Re: [Paparazzi-devel] SimonK ESC slow response problem

[Kadir ÇİMENCİ]

BTW , weight with payload is about 1.8 kg , and frame is quad..

2014-04-16 8:12 GMT+03:00 Kadir ÇİMENCİ <address@hidden>:

Hi Eduardo,

What is your motor/prop combination for hk blueseries 40amp.? Right now im using Quadrocopter motors with 10x4.5 and MK BlCtrl 2.0(firmware v0.31b) . But i guess this combination may have losses and im not happy with the flight time..

Kadir

2014-04-15 23:32 GMT+03:00 Eduardo Lavratti <address@hidden>:

Hi Sergey,
have you tested wii-esc firmware ?

Some time ago i  changed all my esc from simonk to wii-esc
Actually i only use  hk blueseries 40amp esc with wii-esc firmware (Complimentary PWM)
this is the best combination i ever tested.

On my little quad i use hk blueseries 20amp.

On 04/15/2014 04:52 PM, Sergey Krukowski wrote:

Hi guys!

Last time I had a chance to work a bit with different ESCs flashed with SimonK firmware and since it wasn't really plug and play or fast and furious as most comments in web say - wanted to share some experience.
First of all I tried 3 different rotorcrafts with 3 different motor sizes with 3 different ESCs:

ST4708 360KV with 15x5.5 propeller and Turnigy Multistar 45 Amp 6S LiPo
MK3638 700Kv with 13x4.7 propeller and ZTW Spider Series 30A OPTO 4S LiPo
CF2822 1200Kv with 10x4.7 propeller and Afro ESC 12Amp 3S LiPo

As far as the first rotorcraft was pretty large, it was pretty stable and I didn't really noticed any weird behavior.
However both other showed very weird frame oscillations mostly in horizontal frame positions. And there was no PID combination to find, that would remove these oscillations (was using ahrs_int_cmpl_quat with euler_int attitude stabilization).
The oscillations wasn't really large, didn't really impact horizontal position stability but the overall external flight quality was unacceptable.

The actual problem eventually was in SimonK firmware. Most of recently released versions (well, most likely ALL available to buy ESCs with SimonK firmware) have a poorly solved max output power limitation depending on commutation period (most probably because of atmega's calculation power lack). That is why on some motor/propeller/pwm command combinations it doesn't give enough power to motor, causing undershoot and therefore the weird oscillations I described.

The actual solution was to increase TIMING_RANGE1 and TIMING_RANGE2 values, so the firmware can give more power on lower rpms. But it should be care taken about that modification, because it can cause other problems, for example motor stall.

P.S.
Right now there is an other way of the max power limitation implemented under the tgy github, looks like it should work more stable on different motors/props/rpms than before.

Best Regards,
Sergey

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