Joint optimization of high-order error feedback and realization for roundoff noise minimization in state-estimate feedback controllers

Joint optimization of high-order error-feedback and state-space realization to minimize roundoff noise at the output of a closed-loop system with a state-estimate feedback controller subject to l₂-scaling constraints is investigated. The problem is converted into an unconstrained optimization problem by using linear-algebraic techniques. The unconstrained optimization problem at hand is then solved iteratively by employing an efficient quasi-Newton algorithm with closed-form formulas for key gradient evaluation. A numerical example is presented to illustrate the utility of the proposed technique.