1. Cross Slope Compensation for Wheelchairs David Dar Marc C. Moore Alexander A. Abraham Advisor: Dr. Mark Richter

2. The Problem Currently wheelchairs do not have a mechanism to prevent involuntary veering on cross-slopes Subjects are forced to apply more torque on one wheel to maintain straightforward motion

3. Design Criteria Add-on feature to current wheelchairs Cost-friendly Aesthetically appealing Light-weight Mechanically simple Robust, durable

4. The Solution A mechanism that restricts rotational movement of a front wheel Forces wheelchair to travel in a single direction without deviation Applied only when the subject deems it necessary

5. Our Design Preliminary model of the caster wheel Caster features two surfaces separated by ball bearings Upper contingent smaller than lower contingent

6. Our Design Ring with teeth along the radial and axial axes, which surrounds central post By default, the spring- loaded ring is suspended above the lower surface When activated, ring snaps down and locks with lower plate

7. Concerns Solves problem Mechanism inadvertently activating Reliability - Mean Time Between Failure (MTBF) Ease of use Warning of hazards

8. Work Completed Researched ADA regulations Researched wheelchair mechanics (lab visits, journal publications, etc.) Constructed initial 3-D model Consulted several times with Dr. Mark Richter (Vanderbilt University, MAX-Mobility) Submitted NCIIA proposal Established project website

9. Current Work Increasing proficiency with Pro Engineer Forming basic caster model with the CAD program Using established manufactured caster designs as samples

10. Future Work Complete CAD model Manufacture prototype from finished CAD model Analyze design effectiveness Re-design model and make adjustments accordingly Implement device alterations