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Oct 04, 2013, 05:18 AM
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Help!!! NAZA PWM outputs are not consistent at hover


Hi Team,

Need an urgent help on the following topic. I am doing a ground test to check the consistency of NAZA PWM outputs. More specifically,
1) hobbyking Quad-rotor 450 with naza is put on a lever ground.
2) activate naza, and only throttle goes to 50% for 5 sec, then go up to 60% for 5 sec, repeat for 2-3 times.
3) use salene signal analyzer to record the input (as shown below)

As you can see in the picture, motor 1&3 matches together, 2&4 matches together. However, there is a big gap btw the two pairs. I did the test 4-5 times and the same thing happened. Quite weird. Supposedly, all the outputs should have the same value.

Another thing I feel confused is the pwm reading of the 50% throttle is different between the first-time stay and the subsequent stays.

Any suggestions and comments are greatly welcome.

Alex

Last edited by gwfalcon; Oct 04, 2013 at 05:31 AM.
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Oct 04, 2013, 06:17 AM
Gyro, SimonK n call it a day:)
lockwood's Avatar
Im assuming it is strapped down or the propellers aren't on? Have you tried to fly it yet?
Oct 04, 2013, 07:14 AM
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Originally Posted by lockwood
Im assuming it is strapped down or the propellers aren't on? Have you tried to fly it yet?
Thank you for your kind reply.

I flied the quad before and it generally works well.

Yah, when I do the ground test, for safety, I remove the props and just the motors are running. but does it affect the pwm output??
Oct 04, 2013, 08:46 AM
Gyro, SimonK n call it a day:)
lockwood's Avatar
I think it does, I have tried hand tuning and even built rigs to tune my quads and always got mixed results, free flight is the best IMO. I think this is what you are getting as far as reading PWM out put. The naza specifically does not have a linear throttle, its algorithmic, for "smoother" take off/landing. Also at 50%throttle it is enabling the barometer which is sending signals based on what it assumes is free flight. If you individually calibrated your esc's with your transmitter and done the necessary TX calibrations through the naza and its hovering like it should I wouldn't worry much.
Oct 04, 2013, 10:01 AM
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BobRCnut's Avatar
Interesting scenario. I could understand the indications with props on, because I've seen cases where CW and CCW props from the same manufacturer have slightly different pitches, inducing a yaw effect that causes the NAZA to try to correct by driving two opposing motors slightly differently than the other two. Without props, though, it would seem that maybe the yaw correction is offset from center, or biased somehow. What happens to the pulse width if you move the rudder (yaw) stick then release it? This phenomenon may explain why some quads that fly perfectly will land with two opposing motors warmer than the other two.
Oct 04, 2013, 10:37 AM
SirEdward
blimppilot@ph's Avatar
Alex i got quite confused by your thread title... why would you call for help when your naza is flying well..

Anyway i don't know how and what procedure you made for this test but when I did the same thing i actually got around the same values from m1 to m6
Oct 05, 2013, 02:48 AM
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Quote:
Originally Posted by lockwood
I think it does, I have tried hand tuning and even built rigs to tune my quads and always got mixed results, free flight is the best IMO. I think this is what you are getting as far as reading PWM out put. The naza specifically does not have a linear throttle, its algorithmic, for "smoother" take off/landing. Also at 50%throttle it is enabling the barometer which is sending signals based on what it assumes is free flight. If you individually calibrated your esc's with your transmitter and done the necessary TX calibrations through the naza and its hovering like it should I wouldn't worry much.
Thank you for your kind sharing. I will try free flight later and update the measurement.
Oct 05, 2013, 03:01 AM
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Quote:
Originally Posted by BobRCnut
Interesting scenario. I could understand the indications with props on, because I've seen cases where CW and CCW props from the same manufacturer have slightly different pitches, inducing a yaw effect that causes the NAZA to try to correct by driving two opposing motors slightly differently than the other two. Without props, though, it would seem that maybe the yaw correction is offset from center, or biased somehow. What happens to the pulse width if you move the rudder (yaw) stick then release it? This phenomenon may explain why some quads that fly perfectly will land with two opposing motors warmer than the other two.
Very good point, man. I will calibrate the naza again and see whether I can get the signal improved. Many thanks!
Oct 05, 2013, 03:02 AM
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Originally Posted by [email protected]
Alex i got quite confused by your thread title... why would you call for help when your naza is flying well..

Anyway i don't know how and what procedure you made for this test but when I did the same thing i actually got around the same values from m1 to m6
Thank you for sharing your test result. I just want to make sure the naza is working truly well. Will update my test results soon.


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