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Restoring crashed oktokopter

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Mitglied
Registriert seit: Mar 2016
Beiträge: 7
Hi All, this is my first post so nice to meet you first :-)

I am starting with a little background. A friend of mine gave me his octocopter that he crashed several times and he get tired of. I am trying to restore it. This is my first RC toy ever, so I don't have much experience with it. On other hand I am programmer with lots of experience so I decided to give it a try. I spent a lot of time reading the wiki so I thik I know at least the basic stuff.

The Drone is octa copter with delta frame like this -> http://img.hisupplier.com/var/userImages/2012-01/04/013249896_s.jpg
Flight Controller 2.1
Navi Controller 1.1
MKGPS
There is also a camera holder, but I removed so I can practice flying first.
Remote is Graupner mx-22

First I fixed the physical damages. As it turned out I was able to upload the newest version of the software to Flight controller and navi controller, the update was successful, I did the initial setup as I read from the wiki, did a compass calibration. Evertything is green, all looking good. I checked the remote control channels, did assignments, calibrated the values in neutral point of the stik to be 129. I tried to fly it today and the result was a bit unexpected - it is not hovering very well.

What I tried was holding the copter in my hand, above my head, in a big room. With the other hand I was increasing the gas very slowly. In the moment when the copter have enough power I let it go, but follow it with my hand to catch it, just in case. The problem is that it starts to move in some direction. Not very fast, but moving let's say around 0.5m/s. There is no wind in the room, it is around 2.3m above the floor. I was expecting that it will stay still. So the question is is this normal. The frame is slightly deformed, like 5-6 mm here and there, from the crashes. can this be the reason, or I can't expect such stable fligh at all? I am starting to worry how I am going to land it when I try outdoors, if it does not hover very stable. Do I need to compensate forward,back,left,right movements with the other stick or you think that there is some kind of problem? As I said I never flew drone before so I don't know what to expect exactly.

Thanks.
Mitglied
Registriert seit: Apr 2011
Beiträge: 3508
Ort: Münsterland
Hello and welcome.
A deformed frame can not fly straight. That you have to fix. Also important that you bring the FC with the ACC upgrade to version 2.2, just so it keeps good height. Have you made an ACC-calibration before the flight?
Mitglied
Registriert seit: Jan 2012
Beiträge: 380
Ort: Bramboden (Schweiz)
Hi and welcome!

This is "normal" the copter stabilizes but does not hold position over time unless you activate "Position Hold" (outdoors!) - the quality of stabilization is also depending on how good you have balanced your copter and how well the calibration of the gyros/acc is done

But since you have MKGPS, you can try out the copter outdoors and use "Position hold", this feature is using GPS an will hold the copter roughly in the same position, make sure you understand the therm "SAT FIX", MKGPS needs more than 5 satellites to establish a good positioning

Additionally you can swith on "Altitude Hold" and the copter remains at the same altitude, this is done by air pressure sensor and works indoor

Then there is "Carefree" mode... look it up

But do not solely rely on these features!

Always be ready to switch to manual mode, that means learn to fly and land the copter without navigation aid, only with stabilization aid, which is making flying already very easy as long as you hover infront of you and nose-out, but you have to learn to maintain control when the nose is pointing at you ;)
Mitglied
Registriert seit: Mar 2016
Beiträge: 7
@solutionxxl
I actually forgot about the ACC calibration, but thanks to you I made it before the first flight. I didn't get what you mean by the ACC upgrade to v2.2 is this hardware version and I have to take different board? I made all software updates using the MK-Tool so I should be with the latest software. I am thinking to get a new frame, maybe I will change the frame with Octo2, it looks better then mine. I hope that I will have no problems migrating to it.

