Servers by jDrones

MicroArduCopter, 3" props, Omnibus Nano, Success!

(S) #203

It does


(Paul Atkin) #204

hmm, it is interesting, i never tried that. what would you set those to, and why?

i would guess ins_notch_freq=350, what else?

then, after it is setup - would i expect to see a different readout in the vibration 3.3. graph, or it should be visible in the same FFT graph?

(S) #205

ATT=15? (This is the amount the filter attenuates… You might need 20 or 25… I’m not exactly sure how to interpret the logs)
BW=100? (This is the bandwidth, but I’m not sure of the details… It looks like you need just over 100hz to null out that spike… But the other couple examples of people using notch filters I’ve seen are only using around 10hz… But their noise spike was much thinner, too)
Enable=1 (I think 1 generally means to enable)

But, I have no experience… Maybe Dave or someone who has actually tried it will post at some point.

I would imagine if you have the filter enabled, then the vibe reading and the FFT will show you the post-filtered results, so you should see a change in the vibe and fft graphs. But again, I am not positive as I’ve never tried it…
I need flash logging on this omnibus nano!!

(Paul Atkin) #206

thx - i am trying it now… as of omnibus nano - i do not like it, it is just too limited. i hope may be matek will make new better controller soon, will see.
from other perspective - a 20mm mount, but, still, too limited.

interesting, the ins_notch_freq in MP has a top limit of 200. i used value of 350, will try to fly it now and look at log.
soo, a result is rather discouraging. with a center freq set to 350, notch_bw to 50hz, notch_att to 15 db it flips over at takeoff and refuses to fly. turning it off makes it work fine. i will try to reduce those params but i do not have a god feeling about it. it is not an effect a notch filter would be expected to produce…

and i just grepped whole arducopter code base for ’ INS_NOTCH’ word and it found nothing. will try asking at dev channel - i would like to see where is it coded.

(Dave) #207

Sorry Paul I played around with it just enough to be dangerous and I wasn’t really chasing a problem just experimenting. I wonder whether a frequency that high can really be accomplished with the loop rates running in Arducopter. Asking in the DEV thread is a good idea, I’ll be interested in the feddback you get. Here is some additional info on Batch Sampling.

(Paul Atkin) #208

yeah, i will see what will transpire. all i can tell so far - any setting i tried to use has produced an immediate flip-over upon an attempt to liftoff. so i keep it disabled for now.

only good news so far is that tridge may get to the uart driver some time soon, it would be nice to get inversion done i the driver code.

(Hugues) #209

What is today’s lightest (and smallest) FC combo (stack) that exist on the market and is Ardupilot (ChibiOs) compatible ?
Anyone knows ?

(S) #210

as far as I know (Unless someone has very recently added another 20x20 FC to the list) the smallest FC is still the omnibus nano.
ESC will vary, depending on what you need. Ori32 is small, but heavy. Something like a racerstar (or other random esc) that’s only 10-12A or so will be lighter.

I don’t know about complete pre soldered stacks, but that’s really not important… ESC’s are just 4 or 6 or so wires to connect.

(Dave) #211

What’s in your “stack” ? The FC this thread is about, Omnibus F4 nano V6, is 5 grams and it includes OSD, battery power in and a couple of BEC’s for external devices. Paired with a 20x20mm 4in1 (I use an Ori32) and it’s very light.

What wicked1 said about the Ori32 is right. Some of the additional weight comes from 4 large current shunt resistors!

(Hugues) #212

I’d like a “complete” lightest stack including FC, 4 in 1 ESCs, PDB. Also it must have current and voltage measurements (hall effect would be perfect but shunt resistor will do)

(S) #213

Also about weight…
When building a small copter like this where you’re at a huge disadvantage with your prop efficiency(due to small prop size), I think it’s a good idea to always keep the weight in mind… For every component. Obviously the big ones like VTX, and receiver. But even the diameter of wire you use, the amount of solder you use. Your antenna choices. If something has connectors, it might be best to cut them off and directly solder. Battery strap choice. Whether or not to secure things w/ extra glue. Prop weight. Everything!
When looking at the weight of things, a gram or less might not seem like much, but when you consider it for every component and every material choice, it all adds up.

(Hugues) #214

yes. My first step in that direction is designing a 3" frame that is as light as the lightest I have seen on forums : about 12gr.

(S) #215

If you want to solder your own, I can offer advice for every component.
If you want a pre-made stack, you aren’t going to find much… Like we’ve said, the only 20x20 board supported by arducopter is the omnibus nano. There aren’t many stack choices out there w/ that particular board.
Then you jump up to the larger size FC’s, and a lot more weight.

Edited to say, the FlexRC 3" frame I’m using is about 15 grams. I’m mostly happy with it… The props are in the shot a bit more than I’d like, but it’s a compromise I’ve got to accept for now.

(Hugues) #216

I like the Omnibus F7 V2 for its vibraiton isolated IMU but it is much larger and heavier relatively to the nano.

(Paul Atkin) #217

there may be some very small light stacks in 20mm for arducopter on f4 chips - the issue is what it is you want to put on uarts. as soon as you start using a lot of additional devices - any f4 chips renders out as you need gps, lidar, RCin, telemetry out - a f4 chip based FC would usually have only 2 free uarts for you to use after you connect your radio. there are some exceptions like f4 omni FC - where radio can go to some other pin instead of occupying an UART.
that is why i built all my models on kakute f7 as it has a lot of uarts. matek now finally made new controller as well based on 765 chip that probably will be a new best choice, if it will work well and get hwdef file.

(Hugues) #218

What is the weight of your kakute F7 stack (including 4-in-1 ESCs if any ?) ?

(Paul Atkin) #219

it is not very light.
whole build with no battery is about to 200g. 1500mah 4S lipo is 250g or so, so, it pushes those motors a bit much.

stack i used was this one:

it is not only stack that is heavy, it is motors. plus lidar, gps, esc8266 board, r-xsr, foxeer camera - it all adds up.
motors are brotherhobby T1 1407 3600kv. i could have used bigger ones, i think, it would be better. something with bigger stators that can still mount in the 1407 format.

(Dave) #220

Hi Paul-Are you happy with that Matek GPS module? I’m planning on building a plane with a F405 Wing and that looks like a good option.

(Paul Atkin) #221

Yes, i like it. It works well.

(Paul Atkin) #222

a bit annoying thing happend - owl frame oscillated and propelled up in alt hold, i automatically killed motors and let it drop down, as i usually do - as armattan frames are pretty much indestructible.
not so much about owl frame… $80 out of the window, its 2mm carbon came apart in 3 places on both plates. pretty whimsy quality carbon, i must say… i wish they made it from 4mm one, as i do not care much about weight - it would be better to have it sturdier.

so, ordered now their new gecko from armattan, will see how will that work out. and ordered a omni v6 nano board, so, will probably get to its guts soon. do we still have an issue with logging not working on it? is there an internal storage on it for logs, at least, or nothing at all?