Proximity sensing and movements of omnidirectional mobile electric wheelchair for autopilot

This study was done to develop an autopilot system to govern the movements of an electric wheelchair. For actualizing the autopilot, we intend to reduce accidents to the minimum by governing the extent of a user´s control. As a mobile mechanism, we used mechanical wheels with barrel tires to realize omnidirectional movements. Four motors drive four wheels that are independently controlled by a microcomputer. We consider both cost and simplicity in this system, which incorporates a monocular depth camera and ranging sensors. For this study, we developed an omnidirectional electric wheelchair prototype named Glimmer. We examined the use of environment sensing with ranging sensors to measure close range distances to stop. We evaluated a measurement range of distances obtained using the actual environment. The experimentally obtained results reveal that the mean error rate was 5.7 % with the range of the distance of 9.0-46.5 cm. We actualized the function of movement using the sensors. The device can stop with a valid margin before contacting an object.