The Dynamic Characteristics And Crash Safety Investigation Of Electric Bicycle In Driver-vehicle-road Environment

Dynamic characteristic is one of the urgent problems to be solved for the further development of electric bicycle industry, and the safety performance is also increasingly highlighted with the development of electric bicycle. To improve the dynamic characteristics of electric bicycles, the dynamic characteristics and the safety performances of electric bicycles with full vibration reduction system are analyzed in detail in this dissertation by establishing driver-vehicle-road dynamic models. The following research achievements have been completed.Based on 5-DOF dynamic model of the bicycle with two wheels, the 6-DOF model is established through the connection between the flexible link and the main frame and considering the battery as a separate rigid body. The influence rule of the battery mass, the battery position and the connection stiffness between the battery and the frame to the dynamic characteristics of the whole bicycle have been obtained by simulations.With the aid of ANSYS software, the finite element model of the frame with prismatic and revolute is established, and the accuracy of this model is confirmed by modal experiments. Four kinds of main frame models with different cross-section shapes and sizes are established and the influences rule of the main frame's structural characteristics to the dynamic characteristics of the whole bicycles is achieved. The sensitivity analysis is carried out to the thickness of the main frame, which provides an effective method to establish the dynamic characteristics of the whole frame reasonably.On the basis of dynamic analysis and human analysis software, the rigid-flexible coupled dynamic model in the driver-vehicle-road environment is established. Through sinusoidal and trapezoidal road excitations, the influence rule of the frame component flexible, battery, driver mass, vibration reduction system to the dynamic characteristics of the bicycle has been obtained. And the results reveal that these parameters should be considered as important factors in the dynamic design process of electric bicycle.The portable data acquisition system is designed for the dynamic measurement and the road test experiments are carried out. The experimental results verify the effectiveness and feasibility of the rigid-flexible coupled driver-vehicle-road model. The dynamic responses of the electric bicycle are tested in a variety of road environments, which lays foundation for the evaluation of the dynamic characteristics of the electric bicycle.The front-collision simulation model between electric bicycle and the obstacle is established. In this model, the contact between the bicycle and the driver can be adjusted according to the different responses of the driver. Through the front collision analysis with different conditions, the influences of driving speed to the dynamic behavior of the driver are investigated, which lays fundamentals for the study of driver injury in electric bicycle accidents.