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Old Feb 01, 2013, 12:41 PM
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First FPV! with Naza, and some gain questions.

Frame: HT-FPV
Motors: MT2216-12 800KV
Props: Graupner 9x5 (balanced, blade and hub)
FC: Naza / GPS

Starting Gains I have been flying:

Basic: 140,140,130,130
Atti: 140,140


SO.. I have been flying first via LOS, and the above settings seem to work well. From the ground it looks smooth, and RTH works great. GPS locks well, and the wind has little to no effect on the quad. LOS flying has only been done in GPS and ATTI modes. The first time I tried manual mode, the quad flipped over, and broke a motor, and arm. I have since "disabled" manual mode in the radio via endpoint so there is no chance I will hit this by accident in the future. I enable Manual mode ONLY to calibrate GPS and then back off!

This week I finally did FPV for the first time! And.. it was more then just a little hovering around. I was 300+ meters all around me, and flying most of the time full stick positions to get the quad to "buzz around". The FPV flights are done in ATTI mode.

Issues / questions:

1. From the FPV view, the quad seem to fly okay, with the exception of a few turns (rudder, and banking) resulted in some violent shakes / wobble for about 2 sec. and then went away. Not all turns.. but a few of them.

2. Slow forward flight. Yeah, I can tell that the FC is "restricting" the quad in the air because it sometimes moves faster then other times in FFF? I assume wind makes a difference but I did not pay attention too much to that. The wind was light. (5 maybe 10mph.)

THEN.. I watched the video from the gopro.. and was noticing more issues:

1. The motors seem to hesitate when I first take off and am gaining altitude fast (on the way up) some small vibrations as well can be seen and heard.

2. Clearly can tell that there is hesitation / fighting with the FC for some of the forward flight / turns.


So now I assume the gains are a place to "tune" this? What I dont fully understand is the difference from "Basic" and "Atti" gains. I have tried to find documentation on this and to no avail.

For example, does the "basic" gains effect Atti mode at all? and does the "atti" gains ONLY effect atti mode and not GPS?

I would assume manual flight (although scared to death of it) would be the smoothest flying mode in terms of FFF and tight movement (clean banks, and tight turns).. But, perhaps I can "dumb down" atti mode to give better performance close to manual, but with some security?

OR Should I try re-programming my radio so that manual is used with TONS of DR / EXPO? and leave the gains high?

Please help!

Thanks!
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Old Feb 01, 2013, 06:13 PM
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Please.. Anyone? In running 4S too. (Forgot to mention that, if it makes any difference. )
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Old Feb 02, 2013, 04:19 AM
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I had similar issues as you with my Witespy quad and I coincidentally had the same gains as you. I've been playing with gains settings lately because I found that all the descriptions online didn't make alot of sense. At the moment, I've moved to 120 on all the basic gains, and 80 for the ATTI gains. Its alot more smooth now, almost like its sliding on ice. I'm still working on tuning to find the perfect spot, but if you have a dial switch on your transmitter and an extra channel on your reciever, you can connect either X1 or X2 port from the Naza to that channel and you can adjust the gains in the air to find the sweet spot on your own. I'm hoping to make a tutorial video sometime soon showing the effects of the gains during flight, but for now, I'd suggest taking all your gains down 10-15% and trying it again.

The best way I can explain it, the basic gains set how fast the craft will react to inputs from the sticks. Too high, and there are oscillations during flight. Too low, and the craft feels a little slow to react. The ATTI gains are where I really see a difference though. With the ATTI gains high, the craft really reacts quickly, and in wind, a bitt wobbly. With the ATTI gains really low, the craft stabilizes slower, and slides likes its on ice.
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Old Feb 02, 2013, 05:31 AM
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Hi, what esc's are using?
Because you might want to look into flashing them.

By flashing them you load a new custom firmware written especially for multicopters (look for simonk). The result is a more stable flight.

