1 Haptic Systems 530-655 Mohsen Mahvash Lecture 3 11/1/06.

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1 Haptic Systems 530-655 Mohsen Mahvash Lecture 3 11/1/06

Transcript of 1 Haptic Systems 530-655 Mohsen Mahvash Lecture 3 11/1/06.

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Haptic Systems 530-655

Mohsen Mahvash Lecture 311/1/06

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A review of the last lecture

The definition of haptic rendering

Haptic simulation of a spring

Haptic simulation of the gravitational forces between two objects

Examples of force functions

Haptic rendering of contact

Physically based haptic rendering and the challenges

References

Introduction to Haptic Rendering

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A Review of the Last Lecture

Tip

SensAble Phantom Omni

FJ T

iii Ik

),,( 321 pX JX

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“Haptic rendering is the process of computing and generating forces in

response to user interaction with virtual environment”

Computing forces and torques that should be applied to the tip of the

haptic display in order to represent forces of a physical phenomena

or represent some data

Tip

The definition of haptic rendering

F

F

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Haptic Simulation of a Spring

Fp

0p0ppd

kdF ),,( 321 ntipPositiop

Algorithm for

simulation of spring

}0,0,0{0 p

0ppd kdF FJ T

//Virtual spring

i

ii kI

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Haptic simulation of the gravitational forces between objects

0c

0cpd

dud

kF

2||

|| d

dud

p

R

Rd ||For

For Rd || dkF 2

d

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Haptic simulation of the Solar System

321 FFFF

p 2c

1c3c

Calculate gravitational forces for every sphere and then add

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Examples of force functions

)(tfF A function of time

A function of tip position or tip displacement of time )( 0ppfF

A function of tip Velocity)(

dt

dpfF

),,,(2

2

0 dt

dp

dt

dppptfF A general function

You may not be able to implement some general functions

(Because of high order derivatives)

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Haptic simulation of contact

)( cpkF NF 100F

0t sec1t sec2t

cp god object

proxy

contact point

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Haptic simulation of contact

nudkcpkF ||)( 11

1c1p0c

0p

1c

nu

c

tt uucpc )).(( 01 0t 1t

|| d

1p :unit vector normal to surfacenu

tu

:unit vector tangent to surfacetu

1p

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Haptic simulation of contact

Haptic Scene

Rigid or Deformable

Graphic Scene

Deformable objectGraphic Scene

Rigid object

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Rigid and Deformable Objects

Deformable bodies: Location , geometry, frictional properties

, material, support, internal structure

Rigid bodies: Location, geometry and

frictional properties

)( 0cpkF

),,( 00 cdt

dpcpfF

0cp

Elastic material

Viscoelastic

material

),( 00 ccpfF

Plastic

material

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Haptic Rendering of Deformable Objects

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Physically Based Haptic Rendering and the Challenges

Rendering forces should depend on material properties

It is very time-consuming to calculate rendering forces from material properties using conventional engineering approaches such as Finite Element Methods

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Tomorrow

Real-time programming for haptics

References

1. Salisbury, K., Brock, D., Massie T., Swarup, N., Zilles, C. 1995. Haptic Rendering: Program-ming Touch Interaction with Virtual Objects. Proc. Symposium on Interactive 3D Graphics, ACM. pp. 123-130

2. 3D Touch™ SDK OPENHaptics™TOOLKIT, Programming Guide, http://www.sensable.com/

3. Mahvash, M., Hayward, V. 2004. High Fidelity Haptic Synthesis of Contact With Deformable Bodies. IEEE Computer Graphics and Applications. 24(2): 48-55, 2004