UBC Theses and Dissertations
Biomechanical modeling and analysis of manual wheelchair propulsion Mallakzadeh, Mohammadreza
Users of manual wheelchairs depend on wheelchairs for most of their daily activities. Manual Wheelchair Propulsion (MWP) is an inefficient and physically straining process, which in the long term can cause injury. However, wheelchair users do benefit greatly from cardiovascular exercise with the use of manual wheelchairs. The first step in improving the low efficiency and/or preventing injuries during MWP is to be able to measure these factors. To do this, we have proposed an Equivalent Biomedical Index (EBI) and two Wheelchair Users' Joint Injury Indices (WUJII and WUJII') for gross mechanical efficiency and injury assessments. We have fabricated and validated an instrumented wheel to measure the user's applied loads on the handrim during MWP as part of the data required for calculating the proposed indices. The wheel system has been verified by using general uncertainty analysis, and its specifications have been determined using both static and dynamic experiments. The results have ensured the reliability of the system. Also, a procedure has been developed to determine the angular position of the contact point between the hand and the handrim by using the applied loads and without the use of cameras. This study also focuses on proposing a novel method to determine the optimum seat position of the wheelchair to minimize the values of the injury indices and/or maximize the value of EBI for each user. Eight male wheelchair user subjects were recruited for the experiments. Statistical analysis showed that horizontal seat position was significantly related to all three indices (p <0.05). The response surfaces of the indices for two users were determined by using the proposed method and a Bivariate Quadratic Function. We developed and elaborated "Method I" for analysis of the dynamics of user joints and to calculate the joint loads as part of the factors required to define the optimum seat position. A 3D rigid-body inverse dynamic method was used to calculate the joint loads. "Method II" for analysis of the kinetics of the upper limbs was developed and validated to simplify the experimental procedure and decrease the required post-processing. Method II showed to be reliable for measuring the joint forces.
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