Replies to This Discussion

Permalink Reply by Markus Järve on November 5, 2012 at 11:48am

Just a friendly reminder. I too love to hear mother language on foreign forums :) 

• ▶ Reply

Permalink Reply by Steven Tisseyre on November 5, 2012 at 4:18am

Is anyone able to assist with a thread I commented on 2 weeks ago, I think it's been lost in the thread.

http://www.diydrones.com/forum/topics/arducopter-2-8-released?xg_so...

Every now and then the aircraft twitches and you hear a slight beep form one of the motor as it does so. It's a HexaCopter.

I'm hoping it'll just be a PID adjustment that someone can suggest or if there is something obvious in the logs if the twitch can be seen.

Any help would be appriciated as it does concern me a little when flying as this behaviour doesn't seem right.

Many thanks,

Steve

• ▶ Reply

Permalink Reply by u4eake on November 5, 2012 at 6:06am

Sounds to me like you get a sync issue between esc and motor.  Maybe try setting the esc's to high timing.

Another option might be that the esc's have some trouble with the high 490hz update rate.  Try setting RC_SPEED to 400 instead of 490.

Regards,

u4

• ▶ Reply

Permalink Reply by Steven Tisseyre on November 5, 2012 at 6:48am

Thanks U4, I will reduce the ESC timing to 400, will this affect anything else?

The ESCs are all jDrones 30A, how does one check / change their timings ?

• ▶ Reply

Permalink Reply by Vernon Barry on November 5, 2012 at 7:14am

The ESCs are all jDrones 30A, how does one check / change their timings ?

Read the manual that came with the ESCs. Remember that little piece of paper that came in each static bag? The one that nobody ever reads and throws away.

It should be exactly the same as this for the 20 Amp. (FYI< these ESC are rebranded all over the place such as RC Timer, Jdrone, 3DR, etc..)

http://stuff.storediydrones.com/ESC%20Manual.pdf

Programmable Items:

6. Timing：Low / Medium / High, default is Low.

Usually, low timing value can be used for most motors.

 

 

• ▶ Reply

Permalink Reply by Steven Tisseyre on November 5, 2012 at 7:46am

LOL, Vernon, I'm a bloke, I never read instructions that comes with toys :-)

In all seriousness I don't remember receiving papers with the ESCs, however your link is very useful.

As timing by default is LOW, it would appear that lowering to 400 will help as suggested.

Think I will buy one of these to check all the ESC are as they should be.

http://www.hobbyking.com/hobbyking/store/%5F%5F29330%5F%5FTURNIGY%5...

Thanks again for your help.

• ▶ Reply

Permalink Reply by Vernon Barry on November 5, 2012 at 8:17am

Yes, rather than just saying RTFM, I tried to give you a little more info by providing the instructions in case you didn't have them and also show that particular ESC firmware is very common between several ESCs in that range.

 

Also, FWIW, I use SimonK firmware on mine with great results. IMHO, this is the better route (journey, as you would would say), to use the alternate firmware.

http://www.rcgroups.com/forums/showthread.php?t=1513678

 

This is your ESC internal programming pinout:

• ▶ Reply

Permalink Reply by u4eake on November 5, 2012 at 11:00am

Don't confuse esc timing with the update rate of the apm -> esc signal.

Esc timing is usually low by default and can be set to medium or high.  High pole count outrunners (like we mostly use) usually feel better with high timing.  This is the timing of the current pulse that the esc send to the motor coils, kinda like the ignition timing on a combustion engine.  Slightly wrong timing can make the engine run a bit hesitating at certain rpm's.

Update rate (RC_SPEED parameter) is the frequency at which the APM sends commands to the esc's.  By default it does this 490 times per second (490 hz).  A lot of esc's can handle this just fine.  Some have trouble with it and get confused or just won't work at all.

Reducing this will slightly affect stability and agility (as the esc's don't get updated commands as often).   But if it gets rid of the glitches, I think it's worth it.

• ▶ Reply

ModeratorPermalink Reply by Graham Dyer on November 5, 2012 at 5:01am

@Steven, a single motor beep/twitch can't be sorted out with PID's. If you enable 'motors' in the logs (see the wiki) you might be able to see a twitch in the output to a motor but if it's something like wiring, connection or a faulty ESC then it won't show up in the 'motors' part of the log. The twitch though should show up in if 'raw' is enabled in the logs as a spike in the gyro or accellerometer logs.

• ▶ Reply

Permalink Reply by Steven Tisseyre on November 5, 2012 at 5:35am

Many thanks for the reply Graham, most helpful.

I shall enable the suggested logs and see what that produces. I wish I knew which motor was twitching if indeed its the same one each time as it happens so fast.

I could then focus a little on what the cause may be. It's difficult fault finding these issues if you don't know where to start ;-)

This is a typical twitch - http://youtu.be/q_ECxFx8hsY

Thanks again,

Steve

• ▶ Reply

Permalink Reply by Markus Järve on November 5, 2012 at 6:55am

It is exactly what I have been seeing on my new quadcopter. I thought that it was problem with my drivers, but since there are at least 2 people with their quads doing random twitching, it seems to be the problem on the code. 

• ▶ Reply

Permalink Reply by AS on November 5, 2012 at 12:39pm

Hi Markus!

I had twitching, that proven to be a loose cable on my RX. Have you tried to re-check all the wiring? Just my two cents...

Regards

• ▶ Reply

• ‹ Previous
• 1
• …
• 37
• 38
• 39
• 40
• 41
• …
• 113
• Next ›
• Page