Switched nonlinear control of a VSTOL aircraft

A longitudinal model of a vectored-thrust Vertical and/or Short Take-Off and Landing (VSTOL) aircraft, which operates in three distinct modes, is a high-dimensional system whose performance can be enhanced with the use of switched nonlinear control. The aircraft's performance is limited by physical constraints on such parameters as ground speed, angle of attack, and thrust, which are summarized by the aerodynamic flight envelope. We specify a least-restrictive control law which will keep the aircraft within this envelope. We independently examine the aerodynamic flight envelope constraints and design the nonlinear controller for each mode using approximate feedback linearization, then combine the results to guarantee tracking within a "safe" envelope. We provide an example of switching between these modes in a short take-off maneuver based on pilot data.