GRASP REDESIGN STANFORD

1. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Redesign of Free Force Sensor Pinching Unit : GRASP VA Rehabilitation Research & Development Center, Palo Alto July-August 2005

2. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Project Team IIT Kanpur VA Rehabilitation Research & Development Center Aakash Kumar Ruchin Chaudhary Niels Smaby Mary Elise Johanson Wendy Marie Murray Eric Topp Deborah Ellen Kenney Stanford University Maurice Leblanc

5. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Project Brief System Objectives System Schematics System Analysis Need Statement Specifications & Constraints Primary Product Requirement Ergonomic Analysis Analysis of Existing Design References and Literature Concept Generation Discussions/Interactions Physical mock-ups, Prototypes Preliminary User Testing & Analysis Detailing and validation Final Prototype Final Prototype Analysis Discussion Future Scope* Project Methodology: Schedule 22nd June 29th June 1st July 4th-20th July 20th July 26th July 27th July- 11th August 16th August

6. Pinching Unit Redesign – VA Rehabilitation Research & Development Center • Tetraplegics have restricted limb movements • The tendon transfer surgery for hand can be helpful,it assist them to apply forces through thumb and index finger* • Reconstructive hand surgery enables the “key-pinch” in the subjects • Research is oriented towards these pinch force measurements *Journal of Rehabilitation Research and Development,Mar-Apr 2004 , Niels Smaby, MS; Mary Elise Johanson, MS, PT; Brian Baker, BA; Deborah Ellen Kenney, MS, OTR;Wendy Marie Murray, MS, PhD; Vincent Rod Hentz, MD System Objectives- Medical Application Schematics for surgery and functioning

10. Pinching Unit Redesign – VA Rehabilitation Research & Development Center The product is an assistive device to a study that aims to establish target pinch forces for completing selected tasks that represent a range of useful functional activities in daily life*. • Opening and closing two types of zippers • Inserting and removing a plug • Inserting and removing a key • Inserting and removing an ATM card • Stabbing “food” with a fork • Using a remote control button *Journal of Rehabilitation Research and Development,Mar-Apr 2004 , Niels Smaby, MS; Mary Elise Johanson, MS, PT; Brian Baker, BA; Deborah Ellen Kenney, MS, OTR;Wendy Marie Murray, MS, PhD; Vincent Rod Hentz, MD System Objectives- Bio-Medical Research

11. Pinching Unit Redesign – VA Rehabilitation Research & Development Center The product is an assistive device to a study that aims to establish target pinch forces for completing selected tasks that represent a range of useful functional activities in daily life*. • Opening and closing two types of zippers • Inserting and removing a plug • Inserting and removing a key • Inserting and removing an ATM card • Stabbing “food” with a fork • Using a remote control button *Journal of Rehabilitation Research and Development,Mar-Apr 2004 , Niels Smaby, MS; Mary Elise Johanson, MS, PT; Brian Baker, BA; Deborah Ellen Kenney, MS, OTR;Wendy Marie Murray, MS, PhD; Vincent Rod Hentz, MD System Objectives- Bio-Medical Research Activities of daily living (ADLs)

18. Pinching Unit Redesign – VA Rehabilitation Research & Development Center “The pinching unit or the GRASP is the clinical testing simulator of ADLs (activities of daily livings) tasks with variable openings and lateral adjustments for different individuals” System Objectives- Product Application

19. Pinching Unit Redesign – VA Rehabilitation Research & Development Center System Schematics : Lateral pinch testing

20. Pinching Unit Redesign – VA Rehabilitation Research & Development Center “To re-design a comfortable* physical interface for a lateral pinch testing medical equipment” * Comfortable to both, the Subject and to the Clinician Re-Design Need Statement

21. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Quantitative 1) Must be adjustable vertically from 14mm to 40mm 2) Should weigh less than 100gms 3) Must accommodate FF Sensor -Dimension Ø 40mm, Ht: 12.25mm/ Dimension Ø 17mm, Ht: 14.50mm Qualitative 4) Must maintain a comfortable lateral pinch posture 5) Should be secured properly to the hand 6) Must have quick lateral adjustment 7) Must accommodate a thumb lateral angular calibration 8) Should interface with the micro scribe Specifications and Constraints

