Hard Disk Drive: Mechatronics and Control

by Al Mamun; Abdullah

• ISBN13: 9780849372537
• ISBN10: 0849372534
• eBook ISBN(s): 9781351838023
• Additional ISBN(s): 9781420004106
• Edition: 1st
• Format: Hardcover
• Copyright: 2006-11-02
• Publisher: CRC Press
• More Book Details

Summary

The hard disk drive is one of the finest examples of the precision control of mechatronics, with tolerances less than one micrometer achieved while operating at high speed. Increasing demand for higher data density as well as disturbance-prone operating environments continue to test designers' mettle. Explore the challenges presented by modern hard disk drives and learn how to overcome them with Hard Disk Drive: Mechatronics and Control.Beginning with an overview of hard disk drive history, components, operating principles, and industry trends, the authors thoroughly examine the design and manufacturing challenges. They start with the head positioning servomechanism followed by the design of the actuator servo controller, the critical aspects of spindle motor control, and finally, the servo track writer, a critical technology in hard disk drive manufacturing. By comparing various design approaches for both single- and dual-stage servomechanisms, the book shows the relative pros and cons of each approach. Numerous examples and figures clarify and illustrate the discussion.Exploring practical issues such as models for plants, noise reduction, disturbances, and common problems with spindle motors, Hard Disk Drive: Mechatronics and Control avoids heavy theory in favor of providing hands-on insight into real issues facing designers every day.

Table of Contents

Preface	xvii
List of Acronyms	xxiii
List of Figures	xxv
List of Tables	xxxvii
Introduction	1	(30)
History of HDD Technology	5	(2)
The Early Days	5	(1)
Emergence of Desktop Computers	6	(1)
Small Form Factor Drives	7	(1)
Components of a Hard Disk Drive	7	(10)
Head and Disk	8	(3)
Electromechanical Components	11	(5)
Mechanical and Electronic Components	16	(1)
Accessing Data in HDD	17	(5)
Arrangement of Data on the Disks	17	(1)
Locating Data	18	(2)
Track Seek and Track Following	20	(1)
Zoned Bit Recording	21	(1)
Trend in HDD Industry	22	(5)
Areal Density Growth	22	(2)
Trend in Drive Form Factor	24	(1)
Trend in Data Transfer Rate	25	(2)
Alternative Recording Technologies	27	(4)
Head Positioning Servomechanism	31	(52)
The Servo Loop	31	(4)
The Actuator	35	(10)
Measurement of Frequency Response	40	(3)
Identification of Transfer Function Model	43	(2)
Feedback of Position Signal	45	(12)
Servo Bursts	46	(5)
Servo Demodulation	51	(2)
Recent Developments	53	(4)
High Frequency Dynamics	57	(1)
Noise and Disturbances	58	(7)
Repeatable and Non-repeatable Runout	59	(2)
Pivot Friction	61	(3)
Flex Cable Bias	64	(1)
External Shock and Vibration	64	(1)
Other Sources of Noise	64	(1)
Track Seek Controller	65	(18)
Time Optimal Control	66	(4)
Proximate Time Optimal Servomechanism	70	(5)
Rejection of Input Disturbance	75	(3)
Mode Switching Control with Initial Value Compensation	78	(2)
Suppression of Residual Vibration	80	(3)
Design of Actuator Servo Controller	83	(122)
Review of Design Methods	84	(4)
Slow Dynamic Systems	85	(1)
Fast Dynamic Systems	86	(1)
Numerical Search to Find Controller Parameters	86	(2)
PID-type Control	88	(29)
Basic PID-type Controller	89	(5)
Cancelling Actuator Resonances using Notch Filter	94	(8)
Cancelling Sensor Noise using Notch Filter	102	(2)
Phase Stable Design	104	(6)
Inserting a Peak Filter	110	(5)
Summary: Application of Different Filters	115	(2)
Factors Limiting Servo Performance	117	(7)
Limitation of S + T = 1	119	(2)
Waterbed Effect	121	(2)
Bandwidth Limitations	123	(1)
Optimal Control	124	(7)
H2 Optimal Control: Continuous-time Case	125	(3)
H2 Optimal Control: Discrete-time Case	128	(1)
An Application Example	129	(2)
Advanced Topics	131	(34)
Input Command Shaping	132	(4)
Initial Value Compensation	136	(4)
RRO Compensation	140	(11)
Multirate Control	151	(4)
Multisensing Servo	155	(10)
Emergence of Dual-Stage Actuator	165	(9)
Actuated Suspension	166	(1)
Actuated Slider	167	(3)
Actuated Head	170	(2)
Microactuator for Controlling Head-Media Spacing	172	(2)
Control of Dual-Stage Actuator	174	(31)
Control Design Specifications	175	(1)
Parallel Structure	176	(8)
PQ Method	184	(2)
Decoupled Master-Slave Structure with Actuator Saturation	186	(9)
Experimental Results	195	(10)
Spindle Motor Control	205	(102)
Magnetic Field Fundamentals	205	(12)
Flux	205	(1)
Flux Density (Magnetic Induction)	206	(1)
Magnetic Field Strength, Permeability and Relative Permeability	206	(1)
Energy in Magnetic Field	207	(1)
B-H Curve	208	(3)
Magnetic Circuit and Magnetomotive Force	211	(6)
Electric Motor Fundamentals	217	(30)
MMF Generated by Distributed Winding	217	(3)
Rotating Magnetic Field, Pole-pair, Speed and Frequency	220	(4)
Force and Torque Generated by Magnetic Field	224	(12)
Cogging Torque and Unbalanced Magnetic Pull	236	(2)
Generation of back-EMF	238	(4)
Electrical Degree and Mechanical Degree	242	(1)
Armature reaction	243	(2)
Conditions of Magnetic Field for Producing Ampere's Torque	245	(2)
Spindle Motors used in HDD	247	(26)
Special Requirements for HDD Spindle Motor	247	(2)
Back-EMF in Spindle Motor	249	(2)
Load of Spindle Motor	251	(1)
Motor Configuration	252	(2)
Magnetic Ring	254	(2)
Stator Core	256	(1)
Spindle Motor Bearings	256	(6)
Winding Structure and the Airgap Field Produced by the Winding	262	(6)
Cogging Torque, UMP and Armature Reaction	268	(3)
Electromagnetic Power, Electromagnetic Torque and Motor Losses	271	(2)
Spindle Motor Drive System	273	(34)
What is the BLDC mode?	274	(2)
Detection of Rotor Position in Sensorless Drive	276	(11)
Starting of Spindle Motor	287	(4)
Spindle Motor Driven in Sensorless BLDC Mode	291	(10)
Acoustic Noise in Spindle Motor Driven in BLDC Mode	301	(6)
Servo Track Writer	307	(28)
Introduction	307	(3)
HDA Servowriting	310	(5)
Control of Tangential Position using Clock Head	310	(3)
Control of Radial Position using Mechanical Push-pin	313	(1)
Control of Radial Position using Optical Push-pin	314	(1)
Media STW	315	(2)
Self Servowriting	317	(7)
Basic Concept	318	(1)
Track Propagation	319	(2)
Clock Propagation	321	(2)
Concluding Remarks	323	(1)
A Laboratory-scale Example	324	(7)
Configuration of the System	324	(3)
Measurement and Reduction of Disk-Spindle Pack Imbalance	327	(1)
Control System	328	(2)
Test Results	330	(1)
Printing the patterns	331	(4)
Nano-Imprint	331	(1)
Magnetic Printing	332	(3)
Bibliography	335	(20)
Index	355