Hi,
i have a Octa-Quad X frame. it’s about 9 Kg with Accu. Firmware is 4.0.7.
the copter fly and stop in poshold very smooth with no problems.
When i switch to loiter it’s more aggressiv.
The Loiter Params are:
|LOIT_ACC_MAX|500|
|LOIT_ANG_MAX|30|
|LOIT_BRK_ACCEL|50|
|LOIT_BRK_DELAY|1|
|LOIT_BRK_JERK|500|
|LOIT_SPEED|400|
I think you should do some more tuning first - pitch is OK but roll is not so good.
Connect to MissionPlanner and press Alt A and run through that dialog about prop size and battery cells.
Best if you can then set up Harmonic Notch filter, set these:
INS_HNTCH_ENABLE,1
INS_LOG_BAT_MASK,1
PSC_ACCZ_I,0.632
PSC_ACCZ_P,0.316
and for the next flight just do some simple hovering and gentle movements in ALT Hold.
Let’s see that log, then you can move onto running Autotune.
Loiter is the way to go because it’s much more tunable than position hold, but the parameters are in different units. I’d say get the tuning fully sorted out first then address these sorts of things later.
These are the Loiter params I use, but they may be too aggressive for you:
LOIT_ACC_MAX,600
LOIT_ANG_MAX,0 <- covered by ANGLE_MAX but you may wish to keep 30
LOIT_BRK_ACCEL,300
LOIT_BRK_DELAY,0.3
LOIT_BRK_JERK,300
and
ATC_INPUT_TC,0.2
Also your Y axis vibrations are very high, so check prop balance (but usually you’d see high X axis vibes too) and anything loose vibrating against the frame or the flight controller. Also look for wires pulled tight from the flight controller, or loose wires flapping around too much.
It could even be that your vibration isolation in the X axis is correct and working well, but Y axis vibration isolation is different and not working - could be more or less anti-vibration foam in Y axis, for example.
I been under the impression that tuning is more reserved for modes like Stable. GPS should not need any special attention but work out of the box once calibrated. I’m at a loss today build shows a drift of over 2m basically GPS for my build scary to fly.
I have found these Loiter parameters relatively easy to tune as they are really personal preference. But I definitely agree with Shawn that you need a solid basic PID tune 1st.
Note: Somewhat related; I have been testing the addition of this PR ( Controlled and Fast) in Master the last few days and it’s quite remarkable how well a high thrust/weight craft will fly a Mission at speed!
Dave in the last 5 years I never needed to adjust the GPS the thing is he is saying that his bird is smooth before engaging into GPS so please make note of that. when the last time you tested in the air with the new modes?
Hi Brandon-I’m not following the point about adjusting the GPS. What/where is the context for that? I think he’s saying there is a difference between PosHold and Loiter in how braking and other dynamics are working. Both are GPS modes. That is certainly true but Loiter has more tunable parameters as Shawn said.
Which new modes? I have flown quite a bit this week with the latest Dev version which has all the content of Beta 7 plus some other stuff.
There seems to be some issues with GPS for me in loiter that i never seen before rendering Loiter un usable. I notice it immediately. Why i ask if you seen it in the air. I do no think it is PID related as non GPS modes are fine smooth.
Ah OK, I understand. I have been doing mostly Auto Missions and not a lot of manual flying so probably wouldn’t notice. I’ll check it out. I can try with several different Flight Controllers all of which will be running 4.2.0-Dev.