ROBUST FLIGHT CONTROL-SYSTEMS - A PARAMETER SPACE DESIGN

This paper deals with the longitudinal dynamics stabilization. around a trim condition, of an aircraft with unsatisfactory longitudinal stability characteristics. This problem is a single-input control problem because only elevator and canards deflections are used as control inputs, and they are simultaneously driven by the same control signal. To this aim, a new linear parameterization of all compensators stabilizing a given single-input plant is proposed, along with a design method based on a computationally tractable procedure for the robust stability analysis of polynomials with affinely dependent coefficient perturbations. Since scale factor sensor changes are perturbations entering affinely the characteristic polynomials coefficients of the closed-loop system, a controller will be synthesized in order to guarantee that the closed-loop poles lie in a specified domain of the complex plane prescribed by MIL specifications, and to achieve robustness against scale factor sensor failures. An application of the proposed procedure to the F4-E military aircraft is presented.