VTOL (vertical take-off and touchdown) solves an enormous downside for plane design and flight dynamics. A standard fixed-wing airplane requires an extended runway, as a result of it has to succeed in a adequate pace earlier than it begins producing carry. A helicopter would not want a runway in any respect, however its flight is gradual and inefficient in comparison with the airplane. A VTOL plane, just like the well-known V-22 Osprey or Harrier bounce jet, offers the very best of each worlds. However whereas these designs make lots of sense for manned plane, Nicholas Rehm’s drone takes a singular method to VTOL that’s extra appropriate for unmanned plane.
Tilt-rotor plane, together with the Osprey, work by taking off with their rotors dealing with upwards. Then once they’re within the air, these rotors transition to face forwards for regular flight. That’s preferrred, as a result of it maintain the physique (and passengers) stage. Nevertheless it requires actuation to tilt the rotors between positions and that added complexity is not obligatory for an unmanned plane like a drone. As an alternative, as Rehm demonstrates, all the plane can change orientation.
It is a “tailsitter” design and the identify comes from the way in which the plane sits on its tail earlier than it takes off. There have been many prototype designs for manned tailsitter plane over the past century, however they’re all the time deserted as a result of piloting them throughout VTOL is tough. That is not a problem for a drone and so Rehm constructed this prototype tailsitter to work out the practicalities of the transition between VTOL and regular flight.
Rehm’s tailsitter makes use of the identical components you’d see on any hobbyist drone or airplane. To keep up steady flight, the flight controller consistently screens the drone’s orientation utilizing an IMU (Inertial Measurement Unit) and gyroscope module. However as a result of that orientation is meant to alter with a tailsitter design, Rehm needed to develop some customized code.
Rehm’s code does just a few vital issues. First, it swaps the incoming roll and yaw instructions when the pilot flips a change. That is obligatory as a result of the axes orientation modifications between flight modes, which might be tough for the pilot to account for manually. Second, it tells the flight controller to alter the “vertical” axis between modes so the soundness algorithms maintain working to keep up stage flight.
The cool factor about this method is that it lets the drone routinely change between VTOL and regular flight. When Rehm flips the toggle, the flight controller routinely adjusts the plane to realize the brand new stage. However that occurs immediately, which is a bit of jarring. To ease the transition, Rehm applied some “fade” code. That slowly adjusts the vertical axis worth over a few seconds, so the flight controller easily reorients the drone.
This works very effectively, however this drone is only a prototype. Rehm plans to make use of the teachings he realized to construct a extra polished plane quickly.