120215 pediatric prosthetic arm
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Transcript of 120215 pediatric prosthetic arm
Pediatric Prosthetic Arm
Group 17Nabeel Chowdhury, Seul Ah Kim, Dah Som Kim
• Children need a prosthesis from an early age to develop motor skills and so that a device will integrate into their social identity
• Currently the market is saturated with upper limb prosthetics aimed at adults.
• The majority of prosthetics that children have access to have little functionality
The Need
• We aim to make an affirdable lightweight, durable, and waterproof myoelectric transradial prosthetic actuated by a mckibben air muscle.
• This project aims to deliver a proof of concept of the air muscle
Scope
Design Specifications
Overview of design-Air Muscle Diagram
• Mckibben, the inventor of the muscle, used this as an orthotic allowing for a pinch grip
• The shadow arm uses air muscles to make a highly dexterous hand
• Vanderbilt used pneumatics to make a fully gas powered trans-humeral prosthetic
Feasibility-use of pneumatics
http://edge.rit.edu/edge/P14253/public/Additional%20research/Shadow%20hand%20HQ/shadow_robot_company_hand_c5_claw_back.jpg
• Our batteries have a capacity of 180mAh and the average consumption is 150mA.
• Assuming average current consumption is 10% maximum and 90% rest,
• This is much lower than our specifications and means we will either need a larger battery or a method that uses less power.
Feasibility-Battery Life
• Design specification ME03: total weight of the prosthetic arm should not exceed 2.5 kg.
• Total weight = weights of the casing and internal components. • The casing, which includes hand, lower arm, and socket, weighs
212.5g in total. • The internal components, including solenoid valve, wires, microchips,
air muscle, and metal adaptors weighs 489.92g in total.
• Note that human hand weighs about 400g, and our hand weighs less than 212.5g.
Feasibility-Weight
• The prosthetic exhibited ability to contract farther with greater weights.
• This appears to be a distinct characteristic of air muscles which is similar to the way a real muscle would behave
• The amount of mass the air muscle could pull is well above our specification.
Feasibility-Strength
Specifics-Casing
Specifics-Hand
Specifics of design-Circuit Diagram
Specifics of design-Program Flowchart
Specifics of design-Solenoid
http://www.solenoidsolutionsinc.com/images/threeWay.gif
Specifics-Air Muscle
• The prosthetic can pull a large amount of mass meaning it has a large grip force
• The parts of the device are easy to remove and exchange
• The device is water resistant in heavy rain
Conclusion-Successes
• The device is heavier than the previous version
• The device is not fully waterproof
• The socket will come off after a drop, but the device doesn’t break pro and a con
• The adaptor with all of the brass fittings was too long to fit inside the device, but it would fit if the patient grew.
Conclusion-Failures
• Custom machining the brass fittings out of aluminum• reduces weight and length
• Smaller/Refillable CO2• Internal Charging for batteries• Using a servo valve
• reduces weight, size, and power consumption• Using a pressure regulator
• eliminates the need for a needle valve• Brushing on epoxy to the surface of the 3D print or sealing the casing with a stronger rubber than hot
glue.• seals all of the layers of the print
• Using inductive charging• the qi standard allows for a universal charger and it is waterproof
• Using solar power to keep the battery alive longer
Future Directions
Budget
Design Specifications
Questions?
Prototype Demonstrations-Video
Prototype Demonstration-Length Change
Prototype Demonstration-Casing and Wrist