Athanasios Vourdoumpas

BaiLiang Chen

Xueni Pan

Haptic Interfaces

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Overview

PART 1 Introduction Reasons Components Properties

PART 2 Methods and Applications

PART 3 Comparison Conclusion

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Introduction

What is touch? Tactile sense Texture Vibration Temperature Small-scale shape or

pressure distribution Wetness, etc

Kinesthesia/Proprioception Size Shape Weight Position in space/rotation

“The cutaneous system provides a map of space within reach of the body”. (Klatzky, R. L., & Lederman, S. J. (2002). Touch.)

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Where do we sense touch?

Tactile feedback sensors are close to the skin. Density varies. They sense initial contact.

Kinesthetic/Force feedback is sensed deeper in the body such as in muscle tendons, bones and joints.

Proprioceptive sensing takes place in joints as well as the inner ear and central nervous system. Proprioceptive senses a person’s position and movement.

Values for the two-pointDiscrimination threshold at different regions of the hand

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What is Haptics and Haptic Interfaces?

Haptics means interaction with both tactile and kinesthetic feedback.

Haptic interfaces (HI) enable person-machine communication through touch.

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…which means:

Making use of force, movement & other

stimuli: To convey force To convey movement of objects To convey realism of objects:

Give them physical rigidity To give them surface properties Give them resistance Give them weight

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Why a Haptic Interface?

Up until now, most human – computer interaction is one way.

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Why a Haptic Interface?

Haptic devices are input-output devices(Bi-directional).

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Why a Haptic Interface?

The sense of touch can carry huge amount of information

To be able to actively interact with an environment, there

must be feedback.

It increases sense of presence in a VE application

It increases human performance

It can be fun!

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Until now…• History of Haptic Systems Development 1964: First Exoskeleton device 1967: GROPE (University of North Carolina) – 1990 :

GROPE III 1976: Tele-Robotics, Teleoperation (for remote

manipulation of toxic or radioactive materials) 1994: Appearance of commercial haptic devices

(Immersion, SensAble) +1995: Many research activities in the area haptic device

and application development +2000: Many devices available (research and commercial)

for specialized applications

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ExamplesAh, pictures at last!

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Examples

And many many more…

..and more pictures!

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Ultimate Goal

• Ivan E. Sutherland (1965)

“The ultimate display would, of course, be a room within which the

computer can control the existence of matter. A chair displayed in such

a room would be good enough to sit in. Handcuffs displayed in such a

room would be confining, and a bullet displayed in such a room would

be fatal. With appropriate programming such a display could literally

be the Wonderland into which Alice walked.”

But for now we must use machines…

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Haptic Human Computer Interaction

(Figure by C. Hui, S. Hanqiu)

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HI basic components

Motor and transmission to send physical stimulation

Electronics to control sensors and motor

Software equations and algorithms for creating real world physics

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Problems

• Human sense organs are extremely sensitive cover the hole body can sense different properties of the environment

Requires usage of high precision machinery Very high update rate (with a maximum over 1kHz) Huge number of individual stimuli, that vary in properties of effect

(a tactile display needs more than 1000 stimulator elements for the hand) Usually of great size High precision sensors and trackers Powerful computational devices Extremely expensive

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What is enough

“As long as certain minimum levels of force and stiffness are met,significant variations in the fidelity of the haptic simulations appear

to have little effect on the subjects’ ability to identify and discriminatebetween simulated objects.” (G. Upperman and M. O’Malley. “A Study of Performance

in Haptic Environments: How much fidelity is enough?” July 2003).

Of course, that depends on the application.

The user can quickly adapt to the device

Combined with other interfaces( e.g. visual) it can create adequate feel of presence

Being "suggestive" is what matters the most.

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Characteristics of a HI Tactile or/and Kinesthetic feedback

Force magnitude (continuing / peak) Number and type of individual stimuli (actuators)

Tracking / Feedback resolution Number of degrees of freedom (DOF) Time lag and update rates for position sensing and

force control (refresh rate 1kHz) Workspace Device properties(friction, inertia, stiffness etc) Collaboration with other types of virtual interface Force reference system (Ground-, Body- or Un-Based) SAFETY!

