Naza Lite GPS configuration

A

AirPix

Member
In the NAZA Lite mounting section (page 12 of the pdf manual) you have to input the x, y and z coordinates of the GPS antenna of the flight-ready multirotor. And there is a Notice that "You must re-configure if the ALL-UP-WEIGHT had been changed on your multi-rotor". Both items understood.

But in real-life, you're not always going to be flying with the camera (especially in the early testing phases) and you may be flying with batteries of different weights (higher or lower capacities or cell counts), so the all-up weight will change. HOW SENSITIVE is the GPS to weight change? Especially, I imagine, with changes in the "z" coordinate value? With a "properly balanced 'copter" changes in payload or battery weight will cause the value of "z" to change-- increase that weight, and the (absolute) value of "z" will increase (ie, -2 to -3), and vice versa with a decrease in weight. (depending on where the GPS is located, "x" and "y" may change, too, but let's ignore that for the time being)

Would it work to "set" the GPS z-value using a maximum battery and payload weight (assuming a light one-axis camera mount and a light point-and-shoot camera) even though you may fly with lighter batteries or no camera? Re-configuring the system for "minor" changes in weight (of a few ounces) could be a PITA.

I'm going to assume that the would apply only to flight modes that use GPS and not the simple "Atti" mode. And also assuming that the basic x-y balance is good.

Convoluted question... waiting for snow. :)

--Bill
 

T

Tahoe Ed

Active Member
AirPix said:
In the NAZA Lite mounting section (page 12 of the pdf manual) you have to input the x, y and z coordinates of the GPS antenna of the flight-ready multirotor. And there is a Notice that "You must re-configure if the ALL-UP-WEIGHT had been changed on your multi-rotor". Both items understood.

But in real-life, you're not always going to be flying with the camera (especially in the early testing phases) and you may be flying with batteries of different weights (higher or lower capacities or cell counts), so the all-up weight will change. HOW SENSITIVE is the GPS to weight change? Especially, I imagine, with changes in the "z" coordinate value? With a "properly balanced 'copter" changes in payload or battery weight will cause the value of "z" to change-- increase that weight, and the (absolute) value of "z" will increase (ie, -2 to -3), and vice versa with a decrease in weight. (depending on where the GPS is located, "x" and "y" may change, too, but let's ignore that for the time being)

Would it work to "set" the GPS z-value using a maximum battery and payload weight (assuming a light one-axis camera mount and a light point-and-shoot camera) even though you may fly with lighter batteries or no camera? Re-configuring the system for "minor" changes in weight (of a few ounces) could be a PITA.

I'm going to assume that the would apply only to flight modes that use GPS and not the simple "Atti" mode. And also assuming that the basic x-y balance is good.

Convoluted question... waiting for snow. :)

--Bill
Click to expand...

The GPS is pretty sensitive to the settings. As I add equipment, I always check my COG in ready to fly condition, and reenter them in Assistant. It never takes very long and I feel more comfortable flying. I also recalibrate my compass after every upgrade.
 

A

AirPix

Member
Then I will plan to start off doing that myself. It might even pay (time- & trouble-wise) to get a laptop or tablet for use with the multirotor. That would even be useful to review review photos and videos in the field.

I'm currently old-school with a nice desktop system...

Thanks.

--Bill
 

T

Tahoe Ed

Active Member
Better be careful you may end up with a iPad or Android device and a BTU. The app is great for at the field.
 

D

Dynamo

New Member
i have a naza lite all setup went well until motors wont arm
on bootup light sequence is normal until the end when i get 3 green instead of 4
then settles to blinking 2 red anyone got any ideas ?????
 

A

AirPix

Member
Tahoe Ed said:
Better be careful you may end up with a iPad or Android device and a BTU. The app is great for at the field.
Click to expand...
I may some day but for now I've got Naza Lite Flight Controllers which are non-Canbus, so I'll need a USB device with the Assistant Software on a laptop/tablet for field configuring. And one could have a gazillion other uses, too. I'll hit Search and see what folks are talking about and if I come up dry, I'll start a thread on 'puters.

