Active Vibration Rejection in Multi Actuator Drives: Data Driven Approach

Abstract

Multi Actuator Technology was unveiled in December 2017 by Seagate, a breakthrough that can double the data performance of the future generation hard disk drives. This technology will equip drives with dual actuators operating on the same pivot point. Each actuator will control half of the drives arms. This new technology brings new control challenges with it. Since two actuators operate independently on the same pivot timber, the control forces and torques generated by one actuator can affect the operation of the other actuator. The independent functioning of the two actuators will lead to a scenario of one actuator in the track seeking mode while the other actuator is in the track following mode. It is expected that the track seeking actuator will impart vibration onto the track following actuator, worsening its performance drastically. In this paper, we propose a methodology to estimate this imparted vibration and to design feedforward controllers for the voice coil motor and the micro actuator, of the track following actuator, to suppress the estimated vibration. The vibration estimation is performed using power spectral factorization techniques. Whereas, the feedforward controllers are designed using a mixed H2 – H∞ data driven methodology to obtain a robust design.