Optimal finite wordlength digital controller realization

Summary form only given. We present an algorithm based on the metrics previously proposed by the authors (1994) for computing optimal controller implementation structures under finite wordlength (FWL) constraints. The FWL robustness measure is based on the complex stability radius. Even though this measure is potentially conservative, it rigorously guarantees closed-loop stability and for this reason is preferred over other measures such as pole-sensitivity. Using a series of equivalences we show that the optimal controller coordinate transformation matrix T can be obtained by solving an optimization problem. We also discuss optimal realizations from the point of view of minimizing the degradation in closed-loop H^∞ performance