Hello everyone,

After much discussions here regarding the design and parts selection with all your help, I finally built my first quad with a KK2 board, Flysky TH9X Tx and with 1.5kg payload setup. It flies with plenty of power and is well balanced on the hand crafted aluminum frame, but I have a few problems. I have calibrated the ESC's and also performed the gyro calibration.

1.When the quad takes off, it doesn't take off straight up, but drifts to some side, so I have to correct the tilt by leveling the aileron elevator when the copter is 5cms above ground and then only I can lift it or it will keep drifting more as I throttle up. All the trims have been adjusted with receiver settings showing zero and it is not a frame balancing problem as the next time I take off, it drifts to some other direction which I again have to correct. Are all quads like this or do I have to do something like autolevel to make it steady ? I strongly feel the board has to autolevel itself rather than me doing all the leveling.

2.Also if I move the pitch stick a bit forward and leave it back to idle, the copter keeps pitching forwards and wont stop until I pull the rod a bit back to stop and level it, is it like this?

3. Can someone tell me how to adjust the throttle response curve to make it hover easily ? as now it either goes up or goes down and to keep it hovering, I need precision throttle adjustment which seems like a nightmare when the whole craft keeps drifting as said in problem 1 and 2.

4. Is there an altitude hold function anywhere in KK2? I would like to climb to a particular altitude and then hold it there so that I can move it around without making it go nuts.

5. Will autolevel solve my first problem? I have assigned it to channel 5 on my tx and it responds well on the receiver settings but if I trigger the switch while in flight, it goes to somewhere on its own which I didnt check out much as i switched it off immediately fearing a crash.

6. As the whole craft was hand built from aluminum, the landing gear too was made in such a way so that a bit hard crash will crample the metal landing gears to absorb some shock. Now that I feel confortable after 1 hr of flying and crumbling it several times saving the whole setup from many crashes, planning to build something more rigid with styrofoam padding. what kind of a setup would you all suggest, should I mount it from the central axis where I have 8 nut-bolts holding the  tubes using square metal plates or shud I mount them to the arms? mounting to the arms have a risk of bending the frame on an accidental crash or hard landing but will avoid flipping the craft while landing rough while central mount will save the frame from bending but might flip the craft as the foots will be closer.

7. during esc calibration (F20A) I set tx on, throttle full, 1+4 pressed and power on, says esc calibration and beeps in several patterns for about a minute or 2 and then stops beeping, I then pull the throttle to zero and it beeps once and still the kk2 display says calbrating escs even after 2 minutes after the last low throttle calibration beep, is everything calibrated then? can I release 1&4 even if the kk2 is showing calibrating esc but the esc beeped once for low throttle?

Hope someone can help me tune this machine

hi,

haev been using similar setup with kk2.0, i too have same problems u defined.

first of all to solve the drift problem at takeoff. u need to start motors and ensure all are running at same speed.
then give enough throttle so that the quad lifts immediately and then control the throttle such that the quad is at eyelevel.

once u are out of ground effect then the quad will be stable. if u try to give throttle slowly the ground effect takes effect and hence u find the quad dragging on the ground. i have learnt with exp. also ensure that the kk2.0 is not fixed firmly with double side tape and not vibrating.

the kk2.0 is a basic board and will do what told. its not upgradeable. there is not gps addon facility and hence the quad will be drifting in winds. unless flow in calm weather.

ur design is good just ensure that all motors are straight and not tilted to any side. i am building similar frames from 1/2" Al Sq and 1mm fiber glass sheet.

regarding esc calibration do it individually i.e connect the ch 3 on rx and not wit h kk2.0 setup. i follow this method.

you willl have to upgrade to the Mutiwii crius boards which are upgradeble.

see my pics below.

Hey Joseph,

Build looks fantastic, i really liked the frame. Did you make it our buy it?

To answer your questions:

1. Drift while take off is totally normal. Your quad will be more stable after you get it about 6ft in air. I had same issues but later on i realized that its not a issue. Its like the gyros need some space to correct itself. Hence a perfect stability after 6ft in air.

2. Yes its like that, and you can change that behavior by changing gain values. I dont rem but i had a good document about it, and it had explained this fact very nicely.

