Variable structure and nonlinear adaptive flight path control

Treats the question of inertial trajectory control of aircraft in the three-dimensional space. The control system is decomposed into a variable structure outer-loop and an adaptive inner-loop. The outer-loop feedback control system accomplishes (x, y, z) position trajectory and sideslip angle control using the derivative of thrust and three angular velocity components (p, q, r) as virtual control inputs. Then an adaptive inner feedback loop is designed, which produces the desired angular rotations of aircraft using aileron, elevator, and rudder control surfaces to complete the maneuver. These results are applied to a simplified FA-18 model. Simulation results are presented which show that in the closed-loop system asymptotic trajectory control is accomplished in spite of uncertainties in the model at different flight conditions.