We are working on 15 kg quadcopter with 30*10.5" propeller. We did autotune for multiple times . By this we get stable copter while it is hover but when it cruise with minimum speed of 5 m/s it gets unstable.
Post a link to .bin flight log.
I attach drive link which contain 3 log files.
https://drive.google.com/drive/folders/1Lb7umlcELadhx_5L1i9Yj2mRgfiNOCq6
Update to latest Stable version of fimrware.
You should have configure the Notch Filter before running Auto Tune. Set these:
AUTOTUNE_AGGR,0.1
INS_LOG_BAT_MASK,1
PSC_ACCZ_I,0.32
PSC_ACCZ_P,0.16
make a short hover flight in AltHold to collect data to configure the Notch Filter.
Review this before doing so Setting Motor Ranges
Thank you so much,
I will do it by today and let you know
I did as you said, by the result my quadcopter can cruise at max 9m/s but it heavily wobble and become very unstable while breaking. I determine notch frequency and apply it and after that i again did autotune. but still my quadcopter is wobbling and heavily unstable while breaking at 9 m/s and its look like drone will crash. Now please suggest what to do.
Only a log will give us clues
I attach drive link which contain 4 log files.
https://drive.google.com/drive/folders/1OZMMH9hdyvrU9QHea_TF-D2k8RPGcgn6
If you post more than 1 log identify what they are. Which log is post Auto Tune (not the Auto Tune session log)?
I am again attach 2 log files with naming. The file named max_9.2_m_per_s is flight of autotune and also i cruise up to 9.2 m/s after autotune . both are in same log file. And the file named max_7.1_m/s contain flight of cruising in auto mode but it got unstable while braking and cruising.
i updated last google drive link because i am unable to attack new link here.
Vibrations are bit of a problem, anything over 20 in the vibration graphs needs to be investigated and reduced.
You need to set these for safety - 30inch props and ignoring these parameters is a recipe for disaster
ARMING_CHECK,1
BATT_ARM_VOLT,44.30
BATT_CRT_VOLT,42.00
BATT_LOW_VOLT,43.20
BATT_FS_CRT_ACT,1
BATT_FS_LOW_ACT,2
FENCE_ENABLE,1
Check and adjust the fence radius and altitude to suit your environment.
I think your thrust expo is too high, it should probably be:
MOT_THST_EXPO,0.77
but no higher that 0.8
This thrust expo could be related to your instability issues.
Changing this will mean you should also use MissionPlanner motor test to check and reset your MOT_SPIN_ARM and MOT_SPIN_MIN
Your hover thrust will also need time to relearn, and there may be a few dependant parmeters to change after that: PSC_ACCZ_P PSC_ACCZ_I INS_HNTCH_REF
The harmonic notch filter is not working properly, change these:
INS_HNTCH_FREQ,30
INS_HNTCH_BW,10
INS_HNTCH_REF,0.14
INS_HNTCH_FM_RAT,0.7
After you’ve set all of those, and done some work on vibrations, do an ordinary test flight in AltHold and Loiter, nothing radical.
Let’s see that log to check how the changes affected performance.
I set all the parameters. After that i also did autotune of roll and pitch axis. After autotune i take one flight . My drone cruise upto 10.6 m/s but it got heavily unstable while braking. I observed that up to 8.5 m/s it did not get any problem for braking but after that braking make my quad unstable but while cruising copter do not face any problem. Here I attach link of drive which contain latest flight of 10.6 m/s .
https://drive.google.com/drive/folders/1Ke9GMMFNxxuYN75KBpEnwA8idtfq-yBF
I quite firmly believe you should have
ARMING_CHECK,1
BATT_FS_CRT_ACT,1
FENCE_ENABLE,1
plus having the battery failsafe levels too low will eventually reduce the capacity of your battery or cause a crash sooner than you expect. Unless you’ve got some particular cells with a non-standard voltage range you should have:
BATT_ARM_VOLT,44.30
BATT_CRT_VOLT,42.00
BATT_LOW_VOLT,43.20
If you are worried about battery failsafes occurring too soon, or false alerts on high current drain, then adjust the timer BATT_LOW_TIMER or change to using the sag-compensated source BATT_FS_VOLTSRC
The vibrations are too high for my liking and I would do more to improve that situation, but there is no clipping so that is something…
If you were satisfied and capable of taking manual control in a fly-away (Stabilise mode) you could go ahead and set
ATC_THR_MIX_MAN,0.5
The way the vibrations are now will be affecting the Autotune result.
This can be adjusted
INS_HNTCH_REF,0.17
and these should be:
PSC_ACCZ_I,0.4
PSC_ACCZ_P,0.2
What motors, props and ESCs do you have?
Can you supply o photo of the flight controller and wiring?
Our Propulsion system contain.
T-motor antigravity mn 8014 100kv 12s motor
T-motor flame 80a 12s v2 esc
T-motor G 30*10.5" Propeller
12s 22000 mah battery
Pixhawk cube orange flight controller
Here 3+ gps
For detailed view you can refer to our last year Youtube video which contain all the detailed information
OK, for those ESCs you definitely want these values:
MOT_THST_EXPO,0.4
MOT_PWM_MIN,1100
MOT_PWM_MAX,1940
and you may have to check and set MOT_SPIN_ARM and MOT_SPIN_MIN again.
You need to secure all the wiring to the frame but leave enough flexibility where they plug into the flight controller so they wont transfer vibrations.
None of the wiring, especially the ones with spiral wrap, should touch the Cube or carrier board.
Those long stretches of wire should be supported - the ones that enter the FC housing then hang across mid-air before plugging in. These will be amplifying vibrations.
There shouldn’t be any wiring anywhere that is just sitting loose or hanging - everything needs to be secured, except where it needs flexibility right at the end where it plugs into something. (I know I’ve said that twice!)
The wires should NOT all just be cabled tied to each other, without also being secured to the frame, or it will be a big weight pulling on the flight controller.
That antivibration mount is OK for smaller low profile flight controllers.
If you fix up all the wiring you might be able to remove it. Or change to using this type specially designed for the Cube to keep the IMUs central.
EDIT:
I was watching the video and you can see the GPS cables shaking. They need to be secured to the GPS mast, then baseplate or frame, then jump to the FC.
I did as you said but beore that my drone was more stable than right now. I take flight in althold and auto flight mode. But it get unstable in 5m/s speed only. The previous parameters was quite stable for quad. Here i attach 2 logs of flight with different changes in parameters.