Have a look at this:

http://wiki.openpilot.org/plugins/se.../view/24150561

But there is a lot more info to find if you look around.
I did my esc's 2 weeks a go. (20a mystery blue series).
A real fulfilling job!
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Old Feb 02, 2013, 09:14 AM
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Dartmouth01 is spot on. On the Naza the basic gains determine the overall stability of the multi and how quickly it follows stick inputs from the TX, too high and it will vary from twitchy to continuous oscillations, too low and its barely controllable because it takes too long to respond to inputs. Atti gains determine how much influence the autoleveling has beyond the stability of the basic gain settings and they only have an effect in Atti and GPS modes.

With a Naza it is very difficult to tune it to one set of parameters that will work perfectly in all conditions and modes. I currently have 3 Naza on FPV quads and all of them have at least the Atti pitch and roll gains adjustable from my TX and on the ones that have enough available RX channels I also have the basic pitch and roll TX adjustable, that way I can "tune" the settings in flight for the best overall response. Rarely can you find exactly the right settings for a perfectly smooth flight unless there is little to no wind, usually its a compromise between smoothness and response.

Since I do the majority of my FPV flight in Atti mode I get the basic gains to a point where the quad has good stability in manual mode but not so high that it becomes stiff and twitchy or is constantly overcorrecting in Atti. If I want to fly in manual mode I usually just turn the basic gains up so it flys well and forget about using Atti until I reset the basic gains back to a lower range, one of the reasons why it's nice to be able to adjust them from the TX. To fly smoothly in Atti I have the Atti pitch and roll gains set for a range that varies from around 50% up to a maximum of 80 to 90% depending on the frame and motors with the mid point of the adjustment around 65 to 75% which I've found the "sweet spot" to be for flying in Atti. That range give enough stability to not have to be constantly correcting but not so much that the multi is stiff and overly fast to go back to perfectly level, in calmer air I can turn them up to the higher numbers and in wind I lower it slightly below midpoint so the responses are more fluid.

If there are gusting winds it's never going to be a perfectly smooth flight regardless of how you set the gains but if you can make adjustments while in flight you can usually get to a point where it flys well and doesn't get pushed around too much by the wind. This video is my TBS Discovery on a day where the wind increased in strength from almost nothing to gusting in the 12 to 15 mph range by time I was ready to pack up. At the very end of the vid a big gust of wind knocked the tripod with video RX over unplugging the goggles with the result being what you see at the end. Just before the end you can see I have to make larger corrections to stay on course because of the wind but the quad isn't out of control or twitching while in FF...

Januaryfpv (8 min 29 sec)
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Old Feb 02, 2013, 10:50 PM
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Thanks everyone. I now have a bit better understanding on the gains, and good to know I am on track.

@ RTRyder - Are you flying 5.8GHz? That was a great video and I really enjoyed it. Totally sucked at the end with the snow ditch.. but, at least it was not a mechanical failure.. somehow I would feel better knowing it was the wind, and etc.. That was some great range when you were flying behind you through the trees.. about how far was that?

@ Rutger I am using 20A whitspy (Rapid Fire) ESC's and they are in fact flashed with SimonK.

@ Dartmouth01, Thanks so much.. funny that you started with the same inital gains. I may end up just like you too.. LOL. The sliding on ICE feeling sounds about what I am looking for. I like to almost fly it like a plane, so perhaps this will give me a bit more control.

Well, I finally got a CCD camera for FPV view so tomorrow I will be testing that out.. and I made a new mount for the gopro to rid all vibration with gel. Then I had to re "CG" (balance) the machine ready to fly. In fact, I had to add in $1.50 in quarters in the front to get it to balance close to perfect. Unfortunately sliding the main pack forward would not work as it was maxed out in the frame slot. Perhaps some of my issues were a result of poor CG in start with.. and the whole time in ATTI or GPS the FC is compensating for that. Although I never noticed any motor warmer then the others with thermal temp scan after flights.. but who knows. At least now I know it is balanced.

I will report back!

