Nonlinear Controller With the Dead-Zone and Saturation for Optical Disk Drive Systems in the Presence of External Shocks

In this paper, a nonlinear controller with dead-zone and saturation is proposed in order to improve the antishock performance. Since using dead-zone and saturation improves the stability margin, we can use a higher gain for the dead-zone than in the previous methods. In addition, we find that the overall controller with a linear lead-lag controller has an improved stability margin over controllers with the PID linear control in this application. The experimental results confirmed that the proposed method provides improved protection against external shock.