Tsutomu Hashizume

Effect of Tire Pressure to Physical Workload at Operating a Manual Wheelchair

It is often experienced that low tire pressure of the wheelchair not only increases running resistance, but also reduces parking brake performance. In this study, the required driving forces for different tire pressures were experimentally measured and evaluated. It was indicated from the result that the wheelchair with proper tire pressure could be run with less workload of wheelchair-user. Then it was also indicated that the wheelchair with a lower tire pressure needed more workload of wheelchair-user even on hard level surface.

Study on the accessibility and assistive device between platforms and trains for manual wheelchair user

The gaps and steps between platforms and trains reduce the accessibility and mobility of persons with wheelchair in railway transportations. Using an experimental platform, the observations were performed how gaps and steps influence their capabilities for wheelchair users with spinal cord injuries. A quantity of normalized driving force (NDF) was introduced to evaluate the abilities of getting on/off trains. Dynamic wheelchair driving force was measured by using torque meter equipped on the wheelchair to analyze the power boarding on trains. To improve practical accessibility of persons with wheelchair, an assistive device for boarding trains was designed and verified.

Study on the wheelchair user’s body vibration and wheelchair driving torque when wheelchair is ascending / descending the boundary curb between pavement and roadway

The design of the boundary curb between pavement and roadway constructed in the crosswalk is requested to secure safety and smooth traffic for all passing people. It is preferable to set the step of curb to be about 2 cm for the visually handicapped persons to ascertain the boundary. However, this step is a barrier for the wheelchair user. This research aims the quantitative evaluation of the typical existing curbs from wheelchair userpsilas viewpoint, and the final proposal of the universal design of an easy-to-use curb for all. The wheelchair userpsilas body vibration and body load were examined by using the three directional accelerometers and the torque meter equipped wheelchair. It was shown to be able to evaluate the curb objectively by assuming the body vibration and the wheelchair driving torque as a measure.

Biomechanics and Physiology for Propelling Wheelchair Uphill Slope.

A vertical slope of sidewalks significantly inhibits to the mobility of manual wheelchair users in their daily life. International guidelines of the vertical slope are specified approximately 4% or 5% (1:20) gradient or less as preferred, and allow 8.3% (1:12) as its maximum when it is impossible. Relevant research of the physical strain for wheelchair users with pushing on slopes, and the validity assessment of slope guidelines have been investigated. However, the analysis for the effect of a slope distance and their transient performance are still remained. The purpose of this study is to clarify the physiological and biomechanical characteristics of manual wheelchair users that propelling a wheelchair on an uphill slope. We measured these data by a metabolic analysis system, a heart rate monitor system and an instrumented wheelchair wheel. Sixteen unimpaired subjects (non-wheelchair users) were examined to investigate the effect of a long slope with 120m distance and 8% gradient. And five wheelchair users with cervical cord injury were examined to evaluate the influence of different gradients (5%, 6.7%, 8.3%, 10% and 12.5%) with 3m length in laboratory. Our experimental results of the long slope showed that wheelchair propulsion velocity and power increased considerably at the beginning of the slope where the peak mean value of them were 0.96 m/s and 70.8W and they decreased linearly to 0.55m/s and 33.6W at final interval. A mean oxygen uptake and heart rate were increased as the distance increased and their results indicated the extremely high exercise intensity at a final interval that were 1.2liter /min and 152bpm. While wheelchair pushing cadence reduced after an initial interval, mean of strokes per10m increased to compensate the decrease of upper limbs power. The results of different gradients indicated that the normalized power of subjects with cervical cord injury was significant difference between each subject in the ability to climb a slope. Mean normalized power were 0.23W/kg on a 5% slope, 0.24W/kg on 6.7%, and 0.26W/kg on 8.3% respectively. Based on these findings, we examined the relationship between the theoretical normalized power and the lowest velocity to climb a slope, and we might indicate the ability to push on an uphill slope for the persons with manual wheelchair user.