I’ve made some good progress on getting my Observer/Ranger-Ex Quadplane dialed in. I’ve done 4 transition flights and about 20 hover tests and, whilst it is much better after adjusting some of the parameters, I’m still wondering if it could be a little better in VTOL flight modes? I would really appreciate if some could take a look at my attached flight log, which is from a test flight using all 3 VTOL modes on a calm day:
Whilst I am very familiar with APM Plane, I had to get my head around APM Copter tuning to better understand the VTOL behavior of the aircraft. I think the most noticeable change came when I lowered Q_A_RAT_PIT_I and Q_A_RAT_RLL_I. With the default settings I found the aircraft very sluggish and there was a tendency to nose over on take-off. I have also pushed the Q_A_RAT_PIT_P and Q_A_RAT_RLL_P gains all the way up to 0.3 (I think that’s the max, but there is no oscillation so I think it’s fine). One of my major issues from the outset was very sluggish yaw authority (to pilot input) and that was fixed by pushing Q_A_RAT_YAW_P up to 0.4.
My only concern at this stage is the huge difference in sensitivity (to pilot input) between flight modes. Q_Stabilize and Q_Hover are very sensitive, but Q_Loiter has a much softer feel which I prefer. I doubt I will use Q_Stabilize going forward but I am concerned the difference in sensitivity between Q_Hover and Q_Loiter will bite me one day when manouevering near to the ground. I have lowered Q_ANGLE_MAX to 2,500 which makes things a little tamer but in Q_Hover and Q_Stabilize modes the aircraft rotates to that max angle in flash with minimal stick inout. I did try lowering Q_A_ANG_PIT_P and Q_A_ANG_RLL_P but that felt a bit too sloppy (in all 3 flight modes). Any thoughts on how I can tame Q_Hover and Q_Stabilize so that it’s not so sensitive to pilot input?
Here are my latest settings (which were used for the flight as per the attached logs):
Q_A_RAT_YAW_I: 0.018 (default)
Q_A_RAT_PIT_D: 0.0036 (default)
Q_A_RAT_RLL_D: 0.0036 (default)
Thanks for the reply. I updated your post on the ArduPilot forum, let's see if it picks up some attention.
I flew the QuadPlane today and faced some challenges with AUTO and QRTL modes, with the aircraft reacting in a super aggressive way to follow the mission. I use default Q_A_* params for now. What method do you follow to tune these params?
More recently I'm posting in the Ardupilot forum but I have not yet had any help in this regard on that forum either. However, I have learnt quite a lot since my original post here and made some progress although I still would like someone to check out my logs. I have changed my post here to reflect my latest queries and also updated the link to more recent flight logs.
@Jacques Eloff - have you figured it out? I'm also new to flying a QuadPlane and I'm about to get into PID tuning. Would appreciate to hear what you've learned. For reference, I started a post yesterday with some of the questions I had: http://diydrones.com/forum/topics/quadplane-questions-after-first-f...