Turning in Circles: Understanding Manual Wheelchair Use Towards Developing User-Friendly Steering Systems

Area of Science:

• Rehabilitation Engineering
• Biomechanics
• Human-Computer Interaction

Background:

• Manual wheelchairs are crucial for mobility but can be inefficient, requiring user coordination.
• Understanding wheelchair user behavior is vital for improving assistive device design.
• Inertial Measurement Units (IMUs) are used to analyze wheelchair movement patterns.

Purpose of the Study:

• To investigate the turning behavior of full-time manual wheelchair users.
• To gather data for developing novel steering systems that utilize kinetic energy.
• To lay the foundation for improved wheelchair designs.

Main Methods:

• 14 full-time manual wheelchair users participated in a week-long study.
• Three wearable sensors (IMUs) were attached to each wheelchair.
• Turns were identified by differences in rear-wheel velocity; kinematic characteristics were analyzed.

Main Results:

• A turn was detected every 3.6 meters, averaging ~900 turns daily.
• Median turning radius for moving turns was 1.09m with a 39° angle.
• Turns-on-the-spot (median 89° angle) comprised ~25% of turns, often starting from a standstill.

Conclusions:

• Daily wheelchair use involves frequent, small adjustments and distinct turning strategies.
• Users may intuitively optimize energy by using on-the-spot turns for orientation and moving turns for navigation.
• Further research is needed to understand how wheelchair design influences user movement patterns.