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
Im flying a 800mm size Hexacopter. The ArduPilot site recommends starting at P=.75 and I=1.5
see these links it may help.
http://copter.ardupilot.com/wiki/configuration/tuning/
http://copter.ardupilot.com/wiki/flying-arducopter/flight-modes/loi...
These are very helpfull
Slow descent to 50% throttle looks like too much I parameter in PID regulator.
I your case, I'd recommend to start over full setup. It is VERY important not to skip any step, including full new radio calibration.
Best would be:
1. Save all old values to file.
2. Reset all values.
3. Start wizard with flashing 3.1.5 firmware.
It is very important to make everything at right time in right sequence, it assures you that you did not miss anything important.
I'd recommend the following actions:
1. Set P, I parameters 10% lower that autotune.
2. Make test flight in stabilize and record IMU.
3. See log for vibrations and check vibs are in preferred diapason.
4. If not, get rid of vibrations.
5. Rerun autotune.
6. Make tests once again.
You really ARE brave man to let drone on AUTO mission without stable alt hold.
Hi Andrew
I am also using HK pilot 2.7 as well a beginner to this wonderful hobby. I am running 3.2.1 as my very first version of Mission Planner so I don't know what came before.
As far as setting up the software to fly I encountered a number of 3.2.1 software and hardware issues.
The HKpilot 2.7 has a jumper next to the GPS port that must be removed if you are using an external compass as well as setting the Mission Planner software toggle to external before performing GPS calibration.
There was another listing on this problem with the download of 3.2.1 and that was the value of
ATC_ACCEL_RP_MAX set too low. have set mine to medium 108000 and
ATC_RATE_RP_MAX set to 25000.
Also your throttle mid position setting may need tweaking.
Cheers
Apparently the 3.2.1 download has very low values which cause a problem.
Hi Andrew the pulsating throttle value in my machine was mainly due to Throttle Accel I set it to P=.8 I= 1.6. I still get some pulsating in ground effect however above 2 meters its fine. The ATC value effects Stabilize and Throttle hold roll and pitch response. My machine felt slow and sluggish until updating the ATC values.
Good luck, there is a lot to learn.
Cheers
I has a similar problem and adjusting Throttle Accel PID,s fixed this. See http://copter.ardupilot.com/wiki/altholdmode/
I have PIxhawk on a Y6 with pulsing motors, which I assumed to be sync problems. After recalibrating the motors seem to smooth out, but over time it comes back.
Does switching back to 3.1.5 require a full redo of the setup?
Congratulations "piku"!
While I am waiting for my new motors and props, could you do me a favour? Please make a short flight in Stabilize and Loiter/AltHold and upload a graph showing ThrIn, ThrOut and AccZ - similar to the one I made i my first post. Also a log would be great, then the developers should have a better chance to investigate when time allows. There is only a handful users reporting this issue, so I guess it does not have high priority at the moment... no problem!
Note:The jumpy throttle curve in Loiter may be normal, and may not have any relevance to the unstable behaviour in autonomous flights. That's why I am interested in the graphs I am asking for.
Regards Jan
Some graphs from my tricopter:
- Mini APM V3.1 ArduPilot Mega
- Motor: 3 stk. RcTimer 4215-460kv
- Servo:Towerpro MG995
- ESC: RCTimer 30 A
- Battery: Turnigy nanotech 5Ah - 3s
- 650mm motor to motor
- Props: 14"x4.7" APC
- AUW with 5Ah battery: 1760g
I have tried both the latest firmware Arducopter 3.2.1 and 3.1.5. For this test I used 3.1.5 which was marginally better than 3.2.1.
From the graph it looks like the tri is a little underpowered (ThrOut~620), that is because the setup was designed for 6s batteries - running 3s at the moment as the ESCs cannot take 6s). The tri behaves normal in Stabilize, but in Loiter and AltHold it is jumping around. From the graph I can see that in Stabilize mode the ThrOut is matching ThrIn perfectly, but in Loiter and AltHold the ThrOut is pulsing.
The AccZ is not great, but well within limits +-5.
Motors with higher kv, RcTimer 5010-620kv are under way, better matching the 14"x4.7" propellers on 3s batteries (or perhaps 12"x3.8") - hopefully this will take care of the pulsing motors. Any thoughts?
Regards Jan
This second graph is from an earlier test with Arducopter 3.2.1, enclosed is also the corresponding log file.
2015-03-27 APM 3_2_1.bin
JHIN, I noticed that your Throttle PIDs are also at the default. Have you tried tuning them?
One thing that is different between 3.1 and 3.2, is that the default Throttle PIDS changed. If a parameter is at the default, then it will change with to the new default setting when you change your firmware. If you have changed a parameter, it will remain as it is.
So anybody who is going back and forth between 3.1 and 3.2, while their throttle PIDS are default, will see the effect of this change. The issue could simply be that the default pids in 3.1 are closer to correct for your system than the 3.2 defaults.
It is impossible for us to find one default PID setting that works for all machines. This is why they need to be tuned for every machine.
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