No. In the log RATE>R/P out as I noted. Just look at the motor outputs. You will need a considerable amount of experience to use logs effectively, I can’t summarize it here. Read the Wiki’s, watch some YouTube video’s from the Ardupilot Dev’s.
1 Like
I checked this graph in my logs to understand it.
I think, in RCOUT, all 4 motors must have almost similar output at any given instant of time. Is that true? or anything else too to be identified their?
…………
In a hover yes.
1 Like
So,
Please check the logs again for today’s flight errors. Logs with date 29 March
- 11:27 log is with PID reducing by 50% of the original value.
- 12:15 log is further reduced by 50% of 1st log value (11:27 flight value)
As per my observation, 11:27 was quite a better flight than before and was near to stable.
12:15 flight was something kind of beginning racing speed type. Not good for someone like me.
Set the PID’s back to the 11:27 parameters and then set these:
INS_ACCEL_FILTER,10
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
PSC_ACCZ_I,0.4
PSC_ACCZ_P,0.2
Perform another short hover flight in Altitude Hold until it’s hovering at throttle mid-stick.
1 Like
Will try this and update. Thanks
By the way, I was just going through the complete parameter list to identify what these parameters are and its purpose.
Found one thing out of your given values.
Ins_log_bat_opt has 3 options 0, 1, 2. Whereas the value provided by you is 4.
Just wanted to confirm if that is the correct one provided.
I will be performing a stabilize flight first with the given settings and then the hover in althold.
You mentioned that try althold hover until it’s mid stick. I guess, that is roll, pitch, yaw stick in middle and throttle at any position but not controlling it.
Additionally, wanted to ask you, have you checked an error of ekf velocity variance? Actually, this all started with the issue of ekf for velocity and position variance failing in loiter mode. Please check if you can put some insight into it.
Thanks for your time
It’a bitmask, use 4.
Hover with mid throttle stick to learn the Hover thrust value.
Continue with tuning and worry about this if still present when you are done.
1 Like
Logs are updated in the drive. Please check for a single log at the latest with the date of 30 March.
Due to wind of above 4m/s, I was able to perform only one flight in stabilize mode. Will wait for the wind to get calm for Althold and Hover tuning.
Note- This is a simple update that the test flight was carried out for a half part. Due to high wind, it was difficult to decide on any issues.
Done test flights today.
After putting in Althold mode, Altitude increase and decrease goes on. I tried to hover it at the stick center but continuous input was required to control altitude plus position due to slight wind. I wasn’t much concerned about the position though, altitude variation is much high. Kindly check the updated latest logs of the 31st.
Thank You
Bad oscillations in the motor outputs, and attitude control is poor.
I believe Y and Z axis vibrations are too high. There is even a message about it:
Vibration compensation ON
So there might be two issues going on there
- something pulling on the flight controller or rubbing against it in the X axis, usually wiring
- maybe prop wash or other items unsecured affecting the Z axis, or frame vibrations and resonance
This and the poor attitude control will be affecting the motor outputs and altitude control too.
Try to fix the vibration issue before you do another filght!!
And load all the params I’ve specified too.
Do you have a 4 cell LiIon battery or what exactly?
Some of the voltage values dont make sense.
Revisit the Initial Parameters screen and put in the cells and battery chemistry and accept the new voltage values it provides.
Definitely set these too:
BATT_FS_CRT_ACT,1
BATT_FS_LOW_ACT,2 or 3
If there seems to be a problem with battery failsafe triggering too soon, then NEVER change those values but recalibrate your voltage sensor so it is more accurate at the low voltages. A high resistance connection or poor battery could cause that too.
Set these:
MOT_SPIN_MIN,0.12
INS_HNTCH_ENABLE,1 ← set this then refresh params to see the rest
INS_HNTCH_MODE,1
INS_HNTCH_REF,0.12
INS_HNTCH_FREQ,90
INS_HNTCH_BW,45
INS_HNTCH_FM_RAT,0.7
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
The GPS HDOP is poor, try these different values to see what works best for you:
GPS_GNSS_MODE,5 or 65
Try another flight when you can, and try to spend more time in AltHold
I think the PIDs are too low, if the next flight is very good compared to previous flights then try these:
ATC_ANG_RLL_P,6.0
ATC_ANG_PIT_P,6.0
ATC_RAT_RLL_P,0.11
ATC_RAT_RLL_I,0.11
ATC_RAT_RLL_D,0.0055
ATC_RAT_PIT_P,0.11
ATC_RAT_PIT_I,0.11
ATC_RAT_PIT_D,0.0055
but take off in Stabilise and land immediately if oscillations are worse.
