Study on the mechanism design of magnetostrictive linear motor 2001 2
2001 2
Study on the mechanism design of magnetostrictive linear motor 2001 2
----------------------------------------------------------------------- --- i Abstract ------------------------------------------------------------------------ --- ii Nomenclature ------------------------------------------------------------------- - iii List of Tables and Figures --------------------------- -------------------------- iv 1 1.1 1.2 2 2.1 Self-moving cell 2.2 Self-moving cell 2.3 2.4 3 Moving cell 3.1 Moving cell 3.2 Moving cell
3.3 3.4 3.5 4 4.1 4.2 Moving cell 5 5.1 5.2 5.3 6
-. self moving cell. clamping device push device. 2 cell (guideway) cell Terfenol-D ring (shell). self-moving cell cell. clamping force (shell). cell self-moving cell cell,,
MUX(demultiplexer). feedback.
Abstract The design and test of an magnetostrictive linear motor(mlm) that operates based on self-moving cell concept is presented. The moving cell is composed of Terfenol-D linear actuator and a ring structure, and a cell train is constructed by connecting two cells in series. Since this motor uses the stroke of Terfenol-D actuators and friction force of the cells, it can essentially produce long stroke and large force. The overall performance of the MLM was measured in terms of speed and force. The pushing force is directly related with the friction force. This work is a proof-of-concept stage and investigation is necessary for realistic application.this thesis presents the development of high precision step motor using linear magnetostrictive actuators.
NOMENCLATURE σ ε α S d K R l : axial stress : strain : coefficient of thermal expansion : compliance : piezomagnetic strain constant : actuator stiffness : magnetic resistance : length of magnetic flux pass µ : permeability s Φ B N I H L : cross-sectional area of solenoid and magnetic flux : magnetic flux : magnetic flux density : number of turns of solenoid : current through solenoid : magnetic field : length of solenoid
List of Tables and Figures Table 1-1 Physical material properties of Terfenol-D Table 1-2 Comparison of Important Shape Change Material Properties Fig. 2-1 Working principle of magnetostrictive self-moving cell Fig. 2-2 Photograph of the magnetostrictive self-moving cell linear motor Fig. 2-3 Two operating modes of the motor with three cells. Fig. 2-4 Performance curve of Terfenol-D Fig. 2-5 Strain test of Terfenol-D Fig. 3-1 Photograph of 1 st prototype actuators which are connected with a link Fig. 3-2 Schematic diagram of 1 st prototype actuator Fig. 3-3 Effect of pre-load intensity at the 2 nd prototype Fig. 3-4-1 Finite element analysis result for Stiffness coefficient
Fig. 3-4-2 Finite element analysis result for Stiffness coefficient Fig. 3-4-3 Finite element analysis result for Stiffness coefficient Table 3-1 Maximum transverse displacement and stiffness coefficient of the shell Fig. 3-5 Schematic diagram of 2 nd prototype actuator Fig. 3-6 Displacement output of the shell of the 2 nd prototype Fig. 3-7 Finite element analysis result for optimizing transverse displacement of 2 nd prototype shell (before). Fig. 3-8 Schematic diagram of control factors Table 3-2 Dimension of control factors Fig. 3-9-1 Finite element analysis result for of dimension of control Factors Fig. 3-9-2 Finite element analysis result for of dimension of control Factors Fig. 3-9-3 Finite element analysis result for of dimension of control Factors Table 3-3 2 7 level L8 (layout & data)
