K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems Mechatrnic Design f Hard Disk Drives: single and dual stage Dr. Hamid D. Taghirad Advanced Rbtics and Autmated Systems (ARAS) Department f Electrical Engineering K.N.Tsi University f Technlgy HDD Tutrial,.
Outline Intrductin Hard Disk Drive Specificatin Perfrmance Requirements Mechatrnic Design Cntrller Design Signal Generatin ARC Cntrl Perfrmance Imprvement Dual Stage HDD ARC Cntrller design Rbust Perfrmance Cnclusins HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 2
Hard Disk Drive Specificatins HDD is a nn-vlatile strage device which stres digitally encded data n rapidly rtating platters with magnetic surfaces. Invented By: Reynld Jhnsn Date Invented: Sept.13, 1956 HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 3
HDD Specificatins HDD Technlgy Recrd data : magnetizing a magnetic material in a pattern that represents the data. Read data: detecting the magnetizatin f the material HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 4
HDD Specificatins Bit-cell magnetic grains 50-100 grains/bit 0 : Regin f grains f unifrm magnetic plarity 1 : Bundary between regins f ppsite magnetizatin HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 5
HDD Specificatins HDD Cnsists f A Spindle: hlds ne r mre platters. (10,000 RPM!) The platters: nn-magnetic material (glass r aluminum) cated with a thin layer f magnetic material. (cbalt-based ally) HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 6
HDD Specificatins HDD Cnsists f Read-Write Head: Multiple heads n a cmmn arm HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 7
HDD Specificatins HDD Cnsists f Read-Write Head (Air Gap Nanmeter!) HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 8
HDD Specificatins HDD Platter Damage: (Air Gap Nanmeter!) HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 9
HDD Specificatins HDD size Standard name 5.25" 3.5" 2.5" 1.8" (PCMCIA) 1.8" (ATA-7 LIF) Width 5.75" 4" 2.75" 54 mm 2.12" HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 10
HDD Specificatins Data Track: sub-micrmeter-sized magnetic regins HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 11
HDD Perfrmance Requirement 1050 1040 1030 1020 Fast Transient Lw Capacity HDD Accuracy Micr meter 1010 1000 990 980 Sub-Micrn Psitining 970 Seeking Mde Fllwing Mde 8 10 12 14 16 18 20 22 time ms HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 12
HDD Mechatrnic Design Marketing reliability Material Mechanical Cntrl Electrical Cmmunicatin cmputer HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems
HDD Mechatrnic Design Access Time Rtatinal Speed Transient Time N Switching Cntrl RPM 4200 5400 7200 10000 Access Time (ms) 7.14 5.55 4.17 3 HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 14
HDD Mechatrnic Design HDD Capacity Track Density Mdern Cntrller Imprved Psitining Perfrmance Disturbance Rejectin HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 15
HDD Mechatrnic Design Mechanical High RPM Vibratin Cntrl Air Cushins Material Disk Surface Flatness Data Density HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 16
HDD Mechatrnic Design Electrical & Cmputer R/W Head Vice Cil Mtr Embedded Prcessr HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 17
HDD Mechatrnic Design Electrical & Cmputer Hst Interface Buffer Cntrller Disk Sequencer ECC Serv Cntrl CPU Buffer Memry CPU Memry Data Channel HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 18
