  In this paper, we present a frequency domain data-driven feedback control
design methodology for the design of tracking controllers for hard disk drives
with two-stage actuator as a part of the open invited track 'Benchmark Problem
on Control System Design of Hard Disk Drive with a Dual-Stage Actuator' in the
IFAC World Congress 2023 (Yokohoma, Japan). The benchmark models are Compared
to the traditional controller design, we improve robustness and avoid model
mismatch by using multiple frequency response plant measurements directly
instead of plant models. Disturbance rejection and corresponding error
minimization is posed as an H2 norm minimization problem with H infinity and H2
norm constraints. H infinity norm constraints are used to shape the closed loop
transfer functions and ensure closed loop stability and H2 norm constraints are
used to constrain and/or minimize the variance of relevant.
