I have finally tried building and flying a dual axis FPV gimbal, with camera pitch and roll being dynamically controlled via a head tracking gimbal. I wanted to know if this would be possible to fly in acro, how difficult it would be to learn, and if it would be practical.
I want to briefly discuss what I view as the biggest limitation of traditional cinematic FPV drones, which is that any movement of the camera pitch or roll relates to a change in the drones flight path and likewise any change to flight path relates to a change in the cameras pitch or roll, yaw is an exception to this. When I first began thinking of head tracking gimbals my vision was of a dual axis FPV gimbal, but I first tested a single axis (pitch) and realized it alone was a game changer and significantly augmented a FPV drone’s capabilities, while the second axis, roll, is more for camera correction than anything else, as you gain nothing that helps pilot the drone from rolling the camera.
Adding an additional axis to the gimbal for roll could potentially solve the remaining limitation of a single axis FPV gimbal, which is that roll is directly connected with the roll of the drone itself resulting in ‘dutch angle’ in some types of shots, in particular those related to chasing moving objects at high speeds.
My first flights were interesting, I was pleasantly surprised to find that it wasn’t difficult to fly it like it was a single-axis gimbal and unless I was intentionally manipulating the roll axis I didn’t notice much difference. I also used some ‘expo’ on the gimbal’s roll channel to let the center be easier to find, some dead-band in the center would also work for that. However.. actually using the roll axis to correct ‘dutch angle’ proved to be tricky, I was flying in my yard so the only way I could get dutch angle to correct is via orbiting various things. I was again pleasantly surprised when I actually did pull off correcting the camera roll via the head tracker in an orbit, however coming out of the orbit and getting my head back centered was very difficult. Basically I need to learn to cross-coordinate the drone and gimbal movement with roll the same way I have learned to do with pitch, which should be possible with enough practice, which I intend to continue to do, at least occasionally.
Is this practical?… I am unsure, a single axis definitely is and is the next step for cinematic FPV, but dual axis really only serves to solve a camera correction issue that is only prevalent in certain scenarios. Cinewhoops only need a single axis, in my opinion, as you don’t deal with big ‘dutch angles’ often when filming with them. Considering how much more difficult it is to learn I am not sure it is practical even for chasing, but it certainly ‘could’ be the ultimately chase drone. Maybe after a few months of flying with it it will become as natural as the single-axis is to me now, maybe it won’t. I will update this as I do more flying/tuning with it.
Files on Thingiverse: https://www.thingiverse.com/thing:5078910