Multivariable control design for the control reconfigurable combat aircraft (CRCA)

Multivariable output feedback digital control laws are designed for the control reconfigurable combat aircraft (CRCA). The design incorporates the high-gain error-actuated proportional plus integral (PI) controller. Control law development and simulation are performed using the computer aided design program called MATRIX_x. The CRCA design includes an all-flying canard with 30° of dihedral angle which prevents the normal separation of lateral and longitudinal equations because of high aerodynamic cross-coupling. Consequently, developing a satisfactory controller for all aircraft motion must include all of the control surfaces. The three control surfaces on each wing are operated together; so they are treated as one control effector. Thus, the five CRCA control inputs for this design consist of two canards, left trailing edge flaperon, right trailing edge flaperon, and rudder. The aircraft dynamics are linearized about three flight conditions ranging from high speed and low altitude, to high speed and high altitude. Fixed-gain PI controllers are designed at each flight condition for both the healthy aircraft and with a failed left canard and left trailing edge flaperon. Decoupling of the output variables is achieved and demonstrated by two maneuvers. Simulation indicates that the controller is very robust and output responses are fully satisfactory