HDD Mechatrnic Design Reliability Key metric MTBF MTBF fr SCSI disk: 1,200,000 hurs Factrs Affecting Reliability Duty Cycle N. f Platters Temperature HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 19
HDD Mechatrnic Design Marketing Cst per Capacity Flash Memry Cst per megabyte 250 1 0.9 200 0.8 0.7 0.6 Dual Stage HDD 0.5 150 0.4 0.3 $ 0.2 100 0.1 0 1994 1995 1996 1997 1998 1999 2000 50 0 1980 1981 1983 1984 1985 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 20
HDD Cntrller Design Heart f Mechatrnic Design: Cntrller Design Material and Mechanical Cnstrains Signal Generatin Access Time Mdern Cntrller Unified Structure Such as r ARC Switching Mde Capacity Mdern Cntrller H Imprved Psitining Perfrmance Disturbance Rejectin HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 21
HDD Cntrller Design Literature Review 1971 IBM Merlin 3330 The first HDD which used disk psitin infrmatin n feedback. 1973 IBM Winchester 3340 The first HDD with embedded cntrller. Bang Bang Cntrl (Dick Oswald) Prximate Time Systems (PTS) Prximate Time ptimal Systems (PTOS) Mdern Cntrller Mde Switching Rbust cntrllers Adaptive Rbust Cntrllers HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 22
HDD Cntrller Design Tw decay f Bang-Bang Cntrl 1 0.8 0.6 0.4 0.2 0-0.2-0.4-0.6 1 0.8 0.6 0.4 0.2 0-0.2-0.4-0.6 v/vmax (-.) Velsity prfile 0.6 u, v, and y Open-lp Bang Bang cntrl 1 0.8 0.4 0.2 0-0.2-0.4 Open-lp Bang Bang cntrl y/yref y/yref (Psitin (slid) prfile) Psitin prfile Prximated Time Optimal System v/vmax (-.) (Velsity prfile) 700 v/v max 500 y/y u des Track 600 400 300 650 track seeking and fllwing IDCARC (slid) and PTOS (dash) -0.8-0.6 a/amax(:) 200-0.8 (Acceleratin a/amax (:) prfile) -0.8 Acceleratin prfile -1 0 0.5 1 1.5 2 2.5 3 100-1 3.5 4 4.5 5 0 1 Time 2 (sec) 3 4 5 x 10 Open lp Bang Bang -3 6 7-1 0 0.5 1Time (sec) 1.5 2 2.5 3 3.5 x 10 Clse lp Bang Bang -3 4 4.5 5 Prximate 0 time time ptimal (sec) System x 10-3 0 1 2 3 4 5 6 7 8 Time (ms) PTOS & IDCARC HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 23
HDD Cntrller Design Unified Cntrller Structure Cntrller y d.. a d α y d + 1 h 4ξ k 2 ' u s1 us2 + + u a + d + K t Plant 1 Js + B 1 s Signal Generatin. ^ k 1 + s θ θ = Prj( Γϕ p) d ^ u ^ a ϕ d θ HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 24
HDD Cntrller Design On-line Signal Generatin k e U + 1 1 1 v 1 y k Ls + R t c J s s B Jerk minimizatin With effect f frictin J = T 0 du dt 2 dt v( t ) v max u max u = cv k v e max 1.Accel. i( t ) i set k sw u min HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 25
HDD Cntrller Design Adaptive Rbust Cntrl (ARC) What is ARC Rbust Cntrl Law Learning Mechanism (Parameter Adaptatin) Adjustable Mdel Cmpensatin Crdinatin Mechanism Why ARC HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 26
HDD Cntrller Design HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 27
HDD Cntrller Design HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 28
HDD Cntrller Design HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 29
HDD Cntrller Design Unified Cntrl Structure (ARC) θˆ 1 s θ ˆ Pr j ( Γ ˆ ϕ( x) p) θ u s Rbust Feedback ϕ( x) T ˆ θ u a x T = ϕ ( x) θ + + u x e PD p Adjustable Mdel Cmpensatin Plane Plant x d HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 30
HDD Cntrller Design Desired Cmpensatin ARC θˆ 1 s θ ˆ Pr j ( Γ ˆ ϕ( x) p) θ u s ϕ( x) T ˆ θ ua T x = ϕ ( x) θ + + u Plant x e x d p θˆ 1 s θ ˆ Pr j ( Γϕ ˆ d ( x) p) θ ϕ ( x) d T ˆ θ u a u s Rbust Feedback T x = ϕ ( x) θ + + u x e PD p Adjustable Mdel Cmpensatin Plant Plane x d HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 31
