An improved mixed H/sub 2//H/sub /spl infin// control design for hard disk drives

A data driven control design approach in the frequency domain is used to design track following feedback controllers for dual-stage hard disk drives using multiple data measurements. The advantage of the data driven approach over model based approach is that, in the former approach the controllers are directly designed from frequency responses of the plant, hence avoiding any model mismatch. The feedback controller is considered to have a Sensitivity Decoupling Structure. The data driven approach utilizes H∞ and H2 norms as the control objectives. The H∞ norm is used to shape the closed loop transfer functions and ensure closed loop stability. The H2 norm is used to constrain and/or minimize the variance of the relevant signals in time domain. The control objectives are posed as a locally convex optimization problem. Two design strategies for the dual-stage hard disk drive are presented.

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Application of MIMO Data Driven Feedback Control Design to Dual Stage Hard Disk Drives

Volume 1: Adaptive/Intelligent Sys. Control; Driver Assistance/Autonomous Tech.; Control Design Methods; Nonlinear Control; Robotics; Assistive/Rehabilitation Devices; Biomedical/Neural Systems; Building Energy Systems; Connected Vehicle Systems; Control/Estimation of Energy Systems; Control Apps.; Smart Buildings/Microgrids; Education; Human-Robot Systems; Soft Mechatronics/Robotic Components/Systems; Energy/Power Systems; Energy Storage; Estimation/Identification; Vehicle Efficiency/Emissions ◽

10.1115/dscc2020-3260 ◽

2020 ◽

Author(s):

Prateek Shah ◽

Zhi Chen ◽

Roberto Horowitz

Keyword(s):

Feedback Control ◽

Frequency Response ◽

Design Methodology ◽

Hard Disk Drives ◽

Control Design ◽

Hard Disk ◽

Data Driven ◽

Disk Drives ◽

Feedback Controllers ◽

Dual Stage

Abstract With increasing data density on hard disk drives, there is need to develop more robust and better performing track following control systems. We present a multi-input multi-output (MIMO) data driven feedback control design methodology. The design considers multiple frequency response measurements of all actuators, simultaneously, ensuring robustness of the control design system. A mixed H2 – H∞ norm locally convex optimization algorithm is used to synthesize the feedback controllers for MIMO systems. Feedback controllers are developed for dual stage hard disk drives using the MIMO data driven control design technique. A dual stage hard disk drive comprises of two actuators in series, controlling a read/write head onto a rotating disk. Our objective is to stabilize the closed loop of the actuators and minimize the error position signal of the read/write head. H2 norm and H∞ norm control objectives are used to formulate the MIMO data driven control problem. The design is based on a set of five frequency response measurements of the two actuators. We also compare the MIMO design methodology to a single-input multi-output (SIMO) design methodology presented earlier [1].

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