Two-Time-Scale Slow and Fast State Tracking of an F-16 Using Slow and Fast Controls
2017, American Institute of Aeronautics and Astronautics. All rights reserved. This paper extends the two-time-scale method of simultaneous slow and fast state tracking for a nonlinear six-degree-of-freedom aircraft to include throttle as a slow control in addition to elevator, aileron and rudder as fast controls. The control law is developed using a two-stage procedure that considers each control as the sum of two components designed over two different time-scales. The selection of closed-loop gains dictates the speed of response for each state under tracking, and maintains the time-scale separation between the slow and fast dynamics. The control law is implemented on a generic F-16 commanded to perform a large-amplitude combined longitudinal and lateral/directional maneuver. Results presented in the paper demonstrate that the approach allows using throttle as an automatic control to maintain velocity close to trim during the maneuver. The approach ensures that the commanded slow and fast states are tracked well, and that all other states and controls remain bounded for reasonable choices of the actuator dynamics.