Triple-Stage Track-Following Servo Design for Hard Disk Drives

2016 ◽  
Author(s):  
Jinwen Pan ◽  
Omid Bagherieh ◽  
Behrooz Shahsavari ◽  
Roberto Horowitz
Keyword(s):  
Controller Design ◽  
System Modeling ◽  
Hard Disk Drives ◽  
Low Frequency ◽  
Stability Margin ◽  
Disturbance Attenuation ◽  
Stability Margins ◽  
Control Objective ◽  
Robust Control Design ◽  
Actuation Systems

This paper studies possible robust control design methods in triple-stage actuation settings for achieving minimum position error signal (PES) while maintaining enough stability margins. Firstly, the sensitivity-decoupling design technique, is utilized to estimate the resulting increase in low frequency disturbance attenuation and servo bandwidth. A systematic tuning methodology based on μ-synthesis is then proposed for track-following servo design of triple-stage actuation systems. In this approach, the objective is to minimize the PES, by considering all constraints and uncertainties explicitly in the design. We describe a step by step Multi-Input Single-Output (MISO) controller design methodology which includes system modeling, noise characterization, control objective determination and controller synthesis and verification. In this methodology, servo bandwidth is not the only performance metric. Rather, the control objective will be to minimize the closed-loop system H∞ norm directly, while all stroke and control constraints are satisfied and enough stability margin is ensured. The proposed method is applied to design track-following feedback controllers for single-, dual- and triple-stage actuation systems. Simulation results show that compared to dual-stage actuation, triple-stage actuation enhances low frequency disturbance rejection by 6 dB at around 100Hz and increases servo bandwidth from ∼3kHz to ∼5kHz.

In-Circuit Characterization of Low-Frequency Stability Margins in Power Amplifiers

2019 ◽  
Vol 67 (2) ◽  
pp. 822-833
Author(s):  
Jose Manuel Gonzalez ◽  
Nerea Otegi ◽  
Aitziber Anakabe ◽  
Libe Mori ◽  
Asier Barcenilla ◽  
...  
Keyword(s):  
Power Amplifiers ◽  
Low Frequency ◽  
Frequency Stability ◽  
Stability Margins

Settling Control of the Triple-Stage Hard Disk Drives Using Robust Output Feedback Model Predictive Control

2016 ◽  
Author(s):  
Huy Nguyen ◽  
Omid Bagherieh ◽  
Roberto Horowitz
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Output Feedback ◽  
Frequency Control ◽  
Hard Disk Drives ◽  
Low Frequency ◽  
Hard Disk ◽  
Control Input ◽  
Feedback Model ◽  
Actuator Constraints

Track settling control for a hard disk drive with three actuators has been considered. The objective is to settle the read/write head on a specific track by following the minimum jerk trajectory. Robust output feedback model predictive control methodology has been utilized for the control design which can satisfy actuator constraints in the presence of noises and disturbances in the system. The controller is designed based on a low order model of the system and has been applied to a higher order plant in order to consider the model mismatch at high frequencies. Since the settling control generally requires a relatively low frequency control input, simulation result shows that the head can be settled on the desired track with 10 percent of track pitch accuracy while satisfying actuator constraints.

scholarly journals New Reconfiguration Technique for Ultracapacitor for Exchange of Energy At A Faster Rate

2019 ◽  
Vol 9 (1) ◽  
pp. 1684-1689
Keyword(s):  
Dynamic Load ◽  
Hybrid Electric Vehicle ◽  
Hardware Implementation ◽  
Controller Design ◽  
System Modeling ◽  
Voltage Regulation ◽  
Maximum Energy ◽  
Energy Economy ◽  
Energy Sharing ◽  
Maximum Utilization

This paper deals with the use of the maximum energy of ultracapacitor at a faster transaction rate. This paperalso deals with the system-modeling, controller design, and faster energy transaction from ultracapacitor bank used in a hybrid electric vehicle. The energy transaction to dynamic load is through parallel-connected ultracapacitor bank and battery combination. The parallel-series topology has been implementing for ultracapacitor and the controller is designed to control energy-transactions from ultracapacitors. The DC-DC converter is only used for voltage regulation. This topology has aimed at the design leading to the excellent energy economy. Further, the main objective is to attain maximum utilization of energy in ultracapacitors during a ride-through condition, in minimum time. Three simulations have been carrying out with hardware implementation to compare these results. This includes energy sharing by ultracapacitor, in case of dynamic load. Hence, the proposed control strategy can provide a satisfactory improvement in energy- efficiency of ultra-capacitors, assuring maximum utilization and faster energy transaction.

