haptics

yardbellAI and Robotics

Nov 14, 2013 (4 years and 5 months ago)

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HAPTICS

Introduction



Haptics

is the study of how to couple the human sense
of touch with a computer generated world.



Haptic

refers to the sensing and manipulation through
touch



Haptics

is derived from the
greek

word ‘
haptien
’ which
means ‘hold’.



In combination with visual display ,
haptics

technology
can be used to train people for tasks requiring hand
-
eye
coordination
.



Contd..


The study of
Haptics

emerged from advances in
virtual reality.


Virtual reality is a form of human
-

computer
interaction providing a virtual
enviornment

that
one can explore through direct interaction with
our senses.


To be able to interact with virtual
enviornment

there must be some feedback and this type of
feedback is called
Haptic

feedback
.



Haptic

interface:device

for touch interaction in
real and virtual world.


Types


Machine
Haptics

:machines used to
simulate human touch.


Human
Haptics:study

of human sensing
through touch.


Computer
Haptics:Computational

method
to generate and render touch.


Two primary types of Haptic

interfaces


1.Force feedback(Force reflecting)



It deals with devices that interact with the
muscles and tendon that give the human a
sensation of force being applied.



These devices mainly consist of robotic
manipulators
.





Contd


2.Tactile feedback



It deals with devices that interact with the


nerve endings in the skin which indicate


heat ,pressure and texture.



These devices typically have been to indicate


whether or not the user is in contact with a
virtual object.



















Force feedback display

Tactile feedback

Haptic

interaction


Haptic

interaction uses
haptic

interfaces.


Haptic

interface devices behave like small robots
that exchange mechanical energy with a user.


We use the term device
-
body interaction to
highlight the physical connection between the
operator and device


The interaction can be in contact with any part of
operator’s body.




Contd..


An avatar is created which is the
the

virtual
representation of
haptic

interface.


User physically interacts with virtual
enviornment

through the avatar.


The operator controls the avatar’s position in
virtual
enviornment
.


Contact between the avatar and the virtual
enviornment

sets off the action and reaction
force.


Contd



From real world to virtual world and vice versa.


Two methods of interaction



Point
based:only

the end point of the
haptic

device interacts with the objects.



Ray
based:collision

are checked between the
ray and objects


Point based


Model the
haptic

probe as
a single point.


Each time the user
moves the
haptic

probe
the collision is detected.


If so then appropriate
forces are reflected back
to the user
.






Ray based


The generic probe of
haptic

device is modeled
as a line segment .


Collisions are checked
between the finite line
and virtual objects.


This approach enables
users to touch multiple
objects simultaneously.






Potential benefits


Reduction in fatigue.


Increase in productivity and comfort.


Decreased learning times.


Reduction in manipulation errors.

Commercially available Haptic
interfaces

3DOF omega haptic device


The novint falcon


Haptic master

The freedom s7


• Pantograph

Haptic

devices

Sensory information in haptic devices include:



Tactile:presence of heat,texture and pressure.


Kinesthetic:position,body movements and the
forces which act on it.


Haptic devices can also be classified according
to the no:of degrees of freedom

of the force or

motion at

the
haptic

interface device.


DOF is the no:of dimensions characterizing the
possible movements of forces exchanged b/w
the user and device.


Computer
haptics


Haptic

technology:technology

that interfaces
with the user through touch.


Haptic

rendering:process

of displaying
synthetically generated 2D/3D stimuli to the
user.


Computer
haptics

is the heart of
haptics
.






Haptic

rendering


Haptic

rendering has two main parts:


Collision detection


Collision response

Collision detection:



As a user manipulates the probe of a
haptic

device,the

new position and orientation of the
probe are acquired and collisions are detected.


If no collision has
occurred,then

the device
remains passive and no force is reflected.


Contd..


collision response


If collision is detected ,interaction forces are
calculated and conveyed to the user through the
haptic

device which provides tactual information.


Haptic

loop updates the forces around 1khz.


The opposing force acting on the user during
interaction is F=k*x.


The direction of force will be normal to the
surface.

illusions



Tendon of right arm vibrated.


Feeling of right elbow rotating away.


If subjects held their left index finger with
their right hand , they felt their left index
finger getting longer.

Applications


Games:

Gaming experience can be greatly
enhanced by applying force feedback


Multi
-
media publishing:

Currently include text,
sound, images and video.


'Mechanical Documents' could be transmitted
conveying material properties


Scientific Discovery:
Data display


Remote sensing, mining in geology (oil and gas
prospecting)



Applications(contd.)


Other fields of application


Arts and Creation:
Artists and musicians,
virtual exhibitions of paintings and sculpture


Vehicle operation:
iDrive

in BMW and Rolls
Royce


Engineering:

CAD


Education and Training:
surgical training,
pilot training


Current activity


TapTap

is a wearable haptic interface.



It can record and play back patterns of tactile
information so that people can experience the
emotional and physical benefits of human touch
in different times and places.


Actuators are present to provide the various
touch sensations.


Downsides of
Haptics


Haptic

applications can be extremely complex
requiring specialized hardware and processing
power.


Many
haptic

projects rely on fixed installations
and they are not easily portable.


Cost is high .

Conclusion


Haptics

plays an important role in
constructing an autonomous robot.


Although
haptic

interface devices are
available, further improvements are needed
to match the performance of the human user.


Tactile display is one of the most challenging
technologies that needs to be developed in
moving towards realistic
haptic

displays.


References


http://www.docstoc.com/docs/2685206/Introduction
-
to
-
Computer
-
Haptics


V. Hayward, O. Astley, M.C. Hernandez, D Grant, G.
Torre, Haptic Interfaces and devices, Sensor Review,
Vol.24. 2004.


Mandayam A Srinivasan, What is Haptics?, Laboratory
for Human and Machine Haptics: The Touch Lab,
Massachusetts Institute of Technology.


L. Bonanni, J Lieberman, C Vaucelle, O Zuckerman,
TapTap: A haptic wearable for asynchronous distributed
touch therapy, Proc CHI 2006.


M Srinivasan,C. Basdogan, Haptics Display in Virtual
Environment,Computer & Graphics,Vol. 2, 1997


THANK YOU