MIMO sliding mode control as an alternative to reconfigurable flight control designs

Sliding mode control is applied to the design of flight control systems capable of operating with limited bandwidth actuators and in the presence of significant damage to the airframe and/or control effector actuators. The selection of the sliding manifold as well as the interpretation of the resulting linear design is accomplished in the frequency domain. The well-documented sensitivity of sliding mode controllers to parasitic dynamics is addressed through the use of asymptotic observers and reference model "hedging" also designed in the frequency domain. The design technique is exercised on a multi-input, multioutput lateral-directional controller for a simple model of the NASA High Angle of Attack Research Vehicle via computer simulation. The performance of the sliding mode design is compared with that of two competing design approaches.