X thrust Y thrust

Introduction

Asymmetric Acceleration Drive in Various Directions on a Plane Using 2-DOF Linear Oscillatory Actuator Takamichi Yoshimoto, Yoshinori Kono, Katsuhiro Hirata

OSAKA

UNIVERSITY

Results

Conclusion

Proposed Actuator

Hirata Laboratory – Intelligent Actuators and Sensors

Basic Structure and Operating Principle

Analyzed Model and Condition

• Proposal linear oscillatory actuator that can be driven in various directions on a plane.

• Clarification of the dynamic characteristics of the actuator under asymmetric acceleration –method for non-grounded unidirectional force feedback- drive by using 3-D FEM analysis.

Haptic -sense of touch- feedback devices without grounded structure have been designed recently. However, these devices are not suitable for incorporation into mobile devices because of their size or require complex control.

2. Dynamic Analysis

1. Static Analysis

X axis drive Y axis drive

Biaxial drive

x y

z Coils

Maximum RMS current (A) 0.8

Coil 1 resistance () 3.8

Coil 2 resistance () 4.3

Number of turns (turn) 188

X axis

Mass of mover (g) 44.4

Spring constant (N/mm) 75.32

Viscous damping coefficient (N·s/m) 0.32

Y axis

Mass of mover (g) 52.8

Spring constant (N/mm) 75.32

Viscous damping coefficient (N·s/m) 0.32

Number of elements 550,800

Number of edges 650,493

Number of unknown variables 634,805

Number of steps 9999

Time division (μsec) 200

Total CPU time (hours) 600

Intel Core™i7, CPU 3.06GHz

• Small-sized two-DOF oscillatory actuator is proposed. • The static and dynamic characteristics of the actuator

are calculated by 3-D FEM. Asymmetric acceleration for illusion of haptic feedback can be observed.

• In the near future, we will make a prototype and verification of this actuator’s dynamic characteristics will be conducted by comparing the empirical data with that from 3-D FEM analysis.

Magnet

Stator yoke

Y-coil

X-coil

Stator

Mover Mover yoke

x

y

z Magnetization

N

N S

S

Force

-8.0

-4.0

0.0

4.0

1.80 1.85 1.90 1.95 2.00

acce

lera

tion

(m

/s2)

-6.0

-3.0

0.0

3.0

6.0

1.80 1.85 1.90 1.95 2.00

vo

ltag

e (V

)

-8.0

-4.0

0.0

4.0

1.80 1.85 1.90 1.95 2.00

acce

lera

tio

n (

m/s

2)

-6.0

-3.0

0.0

3.0

6.0

1.80 1.85 1.90 1.95 2.00

vo

ltag

e (V

)

-8.0

-4.0

0.0

4.0

1.80 1.85 1.90 1.95 2.00

acce

lera

tio

n (

m/s

2)

-6.0

-3.0

0.0

3.0

6.0

1.80 1.85 1.90 1.95 2.00

vo

ltag

e (V

)

-6.0-3.00.03.06.0

1.28 1.33 1.38 1.43 1.48

time(s)

x axis y axis

-6.0-3.00.03.06.0

1.28 1.33 1.38 1.43 1.48

time(s)

x axis y axis

1. Back Ground and Previous Research

2. Application of Haptic Feedback

-6.0-3.00.03.06.0

1.28 1.33 1.38 1.43 1.48

time(s)

x axis y axis

-6.0-3.00.03.06.0

1.28 1.33 1.38 1.43 1.48

time(s)

x axis y axis

-6.0-3.00.03.06.0

1.28 1.33 1.38 1.43 1.48

time(s)

x axis y axis

-6.0-3.00.03.06.0

1.28 1.33 1.38 1.43 1.48

time(s)

x axis y axis-0

.5-0

.4-0

.3-0

.2-0

.10 0.1 0.2 0.3 0.4 0.5

0.0

2.0

4.0

6.0

8.0

-0.5

-0.4

-0.3

-0.2

-0.1 0

0.1

0.2

0.3

0.4

0.5

y position(mm)

y t

hru

st(N

)

x position(mm)

-0.5

-0.4

-0.3

-0.2

-0.10

0.1

0.2

0.3

0.4

0.5

-20

-10

0

10

20

-0.5-0.4-0.3-0.2-0.1

00.10.20.30.40.5

y position(mm)

x t

hru

st(N

)

x position(mm)

-0.5

-0.4

-0.3

-0.2

-0.1

0 0.1 0.2 0.3 0.4 0.5

-20

-10

0

10

20

-0.5

-0.4

-0.3

-0.2

-0.1 0

0.1

0.2

0.3

0.4

0.5 y position(mm)

y t

hru

st(N

)

x position(mm)

-0.5

-0.4

-0.3

-0.2

-0.10

0.1

0.2

0.3

0.4

0.5

0.0

2.0

4.0

6.0

8.0

-0.5-0.4-0.3-0.2-0.1

00.10.20.30.40.5

y position(mm)

x t

hru

st(N

)

x position(mm)

Navigation device for visually impaired people

CAD，Computer game

Grounded type ○Precisely force control ○Multi-DoF ☓Necessary to fix

Non-Grounded type ○Portable ☓Complex control ☓Can’t generate unidirectional force

The thrust of the mover is calculated using the Maxwell stress tensor method, and is substituted into motion equations. The position of the mover is calculated at each time step.

Using the proposed actuator, drive to obtain haptic feedback was simulated. A voltage that generates a asymmetric acceleration was applied.

These results show this actuator has good controllability that doesn't depend on the position of the mover.

De

ten

t fo

rce

Cu

rre

nt fo

rce

When both axes were operated concurrently, the acceleration waveform has almost the same shape as during single axis drive. These results show that the generation of asymmetric oscillation in various directions on a plane is possible.

In single axis drive, an asymmetric acceleration observed without interference between the axes.