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My First Build (Cheap250)
#31
Congrats Aaron! Looks like you've got the 3 P's down (patience, persistence, practice) Smile . Good on ya - keep it up!
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#32
So yesterday afternoon I whacked the GoPro back onto the nose and went out to fly.  It ended poorly.

Firstly I had real trouble on the ground getting a GPS lock so that I could Arm and fly.  Then instead of being all careful, enabling a basic Loiter or Alt Hold and just cruising about I decided to hammer into some forward flight.  

So what did I do wrong?
  • I didn't "balance" the Quad with the ~80g of GoPro sitting forward of the FC.  So the Quad was nose heavy.  Sans GoPro the flying weight is 536g so adding 15% more weight and not balancing does impose issues.  The Flight Control did stabilise the flight and balance it by cranking up the front motors more but thats hardly good.
  • I didn't account for wind.  So as the quad got 10-15m away from me into a more open area of the park it was susceptible to gusts of wind.  and I was flying about 2m off the deck and not compensating for height loss well enough.  
In short I rushed myself, jumped in too deep and didn't think.  I could have had a great 5-8 minutes flying around the park with the GoPro recording stuff and got a better feel for things.  Instead I nose planted at near full throttle flung the GoPro into the scenery and bruised my already tattered ego.

Try that again?
So I dropped the GoPro into my pocket - in the crash one of the little rubber dampers had gone missing from the mount - turned the quad over a few times and readied for take-off.

Without the GoPro on response was better and I immediately tried to teach myself some stuff about flying in the wind.  In stabilise mode I et it climb 10m or so up and flipped over to Alt-Hold.  Trying to counter the wind drift and so on was interesting although not impossible.  I could at least influence the direction and generally steer.  I did spend more time playing with Yaw on this flight.

Then I tried to descend for landing.  These have never been my strong suit.  

About 1m off the ground and I thought it was all find when it basically dropped a corner and plunged.  When I made it to the wreck I was missing a blade, but it was no-where to be found.  Im starting to think these Gemfan 5030's are absolute rubbish.  The black ones in particular just seem to self-destruct when scowled at.

Back home again
That brings us to this morning.  I figured I'd explore my GoPro mount - I don't have spare isolators and to be honest the camera must have sat a bit too far forward.

So I rejigged my build.
First I made a deck to mount the GoPro mount to directly without isolators.  The yellow material is PVC, cut down from a plastic body filler applicator, and has some flex.  In this position the GoPro can tilt back a little more and I can slip it another 5mm or so rearward if I want.  

The compass is on standoffs now off the rear of the FC position - previously it was directly above.  I think this will help the APMs internal compass a bit too.  I did try using the external compass but somehow cant manage to get the internal disabled! (Yes I cut up the track - probably need a magnifying glass when I next consider this).

   

It still looks neat, but it's far from pleasant to look at.  I've also bumped the battery rearward another 10mm which now puts the COG under the centre line of the FC when the GoPro is onboard.  The battery can be pushed forward easy enough to dead with flights sans GoPro.

   

I guess the proof will be another test flight this afternoon.  If the wind settles down.

Ohh I've put the Diatone 3-blades back on too. From playing with eCalc they should do a better job with my setup given the additional weight.
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#33
Well that ended badly. Was having all sorts of control problems flying with the new "layout" and 3-blade props.

Very little altitude control and the gps was all sorts of weird. In the end at about 30m altitude it started to completely fail to respond to direction in any reasonable manner and was drifting towards a nearby road. I basically had no choice but to zero throttle and let it drop dead stick. Ended up doing terminal damage on impact to the FC.

The GPS module seems to have gone offline in the middle of that flight and the GPS-FC lead was nowhere to be found. I suspect it got snagged into a prop and then the thing just went largely out of control Probably trying to do some failsafe move.

So further thoughts:
* maybe my 25c Zippy compact is right on its current limit (possible) so I'm getting brownouts under high-throttle positions - Have ordered (along with a cheap replacement APM3.1) a higher rated battery.
* the props just aren't suiting the setup I have.
* Its too heavy

When the replacement FC arrives I'm going to embark up a complete rebuild with the aim of cutting down weight and making everything neat once more.

Oh and why stick to the "old APM" stuff?
It's a combination of being 2 days postage away, low price (AUD55 at the moment from HK) and I've already taught myself a lot of the Mission Planner and Arducopter stuff. The micro form factor means I'll rebuild the frame and neaten up all my ESC motor wire lengths, get my LEDs mounted more neatly and generally try and get this assembled without the decks being fitted and the electronics more solidly mounted inside the core of the quad.
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#34
On the thought of weight reduction.

I think I will be at around 450g AUW post rebuild. The frame, battery strap, PDB, Rx, LEDs, GPS, and FC mount currently tip the scales at 470g and thats with a heap of extra wire on it. As my previous most stable config was 553g I should then be able to reintroduce the GoPro and still be stable
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#35
Well the time finally came to try the lighter build out.



I'm not sure thats a success. The Runaway at the end is the most annoying thing. Looking for help on the oscillations Smile
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#36
From gemfan 5030 to triblade 5045 it's a big step. I'm not familiar with your FC, but in general you'll have to lower the P-value in the PIDs a lot to prevent that "rodeo-ride".

And don't stay in the air with such wobbling - the constant acceleration/braking of motors puts big stress on the electronics, which in turn can lead to more failure: heat building up in escs and motors, battery voltage dropping and current rising, rx or fc shutting down due to low voltage...

