Special thanks to Paul Dowling and Jason Short for their help with PID's tunning! I would have never taken off without their advice.
Both stabilize and simple mode work flawlessly.
The beast is flying with four 4 cells batteries, 400 gram each. wingspan is 120 cm. Propellers are 14 X 7 3 blades.
Total flight weight: HEAVY.
Comments
I can see the tricky take offs with higher RATE_I values, but it corrects faster against wind!
With a high I value, I think that the correction happens faster and more aggressively. It is a multiplier as I understand it.
Read the flight modes in the manual, they have expanded that chapter a bit, i learned that RATE I takes care of wind.
''Rate_I is used to compensate for outside forces that would make your copter not maintain the desired rate. A high I term will ramp quickly to hold the desired rate, and will ramp down quickly to avoid overshoot. A low I term will take too long to have an effect and may cause undesirable overshoot. It's better to have an I-term of 0 than a poorly chosen I term.''
I guess if your I is too high then it overshoots?
I think the I-Max is the maximum you allow the I value to scale to. So I suppose if you got a gust of wind, the I value would start to increase to overcome the wind, but it will only increase to the maximum value. I have absolutely no clue what in-flight effect this has. I haven't really played with that value yet. I left it at the default from APM 1.55 (old revision) and haven't been brave enough to change it. When I finally get out and fly 2.0.45, I plan on using the default value that comes with that revision. I will try to scale back my stabilize P values and see what happens! Thanks!
having my stabilize roll and pitch at 2.2 makes me think that lowering those values would get rid of the wobbling. My values were about 3.3 and the model was wobbling; lowering those worked out.
I have a question for you: by lowering your 'max' to 1000, what do you change?
Looks really stable! Wow. I have a very heavy Octo setup. I am wondering if the general rule of thumb for larger multirotors is lower PI values. I was flying with mine at:
Stabilization PI
p 3.84
i .024
max 1000
Rate PI
p .105
i 0
max 1500
and I get a large wobble when descending. Any advice?
Jeff:
I'm not landing on the batteries of course, I have this metal rods as legs instead. they are shouting to be replaced by some kind of carbon fiber rod.
So you have similar values? This quad is flying at 4 kilos and a half... how can the values be similar? I'm confused.
I have seen your video of the gopro on the nose and a battery on the tail. Is your balance ok?
SORRY EVERYONE FOR THE LATE REPLY!
Jeff E: Yes, the batteries are strapped underneath each motor.
I.S.: Each battery supplies each motor, with no PDB. I used to 'fly' with 2 batteries and a PBD, but the flight time was too short. Also it felt like I couldn't tune up the PID values enough in order to hover stably because it was too easy for the motors to change the copter's attitude, making it wooble. The batteries, at 400 g each, add inertia to the system, and the autonomy rises to around 8 and a half minutes.
I also felt I needed to lower the RPM's on the props. I was running 12 X 6's, RPM's were high and the wobbling was snappy. 14 X 7's 3 blades are the maximum the motors can take and lowered the RPM's greatly.
ionut: I am using a Futaba 6EX 2.4 ghz. I installed a pot and created a digital in-radio mix in the tx to get 4 flight modes.
Michael Oborne:
PID's are as follow:
STAB ROLL= 2.2 STAB PITCH= 2.2
STAB ROLL I= 0.001 STAB PITCH I= 0
RATE ROLL P= 0.073 RATE PITCH= 0.073
RATE ROLL I= 0 RATE PITCH= 0.001
I will be tweaking them up in the next couple of days, let me know if you want updates on the values.
Cheers everyone!
E
what pids did you end up with?
What Rx transmitter are you using?
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