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.