Robust H∞ control with regional stability constraints for the track-following systems of optical disk drives

This paper considers the problem of robust H_∞ control with regional stability constraints via error feedback for uncertain track-following systems of optical disk drives. A robust H_∞ control problem and the generalized Lyapunov theory are introduced for dealing with the problem. The error feedback H_∞ controller presented in this paper makes the tracking error settle within a tolerable limit and the control input not to be saturated. The regional stability constraints problem for uncertain systems can be reduced to the problem for the nominal systems by finding sufficient bounds of variations of the closed-loop poles due to modeling uncertainties. A controller design procedure is established using the Lagrange multiplier method. To evaluate the proposed controller design method, it is applied to the track-following system or a digital video disk recorder (DVDR)