qloiter mode should respect parameters Q_ANGLE_MAX and LIM_PITCH_MIN/MAX
In auto mode, it seems that an entirely different code path is followed, it applies LIM_PITCH_MIN when landing and that defaults to -25 degrees. When doing waypoint navigation, it uses ANGLE_MAX constrained by a function of throttle. But there are no comments explaining how that is intended to work, and it’s not obvious to me what the C code is doing
Perhaps @iampete has looked at this before…
There was a little bit of western wind this evening, maybe around 10km/h.
I switched my depron blackfly to qloiter, with this light wind it was able to keep position in a kite attitude with a lean angle around 45°. Then I pushed pitch stick full forward and did not gain one more degree, it was already the maximum. After some seconds I switched to qhover and was able to get around 75°.
That’s not a big deal but good to know.
@kd0aij
Back again, now with Q_FRAME_TYPE = 0, as recommended.
Up to Q_ANGLE_MAX = 30 not bad. Could you have a look what happens at 0:58 in the Video. Roll seem normally stable. Strange QLOITER at the end.
At that point, I think motors 1 and 2 are near minimum throttle, which would result in a loss of airflow over the elevons, The initial uncontrolled yaw is in the CW direction, which indicates that motor torque was insufficient to fight a tendency for CW yaw. This is an unfortunate disadvantage of using torque-based yaw on a quad plus airframe.
Is there some reason this airframe would want to roll left as you begin to pitch the nose down?
I think you will need more bodyframe roll authority from the elevons to fix this.
I think you mean the Commanded Roll phase.
But I mean the Pitch Phase after this and the Roll-Stop Phase.
After a certain Value (?) of Pitch, the Roll control is made by the Elevons as I interpret it because the motors are working on the same RCOU. And these reacts verry weak.
In vertical Position Roll control is established by motor 1 and 2 and this is perfect, hard as set by the Params. There are also 2 different systems to control roll depending on pitch but only one set of Params.
Is there a possiblity to adjust it?
Both major yaw (bodyframe roll) deviations occur when motor 1 has been at minimum thrust for a while. This indicates that something is forcing a CW rotation, maybe turbulence?
Interesting problem, this is my second quadcopter tailsitter…the first one, (a Z-84 conversion) we discovered that often if you initialize upright, then the EKF and DCM are not aligned and will not arm, giving DCM “some” axis inconsistent x degrees pre-arm fail messages…the solution was to momentarily lay it in fixed wing position for 10 seconds or so and let them align, then bring it back upright and arm…
On my new quadcopter tailsitter, I am having a similar problem, yet different…laying it on its belly for any amount of time will not allow arming upright…It must be lower at least 45 degs toward horizontal to allow arm…the pre-arm message is “Check Mag field”, yet MAG health is 100%…I did calibrate the MAG using Tridge’s new Large Vehicle Cal, so perhaps some of second order stuff, does not get calibrated, and is causing the issue?..I can watch on the little OLED display the arming readiness report and it flops/back and forth at about 45degs tilt from “failing” to “passed”…
here is a log of some hovering in the garage for yaw tuning and you can see a disarm and re-arm attempt toward the last flights where I have to tilt it to get it to arm…
its very difficult to do a full compass cal on this, since its an ultralite foam board “box kite” test vehicle and not as robust as I would like…doing the “twist” with it might pull off the FC!
Well it appears to be due to using the large frame compass cal…I managed to do a normal mag cal…got different offsets and all the second order terms cal’d…now it just does the DCM/EKF alignment stuff…after every flight and disarm, I have to lay it down for 10 seconds to allow them to re-align, then I can put it upright and arm…will have to tell Tridge about the effect of not doing a full mag cal on a tailsitter…
finished yaw tune and its locked solid… loitered outside in a light breeze well (4mph)…due for 4-5 days of wind and rain…Sunday looks to be the transition day for the BoxKite…