PowerPoint Presentation

A Six Degree of Freedom Open Source Hand for Evaluating Myoelectric ControlNili E. Krausz 1,2 , Ron A.L. Rorrer 1, and Richard F. ff. Weir 3

1Dept. of Biomedical Engineering, Northwestern University 2Dept. of Mechanical Engineering, University of Colorado Denver 3Dept. of Bioengineering, University of Colorado Denver

ObjectiveDesign and fabricate an inexpensive rapid prototype hand that could be used to test and validate the effectiveness of control and intent recognition methods using a physical prosthesis, rather than a virtual hand.

GoalsStandard prehensile patterns

Independent fingers and thumb

Total cost less than $2000

Anthropomorphic size and weight

Open source

Design

Gen. 1Gen. 3Gen. 2

Design

SAY SOMETHING ABOUT RAPID PROTOTYPINGFinger Design

Proximal Finger ShellDistal Finger ShellProximal shaftMiddle shaftDistal shaftFinger MotorEach finger utilizes a 1724 Faulhaber motor, and after gearing this yields 56 N grip force at the fingertips.

Finger Flex/Ext

Thumb Design

Thumb ShellThumb BaseFlex/Extension shaftFlex/Extension motorRotationaxisFlex/extension uses a 1516 Faulhaber motor, and this is equal to 4.5 N at the tip of the thumb.

Rotation 1016 motor yields 0.23 N-m of torque for the thumb rotation.

Thumb Flex/Extension

Thumb Rotation

Palmar PrehensionLateral PrehensionTip PrehensionPrehension Postures

99th percentile male50th percentile male50th percentile femaleAnthropometrics1 cm1 cmHand Height20 cmHand Breadth10 cmWrist Breadth5 cmWrist Circumference14.7 cmHand Circumference (metacarpals)22 cmHand Thickness (metacarpals)2.4 cmHand Thickness (thenar pad)6 cm

Compared to values from Garrett [16] and Tilley [17])

PrototypeTotal cost is $2200.High torque motors and gearheads are $1680.

Prototype weighs 584 g

50th percentile male hand

All CAD files and relevant details will be uploaded to www.opensourcehand.wordpress.com

ConclusionsDesigned and fabricated a 6 DOF rapid prototyped hand that: Can produce standard prehensile patterns.Has independently actuated fingers and thumb.Is inexpensive, with total cost of $2200.Is within the size and weight of anatomical hands.Is open source.

Hand Improvements:Decrease the overall size and weight of the hand.Increase strength of the thumb flexion/extension mechanism.Consider metal fabrication for improved durability.Development of open source control hardware and software for controls testing.Mechanical tests to compare the hand to other multi-DOF hands.Future Work

AcknowledgementsUC Denver Center for Faculty DevelopmentDenver VMAC- VA Eastern Colorado Health Care SystemNSF GK-12 Transforming Experiences GrantUC Denver Dept. of Mechanical EngineeringNorthwestern University Graduate Travel GrantUC Denver CEAS Machine ShopBiomechatronics Development Laboratory Childrens Hospital ColoradoCenter for Bionic Medicine

16Questions??All CAD files, part numbers, fabrication and assembly instructions, and other information regarding the hand will be uploaded and freely shared at www.opensourcehand.wordpress.com

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