Efficient implementation of adaptive feedforward runout cancellation in a disk drive

This paper presents an improved adaptive feedforward compensation (AFC) technique for periodic disturbance cancellation. It has a better rate of convergence than AFC. It can also compensate for a particular harmonic without amplifying the adjacent uncompensated harmonics. A frequency domain design strategy is proposed. The results are verified both through simulations and by an experiment on a disk drive with a dedicated servo channel.