HDD Cntrller Design Imprved DC ARC Disturbance attenuatin Gd tracking in seeking mde Accuracy in fllwing mde θˆ k s +1 θ ˆ Pr j ( Γϕ ˆ d ( x) p) θ ϕ ( x) d T ˆ θ ua u s x T = ϕ ( x) θ + + u x e p Plant x d HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 32
HDD Cntrller Design Imprved Desired Cmpensatin Adaptive Rbust Cntrl θˆ k s +1 θ ˆ Pr j ( Γϕ ˆ d ( x) p) θ Cntrller T ϕ ( x) ˆ θ d ua u s T x = ϕ ( x) θ + + u x e p Plant x d y d.. a d α y d + 1 h 4ξ k 2 ' u s1 us2 + + u a + d + K t Plant 1 Js + B 1 s Signal Generatin HDD Tutrial,. ^ k 1 + s θ θ = Prj( Γϕ p) d ^ u ^ a ϕ d θ K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 33
HDD Cntrller Design Cntrller Perfrmance: Tracking 1200 1000 1050 800 1040 Micr meter 600 400 Micr meter 1030 1020 1010 1000 200 990 980 0 970 8 10 12 14 16 18 20 22 time ms -200 0 5 10 15 20 25 30 time ms HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 34
HDD Cntrller Design Cntrller Perfrmance: Tracking errr HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 35
HDD Cntrller Design Cntrller Perfrmance: Actuatr effrt HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 36
HDD Cntrller Design Cntrller Perfrmance: Parameter Estimatins HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 37
HDD Cntrller Design Cntrller Perfrmance: Transient Imprvement HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 38
Dual Stage HDD Descriptin VCM 1 st Actuatr PZT 2 nd Actuatr HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 39
Dual Stage HDD Vice Cil Mtr (VCM) Large Operating Range Lw Resnance Frequency Curse Psitining HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 40
Dual Stage HDD Piez-Electric Transducer (PZT): Push-Pull type Small Operating Range High Resnance Frequency Fine Psitining HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 41
HDD Dynamic Mdels VCM Nnlinear Mdel Uncertain Linear Mdel Experimental Frequency Respnse Estimates x 1 = x 2 Jx 2 = u B x 2 A S ign ( y ) F + F + F y = x 1 f hys hi d ( ) ( ) 1 ( ) ( ) 0 ( jω ) ( jω ) ( ) ( ) P s Π P s = + s W s P s P P ( jω) 1 W, ω Laser-Dppler-Scanning Vibrmeter (LDV) HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 42
HDD Dynamic Mdels VCM Experimental Mdel VCM-mdel Lg. Magn. [µ m/v] 10 0 Reduced mdel Nminal mdel 10 2 10 3 10 4 Frequency [Hz] 0 Phase [deg] -500-1000 -1500 HDD Tutrial, 10 2 10 3 10 4 Frequency [Hz] K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 43
HDD Dynamic Mdels VCM Mdel Uncertainty Multiplicative VCM-Uncertainty 10 1 10 0 10-1 10 2 10 3 10 4 Frequency [Hz] HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 44
HDD Dynamic Mdels PZT Experimental Mdel PZT-mdel Lg. Magn. [µ m/v] 10 0 Nminal mdel Reduced mdel 10 2 10 3 10 4 Frequency [Hz] 600 400 Phase [deg] 200 0-200 -400 HDD Tutrial, 10 2 10 3 10 4 Frequency [Hz] K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 45
HDD Dynamic Mdels PZT Mdel Uncertainty Multiplicative PZT-Uncertainty 10 1 10 0 10-1 HDD Tutrial, 10 2 10 3 10 4 Frequency [Hz] K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 46
HDD Dynamic Mdels Nminal Mdels VCM = G V CM, reduced 2 s 7 8.119 10 + 460.3s + 853776 PZT 1.343 10 + 21000s + 2.25 10 8 G PZT, reduced = 2 8 s HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 47
HDD Cntrller Design Pre-Filter Design Reduced Mdel N Unstable zers! HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 48
