Help needed

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Help needed

Postby Didimon » Sat Mar 03, 2012 11:54 pm

Hi all,

First of all I'd like to introduce myself. I'm Daan de Meester, Dutch, 40 years old, married, 2 sons (5 and 7 years old) and for a daily living I'm a commercial pilot for a Dutch company. Pleased to meet you all!!

Always been interested in model flying and especially helicopters. Started with some simple small 3 channel helicopters but soon wanted the 4th channel (roll) and found out that this is quite difficult. So I got an airplane (Parkzone T-28 Trojan) and after a few weeks I'm in full control of this airplane. Fun but still I was looking for something more and was confronted with the Blade MQX quadcopter which is exactly what I was looking for. Because of my enthousiasme I got the opportunity to buy all the parts for a MultiWii quadcopter at once and after 1 week of neglacting my family ;) of a lot of reading an trying, I finished building one.

And now I need help because I'm unable to understand the intelligence of the PDE file..... and after the first try today with propellors I found out that I really need to stabilise everything but don't know how or where to start.

I have a Quad X configuration.

Here is my setup:

Arduino MiniPro board
Original Wii motion sensor
Original Wii nunchuck
Sparfun usb reader
Spektrum AR6210 receiver
4x brushless BL-Motor 2827-35 (robbe)
4x Hi Model FLY-20A-proSB

All mounted at this frame: http://www.rc-helipower.nl/?cat_id=823& ... temID=7845

LIPO 3-2200 ZX 25C (robbe)

Uploaded the standard 1.9 version of MultiWii to the board and I am able to use the MultiWiiConf_1_9

If I read the board you will see the attached images (one with the nunchuck active on the gear switch and one without)

All respond to inputs, as well from movements as from inputs on my transmitter (Spektrum DX6i)......

Who is willing to help me out here with knowledge? Help is appreciated very much and I know that I'm a noob an probably I will ask stupid questions...... please forgive me for that but one thing that will make me happy is to fly a MultiWii quadX copter. ;)

What do I need to do or know to get this thing flying??

Best regards:

Daan
Attachments
snapwii2.jpg
snapwii1.jpg
Didimon
 
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Re: Help needed

Postby Didimon » Sun Mar 04, 2012 12:04 am

PS, I forgot to mention that I use Groupner E-prop (L) and (normal) of 10-5"

(L prop)................(norm prop)
..X (cw)...................X (ccw)..
....\.........../\......../...........
.....\..........|......../............
.......\........|......./.............
........----------------...............
....../.................\.............
..../....................\............
.../......................\...........
..X (ccw).................X (cw)....
(norm prop).............(L prop)..
Didimon
 
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Re: Help needed

Postby mr.rc-cam » Sun Mar 04, 2012 1:03 am

and after the first try today with propellors I found out that I really need to stabilise everything but don't know how or where to start.

Welcome aboard. You didn't say what the exact problem is. So that is the place to start. I realize that you want the model to be more stable, but some details about what you are experiencing would help the experts here.

Comments:

1. Your build choices look fine. However, I couldn't find any MWC user comments about the FLY-20A. Be sure to confirm it is rated for the 500Hz PWM update rate used by MWC.

2. The default PID's should allow you to hover. If the model oscillates in flight then reduce the PID values a tiny bit until the oscillation stops.

3. Some folding frames have poor rigidity and the motors can torque along the arm axis, which affects flight performance and PID tuning. So grasp each motor and try to rotate/twist the arm. The arm should be sufficiently rigid and not allow unnecessary motor torquing/rotation.

4. The props size is appropriate. I expect that a watt meter will show about 450 watts at full throttle with them. This is a good sanity check, so measure electrical parameters if possible.

5. Balance the props. Do not skip this step! Your local (or online) hobby shop will have cheap tools that are designed for this task.

6. Confirm that the convex side of the props is on top. If reversed, the props will have less thrust (no, the air flow will not be reversed if the props are "upside down").

7. Be sure to calibrate the ESC's. There are endless discussions about how to do this.

8. Do not mount the sensors rigid on the Arduino shield. They should be mounted using self adhesive servo mounting tape or equivalent. The wires connecting to the sensors should be flexible, short, and very lightweight gauge (to reduce vibration issues).

9. Read the MWC FAQ and all the related links Again and follow the instructions provided. Read the FAQ many times until your eyes bleed.

10. Your model may be fine; It may be untrained fingers that need more time at the sticks. What I mean is that, despite how easy a Quad looks to fly, and all the endless videos on YouTube that seem to confirm they fly themselves, consider it all an illusion. It looks easy because the good pilots practiced for many hours.

- Thomas
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Re: Help needed

Postby Didimon » Sun Mar 04, 2012 9:23 am

First of all, thank you for the reply, well appreciated.

Most of the comments I understand and are taken care off. The frame is very stable and rigid. No torquing/rotation possible.

I was expecting that it would hover (to start with) but when I increased throttle a little bit, the quad flipped over very agressivly. Holding the quad with half throttle, it wanted to climb (I was surprised in the force). As soon as I started to move a bit the thing goes crazy. This is what I mean by 'not stable'. Expecially with the nunchuck activated I expected the quad to make corrections so it would go to hover (horizontal and stable) position.

