Dynamic Modeling and Control of a Piezo-Electric Dual-Stage Tape Servo Actuator

2008 ◽  
Author(s):  
Uwe Boettcher ◽  
Bart Raeymaekers ◽  
Raymond A. de Callafon ◽  
Frank E. Talke
Keyword(s):  
Low Frequency ◽  
Voice Coil Motor ◽  
Step Response ◽  
Time Model ◽  
Modeling And Control ◽  
Micro Actuator ◽  
Single Output ◽  
Lateral Tape Motion ◽  
Dual Stage ◽  
Dual Stage Actuator

We have implemented the design of a dual-stage actuator tape head for enhanced reduction of lateral tape motion (LTM) disturbance. Our design consists of a conventional voice coil motor (VCM) and a micro-actuator for coarse and fine positioning, respectively. The micro-actuator, which is mounted on the VCM, uses a piezo crystal and allows following LTM up to the kHz regime, while the VCM follows low frequency LTM. Using step response measurements and a realization algorithm, we have created a multi-input discrete-time model of the dual-stage actuator. Based on the model, we designed and implemented a dual-stage controller, using a dual-input single-output approach based on a PQ method. The dual-stage controller controls the position of both actuators and enables an increased track-following bandwidth along with a control signal that is smaller in magnitude than that for a conventional single-stage tape head.

High-bandwidth controller design for dual-stage actuator system in hard disk drives

2022 ◽  
pp. 107754632110623
Author(s):  
Shota Yabui ◽  
Takenori Atsumi
Keyword(s):  
Controller Design ◽  
Hard Disk Drives ◽  
Voice Coil Motor ◽  
Hard Disk ◽  
Disk Drives ◽  
Positioning Accuracy ◽  
Micro Actuator ◽  
Dual Stage ◽  
Actuator System ◽  
Dual Stage Actuator

Large-capacity hard disk drives are important for the development of an information society. The capacities of hard disk drives depend on the positioning accuracy of magnetic heads, which read and write digital data, in disk-positioning control systems. Therefore, it is necessary to improve positioning accuracy to develop hard disk drives with large capacities. Hard disk drives employ dual-stage actuator systems to accurately control the magnetic heads. A dual-stage actuator system consists of a voice coil motor and micro-actuator. In micro-actuators, there is a trade-off between head-positioning accuracy and stroke limitation. In particular, in a conventional controller design, the micro-actuator is required to actuate such that it compensates for low-frequency vibration. To overcome this trade-off, this study proposes a high-bandwidth controller design for the micro-actuator in a dual-stage actuator system. The proposed method can reduce the required stroke of the micro-actuator by increasing the gain of the feedback controller of the voice coil motor at low frequencies. Although the voice coil motor control loop becomes unstable, the micro-actuator stabilizes the entire feedback loop at high frequencies. As a result, the control system improves the positioning accuracy compared to that achieved by conventional control methods, and the required micro-actuator stroke is reduced.

Optimal Sliding Mode Dual-Stage Actuator Control in Computer Disk Drives

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Seung-Hi Lee
Keyword(s):  
Discrete Time ◽  
Sliding Mode ◽  
Voice Coil Motor ◽  
Disk Drives ◽  
Flexible Mode ◽  
Control Scheme ◽  
Dual Stage ◽  
Actuator Control ◽  
Dual Stage Actuator ◽  
Computer Disk

This paper presents a discrete-time design of a dual-stage actuator control system with sliding mode for computer disk drives. A state estimator based discrete-time boundary layer sliding mode control scheme is developed for a dual-stage actuator, which consists of a voice coil motor and a microactuator. Considering dominant microactuator flexible mode dynamics and the interaction between the two actuators, an optimal sliding hyperplane is designed to maximize their cooperation so as to attain desired responses. An application example demonstrates the utility of the proposed sliding mode dual-stage actuator control scheme for track-seek in the microactuator range, settle, and track-follow.