Table 3-4 Determine contribution and select the optimal Level Table 3-5 F o verification for optimal level Fig. 3-10 Finite element analysis result for optimizing transverse displacement of 2 nd prototype shell(after) Fig. 3-11 Detail of guideway which consists of six assembling screws, a pair of walls and a bottom rail Table 4-1. The front actuator s property: time delay and stroke at 3[A] Table 4-2. Static-friction force and minimum agitated current of the front/rear actuators. Fig. 4-1 Photograph of the experimental set up for the front/rear actuators static-friction force Fig. 5-1 Schematic diagram of experimental setup for the magnetostrictive self-moving cell linear motor. Fig. 5-2 Displacement vs. input Fig. 5-3 Speed vs. frequency at various input currents. Fig. 5-4 Load characteristic of the magnetostrictive self-moving cell linear motor, 25Hz
1 1.1 (smart material) MEMS(Micro- Electro Mechanical System),,. (unit step motion).. (piezoelectric material).,, ER, MR, Terfenol-D
. (piezoelectric material) (direct effect). (converse effect) (sensor) (actuator). PZT(lead zirconate titanate)[1] PVDF(polyvinylidene fluoride)[2]. PZT. PVDF PZT PZT. PVDF.. [3]. (shape memory alloy ; SMA). (shape memory effect ; SME) (superelasticity).. Terfenol-D. (magnetostrictive material). 1840 James Joule [4]. 1m 50ppm(50µm)
.,, (terbium) 1000ppm(1m 1mm).. A. E. Clark (terbium) (dysprosium),, (magnetic transition metal) terbium-iron(tbfe 2 ),., Dale McMaster., Tb x Dy 1-x Fe 2 Terfenol-D [5]., (+). preload. (magnetic bias) DC (bi-direction).,. Table 1-1 Terfenol-D
., (Young s Moduus)., (tensile strength) (compressive strength).. Terfenol-D. Terfenol-D 1000ppm, (permeability) 3~7. Table 1-2 Terfenol-D PZT, Terfenol-D PZT, (energy density) PZT. PZT. Terfenol-D. PZT. PZT. force-density,.,
(wave type) (hybrid) [1-6]. stator stator. stator.. (inchworm). (clamping actuators) (push actuator). stator., (holding force),.,, [7]. self-moving cell. 1.2
2 selfmoving cell, self-moving cell. 3 self-moving cell moving cell. moving cell (guideway). 4 self-moving cell 2 moving cell. (time delay) Terfenol-D (stroke).. 5,. 6.
Table 1-1 Physical material properties of Terfenol-D Mechanic al Electrical Magnetostrictiv 3 Density 9250kg / m Young,s Modulus Tensile Strength Compressive Strength Resitivity Curie Temperature Strain Production 25 35GPa 28 MPa 700 MPa 60 10 8 380 0 C Ω m 800 1200ppm e 3 Energy Density 14 25kJ / m Magnetostrictiv e-mechanical Relative Permeability 3 10
e-mechanical Standard Stoichiometry Permeability Standard Stoichiometry Tb Dy Fe 0.3 0.3.19 1.95 Table 1-2 Comparison of Important Shape Change Material Properties Smart Material Technology Parameter Terfenol-D PZT Saturation Strain (%) 0.15~0.2 0.075 3 Energy Density( kj / m ) 14~25 0.97 Thermal Conductivity( W / m k) Temperature Range ( 0 C ) 10.5~10.8 1.4~2.0-65 to +380-40 to +150
Cost per Unit of Energy( $ / mj) 25 100 2 2.1 Self-moving cell Fig. 2-1 a) d) 4. a) cell 2 (wall) (interference dimension) clamping force. clamping force (wall) clamping cell. a) clamping force front/rear cell. self-moving cell
. b) front cell (Terfenol-D) clamping force ( ). rear cell clamping force front cell. c) front cell rear cell. front cell clamping force. rear cell rear actuator Terfenol-D clamping force front actuator rear cell. front actuator cell. d) front/rear cell clamping force. front cell rear cell clamping force front cell push force. cell front actuator strain front cell. Fig. 2-2 moving cell. 2.2 Self-moving cell self-moving cell clamping force cell clamping force
cell. Terfenol-D push force. clamping force fail-safe lock.. force mode speed mode. Fig. 2-3. force operation mode macro motion control mode clamping force push force clamping cell. Speed operation mode micro motion control cell. 2.3 (constitutive equation) (14),(15). 1 2 ε = σ S + α T + ( H0 + H ) ( d + σ S + α T ) (2-1) 2, ε, S α. T, d.
