Fixed-order dynamic compensation for linear systems with actuator amplitude and rate saturation constraints

In this paper we develop fixed-order (i.e. full- and reduced-order) controllers for continuous-time and discrete-time linear systems with actuator amplitude and rate saturation constraints. The problem is formulated as a multiobjective problem involving a convex combination of an L(1) norm and the H(2) norm to capture actuator saturation constraints and closed-loop system performance in the face of exogenous white noise disturbances. The L(1) convolution operator norm considered is induced by bounded amplitude persistent L(infinity) disturbances and L(infinity) performance variables involving the actuator amplitude and rate signals. Hence, the peak pointwise-in-time actuator amplitude and actuator rate excursion are guaranteed to be less than the product of the L(1) convolution operator norm and the L(infinity) disturbance amplitude bound. Application of the proposed framework to the design of multivariable saturation controllers for the control of a bank-to-turn missile and a high-performance fighter aircraft is demonstrated.