| Serious vibrations always happen to the vehicles in the moving. It is well known that the vertical vibrations in the frequency range of 1-2 Hz may make occupants uncomfortable. If in severe cases, the vibrations may even cause accidents or injuries. In order to evaluate and improve the riding comfort, to study and improve safety protection of occupants, and to realize a "safe and comfortable ride and drive" vision, it is important to establish a simple and effective seated biodynamic model, In the research of the effects of vertical vibration on seated human, establishing an effectively lumped parameter model is considered to be an important method in investigating the effects of conveyance vertical vibration on seated human.In this essay, the modeling, identification and simulation on a wide variety of four-degree-of-freedom (DOF) lumped-parameter models for the seated human were carried out. Firstly, the functions of three evaluation indexes:STH (seat-to-head transmissibility), DPM (driving-point mechanical impedance), AM (apparent mass) are defined by selecting an 18-parameter-four-DOF model as an example. All of the possible 23 types of four-DOF models are listed. The improved version of non-dominated sorting genetic algorithm (NSGA-II), based on the Pareto optimality, is employed to identify the model parameters. Simultaneously, the goodness of fit (ε) is calculated to evaluate the performance of the models. All possible four-DOF models are identified, analyzed and compared in the same above way to get the best-fitted model. Finally, a human-seat-car lumped-parameter model is built using the new model for the vehicle simulation in Simulink. Meanwhile, the dynamic response and RMS of vertical acceleration are calculated to evaluate the simulated performance. The simulated results show that the new model can be successfully applied to the vehicle simulation. The four-DOF model proposed in this essay provides convenience for the vehicle with occupants simulation. |
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