Advanced Motion Control: An Industrial Perspective

Ind~~strial feedback motion controllers are hmed using inanual loopshaping, according to certain design r~des. This controller tuning serves as a benchmark for robust control research as applied to optical and magnetic disk drive storage systems. The design and implementation of robz~st controllers for the focus servo of a compact disk and the tmcking servo of a hard disk mechanism is investigated. The design objective is to achieve good track-following peg5ormance in rhe presence of disk disturbances. H, r o b ~ ~ s t control is used to systematically include disturbance and specijkatiorz models in the standard plant framework, The control design iteration is based on disturbance identijication, including implementation within the design cycle. The industrial relevance of robust control is discussed and areas for academic research in robust control are indicated, as feedback from industry.