A steering system of a new mobility-aid vehicle: Tread-walk

In Japan, independent living and freedom of movement are expected, even by aged persons, and the importance of preventive medicine and walking as part of overall efforts to maintain health are continuously promoted. To those ends, we have been developing a new mobility device, known as Tread-Walk (TW), which incorporates the following concepts: ldquoimproved mobility,rdquo ldquohealth maintenance,rdquo and ldquoa natural walking appearance.rdquo The device operates by means of three controls: a free treadmill velocity control (which allows the user to walk at their desired velocity), a driving control, and a steering control. In this paper, we propose an innovative steering control method that enables users to turn the device in a safe and stable manner. The newly developed steering system was designed to provide optimum support to the physical characteristics of elderly people. Furthermore, the rotational system of the device was constructed in a way that takes into consideration the centrifugal force imposed on the center of gravity of a person who is walking or standing. A number of simulations were conducted into the properties of our new steering system and it was determined that the rotation of the TW system could be safely implemented.