Some news about the Quadrocopter project
Such a long time after my last post, here is an update about the Quadrocopter project. The short version: It’s working!
And it works quite well, although it took a lot of tuning and testing to get it stable (and there’s still room for improvement).
However, before it worked, there were some problems to solve.
The first and most serious problem were the propellers, which were very badly balanced. This caused vibrations which the Software couldn’t compensate and made the Quadrocopter very unstable in flight. It took almost 2 months before I determined the propellers as the cause of the stability problems, as I always looked for a problem in my Paparazzi config and tried to solve it in Software, because I thought the vibrations were normal (they didn’t feel that serious when holding the Quad in my hand). However, when I balanced the props using small strips of tape, the stability problems were mostly gone.
Next I had to tune the control loops, which I mostly did by trial-and-error, trying to find the most stable settings. They still are not perfect, but they work in most cases.
I also managed to get the altitude controller working, which measures air pressure to determine the current altitude and then tries to hold the Quad at the same level. This works very well as long as there is not too much wind. However, with wind, the pressure levels vary too much so the Quad won’t stay at the current altitude level. But as flying with strong wind is not really much fun anyway, this isn’t a real problem at this time.
All in all, I’m very happy with the current performance of the whole system, even though it’s not perfectly tuned. I'm currently having a lot of fun flying this great aircraft :-) .
At this point, I’d like to express my thanks to the Paparazzi project and all it’s contributors, who did (and are doing) a great job in creating all the hardware and software as an open-source project.
Finally, here are some pictures of the Quad in flight: