Track following control using nonlinear model predictive control in hard disk drives

In this paper, a Nonlinear Model Predictive Control (NMPC) is proposed to control a single stage Voice-Coil-Motor (VCM) of a Hard-Disk-Drive (HDD). Due to its fast settling time and its robustness, this controller is suggested to be applied for the first time to control a R/W head of an HDD. To highlight the good performance and characteristics of the NMPC, a comparative study with a standard PID control is presented. The two control methodologies were evaluated in nominal conditions as well as in other situations such as disturbances and uncertainties on the plant model parameters. In all cases, NMPC presents much better simulation results in term of speed and robustness in the presence of unexpected perturbations and parameters' change.