Control relevant identification of a compact disc pick-up mechanism

This paper discusses the control relevant parametric identification of a servo system present in a Compact Disc player. In this application an approximate closed loop identification problem is solved in order to come up with a linear multivariable discrete time model, suitable for control design. This identification problem is handled by a recently introduced two stage method. It yields an explicit and tunable expression for the bias distribution of the model being estimated, clearly showing the dynamics of the closed loop system in the (asymptotic) approximation criterion. This result will be exploited to identify the model in a control relevant way by additional data filtering. The recently introduced method in de Vries and Van den Hof (1993) for model uncertainty quantification is used to construct an upper bound for the corresponding model error.