3. If your craft drifts even when its in air then adjust trims. Try to calibrate your gyros by placing your craft on a totally flat surface ( i did notice some improvements) Drifts can also be noticed if there is some wind. Depend on the gain, it depends how resistance your craft is towards wind.

4. Never tried altitude hold but yes it has that function, but with alt-hold you can either go up-down or a 360 deg rotate.

5. Never tried so don't have any idea..

6. Mounting to arms is good idea but yes in a hard crash you may bend or break the arms. So central landing gear is good i would say

7. That is right, you hear a confirmation tone when you move the throttle to 0 and calibration is done. Check the F20A manual for the throttle calibration tune. When you hear the confirmation tone, leave the button 1 and 4 but please confirm again, you get the calibration instructions on the KK2.0 board itself.
  I would like to add one more point which was suggested to me by Dharmik bhai. First calibrate the ESC individually and then all of them together using board.


EDIT:

BTW i found this very helpful manual http://www.hobbyking.com/hobbyking/store/uploads/475200704X68736X56.pdf

Also check this very good and helpful video

Quote from: satyagupta
haev been using similar setup with kk2.0, i too have same problems u defined.

first of all to solve the drift problem at takeoff. u need to start motors and ensure all are running at same speed.
then give enough throttle so that the quad lifts immediately and then control the throttle such that the quad is at eyelevel.

They are not starting at the same time. I calibrated thrice but via the kk2 board, so I guess that is the problem. No matter how many times I calibrate the esc, motors 1 and 3 start together and then 2 and 4 starts after that. I knew it was the problem, but didnt know how to fix it, thanks for the lead!
The KK2 is mounted on styrofoam which is inturn is mounted by the edges, so will completely dampen the shocks, you can check in my first pic.
The frame is exactly symmetric, I checked several time while building, made from 3/4" aluminum tubings.
And the KK2 should do well for me, I just need it to autolevel using the gyros, gps and all maybe later
Your crafts look great! good job and thanks a lot for the guidance

Quote from: sbajare
Hey Joseph,
Build looks fantastic, i really liked the frame. Did you make it our buy it?

Thanks buddy. I built it myself from 3/4" square aluminium tubes and some aluminum sheets and then wrapped it in carbon fibre. Total cost is less than 80rs but did a lot of work.
Wind drift is fine, I just need it to be controllable after take off The trims are all adjusted to zero, I guess individual esc calibration is needed. Yeah shud be the ESC. Thanks a lot for taking the time to answer all queries individually, really helped me let me see what I can do

To make all motors start at same time . Go to misc settings in kk2 and increase minimum throttle from 10 to 12 . Or if motors still don't start at same time 14 should so .
For stability caliberate your kk2 accelerometer placing quad on a level surface . And use trims . It will always drift a little .
Your gain settings might be a little low. Try increasing it a little.
Esc caliberation is easy . Turn on tx, giv full throttle , power on the quad while pressing 1&4 button on kk2. One or two beep . Put Tx throttle stick to minimum , another beep/s.. Done in about 25 seconds.
Suggestions - flash kk2 with 1.6v. If using 1.2v, self level is almost non existent in it And flash escs with Simonk. Flashing esc will make your quad much more stable as u can double ur gain settings . Motor positions don't matter much. The board will even fly a quad with accidentally offset arms .

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Wow, that was the kind of info I was looking for. Thank you.
Will try increasing the minimum throttle and see. Sensors are calibrated well, trims are all zero. I have heavy drift in a random direction, will check the gain. Where do i set it? In the tx or the kk2?
ESC calibration is still confusing. I tried direct receiver to esc and put throttle to full and powered on. the esc starts beeping a 1sec delay short pulse 5 times, then a double beep, immediately I put throttle to zero and then 2 short beeps but no long single beep. Is this correct? When I connect via kk2, same thing happens.
after trying some onboard settings, will look into the firmware upgrades for the fc and escs. Thanks a lot.!

Gains settings in KK2 board.

For the ESC calibration please check the ESC manual. Have you flashed your esc to simonk?

