Development of a Human-Friendly Omni- directional Wheelchair with Safety, Comfort and Operability Using a Smart Interface

A variety of wheelchairs with different options and special add-on features have been developed to meet a wide range of needs (Pin & Killough, 1994), (Wada & Asada, 1999), (West & Asada, 1992). In order to satisfy the demand for higher mobility, designers have created new driving concepts such as omni-directional movement which allows any combination of forward, sideways, and rotational movement, thus ensuring users much more freedom and safety in wide or narrow spaces. Autonomous electric wheelchairs are very useful for people who cannot move their upper bodies freely. However, these wheelchairs need to be fitted with a central control unit and high-level sensors capable of realizing complex navigation and obstacle avoidance tasks, based on a description of the environment and final goals marked out by those sensors. Since autonomous wheelchairs can function well only in special environments, this mode greatly limits the user's freedom. In order to offer users with a higher degree of independence, the user-controlled movement mode, or semi-autonomous mode, which is operated under absolute user control by an input device such as a joystick, switch, monitor, etc., has been developed. The main difference between autonomous and semi-autonomous systems is that in semi-autonomous systems users interact in real time to perform certain tasks in dynamic environments. Under user control, the wheelchair can go wherever the user wants it to. Therefore, this mode provides a high degree of user independence. However, it is necessary to keep in mind that some elderly people or handicapped people can not use their arms due to weakness or injury. These people need the help of an attendant. In developed countries in which the number of young people is declining yearly, some healthy elderly people are taking care of other elder or handicapped people. For these attendants, a system that helps them to push the wheelchair and its occupant would be very convenient.