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#21) 
 Post subject: Re: Tricopter project
PostPosted: 06 Nov 2011 19:11 
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Location: Lot et Garonne, South West France
Mine built as well, did some 'clamped' down motor test, the motors went immediately to full throttle, so went and had a cup of tea and think. After tea I had a look at the Tx only to find the the Throttle Hold switch was on :oops: Strangely enough, the 6ex doesn't beep when switching on with switches enabled in heli mode, also the Swash was set to 120 mode, changed it to 90, after these little mods all seems to work OK. I wanted to try a flight but its been windy and pouring with rain for two days now so will maybe try when weather clears up.

What do you think of this....:

http://www.ebay.co.uk/itm/KK-MK-Multi-Copter-Y6Tcopter-Folding-KIT-SCORPION-Y650-Y6T-Y-type-MultiCopter-/150683993063?pt=Radio_Control_Parts_Accessories&hash=item23157743e7



Lee

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#22) 
 Post subject: Re: Tricopter project
PostPosted: 06 Nov 2011 19:27 
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I have mine in plane mode which works fine. Only downside is the throttle hold switch doesn't work on the DX6i, dunno why they chose to do it that way.

When you run it (without props!) in your hand and you swivel and sway it, will the correct motors spin up and down? Better do a dry run on that otherwise it might be a short maiden.

That copter frame looks pretty cool, but 6 of everything is expensive. Might make a good FPV platform as one failed motor will probably not crash it.

Ordered an aspusb programmer the other day so I can flash the KK boards myself. Here's what looks like a fairly easy to use flash tool: http://lazyzero.de/en/modellbau/kkmulticopterflashtool Even runs on Mac.

- Mark

Edit: oh yeah, and the KK boards from http://www.multircshop.com/ shipped on Friday. See how good they are once they get here. Will probably be a month or so...


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#23) 
 Post subject: Re: Tricopter project
PostPosted: 06 Nov 2011 20:22 
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I did the initial test without props to test stabilisation although the KK board was used before so there shouldn't be any change, but as I have re flashed the board thought I'd check anyway. So all ready for the maiden next week.



Lee

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#24) 
 Post subject: Re: Tricopter project
PostPosted: 12 Nov 2011 14:41 
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Unfortunately mine won't energise with Tx set at 'plane' mode. had to put things off for a few days as I had to build my new Sukhoi which is now ready for its maiden, too windy though at 12mph for a maiden, ( got an anemometer as well) Anyways, I have today managed to try out the Tricopter. In an ideal world this would have lifted off and hovered, but sods law dictates its not an ideal world, trti lifted off and immediately fell over to the right. after several attempts continued to do same thing. I can only guess at a motor mismatch, I may have to buy three matching motors before trying again.

Got a new motor and nano-tech lipo from HK for the Sukhoi, I was hit with customs duty, nearly 15 euros. :shock: Never had to pay duty before on 'hobby parts'. :?:



Lee

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#25) 
 Post subject: Re: Tricopter project
PostPosted: 12 Nov 2011 18:55 
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Location: Moresnet, Belgium
I have a lot going on as well. The Ryan has the crash damage repaired and gotten her new motor mount. Just need to put on the motor and ESC now. And the Slick 360 Micro arrived but I have just looked at the parts so far. Seems nice enough.

Spent almost 2 hours chasing down a copper bug on the tricopter today. I figured the cheapo motors I got were duff so replaced them with RCtimer 2212/8s. One of them still wouldn't spin. Tried out two other ESCs, nothing. Wired the offending motor's ESC directly to a receiver without going through the KK - nothing. Finally I removed the extension wires I had made and presto! it spun up. Turns out I got a batch of 3.5mm bullet connectors that are just rubbish. The plugs are made so the piece you solder to rotates inside the bullet itself. Never seen something like that before and it's obviously not a good idea. And of course I'm out of 3.5mm connectors so meanwhile I put in the ESC from the Ryan.

Anyhow, after all that it would arm and all three motors spin up. When I tried it out it would not lift off vertically but was trying to maintain about a 30 degree downward attitude, sliding across the floor. A few clicks of up elevator trim sorted that out. And it flies! With the trim pots on the KK board at 1/3 open it is very unstable in its own downwash, getting better above 2 feet or so but still very twitchy. With the pots at 2/3 it oscillates scarily in clean air. Just above 50% seems to be best. On the Tx I set dual rates to 75% and expo to 25%.

I managed to fly around the garden a bit under the floodlight as of course it was dark again. The frame definitely needs some colored bits to make it a bit easier to recognize where's front and back. Just after the 10th or so liftoff one of the ESCs hit low voltage cutoff. I was keeping it low and above the grass so no harm done, but this thing definitely needs a low voltage alarm!

All in all so far so good. It will be a while until I'll be able to fly it smoothly enough to even think about putting on a camera. But it's quite good fun. It's sort of like a big FP heli at this point.