I will continu to read, my eyes bleed already ;)

Also next week I will go to a guy who can measure things with the right equipment.

I'm not a pro in flying but spent many hours with the Blade MQX quadcopter which is my motivation for the multiwii quad.

Best regards,

Daan
Didimon
 
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Re: Help needed

Postby bill516 » Sun Mar 04, 2012 12:17 pm

Start off in gyro only mode, acc off, no props and GUI running. Throttle up to about half way and then use Tx trim to balance to motors, using graph on on GUI. Once you have set the tx trim dont touch it again. To balance in acc mode take off props and use GUI again but this time use the acc trim function. Motors dis-armed, left stick to top left use right stick to move trim in direction you require to balance graph in GUI.
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Re: Help needed

Postby Didimon » Sun Mar 04, 2012 1:56 pm

bill516 wrote:Start off in gyro only mode, acc off, no props and GUI running. Throttle up to about half way and then use Tx trim to balance to motors, using graph on on GUI. Once you have set the tx trim dont touch it again. To balance in acc mode take off props and use GUI again but this time use the acc trim function. Motors dis-armed, left stick to top left use right stick to move trim in direction you require to balance graph in GUI.


Hi, also thanks for willing to help me....

Not sure I fully understand, gyro only = nunchuck off, right? So I start the engines (no props), GUI running and I throttle up about half way. All 4 engines are running and indicating approx. 1500.

What exactly do you mean with "use Tx trim to balance to motors, using graph on on GUI"?

Sorry for beeing such a noob but this is what I have done:

1. downloaded the arduino 0023 software
2. downloaded the MultiWii_1_9
3. compiled that (without changing anything in all the codes) and uploaded it to the Arduino board succesfull (Uploading done with no errors)

I can start the engines with either stick full right position and see the correct commands when I roll, yaw or pitch the frame.

Regards: Daan
Didimon
 
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Re: Help needed

Postby bill516 » Sun Mar 04, 2012 3:32 pm

Gyro only - nunchuck off

Above where it says nunchuck there are four bars that represent the rpms of the motors. Use the trims switches on the Tx, the little ones near your sticks to get the motors to balance i.e all four motors at about the same rpm, throttle trim should be all the way down and stay there. The trim for aileron will affect the motors on either side, pt and stbd, while the elevator/pitch trim will affect the motors at the front and back, fore and aft.

Trim works just like the real thing, if you are left wing low you trim to push the aileron down and raise the wing, with a quad it will increase the rpms for the motors on the that side and or decrease on the opposite side, pitch works the same way on fron and rear motors.

If motors are lagging or speed up before the others then use the subtrim in the TX menu to get them to start about the same time.

This is the advantage of using the GUI and no props, 1 it wont fly up in the air and possible hit you, been there ,done that, got the scars. 2 you wont brake anything trying to fly and trim at the same time.

When you come to try with props you will have some idea of what is going to happen when you get to flight revs so it should not leap up on one side and flip over.

When I first powered mine up with, it was tri-copter but same principle, and the GUI method was not known about then,I held it in one hand tightly and powered up slowly, I could feel that it was starting to lift on one side so trimmed to get rid of that. Eventually I got it so that I could get nearly full power and the tri was just trying to push my hand up equally on all motors.

http://multiwii.googlecode.com/svn/bran ... -57721.pdf
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Re: Help needed

Postby Didimon » Sun Mar 04, 2012 4:43 pm

That makes sence, I'm gonna try that later today, will let you know.

Many thanks so far.
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Re: Help needed

Postby Didimon » Sun Mar 04, 2012 8:38 pm

Hi again,

I trimmed the throttle indication full down, just take a look:

http://www.youtube.com/watch?v=D_EbnvkLTpw

Any comments on this so far?
Didimon
 
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Re: Help needed

Postby bill516 » Sun Mar 04, 2012 9:35 pm

You've still got some vibration there that why the rpms are all oscillating. If you pick the quad up does it improve. You need to get the trace line to be flat or maybe a little squiggle at higher scales. Grab the slider on the scale bar and it will display higher resolution, its very sensitive you only need to move it to about 1.5 from the 1 it is at. It does seem better that what you were describing ealier on so you are getting somewhere. The vibration can be a pain to cure or you can just hit lucky and get it first time. I cant tell from the vid if your board is mounted straight on the quad or if you have some insulating material under it (foam
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Re: Help needed

Postby Didimon » Sun Mar 04, 2012 11:06 pm

Hi,

Next few days I will try to improve the vibration issue, now the warthox board is mounted on the frame with 2 screws with foam in between but via the 2 screws it is in direct contact with the frame ofcourse which will be of influence.

I'll try several things, first of all with the warthox board de-attached and hold seperately stable from the frame, after that I'll try several ways to mount it to avoid vibrations.

Keep you posted.

