Hello again everybody,

Round two of "organized testing"...today I decided to keep my Nav settings from last time(see previous blog post) and only play around with the Stab PID parameters to see what kind of effect they have on Loiter. I started off by increasing my Stab_P from 3.5 to 5, then to 6, and finally to 7. I noticed a significant improvement overall ability to loiter(no random motion) but there is still quite a bit of drift, which I believe improved as the P term increased. Now when I look at the videos I took this morning, I realize the major problem  with Loiter is that it seems to drift the first time you enter from stabilize, then depending on the P value, it will stop faster(high P) or slower(lower P) and attempt to loiter. You can see that all 3 attempts in the video start off with a drift(because I had just entered loiter from stabilize) and then loiter starts happening. As you can see there is some twitching especially around the Stab_P=7, so I did some more aggressive tuning of Stab_P/D as well as Rate_P indoors after I came back which not only eliminated most of the twitching but also made the copter more solid in stabilize mode in terms of it's tendency to drift...unfortunately I ran out of batteries before I could test these new Stab/Rate settings with Loiter...will work on them a bit more indoors and try again by the next post.

Hello,

This is my first blog(and I mean first ever anywhere) so please excuse the lack of the "bloginess" quality :)

I've been in testing mode with APM1 since the release of Arducopter 1 code. After a couple lost and crashed quads, I decided that my strategy for testing arducopter from now on is to start with a cheap frame/motor/prop combo, basically to iron out any bugs that maybe in newly released code or any potential errors with wiring and installation before installing it on some of my more expensive frame/motor combos. My first application of this method started with the 2.2 code and I've gotten pretty good with tuning the basic stability PIDs, essentially because I had nothing much to worry about and I was able to experiment with more aggressive PID variations to get a feel of what's going on. By the release of 2.3 code, I became mostly focused on loiter/nav/RTL tuning.

Today is my 3rd day of testing, and after running into some bad weather(sand storms and high winds), I was finally able to get some definitive patterns while varying the NAV_P and NAV_I parameters to improve the copters ability to loiter, especially that there was very little wind. I had of course tuned the copter indoors for stability and control and wanted to see what I can get in terms of navigation without changing the control feel of the copter.

For today's tests and the video below, I've followed a few basic scenarios starting from the default 2.3 navigation PIDs and only modified the NAV_P and NAV_I settings. Unfortunately and for some unknown reasons, my logs were all bad and I'm not able to show the KML files for each one of these scenarios, but I hope you get the idea from the videos.

The frame used for these tests is a Scarab Euro (from multiwiicopter.com) with KDA 1050Kv and 8X4 props.