RehabMove 2018: SIMULATING THE MANUAL WHEELCHAIR FREE TURNING DECELERATION

Adequate manual wheelchair (MWC) configuration is crucial for efficient MWC locomotion. Evaluating the effect of various configurations can be done through simulation, which relies on the definition of a mechanical model. The aim of this paper was to propose and evaluate a simplified mechanical model of a rolling and turning MWC. MWC decelerating motion following a rotational impulse was simulated based on MWC geometry, anteroposterior load distribution, and wheel and ground materials. Mechanical equations of a free rolling and turning MWC were obtained. Linear and angular accelerations were linked to geometric and inertial settings of the MWC and to the wheel mechanical behaviors. To evaluate this model, one MWC, loaded with fixed additional masses and instrumented with inertial measurement units, was accelerated in rotation and let decelerate freely. Ground and wheels materials were used to assess the wheel rolling and turning resistances parameters from literature data, whereas MWC inertial parameters and geometries were measured. These values were used as inputs for simulations. Evaluation of the simulation was performed by comparison between simulated and measured decelerations. Results show that the simulated and measured trajectories were close but that simulated angular decelerations were underestimated. Finally, if simulation of free moving MWC showed the link between settings, rotational and translational behavior, simplifications on the measurement process may have altered the accuracy of the simulations. This approach is nevertheless promising by shortening the process of setting selection and may have applications on energetic characterization, MWC setting optimization or occupational therapist training. Further works would focus on the extension of the mechanical model, in particular to include inclined surface and a moving MWC user