This paper investigates by means of a mathematical model and running experiments how a rider controls a motorcycle while performing lane change, and proposes a rider model which reproduces the difference in riders' control patterns shown in the running experimental results.
The mathematical model of the motorcycle used here is a linear model having four degrees of freedom i.e. side slip, yaw, roll, and steering. The rider model consists of the upper body and the lower body, and the former has a degree of freedom for roll, and the latter has a degree of freedom for the lateral direction.
The running experiments of lane change were carried out as follows. In the experiments, five motorcycles with a displacement of 250 cc to 750 cc were used, and the lane changes were performed by 24 skilled riders.
The following results were obtained from the study on the running experiments and the simulations used by the mathematical model. In this running of lane change, the rider's steering pattern is mainly divided into two: smooth steering pattem and sharp steering pattern. The difference betweent he two is mainly basedo n the characteristic of the individual rider. The control of lane change is mainly performed by the steering torque. If the control by the steering torque is assisted by the control of the rider lower body torque, the lane change behaviour can be quickened as compared with only steering torque control.