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
Some other suggestions: I changed the pink inside APM case for a grey one and put a piece of electric black tape on the upper side of the APM case, I close all air entrances with scotch too because if I blow the APM connected to the pc I had altitude changes. I'm waiting some harware to change in the copter that had this issue to try again.
Try to connect the copter to MP, open tunning window check alt and check what occurs if you blow your APM or if you turn on and off a light and if you don't do nothing
I have the same problem including the altitude hold I tried reflashing it the next thing I know is my APM is dead :(
https://dl.dropboxusercontent.com/u/58223709/_WEB/ArduCopter.hex
Here is the 3.1.5 hex File for Hexa...
I had to use APM Planner on my mac to get it to upload... I was getting the same error with my Win Machine.
Thanks.
Fantastic - thank you very much!
AC3.3-rc1 is out (Pixhawk and other fast CPU boards only) and includes an increased accelerometer range (16g vs previous 8g) which may help. If someone here has a pixhawk or similar and is comfortable taking on the risks of trying a beta testing release, could you give it a try and report back if it improves things?
As a bit of a recap, it looks like from the comments here that most people are suffering with high vibration. The only solutions I can suggest that could help immediately are:
1. try and reduce the vibrations in the frame
2. try changing the vibration dampening mechanism (maybe try using the 3M vibration dampening foam)
3. try reducing Throttle Rate P (don't go lower than 2.0)
4. try reducing Throttle Accel P and I (don't go lower than P:0.25, I:0.5)
Rob had a look at the filtering between AC3.2.1 and AC3.1.5 and could not spot any differences. If someone has dataflash logs of two back-to-back flights which show that AC3.1.5 works better than AC3.2.1 that would be greatly appreciated. I know that's a lot to ask but it would help out.
Randy, can you explain what the Throttle Rate and Throttle Accel parameters exactly do?
Today I reduced Throttle Accel P and I (to 0.3/0.6) and Throttle Rate (to 4) and the pulsing motors disappeared! Alt Hold behavior was still quite bad, but maybe it was because of the strong wind (24 kts): After roll or pitch commands the cuad changed altitude quite badly (some meters).
Throttle Accel 0.3/0.6; Throttle Rate 5:
Quad specs: 800g weight, 310mm size, 1100kV motors, 8x5 props, 4S 2200mAh battery, APM 2.5 w/o GPS, Firmware 3.2.1.
All the best, Markus
2015-04-13 NoPulsingBadAltHoldWindy.bin
Now here what I did.
Model: X quad. 850kV motors running on 4S with 10x4.5 props.
1. Disabled GPS at all.
2. On 3.2.1 firmware (binary log), made a couple of back and forward flights, then a short trip round and then did still hover.
Overall performance was satisfactory, but copter had that feeling that something's not right. PID algorithm should give swift and smooth adjustments. This one had feeling of analog servo working with bad bearing. You could call it smooth twitching.
On long forward accelerations there was slight "dive".
3. Flashed to 3.1.5, disconnected GPS and compass.
Did all the same tests. Well, I don't know what magic was used to write 3.1.5 but you should use it again. All elevation changes were smooth and altitude hold was solid without twitches. Long forward run did give me a bit "dive", but this could be airframe dependent effect.
Might be important, that altitude gain and descent seemed to me much more calm (I mean on full throttle down, copter was descending slower than on 3.2.1) than on 3.2.1 (could be somehow connected to sensor resolution, past and present).
That's pretty much all.
p.s. I think 3.1.5 doesn't even need EKF, just add that splendid features like RSSI scaling, GPS controls, etc, not harming copter behavior, and maintaining compatibility and you need nothing more.
2015-04-13 18-49-43 3.bin
2015-04-13 19-26-07 5.log
No problem at all. I only need 1.5 hour for battery to charge.
I'll make 3.2.1 log and then 3.1.5 log. What kind of flight is preferable?
I'd suggest:
1. Hovering in alt hold.
2. Linear flight "forth-back"
3. Else?
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