WKM Changing IMU direction

saidquad

Member
Hard to explain but I'll try. I have a X8. A gopro is mounted on front side (nose direction) facing forward and a Sony Nex on the back side, facing backward. What I like to do is to change the nose direction of the multi every time I want to use each of these cameras. So that when I record via gopro the flight direction (and the nose direction) is where the gopro is mounted and when I record via NEX the flight direction and the nose direction would be where the NEX is mounted. As of now the IMU and GPS are mounted on COG (for x,y coordinates) and the IMU arrow is pointing to where the gopro is mounted (nose of the aircraft by now). I wonder if it is possible to change the aircraft nose and direction of the flight to where the NEX is mounted simply by setting the IMU direction as backward in the assistant software and also change the GPS direction.
 

Carapau

Tek care, lambs ont road, MRF Moderator
The easiest way of achieving this is to set up the aircraft for one direction and then save the settings, then do it again for the other direction and then you simply load the file for the direction you wish to fly in. Of course you will have to physically turn the GPS puck by 180 degrees each time you want to change direction. To be honest it sounds like this is a very over complicated way of doing things and is likely to induce a user error. Why not simply have both cameras facing the same direction?
 

saidquad

Member
Thanks Carapau. Somehow this is the best way of placement of cameras for my particular use right now. Vulcan flat X8. 15'' props. batteries bellow center plate, electronics over the center plate. To avoid having props on the picture I have mounted cameras a little bit further from the center plate on each side to hold the balance. If I mount both cameras on one side I can not adjust the COG on the center of the aircraft as I prefer. From your post I understand that it is possible to change the IMU placement in the assistant software and subsequently the flight direction would change. Since every other parameters are the same (IMU and GPS distances from COG and gains and so on) It's a matter of one click every time I want to change the IMU direction and of course trying not to forget turning the GPS puck physically.
 


Carapau

Tek care, lambs ont road, MRF Moderator
It's a matter of one click every time I want to change the IMU direction

It will only be this if the IMU is dead central horizontally otherwise you will have to deal with your X, Y and Z directions too as you will have effectively swapped sides by switching direction.
 



eskil23

Wikipedia Photographer
The flight controller does not care how the remote is wired. If the pitch and roll are reversed the UAV will fly backwards just like if you pushed the pitch back instead of forward.
 

hexhome

Television Broadcast Engineer, SUSA operator
You may be correct, my opinion was based on experience with tail rotor gyros on helicopters. My assumption was that the Flight Controller would fight what it senses as an opposite input. It may be that DJI sensors are smarter than I thought.
 



saidquad

Member
It will only be this if the IMU is dead central horizontally otherwise you will have to deal with your X, Y and Z directions too as you will have effectively swapped sides by switching direction.
COG is dead center and IMU and GPS are located exactly on zero point of X and Y axis, I think this will work. I'll give it a try on friday.
 

saidquad

Member
I got the chance to try it today and.......flip!! changed gps puck direction and changed the IMU direction in assistant software calibrated compass and Boom!! the bird flipped as soon as the throttle was over %50. I don't know what is damaged yet beside 4 props and the landing gear and maybe tow or three motors. Hard lesson: IMU direction must be the same as what is defined in the assistant software. I don't know why but it is as it is. I had a pretty nice 20 minutes flight before changing the IMU direction in assistant software.
 

Carapau

Tek care, lambs ont road, MRF Moderator
Think I got it. You may have indeed flipped the IMU in the assistant however the motor numbers haven't changed so now front right motor is not number 1 it is number 3 etc.
 

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