Objective For the wheelchair user, door to door vehicles are a necessary method of transportation. However, when wheelchair users drive a vehicle, they have to make use of driving support equipment, and they must adapt themselves to the vehicle. It has been clarified that when wheelchair users drive they have difficulty maintaining body position in the situation of receiving the effects of centrifugal force, such as on curves. This paper is concerned with this driving situation and the development of “body support equipment” for wheelchair drivers which can keep body posture and not effect the driving operation in such a situation.
Main Content To understand the driving load for wheelchair drivers, the situation of driving on curves, which is the most stressful condition, was examined. Evaluation methods for both the driver and the vehicle were used to clarify the questionnaire, muscle activity, three-dimensional motion, steering-wheel angle, and acceleration-velocity.
Results On the left curve, the seating posture is easily changed because of the operation style. Therefore, body support by the seat became lower, so muscle load on the left curve was basically higher. Also, the main opinion of the drivers was a difficulty to keep body posture, so the left curve has a lower evaluation than the right curve. On the right curve, the operation style keeps body posture strongly through centrifugal force. However, around the end of the curve, the balance between centrifugal force and keeping posture is broken, and turning back the steering becomes later than on the left curve. Therefore, at the end of the curve, the vehicle swerves strongly and the muscle load of the right shoulder is greater. It is possible to keep the body posture securely on the right curve and the driving is easier. However, the vehicle is less stable than the left curve.
Conclusion Several organizations have been approached for both long-term and short-term counter measures. Short-term measures are proposed for the vehicle interior using driving support equipment that can ensure a stable sitting posture. The design proposed in this paper has the advantages of low cost and easy replacement to another vehicle.