Speed- and Range-based Filter Design for Dual-Stage Actuator Control

2021 ◽  
pp. 1-9
Author(s):  
James Peyton-Jones ◽  
Aleksandra Mitrovic ◽  
G. M. Clayton
Keyword(s):  
Filter Design ◽  
Low Frequency ◽  
Response Characteristics ◽  
Speed Range ◽  
Dual Stage ◽  
The Individual ◽  
Actuator Control ◽  
Different Characteristics ◽  
Dual Stage Actuator ◽  
First Time

Abstract Dual-stage actuators, which combine two actuators with different characteristics, have gained interest due to their large-range, high-resolution positioning capabilities. Control of such systems is challenging because it requires balancing the relative contributions of the individual actuators in terms of speed, range and precision. The most common approach is to allocate effort to the actuators based on frequency but this can lead to misallocation in the case of low-frequency short-range trajectories. In this paper, the problem of trajectory allocation in dual-stage actuator systems is addressed using a recently developed range-based filter. The theoretical basis of the range-based filter is rigorously derived for the first time and insights regarding its use, specifically its reinterpretation as a speed-based filter, and its range-frequency response characteristics are presented. The new analysis not only explains the behavior of the filter clearly, but it provides a more robust strategy for incorporating range constraints in filter design for different desired trajectories.

Integral Resonant Control for Suppression of Micro-Actuator Resonance in Dual Stage Actuator

2012 ◽  
Vol 48 (11) ◽  
pp. 4614-4617 ◽  
Author(s):  
Abdullah Al-Mamun ◽  
Ehsan Keikha ◽  
Charanjit Singh Bhatia ◽  
Tong Heng Lee
Keyword(s):  
Micro Actuator ◽  
Dual Stage ◽  
Dual Stage Actuator ◽  
Resonant Control

Identification of Resonance Frequencies in Dual-Stage Hard Disk Drives: A Practical Strategy

2017 ◽  
Author(s):  
Minghui Zheng ◽  
Shiying Zhou ◽  
Masayoshi Tomizuka
Keyword(s):  
Hard Disk Drives ◽  
Control Process ◽  
Voice Coil Motor ◽  
Hard Disk ◽  
Disk Drives ◽  
Single Output ◽  
Main Challenge ◽  
Practical Strategy ◽  
Resonance Frequencies ◽  
Dual Stage

In hard disk drives (HDDs), there exist multiple mechanical resonances whose central frequencies may shift due to the change of environmental conditions such as the temperature. Such slowly varying resonance frequencies, if not handled properly, may degrade the positioning accuracy and even result in the instability of the closed-loop HDD system. Therefore, it is important to identify these resonance frequencies efficiently without interrupting the reading/writing process in HDDs. One main challenge of the frequency identification in a dual-stage HDD lies in the fact that it is a double-input-single-output (DISO) system. The outputs of the voice coil motor (VCM) and the piezoelectric microactuator (PZT) are coupled together. This paper proposes a practical strategy to identify the resonance frequencies in both the VCM and the PZT without disabling the PZT control process. Bandpass filters are utilized to separate the overall position error signal (PES) into several frequency segments based on priorly-known frequency range for each resonance. Two standard parameter adaptation algorithms are studied and discussed. Simulation results validate the effectiveness of proposed identification strategy.

Measurement and Sources of Lateral Tape Motion: A Review

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Bart Raeymaekers ◽  
Frank E. Talke
Keyword(s):  
Magnetic Tape ◽  
Measurement Methods ◽  
Track Density ◽  
Tape Drive ◽  
Edge Contact ◽  
Lateral Tape Motion ◽  
Dual Stage ◽  
Tension Transients ◽  
Tape Edge ◽  
Dual Stage Actuator

The sources of lateral tape motion in a tape drive are reviewed. Currently used measurement methods and models for lateral tape motion are analyzed and compared. The effect of roller run-out, tape edge contact, and tape tension transients on lateral tape motion is discussed. A dual stage actuator tape head is investigated to improve track-following capability and increase the track density on a magnetic tape.

Sign in / Sign up

Export Citation Format

Share Document