We investigate the steady-state handling of a bicycle as the means to explore the major factors governing the manoeuvrability and handling characteristics of a rider/bicycle system. Steady-state handling arises when the rider/bicycle negotiates a constant radius turn at constant speed and lean. Employing a bicycle instrumented to measure steering torque, steering angle, bicycle speed, bicycle acceleration, and bicycle angular velocity, we report data for 108 trials. The trials include two subjects executing steady turns of six different radii, at three speeds, and with three rider lean conditions. We introduce a model for the steady-state handling of the bicycle/rider system that accounts for rider lean and compare the experimental data to the model predictions. We find that the model, with idealized tire parameters, explains 97.0% of the variability in the measured bicycle roll angle, 99.6% of the variability in the measured steering angle, and 88.8% of the variability in the measured steering torque. Using more realistic tire parameters yields little difference in the model predictions. Both the model and the data demonstrate that rider lean (lateral shifting of the bicycle/rider center of mass) strongly influences the steering torque/lateral acceleration ratio, suggesting that rider lean plays an important role in the control of a bicycle. By contrast, the steering angle/lateral acceleration ratio is largely insensitive to rider lean, suggesting that using the steering angle as a cue for bicycle control is advantageous over using steering torque. (Author/publisher) For this paper, other papers and posters presented at this Symposium see http://bicycle.tudelft.nl/bmd2010/
Abstract