New Build and Test Flight

[rwilabee]

I just finished installing flying and testing my quad with the DJI WK-M. What a great unit. I set my flight mode switch to do Manual, ATT, and GPS and also wanted a Return to Home and Land Switch. So what I did was set my Throttle Hold switch to go in to failsafe when you switch it. It works great now I have 4 flying modes. I can also abort the auto landing just by switching out of Throttle Hold. I leave the throttle at 50% or more when I go in to Throttle Hold for Return to Home. After it lands it shuts down the motors, pretty cool. I have included some pics of the quad which is a Hover Things 550mm Frame, the DJI WK-M, SII-2212-885KV Scorption Motors, DYS 30 amp ESCs, 11x4.7 props, GoPro 1080p camera. I did modify the Hover Things Frame to give me an extra level (3 now) in case I need it sometime.

If you go to my youtube page you can see a video called Field Auto Landing which I took while flying around our flying field and then clicked the Throttle Hold Switch for Return to Home and Land. In a second Video called Auto Landing you can see the auto landing taken from my Cellphone Camera, I did have my finger in the way but you can see the landing just fine. Next time I'm out at the field I will reshoot the video. I have a few other videos on Youtube taken from the quad.

http://www.youtube.com/user/rwilabee

Rich


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[Droider]

You dont muck around do you!.. What TX are you using and have u got the latest firmware on it

Nice build btw

Dave

 

[BorisS]

I like it Rich.

It drifts off quite strongly to the end of the landing procedure was there wind ? I just remember my first failsafe auto landing attempts and i dont remember if it really landed were it locked the sats but it went straight down with no drifts.

http://sprealinvest.at/failsafelanding.mov

Just wondering since i didnt have so many tries yet and if that drifting off happens from time to time i wont ever do it with cam equipment on. Otherwise WKM is stable with GPS hold on for you ?

Thanks

Boris

 

[rwilabee]

I see what you mean about your's coming straight down. I probably had a 2 mile an hour breeze not much. It seemed like it came more straight down before I did the update the day before but it is hard to remember as I didn't film it. I did notice one thing. My GPS antenna is mounted in the rear and I put +8 for the X GPS instead of a -8. I'm pretty sure it should be minus eight with the antenna in the rear. The other thing is that I don't have CG directly in the middle of the plate, it is about 1/2" in front of dead center. If it is better to have CG directly in the middle of the plate. To have my CG dead on center I will have to add 2.5 oz of lead that would be 1.25 oz at the end of two of the arms. My camera is mounted in the front so that throws the CG off Center. It seems pretty stable with GPS hold on for me but I can only compare it to the Fyetech FY91Q that I replaced and it didn't hold well. Any other ideas just let me know and I'll check it out.

How do you guys get your gear listed at the bottom of your posts?

Thanks
Rich

I like it Rich.

It drifts off quite strongly to the end of the landing procedure was there wind ? I just remember my first failsafe auto landing attempts and i dont remember if it really landed were it locked the sats but it went straight down with no drifts.

http://sprealinvest.at/failsafelanding.mov

Just wondering since i didnt have so many tries yet and if that drifting off happens from time to time i wont ever do it with cam equipment on. Otherwise WKM is stable with GPS hold on for you ?

Thanks

Boris

 

[BorisS]

Hi Rwilabee,

thanks for the Info the CG should be the reason, strange although that at GPS hold it seems to work without any drift.

You can change you signature under setting right top next to my profile and than look to the left in the sub menu it should say edit signature.

Thanks!

Boris

 

[rwilabee]

Do you think it is worth adding the extra weight to make the CG dead on center.

Thanks

Rich

Hi Rwilabee,

thanks for the Info the CG should be the reason, strange although that at GPS hold it seems to work without any drift.

You can change you signature under setting right top next to my profile and than look to the left in the sub menu it should say edit signature.

Thanks!

Boris

 

[BorisS]

I cant really answer this since i don't now what the DJI algorithm is all about. If you know were the CG is than it should be enough to mount the IMU accordingly to the point that might not be center physically of your frame but the CG.
It should work that way. Some setups have a 1 KG or more cam on it so the CG shifts, I have to be able to compensate for this by again the mount config, I cant add another KG some were to equal it out.

