A REDUCED ORDER CONTROLLER DESIGN METHOD BASED ON THE YOULA PARAMETERIZATION OF ALL STABILIZING CONTROLLERS

摘要

Two issues, those of reduced order controller design and computational algorithms, have been given shorter shrift than they deserve; for, if a controller design method is to be considered useful to practitioners, it must yield controllers that can be implemented in hardware and/or software and it must be possible to reliably calculate such controllers. Previous results by others have indicated how the arbitrary parameters of the Youla parameterization can be manipulated to directly yield reduced order controllers; however, no realistic algorithms have been offered. This paper presents a step towards such practical algorithms. Specifically, an efficient and arguably stable algorithm for calculating controllers of order min{v_0 - l,v_c - l} that also achieve arbitrary placement of closed loop poles is presented. Additional applications of the algorithm to iterative design and H~8 design are indicated.