I think my quad may be a tad too powerful and too light.
It's a custom build with lightweight modeling plywood base, aluminum arms and
4 x 1100k/V, 18A max motors w 9x4.7 APC props. Running APM2 board with Arducopter 2.3.5 (the latest).
The quad behaves like a hummingbird on crack:
Gradual increase in throttle, take off about an inch, add a tiny bit of throttle to rise, SHOOTS UP 60-80 feet in the air, like a rocket. [ It lifts at about 30% throttle, which I found surprising ]
Oops! Pull the throtll back a *tiny* bit, drops like a stone, while tipping forward a bit and gaining momentum.
Try to compensate with pitch control, tiny movement, drone dips 45 degrees and shoots off at 20 miles an hour downfield.
Clearly I need to tune something, and I will go ahead and do that.
Beyond tuning though (or before tuning), should I reconsider the quad design and build? Is it possible to tune this beast down to tame it, or is it just too overpowered and light?
Should I also be adding a bit of weight (maybe a second battery), or a camera to make it more stable?
Or can I effectively tune it to be as stable as some of the ArduCopter videos I see, where people can reach out and nudge it.
Right now, I wouldn't get more than 100 ft close to the erratic flying decapitation machine I have built. ;-)
Anyone with experience with an overpowered multi-rotor who has had success or not with tuning it to stability?
[Before anyone says: "Go read the wiki, and tune it idiot" - I am at the "First Fight" section, which is before Tuning. I have read all the sections. I will proceed step by step, but I'm asking if my quad design might be inherently unstable and cannot be tuned]
Replies
The first thing to do with a powerful quad is to tune down the P-Rate value. Mine starts getting controllable at 10 or below (normal is 14 or so). I have strong motors and have tuned it down to "9.5". If possible add some throttle curve in to help.
PS. Cannot pull logs, the code "hangs" when I type "logs". A problem for another thread, but mentioning in case someone asks me to post logs.