Cross Slope Compensation for

WheelchairsDavid Dar

Marc C. MooreAlexander A. Abraham

Advisor: Dr. Mark Richter

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

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

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

Our Design Preliminary model of

the caster wheel Caster features two

surfaces separated by ball bearings

Upper contingent smaller than lower contingent

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

Concerns Solves problem Mechanism inadvertently activating Reliability - Mean Time Between Failure

(MTBF) Ease of use Warning of hazards

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

Current Work Increasing proficiency with Pro Engineer Forming basic caster model with the CAD

program Using established manufactured caster

designs as samples

Future Work Complete CAD model Manufacture prototype from finished CAD

model Analyze design effectiveness Re-design model and make adjustments

accordingly Implement device alterations