The manual has only info about manual tx based esc programming and nothing about calibration, maybe I should find a different version. So far have not flashed the esc's or upgraded the KK2, just wanted to know if this programmerhttp://www.ebay.in/itm/ATmega-ATtiny-51-AVR-ISP-USBASP-USB-Programmer-Downloader-/181191321725?pt=LH_DefaultDomain_203&hash=item2a2fd8287d would help me upgrade both the kk2 and esc if I make the pin connections?

Yea thats the one you need.

About the manual,

http://grab.by/ph54

music 1 is for Throttle, when you hear 4 beeps then move the throttle to lowest value and you will then hear one confirmation tone.

Thanks a lot. If it is as per your said procedure, my esc's have not had a successful calibration so far. Will check it out.

Flash kk2 and esc first. Half your problems will go away. Manual not needed once esc is flashed.
http://www.rcgroups.com/forums/showthread.php?t=1675613
Esc caliberation video etc is in the link

Half my problems were due to esc calibration. Till now I was following the wrong procedure and guessing with the wrong beep codes and so they were never calibrated properly. Yesterday managed to get all 4 motors calibrated together via kk2 as told here and now they start at the same time. Also increased throttle minimum to 12, atleast the difference in starting time is not noticable now, could not test fly as it was late night. KK2 is running the old v1.2 . Have ordered a USBASP programmer yesterday, will flash the KK2, esc and T9x all with the best stuffs as soon as it arrives in 2 days.

Good work joseph,

What Pravesh have suggested is good but then i did flew my quad for over 6 months with the very first version of KK2.0 FW and non SimonK ESC. It did gave a good performance. But then SimonK ESC are very different. They pass data to motors faster than non SimonK ESC which results in very smooth and stable flight and a very good control.

So what i want to say is first fly the quad with non simonk ESC then if you feel that its not stable or smooth then flash the ESC.

EDIT: a very good video to understand what SimonK does to your ESC

I've gathered all the necessary stuffs to flash the esc and kk2, just waiting for the programmer to arrive. In the meanwhile dissembled the quad partly to fix a better landing gear and add a protective gaurd for the kk2 to protect from crashes. Flashing the kk2 to 1.6 is the first priority to get the auto-level to work and to get better stability after reading the changelogs and the addition of newer algorithms in newer versions. will flash esc's also along with it as everyone tells that they are excellent. Was reading about PID tuning past 2 days. will get it too tuned to the best level, Im gonna make this thing as stable as possible without drifting much or flipping. ALso read that the new autolevel algorithm works best with draggy crafts like this.. Thanks for all the advice. will keep you all posted

Flashed the KK2 to v1.6, autolevel works great, but i guess Im happier with it turned of now as the craft is very much controllable. Also flashed the ESC's with simonk's fw and I tried hooking up the esc directly to the receiver and now the motors respond and rev like an F1 engine! such quick response and then I tried another esc with stock fw and it was so dissapointing. I tuned the throttle curve, pitch curve as well as PI gains and now I am able to control and hover the craft in medium winds at 10 feet on my 4th flight! Yesterday flew for 15mts without crashing or flipping and all landings were smooth and not bouncing off. Thank you everyone, The PI tuning can get better I hope.

post some images or videos dude

Quote from: joseph.alukka on August 16, 2013, 10:35:28 AM
Flashed the KK2 to v1.6, autolevel works great, but i guess Im happier with it turned of now as the craft is very much controllable. Also flashed the ESC's with simonk's fw....

happy flying. flashing can do wonders

Did you build your own jig to flash the ESCs ?

And which part of Kochi do you live/fly ?

I'm a total newbie to this hobby but an experienced DIY enthusiast, so I am gonna explain what I took care of during the build so that anyone with better suggestions can help me out, or maybe this would help other newbies while they build.

This one below shows from where I started. Wanted a slick looking craft with stability for areal photography, so the frames are 500mm motor to motor. After the initial drilling and finishing. The fuselage panels are from an old PC smps case. They are light but strong and easy to cut.



The pic below shows the frame after some fake carbon fibre wrapping and everything gets bolted up. All the basic parts are bolted on with washers and spacers but the wiring has not been done.



The craft before first flight with all wiring done, landing skids in place, batteries loaded, calibrated and basic checks done.



One of the several take offs from the first airtime session. The craft flew without breaking anything or flipping, however was drifting in random directions and was very hard to hover and land as it kept bouncing.

