Question about fail safe and signal loss


OK, so everything is working fine on the bench, but all night I've been wondering WHY??

I've been through the manual and I don't see anything about putting distance between the Tx and Rx when binding :cold:

From day one, I've always bound them right next to each other and it obviously worked as I've been flying with the new receiver, but wasn't able to get the set the RTH until sochin chimed in with the 10ft thing :confused:

Not complaining as I'm more than happy that it's finally working, but I just don't get it :dejection:
 


sochin33

Member
OK, so everything is working fine on the bench, but all night I've been wondering WHY??

I've been through the manual and I don't see anything about putting distance between the Tx and Rx when binding :cold:

From day one, I've always bound them right next to each other and it obviously worked as I've been flying with the new receiver, but wasn't able to get the set the RTH until sochin chimed in with the 10ft thing :confused:

Not complaining as I'm more than happy that it's finally working, but I just don't get it :dejection:

Hey Snake
What wasn't clear to me from the previous posts on this thread was whether or not you were flipping your mix switch to FS AFTER you pulled the bind plug and BEFORE you turned on the radio. If you were doing this and still not getting a bind then in fact it probably was the 10ft thing that was the issue. It sounds like this was the case.
As to why, I'm not sure …. maybe there could be stronger multi path interference when you are closer to Rx ?
 

Hey Snake
What wasn't clear to me from the previous posts on this thread was whether or not you were flipping your mix switch to FS AFTER you pulled the bind plug and BEFORE you turned on the radio. If you were doing this and still not getting a bind then in fact it probably was the 10ft thing that was the issue. It sounds like this was the case.
As to why, I'm not sure …. maybe there could be stronger multi path interference when you are closer to Rx ?


Yes, I had tried binding with the Mix switch in both positions (on and off) before turning on the radio numerous times and no dice.

On this last bind, I did it with the Mix switch on and the only thing I did differently was put some distance between the Tx and Rx and it just worked :black_eyed:
 

OK, it seems I have a new issue :upset:

I recently installed a new Photoship One landing gear set and a 2-axis brushless gimbal.

Upon taking the first test flight, the controls felt very unstable :dejection:

I figured it might have sumthin to do with the battery being moved from the top to the bottom, so I tried different locations and even went as far as to take the landing gear off completely, but the problem still persists :confused:

Earlier today, I did a few test flights while making changes one by one.

1) Re-Calibrated Tx Controls
2) Re-Calibrated GPS Compass
3) Re-Calibrated IMU
4) Re-Positioned Rx away from the NAZA USB doohicky
5) Covered the sides of the NAZA with electrical tape
6) Held frame down as I powered up to full throttle and moved the right stick in all positions to check motors, blowing crap all over my office
7) Checked all motor wires and wires leading into the NAZA


Here's a short video I made showing the issue:

https://www.youtube.com/watch?v=rNvph1gUA1A

As you can see, the sticks are still very responsive in both ATT and GPS modes, but instead of holding position, she drifts around and drops altitude suddenly while still staying somewhat level.

Open to suggestions at this point.
 

sochin33

Member
OK, it seems I have a new issue :upset:

I recently installed a new Photoship One landing gear set and a 2-axis brushless gimbal.

Upon taking the first test flight, the controls felt very unstable :dejection:

I figured it might have sumthin to do with the battery being moved from the top to the bottom, so I tried different locations and even went as far as to take the landing gear off completely, but the problem still persists :confused:

Earlier today, I did a few test flights while making changes one by one.

1) Re-Calibrated Tx Controls
2) Re-Calibrated GPS Compass
3) Re-Calibrated IMU
4) Re-Positioned Rx away from the NAZA USB doohicky
5) Covered the sides of the NAZA with electrical tape
6) Held frame down as I powered up to full throttle and moved the right stick in all positions to check motors, blowing crap all over my office
7) Checked all motor wires and wires leading into the NAZA


Here's a short video I made showing the issue:

https://www.youtube.com/watch?v=rNvph1gUA1A

As you can see, the sticks are still very responsive in both ATT and GPS modes, but instead of holding position, she drifts around and drops altitude suddenly while still staying somewhat level.

Open to suggestions at this point.

