I haven't worked on my quad in about a month or two, partly because I became busy, and partly because I was at a loss of what to do next since I can't seem to get stable video.
Here's an example of the last flight I took showing how shaky the footage is (high frequency vibrations):
https://www.youtube.com/watch?v=UFz5Df4GzrU
And here's an album showing the basics of the consturction:
Build details:
- Props have been balanced.
- Motors have been balanced to the best of my ability.
- Props are 13x4.7 APC SloFlys (ones in photos are 12x4.7)
- Motors are HK DT-700s
- There are rubber washers between the motor mounts and the aluminum frame
- The gimbal is isolated with the rubber grommets seen int he first photo
MultiWii 2.3 running on a Atmega328p/MPU6050 based board
I'm not sure where to go from here. My plans was to shorten the arms, lighten the overall weight, restructure the gimbal mount, re-balance the motors and props, and hope for the best.
Replies
Not sure what gimbal you're using, but I had similar with my Tarot gimbal, which I eventually found was caused by one of the screws between the camera mount and gimbal motor shaft being slightly loose (yet felt OK when I manually moved the motor).
While trying to fix this I'd altered the gimbal settings - which didn't help much.
Once all screws were tight I changed all the settings back to defaults, and it's been stable ever since.
Thanks for the reply!
I'm using one of those ebay gimbals from China. I'll check for loose screws, and tighten them all anyway. It couldn't hurt. Here's a similar gimbal:
http://www.ebay.com/itm/Brushless-Gimbal-Camera-Mount-w-Motor-Contr...
I almost bought a Tarot 650 CF frame off of ebay last night, just because I am so frustrated with debugging these vibrations. I'm not even sure it would help, though, if the problems are not in the frame.
My plan right now is tear down the entire build and reduce the length of the arms. They're very rigid as they are, but they do experience some twisting -- something I probably wouldn't see if I was using square channels instead of U channels. Cutting back the length will help out a little I am thinking, but it will also reduce the distance between the props. Maybe this will induce turbulence? My plan is to have them separated b about an inch.
I'll also look into ways of reinforcing the arms so they don't twist. Doubling up the U-channels to make a square channel might help.
Any good vibration damping tips? I've been reading this article: http://copter.ardupilot.com/wiki/vibration-damping/