In this paper, a new robust linear decentralized controller is proposed to enhance the transient stability of nonlinear multimachine power systems. Only local measurements are required in controller. The feedback gain each generator obtained by solving an algebraic Riccati equation based on bounds machine parameters. analysis shows that can guarantee system over whole operating region and regardless fault locations or parameter uncertainties transmission network. Compared with controllers,...

Ever-decreasing track width to nanometer level becomes a great challenge for servo systems fulfill short-span seeking and track-following in hard-disk drives (HDDs). This paper utilizes the reset integral-derivative element (RIDE), an controller whose states are set zero when its input is zero, both single- dual-stage HDD systems. The RIDE can reduce overshoot of step response, which will speed up operation. Furthermore, capability suppress output disturbances also found be improved....

In this brief, we propose a new mixed H/sub 2//H/sub /spl infin// control design via linear matrix inequality (LMI) based approach. By an equivalent transformation of Lyapunov inequality, additional slack variables are introduced to characterize both the 2/ and performances. Based on characterization, is proposed where add in degree freedom optimizing performance, resulting equal or better performance than existing LMI methods. The algorithm applied for hard disk drives (HDDs) problem...

This paper proposes a modified decoupled master-slave (DMS) dual-stage control scheme for hard disk drives that offers enhanced stability when the secondary-stage actuator is saturated. A nonlinear model used instead of linear in controller. modification allows microactuators with relatively smaller displacement range to be servo system without causing problems DMS Simulation and experimental results confirm effectiveness robustness scheme.

We show in this paper that the disk vertical vibration signal picked from slider a hard drive has fairly good correlation to track misregistration at flutter frequencies. propose introduce feedforward controller into usual servo loop reduce disk-flutter-induced (TMR). The is an approximated differential element with direction velocity as input. In our experimental setup, we such method can TMR induced by first four modes average of about 56%. potentially be used high-track-per-inch writers...

This paper applies the modified adaptive feedforward compensation (AFC) scheme to dual stage servo system for cancellation of repeatable runout (RRO) and nonrepeatable (NRRO). It shows that can be effectively compensated or attenuated by assigning components VCM actuator microactuator properly.

This brief gives a practical account of the application an improved adaptive neural network (NN) controller to voice-coil-motor (VCM)-actuator hard disk drive (HDD). Necessary modifications are presented which allow implementation for VCM-actuator with high-frequency resonances. For resonance compensation, notch filter compensators augmented while parameter estimation errors counteracted by employing robust techniques. It is shown practically that this good candidate track seek/following in HDDs.

Conventional servo track writing needs external devices to position heads in hard disk drives write patterns. In self-servo (SSTW), the reference is regenerated from previous written tracks and a pattern propagated cover progressive mode. Errors will propagate compound this process. paper, radial error propagation discussed containment scheme established. Furthermore, experimental results of SSTW on head-disk assembly with blank media off-the-shelf electronics are analyzed show effectiveness...

This paper proposes an optimization based control scheme for a dual-stage hard disk drive servo system to maximize the tracking accuracy given actuator bandwidth limitations without knowing mechanical disturbance model. We proposed add outer loop, selected on of Youla parameters, usual controller improvement. The parameters are bounded specifications minimum bandwidth, phase margin, and gain maximum limitations. Time domain frequency simulations were performed show effectiveness design. with...

This paper proposes a dynamic nonlinear control scheme to improve the seek-settling performance in hard disk drive servo system by combination of novel designed reference generator and feedback controller. The controller consists linear one for short rise time an associated small overshoot. In order settling stability due actuator saturation, trajectory is based on loop so that position error signal tracking stage decreased greatly, which effectively avoids saturation with high gain design....

This paper investigates the disturbance rejection problem for a data storage servo system that contains microactuator high-accuracy positioning. For disturbances with known frequencies, their is accomplished via generalized Kalman-Yakubovic-Popov lemma together Youla parameterization approach, and linear controller computed solving number of matrix inequalities. To further improve low-frequency such as nonlinear arising from friction torque or bias other unknown disturbances, an adaptive...

Currently, position sensors other than the read/write head are not embedded into current hard disk drives (HDDs) due to signal-to-noise ratio and nanometer resolution issues. Moreover, a noncollocated sensor fusion creates nonminimum phase zero dynamics which degrades tracking performance. In this paper, singular perturbation theory is applied decompose voice coil motor's (VCM's) induced PZT active suspension's fast slow subsystems, respectively. The control system decomposed time scales for...

A reset disturbance compensation scheme is developed to reject midfrequency narrowband disturbances, with an application the hard disk drives (HDDs). Generally, at band not effective through feedback control based on internal-model principle or high gain due phase stability. This paper investigates a and its favorable approximate frequency response using describing function. The makes gain-phase break fundamental Bode's constraint of linear time-invariant system provides maximal lead desired...

A servo track writing (STW) platform with dual piezoelectric (PZT) microactuator is proposed for higher density hard disk drives (HDDs). We mainly deal the control issues to achieve high density. Vibration and noise analysis based on measured position error signal (PES) indicates that PES significantly disturbed by narrow-band vibrations. Hence, we propose a general second-order phase lead peak filter (PLPF) applicable reject disturbances at all frequency ranges. The zero designed minimally...

This brief is concerned with servo loop design in the discrete-time domain that aims to achieve a low-hump sensitivity function for dual-stage hard disk drive (HDD) systems. Sensitivity functions systems are analyzed on basis of Bode integral theorem. A 3-dB hump achieved simulation actuation system piezoelectric (PZT) microactuator (MA) using H/sub /spl infin// shaping method and proposed linear matrix inequality (LMI) approach. Additionally, implementation done PZT MA magnitude lower than...

The dual-actuator hard disk drive with two voice coil motor actuators mounted in the diagonal corners of baseplate allows faster data access relatively slow spindle speed. However, mechanical interaction between tends to affect head positioning accuracy. In this paper, we use circle-fit modal testing method identify dual-input dual-output frequency response model plant. We discuss decentralized control scheme for tracking servo. servo loop decomposition reveals that induces narrow-band...