Yaw and altitude hold with Naza/GPS

[Bison52]

I'm still having a little bit of an issue with yaw on my GPS. Holds altitude in a hover but put in the least bit of yaw and it seems to lose position lock, just wander off.

The other thing I haven't ironed out. In atti mode, I can set an altitude and fly quite aggressively and it will hold that altitude well with no throttle input. But in GPS mode, any back or forward flying causes it to lose altitude.

I have been careful about compass calibration and have the mounting/COG info input correctly so I'm kind of stumped.

Anybody else experienced this?

 

[monster900]

I have same problem with gps and yaw, i try only in strong wind for the moment but it's same your problem with lose position lock. I found also a really big power consuption in gps mode.

 

[Bison52]

My power consumption also goes up in GPS mode. Have no idea why.

 

[sinaregg]

Yeah I'm experiencing difficulties with gps also. Hex rose in air and altitude hold was unstable. Again change in altitude. I haven't checked to see how many sats were acquired but gps mode light was green.
Other time at low altitude (1 meter) it held just fine.
Other time hex was unstable

 

[DJIFlyer]

Not sure if this is off topic but it does apply to losing altitude: Why is it that neither my Naza with GPS nor the WKM (in GPS or ATTI modes) can hold altitude while on the move laterally? If the throttle is centered and I am hovering I find that I will either gain or lose altitude immediately upon entering any of the other three flight controls (some more than others). Why do these units not attempt to hold altitude by automatically increasing or decreasing throttle as needed to hold that altitude? I find that raising or lowering vertical gain has no effect upon this issue yet DJI suggests in their documentation that if the units loose altitude in horizontal flight it may be due to vertical gain settings. I have always assumed that my quad is overloaded and that this is the reason why it is happening but I have recently heard that this is just how it goes and not to expect the quad to hold its altitude while in flight across the ground. Bison52: You stated; "In ATTI mode, I can set an altitude and fly quite aggressively and it will hold that altitude well with no throttle input". I have never been that fortunate. Does anyone have any input on this?

 

[Bison52]

I strongly suspect this is simply a matter of gains. If the basic gain for throttle is set correctly, the craft should be able to maintain a fixed altitude while engaging in horizontal flight. If it loses altitude while maneuvering, throttle gains should be increased. Gains are tough. I mess with mine all the time trying to find the sweet spot.

 

[DJIFlyer]

I strongly suspect this is simply a matter of gains. If the basic gain for throttle is set correctly, the craft should be able to maintain a fixed altitude while engaging in horizontal flight. If it loses altitude while maneuvering, throttle gains should be increased. Gains are tough. I mess with mine all the time trying to find the sweet spot.

I have tried everything with the gains including setting them up in both groups and individually via X1 and X2 to adjust while flying. At this point I suspect that the overall weight of the quad is a little too high and that this is effecting its ability to hold altitude. My motors are rather small for the size of this quad so I may just have to live with it until I can build something more powerful. The odd thing is that there is lots of instant power for vertical lift when I touch the throttle (it will still shoot straight up like a rocket) therefore it seems that there should be no problem holding altitude when in flight, if that's what its designed to do. The problem is that I do not know whether 'altitude hold' is part of the plan for these units while in flight.

 

[kloner]

when you guys calibrate your naza to the radio, are you putting the throttle back on 50% perfectly before hitting finish? if not, try it, should have some monitor or way to see it in the radios display

 

[DJIFlyer]

when you guys calibrate your naza to the radio, are you putting the throttle back on 50% perfectly before hitting finish? if not, try it, should have some monitor or way to see it in the radios display

I am going to try this right now (I'm desperate). Have you tired this and does it make a difference as far as you know?

 

[DJIFlyer]

when you guys calibrate your naza to the radio, are you putting the throttle back on 50% perfectly before hitting finish? if not, try it, should have some monitor or way to see it in the radios display

Hello again. I was just re-reading your comment. Were you referring to calibration in the Naza assistant? If so wouldn't the green color indication in assistant be enough to know that the throttle is now centered? I figured that is what you mean but then when you mentioned possibly monitoring it on the radio display I was not sure.

 

[kloner]

the only place to calibrate naza is in assistant.

thats what makes mid stick hold an altitude. otherwise naza never learns what mid stick is

you also want the alttitude gain around 120-140.

Yes i have, just got one, just did what i said and it fell off lock when it yawed, but it held altitude perfectly, always does. i use throttle hold set to 50% so can bump the throttle during flight doing the rudder without making it go up and down. it always holds it a few feet up and down

 

[DJIFlyer]

the only place to calibrate naza is in assistant.

thats what makes mid stick hold an altitude. otherwise naza never learns what mid stick is

you also want the alttitude gain around 120-140.

