Frequency-Response-Based Track-Following Controller Design for a Dual-Stage Actuator HDD Benchmark Problem Using a Sensitivity Decoupling Structure

This paper proposes a controller design method to improve track-following accuracy in a dual-stage actuator hard disk drive (HDD). The proposed approach employs a sensitivity decoupling structure and convex optimization based on the evaluation of the 𝐻2 norm using frequency response and disturbance data. Unlike conventional dual-stage actuator HDD design methods, which generate piezoelectric (PZT) actuator and voice coil motor (VCM) controllers with a common denominator, the proposed method independently tunes the denominators of the PZT and VCM controllers. In addition, constraints are introduced to ensure closed-loop stability in the presence of approximation errors in the decoupling filter. The effectiveness of the proposed method is demonstrated through time-domain response simulations using a dual-stage actuator HDD benchmark problem.