Status Report for ME 470 Senior Design Team #99

ME 470 : Myoelectric HandFinal PresentationUniversity of Illinois at Urbana-ChampaignInnovation Trophy Team

Patrick Chwalek Kyle Mitchell Jack Moore Patrick Slade Faculty Advisor: Dr. Yuhang Hu

TA: Conrad SmithPresented on:December 8th, 2015

PSYONIC2

Patrick Slade

Research based startup out of the Bretl Research Group in UIUC. Cofounded by myself and a graduate student, Aadeel Akhtar. Want to develop low-cost myoelectric devices for the entire world.

Startup from the Bretl Research GroupDeveloping advanced myoelectric prostheses for the entire worldCozad New Venture Competition and Samsung Innovation winners

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Current Solutions3

11.4 million hand amputees world-widePatrick Slade

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Myoelectric System4

Patrick Slade

ElectrodesEMG ElectronicsMyoelectric HandSocket

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Project Goals5

Jack MooreDeliverableSpecificationsFinger force3-16 newtonsFinger speed90 degrees/secondFinger Range90 degreesHand WeightUnder 500 gramsHand sizeMedian male sizeCompliant fingersN/ACost to produce$1,000

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Competition6

Patrick Slade

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Final Design7

Patrick Slade

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Finger Module8

Patrick Slade

Solid Finger DesignMore robustSimpler assembly and repair processEasily integrate flexible materials and sensors

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Functional Testing

Jack MooreMotorVoltage (V)No-Load Current (mA)No-Load Speed (deg/s)Stall Force (N)Stall Current (mA)Weight (g)Length (mm)Cost ($)Pololu66039.33.36009.52616Maxon612038.93.75102954.9140Maxon4.510019.23.03902954.9140i-limb6NA60.53.09-6.249191852200

9Purchased Pololu and Maxon motorsMost important tests: finger speed and forcePololu motors used in final product

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Compliant FingersShock absorberTest different rubbersAdd pressure sensors

Jack Moore

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Thumb DesignWeight and size: average male handSmall hand leads to difficult thumb designTwo motors needed for thumb moduleFinal weight: 381 grams (0.85 pounds)

Jack Moore

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Add another picture of previous design.11

Current Thumb Design12

Patrick Chwalek12

Here you can see our current thumb design. So in the past iterations that you have already seen, our approach was initially to design for a small form factor and then try to make it robust but with this design, we reversed those two. We made it initially robust and large, while later focusing on mounting the thumb strategically to reduce the amount that the housing protrudes. 12

Current Thumb Design (cont.)13

Patrick Chwalek13Motor AssemblyBack CasingWormWormWorm GearWorm GearPinBearingsPinBearingOpening for Cables

So here is a cross sectional view of the thumb assembly. So the top half is composed of the motor assembly, similar to that seen in the motor modules for the other four fingers. The only difference is the form factor of the housing since it has to connect with a second motor housing located below in order to allow for abduction. Both motor housings will be linked together with a mounting mechanism, similar to that of a door hinge. We chose this type of attachment because it was our most robust iteration. 13

Assembly Design14

Patrick Chwalek14

And in this view you see how the thumb, as well as all the other fingers, are incorporated into the overall design of the hand. The back hand housing was designed in such a way that the thumb attachment would rest lower then the other 4 motor modules, minimizing thumb housing protrusion.

Update photo14

Back Hand Housing15

Patrick Chwalek15

The housing has several features that allow us to make the hand as thin as possible with our current design. We have five divots located in the design to allow for the motor modules to sit as close to the back plate as possible. The back hand housing also has support structures that hold the motor modules in place, as well as leave room for the PCB to be mounted.15

Manufacturing Costs(Estimated using aPriori)1000 Batch Hand - Roto & Blow MoldingPartQuantityMaterialManufacturing SiteFully Burdened Cost (FBC)Quantity per HandFBC per HandPalm Back1000ABSUSA$20.731$20.73Finger4000ABSUSA$3.154$12.60Palm Front1000ABSUSA$7.851$7.85Motor Housing4000ABSUSA$2.414$9.64Thumb Upper Housing1000ABSUSA$15.101$15.10Thumb Bottom Housing1000ABSUSA$8.821$8.82Thumb1000ABSUSA$11.261$11.26Back Casing1000ABSUSA$7.071$7.07Price per Hand:$93.07

