Study of Electric Wheelchair Enabling Ascend Spiral Stairs Using Crawlers and Wheels

We have developed a simple mechanism that can ascend spiral stairs using two steering wheels, one prismatic joint on the rear wheel, and rotating arms with crawler and wheel that keeps a wheelchair body horizontal. In this study, first, we defined four problems when ascending the spiral stairs. Second, we proposed a mechanism to solve four problems which combines above mentioned components, and designed a one third scale experimental machine. Finally, the experiment using one third scale spiral stairs are conducted, and results showed that proposed mechanism can ascend to the second step of stairs keeping its posture horizontally. Furthermore, it turned out that it is unable to climb from the third step onwards because the rear wheel is floating. By applying pushing force to the front wheel appropriately, it is known that the experimental machine can ascend stairs.