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Jul 25, 2007, 11:30 AM
Multicopter/FPV/UAV/HAM
_helitron_'s Avatar
Quote:
Originally Posted by PeteSchug
I'm not even sure what is being built and I am intrigued.

Or maybe fascinated.

I will drop in from time to time until I know what it is and if I want one.

Pete
Hi Pete,

nice to see you here too, we know us from the FPV forum !

Here you can watch some neat videos of the MikroKopter

http://www.mikrokopter.de/

on the left there is a point "Videos".

Don't want to intrude in this thread but I've also just started to build such a MikroKopter and got last week the first parts, to see on the attached pic. Due to my current UAV/FPV project with the Cularis I unfortunately don't have so much time for this new neat gadget and can't build it in such a extreme short time as Arthur . But I hope in the next few weeks I'm able to assemble this very interesting aircraft and because I'm a R/C heli flyer since more than 20 years I'm very curious about the behavior in the air compared with a heli.

Cheers, Erwin
Last edited by _helitron_; Jul 25, 2007 at 04:52 PM.
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Jul 25, 2007, 04:43 PM
Registered User
This is a awesome little flying thing!

I was thinking of getting an hurricane heli for ap, but now i know better.

An mk is the nest thing iŽll be buying! I will watch this thread with huge interest

Peter
Jul 25, 2007, 04:55 PM
Registered User
Thread OP
No intrusion. The more souls, the merrier. Feel free to intersperse your build into the same thread. That might nicely concentrate knowledge here

I just got my motors and ESCs from TowerHobbies. Now that looked like an American site. But the package arrived from HongKong, and taxfree at that At about USD 25.00 per combination of a TowerPro A20-22L motor + 25A ESC, I am not complaining. Motors seem very complete and not bad quality for the price on first inspection.

Slight let-down with the ESCs. They are wat Quax on his site (http://home.versanet.de/~b-konze/low...18a_regler.htm and yes it is all in German) terms the 17A type ESCs (http://home.versanet.de/~b-konze/low...I2C_Umbau.pdf), but with the MOS-fets doubled (which indeed would increase there capacity by about 50%), and without the lipo cell 2 wire plug or the programming pads. So a bit more work to modify them. And I hope his conversion and HEX files will work for the 25A. We-ll find out this weekend I guess.... If the conversion does work, I-ll of course post a description in English here. I shouldn't be pulling more than 20A max, so the 25A should be sufficient margin.
Jul 25, 2007, 05:06 PM
Registered User
Thread OP
By the way, Helitron aka Erwin, I notice that you aren't showing the compass module. You will need that if you want to go to GPS controled flight. If you only want to use the GPS to record position of fotos you could do without, of course.
Jul 26, 2007, 12:12 AM
Multicopter/FPV/UAV/HAM
_helitron_'s Avatar
Hi Arthur,

call me Erwin please .

When I've build a little bit of that stuff I'll post some pics also for sure. Then I'll also join the german MikroKopter forum because I'm a native german speaker .

Yes, I've planned to add GPS plus compass (compass module is in the moment still integrated in a little robot, another hobby of mine ) and I think I'll give later then the alternative software from Pitschu with Kalman Filters

http://forum.xufo.net/bb/viewtopic.php?t=5980

a try. You know the GPS part of the original Holger firmware is not available in the moment and when you plan to use the MikroKopter for GPS controlled heading hold or waypoint following it's necessary to write your own GPS part or to use an alternative software (for example Pitschu).

By the way, you're working really hard, Arthur are there also any news with your ARM7 project ?

Cheers, Erwin
Last edited by _helitron_; Jul 26, 2007 at 12:17 AM.
Jul 26, 2007, 07:43 AM
Registered User
Hello Arthur, I am new to this forum, I am however a member of the Rcuniverse.com form ever since I bought my Draganfly. Every since I saw the quadrokopter I am just mesmerised at the whole concept. I would surely want to build myself one but would need a lot of guidance from someone like you. Would you help???

Rgds
Roland ( uganda)
Jul 26, 2007, 10:23 AM
Multicopter/FPV/UAV/HAM
_helitron_'s Avatar
Hi together,

just got the next parts for the MikroKopter incl. some spare props .

First I've purchased the standard motors for the MikroKopter already, a Roxxy type from Robbe, but had bad luck. Two of them have had a failure (short-circuit from housing to all three phases), so I returned all four Roxxys and decided to switch to the very good (but more expensive) AXIs.

The glassfiber parts are for joining both the square aluminum tubes together to a cross. They have also holes to mount the flight controller and the four brushless ESC.

The compass module is a CMPS03 from Devantech in UK (have I borrowed from one of my little robots ).

Cheers, Erwin
Last edited by _helitron_; Dec 06, 2007 at 12:47 PM.
Jul 26, 2007, 05:43 PM
Registered User
Thread OP
Didn't have much time today but I think I managed to coax the Mikrokopter controler to reasonable health. There were several IC feet on the processor, opamp and linear accel which may not have been soldered properly. And one condensator may not have been positioned ideally. So a bit of reheating here and there and pushing down some IC feet.

