An RC VTOL plane all the time makes for a compelling challenge, however making certain the transition between hover and ahead flight might be fairly difficult. Within the video after the break, [Nicholas Rehm] demystifies of the flight management algorithm required for a VTOL tailsitter.
Tailsitters are one of many easiest VTOL preparations, the testbed right here being a easy foam KF airfoil wing with two motors and two servo-controlled elevons. As with virtually all his tasks [Nicholas], makes use of of his open-source dRehmFlight flight controller to exhibit the sensible implementation of the management algorithm.
Three main elements that have to be concurrently taken into consideration when transitioning a tailsitter VTOL. First off, yaw turns into roll, and vice versa. This means that in hover mode, elevons have to maneuver in reverse instructions to manage yaw; nevertheless, this similar motion will make it roll in ahead flight. The identical applies for differential thrust from motors — it controls roll in hover and yaw in ahead flight. Nonetheless, this transformation of management scheme solely works if the flight controller additionally alters its reference body for “stage” flight (i.e., flips ahead 90°). As [Nicholas] demonstrates, failing to take action leads to a fast and chaotic encounter with the bottom.
With these changes made, the plane can transition to ahead flight however will oscillate pitch-wise because it overcorrects whereas attempting to take care of secure flight; this is because of PID beneficial properties – third issue. The deflection required by management surfaces is rather more aggressive throughout hover mode; thus PID beneficial properties have to be lowered throughout ahead flight. A remaining enchancment entails including a quick delay when switching modes for smoother rotation.
For extra attention-grabbing VTOL configurations, try [Tom Stanton]’s RC V-22 Osprey, and this photo voltaic recharging trimotor
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