If you have some gemfan 5030 left, i would recommend using them all up first. The advantage of brittle props is that the motors are less likely to take damage in crashes. Also if anything goes wrong, it happens with less power.
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#37
Yep. Am back on the 5030's and indeed was using them on that flight!

I've been doing some research and yes the P-values people are using at similar power and AUWs are about 1/4 what I had as the default. It was probably dumb luck that when I was about 130g heavier it was stable.
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#38
Does the fc/firmware offer more than 1 PID profile to be saved/recalled?

If so, you could set those up for different configurations: with cam (higher weight/higher PID), without cam, different props etc.
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#39
(24-Dec-2016, 12:16 PM)fftunes Wrote: Does the fc/firmware offer more than 1 PID profile to be saved/recalled?

If so, you could set those up for different configurations: with cam (higher weight/higher PID), without cam, different props etc.

Good point - it's Mission Planner so yes the configs can be saved and loaded.  I tweaked the setup yesterday afternoon so that I can now do the Autotune as well.  We will see how that goes Smile
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  • BigglesFPV
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#40
Well I don't know if it was Autotune, dumb luck or just getting air-time because today I managed over 16 minutes in the air (two batteries) and did nothing but smack a couple of trees and collide with a cicada.

A really short video of it at around 60m up is below - the camera is hard mounted to the frame so it's pretty violent movements - i suspect it was much windier up there...

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  • BigglesFPV
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#41
Despite having only a butane soldering iron at the moment I decided to stuff about with my dud ESC and try flashing a BLHeli bootloader onto it via the C2 interface.

It required some ugly soldering:


Then drag the whole thing off to the PC with the Arduino attached. Then connect with BLHeli software and flash with the latest (hopefully correct) Firmware.

Success!

Back down and use the blowtorch to remove the interface leads. Hook back up to the flight control and test.

Yep worked perfectly.

I'd been scratching my head about the capacitor that had been kicked off the board. It appeared to link one of the processor pins to ground, and the was another cap linking the same pin to VCC - looking at some basic esc designs with the same chipset they generally used 0.1uf or 0.47uf caps in those sort of positions. I had a few 0.1uf laying about so I blowtorched it into place



Checked it still worked and undressed the other 3 ESCs and flashed those.

Things I've noticed immediately:
Although these EMAX ESCs were BLHeli they really weren't set up like BLHeli. This meant everything I was doing setting up the quad the ESCs never responded as documented/expected. Now they do. They "brake", they beep the tunes on calibration exactly as expected, they run smoother, and much more linear sounding.

I have learnt my lesson now. Update everything the moment it arrives to exactly whatever "common" firmware people are using - just because it's a pain in the arse doesn't make not doing it OK. And even if it supposed to be ready to use and easy to update try it anyway before you build it into the frame. I spent over an hour doing this, which is nothing compared to the time spent trying to diagnose things when these damn ESCs did nothing the same as a stock BLHeli config.
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#42
After putting up video and talking about changes to this build it's probably time to document some of them.

The biggest visual change has been dumping the "decks" and using nothing but the HobbKing/Diatone X-frame.  I have the battery hung under and a PDB inside with the Micro APM on above with the compass stacked above that.  

This weighed in at 319g sans battery but in flying configuration.

   

I picked up at my Local Jaycars stores scratch and dent box a really small camera module.  While the box claimed it was 720P it's actually 648x480.  It records direct to a micro SD and needs to be supplied with power and I had to make my own button interface to start/stop recording (it's originally designed to gain on something like a rebadged WLToys heli).  I strapped it on the nose as a sort of "black box" recorder.

   

I also got sick of the battery telemetry dropping out because I didn't have the correct pitch JST 2-pin connector.  So I put 2.54mm pitch header on instead and now have battery voltage coming back to the TX so I can use the alarms on it Smile
         

The last and final thing has been to adopt Prop guards and stumpy landing legs...

         

I feel like I'm going backwards by adding the prop guards but honestly I cant afford to keep breaking them on dumb things, and my stumpy landing gear means grass is an issue as well. Hopefully with the ESCs sorted and the vibration largely sorted flying will be easier anyway.
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#43
You know you're getting somewhere when you get out to the park, fire up the Flight-controller via USB to let the GPS do its thing and within a few minutes are plugging in a battery and taking off.

First battery out I popped it up into the middle of my flying space and engaged the APM's "Autotune". This time I was able to let the entire dance finish (in about 4 minutes) and land. With APM the action of landing and dis-arm saves the tune. I also connected the tablet and captured all the new PIDs as well.

My goodness it flies so much better.

I was able to get some better video from the (rigidly mounted) basic camera and also do some testing of the advanced APM functions like Autoland.

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  • sloscotty
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#44
It seems silly but not I'm having a fair bit of fun hacking around a few of the local ovals and parks just flying (finally). However I do have to spend a bit more time just practicing all the fine skills as well.



It's nothing special compared to what others are doing and I certainly cant do it quickly but it's nice to feel I have a level of control now. Am thinking of using some kind of launch/landing mat too. Both to work on accuracy of my landings but also so I can deal with grass a bit more effectively.
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#45
Added some aluminium landing gear - used 10x3mm flat bar, 100mm height to let me under-hang the GoPro. Once I've finished moving house I'm going to get the shonky $10 gimbal working under there Smile
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