@DRAGNET
It looks so stedy on the clips in youtube, and mine is so unstable. It always goes to some direction when I lift it off, and I have to use the remote to get it back but it seems horizontal while flying. I checked the channel values in the MK-Took all are set to 127, when the sticks are in neutral position and are going from 0 to 245. I specially calibrated the remote. I tried carefree, I liked it very much. I also know about the Position Hold and Altitude hold. I want to try the auto take off and auto land also.

Last time there was strong wind, so I broke one propeller when I was landing the second time, but next time I will pick a better weather conditions. I want to learn to fly in manual, but I'm not sure that the copter is fine, and the problem is only in my skills.
« Bearbeitet von Coppermine am 21.03.2016 18:00. »
Mitglied
Registriert seit: Mar 2016
Beiträge: 7
I manage to do stable flight and stable hovering. There were a couple of problems, but now everything seems fine. I still have one problem. I can't activate auto takeoff and auto land function. I have switch assigned, i do everything as i saw on the manual but when i change the switch position nothing happens. I notice that in the wiki there is this not saying Auto Start/Land Channel (ab V2.00) and i am confused but this text in the brackets. V2.00 of what? Software, Flight Controller, Navi Controller, Im not sure if my copter support this function, or maybe i did something wrong, but still does anybody has an idea what this ab V2.00 actually means?
Mitglied
Registriert seit: Jun 2013
Beiträge: 1224
Ort: Luxembourg
Coppermine meinte
I can't activate auto takeoff and auto land function. I have switch assigned, i do everything as i saw on the manual but when i change the switch position nothing happens. I notice that in the wiki there is this not saying Auto Start/Land Channel (ab V2.00) and i am confused but this text in the brackets. V2.00 of what? Software, Flight Controller, Navi Controller, Im not sure if my copter support this function, or maybe i did something wrong, but still does anybody has an idea what this ab V2.00 actually means?

I am very sure it refers to software version. Since software V2.00, all parts, FlightCtrl, NaviCtrl and MK-Tool on PC must be same version to run.

I would recommend you to use software V2.14.

As far as I remember, you start the motors by both stick to lower right and slowly back to the middle, micro-copter stays on the ground with motors running idle. Switch the auto start on and the micro-copter takes off.

While flying switch auto start off and micro-copter descend and land. After landing you stop the motors manually with both sticks to lower left. Note: The default landing speed of 1.2 m/s is much to fast for my taste, landing legs and cameras, I use 0.8 m/s.
Mitglied
Registriert seit: Mar 2016
Beiträge: 7
Hi Foersom,

I am with the latest version of the software on all boards. I do the same as in your description. Just when I get to the point of switching the auto start switch nothing happens. I double check the channels, button assignment POTI, everything seems fine, similar to the other buttons that are working and controlling other functions. Yesterday I found this article - http://wiki.mikrokopter.de/en/Firmware-0.90#Automatic_Starting_and_landing and there is this "The MK can now start and land autonomously. (This is only possible with new ACC board) " so I wonder does Flight Controller 2.1 has the new ACC board, because "new" is very relative term in this context :)

Thanks.
Mitglied
Registriert seit: Jun 2013
Beiträge: 1224
Ort: Luxembourg
Coppermine meinte
Yesterday I found this article - http://wiki.mikrokopter.de/en/Firmware-0.90#Automatic_Starting_and_landing and there is this "The MK can now start and land autonomously. (This is only possible with new ACC board) " so I wonder does Flight Controller 2.1 has the new ACC board, because "new" is very relative term in this context :)

Perhaps there really is a difference there. The new ACC makes the altitude control much more precise, you can land with cm precision of altitude. It is about 3 years ago that I upgraded. I recall before landing could be rather bumpy, the ACC upgrade was a huge improvement.

The good news for you is FlightCtrl 2.1 can be upgraded with ACC to become a FlightCtrl 2.2. I can strongly recommend this.

