Repeatable runout compensation for hard disk drives using adaptive feedforward cancellation

In this paper, new methods to estimate repeatable runout (RRO) in hard disk drives are proposed. The techniques are based on adaptive feedforward compensation (AFC). To enhance the performance, two modifications (residual error shaping and Kalman filtering) are introduced to the basic AFC structure. The estimated data are used in real-time control to generate the compensation signal which cancels RRO disturbance. Simulation results show the effectiveness of the proposed schemes and the resulting improvement of tracking performance.