Stability Analysis of a Missile Control System with a Dynamic Inversion Controller

Examines the closed-loop stability of a bank-to-turn, air-to-air missile with a dynamic inversion controller using a two time-scale separation assumption. A state-space formulation for the /spl alpha/, /spl beta/, and /spl phi/ dynamics of the missile, assuming the inner-loop dynamic inversion is performed exactly, is presented. It is then shown that, under certain assumptions, the exponential stability of the /spl alpha/, /spl beta/, and /spl phi/ dynamics about the commanded values can be guaranteed if the inner loop design frequency is large enough. An example calculation of the required inner-loop frequency to guarantee stability is done for a particular bank-to-turn missile. Finally, nonlinear six degree-of-freedom simulation results of a maneuver performed with the dynamic inversion controller are presented.