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Help with my quad.

Started by satyagupta, April 22, 2012, 07:16:23 PM

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satyagupta

Hey Guys, so today was able to test my quad :thumbsup:. Was very cautious while test. Let me tell you this quads are really very powerfull and can be dangerous too..
So i was able to get a good hover today :thumbsup: but one thing i am not able to understand is, my quad never goes straight in air :headscratch:. It kinda goes round round check vdo 2 and 3. :-\

If you check vdo 3 where my quad did a good 180 deg round this was only on throttle. I mean i only moved throttle to make it hover, the rotation and all are by quad it self. why is this happening ?? :headscratch: :headscratch:

Video 1:
http://www.youtube.com/watch?v=4iGovH5Fnq4

Video 2: be ready to hear some excited voices in the background.
http://www.youtube.com/watch?v=K0_lWMScyOA

Video 3:
http://www.youtube.com/watch?v=vXXYB3wSD4c

As you can see it was in all a very bumby flight hence one of my props gave up  :'(
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spitfire

Rotation is happening because yaw gain seems to be low. First apply some opposite trim so that it stops rotating and then correct yaw gain.
Tune gyro gains properly. You qaud was oscillating a bit so it looks like either pitch or roll gain is set a bit higher than required.

satyagupta

yaw is 20% rest 2 are 40-50% i guess.. So this is what i need to alter?

And you said opposite trim.. that will be the one which controls the YAW rotation right?
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spitfire

I assume the value you have are gyro gains.

First apply some yaw trim in opposite direction of rotation so that rotation should be stopped. Now increase the yaw gain so that it should resist the rotation.

This is how I test my quad:
(Please be very very careful while doing this and take almost precaution that props do not touch to any body part)
I hold the quad in my hand from the center of quad. Then apply some throttle. Increase the throttle to a level so that you don't feel the weight of quad.
Now for yaw gain setting, rotate the quad in any one direction. Quad should resist this motion by changing motor rpm. When you can actually feel that quad can resisting this motion, your yaw gain is set.
For pitch and roll gains, try moving quad along pitch and roll axis. Quad should resist this motion. Increase the gain till quad starts oscillating. Lower the gain by a bit just at the point when quad starts oscillating.

Now try flying you quad and see how it works. If something is not working properly then again play with gains. You have to do this several times to achieve perfect stability.

spitfire

Quote from: satyagupta on April 22, 2012, 07:55:20 PM
And you said opposite trim.. that will be the one which controls the YAW rotation right?
Yes.

Set your all yaw gain at around 40%. and then start setting as I posted above.
I have tested 3 frames and proper gains were found around 60-70%.
Though for each each frame gains are different, most of people obtain perfect gain above 40-50% so yours seem little low.

satyagupta

 :thumbsup: :thumbsup: well explained spitfire.. Thanks a lot i will try this next said steps by you. Thanks a lot  :hatsoff: :hatsoff:
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spitfire

 :thumbsup: All the best!!
Just be very careful with the props.

satyagupta

I did try holding quad in hand and testing it out. But never knew what actually i should do.. :)
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spitfire

Try moving quad (by your hand) along any of roll, pitch or yaw axis you should feel opposite reaction by quad. Increase the gain and try moving it again along same axis you should feel increased reaction from quad. Keep  on increasing gain bit by bit till quad starts oscillating. Now lower the gain a bit at this point till it stops oscillation. Do this for all the three axis.

Dharmik

Not bad test satya bro. Is it kk 4.7 plus fw? Last video is really nice. One thing with multirotor is if something goes wrong or you are about to hit obstacle, don't panic and don't decrease throttle suddenly especially when you are 10-20 feet up in the air. That was the only reason of my last crash otherwise it was flying like a dream. Well in your case you need to work on gain as spitfire said. 20% yaw gain is too low. Atlease 50% gain needed to start. For roll and pitch gain you need to correct them using single axis tuning.

satyagupta

So tried today a lots of tests.. well one thing which is persistent is "it flips or fly to the left side of the quad" dont know y.. I trimmed a lot but still sometimes it goes to the left site. About the YAW tuning as it was suggested by spitfire and dharmik bro here is what i found:

My quad was resisting roll and pitch movement but yaw... When i rotate my quad it does increase the speed of motor but i dont feel any resistance.. :headscratch: i doing anything wrong. Was not able to shot any videos, my camerawomen sister and wife both where busy with their stuff..

But once in a while i used to get a decent fly and today i got my quad to a height of 10 ft and above  ;D ;D ;D ;D i was literally dancing and jumping. But i kinda tested lots and lots of times, and my aluminum frame gave up :( last time it was props and this time it was my frame :( take a look but i have alternate frame so i will modify and post pics soon..
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satyagupta

Not able to arm my HK v2.1 any idea y?? Its working for sure.. but dont know why its not arming the board.. I can calibrate ESC by moving YAW pot to zero but not able to arm my board. Any idea why??
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satyagupta

Argh... My bad RX connection to board was wrong... :banghead: :banghead:
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satyagupta

This is the board which i am using now, http://www.hobbyking.com/hobbyking/store/__19595__HobbyKing_Mini_Quadcopter_Frame_V1_539mm.html

I have used feviquick (chutki mein chipkaye) is that good or need to use anything else?? btw whats epoxy?? and can we get that in some hardware store??
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RC_DUDE

use ariltite instant , its really good , you just hv to mix the two given epoxy solution and sets in just 5 min.

very good epoxy

satyagupta

You mean araldite instant right??
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RC_DUDE


spitfire

Increase the yaw gain and see if you can feel the resistant from quad. If you feel quad is supporting the rotation then there are chances that you have to reverse yaw gyro. Follow the procedure to reverse gyro and check it again.


spitfire

I wonder why are you mounting motor at angle? Any specific reason for doing this?

satyagupta

Spitfire dude.. "But i kinda tested lots and lots of times, and my aluminum frame gave up" so thats is how my frame gave up :giggle:

Here is what i read for gyro reversing  :help:

- Set Roll gain pot to zero.(CCW)
- Power on.
- LED flashes 3 times.
- To set Gryo Reverse, move Tx stick right/down or To normal it move stick left/up.
- Power off.
- Restore Roll gain pot.

So tx stick?? that means throttle or something else?  :headscratch: :headscratch:
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spitfire

 :giggle: :giggle:

Dont use such frame for testing. You never know when some part will came off.

For gyro reversing the procedure you are mentioning is not clear to me and also not making sense as it is not mentioning about all 3 axis roll, pitch, yaw.

I followed this link and it worked for me
http://www.kkmulticopter.com/index.php?option=com_content&view=article&id=55&Itemid=57

1: Set roll gain pot to zero.
2: Turn on flight controller.
3: LED flashes rapidly 10 times.
4: Move the stick for the gyro you want to reverse.
5: LED will blink continually.
6: Turn off flight controller.
7: If there is more gyros to be reversed, goto step 2, else set roll gain pot back.

satyagupta

Hey guys so my quad again broke something, this time its the board on which we keep HK board check pictures. Any suggestion for the replacements?? it was 3mm ply which i guess will break every time if there is a hard landing. What do you guys suggest i should use..?
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Dharmik

Satya bro try glass fibre or something similar to that. 2mm ply is thin so breaks easily.  You can also try smiley balls as a landing skid to withstand impact.

satyagupta

Hmm glass fiber?? where would i get that??? online any links?? any LHS stock that??
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Dharmik

Search in local market, have you seen exam boards? The transparent one which comes in different thickness. I am thinking to use them but need skill to cut them.