USE OF OPTIMAL INTEGRAL CONTROL TO RESTORE TRIM IN A RECONFIGURABLE FLIGHT CONTROL SYSTEM

Abstract

Description of State-of-the-Art Features. In a reconfigurable flight control system actuator or control surface failures are detected from output signals obtained from the system's motion sensors. When such a failure occurs the control law of the flight control system is reconfigured in a manner that results in the aircraft retaining an acceptable degree of control and handling. The reconfiguration is achieved by arranging for the new control law to use, sometimes in a manner different from custom, all the other appropriate serviceable actuators and control surfaces. In practice, such reconfiguration schemes have greater effectiveness when used in aircraft which possess much greater control freedom than is usually found in conventional aircraft. On fighter aircraft there are generally more control surfaces with a capacity to act independently, differentially, or collectively. The motion of such types of aircraft may be coupled quite strongly so that the loss of a single control can have significant effects on the resulting closed-loop motion. In this paper the proposed reconfiguration system is developed for a generic fighter aircraft with eight control surfaces and whose lateral and longitudinal motion is to be controlled simultaneously.