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.

A New Iterative Identification and Control Method of Closed-Loop Power System Based on Ambient Signals

2015 ◽  
Vol 798 ◽  
pp. 261-265
Author(s):  
Miao Yu ◽  
Chao Lu
Keyword(s):  
Power System ◽  
Closed Loop ◽  
Control Method ◽  
Controller Design ◽  
Design Method ◽  
Stability Margin ◽  
System Stability ◽  
Iterative Identification ◽  
Effective Performance ◽  
And Control

Identification and control are important problems of power system based on ambient signals. In order to avoid the model error influence of the controller design, a new iterative identification and control method is proposed in this paper. This method can solve model set and controller design of closed-loop power system. First, an uncertain model of power system is established. Then, according to the stability margin of power system, stability theorem is put forward. And then controller design method and the whole algorithm procedure are given. Simulation results show the effective performance of the proposed method based on the four-machine-two-region system.

scholarly journals A Novel Piecewise Frequency Control Strategy Based on Fractional-Order Filter for Coordinating Vibration Isolation and Positioning of Supporting System

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5307
Author(s):  
Yeying Tao ◽  
Wei Jiang ◽  
Bin Han ◽  
Xiaoqing Li ◽  
Ying Luo ◽  
...  
Keyword(s):  
Fractional Order ◽  
Control Strategy ◽  
Vibration Isolation ◽  
Frequency Control ◽  
Low Frequency ◽  
Stability Margin ◽  
System Stability ◽  
Supporting System ◽  
Frequency Position ◽  
The Stability

A piecewise frequency control (PFC) strategy is proposed in this paper for coordinating vibration isolation and positioning of supporting systems under complex disturbance conditions, such as direct and external disturbances. This control strategy is applied in an active-passive parallel supporting system, where relative positioning feedback for positioning and absolute velocity feedback for active vibration isolation. The analysis of vibration and deformation transmissibility shows that vibration control increases low-frequency position error while positioning control amplifies high-frequency vibration amplitude. To overcome this contradiction across the whole control bandwidth, a pair of Fractional-Order Filters (FOFs) is adopted in the PFC system, which increases the flexibility in the PFC design by introducing fraction orders. The system stability analysis indicates that the FOFs can provide a better stability margin than the Integral-Order Filters (IOFs), so the control gains are increased to get a better performance on the AVI and positioning. The PFC based on FOFs can suppress the peak amplitude at the natural frequency which cannot be avoided when using the IOFs. The constrained nonlinear multivariable function is formed by the required performance and the stability of the system, then the controller parameters are optimized effectively. Lastly, the effectiveness of the proposed method is verified by experiments.

Mixed-Sensitivity H∞ Control and µ Analysis of Active Automobile Suspension

2004 ◽  
Author(s):  
Hemanth Porumamilla ◽  
Atul G. Kelkar
Keyword(s):  
Transfer Functions ◽  
Ride Comfort ◽  
Controller Design ◽  
Contemporary Literature ◽  
Pi Controller ◽  
Closed Loop System ◽  
Automobile Suspension ◽  
Performance Problem ◽  
Robust Control Design ◽  
Nominal Performance

This study presents an H∞-based robust control design for an active automobile suspension system and compares its performance with a previously designed robust LQG controller and a well tuned PI controller from contemporary literature. The robustness of the controller designs is assessed by performing μ analysis of the closed loop system. The H∞ problem is formulated as a stacked nominal performance problem. The weighting functions on complementary sensitivity, sensitivity, and controller transfer functions are chosen to obtain desirable trade-off in performance and robustness. The main objective of the controller design is to provide ride comfort for passengers. The controller design presented in this paper is shown to provide robust stability as well as desirable robust performance which is an improvement over the previously designed robust LQG controller and a PI controller chosen from contemporary literature.

Robust time optimal controller design for hard disk drives

1999 ◽  
Vol 35 (5) ◽  
pp. 3598-3600 ◽  
Author(s):  
Bong Keun Kim ◽  
Wan Kyun Chung ◽  
Ho Seong Lee ◽  
Hyun-Taek Choi ◽  
Il Hong Suh ◽  
...  
Keyword(s):  
Controller Design ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Optimal Controller ◽  
Disk Drives ◽  
Time Optimal
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