直進・旋回走行時のステアバイワイヤ小径自転車の挙動

抄録

Currently, personal mobility vehicles (PMVs) are attracting attention as intermediate- or short-range transportation. Bicycles are familiar PMVs that are also environmentally friendly and convenient. A small-wheel bicycle saves space and is easy to carry. However, a small-wheel bicycle running at low speed has poor upright stability and maneuverability. The purpose of this study is to improve its running stability by adopting a steer-by-wire system, which independently operates the steering gear and the tire. Sensors obtain the handle angle and actuators, instead of force from a mechanical connection, change the steering wheel angle. In this study, we carried out two experiments. First, we carried out straight running experiments to confirm the steering accuracy, upright stability, and maneuverability on a straight course. Second, we carried out turning experiments to confirm the upright stability and maneuverability on a course requiring changes in driving direction. It was confirmed that the proposed mechanism enhanced the upright stability compared with that of a conventional small-wheel bicycle. However, the maneuverability evaluations by the drivers showed that a conventional small wheel bicycle was better than the proposed steer-by-wire bicycle. The delay of motor control and the moment of inertia of the gearing might be the causes of this performance issue.