Rider control identification in bicycling using lateral force perturbation tests

A model describing rider control while steering and stabilizing a bicycle has been developed. Experimental data were obtained from riding a bicycle on a narrow treadmill while perturbing balance with impulsive forces at the seat post. The experiments were conducted at 2–7 m/s covering both the stable and the unstable forward speed range. Bicycle and rider mechanics have been modeled using the Whipple bicycle model extended with the rider inertia. A rider control model applying steering torque at the handle bars has been developed exploring potential feedback of visual, vestibular and arm proprioceptive cues. The identified rider control parameters, after model reduction, stabilize the system and mimic realistic rider control behavior. The feedback gains of this control model were used to identify the specific optimal control linear-quadratic regulator (LQR) cost function which the rider was using to control the bicycle. The identified cost functions indicate that at low speed the rider minimizes his control effort and at high speed he minimizes the heading error.