$H_\infty$ Optimization With Pole Constraints of Static Output-Feedback Controllers—A Non-Smooth Optimization Approach

A non-smooth optimization approach for designing constant output-feedback controllers for linear time-invariant systems is considered. The design requirements combine H_∞ performance requirements with regional pole constraints. The pole constraints are embedded in the design criterion using a transformation on the system model which modifies the H_∞-norm of the closed-loop system via a barrier function that is related to the closed-loop poles damping. The method is applied to various flight control examples.