HDD Cntrller Design Pre-Filter Design 4 s + (0.07 ± 6.7 j) 10 PVCM = K1 4 4 4 ( s + 5.56 10 )( s + 2.6 10 )( s + (2.4 ± 7.4) 10 ) -60 Bde Diagram -80 Magnitude (db) -100-120 -140-160 -180 0 Phase (deg) -180-360 -540-720 VCM; rder 12 Cmpensated VCM 10 3 10 4 Frequency (rad/sec) HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 49
HDD Cntrller Design Pre-Filter Design 4 4 ( s + (0.03± 6.7 j) 10 )( s + (1.4 ± 8.4 j) 10 ) PPZT = K2 2 2 4 5 5 ( s + 2 ωξs + ω )( s + (0.58 ± 7.7) 10 )( s + 1.24 10 )( s + 4.36 10 ) Bde Diagram -80 Magnitude (db) -100-120 -140 Phase (deg) -160 0-45 -90-135 -180-225 -270 PZT; rder 10 Cmpensated PZT 10 3 10 4 Frequency (rad/sec) HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 50
HDD Cntrller Perfrmance Nminal Tracking errr R & Y [ µ m ] E=R-Y [ µ m ] 2000 1000 Ttal Respnce 0 0 5 10 15 20 25 30 Time[msec] Ttal Seeking Errr 40 20 0-20 -40 0 1 2 3 4 5 6 7 Time[msec] Ttal Traking Errr HDD Tutrial, E=R-Y [ µ m ] Ev=R-Yv [ µ m ] 0.5 0-0.5 10 0-10 10 15 20 25 30 Time[msec] Traking Errr fr VCM 10 15 20 25 30 Time[msec] K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 51
HDD Cntrller Perfrmance Cntrller Perfrmance: Nminal Cntrl Effrt 30 Cntrl Effrts VCM Input [v] 20 10 0 0 5 10 15 20 25 30 Time[msec] 20 MA Input [v] 10 0-10 -20 0 5 10 15 20 25 30 Time[msec] HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 52
HDD Cntrller Perfrmance Cntrller Perfrmance: Rbust Tracking errr R & Y [ µ m ] E=R-Y [ µ m ] E=R-Y [ µ m ] Ev=R-Yv [ µ m ] 2000 1000 Ttal Respnce 0 0 10 20 30 40 50 60 70 80 Time[msec] Ttal Seeking Errr 0-50 10 0-10 -20 0-10 -20-30 0 1 2 3 4 5 6 7 Time[msec] Ttal Traking Errr 10 20 30 40 50 60 70 80 Time[msec] Traking Errr fr VCM 10 20 30 40 50 60 70 80 Time[msec] HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 53
HDD Cntrller Perfrmance Cntrller Perfrmance: Rbust Cntrl Effrt 150 Cntrl Effrts VCM Input [v] 100 50 0 0 10 20 30 40 50 60 70 80 Time[msec] 25 MA Input [v] 20 15 10 5 0 0 10 20 30 40 50 60 70 80 Time[msec] HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 54
HDD Cntrller Perfrmance Cntrller Perfrmance: Quantitative Cmparisn Nminal Perfrmance in presence f Disturbance Rbust Perfrmance in presence f Disturbance and wrst case uncertainty HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 55
Cnclusins Hard Disk Drive Specificatin Perfrmance Requirements Mechatrnic Design Dual Hard Disk Drives Cntrller Design Unified Structure fr Cntrl f HDD: IDCARC Significant Tracking Errr Reductin Disturbance Attenuatin Nise Rejectin Rbust Perfrmance Dynamic Adaptatin Fast Transient + Very Accurate Psitining HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 56
References: Visit ur web site: http://saba.kntu.ac.ir/eecd/taghirad http://saba.kntu.ac.ir/eecd/aras/prjects/arc HDD.htm Papers: H.D. Taghirad and E. Jamei, Rbust Perfrmance Verificatin f IDCARC Cntrller fr Hard Disk Drives, Accepted fr publicatin in IEEE Transactins n Industrial Electrnics, 2006. H. Taghirad and P. Sheykhleslam, IDCARC Cntrller Design Fr Dual-Stage Hard Disk Drives, Accepted fr publicatin in 15th Int. Iranian Cnference n Electrical Engineering, May 2007, Tehran. H.D. Taghirad and E. Jamei, Adaptive Rbust Cntrller Synthesis fr Hard Disk Serv Systems, IEEE IROS 04, 2:1154-1159, Oct 2004, Japan. H.D. Taghirad and E. Jamei, Adaptive rbust cntrl fr hard disk serv system, In the Prceedings f the 12th Internatinal Cnference n Electrical Engineering, pp 13-18, May 2004, Mashad. HDD Tutrial, K.N. Tsi University f Technlgy Advanced Rbtics and Autmated Systems 57