RehabMove 2018: OPTIMIZING MANUAL WHEELCHAIR SETTINGS USING NUMERICAL SIMULATION TO IMPROVE MOBILITY IN VARIOUS DAILY-LIFE ACTIVITIES

Abstract Manual wheelchair (MWC) locomotion is an exhausting task for the upper limbs. Hence, reducing energy loss can improve users’ mobility. The purpose of this study was to investigate how numerical optimization could allow decreasing the energy loss (swiveling and rolling resistance) by numerically adjusting MWC settings, including seat height and anterior-posterior position, seat and backrest angles, and wheelbase. One participant performed a set of daily-life MWC maneuvers, including start-up, straight propulsion or u-turns using an instrumented wheelchair allowing handrims, seat, backrest and footrest forces and torques to be measured. These mechanical actions were used as inputs of a mechanical model to assess instantaneous values of rolling and swiveling resistances. This numerical model was parameterized with several settings, including fore-aft and vertical positions of the seat, wheelbase and seat/backrest angles. For each trial and each task, a numerical optimization procedure was designed and implemented in Matlab to find the configuration minimizing energy loss while ensuring no-tipping of the MWC. Numerical optimization allowed the total energy loss to be decreased. Optimal settings were different according to the trial and the task that was performed. This mobility improvement was reached at the expense of the overall stability. MWC settings optimization through numerical optimization allows defining a MWC configuration that would improve users’ mobility by decreasing energy loss by rolling and swiveling resistance. This preliminary investigation should be completed with a musculoskeletal model of the upper limbs to generate optimal wheelchair locomotion taking into account shoulder loading