A Study on the Running of a Joystick-Type Six-Wheeled Electric Wheelchair When Curb Climbing

In Japan, the number of power wheelchair users is increasing as the country becomes an aging society. This trend is expected to continue in the future. Electric wheelchairs currently on the market include (1) bar-handle-type power wheelchairs for older users and (2) joystick-type power wheelchairs that change direction by operating a joystick. When such electric wheelchairs are used outdoors, the problem is curb-climbing at the boundary between the roadway and the sidewalk. It would be difficult for a wheelchair with a small front wheel diameter of 200 mm to overcome a curb height of 50 mm. Therefore, users are forced to take a detour or drive on the street to avoid the curb step. One of the most effective ways to solve this problem is to increase the wheel diameter. However, larger wheels make it more difficult for users to get in and out of the wheelchair. In addition, there are problems such as an increased footprint when turning, which makes the wheelchairs difficult to use on narrow streets. In this paper, using a joystick-type six-wheel electric wheelchair as an example, we examined the mechanism by which an electric wheelchair can overcome curb climbing and consider improvements to the chassis with a method that does not rely on increasing the wheel diameter. As a result, it became possible to overcome a curb of 96 mm in height with a front-wheel diameter of 200 mm.