initial THROTTLE problem in any modes

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I loaded my 1280 mega board with the latest v2.5.3 firmware with the APM planner

The problem which I am facing is that when I arm motors and increase throttle 
till just the position where the motors starts spinning the motors are spinning 
at high speed where as it should run slow and increase according to the 
increase of the throttle stick..

I calibrated each ESC manually they start well at that initial point..

Tried the automatic calibration , there also the motors starts spinning at a 
normal rate in the initial position..

What may be the problem...??

Original issue reported on code.google.com by nemo4...@gmail.com on 6 Apr 2012 at 9:36

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I wonder if maybe you have the end points on the radio set to be very close 
together or maybe something has gone wrong with your radio calibration in the 
APM Mission Planner.

When you go through the AP Mission Planner's firmware screen and clicked on the 
APM Setup button and do the radio calibration, what are the min and max 
throttle values that you see.  In the attached picture you'll see mine which 
are 1108 and 1933.  Yours should hopefully be somewhere in that range.

Original comment by rmackay...@gmail.com on 10 Apr 2012 at 2:30

Attachments:

• RadioSetupExample.png

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When your throttle is high, the PWM value should be high.

I've been flying all weekend with this code and the throttle is OK. It's your 
radio setup that must be the issue.
Note that the throttle is not a 1:1 pass through from your radio. It's 13% to 
85% output scaled to your stick. That maximizes the range of effective control 
for hovering while giving you headroom at the top for stability control.
Jason

Original comment by jasonshort on 11 Apr 2012 at 5:48

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Hello,

I have a similar issue.
Reading Jason's post I realised what could be the problem.
Since my quad hovers around 15% (I know it's over powered ...) and since APM 
throttle is scalled to begin at 13% I wonder if there is a way to change that 
13% to 85% output range.

Regards,
Vitor

Original comment by vitor.ro...@gmail.com on 16 Jul 2012 at 2:27

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I am experiencing a similar problem.  Motors spin up way too fast at the low 
end of the throttle setting and lack range from low to high.  I have calibrated 
the radio numerous times as well as trying different settings on the 
transmitter.  If I go direct from transmitter to esc's there is a good and 
controllable range of speeds.  It is as if the cut in point on the motors is 
halfway up the speed range at the lowest throttle range when going through the 
ardu.  

Original comment by jim29686...@gmail.com on 4 Dec 2012 at 10:41

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[deleted comment]

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I have the same issue running V2.8 R3 on a cirus AIO pro 2.

Good linear throttle when ESC's are hooked direct to RX but motors cut in at 
half then are at full power by mid stick and run rough at high stick when 
through the flight controller.

ESC calibration via the flight contoller does not work corectly (30a RC imer 
ESC's flashed with simonk)

Radio calibration seems ok in Mission Planer 

Original comment by shan...@aol.com on 19 Feb 2013 at 11:09

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@shan...@aol.com
Try reducing THR_MIN
But be aware that you have to set a THR_MIN that mantains your motors spinning 
(with just a little throttle input).
This is because if your multirotor is on a high rate descent with no throttle 
and you set your THR_MIN too low the propellers will rotate in oposite 
direction of normal spin and there is a great possibility that your ESCs can't 
oppose this and in that case it's a crash for sure.
I reduced my THR_MIN to 50 but that could be just too low for you.
Regards,
Miguel

Original comment by vitor.ro...@gmail.com on 19 Feb 2013 at 11:28

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Thanks Miguel.

is that in the parameter settings on left side of the Mission planer or a code 
change via the Terminal tab ?

Original comment by shan...@aol.com on 19 Feb 2013 at 12:36

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@shan...@aol.com,
You're welcome.
I set THR_MIN via Configuration tab -> Advanced Params -> Adv parameters list
Regards,
Miguel

Original comment by vitor.ro...@gmail.com on 19 Feb 2013 at 12:42

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I also am experiencing problems with this. I have reduced THR_MIN to some 
effect but still cannot find a comfortable range. Going up is easy coming down 
is not!! I have ewad somewhere that there is a THR_MID parameter. However it 
must be well hidden.   

Original comment by colinh...@gmail.com on 5 Jun 2013 at 10:36

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Closing all issues on the old issues list by marking them WontFix.

If this is still a valid issue please re-raise it on the new GitHub issues 
list: https://github.com/diydrones/ardupilot/issues

Thanks!

Original comment by rmackay...@gmail.com on 21 Jul 2013 at 2:14

• Changed state: WontFix