Hi.
I have a problem after updating AC to 3.2.1 from 3.1.5.
When in Loiter, the the speed of the motors rev up and down/pulsate quite rapidly. This was working fine when I was using previous versions of arducopter.
I have downloaded the logs, and have looked into accX, accY and accZ. These seems to be inside the range specified in the wiki at arducopter. (Log_vibrations.bin)
Please have a look at the Log.bin, and note the difference between ThrIn and ThrOut when I'm in Loiter mode.
Anyone having any idea what the problem may be?
Replies
Hi Leonard,
Thanks! I thought it was still on the vibration limits. Pardon my ignorance, but what do you mean by as I put PID loop if I may ask? I strictly followed the wiki regarding vibration dampening using kyosho zeal. Should I use the 3M foam tape instead?
Also is it necessary to not have the gimbal installed while performing autotune?
Hi Elvin,
What I am saying is the additional accelerations caused by Alt Hold are just enough to mess up the inertial prediction of height and climb rate. It is close to the breaking point before and Alt Hold pushes it over the edge.
Vibration dampening can be a fussy thing to get right, especially on the APM. Make sure there is nothing flopping around that could hit on the frame. Make sure wires connected to the APM are secured and won't flop around too much but leave enough length so they aren't tight. Make sure all screws are tight and your battery is secured hard against the frame.
The best vibration isolation I have found is the latex foam sold by Hobby King with some thin double sided tape (I use carpet tape). I use squares approximately 12mm on the side. This can tear during a crash so make sure you check it if you crash hard.
http://www.hobbyking.com/hobbyking/store/__26457__Anti_Vibration_fo...
If you have the gimbal installed during autotune make sure it is powered. If you find the tune isn't good then try without the gimbal.
Hi all,
Sorry, I am a little late to this party.
Is anybody having this problem with AC3.3rcX?
Hi Leonard - I think you'll find no-one on this thread can try 3.3 as they are all on APM.
So can we safely say that the issues that they are experiencing on this thread are unique to APM and not Pixhawk ?
Hi,
I am one of the few who reported early in this thread, when I downgraded from 3.2.1 to 3.1.5 it fixed my issue. I am only able to upload the log file now, as I took a break to did some South Island New Zealand videos. Then when I came back, unfortunately my APM powered H600 quadcopter had a crash.
Well now my H600 is repaired. I then flew on 3.1.5, then upgraded to 3.2.1. It seems I am not suffering from this issue. I did a change a few components and also my H600 is about 200g lighter when it was on 3.2.1 before. The arms are now longer but stiffer, I changed the double sided tape foam on the APM to be a double sided tape silicon.
I measured my vibration on 3.1.5 and 3.2.1, seems similar but maybe 3.2.1 is a little worse, but its within tolerance. Here is graph where I flew indoors just hovering for a few mins.
Here is a log file of one of the flight
Log file
I am still new to log file analysis but here is a screen shot of CTUN -> DAlt, CTUN -> BarAlt, GPS -> RelAlt. It seems to be ok now.
HI there,
When you downgraded to 3.1.5, did you have to retune your PID parameters? I attempted my first test flight today after downgrading and the copter just lost balance and fell over. It was as though the Stabilise and Pitch/Roll Rate P values were too low.
Yes, I did PID autotune and compass calibration. It is also a good idea to do factory reset after the firmware update.
3.2.1 DJI450 APM 2.6 810Kv 10x4.5 3 cell
After making changes to PILOT_ACCEL_Z FROM 250 TO 50 and INS_MPU6K_filter = 20
AltHld is better. Today I ran Auto Mission with ROI had Alt set to 15 lost Alt on the way to first waypoint
and never regain it very low maybe 25 ft ? Had RTL set at last waypoint then it did go up and return.
2015-05-10 08-20-40.log
Guys, you can't just take and use everything is written in this topic thoughtless!
Analyze what is all about.
See, PILOT_ACCEL_Z changes only the way copter reacts PILOT input. It does not affect AUTO missions. In fact you are one lucky guy to get your drone back in one piece.
The man who posted about setting PILOT_ACCEL_Z to 50 wrote that he is NOT using AUTO mode, so it was partial solution that fits for him, but not resolve issue.
In fact, there should be some error in math concerning use of Z accel in altitude hold that can not be corrected with random settings change. To get reliable result you should be aware of what you're doing.
I recommend:
1. Vibroisolate controller. In perfect case - redo all motors and prop balancing.
2. Flash 3.2 (in my case it's acceptable compromise between features of 3.2* version and stability of 3.1.5
3. Configure drone from scratch. Redo all calibrations, especially compass needs attention.
Run autotune, and then fine tune PID's on fresh battery.
4. Make at least 5-10 successful flights in different weather conditions in manual mode before starting AUTO missions.
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