Mixed H/H8 Method Suitable for Gain Scheduled Aircraft Control

The formulations of mixed H2/H1 gain scheduling control of aircraft in longitudinal motion aredeveloped. The coefe cients of a linear model of aircraft are estimated from the aircraft geometry. Based on e ight Mach number, gain scheduling is applied with the mixed H2/H1 . It is shown that the state equation of aircraft can be mathematically simplie ed to the standard mixed H2/H1 problem. The advantage of decoupling the aircraft system based on phugoid (slow) and short period (fast) modes is to allow the slow model with its disturbance to be controlled by the H2 method, whereas the fast system with the fast disturbance is to be stabilized by the H1 technique. A comparison of this method with the standard H1 control is made using aircraft coefe cients derived for a large commercial airplane. It is shown that the current method will provide better performance for the given aircraft while the condition on the disturbance attenuation is also satise ed. The actual model controlled by the estimated controller and by the real controller is also discussed. It is shown that the estimated controller performs as well as the controller derived from the actual model.