22. Pinching Unit Redesign – VA Rehabilitation Research & Development Center a) Vertical adjustment: 14-40mm b) Lateral pinch posture with hand securement c) Quick lateral adjustment (proximal-distal adjustment) d) Thumb orientation Calibration e) Space orientation measurement Keeping the comfort of the users (Subjects as well as Clinicians) into account Primary requirements

23. Pinching Unit Redesign – VA Rehabilitation Research & Development Center a) Vertical adjustment: 14-40mm b) Lateral pinch posture with hand securement c) Quick lateral adjustment (proximal-distal adjustment) d) Thumb orientation Calibration e) Space orientation measurement Keeping the comfort of the users (Subjects as well as Clinicians) into account Primary requirements X

28. Pinching Unit Redesign – VA Rehabilitation Research & Development Center • 5%ile and 95%ile fingers and thumb data (male/female) • Reach of the thumb and fingers (5-95-M-F) • Comfortable grips and postures* • Restricted and unrestricted thumb-finger movements *Strength Data for Design Safety, Product Safety and Testing Group, Institute for Occupational Ergonomics and Division of Manufacturing Engineering and Operations Management,University of Nottingham, University Park, Nottingham NG7 2RD Ergonomics Analysis Hand Anthropometrics

29. Pinching Unit Redesign – VA Rehabilitation Research & Development Center a) Vertical adjustment • Minimum 3mm required distance is not achievable (sensor limitation) • Additional caps for height adjustment –Time consuming and complex(Management of additional elements required) • Cap’s vertical wall obstruct the thumb for reaching the Sensor Existing Design: Analysis w.r.t. primary requirements

32. Pinching Unit Redesign – VA Rehabilitation Research & Development Center b) Lateral pinch posture with hand securement • Strap forcefully affects the pinching direction • Obstructs with the sensor as well as the hand at different positions • Grip??? Is it required? • Grip angle and girth might not cater to the entire population Existing Design: Analysis w.r.t. primary requirements

36. Pinching Unit Redesign – VA Rehabilitation Research & Development Center c) Quick lateral adjustment (proximal-distal adjustment) • The current distance adjustment is 11mm, required is 20mm(5-95%ile data) • Current adjustment requires screws and dismantling entire pinching assembly- takes time • Is it really required or can ergonomics can take care of it? Existing Design: Analysis w.r.t. primary requirements Proximal-Distal adjustment in existing design

37. Pinching Unit Redesign – VA Rehabilitation Research & Development Center c) Quick lateral adjustment (proximal-distal adjustment) • The current distance adjustment is 11mm, required is 20mm(5-95%ile data) • Current adjustment requires screws and dismantling entire pinching assembly- takes time • Is it really required or can ergonomics can take care of it? Existing Design: Analysis w.r.t. primary requirements Proximal-Distal adjustment in existing design & assembly system

38. Pinching Unit Redesign – VA Rehabilitation Research & Development Center c) Quick lateral adjustment (proximal-distal adjustment) • The current distance adjustment is 11mm, required is 20mm(5-95%ile data) • Current adjustment requires screws and dismantling entire pinching assembly- takes time • Is it really required or can ergonomics can take care of it? Existing Design: Analysis w.r.t. primary requirements Proximal-Distal adjustment in existing design & hand’s natural calibration

39. Pinching Unit Redesign – VA Rehabilitation Research & Development Center d) Thumb orientation measurement • Transparent protractor printed on OHP sheet. • Redesign needs to accommodate the calibration within the product e) Space orientation measurement • Design must mate with existing micro scribe for calibration Existing Design: Analysis w.r.t. primary requirements

42. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 1 Modified Existing-1 • With Ergonomic Grip design • Micro scribe attachment in grip • To be strapped to the fingers • With caps • Existing modified-mates with the current handle • Handle can be rotated for better fit

43. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 2 Modified Existing-2 • With Ergonomic Grip design • Micro scribe attachment in grip • To be strapped to the fingers • With caps • Existing modified-mates with the current handle • Thumb contours for maximum reach

44. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 3 Telescopic tube grip less • Without Grip design • Micro scribe attachment in front tube • To be strapped to the fingers • With telescopic shaft • Close to the ADLs situation

45. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 4 Grip less strap design • Without Grip design • Micro scribe attachment in platform • To be strapped to the fingers • With caps • Close to the ADLs situation • Natural calibration

46. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 5 Grip less snap design • Without Grip design • Micro scribe attachment in platform sides • To be tight-snapped to the fingers • With caps • Close to the ADLs situation • Natural calibration

47. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 6 Grip less ring design • Without Grip design • Micro scribe attachment in platform-front • To be worn on the fingers • With caps • Close to the ADLs situation • Natural calibration

48. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 7 Thumb Grip design • Without Grip design • Micro scribe attachment in platform-front • To be strapped to the wrist • With caps • Close to the ADLs situation • Natural calibration • Additional stability around thumb

49. Pinching Unit Redesign – VA Rehabilitation Research & Development Center With grip and without grip issue Already a lot of patients have been tested “with grip” pre-operatively, thus a change in the entire system would not be desirable right now. So the primary design would focus on the ‘with grip design’. And the team can possibly explore the other concepts for future scope. Necessary improvements in the discussed concepts: 1) Fillets for avoiding thumb hitting the edges 2) Hand Grip adjustment 3) Tactile improvements for the grip surface 4) Strap section to act like a grip in itself(preferable) 5) Attach straps to the grip less and test it for functionality Chosen Concepts for further detailing: 2, 4, 7 1st Discussions/Iterations/Clinician’s Interaction - 7/20/2005

50. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 2 • With Grip design • Micro scribe attachment in grip • To be strapped to the fingers • Thumb profile contours at top • With caps • Existing modified-mates with the current handle Prototyping/Physical Mock-ups

51. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 4 • Grip-less design • Micro scribe attachment • Finger guide • To be strapped to the fingers • With Caps/Without caps Prototyping/Physical Mock-ups

52. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Concept 7 • Grip-less design • Micro scribe attachment in front • To be strapped to the wrist • Cushioning at the hand interaction with device • With caps Prototyping/Physical Mock-ups

53. Pinching Unit Redesign – VA Rehabilitation Research & Development Center • Number of subjects-2 (1male,1female) • Extreme cases-one close to maximum and other minimum • Mixed reactions to the prototypes • Contour ergonomics felt comfortable to the subjects in all the cases better than the existing • Strapping needs to be stabilize and to be in soft Velcro (clinician’s suggestion) Preliminary User testing and analysis 07/26/2005-SCI Lab. VAPAHCS User testing at SCI Lab

54. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Primary requirements Concept 4 Concept 7 Concept 2 Vertical adjustment 14-40mm (closest to ADLs) 14-40mm (close to ADLs) 14-40mm (with grip) Lateral pinch posture with hand securement Unstable. Movement with straps. Secured to forefingers Stable. Slight movement with strap. Secured at wrist and thumb Stable. No movement. Secured to forefingers and palm Quick lateral adjustment (proximal-distal adjustment) Not required Not required. Can be incorporated Required Thumb orientation measurement On the platform chassis On the platform chassis On the platform chassis Space orientation measurement Mate with micro-scribe (in front) Mate with micro-scribe (in front) Mate with micro-scribe (in grip) User’s Opinion (subjects) Fair Good Good User’s Opinion (Clinicians) Good Fair Good Detailing and Validation- Selection Criteria

55. Pinching Unit Redesign – VA Rehabilitation Research & Development Center The final prototype selected from the above comparative analysis for further detailing is concept 2 Detailing and Validation- Selection Criteria Evolution of concept-2 throughout the project

