Omniwheel - Senior Capstone Project
This product was designed to replace the castor style front wheels that are traditionally used on manual wheelchairs. Users with some lower body mobility often want to move by shuffling with their feet instead of rotating the rear wheels with their arms. If the user wishes to travel in the chair similar to how one would in an office chair, the wheels often hit the user’s feet. Redesigning the front wheel with no castor eliminates the interference of the wheels with the user’s feet, and improves the comfort and performance of the wheelchair.
Design Evolution
After initial design concepts were discussed, the team decided to pursue a design which used two piece concentric rollers to form the wheel's circular profile. Early design efforts were focused on the wheel's circularity and ensuring components could withstand the expected loads.
FEA analysis showed that a support ring was necessary to prevent buckling of the spokes. The spokes were changed from a straight to an angled design and the shape of the rollers was modified to bring the wheel much closer to a circular profile.
With redesigned rollers and angled spokes the team decided to decrease the spoke and roller sets from ten to nine in order to reduce the overall part count while still maintaining functionality. A design with eight was considered but through examination of the 3D model the team concluded it would not roll as smoothly as the nine spoke design.
The team opted for a two piece support ring instead of the previous one piece snap on design because it allowed for a more straightforward removal of the spoke and roller sets.
Bracket design was performed by another member of the project team. Using their model I created the final assembly of the wheel, bracket, and hardware. The final wheel design was just under nine inches in diameter, allowing it to traverse rough terrains better than the current castor wheels.
Prototype 3D Printed Design
The omniwheel was voted best biomedical project by professors and industry professionals at the senior design competition because of the team's innovative design approach to a challenging problem.
