Research On Vibration Performance Of Lumped Parameter And Multi-body Coupling Human-seat-vehicle Model

Vehicle ride comfort is an important standard for evaluating vehicle performance,which directly affects the health and safety of drivers and passengers.At present,the research on vehicle ride comfort is mainly to couple the human sitting biodynamic model with the vehicle model to analyze the influence of different driving environment and vibration factors on human vibration response.In this paper,two modeling methods of human sitting biodynamic model were studied.The model was coupled with the vehicle model respectively.The time domain and frequency domain responses of the human-seat-vehicle system vibration model were analyzed.The vehicle ride comfort was evaluated by calculating the RMS value of human body weighted acceleration,and the vibration test of human-seat-vehicle system was carried out.The main research work of this paper is as(1)The human sitting posture model was studied by using lumped parameter and multi-body dynamics modeling method respectively.A five-degree-of-freedom human sitting posture lumped parameter model was established.Considering the influence of AM,DPMI and STH,the genetic algorithm was used to identify the parameters of the model to obtain all the parameters of the model.By calculating the goodness of fit,it was found that the model can better fit the experimental data than other models.The modal analysis of Kim’s multi-body dynamic model of human sitting posture was carried out by using multi-physics simulation software COMSOL.The human motion posture affecting the resonance frequency in the frequency range of 0～10 Hz was obtained,and the vertical and vertical transfer function responses of each mass part of the human body in the human-seat system were further analyzed.(2)The human-seat-vehicle system model simulation analysis was carried out.The four-degree-of-freedom half-car model was selected for research,and the frequency response characteristics of the suspension system were analyzed.Taking the time-domain model of filtered white noise pavement as input,the lumped parameter model of human sitting posture and the multi-body dynamics model were coupled with the vehicle-seat system respectively.The time-domain and frequency-domain acceleration responses of human in vertical and longitudinal directions under different road grades and vehicle speeds were obtained.(3)Vehicle ride comfort evaluation.According to the evaluation method provided by ISO 2631,the RMS values of the weighted acceleration of human head and buttocks in vertical and longitudinal directions were calculated.The simulation results showed that ride comfort is affected by road grade and vehicle speed.Compared with the change of vehicle speed,the change rate of the RMS value of the weighted acceleration of the human body caused by the change of road grade is higher.The two proposed vibration models of human-seat-vehicle system could accurately calculate the vibration response of sitting human body,which was helpful to evaluate the ride comfort of vehicle.(4)The vibration response test of human-seat-vehicle system was carried out.The low-frequency three-way vibration test of the human-seat system was carried out by using the six-degree-of-freedom motion test platform.By applying the sinusoidal wave excitation in different directions within the frequency range of0.5～5 Hz,the acceleration signal and excitation signal of the human head were measured,and the dynamic transfer function curves of the human-seat system in the transverse,longitudinal and vertical directions were obtained.The vibration response test of the human-seat-vehicle system under random road excitation was carried out,and the acceleration response of the human head at the speed of 40,60 and 80 km/h under B-grade road surface were obtained.