I wonder about what goes on with the GPS sats in that urban environment, so close to buildings, etc.
Also interference with your Tx.
At any rate, doesn't the NAZA control altitude by barometric means ? I've never been certain of this.
I take it that when you took off, you had more than 6 sats ?
Could you try the same test out of town, in an open field ? Those altitude drops are not OK !
 

Benjamin Kenobi

Easy? You call that easy?
I'm not sure what the problem is. Everything looked fine to me! Remember GPS accuracy is only +/-2m horizontally and +/-0.5m vertically. It looked like it was within those parameters.

The one thing you didn't mention or change is the gains you're using as these have the biggest effect on response and control.

Descending into your downwash does lead to dropping and you'll need to fight it. I tend to move in a direction whilst descending.

Your location was not ideal with a building reflecting GPS signals and a vehicle nearby with all its magnetic properties.
 

sochin33

Member
I'm not sure what the problem is. Everything looked fine to me! Remember GPS accuracy is only +/-2m horizontally and +/-0.5m vertically. It looked like it was within those parameters.

The one thing you didn't mention or change is the gains you're using as these have the biggest effect on response and control.

Descending into your downwash does lead to dropping and you'll need to fight it. I tend to move in a direction whilst descending.

Your location was not ideal with a building reflecting GPS signals and a vehicle nearby with all its magnetic properties.

I have never had to fight the controls to keep my craft at constant hover altitude as Snake stated in his video. It looked like he was just trying to hover, not recover from a rapid descent, but agree with Ben if this followed a rapid descent. I also agree that things looked fine in the video with the exception of his comment about fighting with the controls.
Snake, if you put your craft at say , 5 meters altitude in GPS and let it hover, does it drop ? How far ?
 

I wonder about what goes on with the GPS sats in that urban environment, so close to buildings, etc.
Also interference with your Tx.

I've been flying for well over a year in this same spot without issue.

At any rate, doesn't the NAZA control altitude by barometric means ? I've never been certain of this.

From what I've read, yes.

Apparently, sunlight can sometimes cause an issue and a quick fix that others have done is cover the NAZA with black electrical tape.

Seemed kinda hokey, but I tried it anyways with no change.

I take it that when you took off, you had more than 6 sats ?
Could you try the same test out of town, in an open field ? Those altitude drops are not OK !

Yes, I usually wait for flashing green before taking off as I did with this video.

However, it shouldn't really matter.

I've taken off in either mode before when I was too impatient and just let it acquire in the air.

When in GPS mode with center sticks, it would always hold the same position in the air.

When in ATT mode with center sticks, it would drift with the wind, but always hold altitude.

Here are a few old videos from the same spot flying as it should:

http://www.youtube.com/watch?v=smXzeZUB-Gc

http://www.youtube.com/watch?v=4IcjCff5Lgk

http://www.youtube.com/watch?v=iQdGNxIipk4




I'm not sure what the problem is. Everything looked fine to me! Remember GPS accuracy is only +/-2m horizontally and +/-0.5m vertically. It looked like it was within those parameters.

Take note of 1:38 in this video.

https://www.youtube.com/watch?v=rNvph1gUA1A

All sticks are centered and she drifts and loses altitude randomly until she touches down at the very end (definitely NOT normal)

The one thing you didn't mention or change is the gains you're using as these have the biggest effect on response and control.

Never touched the gain settings.

They've been the same since it was built in September of 2012.


Descending into your downwash does lead to dropping and you'll need to fight it. I tend to move in a direction whilst descending.

It happens at any altitude

Took it up to about 100 feet yesterday and it behaved the same way.

Your location was not ideal with a building reflecting GPS signals and a vehicle nearby with all its magnetic properties.

See videos above.

Even in ATT mode, it should at least hover and hold altitude as it has before.



Anyways, I've been going over in my head the changes I've made between my last issue free flight and now.

1) Re-binded the AR8000 to pre-set RTH

After doing this, I immediately noticed that when powering up, the NAZA would flash orange and take an abnormally long time before it flashed red/green.

It had always instantly started flashing red/green upon powering up before.