Meanwhile I'm looking at the Openpilot Copter-Control which seems to be a very nice controller with self-leveling function (and a host of really cool stuff like GPS control). Their hardware is very hard to come by at this time though... --> http://www.openpilot.org/

- Mark

P.S.: Happy belated birthday, Lee! :)


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#26) 
 Post subject: Re: Tricopter project
PostPosted: 25 Nov 2011 11:41 
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Location: Moresnet, Belgium
Coming back to the issue of stabilization; after some reading it is clear that the HK and KapteinKuk boards do not feature self-stabilization. I have looked at a few alternatives available of which there basically are two types:

1 - all-in-one control platforms that have stabilization (and sometimes return-to-home, hover, follow-contour, and autopilot functions) built in
2 - add-on stabilization platforms

Of variety 1 there is a plethora of platforms to choose from. Openpilot Coptercontrol and Ardupilot are two that will also work on tricopters, the Fyetech FY-31/FY-91 do not support tricopters, only quads and up.

Variety 2 includes systems such as the FY-20A. They tend to be somewhat cheaper since the KKs are really cheap now but generally cannot be upgraded/expanded to include autopilot functionality. The advantage of having stabilization separate from control means you can just take the system and put it into any airframe that operates off the normal Rx outputs. Also you only have to buy one stabilizer and can put it into whatever aircraft you want to use for FPV instead of having to buy and configure one for every aircraft you intend to use.

With the FY-20A you connect it between the Rx and the KK, wire for wire. Pretty simple.

Here's a video each showing a FY-20A stabilizing a KK-controlled tri and quad, I think it's quite impressive:



I'm planning on getting one of those FY-20As to experiment with. Basically right now I only want a bolt-on box that will stabilize the copter if something goes wrong. Take the hands off the sticks and it will hover kind of thing.

The next step would then be to get a system that has autopilot and is able to follow contours for some low-level FPV and aerial filming. The Openpilot would be nice but hardware is almost impossible to get. The Ardupilot Mega seems the way to go although it is a bit more involved and also twice as expensive. Provided it works well the FY-20A will then go into one of the helis as a save-my-hide insurance. :mrgreen:

- Mark


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#27) 
 Post subject: Re: Tricopter project
PostPosted: 25 Nov 2011 15:00 
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Joined: 28 Jun 2009 14:22
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Location: Lot et Garonne, South West France
Hi Mark, I tried my tricopter last week but can't get any sense from it, first of all, as soon as it left the ground it would yaw to the right and not correct, no amount of trimming or altering gyro sensing would correct this. Also has a tendency to roll to the right and try to fly backward. I did program the board as a tricopter. in short, its not stabilising.

Quote:
it is clear that the HK and KapteinKuk boards do not feature self-stabilization.


This is where it gets confusing, you say the KK board is not a stabiliser? according to what I have read, and tested, the KK board should should function as a flight stabiliser, for example, if I drop right wing, right motor speeds up to correct! If tail drops, tail motor speeds up! Surely this attitude correction is stabilising the aircraft.

Quote:
With the FY-20A you connect it between the Rx and the KK, wire for wire. Pretty simple.


I already have the FY-21 AP with return home function, are you saying if I connect this between the Rx and KK controller, this will stabilise the tricopter platform? So what's the purpose of the KK board? Have you got a phone number?

As far as I'm aware, the FY-20 and FY-21 are not designed to stabilise anything but a fix wing aircraft, i.e., there is no throttle input yet strangely enough there is a throttle out.


Confused..... :?



Lee

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#28) 
 Post subject: Re: Tricopter project
PostPosted: 25 Nov 2011 21:43 
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Joined: 11 Jun 2011 16:11
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Location: Moresnet, Belgium
Hi Lee,

the KK board will counter external factors such as wind pushing the tri around to a certain extent, but it will not actually try to maintain level flight. You can test that by holding the tri in your hand with the props spinning, then slowly tilting it. There will be no reaction from the KK. If you are a bit more abrupt it will indeed spin up the sinking prop, but that is not really enough. You can set the pots to be more sensitive but then the system will soon overreact and start to wobble.

Basically the gyros in the KK will only react to acceleration. Systems like the FY-20A do more, they actively try to assume a flight attitude which they see as level. This was a bit of surprise to me as well, I also assumed the KK would do that.