This pic below of the craft about 10ft high, was very hard to hold altitude as I am a newbie.



The throttle response curve on my TX which I tuned to assist me in hovering.. Startup is at zero and as normal propellers start spinning at about 20%, goes up linearly til about 40%, then I flattened the response to allow fine adjustment of throttle from 40-60%, that is why the slope is at a lower angle, you can fine adjust throttle in that region without bumping the craft up and down with quick responses in that region. The high region is again linear which I wont be using for now and I have limited the peak to 85% as I dont want to make it shoot into the sky. Be sure to set the throttle curve after esc calibration or the esc will scale the throttle back to 100%  even though it may show 85% on the TX. This curve needs better tuning, but only after I study the craft's response and tune the PI



The new FC protection hull I added yesterday to protect the KK2 from the worst that can happen if it flips and falls from a height. The thing is a heatsink holder from an old pentium 3 processor ;-) Looks like it was crafted for this project It is very strong and heat resistant, bolted to the frame.



The pic below shows how I mounted the KK2. The KK2 is mounted on the cover of the foam box it comes in from factory, it was punched with the right holes, spacers pushed into the holes to prevent it from compressing and then bolted with washers from either sides. This foam is then bolted to the frame from the other edges to eliminate all vibes, but still keeping it steady. Each of the 8 nuts were hotglued to the bolt after tightening to prevent it from coming off due to the vibrations. I lost a pair of nutbolts holding the foam pad to the frame and the board started tilting. Now it will never happen again.

Next to the buzzer connector, I soldered a metal pin to the 12v hole for voltage monitoring alarm and then plugged in a male to male connector cable, you can see the red connector.



The battery voltage reading on the KK2 from the above connection. I use a dedicated individual lipo cell monitor and alarm, but still didnt want to leave out a feature which was available. The lcd is not cracked, I have stuck it using double sided tape on the back and it the tape showing up on the scree, looks like I'll have to take it off.



The flashing jig I made to flash the esc. This is what first came into my mind when I saw the pads on the esc. You can see the pads exposed through the flap on the heat shrink tube. This jig was connected via M2M connecting cables to the USBasp.



The whole flashing setup without removing the esc's but props removed.



And that was my first multirotor build with a hand built frame. I'll make a video of the flight on sunday and put it up. All suggestions welcome. The only thing pending now is to build a better landing skid as the one presently on was made to crample easily and absorb shocks on my maiden flights. Now that I can land properly after the updates and few sessions, I dont need it anymore. You can see the crampled landing skids in the last photo. Once Im atleast intermediate in flying, will load up a camera and a servo for tilt function. Some aircraft type flashing leds also coming up!

Have a great day and happy flying!

Quote from: anwar on August 16, 2013, 12:46:08 PM
Did you build your own jig to flash the ESCs ?

And which part of Kochi do you live/fly ?

Yes, you can see it in the above pics. I had a plan to use a hard disc multipin contact which connects the head to the hdd board, but the one I had was missing from my stuffs. And I am from angamaly

Hi Joseph,

Really nice build  . Everything you have crafted is very well , great job on your first build !

I will recommend one change and this is last thing you may like to do.. only if your quad still not performing good in terms of stability

Noticed you are using emax fc 28x series motors , these motors are good , powerful , cheap , popular and perform well individually, however together it may vary from other slightly. I do have these motors and used these on fomies.
This is my personal opinion  Others may have different experience. I am using Turnigy 2830 with 30amp esc on my quad and it's very stable out of the box.

Thanks,
-Vinayak

Thank you for the suggestion Stability is good now, it is getting better with the tuning each day and I have had no problems so far. Buying a whole new lot of motors and esc's gonna cost a lot for me, so I guess I'll have to stick with this for now But it sure will be on my list of upgrades! ONe reason for choosing these motors were the output power per amp .. It provides a lot of thrust but draws only 14A and gives me a good flight time, so will keep this for now and keep in mind your suggestion for the next build if I do build one

Hey joseph Fantastic, build i must say that... Try to upload a video of it soon...emax is good still Use lower kv motors to get the quad very stable in air and also for better flight time..
All the best.. wish you many safe landings...