Yes i have, just got one, just did what i said and it fell off lock when it yawed, but it held altitude perfectly, always does. i use throttle hold set to 50% so can bump the throttle during flight doing the rudder without making it go up and down. it always holds it a few feet up and down

Thanks. This sounds promising! I'm waiting for the afternoon winds to die down and then I'll give it a try. So, you feel that this is the reason why my altitude is dropping when I move laterally across the ground... because Naza never got the right command to hold altitude in the assistant with the 'green mid-stick setting' at 'finish'? Wow. They don't mention that anywhere in the manual, as far as I can recall, and I have been asking all over about this.

 

[kloner]

whats it weigh?

 

[DJIFlyer]

whats it weigh?

4.25 pounds including the lipo, Gopro and ready to go. Its on a 550 quad frame with 10 inch APC props.

 

[kloner]

3s? light for a hex

 

[DJIFlyer]

3s? light for a hex

Its a 550 quad with 3S 3800 mAh lipo. By the way. I was just able to go outside for a few minutes to test this out with the new setting. It seems to hold the altitude nicely in forward movement (elevator stick forward) but if I simply pull that same stick back to make it return it immediately loses altitude and I must add throttle to keep it at the altitude that it was at previously. I haven't had time to play with the vertical gain yet (just a little on the fly with X2) and I have not tried this with ATTI mode either. Hopefully in a little while.

 

[kloner]

this thing doesn't hold a perfect level, it does 3 feetish up and 3 feetish down. i wouldn't expect to set it a foot off the ground and not have to touch the stick, but if you go up 10 feet, it aint hitting. if you have a throttle hold switch, set it to 50% and hit the switch. i find myself dragging the throttle stick up and down flying normally, not a real good way to give the naza a test to hold altitude

You are on the edge of too heavy for your setup. you'd be better off with something like a 4s 3600 and 9" props

 

[DJIFlyer]

this thing doesn't hold a perfect level, it does 3 feetish up and 3 feetish down. i wouldn't expect to set it a foot off the ground and not have to touch the stick, but if you go up 10 feet, it aint hitting. if you have a throttle hold switch, set it to 50% and hit the switch. i find myself dragging the throttle stick up and down flying normally, not a real good way to give the naza a test to hold altitude

You are on the edge of too heavy for your setup. you'd be better off with something like a 4s 3600 and 9" props

I just came back in after a longer test and find that it holds altitude pretty well on the way out but wants to drop in altitude on the way back, as I was explaining. It seems that I don't understand that equation with motors, lipos, 3S vs 4s, etc. If the quad has all of this extra throttle whenever I need it why doesn't the FC send just a little bit of it to the motors to hold the altitude when it traveling across the ground. I don't see how this issue would change because of a 4s vs a 3s. I'm not question what you are saying, I just don't understand this stuff enough to make sense of the problem that I am having.

 

[kloner]

I wasn't saying the 3s and 10" is why it's not holding cause it sounds like your alot closer, i'd try up ing the gain to make it stick there now, 120-130 should make it happen. if it goes up and down fast, too high, if it falls like you explained, too low. the important thing is the naza knows half stick now. you can move that to 200, that'd be high....... put just that gain on the radio so you can switch it and see what really high and really low are like, should give you a better idea where the sweet spot is

my saying the 3s and 10" is at the limit is more to do with if you ever have anything but a perfect battery, theres a good chance of it not having enough rpm to do anything but go down, mine did that with 2215, 10" and 3s and right around 2100 grams, your at 2000.

 

[DJIFlyer]

I wasn't saying the 3s and 10" is why it's not holding cause it sounds like your alot closer, i'd try up ing the gain to make it stick there now, 120-130 should make it happen. if it goes up and down fast, too high, if it falls like you explained, too low. the important thing is the naza knows half stick now. you can move that to 200, that'd be high....... put just that gain on the radio so you can switch it and see what really high and really low are like, should give you a better idea where the sweet spot is

my saying the 3s and 10" is at the limit is more to do with if you ever have anything but a perfect battery, theres a good chance of it not having enough rpm to do anything but go down, mine did that with 2215, 10" and 3s and right around 2100 grams, your at 2000.

I will play around with the gains some more tomorrow. You stated: "theres a good chance of it not having enough rpm to do anything but go down...", but the fact is that I have tons of throttle to add anytime I want it. In fact I learned this evening that just adding a little bit will allow it to hold altitude as it returns so I do not believe that there is not enough RPMs available when they are right there if I just add a touch of throttle. It seems to be more of a short-coming of the FC which allows it to dip in in this way. I have heard many other complain about the same thing. I will say that your tip seems to have been a good one. It does appear to hold better than before so I am grateful for your time in helping me to gain a better understanding of these things. Thanks again!