Regarding your problems I suggest you try the following:

0 - check CG. The tri needs to very nearly balance on a finger placed at the intersection of all three arms. Adjust battery position as required to achieve that. Also, make sure the direction indicator of the KK board is pointing towards the front.
1 - set the Tx to plane mode (not heli) to take the swash plate mixing out
2 - put the tri on a hard surface, at least 5x5 meters, tail towards you, and adjust all three pots on the KK to mid position
3 - spool up to a point without taking off, then apply rudder. If it doesn't turn the right way, reverse the channel in the Tx
4 - likewise, try aileron and reverse if the wrong prop rises (one of them should spin up)
5 - same for elevator, try and reverse if required
6 - spool up a bit more until the tri wants to lift off and starts sliding around on the floor. See if you can control it with elevator/aileron/rudder. Note which way it wants to slide (e.g. front and left). If it wants to yaw, apply trim on the rudder stick to counter that.
7 - now, throttle up to bring it off the deck quickly by 2 feet or so, applying stick as required to counter the movement from #6 (in this case, back and right).
8 - adjust trims on the Tx as required (in this case, trim down and right a couple clicks)

That should get you airborne. After that, land it and adjust the pots on the KK. Basically, turn them up (clockwise) a bit at a time and test fly until you notice the whole thing become skittish. Then back them off a bit again. That would be the maximum setting you can have.

Note though that the whole thing flies pretty much like a heli at this point. Letting go of the sticks means it will start to drift and sink randomly.

Quote:
I already have the FY-21 AP with return home function, are you saying if I connect this between the Rx and KK controller, this will stabilise the tricopter platform?

As far as I understand their manual, the FY-21AP only works with fixed-wing aircraft. Though there's nothing in the FY-20A manual about copters either. Fyetech say the 21 is an enhanced 20 with additional functionality (which may or may not be true) so it might work as well, I just have not been able to find a single post anywhere saying something about the combo FY-21AP + tricopter. Or any copter for that matter. What I did find was this: http://www.helifreak.com/showthread.php?t=250810

Maybe drop Fyetech an email and see what they say?

Quote:
So what's the purpose of the KK board?

Basically, do the mixing of the motors as required and provide some limited stabilization functionality, but no self-leveling.

Quote:
Have you got a phone number?

Yes but I'm not at home right now. I'll PM you my office number, you can call me on Monday if you want.

Quote:
As far as I'm aware, the FY-20 and FY-21 are not designed to stabilise anything but a fix wing aircraft, i.e., there is no throttle input yet strangely enough there is a throttle out.

Yes, they do not control the throttle. The FY-20A only has aile/elev/rudd channels, plus the mode selector. The manual clearly says it will take care of attitude control but the pilot has to take care of airspeed. In the case of the KK board that's ok because throttle is mixed onto all three throttle channels.

- Mark

Edit: on a technical note, it seems the FY-20A actually uses accelerometers, while the KK boards have gyros. That would explain the difference I guess.


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#29) 
 Post subject: Re: Tricopter project
PostPosted: 26 Nov 2011 12:44 
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I change tx to accro as suggested, last time I did this the KK wouldn't initialise for some reason, did this time, only problem was the throttle was reversed resulting in me having a three inch gash on the back of my hand, :oops:
As regards the instability problem, I have now found the reason, the tail motor doesn't spin as fast as the other two. I have mismatched motors, the tail is a WS 480 925kv. the other two are I think are 950kv. Also ESC's are different in that tail is a 40A the other two are 35A and different make. So I'm now going to spend some money and get 4 matching motors and ESC's and try again.

I may also try and fit the FY-21AP when motors arrive. Been foggy here for three days so no flying, now I'm stir crazy. :lol:



Lee

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#30) 
 Post subject: Re: Tricopter project
PostPosted: 26 Nov 2011 14:32 
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Posts: 337
Location: Moresnet, Belgium
EB52 wrote:
I change tx to accro as suggested, last time I did this the KK wouldn't initialise for some reason, did this time, only problem was the throttle was reversed resulting in me having a three inch gash on the back of my hand, :oops:

Ouch. Yeah, these things bite. Momentary lapse of reason and I had two pinkies slashed for a week as well.

Quote:
As regards the instability problem, I have now found the reason, the tail motor doesn't spin as fast as the other two. I have mismatched motors, the tail is a WS 480 925kv. the other two are I think are 950kv. Also ESC's are different in that tail is a 40A the other two are 35A and different make. So I'm now going to spend some money and get 4 matching motors and ESC's and try again.

Probably a good idea. I have two types of ESC on mine but all three motors are the same. Seems to work well enough.

Quote:
I may also try and fit the FY-21AP when motors arrive.

I suggest you send them a mail, they seem to be responsive. I asked them about which of their products would work on a Y3-type tricopter, and received an answer this morning.

Turns out they have two sets of firmware for the FY-30A (which, as opposed to the 20-line is user-upgradeable), and the multi-rotor firmware supports Y3, x4 and +4 copters. And it doesn't need the KK board either, it will control the 4 ESCs or 3 ESCs+servo directly! Software and manual is available here: http://shop.fyetech.com/product_info.ph ... ucts_id=67 (the manual is in the software .rar archive and shows how to wire stuff up).

Based on that information I'm a bit torn whether to wait for the FY31AP which, going by the 20 series, might be a 30+autopilot and thus may support Y3s as well. The specs seem a bit limited compared to the Ardupilot but it's cheaper and ready to use. See what the manual says when it's released in early December.

- Mark


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