Call for VTOL test pilots! The PX4 standard firmware (master branch, downloadable via QGroundControl) supports first VTOL vehicle (duo-rotor, tail sitter). This video demonstrates the transition from hover - fixed wing - hover. Contact: http://px4.io/vtol.
Additional vehicles are currently in testing, including a BirdsEyeView FireFly Y6 (tilt rotor) and a Quadshot (quad tail sitter). The main benefit during initial bring-up of VTOL support of the TBS Caipirinha is its small size and high operational safety, combined with the inherent ruggedness of a flying wing airframe.
As the PX4 flight stack (running with the PX4 middleware on Pixhawk) is unified platform without separate multicopter or plane codebases and using the same command & control (arming, logging, safety) state machines and mission management for all platforms, its perfectly suited for VTOL development. Adding VTOLs didn't mean to introduce a new vehicle category, rather, it mostly meant adding a new mixer, a VTOL transition controller and some minor tweaks.
Note these are initial results leveraging existing multicopter and fixed wing controllers spiced with a VTOL transition controller - the dev team is meanwhile experimenting with model predictive controllers. But even this initial baseline implementation works quite well and is ready for some flying.
Comments
Hi Brandon,
Many people have shown the control approach, some I'm sure there are tons of videos out there. The current controller is nothing special compared to what is used in academia, but more advanced than what is used often in the community in that its a trust-vector based design instead of using any sort of angle representation. Also means the thing (and our quads) can do full 360's or inverted flight without any special case logic.
This will be replaced eventually with a model predictive controller to factor in the 3D motion constraints the airfoil induces - which in turn should allow the vehicle whatever configuration fits the desired trajectory best without putting it into a specific "control mode" first.
Awesome. It reminds me of this solution from a few years ago...
https://www.youtube.com/watch?v=T2lUJk-fziE
Do you guys have any papers on the control scheme?
You probably found the link already, but the build / setup log for anyone interested is here:
https://pixhawk.org/platforms/vtol/tbs_caipirinha_vtol
I'm gonna build me one. My small backyard had been restricting my flightoperations for way too long :-)
Very nice to see this development.
I'd like to participate in this, will apply.