Yes. It is li-ion 4s battery.
How to recalibrate the voltage sensor.
So, you mean, i should do the settings till gps_gnss. And do the flight in stabilize and then in althold.
Later do the other settings of PID and take the flight. Right?
Ins_accel_filter =10 is set as suggested by a member above.
These are the correct settings for 4 cell Li-ion
BATT_ARM_VOLT,12.70
BATT_CRT_VOLT,12.00
BATT_LOW_VOLT,12.40
MOT_BAT_VOLT_MAX,16.40
MOT_BAT_VOLT_MIN,11.20
You’ll need to first work on solving the vibration problem, then apply all the settings I’ve specified before you do another flight.
Just changing settings now wont help while the vibrations are bad.
If you get through that and a test flight is good, then apply the PIDs I suggested.
I just tried to tighten the things as suggested. No PID settings were changed.
Updated all the settings of Hntch as suggested above, and did a flight. That was a very bad flight. It was much not in control. Somehow, I managed to land it safely. Check the 8:02 flight in the April logs.
Then I changed all the settings back to the previous one. The initial parameter sets INS_Accel = 20, whereas the older values were 10. I changed it back to 10.
The Hntch filter was disabled. Only GPS_GNSS was set to 5.
Now, this flight was good, stable with not much movement. A little altitude variation was still there. Nothing else apart from that. But that did not last long as a propeller hub came off mid-air. Tiny injuries are there and are taking a rest now. Check the 8:35 log.
Already changed the motor and its hub set to the one which cannot come out mid-air.
Cant access logs, post a new link
The vibration levels are still too high. As Shawn mentioned, make sure that something isn’t lose on the airframe, or none of the wires aren’t pulling or bouncing on the flight controller. If a prop came off in flight there’s some other mechanical issues you need to address.
That propeller issue is already addressed and resolved with required changes as mentioned above.
In Fact there is nothing loose in the airframe. Compared to the first flight, observed very less vibrations in the 2nd one. Don’t know if that was due to parameter settings.
So I am confused with the reason behind it.
INS_ACCEL_FILTER should definitely stay at 10
In fact it can be different and 20 used to be the default, but 10 is so much better.
Vibrations are definitely still a major problem. I dont know why they are lower in the second flight, but still too high. Clearly something external changed. The fact remains you’ll have to do something about this problem before tuning can be effective and flight can be stable
You’ll have to do some reading in the docs and see what you can do to better isolate the flight controller.
Maybe post a pic of how it’s mounted now.
HNOTCH wont cause the instability and oscillations you are experiencing since it appeared to be configured correctly.
I strongly advise to keep the settings I recommended, they were actually doing their job. Just alter these:
INS_HNTCH_FREQ,85
INS_HNTCH_BW,42
I’m fairly certain that when you fix vibrations then these PIDs I recommended will work well enough.
At the moment PIDs are so low trying to correct for perceived oscillations and instability, that I think is caused by vibrations, that they are effectively contributing to the problem.
Sorry members,
I am a bit late in responding but I was stuck with something more important.
So, coming back to our discussion.
-
I had made no changes in the previous 2 flights or any of the flights, till April 1 (last log). So, I have no idea how one was full of vibration and another flight was with a little less. As mentioned, I have attached the images for reference. Let me tell you, that I was fed up with prop coming out (Along with the motor hub mount) issues and so I have made recent changes with the motor, ESC and propeller set. This image is with the latest configuration as of 16 April.
-
After changing the propulsion system, I carried out a short flight with all the old parameters just to check how the new propulsion system work, and whether there was any role of my old motors in vibrations and other flight issues. So, the log of the same is uploaded on the drive. The link is here. April 2023 Logs - Google Drive
What I have observed is, the flight was going smoothly. ofcourse a little bit of altitude variation, wind played with the position drift (but overall, everything was less compared to the previous issues). I request you to go through the logs to cross-check (I did but not with your expertise.)
The latest logs have today’s log and the reference log will contain the logs of 1st April
Thank You