Experimental study on a novel manual wheelchair

BACKGROUND: Traditional manual wheelchair users suffer from upper limbs injuries due to the propulsion gesture. OBJECTIVE: This paper presents the experimental activity addressed to define the dynamic characteristics of a novel manual wheelchair. The design and realization of the wheelchair aim to reduce injuries of the upper limbs related to conventional wheelchairs. A new index called Peak Of Force, POF, is defined and applied to the different wheelchair manual propulsion systems. METHODS: The wheelchair speed and the left and right-hand forces exerted by the user are monitored. The tests have been performed by changing the transmission ratio of the wheelchair and the wheelchair speed. RESULTS: The indices MEF and FEF are lower than 100% due to the lateral and radial forces for hand-rim wheelchairs and handbikes. For Handwheelchair.Q these indices are equal to 100%. The mean value of index POF for Handwheelchair.Q is 51.75 %, while it is about 42.5% for the hand-rim wheelchair, and 57.6% for the handbike. CONCLUSIONS: The user forces for Handwheelchair.Q depend on the wheelchair speed and the pulley radius. The larger pulley radius reduces the average and the maximum force. A variable transmission ratio can be implemented on the proposed wheelchair.