The roll and nick gyro and acceleromater curves now overlap nicely. The jaw gyro still doesn't show much movement (about from -10 to +10 max, but for all I can tell it is healthy. Checked every part of the circuit between the gyro and the processor and all contacts are go. The Z acceleration offset seems a bit high at about 749 (all other gyro and acc offsets are around 500) but again, I can't find any faults in any part of that circuit and it does show reasonable response on up and down movement and in fact goes from full positive to full negative on turning over the mikrokopter with the little monitoring screen showing a drop to about 300 so it does seem to pivot around 500. So I guess this is OK. One of the problems here is that the manual is a bit short on what normal values should be. Will do the ESCs tomorrow. I-ve had another look at Quax's manual and that should be reasonably straightforward, but keep your fingers crossed. If it does work I should have my first testflight this weekend....

As my A20-22L, which are in roughly the same power and kV bracket as those Axi's, but cost about 1/4 as much , should be able to handle 12x6 props I ordered some counterrotating pairs from ToddsModels. Be interesting to see how much lift at what amps those will provide. They are also probably a bit less prone to breaking than the GWS EPP1045s.

For the EPP1045 lipoly.de does offer a brushless rearmount adapter for the Roxxy and Axi motors with a 3mm thread so that you don't have to drill them out. Haven't seen that anywhere else. The A20-22L's however have a 4 screw instead of 3 screw rear mount. I did read that someone just cut of the 5mm axle, and drilled out the center from the inside to fit a 3mm bolt.
Jul 26, 2007, 06:18 PM
Registered User
Thread OP
Regarding the Q4Arm7 project, I did finally get the ET-ARM header PCB with PLC-2119 processor last week. It is about half the size of the PLC-2214 header in part due to not having a USB interface and not having additional memory. It's also a lot cheaper. So for now that's the prime target for integration. I mounted it and the whole array of sensors on an experiment board, and also the parts for a 3.3V PSU. Next step will be to wire all the parts together and then try work on the programming. Footprint currently is about 3x as large as that of the MK controler, and even a bit larger than of the UAVP controler. But this is just temporary wiring (all prints are connected with little pins and sockets) to be able to do the programming and testing. If I get this to work I'll compact it a bit more, e.g. by locating some sonsors below the header board. Should be able to get it down to about the size of the UAVP controler. Sensor array currently includes 3x MLX90609 gyros, 3 axis accelarometer, 3 axis magnetometer, airpressure sensor, GPS. And that is with off the shelf breakout boards. Someone who could rework the circuit into 3 PCBs (1 horizontal, and 2 small ones vertically at right angles, should be able to compress all of this into about the same size as the MK or UAVP PCB. I may even add in a 10cm-6m ultrasonic sensor for accurate altitude hold at lower altitudes although some say the ultrasonics don't work well due to all the turbulance below the Q4s. But I may locate the sensor below the camera housing. Might get it out of the worst of the turbulance that way. In the very long run --if I get this to fly well-- I may even try some optical sensor to e.g. identify marked landing spots or support even more accurate position hold.

Of course getting the MK into the air has first priority. But I do have some annual leave coming up soon. So I should have a bit more time then, certainly if the weather remains as poor as it has been over the last months. Yes, I do have a >> 100% full time job next to this. I just don't sleep much
Jul 26, 2007, 09:39 PM
Registered User
Arthur,

Here is my MK, this one has been flying over Hoofddorp since may this year.

Hereby some pointers to save you some troubles;

Motors:
The combo A20/22l + 12x6 is not optimum or stable.
I allready did some homework on the Hacker A20-22L last year when I researched them for my tricopter.
Check this data:
http://www.peakeff.com/MotorDetails....ID=2539&v=10.5
The "sweet spot" size prop for this motor I found to be 10x4.5 -10x5.
Even though the the kv value is off by about 200 (compared to Axi) this is allready a big difference.
The APC 12x6 is more efficient than an EPP1045 though, see my excel sheet for values.
Best match for a 12x6 prop is a 700-830 kv motor.

Props
Two factors play a large part in props and stability:
- RPMs during hover or flight
- Prop weight
With a bigger size or higher pitch prop the RPM of each motor is lower during hover or flight (opposed to EPP1045), the lower the RPM the less stability control the multirotor has.
Prop weight, same thing here, the bigger mass of the bigger prop is harder to accelerate and slow down. One might think it is just a few grams but you will see the difference immediately when flying an EPP1045 (6.5 gr) vs APC12x6 (24 gr).
When flying with 12x6 prop and the MK you would need to turn the "gyro P" to 100 and "Gyro I" to 120 with the kopter tool. With these values the MK is still wobbly and even worse: the lower these values the bigger the wind sensitivty becomes.
So I do not advice on using MK with 12x6 props.

Ultrasonic Detection:
Ultrasonics have no issues with turbulence hence they "see" through air.
The problem is surface, they need a solid surface to bounce the signal back.
Since most people fly or start on grass, ultrasonic detectors are almost useless (been testing this since januari) since grass scatters the signal and sensor readings are very erratic.
So only use it if your landing/target zone has a smooth/hard surface e.g concrete/pavement/ice & car roof.
Same goes for infra read/IR...

