WHEELCHAIR DESIGN IN DEVELOPING COUNTRIESOffered spring 2008 – 9 credits, meets TR3-4pm

http://web.mit.edu/sp.784/www

Motivation: Show students how they can use technology to improve the lives of others by advancing wheelchair technology

Activities of studentsin the class:•Learn the technical, social, and economic factors preventing appropriate wheelchair technology from being implemented

•Study engineering, business, and biomechanics theory in context of wheelchairs

•Work in teams, collaborating with developing country partners and wheelchair specialists, to design and prototype wheelchair technology

•Interact with faculty, professional, and community partners during guest lecturers

•Participate in summer fellowships in developing countries to implement class projects

Locations of 2008partner workshops

1. Define projects with workshops

(Aug-Sept)

3. Test and implement (June-July) 2. Develop ideas

and prototype (Feb-May)

Co

llabo

rate Wheelchair experts

Students travel to

workshops

Dis

sem

inat

e

Class project development cycle

2007 class projectsTwo-speed tricycleObjective: Improve functionality, comfort, and efficiency of tricyclesImplemented in: APDK, Kenya; DAGE, Mobility Care, Tanzania

APDK model

How it works

•Pedal forwards: figure-8 ratchets and you drive normally

•Pedal backwards: normal chain ratchets at wheel and figure-8 chain drives forward

Normal side Figure-8 side

DAGE/Mobility Care model

Normal side Figure-8 side

Full prototype

Full prototype

Folding 3-wheeled wheelchairObjective: Modify the popular African-made three-wheeler to have a folding frame for easier transport in busses, car trunk, etc Implemented in: Mobility Care, KCMC Wheelchair Workshop, Tanzania

Contact

Screw preload

Coupling used: double angle iron

Directions of NO motion

Not used: double U-stock coupling (under-constrained)

Screw preload

ContactDirections of NO motion

Wiggling

Improved tricycle frame designObjective: Best use local materials to make tricycle frame stronger, lighterImplemented in: APDK, Kenya (elements of project used, but not full frame)

Material comparison for tube stock sizes

DAGE/Mobility Care model

CAD Model

Prototype

Elements used in Kenya

Dia (mm)

Thick(mm)

Wt(kg)

Cost (USD)

Moment of Inertia (mm 4̂)

Bending Moment (N*m)

Stiffness (N*m 2̂)

BM/Wt

Stiff/ Wt

BM/Cost

Stiff/Cost

Cost/ Weight

16 1.2 3.02 4.55 1538 99 308 33 102 22 68 1.5116 1.5 3.55 4.80 1815 117 363 33 102 24 76 1.3520 1.2 3.61 5.22 3144 163 629 45 174 31 120 1.4520 1.5 4.11 5.77 3754 194 751 47 183 34 130 1.4022 1.2 3.80 5.54 4255 200 851 53 224 36 154 1.4622 1.5 4.55 6.33 5102 240 1020 53 224 38 161 1.3922 2 6.07 6.71 6346 298 1269 49 209 44 189 1.1025 1.2 4.66 5.93 6369 263 1274 57 273 44 215 1.2725 1.5 5.76 6.97 7676 318 1535 55 267 46 220 1.2125 2 6.98 7.68 9628 398 1926 57 276 52 251 1.1032 1.2 5.62 6.79 13790 446 2758 79 491 66 406 1.2132 1.5 6.78 7.84 16753 541 3351 80 494 69 427 1.1632 2 9.02 9.96 21300 688 4260 76 472 69 428 1.10

33.5 1.2 5.88 7.08 15902 491 3180 83 541 69 449 1.2033.5 1.5 7.14 8.24 19344 597 3869 84 542 73 470 1.1538 1.2 6.72 8.22 23510 640 4702 95 700 78 572 1.2238 1.5 8.28 9.53 28692 781 5738 94 693 82 602 1.15

38.7 1.2 6.80 8.21 24876 665 4975 98 732 81 606 1.2138.7 1.5 8.22 9.48 30373 812 6075 99 739 86 641 1.1542.25 1.2 7.54 9.11 32625 799 6525 106 865 88 716 1.2142.25 1.5 9.06 10.47 39914 977 7983 108 881 93 763 1.16

45 1.5 9.66 11.27 48544 1116 9709 115 1005 99 862 1.1748.25 1.2 8.60 10.39 49114 1053 9823 122 1142 101 945 1.2148.25 1.5 10.38 11.98 60248 1291 12050 124 1161 108 1006 1.15

50 1.2 8.64 10.90 54798 1133 10960 131 1268 104 1005 1.2650 1.5 10.74 12.41 67265 1391 13453 130 1253 112 1084 1.1660 1.2 10.70 13.47 95842 1652 19168 154 1791 123 1423 1.2660 1.5 13.02 15.89 118006 2034 23601 156 1813 128 1485 1.2276 1.5 16.56 23.02 243667 3316 48733 200 2943 144 2117 1.3976 2 21.75 26.53 318495 4334 63699 199 2929 163 2401 1.22

88.9 1.5 19.18 27.08 393381 4576 78676 239 4102 169 2905 1.4188.9 2 25.74 28.76 515679 5999 103136 233 4007 209 3586 1.1288.9 2.5 32.22 35.98 633730 7372 126746 229 3934 205 3523 1.12

Marketing strategies for local workshopsObjective: Increase exposure of workshops’ mobility products, educate usersImplemented in: Mobility Care, KCMC Wheelchair Workshop, Tanzania

Logo design

Info packet for wheelchair users

Brochure

Manual for making a FREE website from an internet café

http://make.a.website.on.googlepages.com