title: Impact of Mass and Weight Distribution on Manual Wheelchair Propulsion Torque.
abstract: Propulsion effort of manual wheelchairs, a major determinant of user mobility, is a function of human biomechanics and mechanical design. Human studies that investigate both variables simultaneously have resulted in largely inconsistent outcomes, motivating the implementation of a robotic propulsion system that characterizes the inherent mechanical performance of wheelchairs. This study investigates the impacts of mass and mass distribution on manual wheelchair propulsion by configuring an ultra-lightweight chair to two weights (12-kg and 17.6-kg) and two load distributions (70% and 55% on drive wheels). The propulsion torques of these four configurations were measured for a straight maneuver and a fixed-wheel turn, on both tile and carpet. Results indicated that increasing mass to 17.6-kg had the largest effect on straight acceleration, requiring 7.4% and 5.8% more torque on tile and carpet, respectively. Reducing the drive wheel load to 55% had the largest effect on steady-state straight motion and on both turning acceleration and steady-state turning; for tile and carpet, propulsion torque increased by 13.5% and 11.8%, 16.5% and 4.1%, 73% and 5.1%, respectively. These results demonstrate the robot's high sensitivity, and support the clinical importance of evaluating effects of wheelchair mass and axle position on propulsion effort across maneuvers and surfaces.
authors.affiliation: a Rehabilitation Engineering and Applied Research Laboratory , Georgia Institute of Technology , Atlanta , Georgia , USA.|b School of Mechanical Engineering , Georgia Institute of Technology , Atlanta , Georgia , USA.|c School of Applied Physiology , Georgia Institute of Technology , Atlanta , Georgia , USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Sprigle
authors.affiliation: a Rehabilitation Engineering and Applied Research Laboratory , Georgia Institute of Technology , Atlanta , Georgia , USA.|b School of Mechanical Engineering , Georgia Institute of Technology , Atlanta , Georgia , USA.
authors.forename: Morris
authors.initials: M
authors.lastname: Huang
mesh_terms: D000054:Acceleration; D004867:Equipment Design; D006801:Humans; D055595:Mechanical Phenomena; D008962:Models, Theoretical; D012371:Robotics; D019415:Torque; D014910:Wheelchairs
keywords: energy loss; inertia; manual wheelchair; propulsion; torque