(2-1). 1 2 ` ε = σ S + ( H ) ( d + σ S) (2-2) 2 (2-2)., (2-2) (equivalent force). ( ε σ S) A f = S (2-3) N H = I (t) (2-4) L (2-3)(2-4). f ( t) = K I ( t) (2-5) 2 ( S + d) N A K = σ (2-6) 2 2S L, K, L. (actuating force). 2. 4. (2-4).
. 0.75[mm] 2.5[ (1.1A)/ ] 2.7[A] 810 0.04[m] 700 [oersted].. Fig. 2-4 Fig. 2-5 ETREMA PRODUCTS, INC Terfenol-D strain.
Clamping Forces Motor at rest 1st cell activated 2nd cell activated Moving End of one period
Fig. 2-1 Working principle of magnetostrictive selfm o v i n g c e l l linear motor.
Fig. 2-2 Photograph of the magnetostrictive self-moving cell linear motor Front Shell Terfenol-D Rear Shell Walls Transferred Shell Link Speed Operation Mode Having the twice moving distance Force Ope ration Mode Reinforce the clamping force Moving direction
Fig. 2-3 Two operating modes of the motor with three cells. Strain 10-3 2 1.5 1 0.5 0 5000 Magnetic field(oe) -5000 10 20 50 40 30 Prestress(MPa)
Fig. 2-4 Performance curve of Terfenol-D 2000 LAMBDA(+/-10) 1500 1000 500 0-2 -1 0 1-2 H(+/-30 Oe)(Thousands)
Fig. 2-5 Strain test of Terfenol-D 3 Moving cell 3.1 moving cell self-moving cell cell. clamping force cell. Fig. 3-1 2 cell link cell train.
moving cell 2 (Terfenol-D) Terfenol-D. 2, Terfenol-D pre-load pre-load (Fig. 3-2). pre-load pre-load. prestress. prestress Terfenol-D prestress. Fig 3-3 prestress. pre-load.. cell Terfenol-D (solenoid). brass. 3.2 Moving cell Ring clamping force
cell stiffness FEM. Fig. 3-4 cell mesh. ANSYS (Table 3-1) 7725N/mm 0.1mm 772.5N clamping force. 3.3 Fig. 3-5 2 nd prototype, 1 st prototyper clamping action pre-load pre-load. 2 nd prototype clamping force.. dominated dimension. Fig. 3-6 FEM 2 nd prototype transverse longitudinal. 3[A]
33µm, 21.3µm FEM 33µm Fig. 3-7 21.8µm. (Fig. 3-6)2% 3 CADvolume FEM. Fig. 3-8 control factor 5 Table 3-2 control factor level 1, 2. Fig. 3-9 L8 8 control factor FEM. 2 7 L8 (Table 3-3) Avg. y, MSD y S/N ratio. Table 3-4 transverse outer diameter(a) transverse inner diameter(b) transverse outer diameter(a) off-center of transverse outer diameter(c) transverse inner diameter(b) thickness(d) transverse outer diameter(a), off-center of transverse outer diameter(c) longitudinal outer dimension(e). A-level1, B-level2, C-level1, D-level1 E-level1 F 0 (Table 3-5) A 99%, E 95%, C 90%. Fig.3-10 FEM. 15%
clamping force (stall force), (static friction force) (minimum activation current). 3.4 cell (normal frictional force). - self-moving cell. cell train Fig. 3-11, 1 (bottom rail) (assembling screw)., 2, 1. cell (normal force). Cell train.,. (assembling screw)
..... (bottom rail) pre-load. pre-load. pre-load 2. foil. Front Actuator Link Rear Actuator