Thanks again so much!
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Old Feb 03, 2013, 09:00 AM
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The other thing I was wondering.. is the difference (on paper, as well as in the air) from running 8" props vs. 9". What I mean by "on paper" is what are the tech. performance difference from each?

For example, I would guess that 9" prop will create more lift, and therefore be more efficient to the power setup and motors. However, at the cost of being more respectable to wind, and possible harder to control in tight turns / nazza fights more?

vs

8" props I would guess, a bit more nimble on the control.. and better in the wind.. however, will cost more in flight time as more power draw is needed to create the same lift? (higher RPM)

Thoughts?
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Old Feb 03, 2013, 02:46 PM
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Actually, I find the larger the prop, the better the craft handles. Also, generally (I think to a point), you get more battery life because the motor isn't working as hard. But generally propping down will reduce jello in the camera, unless you have things perfectly balanced already. Yes, wind can effect things more with larger props though.
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Old Feb 03, 2013, 03:46 PM
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Thanks Dartmouth! Well then, perhaps sticking with what I have is the happy medium.

So, I dropped my basic gains all to 120.. LOL and I am running 100% on the Atti. So, far pretty good. I still hear a good amount of hesitation in the fast climbs on take off from the motors.. so I think there is still something there fighting.

One thing I see that has happened.. is the GPS hold now seems to want to wander in a circle. It also seems to pull to the right as soon as it is activated. Then gently hovers around in a circle. Still seems to be functional.. but interesting huh?

I have been able to pin down one thing that I experience that def. is a little scary. This may or may not be wind related.. as all my flights seem to have some type of damn wind no matter how early I wake up.. LOL. Okay, so I will be high up (200+ft) and flying forward with good authority. Then, I will want to turn / bank and turn tight around the field. So, I give some YAW and ROLL at the same time, at the same pace and I see that sometimes the YAW does not seem to want to pull the copter around.. I have to partly stop the ROLL, and then almost FULL YAW and then back to forward and then roll to get it close. I am looking for a smooth action on the turns.. but and willing to say it might be me. coming from helis, I am flying it like one..
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Old Feb 03, 2013, 04:09 PM
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+1 for putting gains on a knob. Lets you dial in exactly where you want it
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Old Feb 03, 2013, 05:42 PM
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Quote:
Originally Posted by Tharr62 View Post
2. Slow forward flight. Yeah, I can tell that the FC is "restricting" the quad in the air because it sometimes moves faster then other times in FFF? I assume wind makes a difference but I did not pay attention too much to that.
I noticed that aswell, and that's my only gripe with the Naza, in ATTI it's a bitt too restrictive about the max angle in FFF, always have the feeling that it should let us a good 10-15 more for better *woooosh!*... And for better braking after these *woooosh*.

About yaw, I think its not good to have the yaw gain too high (>120), because anyway yawing with the torque isn't going to do miracles, and having this particular gain too high is doing more harm than good IMHO, during hard banks. That's the feeling I get on my F450 with 9" graup. at least, and I also like to fly it like a plane
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Old Feb 04, 2013, 02:15 PM
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I finished a first pass at the Naza gains tutorial and flight effects video:
Naza Gains Settings How-To and Effects during flight (14 min 9 sec)


As for your GPS going in circles, are you getting full lock on the satellites? You can tell by looking at the blinking LED unit, it should be blinking only green in GPS mode. If its blinking red once in between, it means its partially locked (I think less than 5 satellites) and if it blinks 2 reds between greens or more, it means even less satellites locked. Not having full sat lock can have an effect on how locked in the unit will be. Also, did you calibrate the GPS (the dance), where you rotate the unit horizontally and vertically? I found that after doing this the first time, my GPS got ALOT better. Finally, there will be some drift in GPS mode, as the accuracy of full lock is still a range of a couple meters. But generally, my quad stays within a 2-3 foot radius even in drift.

As for the hesitation in the motors, I would check all your settings: radio, naza assistant, as well as if any of your ESCs are not tuned with each other. I dont notice any hesitation on lift off with mine, and I have pretty small motors carrying a pretty decent payload.
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