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Old Apr 18, 2014, 03:02 PM
mutski
Fairbanks, AK
Joined Jan 2011
1,169 Posts
Discussion
Naza M failure

My Q450 quad with Naza M controller keeps falling out of the air, and I'm about out of ideas. Any help diagnosing the problem would be welcome!

Here are several video clips to illustrate the problem:
Naza M Crash Compilation - Help diagnose the problem! (1 min 49 sec)


Here is my setup:
Naza M with GPS; I generally fly in Attitude mode
NazaGPS on 6 cm bamboo mast
HK Q450 frame with integrated batter-ESC connections
Turnigy Plush 25 amp ESCs
NTM Prop Drive 28-26 motors
3S 4000 MAH 30C lipo
APC 8x3.8 slow fly props
HK Mini OSD with GPS, flashed to CL-OSD, GPS powered from Turnigy UBEC
12V LEDs powered straight from flight battery
Immersion 600 mw 5.8 ghz Vtx, powered from flight battery
Sony SuperHad FPV cam, 12V powered from flight battery
Keychain camera 808#16, powered from UBEC
Spektrum AR7010 rx with DORA for RSSI
Dx6i modified to take patch antenna
Alternate EZ-UHF 8 ch lite rx with SisHobby DAC for RSSI

Loss of control has occurred with both high and low Lipo voltage. Hovering, I noticed at below 11v, quad becomes unstable rotating clockwise, OK rotating counterclockwise. On sudden throttle increase, front right motor dipped. After replacing and calibrating ESCs, the left rear motor now dips. The quad still loses power and drops out of the sky. The low-voltage cutoff is shut off in both the ESC and Naza M programming.

I have tried
Replacing the antenna mount and antenna on my Dx6i
Switching from Spektrum to EZ-UHF
Reprogramming ESCs
Buying new Lipos ($250, ouch!)
Replacing ESCs
Calibrating ESC throttles

Still problems. I'm about to replace the Naza M with a KK2.
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Old Apr 18, 2014, 04:34 PM
Registered User
Canada, ON, Brampton
Joined Nov 2012
419 Posts
The only thing I noticed is the voltage on your OSD seems low. Not sure how accurate the reading is, but check it with a voltmeter if you haven't.

I have run my batteries down on a 5+ pound HEX to about 3.5 V/per cell and never lost control but it just looks like your voltages are a bit on the low side when the loss of control starts.

Other than that its difficult to diagnose the loss of control without being there.
Have you checked motor bearings as maybe a bad bearing is causing drag that may be drawing too much power and causing a faster than normal discharge.

Are you sure the batteries are actually charging properly? How many MA are going back in compared to how long you fly?

Just some thoughts...
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Old Apr 18, 2014, 09:26 PM
mutski
Fairbanks, AK
Joined Jan 2011
1,169 Posts
I'm using four separate chargers, also bought several new Hyperion batteries. My KK2 quad isn't having troubles; same.setup exactly except for the controller. I used to turn home at 10.6V and never had trouble landing. I made it back once at 9.2V after misjudging the return trip. I had full control till it.landed though not enough power to cushion the landing. I'm not sure about motor bearings, but all four spin freely, none.feels particularly loose.
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Old Apr 19, 2014, 06:24 PM
Registered User
Canada, ON, Brampton
Joined Nov 2012
419 Posts
Another Suggestion

I watched your videos again and the only other observation was with your RSSI signal strength. One of the vids shows the RSSI drop down to 30% for a short time so I am wondering if your receiver is going into brown out due to low voltage spikes.

It looks like the issue comes up when you are getting low on main battery volts and it is POSSIBLE that due to the amount of juice the motors are taking there isn't quite enough left for the Rx. As the motors demand less volts as you adjust your pitch and roll then the Rx can come back on line.

Once the Rx goes into brown out it takes a few seconds to come back on line and allow regaining control.

That could account for momentary loss of control and then regaining it shortly after.

Have you ever noticed if your Rx LED is blinking when you crash land? If it is then that would indicate a loss of signal and then a re-bind.