When I first noticed this happening, it had been sitting indoors with the A/C blasting, so when FlyGirl mentioned it probably having to warm up in post #55, I figured no big deal, however, over the last year of flying in all weather conditions including freezing cold, not once did it ever do this :confused:


2) De-soldered main power wire Traxxas plug and re-soldered using a length of twised wire and a JST plug for the brushless gimbal.

I doubt this would cause an issue, but I guess I should mention the red and black wire did touch for a second while I was soldering the gold terminals for the Traxxas plug.

I thought perhaps the twisted wire I added was somehow causing interference, so I de-soldered and re-soldered as it was and the flight issue still persists.

3) I removed the old landing gear and installed a new Photoship One landing gear with gimbal mount.

At first, I though perhaps having the battery relocated to the bottom was the issue, but even after removing the landing gear altogether and putting the battery back on top, I still have the same problem.



That's pretty much where I am at this point :dejection:

I have a feeling it's in internal baro issue with the NAZA, but I'm trying to diag every possible alternative before going that route :cold:
 


You said that you move your batteries. Did you refigure your COG?


I recently replaced my old generic landing gear with this Photoship One setup:

photoshiponelandinggear5.jpg


photoshiponelandinggear12.jpg


That's when the battery was moved from the top plate to the bottom rear to compensate for the front mounted gimbal.

After my first flight attempt with this setup, that's when I noticed the instability and tried moving the battery back to the original position on the top plate, but it still felt funky, so I pull the whole landing gear setup completely until I get the flight issue figured out :cold:

I'm currently uploading another video from earlier today (1.5GB is taking forever on this connection)
 

sochin, you tha man!! :cool:

Before attempting to change the gear switch settings, I decided to try re-binding one last time and put some distance between the Tx and Rx (sumthin I haven't done before) :cold:

With the Hex in one room an me with the Tx in another, I did a re-bind with the RTH switch flipped and it worked!! :highly_amused:

Welcome to the world of RF. The transmitter was swamping the receiver.
 



I don't know Snake.... Maybe it's the difference between my NAZA Lite and your NAZA (I forget which you have) but everything I saw in the vid looks normal to me.

Are you saying that twitchy handling, drifting and random altitude changes are normal with the NAZA Lite?

I'm not familiar with the Lite's flight characteristics, but I'm running the old NAZA M and it's definitely NOT normal :upset:

Compare my last video to this one I made a few weeks ago (fast forward to about ~3:40)

https://www.youtube.com/watch?v=6_04BvGmbcg


Take note of when I switch between GPS and ATT modes

As you can see, it holds position like a rock in GPS mode even in high wind.

In ATT mode, it drifts with the wind, but still stays level and holds altitude as it should.

No twitching, no random altitude drops/gains and I don't have to fight with the throttle to keep it in the air.

That's the way it has always worked for me since day one, so something is definitely wrong with it now.

I'm thinking about just swapping out the motors since it's the easiest thing to do, but again, I'm open to suggestions :cold:
 

sochin33

Member
Compared to my NAZA M V2 550, yours definitely seems to drift more in altitude. It looked to me as though your altitude drift is on the order of 5 feet or so ? Mine easily stays within a foot or less.
As for the horizontal drift and what you described as "twitchy" .... This seems comparable to mine. Occasionally I see some TBE like yours but not always. Have you corrected at all for magnetic declination by slightly rotating your GPS puck ?

Sorry I can't help more !
 

Have you corrected at all for magnetic declination by slightly rotating your GPS puck ?

I haven't touched the GPS puck since I installed the new mast weeks ago.

That was before the test flight in post #76, which was trouble free.

I doubt it has anything to do with the GPS because I'm having the same flight issue in either GPS or ATT mode

The twitchyness I'm referring to is when I'm flying with the right stick only.

It just feels like it's gunna dip or dive at any moment :upset:

With the left stick at 50%, it shouldn't lose or gain altitude regardless of what I do with the right stick in either mode.

I know it's hard to tell going by the video, but it's nowhere near as smooth and solid as it once was :cold:
 

Benjamin Kenobi

Easy? You call that easy?
I admit my NAZA-M is solid and doesn't drift or drop at all. It just sits there so I don't know what's going on with yours. Something has changed but I don't know what. Hope you figure it out mate.

What gains are you using?
 


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