You can do this upgrade yourself or have the upgrade done by MikroKopter.
Mitglied
Registriert seit: Mar 2016
Beiträge: 7
Thanks, I will definitely order the upgrade next time I make order. Now I have another question:

I made couple of flights, the drone is stable like horizontal and hovering well, but sometimes it rotates itself over the vertical axis. I made compass calibration a couple of time, last time I did it just before the flight, but the issue still remains, I send the drone forward and at some point it rotates and of course it is heading now in different direction. Also I noticed that when I do rotate right, it is much faster than if I do rotate left. Sometimes I have to pull the joystick all the way left and it barely rotates. The remote is calibrated of course. Please give me some clue what can it be.

P.S. I am sharing a video of the last flight. I turned on the camera image stabilization and plus the vibrations somehow this strange effects with everything shrinking and expanding appeared :-)
https://www.youtube.com/watch?v=5tQG3CMDApY&feature=youtu.be

Thanks,
Juri.
Mitglied
Registriert seit: Jun 2013
Beiträge: 1224
Ort: Luxembourg
Coppermine meinte
I made couple of flights, the drone is stable like horizontal and hovering well, but sometimes it rotates itself over the vertical axis. I made compass calibration a couple of time, last time I did it just before the flight, but the issue still remains, I send the drone forward and at some point it rotates and of course it is heading now in different direction. Also I noticed that when I do rotate right, it is much faster than if I do rotate left. Sometimes I have to pull the joystick all the way left and it barely rotates. The remote is calibrated of course. Please give me some clue what can it be.

I am not sure what it could be, but some ideas:

Have you selected the correct octo-copter layout in Mixer-Setup? You have a layout with Y arms, so you should use okto.mkm, NOT okto2.mkm.

Check the soldering of two small vertical boards, and that the boards are perfectly vertical.

Do you have 15 mm rubber dampeners under the FlightCtrl?

Coppermine meinte
P.S. I am sharing a video of the last flight. I turned on the camera image stabilization and plus the vibrations somehow this strange effects with everything shrinking and expanding appeared :-)
https://www.youtube.com/watch?v=5tQG3CMDApY&feature=youtu.be

This vibrating effect is sometimes called jello. You need a brushless-gimbal or a camera with optical stabilisation e.g. Sony CX730.

Also check that your propellers are proper balanced, that can help to reduce vibrations.

Also measure wind speed at ground level. Best video when wind is <10 km/h.

Please use quote link or write @username when answering.
« Bearbeitet von Foersom am 22.04.2016 17:30. »
Mitglied
Registriert seit: Mar 2016
Beiträge: 7
@Foersom

Thanks about the suggestions. I checked the mixer setup it is set to okto.mkm, I have also the rubber dampeners under the flight controller. About the small boards - they seems vertical, i didn't measure it, but the whole flight controller board is a bit bended from one of the crashes. It's at the end of the circuit board, and there are no tracks or elements there. I am posting some pictures from the day i got it. Can i debug somehow the sensor readings using the data from the MK-Tool so i can detect problems with the orientation or soldering?

externer Link:
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I have one more question. When i switch off the hold position mode, so it goes to manual mode, what should be the behaviour of the MK. Should it hover, or i have to use the remote to compensate all the time.
Mitglied
Registriert seit: Jun 2013
Beiträge: 1224
Ort: Luxembourg
Coppermine meinte
About the small boards - they seems vertical, i didn't measure it, but the whole flight controller board is a bit bended from one of the crashes. It's at the end of the circuit board, and there are no tracks or elements there. I am posting some pictures from the day i got it. Can i debug somehow the sensor readings using the data from the MK-Tool so i can detect problems with the orientation or soldering?

The two small vertical boards looks Ok. I see the mounting hole corner of FlightCtrl are bended and broken. That should not matter, just make sure the FlightCtrl is horizontal when installed. As you manage to fly, it should be pretty Ok.

Connect the MKUSB to the FlightCtrl and start MK Tool as if you were going to update firmware. For specific components you can check there values on the MK Tool scope window (main window) on the left side. For what their values should be you must search in the wiki.

