IDENTIFICATION OF THE BIOMECHANICAL PARAMETERS OF THE RIDERS OF TWO-WHEELED VEHICLES BY MEANS OF VIBRATION TESTING

In bicycles and motorcycles the mass of the rider is a relevant share of the total mass and the passive response of the rider’s body to vibrations influences the dynamics and stability of the whole system. Therefore advanced models of twowheeled vehicles have to include a passive biomechanical model of the rider. This paper focuses on the development of biomechanical models able to simulate the response of the rider to yaw and steer oscillations and on the identification of the rider’s body mechanical properties. Rider models composed by some rigid bodies with lumped stiffness and damping elements in the articulations are developed. The inertial properties of the rider’s model are calculated from anthropometric data. The stiffness and damping properties are obtained from laboratory tests in which the rider rides a motorcycle mock-up driven by a hydraulic shaker generating yaw oscillations. The responses of the districts of the human body are measured by means of rate gyros and the frequency response functions (FRFs) between the measured angular velocity and the enforced angular velocity are calculated. The tests are carried out both with the hands on the handle-bar of the motorcycle mock-up and with the raised hands. Biomechanical parameters are identified by means of best fitting techniques. Experimental results relative to 5 riders are presented and the identified biomechanical parameters are discussed. The proposed biomechanical models make it possible to calculate the rider’s response to steer oscillations as well, some results are presented.