Akira Kakimoto

Development of power-assisted attendant-propelled wheelchair

Attendant propelled wheelchairs are driven by people who often feel necessity for power assistance while pushing them up or going down on ramps, sideslopes or curbs. We propose a novel power-assisted wheelchair with a force sensing mechanism. A DC motor and a differential gear are employed. The power assistance is controlled as if it were always operated on a solid flat ground. The control algorithm is based on a model reference adaptive control (MRAC). A prototype was made and initially tested. It was found effective to reduce operators driving force.

Development of a cart for independent mobility assistance for non-ambulatory children

Some parents of non-ambulatory children are not eager to allow their children to use powered wheelchairs because of apprehension of further deterioration of their functionality and the risk for accidents. The authors think that not all but some such children could develop their ability to operate powered wheelchairs and might expand their knowledge about the circumstances and interests in them. Thus we made a prototype cart for them eventually to experience motion by themselves. Based on a 6-wheeled chassis, the two middle wheels are driven with a traction roller drive system. We had been testing this prototype with a child with cerebral palsy for one year. Acquisition of skills in pushing switches and enjoyment of motion were confirmed. However, we encountered several problems such as difficulty in rolling on a carpet and in handling due to its weight. The ability to record moving speed and operation of input devices helps rehabilitation experts to conduct quantitative performance evaluation. To solve these problems, we manufactured another prototype. The second prototype was tested with another child with cerebral palsy for one year. The problems were solved. She acquired the operation skills necessary to operate the prototype with four switch operation.

Development of wheelchair with assistive power unit

A wheelchair with an assistive power unit employing a differential gear is now under development. The wheelchair is specially aimed at those who have little residual power to drive a manual wheelchair, but often use a powered wheelchair. People who have C5 or C6 level spinal cord injury or the aged who have lower limb impairment are initially considered. The purpose is to encourage them to keep their residual ability or even to improve it by adjusting the assistive power. In addition to performance tests following JIS test procedures, 11 subjects, manual wheelchair users, tried the prototype and found its operation easy and that it is helpful while ascending or descending a slope.<<ETX>>

Development of Wheelchair with Assistive Power Unit

A wheelchair with an assistive power unit employing a differential gear is now under development. The wheelchair is specially aimed to those who have a little residual power to drive a hand driven wheelchair, but often use a powered wheelchair. People who have C5 or C6 level spinal cord injury or the aged who have lower limb impairment are initially considered. The purpose is to encourage them to keep their residual ability or even to improve it by adjusting the assistive ower. A prototype has been developed and tested on experimental basis. The prototype has one DC servo motor(120W)and the output torque is transmitted to rear wheels through a differential gear, Oldams shaft couplings and electromagnetic clutches. Applying voltage to the clutches turns the land-driven wheelchair into a powered wheelchair. The control system is utilizing an 8 bit single chip microcomputer and rotation angle sensors. Velocity feedback control is installed in the oftware. In addition to performance tests following the JIS test procedures, 11subjects, hand-driven wheelchair users tried the prototype and found its operation easy and that it is helpful when ascending or descending a slope.