Accessible Wheelchair Storage.

Early conversations focused on what the user wanted to carry, what she could reach independently, and how a storage system could fit around the geometry and movement of her existing wheelchair.

USER CONTEXT

During design conversations, the user emphasized everyday practicality: carrying items such as a water bottle, laptop, grabber, and occasional groceries while still being able to reach them independently.

Earlier requirements: support at least a 13 in laptop · detachable · quick assembly · no permanent marks on the wheelchair.

Numbers above are design targets set during development. They are not all formally validated performance results — see 11 Final Prototype for what the prototype demonstrated.

The team intentionally separated the problem into two challenges: how should the storage move, and what should the storage itself look like?

Low-fidelity prototypes let us explore accessibility, compactness, and modularity before committing to a single mechanical architecture.

The final direction centered on a rail-and-arm mechanism that could keep the storage behind the wheelchair during normal use and move it toward the side when the user needed access.

This approach addressed a core Human Factors conflict: storage needed to remain out of the way during mobility while still becoming reachable without assistance.

1. TRAVEL POSITION

   Behind chair

2. MOVE ALONG RAIL

3. ACCESS POSITION

   Beside user

Once the mechanism direction was established, we developed the system in CAD to understand component relationships, clearances, attachment points, and overall geometry.

I contributed substantially to the CAD assembly and integration of the mechanism, using the model to understand how fabricated and purchased components would fit together before and during the physical build.

The design combined commercial structural components with custom fabricated parts. Rather than manufacturing every element from scratch, the mechanical challenge was integrating off-the-shelf extrusion and hardware with custom connectors, supports, and storage components.

The assembly required a combination of purchased hardware and custom components. Engineering drawings and CAD models helped translate the digital assembly into parts that could actually be fabricated and assembled.

• wheelchair connectors
• wheelchair supports
• frame components
• hooks / storage interfaces
• sliding or vertical-arm components
• custom printed parts

A major part of my role was translating the design into physical hardware.

I contributed substantially to manufacturing and fabricating components as well as assembling the mechanism, making adjustments as CAD geometry met real materials, tolerances, hardware, and wheelchair constraints.

Physical fabrication exposed issues that were difficult to understand from sketches alone.

Connections needed to be strengthened, sliding motion needed to become smoother, and the interface between metal structural members and custom printed components required refinement. The physical build therefore became part of the design process rather than simply the final step.

1. CAD
2. Build
3. Discover
4. Change

The final prototype demonstrated the core mechanical concept: storage positioned behind the wheelchair could be moved toward the user when needed while keeping the overall system close to the chair.

The mechanical challenge was not simply to build a moving storage rack. The mechanism existed because of a Human Factors problem: storage capacity was only useful if the person using the wheelchair could actually reach it independently.

Decisions about mechanism width, storage location, required movement, attachment points, and bag orientation were therefore tied directly to reach, strength, wheelchair geometry, and everyday routines.

1. USER NEED

   Access belongings independently

2. HUMAN FACTORS CONSTRAINT

   Limited reach to storage behind the chair

3. ENGINEERING REQUIREMENT

   Move storage into an accessible position without significantly increasing chair width

4. MECHANICAL RESPONSE

   Rail + movable arm mechanism

5. PROTOTYPE

   Physical system integrated with wheelchair

Using a combination of standard structural components and custom fabricated parts allowed the team to focus fabrication effort where customization mattered most: the wheelchair interface, mechanism geometry, and storage connection.

The prototype demonstrated the mechanical direction, but several areas would need further development before the system could become a refined product.

• improving the pulley / motion system
• reducing friction in the vertical-arm movement
• strengthening and simplifying the bag attachment
• refining custom wheelchair interfaces
• completing more rigorous load and durability testing
• designing a purpose-built collapsible storage bag
• exploring an adjustable frame architecture that could fit multiple wheelchair geometries

ON MOTORIZATION

Motorization was considered as a possible future direction, but a passive mechanical system would remain important for reliability, waterproofing, simplicity, and failure recovery.

This project gave me hands-on experience moving between Human Factors, CAD, fabrication, and physical product development.

One of the biggest lessons was how quickly a design changes once it moves from CAD into real hardware. Connections that appear straightforward digitally can become difficult once material thickness, hardware geometry, alignment, friction, and assembly access are introduced.

Because I worked extensively on the CAD assembly as well as fabrication and physical assembly, I was able to see that transition directly.

The project also reinforced that accessibility requirements can create meaningful mechanical design problems. The challenge was not simply to add storage to a wheelchair — it was to create storage that the user could actually access independently without compromising the way the chair needed to function.