A Practical Loop Shaping Design Procedure with Classical Control Criteria and Its Application to Hard Disk Drives

Abstract This paper is concerned with integration of classical control criteria into the H ∞ robust control design with the use of the H Infin; Loop Shaping Design Procedure (LSDP) by McFarlane and Glover. Classical control criteria such as gain crossover frequency and phase margin still play important roles to designing and evaluating feedback control systems in practical applications including Hard Disk Drives (HDDs) where empirical knowledge has great importance. The systematic use of the robust control design has been tried in industry. However, it has yet to be fully adopted simply because of the familiarity with the classical control criteria. In this paper, we will propose a way to design digital robust control systems with the use of the LSDP in which we can specify the classical control criteria. Application to HDDs will be demonstrated with a set of simulations to validate the proposed method.