--Bill
 


S

smackenzie

Member
Ohhh I did't know about the need to recalibrate GPS when AUW changes. I added a gimbal and landing gear to my F450, and noticed that when, in GPS mode, flying straight forward and then stopping, the copter would make a small circle to the left as it comes to a stop. I had not tried recalibrating.

Which brings up a question: how do you identify exactly the 3-axis COG? for X and Y, I suppose you can try holding the top plate on each side and seeing where it balances. But for Z?
 

T

Tahoe Ed

Active Member
I hang mine from a door frame and draw a line straight down to identify where to set the z component. The x & Y are pretty much at the center of the craft.
 

A

AirPix

Member
What I propose to do with mine is to have a small bracket attached to the side of the center frames with a light rod parallel to the z-axis. Orient the 'copter sideways (ie, booms vertical) and hang it from the rod. The point along the rod where the booms are absolutely vertical ("plumb") is the balance point of the z-axis and is precisely that distance below the center plate. Does that make sense? if not, I'll work up a drawing.

X and Y is easy-- hang from the geometric center and balance things til the booms are level.

Balance is critical in any aircraft. In a multirotor, if things are not balanced, the Flight Controller can make the 'copter fly straight and hover. Likewise, a fixed wing with warped wings and misaligned tail planes can be made to fly straight by trimming the control surfaces. But neither case is optimal, and both aircraft will do better if they "fly straight" with the controls neutral.

--Bill
 
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A

AirPix

Member
Here is a diagram showing the idea I was discussing for a way to measure the "z" value when balancing a multirotor. It shows a "bare" quadcopter with the z-balance rod installed and hanging on a string. The actual "z" value should be determined with the props, battery, camera and camera mount attached, and the 'copter in perfect balance in x & y ("flight ready").

View attachment 16478

Add this measured "z" value to the distance between the DJI GPS puck and the top plate to get the total Z value for the Assistant config data.

--Bill
 

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S

smackenzie

Member
AirPix said:
The point along the rod where the booms are absolutely vertical ("plumb") is the balance point of the z-axis and is precisely that distance below the center plate. Does that make sense? if not, I'll work up a drawing.

X and Y is easy-- hang from the geometric center and balance things til the booms are level.

--Bill
Click to expand...

Yep, makes total sense - thanks!
 

D

Dyver76

Member
Isn't the x, y and z measurements just the offset distance of the GPS puck from the center of the flight controller? And the flight controller should be a cog? If so then you shouldn't have to keep changing there values unless you change either of the locations. Right?
 

T

Tahoe Ed

Active Member
The assumptions above are not correct. Set up your MR in ready to fly condition. Hang it from a door frame from a motor and draw a line straight down. That will tell you where the Z axis intersects the X and Y axis. Then you can measure to the base of the GPS puck. My F550 is bottom heavy, especially when I put 2x4Sx4000 lipos on. That moves the COG. It does make a difference in flight performance. I have been doing this since starting with the WKM before the Naza came into existence and have never had an issue.
 

D

Dyver76

Member
I missed under stood that section. I thought the z value was the distance from the top of the puck to the bottom plate and the x and y was the offset from cog. I didn't think z would ever change unless you changed the height. I might need to see a video on this to get it.
 

B

buckers

Member
From the Naza Lite manual........................

"Install all payloads that will be used during the flight, including batteries, camera mount and camera. Balance the
multi-rotor as you would normally, with the center of gravity (C.G.) directly on the center plate. Fill in the distance
between body center of GPS and the C.G. of multi-rotor in X, Y & Z axles as showed in the figure."


On a TBS, I'm not sure how to interpret the "center plate". There are markings on the lower plate (which I believe is "centre of thrust" - not gravity), but nothing else that I've seen. It's also ambiguous as to what to do if the FC is NOT on the COG, (for whatever reason).
 





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