Greetz

Peter
Jul 27, 2007, 01:25 AM
HeliAP'er!
Hogster's Avatar
That looks so cool with the A620 hanging beneath it like that!! What sort of flight times do you get with that setup?

I must say the determination and persistance of you guys astounds me - keep up the great work!!!

Cheers,


David

PS. Doesn't having the battery that high up affect how the Quadrocopter flies? Or does the centre of gravity need to be on (or as close as possible) to the plane that the motors are located on?
Last edited by Hogster; Jul 27, 2007 at 01:43 AM.
Jul 27, 2007, 01:41 AM
Registered User
Thread OP
Thanks Peter !!! I actually bought the TowerPro A20-22L's on the basis of the mix of weight, shaft diameter and power output. Most motors with a bit more power actually have thicker shafts which becomes a problem withe the EPP1045 props. And the EPP1045 props are far from ideal if RTF weight goes over about 1.5kg according to most posts on this. At the TowerPro prices I may actually order some slightly more powerfull motors and some 30 or 40A ESCs with slightly higher kV to match the 12x6 props better. Of course that is IF the ESC mod works. With the APC props the shaft diameter isn't much of an issue and the slightly larger motor weight would help balance the higher prop weight.

Interesting design, your MK. Like a Jeep. Purely functional. But then isn't that what multicopters are about ;=)

What I think many of us could really use is some more extensive info on the normal range of values when testing the MK with the MK tool. I.e. for each sensor what would be the normal offset in the little "LCD window" and what would be the range of values you would expect with certain test movements. And how should the curves roughly look. The current manual only provides some info for the gyro's and tells you that the nick and roll gyro and acc curves should closely match. But little or no info about the Z-Accell or jaw (gier) gyro, nor about the air pressure sensor. After having gone through hoops, and originally thinking my jaw gyro was defective, I-ve now come to the conclusion that the values I'm seeing may be normal after all. but it might not be a bad idea for all to post some data and images of curves. I-ll try and do that this evening or tomorrow for my values.
Jul 27, 2007, 04:50 AM
Multicopter/FPV/UAV/HAM
_helitron_'s Avatar
Quote:
Originally Posted by Arthur P.
For the EPP1045 lipoly.de does offer a brushless rearmount adapter for the Roxxy and Axi motors with a 3mm thread so that you don't have to drill them out. Haven't seen that anywhere else. The A20-22L's however have a 4 screw instead of 3 screw rear mount. I did read that someone just cut of the 5mm axle, and drilled out the center from the inside to fit a 3mm bolt.
Hi Arthur,

have ordered such adapters from lipoly.de and they are on the way to me. Post pics when I've got it.

Erwin
Jul 27, 2007, 04:59 AM
Multicopter/FPV/UAV/HAM
_helitron_'s Avatar
Quote:
Originally Posted by Djago
Arthur,

Here is my MK, this one has been flying over Hoofddorp since may this year.

Hereby some pointers to save you some troubles;

Motors:
The combo A20/22l + 12x6 is not optimum or stable.
I allready did some homework on the Hacker A20-22L last year when I researched them for my tricopter.
Check this data:
http://www.peakeff.com/MotorDetails....ID=2539&v=10.5
The "sweet spot" size prop for this motor I found to be 10x4.5 -10x5.
Even though the the kv value is off by about 200 (compared to Axi) this is allready a big difference.
The APC 12x6 is more efficient than an EPP1045 though, see my excel sheet for values.
Best match for a 12x6 prop is a 700-830 kv motor.

Props
Two factors play a large part in props and stability:
- RPMs during hover or flight
- Prop weight
With a bigger size or higher pitch prop the RPM of each motor is lower during hover or flight (opposed to EPP1045), the lower the RPM the less stability control the multirotor has.
Prop weight, same thing here, the bigger mass of the bigger prop is harder to accelerate and slow down. One might think it is just a few grams but you will see the difference immediately when flying an EPP1045 (6.5 gr) vs APC12x6 (24 gr).
When flying with 12x6 prop and the MK you would need to turn the "gyro P" to 100 and "Gyro I" to 120 with the kopter tool. With these values the MK is still wobbly and even worse: the lower these values the bigger the wind sensitivty becomes.
So I do not advice on using MK with 12x6 props.

Ultrasonic Detection:
Ultrasonics have no issues with turbulence hence they "see" through air.
The problem is surface, they need a solid surface to bounce the signal back.
Since most people fly or start on grass, ultrasonic detectors are almost useless (been testing this since januari) since grass scatters the signal and sensor readings are very erratic.
So only use it if your landing/target zone has a smooth/hard surface e.g concrete/pavement/ice & car roof.
Same goes for infra read/IR...

Greetz

Peter
Hi Peter,

really nice construction your frame, I like it ! Do you have any vids of your MK (I mean a ground video not onboard) ?

Cheers,

Erwin
Jul 27, 2007, 08:49 AM
Registered User
hi Arthur, Congratulations on getting this far. I am very keenly watching your progress and will surely want to build a quadrokopter. I hope you will help me in my endevour.
Roland


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