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Classification

Space 2d 3d

Reference system Ground/Desktop Based Body Based Un – Based

Feedback Tactile Kinesthetic

Actuators Electrostatic Electromechanical(Piezoelectric, Motor,

SMA , micro-coil ) Rheological Fluid Air jet Thermal Hydraulic Electrocutaneous Pneumatic Magnetic Gyroscopic Other

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Body-based HI

Force-feedback glove 5 degree of freedom 16N to each

fingertips Pneumatic pistons

Rutgers Master II-NDRutgers University

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Pneumatic pistons

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Pistons

Pneumatic air

hydraulic fluid Rheological fluid with electro-magnetical

properties

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5 degree of freedom

Each actuator is attached to the base through a spherical joint (2 DOF)

Its cylinder shaft can both translate and rotate(2 DOF)

The fingertip attachment connects to the cylinder shaft through a cylindrical joint(1 DOF)

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Rutgers Master II-ND

Low weight portable device to simulate the grasping

of virtual objects Designed for dexterous interaction with

virtual environments.

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Ground (desk)-based HI

Ground based HI are

those that have a stable

point in the environment

(ground or desktop)

as a force reference

FEELEXUniversity of Tsukuba

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Exoskeleton device – Master arm

Southern Methodist UniversityPneumatic Haptic Interface

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Exoskeleton device

simulation of the driving experience for

cockpit design optimization

PERCRO Laboratory

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Ground-based HI

Highlighted Features:

Six degree-of-freedom positional sensing

Portable Automatic

workspace calibration

PHANTOM® Desktop™

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Price of the Phantom®

http://www.kaemart.it/touch-and-design/

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2DOF Haptic Devices Provide the feeling of

real touch High fidelity(400Hz) rehabilitation of

visually handicapped persons, micro-gravity experiments

Ground-based HI

PantographMcGill University

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3 DOF force-controlled Provides the user with a

crisp haptic sensation and the power to closely simulate the weight and force found in a wide variety of human tasks

Ground-based HI

HapticMASTER © FCS Control Systems

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Reference

Haptic Interfaces and Devices Vincent Haward, Oliver R Astley, Manuel Cruz-Hernandez, Danny Grant, Gabriel Robles-De-La-Torre

The Rutgers Master II-ND Force Feedback Glove1 Mourad Bouzit, George Popescu, Grigore Burdea and Rares Boian Center for Advanced Information Processing

HW AND SW TECHNOLOGY AND COGNITIVE ERGONOMICS UPDATE By Monica Bordegoni (Politecnico di Milano)

Master arms Mechanical Engineering Department, SMU

Project FEELEX: Adding Haptic Surface to Graphics,Proceeding of SIGGRAPH2001(2001) Hiroo Iwata, Hiroaki Yano, Fumitaka Nakaizumi, Ryo Kawamura

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How --- for a better simulation

Touch the virtual reality

You need response

Feed-back mechanism

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Feedback Mechanisms - Actuators

Can be electrical or mechanical

Magnetic actuators

Light electrical shocks

Direct-Current Motors

Hydraulic actuators – have high maintenance

Pneumatic actuators use compressed air

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Comparation

Technology Description Advantage Disadvantage/

Electrical

Mechanisms

Electrical Mechanical Motors

easy to implementtool to touch objects Provides

Low band-widthUnsuitable

Electrostatic Composed of a polymeric elastic dielectric that is

sandwiched between compliant electrodes

Flexiblea high energy densityMaterials are low costSuitable for large skin areatelemanipulation

Safety problemLack of related knowledge

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Pneumatics A gas is pressurized by a power plant controlled by servo-values, and delivered to rotary or linear actuators through pressurized fluid (air) lines

Good static force capabilityLighter than hydraulicsEasier than hydraulics

Relative low bandwidthLow actuation stiffnessLow power capacity

Rheological/ Hydraulics Fluid

By the change from a state of liquid to a state of solid or near-solid

Low energy consumption Simple mechanical design Active touch.Small sizeBe able to connect with other technologies

Problems—related

to other area problemsOver heatingSafety problem because of high voltage

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Where to use?

Several examples Proceedings of the 2003 Conference on New Interfaces for Musical

Expression (NIME-03), Montreal, Canada New CAD maxim: Two hands are better than one

virtual reality training main area

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Application Area

Force-reflecting input devices for use with graphical user interfaces Games. Multi-Media Publishing Arts and Creation Editing sounds and images Vehicle operation and control rooms Engineering&ManufacturingTelerobotics and teleoperation Education and training Scientific Study of Touch.Medical Use

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Conclusion

Trade-off: due to different areashuman sensory-motor skills improve communication between humans and machines.Linking device performance to human performancethe more systematic study of the connection between devices and specific tasks and applications

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Future– discussion with you!