Adaptive resonant mode compensation for hard disk drives

Ohno, Ken; Hara, T.

doi:10.1109/tie.2006.870660

Cited by 48 publications

(14 citation statements)

References 5 publications

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“…In that method, the mechanical parameters of the arm are identified during the acceleration period and the identified parameters are used for the residual vibration suppression during the settling period (Iwasaki et al 1998). Ohno and Hara proposed the adaptive resonant mode identification method for Hard Disk Drives (Ohno and Hara 2006). The real-time identified controlled object model is described as follows:…”

Section: Adaptive Nonstationary Control Methodsmentioning

confidence: 99%

Adaptive nonstationary positioning control of vibration systems by means of solutions of time-varying Riccati equations

Hara

2006

Microsyst Technol

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The author's previous study proposed an efficient design method of time-varying gain type controller using the solutions of time-varying Riccati equations (TVREs) and its application to positioning control of time-invariant vibration systems. The responses of this method become similar to the responses of conventional nonstationary optimal regulators (NORs) which are effective controllers for positioning of vibration systems. This method generates the solutions of a TVRE and the responses of a controlled object simultaneously. The time-varying gains are obtained by real-time computations in actual implementations. This feature is convenient for the realization of some adaptive control. However, such a control method has not been fully addressed yet. This study proposes an adaptive nonstationary control (ANSC) method based on the feature of the previous study. We choose a cart with a time-varying vibration system whose natural frequency is time-varying as a controlled object example. The positioning and residual vibration reduction of the object are discussed in this paper. The effectiveness of the ANSC method is verified by simulations and experiments.

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Section: Adaptive Nonstationary Control Methodsmentioning

confidence: 99%

Adaptive nonstationary positioning control of vibration systems by means of solutions of time-varying Riccati equations

Hara

2006

Microsyst Technol

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“…An adaptive notch filter, comprising of a tunable finite-duration impulse response (FIR) filter and its tuner, was designed to identify the resonance frequency of the actuator rapidly and adjust its center frequency in an automatic manner [15]. A similar method, in which the center frequency follows the change in resonant frequency based on the balance of two types of frequency weighted variances of the control input signal, was used in [16]. Besides adaptive notch filters, indirect adaptive compensation (IAC), and structurally parallel compensation (SPC) were also proposed for resonant mode compensation in HDD dual stage actuation systems [17].…”

Section: Introductionmentioning

confidence: 99%

Discrete time adaptive controller for suppression of resonance in hard disk drive servo system

Rahman

Mamun

Yao

2015

Int. J. Control Autom. Syst.

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Mechanical resonant modes of the actuator severely impede the efforts in achieving high precision in head positioning servo system of hard disk drives (HDD). Hence it is important that these modes be properly compensated. The conventional approach is to use a notch filter in cascade with the nominal controller, which works well if the resonant frequencies are known and do not vary during operation. However, in reality, frequency and damping ratio of the resonant modes vary in mass-produced systems. They also get changed over time due to wear and tear. As a result, auto-tuning or adaptation of the notch filters is required to maintain the performance at the same level. In this paper, a discrete time adaptive controller is presented in a simple and yet efficient way to suppress the effects of resonant modes. Effectiveness of the proposed compensator is demonstrated through simulation and experiments by implementing the compensator for a Voice Coil Motor (VCM) actuator used in HDD.

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“…A tuner is designed to identify the resonance frequency rapidly, and the center frequency of the filter is adjusted automatically. A similar method is used in Ohno and Hara (2006), in which the center frequency follows the change in resonance frequency based on the balance of two types of frequency weighted variances of the control input signal. However, in almost all the adaptive methods, finding the adaptive law is nontrivial and choosing the adaptive law parameters is tedious.…”

Section: Introductionmentioning

confidence: 99%

Design and Implementation of Feedback Resonance Compensator in Hard Disk Drive Servo System: A Mixed Passivity, Negative-Imaginary and Small-Gain Approach in Discrete Time

Rahman

Mamun

Yao

et al. 2015

J Control Autom Electr Syst

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This paper presents a feedback resonance compensator designed in a simple and yet efficient way to suppress the effects of resonant modes of voice coil motor actuator used in hard disk drive (HDD) servo system. A velocity feedback controller is chosen as the feedback resonance compensator. Resonant modes of the actuator prohibit bandwidth to be pushed to higher frequencies and it causes large oscillations to the closed-loop system response. Therefore, effective compensation of mechanical resonant modes is one of the design challenges in HDD servomechanism. The proposed design is based on a mixed passivity, negative-imaginary and small-gain approach in discrete time which results in a robust stable controller. Firstly, stability of discrete-time interconnected system is analyzed using mixed passivity, negative-imaginary and small-gain properties. These results are analogous to previously established continuous-time case. Nowadays most of the control design is done in discrete time. Hence, this paper provides a base for discretization of mixed system with passivity, negativeimaginary and small-gain properties. Secondly, a velocity feedback controller for resonance compensation is designed using this mixed approach. Simulation and experimental results substantiate the effectiveness of the controller.

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Adaptive resonant mode compensation for hard disk drives

Cited by 48 publications

References 5 publications

Adaptive nonstationary positioning control of vibration systems by means of solutions of time-varying Riccati equations

Adaptive nonstationary positioning control of vibration systems by means of solutions of time-varying Riccati equations

Discrete time adaptive controller for suppression of resonance in hard disk drive servo system

Design and Implementation of Feedback Resonance Compensator in Hard Disk Drive Servo System: A Mixed Passivity, Negative-Imaginary and Small-Gain Approach in Discrete Time

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