Evaluation of Riding Instability of a Bicycle with Children as Passengers Using the Relationship Between Handlebar Angle and Roll Angle

This paper proposes indices to evaluate the riding instability of bicycles of riding children together. We propose two indices that focus on the relationship between handlebar angle and roll angles and discuss the advantages and disadvantages of each index. The experimental data of bicycles in various conditions were used to investigate the characteristics of each index, and the relationship between the proposed index and subjective feelings of riding instability was also investigated. The results showed that the evaluation of riding instability using singular spectral transformation, which focuses on the change in the relationship between handlebar angle and roll angle, can evaluate the difficulty of driving caused by riding with children together on the paved road. The handlebar roll ratio, which evaluates the independent swing of the handlebar angle, was found to be appropriate as an index to evaluate the difficulty of handlebar operation. It was also found that the handlebar roll ratio is an index that also reflects the disturbance of bicycle behavior due to habituation of operation and the influence of the road surface.