Replies to This Discussion

Permalink Reply by Marc Puig Pasarrius on June 22, 2012 at 7:33am

I also have purchased a DJI NAZA + GPS, after two weeks waiting for it I get a faulty GPS :( I'm having a lot of trouble with APM: compass, RTL and Loiter. I'll keep my APM for my planes.

• ▶ Reply

Permalink Reply by Bruce Jones on June 22, 2012 at 12:28pm

I too have not been able to get my new Naza GPS to work.  No matter what I do, I get "COMPASS-ERR."  Being a closed architecture, it's really hard to have any clue what's going on.  It's also not clear if there's any warranty and how you make warranty claims.

• ▶ Reply

Permalink Reply by Marc Puig Pasarrius on June 22, 2012 at 1:42pm

Today I've sent it back to the store. I didn't get any error, simply it was like the gps/compas was completely dead. I recorded this video.

• ▶ Reply

DeveloperPermalink Reply by R_Lefebvre on June 20, 2012 at 8:14am

Glenn, that doesn't look like the compass is running away, it seems to be holding steady.  It's the actual yaw solution that's going nuts.  What exactly were you doing with the tri when this was going on?

• ▶ Reply

DeveloperPermalink Reply by Randy on June 20, 2012 at 10:00am

I've had a look at Glenn's logs and his problem is not the compass and it's not the yaw controller code.    The APM thinks that it's turning all the time.  It's much more likely a hardware issue with the z gyro as suggested above.

I'd guess that the z gyro's gyro drift is really high or perhaps the AHRS_YAW_P parameter has somehow become zero?  increasing this number to 0.4 (or higher) might temporarily resolve the issue although getting a new oilpan might be the best solution.

Could you turn on the RAW log type and reattached your dataflash logs?  the RAW type shows the raw imu values.  Alternatively some of the values that you're seeing in the MP's status screen for the gx, gy and gz values.

• ▶ Reply

DeveloperPermalink Reply by R_Lefebvre on June 20, 2012 at 10:57am

Yeah, that makes some sense.  It seems to be spinning at a constant rate.

This could be caused by damage to the board, or booting up/calibrating without the copter sitting stationary.  I've had this before with roll when I moved the heli while it was calibrating.

• ▶ Reply

Permalink Reply by Marc Puig Pasarrius on June 22, 2012 at 7:14am

This is related to faulty hardware (unsoldered pin connections of ic's), I have two dead APM that show signs like that. When I put my finger over gyros/accels values change: sometimes they get better and sometimes they get crazy. This is due a crash, a heavy g force scenario. I usually fix them reflowing the chips with a heat gun and a IR thermometer but it's only a temporal solution (maybe I don't reflow it properly).

• ▶ Reply

Wiki NinjaPermalink Reply by Gary McCray on June 20, 2012 at 9:51am

Hi Glenn,

I have looked over your pics and the various responses to this problem.

You have a fairly heavy Tricopter, wood frame and big battery.

This means high current motor surges in flight.

I saw one responder felt it was not magnetometer related, but if it is, a good fix is to put a metalic shield between the mag and ANY high power wiring.

I put some aluminum tape on the intermediate board between my power distribution board and the APM2 and it solved problems that I was having both with the GPS and the compass.

You seem to have yours sitting on a clear plastic board, I would suggest putting a thin aluminum or copper sheet or some aluminum tape under it, at least its easy to try.

• ▶ Reply

ModeratorPermalink Reply by Dean Wynton on June 20, 2012 at 11:09am

Hi Gary,

In theory using aluminium tape would not stop any magnetic interference? and not much static interference either? if it was grounded? it would stop alot of the static interference but not the magnetic?

I am not saying it didnt help? but scientifically it doesn`t make sense.. At least not to me anyway? :)

• ▶ Reply

Permalink Reply by Gustav Kuhn on June 20, 2012 at 11:34am

Dean,

Kind of with you here.

To shield something, you need the shield to shunt the interfering signal to a common grounding point.

Aluminium tape will work to a point, but it needs to be connected to a point as close to the ground of the system. Probably be the power board on a standard quad. With a short wire.

Much better would be the uMetal shields that used to be wound around motors in tape decks.

You know, the stuff before iPads ?

Still needs to be grounded though.....

Fortunately, with the high frequency stuff we use today, Physical separation "might" just be adequate.

I had a problem where my gps couldn't lock, until I moved it about 3 inches away from a 2.4GHz Rx !

My RF resume' ?

I'm in charge of 2x 25 KW MW tx's, 567 KHz, 729 KHZ, and a bunch of 10 KW TV transmitters, VHF and UHF.

• ▶ Reply

DeveloperPermalink Reply by R_Lefebvre on June 20, 2012 at 11:50am

Aluminum can work to block magnetic fields if they are rapidly changing/rotating fields.  Eddy currents get set up in the aluminum which, by happy chance, counter those of the field.

However, it cannot block stationary fields, such as from a permanent magnet or iron, near the Mag.

And unfortunately, it is those stationary fields which have the greater effect on the Mag calibration. MuMetal is the answer here.  In short, MuMetal creates a "short circuit" for the magnetic field lines, re-routing them through itself so that they don't affect the mag.

• ▶ Reply

Wiki NinjaPermalink Reply by Gary McCray on June 20, 2012 at 5:29pm

Aluminum between 2 magnets is used as a damper in old beam balances by the principal you describe above. 

MuMetal is the most magic and hard to get magnetic shielding material available.

And short of physical separation the only one that can really effectively block a static magnetic field.

However, most of the described problems have related to the ESCs or Power distribution wiring which is anything but static and who's interference is heavily attenuated by the aluminum.

My system went from unreliable operation of both the GPS and Magnetometer to reliable with just a little aluminum tape between the Power distribution board and the APM.

Got a good source for MuMetal. 

• ▶ Reply

• ‹ Previous
• 1
• …
• 24
• 25
• 26
• 27
• 28
• …
• 68
• Next ›
• Page