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04 · Team Project, ME 263

Height-Adjustable Wheelchair

A full-semester mechanical design project — a scissor-lever wheelchair mechanism carried from customer requirements through CAD, costed prototype, and a formal economic justification.

Team
"Mechanical Monsters, Inc." — Akshat Singh, Jack Ferlazzo, Trenner Jones, Alexander Phan
Timeframe
Spring 2022
Tools
SolidWorks, QFD/House of Quality, NPV/ROI modeling
Deliverables
3 progress reviews, final poster & prototype

The problem

Standard wheelchairs force caregivers into awkward, back-straining transfers, and force users to give up independence in getting into and out of the chair. Our target customer requirement, quantified through a formal House of Quality: an affordable, easy-to-use, adjustable-height wheelchair that reduces physical strain on both the user and anyone assisting them — without pricing itself out of reach.

House of Quality QFD matrix comparing wheelchair customer requirements (affordable, easy to use, comfortable, safe, durable, height adjustable) against engineering specifications, benchmarked against a gait belt, transfer board, and sit-to-stand wheelchair.
Fig. 1 — House of Quality: customer requirements weighted against engineering specs and existing solutions.QFD, PR1

Approach

We ran the requirements through a full House of Quality to translate qualitative needs ("comfortable," "safe," "storable") into weighted, measurable engineering targets — cost per unit, weight capacity, height-adjustment time, footprint — benchmarked directly against existing alternatives like gait belts and sit-to-stand wheelchairs. That drove the concept toward a scissor-lever lift mechanism, which we developed in SolidWorks across three progress reviews, refining the mechanical-advantage geometry and part selection at each stage.

Each phase carried its own costed bill of materials, and the final design was backed by an NPV, ROI, and break-even analysis to make the business case for the concept, not just the engineering case.

Bill of materials table for the wheelchair listing frame, wheels, brakes, armrest, scissor jack, and other components with unit costs and total line costs.
Fig. 2 — Costed bill of materials for the final prototype.Progress Review 3
$275
Total costed prototype build, itemized down to the fastener
19.4%
Highest-weighted House of Quality spec: height-range adjustability
3
Progress reviews of CAD/BOM iteration before final poster

Result

A working scissor-lever prototype with a fully costed BOM and a defensible economic case, presented as a final poster after three rounds of design iteration. It's the clearest "concept through prototype" lifecycle project in my portfolio — QFD in, working hardware and a costed BOM out.

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