Abnormal Bird behavior with each flight

ArduCopter Copter 4.6
1

I’ve 10inch Quadcopter.

MTOW : 3kg

FW : 4.6.2

I tunned this vehicle and everything was going good until last night, so what happened is i flied same bird with same configuration last week for almost 18-20min, at that time no abnormal behavior other than compass variance was observed. No motor heating, nothing.

Log of last week

But when i tried flying it yesterday it faced a event of freefall just after 2 min of flight, NO changes were made in bird/configuration but this time temperature of motor was too much, average 60+.

Log of crash

Now what should be my approach to this

2

This is an incorrect statement. There are plenty of changes in the configuration, including major compass changes and thrust-related changes including:

ATC_THR_MIX_MAN: 0.5 => 0.1
MOT_THST_HOVER: 0.2087 => 0.1250
PSC_ACCZ_I: 0.25 => 0.3
PSC_ACCZ_P: 0.125 => 0.2

My first blind guess was the all-up-weight change (a different battery maybe). When a copter is tuned tight for a particular weight, and then the weight drops, the old PID gains may become too high for the new physical layout, which can easily result in overheating. But in this case the battery current usually changes, and here it was about the same for the first and the second log.

The tuning is, by my standards, very sloppy, especially in yaw. If one compares, in both flights, actual versus desired pitch, roll, and yaw from ATT records, deviations in pitch and roll reach up to 2 degrees, and yaw deviates by 5 degrees easily, and by more than 10 degrees in the beginning of the flights. This is consistent with small rate PIDs in pitch and roll (0.06), default angle P values and recommended initial angular accelerations, which overall indicates lack of tuning: we are just in the “basically flyable” state, not in anything looking good. This cannot fly well, but - returning to the topic of the post - there is nothing in the tuning that would cause overheating.

Looking at other sources of information, I noticed that in the first log the reported onboard temperatures were in the range of 31-39 degrees C, where 31 is likely the outdoors temperature as it was reached in flight. The second log features 44-48 degrees. Unless there is something in the physical layout of the craft, you just hit a very hot day.

I have not got the particular nature of the crash that ended the second flight, but all the motor outputs spiked high and the altitude dropped. [Whatever happened, 60+ deg of motor temp might have also been the result of this short current burst too.] - as indicated below, current dropped here, so it’s not the reason for 60+ on motors. It may be that on the colder day the motors were just colder and you were not triggered.

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3

Battery current drops to near zero so perhaps the ESC’s shut down or they lost power. What ESC’s are they and why have you not configured for Bdshot for the telemetry? And yea, tuning is poor.

Bat C
Bat C3406×1047 173 KB

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4

Ah, yeah, current drop at the same time outputs spike up. Thank you @dkemxr. Can be ESC overheating protection or a similar thing.

5

This changes were done as initial flights were completed and after bird estimated its hover throttle, this changes are in respect of throttle accel.

6

Now I’ve configured BDshot for telemetry and presently i’m receiving RPM data.

Will take flight with same conmfiguration as that of yesterday and lets see how it perform.

7

Primary observations shown same kind of things, Motors stopped rotating before fall, indicating either ESC reach its cutoff or power loss.

To varify this things one more flight was taken and bird flied without any abnormalities, excluding higher motor temperature.

So ESC cutoff can be probable cause, and same can be confirmed as on i have ESC RPM data now.

8

Agreed, will look into that aspect too.

This PIDs were fulfilling my requirements so didn’t worked more on that part, will see into it deeply.

9

Hopefully extended telemetry data that includes ESC temperature.

10

I do have ESC temperature and RPM Data

11

Same Issue Persisted

ESC temperature 130+

12

The issue is that the PIDs are NOT fulfilling your requirements.
Correct the notch filters and the PIDs. And the temperature issue will go away.

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13

Yes, slow roasting is best to fully cook an ESC…

You must be following the error prone Rosser Tuning guides. Nowhere else will you find the misconfiguration for the Notch Filter by configuring the RPM parameters.
Start over with either the Arducopter Tuning Guide Wiki or the Methodic Configurator.

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14

I’ll start over with AMC

15

Yes, will reconfigure with AMC

16

Thank you @amilcarlucas

Just wish to know one thing, I’m working on project were in bird will be guided autonomously with the help of radar and vision based sensors, specific landing points will be mentioned and algorithms are supposed to detect place of landing, their will be 4 landing points, weightage for each landing point is same, a tricky part is i need to pick a box at 3rd landing point and need to deliver it to lad point.

Now I’m not sure about tunning part, my senior worked on same kind of project last year, what they faced is upon delivering payload bird was crashing abruptly, now I don’t know exactly what was happening but they said try autotunig without weight so their will be no issues in challenge.

But ardupilot says bird needs to be Tunned with MTOW , so I just wish to ask what should I do

How PIDs should be done, with or without weight?

17

From the 1st page of the Tuning Process Instructions Wiki:
The initial tune of the aircraft should be done in the aircraft’s most agile configuration . This generally means that the aircraft will be at its minimum take off weight with fully charged batteries.

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18

Quick update…!

Revisited parameter setup with AMC, everything was working good. But issue with ESC temperature was still persistent, so to verify working of ESC, another ESC was replaced.

With same setup my bird is working good, have validated it’s functionality multiple times through rigorous testing. Again for cross confirmation Older ESC was placed and then issue persisted, so concluded that fault was with ESC hardware

Summary :

Issue was with both parameter setup and hardware. AMC helped a lot, it’s a great tool, Kudos @amilcarlucas

Thank You

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