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Smart Cane – P14043 Sub-Systems Design Review. Lauren Bell, Jessica Davila, Jake Luckman, William McIntyre, Aaron Vogel. Agenda. Project Scope Concept Selection Engineering Requirements Component Breakdown Engineering Analysis Test Plan Risk Analysis Project Plan
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Smart Cane – P14043Sub-Systems Design Review Lauren Bell, Jessica Davila, Jake Luckman, William McIntyre, Aaron Vogel
Agenda • Project Scope • Concept Selection • Engineering Requirements • Component Breakdown • Engineering Analysis • Test Plan • Risk Analysis • Project Plan • Audience Feedback Please
Concept Selection • Final Concept Ideas • Finger Scroll • Palm Roller • Palm Roller and Finger Scroll • Final Concept Selection • Palm Roller without Finger Scroll
Design Grip Pressure Spec • Ensure handle functions under excessive grip • Measure pressure of displaced air for rough idea • Median pressure ~3 psi • Compare to Grip Pressure Study* • FSR sensors on glove • “Crush grip” measured on 50mm diameter handle • 5 male and 5 female adults • Maximum pressure ~3.1 psi • Our measurements matched the study, therefore: • Marginal Grip Pressure: 3 psi • Maximum (Design) Pressure: 5 psi * Tao Guoqiang; Li Jun yuan; Jiang Xian feng, "Research on virtual testing of hand pressure distribution for handle grasp," Mechatronic Science, Electric Engineering and Computer (MEC), 2011 International Conference on, pp.1610,1613, 19-22 Aug. 201
Required Motor Torque • Maximum moment could happen when: • Grip reaches design pressure • Pressure force is perpendicular to contact point • Palm contact area is maximum on roller • Two rollers are contacted • Maximum moment caused by design pressure • 50.1 oz-in • Motor selection will not be heavily constrained • Variety of motors that meet torque, size and rotation requirements
Motor Type Selection • Design Factors to meet Engineering Requirements • Rotational speeds of 50 to 70 RPM • Commonly available at 50 oz-in
Engineering Analysis:Bump Rotation Characteristics • Effective haptic zone – lower palm • Effective Bump Height • Bump Frequency
Bump Rotation/Roller Analysis • Bumps per rotation • Servo to Roller Spacing • Effectiveness of our model – Audience?
Handle Material Selection • Desirable Qualities • Moisture wicking • Higher Coefficient of Friction • Possible Options • Softex • Neoprene • Tennis Racquet Handle Cover • Top Choice • Synthetic Cloth - Nylon • Tennis Racquet Handle Cover
Immediate Next Steps • Engineering Analysis [ 10/28] • Power Requirement • Moment of Inertia • Research “standard” haptic sensitivity • Electrical Subsystem [10/31 ] • Engineering standards electrical design must meet • Design power supply • Layout sensor, micro and power supply location • Estimate weight distribution • Pseudo code • Mechanical Subsystem [ 10/31] • CAD drawings • Assembly drawings • Select shelf parts • Test Plan [ 10/28] • Establish and draft test plans • Risk Growth Curve [Weekly]