After a rather painful and stressful process of getting my new APM 2.0 board working on my 3DR Quad, I have finally got it to fly, but it is really twitchy and scary.
I had recently started with an APM 1 board, and had that flying very nicely including a really good loiter. However, I seemed to have had the IC2 problem on that board, as the quad insisted on committing suicide on a regular basis, and then everytime. That board is going back to Martin at BYOD to see if he can fix it. Luckily I had pre-ordered an APM 2.0 board, and even more luckily it turned up yesterday. I effectively built a new Quad from spares to eliminate any problems, including new ESCs and motors. It was very stressful getting it to work, with the problems connecting to MAVLink, having to manually recalibrate the ESCs often, going back to square one so often with not being able to complete a firmware upload, Set Up and hand test cycle without something locking up. Anyway, eventually I have succeeded, although I am using my Xbees where possible to communicate between Mission Planner and the board.
When flying the Quad, it appears to be ok for a few seconds at a time, and will then twitch, sometimes quite violently, including dropping in height. The throttle response seems a bit digital. There is a bit of wind, but nothing that the APM 1 board would not have coped with. I do not have the sonar fitted, as that seemed to cause a problem and I have taken off as many ancillaries as possible to cut down problem sources. I have not changed the Stabilise PIDs at all from the firmware update. Any ideas on what might be causing the problem, or what PIDs I should be using for an APM 2.0 board?
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Just to add a bit more to this. Other problems I am coming across are that sometimes when I connect to MAVLink using my Xbees, the sensors don't work. Other times, I get ready to fly and one motor/ESC starts beeping, so I have to manually recalibrate it. Other times, everything looks fine in Mission Planner, sensors working, but I cannot arm it. It really seems hit and miss as to whether I can get everything working to try and fly it.
I had a go at tuning down the PIDs, which seems to have helped a bit, but there are still some major twitches, at times the throttle seems to stop for a heartbeat and it is simply not stable. Unfortunately, the wind has got up, which is making it more difficult to control and try and make sense of its behaviour. Would be really grateful for somebody's inputs.
Has anybody else actually flown this board yet? I am using a stock 3DR kit, using a Futaba T7CP tx with a Corona RP8D1 rx.