Once more and than I will let it rest: I can't express myself in gratitude feeling towards all of you who are willing to help me out here.... It might become a long topic with a lot of stupidity from my side but if the result is a flying MultiWii quadcopter, I will be very happy!!

Regards:

Daan
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Re: Help needed

Postby bill516 » Sun Mar 04, 2012 11:18 pm

No problem if we cant help each other then we may as well pack it in altogether and go live in caves again.

BTW the only stupid person is the one who doesnt ask when they dont know.
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Re: Help needed

Postby mr.rc-cam » Mon Mar 05, 2012 3:44 am

now the warthox board is mounted on the frame with 2 screws with foam in between but via the 2 screws it is in direct contact with the frame of course which will be of influence.

Eliminate the screws. The sensors need good isolation from the frame to damp the motor/prop vibrations. As mentioned, self adhesive servo mounting tape or similar adhesive-backed foam tape is fine (1-2 layers depending on the foam thickness).

FWIW, I use silicone gel pads that I found in the shoe department at a local store; they are about 1cm square x 3mm thick and feel like fresh baked gummy bears. Some high performance R/C gyros use a similar silicone mounting material, but my shoe stuff was 1/4 the cost. Of course adhesive-backed foam tape is fine too.
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Re: Help needed

Postby Didimon » Mon Mar 05, 2012 10:54 am

Hi,

tested this morning with several pieces of foam and thanks to the idea mr.rc-cam I found some silicons in the house..... not sure how my wife will react when she finds out but who cares :lol: :mrgreen:

I managed to get a very stable indication of all 4 engines but the next problem is that is should be mounted on the frame so I'm thinking now how to fix that because as soon as the warthox board is on the frame (with foam and silicons in between), again some vibration shows in oscillation.

Anyhow, I know it's possible and now that I have seen it work, I won't rest again till fixed..... as soon as I managed, I'll let you know (and show it).
Didimon
 
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Re: Help needed

Postby Didimon » Tue Mar 06, 2012 12:16 am

Hi,

Member Wilco1967 contacted me via a PM and I spoke to him for more than one hour on the telephone this evening.

With his help I now understand a lot of things which were abracadabra for me until before the telephone call. With all the new information gathered I continued the proces tonight and will be continuiing the next couple of days.

I should be able to fly (hover) the QuadX MultiWii copter as soon as I'm finished with mounting things together. All settings have been tested and also the software is beginning to make sense.....

Keep you posted on my progress and I'm sure I can use some help more so thank you all for your time an patience.

Regards:

Daan
Didimon
 
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Re: Help needed

Postby bill516 » Tue Mar 06, 2012 9:30 am

Glad to hear your moving forward. Its quite satisfying when some thing that confuses you starts to make sense. Its even nicer when poeple you are trying to help let you know how they are getting on.
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Re: Help needed

Postby Didimon » Tue Mar 06, 2012 11:33 am

Yeah!!

Didn't sleep much last night, but I managed to get the thing flying (for the first time). Simply and carefully hovering....

http://www.youtube.com/watch?v=JFwFlzb9508

I will continue to finetune ofcourse.

Next step is the Nunchuck.... no clue how this works and didn't test it (yet) but very happy I got so far....

Can anybody tell me how to use the nunchuck? I can activate it with the gear switch on my transmitter and shows in the GUI but what is it that has to be done exactly?

Regards:

Daan
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Re: Help needed

Postby bill516 » Tue Mar 06, 2012 3:46 pm

Well considering what you wrote in first post I thnk we can say we have got a problem out of the way. You will find if you get outdoors or a more open space that it will respond differently, less dirty air, and if you get out of the ground effect it will become more stable. Though I have said to a few people you need to be able to manage ground effect as you've got to go through it when you come back down, unless you do it the quick way but that tends to break things.

Re the nuchuck you need to calibrate it then set your trim using the GUI and the sticks to trim, shown on the pdf I linked to, and set the motor rpms to be the same then its case of up and down and trim and up again untill you get the quad to hover in acc mode. Its just the same as trimming the TX trims but you use the sticks and listen to beeps, if you have a beeper, just watch the led if you havn't. There are some vids on u tube of acc trimming they give a good idea of what to do and what you should see. If you've got it right then when you flick from gyro to acc the quad should not do anything, it should stay where it is.
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Re: Help needed

Postby Didimon » Tue Mar 06, 2012 10:02 pm

Hi,

Took it outside today:

http://www.youtube.com/watch?v=MX1wE7OWtCo

Amazing stuff..... really great to fly.

Very happy now for the moment, finetuning and pimping the quad is the next step 8-)

Keep up posted, thanks!
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Re: Help needed

Postby Didimon » Thu Mar 15, 2012 9:08 pm

Hi all,

I'm most happy with my MultiWii quadcopter, had to wait for a delivery of propellors which arrived today and immediately I flew again with great pleasure. Meanwhile learning a lot of stuff regarding this material.

For now it's ok and I'll practise as much as I can. I consider my quadcopter as a practise device now and as soon as time is available again (season is starting at my company) I'll build another one with all the available features.

Many thanks for all the help so far.....

Best regards:

Daan
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