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Patrick Chwalek16

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Total Cost(Batch of 1000)ItemPart NumbersCompanyQuantityPrice Per Hand Total Price Motor/Gearbox2381Pololu6$12.71$76.26WormWFS-3SWM Berg6$48.14$288.84Worm GearWFB83-S30WM Berg6$16.71$100.26Teensy 3.1TEENSY31PJRC2$19.80$39.60Pair of Encoders2598Pololu3$6.95$20.85Dual Motor Drivers713Pololu3$3.49$10.47Bearings (3mm)LFM-0304-03Igus12$0.48$5.76Bearings (5mm)LFM-0507-04Igus6$0.54$3.24Screws and NutsmultipleMcMaster-Carr1$8.75$8.75Hand PCBN/AOSH Park1$9.13$9.13EMG BoardN/AN/A1$100.00$100.00Battery/ChargerN/AN/A1$60.00$60.00Manufactured ComponentsN/AN/A1$93.07$93.07Total Hand Cost:$816.23notes: -Price does not include labor costs for assembly and shipping of subcomponents-EMG Board and Battery/Charger combination costs is an estimate

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Patrick Chwalek17

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Patrick Chwalek

18ComponentPart Number(s)VendorPriceQuantityTotalInvoice TotalComponentsMotor/Gearbox2381Pololu$16.958$135.60$202.10Pair of Encoders2598Pololu$8.954$35.80Dual Motor Drivers713Pololu$4.955$24.75WormWFS-3SWM Berg$48.148$385.12$647.52Worm GearWFB83-S30WM Berg$17.308$138.40Teensy 3.1 w/ PinsTEENSY31_PINSPJRC$22.802$45.60$72.57Teensy 3.1 w/o PinsTEENSY31PJRC$19.801$19.80Motor with Gearbox265389 & 110315Maxon$124.886$749.28$698.33Bearings (3mm)LFM-0304-03Igus$0.9814$13.72$48.26Bearings (5mm)LFM-0507-04Igus$1.0520$21.00Drive Shaft (3mm)1265K33McMaster-Carr$24.481$24.48$54.32Drive Shaft (5mm)1265K47McMaster-Carr$29.831$29.83M1.6 Screws (5mm)91430A005McMaster-Carr$10.451$10.45$38.94M1.6 Nuts90591A109McMaster-Carr$8.511$8.51M2 Dowel Pins93600A076McMaster-Carr$7.701$7.70M2 Screws (5mm)91801A106McMaster-Carr$5.021$5.02M2 Screws (8mm - Phillips)91801A109McMaster-Carr$5.181$5.18M2 Nuts90591A265McMaster-Carr$2.081$2.08M2 Screws (8mm - Flat Head)91430A005McMaster-Carr$6.921$6.92$28.39M2 Screws (12mm)90591A109McMaster-Carr$7.581$7.581/2" Steel Cap Screw93600A076McMaster-Carr$6.241$6.241/2" Nut91801A106McMaster-Carr$7.651$7.65Custom PCBOSH Park$9.133$27.40$27.40Component Total: $1,817.83FacilityPredicted Cost Labor Machine Shop$118.00Ford Lab$135.72Labor Total:$253.72kkkTotal Project Cost:$2,071.55Total Budget:$2,400.00

-budget of $2000 from MechSE-includes extra parts-limited by lead time-ordering inexpensive set of motors for design

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Electronics

Kyle MitchellTeensy 3.1 microcontrollerPolulu motor controllers6 motors/encodersPrinted circuit board

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20Electronics (Cont.)

Kyle Mitchell

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21Code Features

Kyle MitchellDeveloped in Arduino IDEInitialization Communication protocolSerial PID controlStall positions

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PID Control

Kyle Mitchell

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Low cost : total cost under $1000 per hand$816 per handLightweight: weight under 500 grams381 gramsMeets or exceeds performance specifications of commercially available systemsDurablePowered thumbNeural control

23Kyle MitchellSummary23

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26AcknowledgementsMechSE Innovation Trophy CompetitionProf. Yuhang HuConrad SmithPSYONIC

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