Visualization Method Using Probe Bicycle to Analyze Bicycle Rider’s Control Behavior

A bicycle is a useful vehicle in our daily lives, and requires characteristic techniques such as steering control at a constant speed. Since bicycles are commonly used like cars, analyzing their operating condition is essential. Nevertheless, there is little previous research that has succeeded in designing a low-cost method to analyze the operating condition. In the current study, we present a more reasonable model of the visualization of bicycle control behavior using two-dimensional (2-D) plots. In the model, four steps are taken: 1) acquire sensor information from the bicycle, 2) calculate the movement trajectory of the front and rear wheels using the bicycle equations, 3) derive the rotation center, and 4) extract the 2-D plots. As a result, it was possible to visually anticipate 1) a rider's control from the curvature center and trajectory of the front-wheel and 2) the actual behavior and its quality from the rear-wheel. Since it requires accurate speed, steering angle, and body tilt angle to calculate the movement trajectory, we designed a special probe bicycle that could directly obtain these parameters. By using this probe bicycle, four points were clarified. 1) At turning, the bicycle rider sets a target turning center, which is the center of turning. 2) An I-shaped rotation center trajectory appears when the bicycle is going straight, and a V-shaped rotation center locus appears when turning. 3) The distribution trend of the curvature center differs greatly between the front and rear wheels. 4) The quality of turn can be evaluated by the distribution trend. The 2-D plots enabled us to observe the quality of the rider's control like an X-ray.