550 Motors Pulsing

[JoeBob]

I'm sorry this video is 9 minutes long. Every time I'd get to something that I wanted to cut, something different would happen. If you want to skip to minute 8:40, the last series of pulses is the most dramatic.

Summary:

At first, the throttle is VERY touchy. No response to input until you get to halfway and then it blasts up. Once it's been pushed to the max and pulled back down, sensitivity to adjustment is restored. Is this normal? Take-off in full power?

In GPS and ATTI modes, the motors will run normally until I get over 50%. Above 50% the motors will start pulsing; accelerating and dropping over and over. Switching between ATTI and GPS does not change the pulsing. Switching to Manual returns throttle response to normal. Dropping below 50% in GPS or ATTI returns throttle response to normal. (You can determine the Modes in the video by the LED reflected on the locker.)
Is this an artificial condition that I've created by clamping it to the bench?


Above 60% in GPS or Atti, it runs normal for a while, and then starts pulsing. Sometimes I loose the double green blinks from the FC and get single greens. (Same for yellow in ATTI) It makes this change with no input from the radio. Dropping the throttle below 50% and switching back to GPS or ATTI restores normal double blinking.

No heat build up in any ESC or motor. The motor over the table is slightly warmer, probably because of reduced air flow.
The GPS puck is taped flat on top of a roll of solder for now to keep it from vibrating out of position. Waiting on parts to repair the mast from my last gravity party.
Since it runs true in Manual, is it safe to eliminate shorts and other electrical issues?

The loud vibration noises are the two legs flexing enough to get off the table and then hitting it. One new prop is not balanced.

Stock DJI 550
Spektrum DX9
AR8000

View attachment 17994

Any and all suggestions welcomed.
Thanks,
Joe

 

[PeteDee]

Have you tried rebinding your radio, tried making a new model setup?

And get rid of your voltage protection.

Pete

 

[JoeBob]

Thanks Pete,

Re-Bind: The AR8000 and it's satellite both stay lit red; but I went through the binding protocol anyway.

There are entries in the Voltage protection fields, but VP is turned off.

Reading elsewhere, I'm thinking about re-soldering all the connection points to the 30A ESCs; but since it runs true in Manual mode, could an ESC connection really be the problem?

Thanks,
Joe

 

[soler]

"At first, the throttle is VERY touchy. No response to input until you get to halfway and then it blasts up. Once it's been pushed to the max and pulled back down, sensitivity to adjustment is restored. Is this normal? Take-off in full power?"

Yes this is normal to help you out of the ground effect.


"In GPS and ATTI modes, the motors will run normally until I get over 50%. Above 50% the motors will start pulsing; accelerating and dropping over and over. Switching between ATTI and GPS does not change the pulsing. Switching to Manual returns throttle response to normal. Dropping below 50% in GPS or ATTI returns throttle response to normal. (You can determine the Modes in the video by the LED reflected on the locker.)
Is this an artificial condition that I've created by clamping it to the bench?"

I think it is not straight on your table and it is trying to correct it's self, try with it flat to see if you get the same conditions

"Above 60% in GPS or Atti, it runs normal for a while, and then starts pulsing. Sometimes I loose the double green blinks from the FC and get single greens. (Same for yellow in ATTI) It makes this change with no input from the radio. Dropping the throttle below 50% and switching back to GPS or ATTI restores normal double blinking."

The double blinking is indicating that you sticks are not in the centre positions.

 

[JoeBob]

Soler:
"I think it is not straight on your table and it is trying to correct it's self, try with it flat to see if you get the same conditions"

I can see where you might think it's not flat, but I have pieces of minicell foam under the three points where I clamped it down. I also took care to get the GPS module level. But I'll run the test again and put a level to it first.

Thanks for the ground effect info.
Joe

 

[PeteDee]

So have you actually tried to fly this bird or only on the clamp setup?

Pete

 

[JoeBob]

Sometimes it flies great! About 35 flights now, usually with Landing Gear and GoPro.
But after 6 drops from the sky, and resultant repairs, I'm still trying to pinpoint why this F550 sometimes ignores radio input and drops. (At least it doesn't FlyAway.)

The test in this thread is follow up to this discussion:

http://www.multirotorforums.com/sho...50-Quadcopter!&p=160840&viewfull=1#post160840