Evaluation of Rider’s Behaviour in Sitting Posture Supposing Sit-Riding Balancing Type PMV

Abstract

For sit-riding type wheeled inverted pendulum personal mobility vehicle (WIP PMV), a rider operates it in a sitting posture and a weight-shifting motion is achieved by only rotating an upper-body around a waist. This causes a drop of acceleration and deceleration ability of the PMV, as more, a rider feels anxious when the PMV inclines back and forth while accelerating and decelerating. To cope these issues, it is important to know rider’s behavior in a sitting posture on an unstable seat and to adopt the characteristics in a driving controller of the PMV. In this paper, we investigated a balancing ability and a rapid weight shifting behavior of a rider sitting on an experimental device that imitated a sit-riding type WIP PMV. In the experiment for evaluation of balancing ability, it was revealed that 8 subjects could keep their balance when a rotational stiffness of a seat was 2.45 Nm/deg. In the experiment of the rapid weight-shifting motion, it was confirmed that there was a dead time of about 0.35s from the time when the subjects visually recognized a start trigger signal, and that a reverse reaction motion where the subject’s body was once tilted forward occurred. In addition, it was clarified that the reaction force of the lower limbs against footrest did not affect the behavior of the rapid motion, and that the lower rotational stiffness of the seat might cause the time delay that the weight started to tilt backward. These results can be expected to be useful index when designing inverted driving controller in sit-riding type WIP PMV.

Keywords

• wheel inverted pendulum
• personal mobility
• wheelchair
• rapid weight-shifting
• balancing ability