Electrohub build [Naze32 and FT's power kit] wobbles on take off.

[Chioxin]

Heya, so I've been flying prebuilts for a while and they were a lot of fun. So I thought I'd take a cheap nose dive into building my own. I purchased the Electrohub, the naze32 acro board, and the power pack that was suggested for it. Figured if I wanted to delve deeper, I'd do that on my next quad. I did buy the angle brackets and I kind of suspect that those might be my problem currently. ANyway.

Assembly was fairly easy, some soddering was a bit scary, but all in all it went together well from what I can see. I set it up with my laptop, made sure the receiver works right [and it does,] calibrated the ESC's, made sure all the settings were correct according to FT's video on the Naze 32 board. I take it out to test fly and in manual mode hovering, the entire thing wobbles. Left and Right is appears, not really forwards and backwards. Now, I can fly it around just a little bit this way, and keep it under control. This is fine. If I swap into Horizon or Angle mode, the thing wobbles hard until it eventually flips over. Thankfully i've only done that once, and at low altitude to avoid any real damage.

So, more specifics?

I built it as a quad, and I did set it up in deadcat style. Because of this, I have moved the Naze32 back on the quad a bit to account for center of gravity [maybe that's the issue? FT's videos said to do that.]

I also bought the angle arm brackets, because I really wanted a stable and possible video copter later once I eventually build my 250 racer. Now, there weren't any great examples of how to actually use the brackets, I did make use of it to the best of my abilities but I couldn't really figure out how to make it square. [I do have 4 other sticks, so I'm seriously considering tossing the angle brackets and just using straight arms. Maybe that's my problem? It's kinda what I'm guessing right now.]

I didn't adjust anything in PID tab, I left it alone. However I tried switching between a few of the options there? [MultiWii old, new, and 2.3?] and honestly I didn't see any of the settings changed at all between those. So I wasn't sure what that meant.

I found it really hard to get a good place to put a battery under this thing. I'm considering building my own kinda strap for that. The battery literally only hangs on the back two holes of the electro hub. I can't fit another strap on there to center it more.

=====

So right, any help or suggestions would be nice! I do feel kind of stuck at this point. Thanks =D

 

[makattack]

It definitely sounds like a pid tuning issue. I wouldn't use the default pids for any controller other that pidc0 - the default controller. For some of the other ones, the default proportional gain is way to high, I believe. Any oscillation is due to that. It could also be vibration from unbalanced props/motors.

Good to hear you've got your first build some! Now it's just a matter of tuning. Do not go into the level modes until you have it tuned in acro!

 

[Chioxin]

Really? The P is probably to high? I was wondering about that because when I took a peek in that tab a lot of the P's were set between 4 and 10, while a lot of the I's were between .4 and .9 [I think, can't look at it right now.] I didn't touch anything because FT says "Don't change anything, just run it as is at first!" Or so I thought. I'm going to have to watch those videos again real quick just to see. It's not a fast vibration though, more just a wobble. Can I put all the PID stuff down to 0 and just work my way up from there? I just don't know what a good base line is to start at and then move up from. I wish I had a TX with a dial so I could easily adjust them during flight and find the right spot with ease. Sadly when I started this whole thing, I got just a decent computerized 6 channel controller. [Spektrum DX6]

Guess that's what I'll be doing tomorrow, is playing with those settings a little bit.

 

[makattack]

Yeah, I think the ft build video assumes pid controller 0.but it sounded like you changed yours. What is it on now? The right value depends on the props, motor, esc, frame, Build, etc. I would not go to all zeros. I get a baseline by tuning with the multi rotor in my hands, and carefully moving it on the roll and pitch axis. If you do so, do it very carefully. Best is to do it in a tethered harness setup. Wear eye protection. Maybe start at 2 for p and lower the i,d to zero?

 

[Chioxin]

I'll give that a try. I'll update tomorrow with what I find out.

When people talk about PID, it's not literally just 3 numbers though is it? There's P for YAW, P for PITCH, P for ROLL [and I think a number of other things?] And then there's an I for each of those, and a D for each of those. Right? So I'm adjusting different P's, I's, and D's basically.

 

[makattack]

Yes, there are also rates, and level gains, but for now, when just dealing with PID's on roll, pitch, yaw, I based all my experience on the original multiWii software (running on a Flip 1.5) and this guide:

http://www.multiwii.com/wiki/?title=PID

Since baseflight/cleanflight are forks of MultiWii (with cleanflight being a fork of baseflight), you can essentially use the same guide. I believe the PID controller 0 of cleanflight is basically the same as baseflight, which is based of MW 2.2 -- but don't quote me on this!

 

[Chioxin]

Great! Thanks so much =D Experiments shall continue! I'll remember to take some screenshots too so I can at least post what I've been doing.