Do you have "Fail Safe" set for loss of signal? If yes then the quad should perform a Return to Home. If not then it could just drop out of the sky.

Some other things to check if you haven't already.
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Old Apr 20, 2014, 12:09 PM
mutski
Fairbanks, AK
Joined Jan 2011
1,169 Posts
I initially thought RSSI was the problem, and it may be that more than one thing is going on here. The problem started when I was using a Dx6i modified to take a patch antenna. After noting low RSSI associated with crashes, I inspected the tx and saw the center pin on the antenna mount was pushed in a bit, and wondered if it wasn't making solid contact. However, I replaced the mount and antenna, then switched to EZ-UHF; neither fix solved the problem. When I was trying to figure out what was wrong, I tried just hovering closeby. I noticed that when I tried to spin clockwise, the right front motor would dip. When I spun counterclockwise, it was stable. Likewise, when I gave sudden throttle, the right front motor dipped. Hover, the quad was still responding to the controls. It doesn't seem to respond when it falls out of the sky though - just loses power and coasts to the ground. In the night flight on the video, I noticed the voltage on the OSD rose after it quit responding while RSSI was 100% throughout.

The problem does seem related to low voltage, and the critical voltage has been creeping higher over time. When the quad was new, I headed for home at 10.6V and often landed with no problems at 10.4 or 10.5V. I have video from a flight where I misjudged the return trip and made it back with 9.2V and still had full control using the Spektrum radios. When I first started having trouble, it seemed like the problem started around 10.6V. Then 10.8V. Now it's getting into trouble above 11V.

Maybe I go back to the idea of bad motor bearings? When it's working, this quad flies noticeably smoother than my KK2 quad (exact same setup except for the controller), which I flew down to 10.4 volts a couple of days ago for comparision. It would be a lot of work, but I could trade controllers between the two quads and see if the problem transfers. I also have a spare KK2 board; I'm on the verge of installing it on the Naza quad.

I do have RTH set up, and it has worked several times when I've flown out of range. I've reprogrammed it a couple of times in the course of switching radio systems. It engaged on my dining table when I turned off the tx with propellers off (accidental test).

Quote:
Originally Posted by Sundayflyer32 View Post
I watched your videos again and the only other observation was with your RSSI signal strength. One of the vids shows the RSSI drop down to 30% for a short time so I am wondering if your receiver is going into brown out due to low voltage spikes.

It looks like the issue comes up when you are getting low on main battery volts and it is POSSIBLE that due to the amount of juice the motors are taking there isn't quite enough left for the Rx. As the motors demand less volts as you adjust your pitch and roll then the Rx can come back on line.

Once the Rx goes into brown out it takes a few seconds to come back on line and allow regaining control.

That could account for momentary loss of control and then regaining it shortly after.

Have you ever noticed if your Rx LED is blinking when you crash land? If it is then that would indicate a loss of signal and then a re-bind.

Do you have "Fail Safe" set for loss of signal? If yes then the quad should perform a Return to Home. If not then it could just drop out of the sky.

Some other things to check if you haven't already.
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Last edited by mutski; Apr 20, 2014 at 12:17 PM.
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Old Apr 20, 2014, 01:42 PM
Registered User
Canada, ON, Brampton
Joined Nov 2012
419 Posts
Maybe the DX doesn't play well with a patch antenna. I would suggest getting a friend to help you perform a ground range test.

Are you sure the TX patch antenna is connecting to the TX output securely?

Take the props off and find an open field than get your helper to operate the sticks in a predetermined fashion and start walking with the quad. You should get several hundred feet on the ground especially with a patch antenna pointed at the model. If that works while the antenna is pointed at the model then try moving left or right of the "TX beam" and see if there is a sudden drop out. The TX should be held in the same position throughout these tests.

Also have the TX operator watch the RSSI signal strength on your monitor. If that all tests good then at least you know the TX and antenna is working correctly.

It still seems like there is a large voltage drop caused either by a bad motor, loose prop or bad solder joint on the main board of the quad.