56. Pinching Unit Redesign – VA Rehabilitation Research & Development Center • Sketches to dimensioned drawings • Drawings to AutoCAD data files for slices • AutoCAD dxf files to Laser cutter • SolidWorks model from AutoCAD data • STL/IGES data exchange for CNC milling (possible CAM application) • Laser cutter slices assembly and finishing • Velcro assembly and fittings /Alternate details Detailing and Validation- CAD/CAM

57. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Final Prototype Images showing the comfortable strapping and grip posture Adjustability for lateral movement through caps

58. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Final Prototype – Working Drawings/ Platform ` Platforms with High Visibility Thumb calibration

59. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Final Prototype – Working Drawings/ Caps Different sized caps

60. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Final Prototype – Cost Specifications • Raw material (wood-Balsa, Bass) ___ U.S.$ 12.50 • Glues/Adhesives ___ U.S.$ 2.75 • Laser cutter running cost ($2.5/Hr) ___ U.S.$ 7.50 • Velcro Straps ___ U.S.$ 3.00 Total Prototype Cost ___ U.S.$ 25.75 (INR 1,112)

61. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Final Prototype: Comparative Analysis with Existing Design • Eliminated the rings-only caps required • Two angles for lateral pinch posture • Compact proximal-distal adjustment • Mates with the current micro-scribe • Integrated Thumb calibration provided • Comfortable profile for the subject (fillets) • Better securement to the hand • Close to the correct position of Key-Pinch • Less interchangeable parts for Clinicians • Quick and easy adjustment of straps

66. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Final Prototype: Comparative Analysis with Existing Design • Eliminated the rings-only caps required • Two angles for lateral pinch posture • Compact proximal-distal adjustment • Mates with the current micro-scribe • Integrated Thumb calibration provided • Comfortable profile for the thumb (fillets) • Better securement to the hand • Close to the correct position of Key-Pinch • Less interchangeable parts for Clinicians • Quick and easy adjustment of straps

72. Pinching Unit Redesign – VA Rehabilitation Research & Development Center • Better finish prototype with CNC milling or rapid prototyping (assembly drawings ready) • Minimum 3mm distance can be achieved by cantilever and 2nd lever application (Conceptual sketches already discussed) • Concept-7 can be developed further with CNC machined elastomeric material for comfort fit (assembly drawings ready) • Caps can be eliminated through telescopic assembly in the shaft, which would provide quicker and compact assembly(Conceptual sketches already discussed/optional) • Robotic arm sensor can be calibrated with Gyro and Micro scribe to be used as pinching unit • Pinch pulling through friction can be tested for very small gap openings Future Scope

76. Pinching Unit Redesign – VA Rehabilitation Research & Development Center • Better finish prototype with CNC milling or rapid prototyping (assembly drawings ready) • Minimum 3mm distance can be achieved by cantilever and 2nd lever application (Conceptual sketches already discussed) • Concept-7 can be developed further with CNC machined elastomeric material for comfort fit (assembly drawings ready) • Caps can be eliminated through telescopic assembly in the shaft, which would provide quicker and compact assembly(Conceptual sketches already discussed/optional) • Robotic arm sensor can be calibrated with Gimbals and Micro scribe to be used as pinching unit • Pinch pulling through friction can be tested for very small gap openings Future Scope

78. Pinching Unit Redesign – VA Rehabilitation Research & Development Center 2nd Discussions/Iterations/Clinician’s Interaction - 8/16/2005 • Satisfied with the development of the final prototype • Likes the idea, that improved design is in coherence with current system • Soon the prototype would be developed in the final product (Manufacturing) • Would like to observe the subject’s interaction with the final design, and would notify Design team of results and necessary changes, if required

79. Pinching Unit Redesign – VA Rehabilitation Research & Development Center Thank you !

GRASP REDESIGN STANFORD

Recomendados

Recomendados

Más contenido relacionado

Destacado

Destacado (20)

Similar a GRASP REDESIGN STANFORD

Similar a GRASP REDESIGN STANFORD (20)

Más de Ruchin Chaudhary

Más de Ruchin Chaudhary (6)

GRASP REDESIGN STANFORD