Input/output conditioning of robust integrated flight and propulsion controller

We describe the application of a conditioning scheme to a linear integrated flight and propulsion control system for an experimental vertical/short takeoff and landing aircraft configuration in the transition (approach to hover) region of the flight envelope is presented. The proposed scheme guarantees satisfaction of limits on safety critical engine variables by using output conditioning to back off pilot demands in the event of a limit being encountered. Bounded-input/bounded-output stability results are presented for the resulting closed-loop system. At the plant input, an actuator linearization scheme is designed to minimize performance degradation due to backlash dynamics in the aircraft's thrust vectoring nozzles. The conditioning scheme also provides a mechanism for explicitly prioritizing requirements on flight-path angle over velocity in the case of engine performance limitations being reached. Performance and safety improvements due to the addition of the controller conditioning scheme are demonstrated in nonlinear simulation.