But its all about testing and maybe finding a good way to find the actual CG. I am already thinking about it for my CS8

 

[rwilabee]

In the manual under Mounting it says to balance the CG directly on the center plate. So I'm wondering if that is why we have to do the X, Y, and Z axis so if you don't have the IMU or GPS mounted dead center it will compensate for where they are mounted in reference to the CG. The more I think about it the more it makes sense for a stable flight just like an airplane that the quad needs to be balanced on the center plate. I added the extra weight to test it out and balance it. During a hover test I was using 80% of battery life for 10 minutes of hovering. Now I'm using 90% of battery life for the 10 minute hover. I haven't got to try the failsafe yet to see if I get less drift.

Have you messed with any of the Autopilot basic parameters. Mine are still at default. I wonder if adjusting any of those would lessen the drift on failsafe or are those mostly for hover?

Thanks
Rich

 

[BorisS]

What are your gain settings at the moment, basic and attitude ? Before thinking about different props or other changes to your frame. I would start to play around with the basic gain.

 

[rwilabee]

My Basic is 100 Pitch 100 Roll 100 Yaw 100 Vertical
Attitude Gain both settings are 100

 

[BorisS]

okay i would start to alter those take the basic gains up to the point where either you see oscillations on the frame or you have an improved flight behavior and your happy. And with a Quad you can bring up the attitude gain especially if there is no wind around.

Really try those settings before you buy anything to improve it !!!

 

[rwilabee]

Do I take them up one at a time or move each one a little but at the same time. I flew today and it flies great but on failsafe it was all over the place coming down. It did not come down straight. We did have about a 5 to 8 mile an hour wind.


Thanks
Rich

 

[BorisS]

Strange one ! basic gain take up 10 20 % at a time for all of them, you can leave vertical out. SAme for attitude gain, although i would send a vid to the DJI guys asking them what the reason could be. If he holds position in GPS hold why should it not when autolanding.

You have to consider one thing autolanding on a flatsurface might work even when it dirfts of. At the moment you autoland in high grass oder a bumpy surface, the landing gear will catch itself and the copter will probably tilt over, props gone etc.

Boris

 

[rwilabee]

I'm up to 120% on the basic and no oscillations yet so still testing. In GPS mode it does move in small circles but just a little. The other interesting thing and maybe it is normal is that when I click in to failsafe it climbs in altitude before it starts to decend.

Thanks
Rich

 

[DennyR]

I think that is what it is supposed to do!

 

[Gunter]

I would deffo make sure CG is in the middle of that plates. It just makes a lot more sense, that will make sure all the motors do the same amount of work. Totallycommitted had a CG problem this weekend at our meet, and it made a big difference when he moved his battery from the left hand side to underneath in the middle.

Gunter.

 

[rwilabee]

Hey Boris....

I sent the video to DJI and they said that a drift of 2 to 3 meters is acceptable. They said that to help the drift I should calibrate each time before flying.

Rich

I like it Rich.

It drifts off quite strongly to the end of the landing procedure was there wind ? I just remember my first failsafe auto landing attempts and i dont remember if it really landed were it locked the sats but it went straight down with no drifts.

http://sprealinvest.at/failsafelanding.mov

Just wondering since i didnt have so many tries yet and if that drifting off happens from time to time i wont ever do it with cam equipment on. Otherwise WKM is stable with GPS hold on for you ?

Thanks

Boris

 

[Tahoe Ed]

In the manual under Mounting it says to balance the CG directly on the center plate. So I'm wondering if that is why we have to do the X, Y, and Z axis so if you don't have the IMU or GPS mounted dead center it will compensate for where they are mounted in reference to the CG. The more I think about it the more it makes sense for a stable flight just like an airplane that the quad needs to be balanced on the center plate. I added the extra weight to test it out and balance it. During a hover test I was using 80% of battery life for 10 minutes of hovering. Now I'm using 90% of battery life for the 10 minute hover. I haven't got to try the failsafe yet to see if I get less drift.

Have you messed with any of the Autopilot basic parameters. Mine are still at default. I wonder if adjusting any of those would lessen the drift on failsafe or are those mostly for hover?

Thanks
Rich

I also am doing a new build. I was thinking about your comment and my test mule, an ArduCopter. On that unit I mounted the IMU and GPS/Compass on the X and Y axis in the center of the copter. It was rock solid. On my RC Carbon frame the GPS/Compass is mounted is mounted behind the center of the frame. It drifts in GPS hold. I may try and remount it above the IMU and see if that helps. Thanks for the insight.