SINGLE POINT CENTER OF PRESSURE FOR WHEELCHAIR PROPULSION

Authors: David P VanSickle, Rory A Cooper, Rick N Robertson, Sean D. Shimada, Michael L. Boninger

Abstract:

Wheelchair propulsion is inherently a three dimensional activity without a single plane of analysis appropriate for all circumstances. Unfortunately, there is not a general solution for a three dimensional center of pressure (COP). Therefore, a least squares solution is sought. The COP is the point where the measured force applied by the hand to the pushrim would result in the measured moment. An algorithm is developed for the determination of an optimal single point COP by use of the pseudoinverse (Moore-Penrose inverse) and implemented in MatLab [2]. Kinetic data were collected from eight subjects using the SMARTWheel [1,4], and kinematic data were collected using a PEAK5 video analysis system. The center of pressure is displayed graphically relative to the hand. Each graph may be rotated dynamically by the program user.

Address: David VanSickle Human Engineering Research Laboratories Veterans Affairs Medical Center 7108 Highland Drive, 151R-1 Pittsburgh, Pennsylvania 15206 TEL: (412) 365-4851 FAX: (412) 365-4858