After many other issues I’m in auto and the rover seams to searching for a path. Moves ahead a few feet and spins. Then moves ahead again and spins.
Green light locks from Neo7 and Pixhawk 2.4.8
Error log says:
Warning: EKF3 IMU0 ground mag anomaly, yaw realigned
Same error for EKF3 IMU1, EFK2 IMU0, EFK2 IMU1
So is the error causing the spin or the spin causing the error?
It’s a 17HP 48” hydro drive mower set up as skip steer in QGC. Works great in manual.
MowJack
Interference is probably causing the problem. Working great in manual mode can be accomplished with no Flight Controller at all.
I agree with Dave that interference is likely your trouble, but one thing to be sure you have done is to calibrate the compass. On a large vehicle, like a mower, you can use the Compass Learn feature. The initial instructions are here: Testers needed for in-flight compass learning but the code is built in to the recent versions of Ardurover, so you can set an option for a switch and perform the cal easily.
For example, you can set ch7 option (or another channel) to “Compass Learn” on the main tuning screen in Mission Planner. Then, have the messages window open and flip the switch momentarily. You will see the message “Compass Learning Started.” After you drive around a minute or so in circles, figure 8s, etc., you will see “Compass Learning Finished.”
Thanks I’ll do it. Saw compass learn in the RC parameters.
Are you aware of a “learn” mode or methods for the Pixhawk that can learn a rover route, record it and play it back into the FC?
Thanks for help.
MowJack
Google “Ardurover Learn” and choose the 1st result. Or go to the Ardurover main page and enter “learning a mission” in the Search box.
About 25 years ago, I was a mentor for a FIRST Robotics team. There was a routine on the controller that, when enabled, would learn every move the robot made. It had to be sampling the location several times a second and storing it. Something like that would take a lot of memory, but I guess could store to the SD card, but as far as I know nothing like that exists. AND I would contend is not needed. The method Dave pointed you to works well.
For a mower, you normally only need to capture waypoints at the vertices on the perimeter. Then, read those into Mission Planner and convert to a polygon by right-clicking on the Plan screen and then Polygon-From Current Waypoints (a new feature in Mission Planner developed by @Yuri_Rage). Then use the AutoWP feature to generate your full mowing pattern.
Eureka! I’ll try that as well.
Thank you,
MowJack
Compass learn worked as you stated. Still having the spin. Rmackey shared what he called the age old issue of reversing both the inputs and the outputs for the steering. Sun went down so I’ll have to try tomorrow.
Thanks again,
MowJack
If you’re using an external compass module of any sort, mount it as high as you practically can (and disable the internal one). Make sure you use the compass learn routine with the throttle up and the blades spinning - you want to replicate the magnetic field while mowing as faithfully as possible during that procedure. You’ll likely never achieve perfection with a big mower and magnetometer based compass modules, but you can do a pretty good job with them. Once the obsession really kicks in, you’ll surely be back asking questions about GPS-for-yaw 
Thanks Yuri. I’m starting to obsess over winning the battle! Realized today that the two cooling fans in the control box must be causing interference. Will disconnect those and test again. And work through your tips. Some years ago I sank a piece of schedule 120 HDPE pipe in the middle of the same field and rigged a worn out 1972 11HP rider to a steel cable. Bungee cords pulling the steering wheel always to the outside. Pipe circumference was just smaller than the deck cut width. So it ran a spiral path and overlapped a bit. I kid you not the idea occurred to me while mowing on a hot day. Recalled a dif-e-q prof solving some obtuse problem about a destroyer chasing a sub and the solution was a spiral path for the destroyer. Used the mow set up for about 10 years. Kind of wish I hadn’t torn it out. HA!
Thanks again,
MowJack