First Progress Report Artificial Hand Academic year 2004 Department of Electrical and Computer Engineering Faculty of Engineering Technology The Open University of Sri Lanka NAME: D.A.M.Abeysekara REG.NO: CENTER: Clombo

Presentation Contents Literature Survey on Artificial Hands Study on Hand Anatomy Problems Reference Muscle Sensors Home

 Design of the INSTITUTE OF APPLIED COMPUTER SCIENCE RESEARCH CENTER OF KARLSRUHE, GERMANYINSTITUTE OF APPLIED COMPUTER SCIENCE RESEARCH CENTER OF KARLSRUHE  Design of the Oxford Orthopedic Engineering Center, Oxford University Oxford University  Desiign of the state University of New Jersey University of New Jersey  Design of the Southampton University.Southampton University.  Design of University of NewcastleUniversity of Newcastle  Design of University of BremenUniversity of Bremen Literature Survey on Artificial Hands

Home 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

Home 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

Home 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 Microcontroll er computer Prosthetic hand with servo actuators Sleeve inserts in socket and manifolds connect Servo control line Analog digital interface

Home 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

Home 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

Home 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 Sensors Home

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.DEXTRA Artificial Hand Home

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. Home

Nerve Sensors There are three common types of microelectrodes:  Array-type  Probe-type  Regeneration electrodes Home

 These types of chemical sensors still aren't perfect  As 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. Home

EMG Sensors  EMG Stands for Electromyography.  Specially design for sense the muscle movement.  Ag_AgCl electrode are used as a EMG sensors. Home

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