Fig. 3-1 Photograph of 1 st prototype actuators which are connected with a link Pre-load Screw Terfenol-D Solenoid Shell Jointed Hole
Fig. 3-2 Schematic diagram of 1 st prototype actuator Displacement of longitudinal direction[mm] 0.05 0.04 0.03 0.02 0.01 Pre-loaded Terfenol-D More Pre-loaded Terfenol-D 0.00 0 1 2 3 4 Current[A]
Fig. 3-3 Effect of pre-load intensity at the 2 nd prototype Load 2[N] Load 20[N] Load 40[N]
Fig. 3-4-1 Finite element analysis for 1 st prototype stiffness at transverse direction Load 60[N] Load 100[N]
Fig. 3-4-2 Finite element analysis for 1 st prototype stiffness at transverse direction Table 3-1 Maximum transverse displacement and stiffness of 1 st prototype shell Load[N] Maximum displacement [m m] Stiffness [N/mm] 2 0.259 7722 20 2.589 7724.9 40 5.178 7724.9 60 7.767 7725
100 12.943 7726.2 Pre-load Screw Terfenol- D Solenoid Shell Jointed Hole
Fig. 3-5 Schematic diagram of 2 nd prototype actuator 0.05 Displacement[mm] 0.04 0.03 0.02 0.01 Transverse Dircetion Longitudinal Direction 0.00 0 1 2 3 4 Current[A]
Fig. 3-6 Displacement output of the shell of the 2 nd prototype V1 L3 C2 Z X Y 0.0218 0.0196 0.0175 0.0153 0.0131 0.0109 0.00873 0.00655 0.00437 0.00218 0. -0.00218-0.00437-0.00655-0.00873-0.0109-0.0131-0.0153-0.0175-0.0196-0.0218
Fig. 3-7 Finite element analysis result for optimizing transverse displacement of 2 nd prototype shell (before). Transverse outer Transverse inner Off-center of transverse outer diameter Longitudi nal outer Thickn
Fig. 3-8 Schematic diagram of control factors Table 3-2 Dimension of control factors Dimension Level1 Level2
A: Transverse outer diameter φ86 φ90 B: Transverse inner diameter φ60 φ62 C: Off-center of transverse outer diameter 10 9 D: Thickness 10 8 E: Longitudinal outer diameter φ80 φ75 1st 2nd
4th 5th
7th
Table 3-3 2 7 level L8 (layout & data)
A B C D E A-C A-B Avg.y MSD y 1 2 3 4 5 6 7 Result S/N Ratio 1 1 1 1 1 1 1 1 21.83 2183 476.54 9 29.7914 2 1 1 1 2 2 2 2 20.31 2031 412.49 6 29.1645 3 1 2 2 1 1 2 2 22.01 22.01 484.44 29.8627 4 1 2 2 2 2 1 1 18.99 18.99 360.62 28.5808 5 2 1 2 1 2 1 2 14.64 14.64 214.33 26.3211 6 2 1 2 2 1 2 1 15.61 15.61 7 2 2 1 1 2 2 1 16.05 16.05 8 2 2 1 2 1 1 2 18.17 18.17 243.67 2 257.60 3 330.14 9 26.8784 27.1198 28.1974
Table 3-4 Determine contribution and select the optimal Level A B C D E A-C A-B SUM Level 1 117. 4 112. 2 114. 3 113. 1 114. 7 112. 9 112. 4 Level 2 108. 5 113. 8 111. 6 112. 8 111. 2 113. 0 113. 5 225.9 Ra 8.88 3 1.60 5 2.63 0 0.27 4 3.54 4 0.13 5 1.17 5 18.25 Contribution (%) 48.6 8 8.79 9 14.4 1 1.50 1 19.4 3 0.73 8 6.44 2 100 Optimal Level A1 B2 C1 D1 E1 Factor T.O.D T.I.D O.T.O.D Thickness L.O.D φ86 φ62 10 10 φ80
