Auto landing
- Thread starter rwilabee
- Start date
DucktileMedia
Drone Enthusiast
And we cant get ours to come down at all. Someone must know the answer to this ??? I see no options in settings so it must be a fails safe setup issue in the tx. But we tried almost every combination.
quadcopters
Quadcopters.co.uk Drone Specialists
Have you got it set to go Home and Landing , or just hovering ??
Geoff
Geoff
quadcopters
Quadcopters.co.uk Drone Specialists
Are your Mounting and COG settings all accurate?
Good point my COG Z setting probably changed when I added the Gimble. It was fine with the FPV but when I added the gimble is when it started coming down too hard. I'll double check it.
Thanks
Rich
Thanks
Rich
Ok let me get this into my head as I'm new to all this, I know about the GPS X,Y,Z settings, and the IMU which I have smack dead centre so X and Y will both be set at 0 cm. So it comes to the Z setting, from where do i take the measurment from the frame? is it half between the base plates, and is it half of the IMU?
There is no set position, it depends where the center of gravity on that axis is and that will depend on what you have above and below the center plates. Usually a gimbal with a DSLR on it is going to lower the CoG for the Z axis significantly, if you have a setup like on the CineStar frame with the battery weight up above the electronics on the top plate then it tends to offset some of the weight of anything below the centerplates.
The trick is finding a way to accurately determine where the CoG is on the Z axis for any given frame, one way to do that is hang the multi by the end of an arm with it fully RTF, battery(s) included and see where a vertical line dropped from the point the frame is suspended from crosses the frame itself, that should be the CoG for the Z axis. You may want to hang it from a couple of arms and see where the vertical lines intersect to get a better idea of where the point is.
Once you know the CoG then the measurement is supposed to be to the center of the IMU, so there's going to be some amount of estimation involved as I haven't yet found a way to do it very accurately, +/- 1 CM is what DJI says it should be.
Ken
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It would be good if DJI or somebody could knock up a video clip on how to find the CoG for the Z axis of the IMU, instead of us all estimating, that way the controller is not working double time to compensate the estimations.
Thanks for that Ken I'll give that a try, just need to understant it a little bit more.
Rob
Thanks for that Ken I'll give that a try, just need to understant it a little bit more.
Rob
DucktileMedia
Drone Enthusiast
HA! get DJI to help? thats a good one. thats like asking Holger if he wants to do Lunch or asking Jeff from Xaircraft to call you back or getting a paid return from HobbyKing or expecting these things to fly out of the box. 
Joking aside, it would be great to see a true way to determine this. Robert from DJI USA told me how but it really didn't make sense to me when I tried it out.
Joking aside, it would be great to see a true way to determine this. Robert from DJI USA told me how but it really didn't make sense to me when I tried it out.
HA! get DJI to help? thats a good one. thats like asking Holger if he wants to do Lunch or asking Jeff from Xaircraft to call you back or getting a paid return from HobbyKing or expecting these things to fly out of the box.
Joking aside, it would be great to see a true way to determine this. Robert from DJI USA told me how but it really didn't make sense to me when I tried it out.
Thats why it would be a very helpfull way from DJI to have a video clip to make us all understand it a little bit better. As on average we are all playing with £2000 + rigs.
Gunter
Draganflyer X4
Z axis is easy. Load up and hold your multi up as it would fly. Now turn it through 90° so that the booms are pointing up and down, left and right. Top is against your chest and landing gear away from you. Now try and balance it on your hands by holding it, say, under the booms. If it tries to tilt away from you, move your hands further away, so maybe under the lower plate. (all the while on its side) If it tilts towards you, balance it on a point closer to you, so that when you balance it, it could go in any direction as easily as the other. You won't get it 100% accurate, but pretty damn close.
I'll make a quick video to try and explain this further tomorrow!
Gunter.
I'll make a quick video to try and explain this further tomorrow!
Gunter.
UAVproducts
Formerly DJIUSA
What I do is put the frame on the floor so its straight up and down (Perpendicular). Mark that spot.
Lift frame off the floor, let it sway and come to a stop. Set on floor, Mark that spot. Measure the difference of the two spots.
That is the Z Axis.
Seems to work for me.
Lift frame off the floor, let it sway and come to a stop. Set on floor, Mark that spot. Measure the difference of the two spots.
That is the Z Axis.
Seems to work for me.
Seems to me, that Robert's method would create a number double the value of Ken's method.
Or is it late and I'm too tired to think about this right now?
DucktileMedia
Drone Enthusiast
when I get confused with situations like these I like to exaggerate the situation to try and figure it out in my head. So based on Robert's theory, if you took a 20' multirotor and held it up in the air, the triangle would give you the same proportional offset? Ah crap, this just made my brain hurt.
View attachment 2520
View attachment 2520
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I do that by hanging my hexa leg by leg with 2 axes
1° Horizontal
2° Vertical
Between each hanging a take a picture and after that with Paint I draw a ligne leg by leg.
Here 2 images with the horizontal situation.
After 2 lignes, you get de CG and it's easy to estimate mesure.
HA! get DJI to help? thats a good one. thats like asking Holger if he wants to do Lunch or asking Jeff from Xaircraft to call you back or getting a paid return from HobbyKing or expecting these things to fly out of the box.
Joking aside, it would be great to see a true way to determine this. Robert from DJI USA told me how but it really didn't make sense to me when I tried it out.
I do that by hanging my hexa leg by leg with 2 axes
1° Horizontal
2° Vertical
Between each hanging a take a picture and after that with Paint I draw a ligne leg by leg.
Here 2 images with the horizontal situation.
After 2 lignes, you get de CG and it's easy to estimate mesure.
Attachments
That is exactly how I did my Z axis. On my first set up I balanced it on the edge of a steel rule.
Now my esc's are strapped to the landing gear, so now if I make any major weight change I just check by balancing it on my finger tips.
For the return to home and land what should you have your receiver F/S set to on throttle? I thought I'd heard somwhere that it needs to be over 10% to avoid the motors shutting off so I've got ours at 50%. Not that we've tried it yet! The rate it backed the power off when it reached red voltage level once was scary enough!