Coppermine meinte
I have one more question. When i switch off the hold position mode, so it goes to manual mode, what should be the behaviour of the MK. Should it hover, or i have to use the remote to compensate all the time.

If the ACC is calibrated, the frame is straight, the centre of gravity is indeed in the centre, and there is no wind, then the micro-copter should hover and keep it position even without the GPS position-hold on. However even small imperfections or little wind would see that it slowly drifts in one direction, which you must manually correct all the time with the RC transmitter sticks.

When you did ACC calibration, was the micro-copter perfectly horizontal?

It is possible to turn off position-hold and even altitude-hold and land the micro-copter safely. However that can require a lot of practice and can cause a crash. To learn keep the altitude-hold on, turn off position-hold and practice keeping the micro-copter at the position. If it drift away to fast turn position-hold back on.

Also learn about compass errors.
« Bearbeitet von Foersom am 25.04.2016 15:29. »
Mitglied
Registriert seit: Mar 2016
Beiträge: 7
@Foersom

Thanks for the info, it is very helpful.



Foersom meinte
When you did ACC calibration, was the micro-copter perfectly horizontal?


I used this to do the ACC calibration. I put it on the battery holder in 2 perpendicular directions, because I was not sure what is the most important part that need to be horizontal, so I choose the central plate. Maybe it is the FC but the inclinometer is too big to be put there. My frame is deformed, I fixed it as much as I can, but without special equipment there are up to 0.5cm differences. On position hold the MK is very stable, but when I turn it off I have hard time controlling it. I can keep it stable for a while but not as much as I want to. But of course there is some wind, the frame is deformed which changes the gravity center also.

I plan to get new propellers + the FC upgrade very soon, but even without them I can operate the MK stable with the position hold function. Hopefully I will be able to understand why does it rotate differently depending on the direction from the MK-Tool.

Thanks again.
Mitglied
Registriert seit: Jun 2013
Beiträge: 1224
Ort: Luxembourg
Coppermine meinte
Thanks for the info, it is very helpful.

You are welcome. Remember to help other people later.

Coppermine meinte
I used this to do the ACC calibration. I put it on the battery holder in 2 perpendicular directions, because I was not sure what is the most important part that need to be horizontal, so I choose the central plate. Maybe it is the FC but the inclinometer is too big to be put there.

That looks like advanced level meter, a simple bubble meter will also work. Yes put it on the frame / centre plate.

Coppermine meinte
My frame is deformed, I fixed it as much as I can, but without special equipment there are up to 0.5cm differences. On position hold the MK is very stable, but when I turn it off I have hard time controlling it. I can keep it stable for a while but not as much as I want to. But of course there is some wind, the frame is deformed which changes the gravity center also.

The deformed frame can be a problem for proper stability.

Check centre of gravity. Use two ~1 m strings formed as U-loop and put under two opposite inner-arms. Lift the micro-copter with the strings. Is it in balance or does it tilt to one side? A little bit tilt is Ok, but try to minimize it.

Stability without GPS position-hold. If it drifts to one side it can be the wind or it can be micro-copter out of balance. Fly the micro-copter to 3-4 m height (clearly above your head). Turn off position-hold. If it drifts to one side (e.g. west) put position hold back on. Turn micro-copter 180 degree, walk to the opposite side of micro-copter so you again stand behind it, so it is easier to control. Turn off position-hold. If it drifts off in same direction as before (west) it is the wind that push it. If it drifts off in the opposite direction (east) it is the micro-copter that is not in balance.

Coppermine meinte
I plan to get new propellers + the FC upgrade very soon, but even without them I can operate the MK stable with the position hold function.

I can recommend Graupner E-prop, they are good value for money. Remember to buy inserts.

Coppermine meinte
Hopefully I will be able to understand why does it rotate differently depending on the direction from the MK-Tool.

It is properly the frame, but check also the compass.

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