e-nable Hand Test Rig

Transcription

1 enable Hand Test Rig P606 David chwartz, Tia Parks, hannon Barry, amantha Mason, Charles Rumfola

2 Agenda Recap Problem tatement Customer Requirements Engineering Requirements ubsystems Clamp election Controller/Processor election Display Data Analysis Motor Feasibility Data Collection Feasibility Design Drawings Bill of Materials Risk Assessment Plans for Next Phase

3 Problem tatement Current tate David chwartz developed a prototype for measuring grip strength. It functions, but lacks the amenities desired for the final design. Desired tate A functioning prototype that can be used to test different types of enable devices. Device should be able to be replicated because enable is a global and open source community. Project Goals Analyze the current accepted methods of testing grip strength. The apparatus must be: Easy to Use Portable Cost Effective Repeatable Constraints Cannot disassemble or break the hand in the process of measuring grip strength. Cost of end product should cost under $200 to produce.

4 Customer Requirements Inexpensive, $200 should be the maximum for construction Portable Repeatable Adaptable to other prosthetic models Easy to use Continuous Data Acquisition Does not alter prosthetics or remove any pieces Test the full hand strength, an overall grip strength test versus the angle of the wrist flexion

5 Engineering Requirements Requirement # Importance Metric Unit Target Value ubsystem $ 200 Entire Apparatus 9 Cost 2 6 Weight of Tester lbs 50 Entire Apparatus 3 5 Duration of Test min 5 Motor 4 8 Force Measurement Accuracy oz Load Cell and Amplifier 5 8 Angle Measurement Accuracy 2 Motor / Data Acquisition 6 9 Max Force of ensor lbs 50 Load Cell 7 8 Torque oz/in 250 Motor

6 Clamp Testing Trip to Home Depot

7 Clamp election 6 in. Medium Trigger Clamp $0.97

8 Controller / Processor election High Level Understanding of Electronics Microprocessor Processes Data Microcontroller Control Motor Arduino Controls motor and processes data Assumptions: All controllers will be compatible with our other electronics. Users will have access to a computer with Excel or will be able to download an open source program. Analysis: Based on research and analysis we have found that Arduino is compatible with Excel. It is also easy to use, controls and processes data, and is open source.

9 Display Data Analysis External LED Display D Card Computer LabVIEW Interface Graph Function Microsoft Excel PLXDAQ GoBetwino Function

10 Motor Feasibility Torque Requirements Torque requirements determined through measuring enable gauntlet length and max force exerted Due to the small sample size and uncertainty of the data, the highest value calculated was multiplied by a factor of 3 to yield our basis for holding torque _max =.79 lb*in (89 oz*in) Torque Value Max Force Gauntlet Length Calculated Torque (F*L/2) Raptor (Green) lb 2 oz 4 in 2.25 lb*in 36 oz*in Raptor (Blue) lb oz 3.4 in.8 lb*in oz*in Raptor (Black and White w/ Whippletree) lb 3 oz Name oz*in 4.33 in 3.93 lb*in

11 ervo vs. tepper Motor ervo Motor Maintains torque at high speeds Requires encoder to track position More prone to fatigue and degradation tepper Motor Higher maximum torque, but degrades faster with higher Finite number of angular positions Builtin angle sensor tepper was chosen because we do not foresee any need for the motor to move quickly, to eliminate the need for an angle sensor, and to be cost effective.

12 tepper Motor Pugh Chart tepper Online Nema 23 $24.42 Requirements 2448V, 2.83A Holding Torque 283 oz*in tep Angle.8 Pololu 477 $49.95 Requirements 8.6V,.0A Holding Torque 90 oz*in tep Angle.8 Robotshop Nema 7 $48.00 Requirements 2V,.7A Holding Torque 667 oz*in tep Angle 0.08 MPJA Nema 23 $23.95 Requirements 5.7V, 2.3A Holding Torque 222 oz*in tep Angle.8 Criteria Pololu 477 Robotshop Nema 7 MPJA Nema 23 Cost Required Voltage Holding Torque tep Angle Total Required Current tepper Online Nema 23 Datum Datum

13 tepper Motor Pugh Chart Cont. Criteria tepper Online Nema 23 Pololu Cost Required Voltage Required Current Holding Torque tep Angle Total Robotshop Datum Datum MPJA Nema 23

14 Adafruit Motor/tepper/ervo hield Can drive motors from 4.5 V3.5 V Compatible with Arduino software Tested and warrantied Price: $9.95

15 Data Collection ystems Design phase left us between these two designs: train Gauge Load Cell Finger ensors

16 Data Collection (Finger ensors vs train Gauge) Overview: Finger ensors train Gauge Load Cell Measure individual finger Measures accurate Can strength whole hand grip Measure Can tell if one finger is More portable than 5 Pinch applying more/less force sensors Grip than another Less expensive Less accurate especially Has higher force with whole hand grip range Harder to mount

17 Data Collection (Pugh Chart) FR (0.5 ) FR (0.3 ) Piezoelectric ensors train Gauge Load Cell Cost Ease of Mounting Accuracy Programmability Ease of Obtaining Force Range Total 3 Criteria Conclusion: train Gauge Load Cell is the best option Datum Datum But since FR s are cost effective and easy to use this will still be tested as a backup plan.

18 Types of Load Cells ource:

19 Load Cell (Pugh Chart) Criteria Cost Accuracy Ease of obtaining Total 3 Force Range Datum Datum Conclusion: Bar ingle Point load cell will be the best (Most accurate/cost effective) (Link)

20 Load Cell election Conclusion: Cost Effective Measures higher than needed force range Very Accurate Excellent off center loading compensation Price: $ kg ingle Point Load Cell

21 Design Isometric View

22 Design TopDown View Modular Can account for arms Can account for different grip positions

23 Bill of Materials ID Part Name Quantity Price/Unit Total Price Make/Buy Arduino Uno $24.95 $24.95 Buy 2 tepper Motor $23.95 $23.95 Buy 3 Wood Base 3 Acquire 4 Wooden Wheel $5.85 $5.85 Buy/Make 5 Clamp $0.97 $0.97 Buy 6 ensors 5 $8.95 $44.75 Buy 7 Load Cell $7.00 $7.00 Buy 8 Motor hield $9.95 $9.95 Buy 9 Wooden Dowel $6.94 $6.94 Buy 0 crews 4 Acquire Op Amp $6.43 $6.43 Buy 2 Power upply $.34 $.34 Buy $62.3 Total

24 Block Diagram

25 Risk Assessment Risk Assessment

26 Plans for Next Phase