Experimental validation and ℋ∞ control of the opto-mechanical coupling effect in DVD servo-mechanisms

This paper deals with the experimental validation and the corresponding robust control of the opto-mechanical coupling effect in new generations of optical disk drives. While in many industrial control implementations, the radial and focus loops are considered as decoupled (e.g. DVD format), this is no longer true for HD-DVD and Blu-ray disc (BD) formats which are sensitive to opto-mechanical interactions. The impact of such phenomena on the performance of the servo is here evaluated by using experimental data, and a ℋ_∞ controller is designed to reduce the coupling effect, by using a suitable disturbance model into the problem formulation. Simulations using experimental data illustrate the performance improvement of the compensated system.