 

[Chioxin]

Alright so I'm at the shop now working on my multirotor. I have it plugged in. I can only really send links out of my drop box =( Which means for future viewers, these will eventually go away =( Sorry =(

This is what it has when it's out of the box. The "BASE" setup

Base Settings - Controller 0

Now when I flip the "PID Controller" to #1, there's no change in any of the variables.

PID Controller - 1

But anyway, that should show you what the defaults were. I'm guessing they look a little high? I'm going to adjust them now. I'm only going to change Pitch, Roll, and Yaw though?

 

[Chioxin]

Alright, even with these following test settings:

PID Settings -Begin tuning

I am still having issues. The craft lifts off, but it constantly tries to tilt forward, and it also yaws to the left. I'm seriously considering rebuilding my booms to see if flat booms might fix the problem instead of these angled arms I have going right now, as I seriously think I did the angled arms wrong.

 

[Chioxin]

Replaced angled arms with just straight arms, and it seems to work a lot better now. So I'm guessing my angled arms were really messed up, enough so to cause the problems I was experiencing. Now, we're back to tuning.

A new issue that has come up though is that when I flick the ARM switch, the blades won't always turn on, and some times I have to give it a little throttle to get them to turn on. Not sure what problem that is =/ When I look in the "MODES" tab I can switch the arm switch and will see it move to "ARMED" but that row will not turn green. So this seems really weird to me, as it recognizes the switch is flipped but it doesn't act on it?

 

[makattack]

Glad to hear you have solved a few of the problems. It sounds like your latest problem is that your MIN_THROTTLE isn't set properly. I recommend setting it with the props off, plugged into the computer, and powered by a battery. You want to go to the motor screen, and check off the box for manual/GUI control of the motors. Then, you want to raise the master slider until the motors just start turning. Make note of the PWM values, then go into I think it was the config screen/tab, and enter that into the minimum throttle box.

 

[Chioxin]

Which I'd done originally. It was 1200 for me, I've now bumped it up to 1225. Having concerns that one motor is not awesome... under powered, or something.

 

[Chioxin]

Well here's a video of what it's doing:

Flite Test - Electrohub

Using these settings:

PID - DialingIn-1

Is there anything that explains ALL the variables? Which ones I should be playing with? As of the moment I'm only really touching Pitch, Yaw, and Roll, but I'm also playing with "Level" just to see if that's what's causing my jitters.

 

[makattack]

http://www.multiwii.com/wiki/?title=PID

Is a pretty good start to understanding those variables.

 

[Chioxin]

I read that, and for me it still possesses the same problems of what I'm looking at here. I understand what they're saying about P, I, and D, what I want to know are what....

Roll - I know this
Pitch - I know this
Yaw - I know this
Alt - Altitude hold? Do I care about this?
Vel - Velocity? Motor speed change? What is this?
Pos - No clue
PosR - No clue
NavR - No clue
Level - Auto leveling features? How much it listens to it's gyro?
Mag - Pretty sure the Acro doesn't have this.

Do I adjust all of these? Do I just touch Roll, Pitch, and Yaw... and then set the rest to 0? [Pretty sure I need Level, been playing with that lately. Seems to help? Maybe it's a placebo though.] When I adjust P, do I adjust P for all of them equally? Or just the one at a time?

 

[Chioxin]

Ok, more progress incase anyone has similar issues and looks up this thread.

Edit: And now that I read back, Mak you said don't go with all 0's Heh. Sorry about that, I think I was getting information all jumbled up with all the posts I was reading. If I had done that first thing, today would have started better! So, thank you so much! =D And sorry for missing that VITAL piece of information.

I think I'm finally getting things moving towards the better. I don't know why everyone else I've read says "Up P, leave I and D at 0." But this is not true. With the Naze32 at least, and with my experience, you need some I and D in there to start with before you start increasing P. I suggest starting around I = 0.010, and D = 1. Things are still not really "locked in" but, they are A LOT better now than they use to be, and from here I can experiment more and more until I get it locked in.

The end, for now.

 

[JohnRambozo]

I know this is an old(ish) thread but for those that found their way here, I'd like to direct you to Oscar Liang's great tutorial on using Cleanflight with the Naze32.

Which also includes a description of the different PID Controllers available in Cleanflight. When changing the Controllers in addition to the values, it also changes the way the PID values are interpreted by the controller and those changes won't become apparent until you are flying.

I'm still very noobish in the quad world but these tutorials have been immensely helpful.

One more thing. Regarding the issue with arming and throttle response (min, max throttle). I read there is a safety measure that prevents arming above a certain throttle range. In order to arm properly and still get proper throttle response, you may (as I did) actually have to trim your throttle down using the controller trim switches (while looking at the Receiver tab in Cleanflight) so you have a throttle min starting at around 1060, with the throttle fully lowered at just around 1000.

WARNING - I found if you go too low with the throttle trim, it will actually have a kind of out of range effect where it either becomes unresponsive or jumps to 1500. Don't go much below 1000 with your trim settings.

I am using a Spektrum DX5e, Naze32 and Cleanflight.