Keep at it and something will show up. These things don't glide very well (like a brick!) so it is good to keep looking for something wrong.
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Old Apr 20, 2014, 01:47 PM
Registered User
United States, CA, Azusa
Joined Mar 2014
2,407 Posts
Wow seriously? Why do you people keep buying DJI crap?

Every other thread is about a fly away or losing control.

People telling you to not have a cell phone in your pocket, stay away from power lines, don't have your battery cables 1/5 inches from your FC. What a joke!!!

Don't know how to help. Did you try jumping up and down and spinning around twice before plugging in your battery?

Want to fix your problems? Get a different FC.

Sorry, had to vent. I feel sorry for you guys...

Flame away.
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Old Apr 20, 2014, 03:06 PM
mutski
Fairbanks, AK
Joined Jan 2011
1,169 Posts
I've lost control and crashed at close range with EZUHF and a tx that's flown my Easystar II almost 2 miles with no trouble. Also used two Spektrum transmitters and 3 different with the AR7010 rx and had trouble with the Naza but not my KK2. I don't think its the tx. It has to be Naza M, ESCs or motors.
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Last edited by mutski; Apr 20, 2014 at 03:11 PM.
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Old Apr 20, 2014, 03:20 PM
mutski
Fairbanks, AK
Joined Jan 2011
1,169 Posts
Quote:
Originally Posted by mattjk View Post
Wow seriously? Why do you people keep buying DJI crap?

Every other thread is about a fly away or losing control.

People telling you to not have a cell phone in your pocket, stay away from power lines, don't have your battery cables 1/5 inches from your FC. What a joke!!!

Don't know how to help. Did you try jumping up and down and spinning around twice before plugging in your battery?

Want to fix your problems? Get a different FC.

Sorry, had to vent. I feel sorry for you guys...

Flame away.

So which FC with RTH?
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Old Apr 20, 2014, 11:05 PM
Registered User
Auburn, CA
Joined Feb 2009
171 Posts
Would Xaircraft SuperX be a good choice?
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Old Apr 21, 2014, 01:03 AM
Registered User
United States, CA, Azusa
Joined Mar 2014
2,407 Posts
It's what I use now. I love it.

I've purposely done things to trip it up like do the compass calibration indoors and ran fly near power lines. Still flies great.
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Old Apr 21, 2014, 10:35 AM
Registered User
Auburn, CA
Joined Feb 2009
171 Posts
That's good to know mattjk, probably the direction I'm headed with my next build. I'm currently flying a Naza M V1 with correct FW, and it has been flawless, but as I move up in frame size, add-ons, and cost, all the Naza stories are starting to making me nervous.
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Old Apr 21, 2014, 12:25 PM
Registered User
United States, CA, Azusa
Joined Mar 2014
2,407 Posts
Quote:
Originally Posted by Bilymac View Post
That's good to know mattjk, probably the direction I'm headed with my next build. I'm currently flying a Naza M V1 with correct FW, and it has been flawless, but as I move up in frame size, add-ons, and cost, all the Naza stories are starting to making me nervous.
I can't blame you. I live in a heavily fire hazard area. Last thing I need is to have a fly away and start a lipo fire. I'd be off to prison.

The last 3 guys that accidentally started a fire here are in jail now.


http://abclocal.go.com/kabc/story?id=9397521
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Old Apr 21, 2014, 01:04 PM
mutski
Fairbanks, AK
Joined Jan 2011
1,169 Posts
I just ripped out the Naza M. Hope to have my old KK2 working in a day or two. If it works with the KK2, I'm blaming the Naza M.
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Old Apr 21, 2014, 03:19 PM
Registered User
United States, CA, Azusa
Joined Mar 2014
2,407 Posts
Quote:
Originally Posted by mutski View Post
I just ripped out the Naza M. Hope to have my old KK2 working in a day or two. If it works with the KK2, I'm blaming the Naza M.
KK2 is great. I have the kk2.1 in a mini fpv quad.

I also have the Crius all in one Pro Ver1 with GPS. Haven't set it up yet but heard a lot of good things about it. It'll also do waypoints. Heck of a deal for under $100.
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