Rover-4.5.6 has been released as the stable/official build for cars and boats. It should appear in the ground stations within a couple of hours of this posting. Alternatively you may directly download the binary (aka “.apj” file) from firmware.ardupilot.org.
Changes vs 4.5.5 are in the release notes and also copied below
I find it difficult to keep S-Curve turns from overshooting (rather than cutting the corner, as expected) despite spending significant time tweaking decel, G, and radius parameters. Above shows those S-Curve overshoots when using very small radius turns at low speed/G in an otherwise well tuned SITL model.
Likewise, pivot turns consistently still overshoot by a small margin, requiring a course correction after making the turn. I can minimize this with careful use of decel and GPS_POS* params, but it seems I almost always get a small overshoot.
I also find that turn behavior is quite sensitive to GPS_POS* parameters in relation to the Z (pivot) axis of the vehicle. This isn’t necessarily an issue, but it is not well addressed in our docs.
All negative behavior is significantly magnified any time the steering and/or speed controllers are not tuned near perfectly, which is a tall order even for experienced users, much less those less accomplished at manually tuning their vehicles.
I have 2 machines - 100lbs and 900lbs. Both work quite well using 4.2.3. I tried 4.5.6 and I see the same overshoot problem on pivot turns. I was not able to improve it to match 4.2.3. I think the S-curves and 4.5 + are not useful for precise pivot operations. Going back to 4.2.3 unless someone fixes this. My reason for going to 4.5 was perhaps better bendyruler performance. 4.2.3 does not work great in this respect.
Your assertion regarding a total lack of suitability for pivot turn applications is a bit aggressive. I know several who have achieved quite a bit of success with their own vehicles (and also my own).
That said, we had some follow on Discord discussion, and this is a hot topic for sure. Unfortunately, the dev team is busy preparing for the annual conference, and I don’t expect to see much movement on the issue right away. I do wonder if @rmackay9 would be interested in hosting a conference discussion on the subject during one of the panels dedicated to upcoming features?
Been away for a while. Are the pivot turns issues resolved? Really want to get away from 4.2. Based on your multiple comments, I should start with the default PSC tuning and be reasonably close. Alternatively, I could guided mode with host computer.