Table 3-5 F o verification for optimal level Factor S Pi V F0 F(0.10) F(0.05) F(0.01) A 9.862783 1 9.8627 8 B 0.322142 1 0.3221 4 C 0.864673 1 0.8646 7 D 0.009381 1 0.0093 8 E 1.569648 1 1.5696 5 A-C 0.002267 1 0.0022 7 A-B 0.172692 1 0.1726 77.892 6-6.8288 7-12.396 5 4.54 7.71 21.2
9 (e) 0.506481 4 T 12.80359 7 0.1266 2 V1 L1 C1 Z X Y 0.0252 0.0227 0.0202 0.0176 0.0151 0.0126 0.0101 0.00756 0.00504 0.00252 0. -0.00252-0.00504-0.00756-0.0101-0.0126-0.0151-0.0176-0.0202-0.0227-0.0252
Fig. 3-10 Finite element analysis result for optimizing transverse displacement of 2 nd prototype shell(after) Bottom Rail Walls Assembling Screws
Fig. 3-11 Detail of guideway which consists of six assembling screws, a pair of walls and a bottom rail 4 4.1 (Terfenol-D) cell
self-moving cell cell. Table 4-1 actuator. 5Hz 9[msec] 10Hz 0.1[msec/Hz]....... 4.2 Moving cell Fig. 4-1 cell. Table 4-2 2.2N 2.4N front
cell rear cell. (minimum activation current) cell.
Table 4-1 The front actuator s property: time delay and stroke at 3[A] Property Frequency Time delay (msec) Displacement (m m) 10 Hz 5Hz 9.3 22.62 15.2 23.08 15 Hz 15.6 22.34 20 Hz 16.1 22.2 25 Hz 16.6 21.6 Table 4-2. Static-friction force and minimum agitated current of the front/rear actuators. Property Static-friction Minimum activation Actuator Force[N] current[a] Front 2.43 0.7 Rear 2.26 0.8
Fig. 4-1 Photograph of the experimental set up for the front/rear actuators static-friction force 5
5.1 Fig. 5-1 self-moving cell 1 st prototype. DSP board half sine wave. half sine wave moving cell overshoot. DSP board 2 (HP6268B) Terfenol-D solenoid, Terfenol-D. Current probe proximeter(bently NEVADA). rear actuator proximeter. 5.2 Fig. 5-2 5Hz, 25Hz. Proximeter cell. cell cell train
. Cell train cell (guideway). 4. Fig. 5-3 selfmoving cell. cell (guideway). (external load). Fig. 5-4 self-moving cell. 1.2A 0.017mm/sec, (stall) 1N. clamping cell.. 5.3 self-moving cell
1 st prototype. 2 nd prototyped, Mux 2 cell. D.C power supply Signal analyzer DSP board Proximitor
Fig. 5-1 Schematic diagram of experimental setup for the magnetostrictive self-moving cell linear motor. 0.04 Displacement Input current 2.0 0.03 1.5 Displacement[mm] 0.02 0.01 0.00-0.01 1.0 0.5 Current[A] 0.0-0.02-0.03-0.5 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 Time[sec] a. 5Hz
Fig. 5-2 Displacement vs. input
0.10 Speed [mm/sec] 0.08 0.06 0.04 0.02 1.2 [A] 1.6 [A] 1.8 [A] 2 [A] 0.00 0 5 10 15 20 25 Frequency [Hz] Fig. 5-3 Speed vs. frequency at various input currents.
0.05 Speed [mm/sec] 0.04 0.03 0.02 1.2[A] 1.6[A] 1.8[A] 2[A] 0.01 0.00 0.0 0.5 1.0 1.5 2.0 2.5 Load [N] Fig. 5-4 Load characteristic of the magnetostrictive self-moving cell linear motor, 25Hz
6 Self-moving cell. push force cell self-moving cell cell. self-moving cell, cell,. FEM.
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