First Progress Report

 

Artificial Hand

Academic year 2004

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NAME: D.A.M.AbeysekaraREG.NO: 69960486CENTER: Clombo

Presentation Contents

Literature Survey on Artificial Hands

Study on Hand Anatomy

Problems

Reference

Muscle Sensors

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Design of the INSTITUTE OF APPLIED COMPUTER SCIENCE RESEARCH CENTER OF KARLSRUHE, GERMANY

Design of the Oxford Orthopedic Engineering Center, Oxford University

Desiign of the state University of New Jersey

Design of the Southampton University.

Design of University of Newcastle

Design of University of Bremen

Literature Survey on Artificial Hands

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Design of the INSTITUTE OF APPLIED COMPUTER SCIENCE RESEARCH CENTER OF KARLSRUHE,

GERMANY

Low Weight

Has13 independent degrees of freedom

Uses powerful small size flexible fluidic actuator

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Design of the Oxford Orthopedic Engineering Center, Oxford University

Hand has two fingers and a thumb

Able to grasp objects in a more natural manner.

Weighing half a kilogram

can be operated by tensing two muscles in the user’s forearm

Two electrodes – one for each muscle – read the tiny electrical signals

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Design of the state University of New Jersey

Design by Rutgers biomedical engineer and inventor William Craelius(Dextra artificial hand )

Has natural control of up to five independent artificial fingers

Controlled by electrical signals generated by the user's remaining muscles and tendons

Pneumatic sensors

(inside sleeve)

Male manifold

female manifold

Pressure transducers & analog signal conditioning

Microcontroller computer

Prosthetic hand with servo actuators

Sleeve inserts in socket and manifolds connect

Servo control line

Analog digital interface

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Design of the Southampton University.

The development of a hierarchically controlled, myoelectric prosthetic hand.

At present a multiple degree of freedom device is under development

lightweight materials are used

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Design of University of Newcastle

The aim of this project was to design and develop a low cost end effectors for an artificial hand that can be used to provide versatile grasp

It has been shown that a flexible water filled toroid made of rubber can be used to pick and place soft objects of variable geometry

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Design of University of Bremen

Five-finger hand has 11 degree of freedom

Driven by flexible fluidic actuators

Different additional grasp tasks shall be programmed

Desired grasping movement is demonstrated by a human instructor using Cyber Glove

Study on Hand Anatomy

Brachialis

Pronator teres

Flexor carpi radialis

(Wrist: Flexion, Abduction )

Palmaris longus

(Wrist: Flexion )

Flexor digitorum superficialis(Digits: Flexion of fingers )

Flexor carpi ulnaris

(Wrist: Flexion and adduction )

Major Superficial Muscles:Anterior Forearm

Major Superficial Muscles:Posterior Forearm

Brachioradialis

Extensor carpi radialis longus

(Wrist: Extension and Radial deviation )

Extensor carpi radialis brevis(Wrist: Extension and

Radial deviation)

Anconeus (cubitalis rolani)

Extensor carpi ulnaris(Wrist: Extension and adduction (ulnar deviation) )

Extensor digiti minimi(Digits: Extension of little finger )

Extensor digitorum(Digits: Extension of fingers )

Flexor carpi ulnaris(Wrist: Flexion and adduction )

Abductor pollicis longus(Digits: Abduction of thumb )

Extensor pollicis brevis

(Digits: Extension of thumb )

Radial

Cross Section of the human hand

Sensors used for detect the muscle movement

Sensing method 

Most of the designed Artificial Hands use Myoelectric technology for sensing the amputees muscle movements.

“myo” is the ancient Greek name for Muscles. The technology used for convert the muscle movement into electrical signal is known as Myoelectric technology .

Four type of sensors can be used as a Myoelectric sensor.

Pressure sensors

Strain Sensors

Nerve Sensors

EMG SensorsHome

Pressure sensors

Graduate student Mike Kogan’s idea was to embed the soft, air-filled bladders directly into the silicone sleeve, and he devised a way to do that when the sleeve gets custom molded to fit an amputee’s residual arm. The tubes from the bladders lead to commercially available sensors that actually measure the air pressure that correlates with muscle movement. Not only are the pneumatic devices comfortable.

Pressure sensors are used as a muscle movement sensor in the project of the DEXTRA Artificial Hand project.

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Strain Sensors

The skin is stretch according to the muscle movement of the amputees’ upper limb. Then sensing this stretch of the skin, muscle movement can be identified. Hence in this project this stretch of skin is going to sense using foil strain sensors. The typical foil strain sensor, which can be use for this purpose is shown below.

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Nerve Sensors

There are three common types of microelectrodes:

Array-type

Probe-type

Regeneration electrodes

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These types of chemical sensors still aren't perfectAs microelectrodes can be very hard to use. For the Array microelectrodes, appropriate cell culture methods have to be used and practiced for the information to be gathered properly. Probe types have to be placed on amplifier boards, and since two experiments are never the same, each situation would require various different sized/shaped probes. Regeneration electrodes have to be attached to the stumps of the nerve trunk, and require connecting to the outside world.

Nevertheless, if all these devices are used in the proper manner, huge amounts of data can be collected.

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EMG Sensors

EMG Stands for Electromyography.

Specially design for sense the muscle movement.

Ag_AgCl electrode are used as a EMG sensors.

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THANK YOU FOR YOUR ATTENTION

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