefully IMU fusion will assist.
Specs below. They probably look abnormal, perhaps because of the geometry of the vehicle, compared to the normal AoGPS vehicles.
Haven’t got far enough to try UTurn.

100% GPS Fusion
Look Ahead - 3.5m, Look Ahead Gain - 2, Side hill - 0.75, Integral - 1
P - 200, Max - 201 (Unused yet), Low - 20 (Could probably go lower), Min - 35
Counts Per Degree - 15

**
Main Issue : -
In AgDiag, the “From Autosteer” “Heading” was 90 degrees wrong.
I will start another thread for the issue, or search for answers. I had already recently rotated the IMU because of the same issue as above. Now it seems wrong again… :angry:

It doesn’t matter if bno085 point nort east west or South, AOG only compare reading with last reading, and use that to adjust heading.
You can’t get a heading when standing still, the GPS must give at least two points with your set fix distance before AOG know a heading.

Reset all those settings.

Start with :
Look ahead 2.5
Gain Look ahead 1.2
Fusion 50%

P 100
Motor max 150
Low Motor 40
Min Motor 25 (this settings needs to be lower than Low motor)
SideHill 0
Integral 0

Another tip it’s your CDP are too much low, default is 100, i use 88

When reset settings , only tweak one setting every time, and see if it works

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Thanks for all the advice

Will try out with default again.

Update to the above for anyone facing the same issue / interested.

Fusion - 50/50% to 70% GPS/30% IMU. Still experimenting
P200, Max 200, Low 35, Min 35
Look ahead 2.8 to 3, LA Gain 2, Sidehill 0 and Integral 1. Sidehill and Integral to be changed when tested on terrain.
15 CPD

Got a reasonable line following at that. 1m error total, maybe more in certain areas.
Look ahead and low motor could be tweaked more

Steering action is so fast, which in turn moves the GPS and IMU laterally quickly. Hence why low CPD needed. CPD at 55 or 80 (anything >30) for example both produce huge turns and oscillations either side.

Haven’t tried U Turn. Turns with the current setup highlight that the program gets confused by the quick turns/small radius. May need more IMU to support turns

Maybe mounting GPS further back may help to slow lateral movement…but that’s obviously a tradeoff for other factors…

Your P it’s too high.

For that your steering it’s to fast, start at 25 and then up slowly.

Where are your antenna located? in front bonnet?

Look ahead if it’s so far +2,5 it’s hard to make a perfect straight line.

https://discourse.agopengps.com/t/autosteer-basic-configuration/8848/4

Are you using RTK? 1m error it’s huge!

For example with RTK 90% of the time error is +- 1cm with half that time spent sitting on zero.
The worst error i see, usually beside a tree line or coming out of a ditch is 4cm.

I also agree with @Vili 200P is super high. It effectively doubles the error. Try doing all tuning with it at 100P, and adjusting it at the very end.

With RTK your live position should be reliable to 14mm. 1m is a rather large wave.

Though I am with you on the fusion 60 gps / 40 imu is very stable.

What is your steering degrees at full lock? lots of conventional tractors seem to be in that 35-45 degree range.

Sure, will try much lower P and lower LA. That might improve it a lot.

Antenna is on the roof, in line with the front axle
No RTK…yet…

Steering lock is -37 to +37, 7 to 8m diameter (not physically measured, only “record”)

Thanks again for help so far

Go for RTK autosteer is not very good without it most problems go away with RTK. Or at least you will use closer settings to others.

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I can’t follow straight line. I use the basic steer settings video.

For testing it is best to use flat concrete if you can that will eliminates imu and mud errors. From my experience if it’s not working on flat ground it will not work in field.

It seams that your motor is too slow to react try higher low and minimum pwm, lower look ahead, try lower integral, do you have rtk fix? Counts per degree seams high, is your was 0 good ?

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Yes Radmuffins, you helped me for the rtk fix. It is showing that I am moving backwards, but I am moving ahead.

Google Photos

I have made direction reset(turned off AOG and fist take forward)
Now it is better

Tap on the tractor to make AoG flip around

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Now forward is forward. But still no straight line.

The arrow means the program thinks its in reverse, turn off reverse detection.

Otherwise you will need to tap the screen every time you are moving forward and see the arrow.

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I helped you setup a base station, having RTK fix is not a given it is constant struggle to maintain it, any hiccups and no RTK fix.

Close to tree or building not enough satellites in view no RTK fix, tablet doesn’t have internet, phone hotspot doesn’t have internet, no cell phone signal in area, bad configuration of AgIO for NTRIP, your home network doesn’t have internet so you base can’t connect, someone borrows base extension cord, rtk2go doesn’t work no RTK fix.

That’s why its good to check if you have fix when problems starts it’s often because of losing RTK fix, AOG will notify for lost connection with caster.

For settings turn off reverse detection

From your image it seams that you test at 10deg is your IMU angle positive when tractor leans to right? Try on flat ground…

Try higher minimum and low pwm even if motor never stops but follows line then lower pwm to stop motor when on line.

You can record multiple times different angles and average steer angle, you record to right turn for counts per degree.

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Short vehicle with gps over front axle you need to try standley. Otherwise move the antenna closer to pivot axle.

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How short is considered short?

This little unit loves the PP with the antenna out front? (Excuse the old rtk 150 ezsteer, old pic, but antenna location the same for AOG)
Testing Antenna over pivot is a must do for this summer to see any difference.