Robust design of reduced order multirate compensators using constrained optimization techniques

The authors present an optimization based approach to the robust design of reduced order multirate compensators. An expanded linear quadratic Gaussian (LQG) cost function coupled with mixed frequency and time domain constraints is utilized in a constrained optimization framework to yield reduced order multirate compensators. The frequency domain constraints are associated with the singular values of the multirate system while the time domain constraints are employed to minimize excessive control effort or undesirable transient behavior often present in multirate systems