坐姿人体侧向振动试验、建模与参数识别

Test,Modeling and Parameter Identification of Seated Human Body Exposed to Lateral Vibration

坐姿人体侧向振动属于全身振动的范畴,影响乘坐舒适性。针对坐姿人体在低频、大幅度激励下的侧向振动特性研究不足的问题,通过振动实验与力学模型相结合的方法,对坐姿人体进行了侧向振动试验、建模和参数辨识研究。研制了曲柄-滑块式振动试验台架,采用0.5~8.0 Hz之间的单频激励,对10名21~28岁之间的青年志愿者进行了侧向振动试验,采用微型航姿参考系统测量了座椅踏板、坐姿人体上、下体的侧向加速度,得到了座椅脚踏板至上体和下体的传递特性数据;将坐姿人体视为上、下两个刚体,建立了表达坐姿人体侧向振动的二自由度生物力学模型,推导了传递特性的表达式;以相对误差平方和为目标函数,采用遗传算法对试验数据进行拟合,辨识了模型刚度、阻尼参数,并引入拟合度来评价模型拟合效果。研究结果表明:志愿者上体侧向主共振频率在2.4~3.1 Hz,下体在2.4~3.2 Hz,并且上体在5 Hz以后存在比较明显的二阶共振;上体传递率幅值在1.45~1.89之间,下体在1.53~2.38之间;下体共振频率比上体略高,振动更剧烈;提出的二自由度模型能够较准确地对坐姿人体侧向振动特性进行描述。

Lateral vibration of seated human bodies belongs to the category of whole-body vibration,which affects ride comfort.Aiming at the problem of insufficient research on the lateral vibration characteristics of seated human bodies under low-frequency and large-amplitude excitation,through the combination of vibration experiment and mechanical model,the lateral vibration experiment,modeling and parameter identification of the seated human bodies were studied.A crank-slider vibration test bench was developed.Lateral vibration experiments under single-frequency excitation from 0.5 to 8.0 Hz were carried out on 10 young volunteers with the ages of 21~28.Micro attitude reference systems were used to measure the lateral accelerations of the seat pedal,the upper and lower body of the seated human bodies,and the transmission characteristic data from the seat pedal to the upper and lower body were obtained.Considering the seated human body as two rigid bodies,a biomechanical model with two degree-of-freedoms expressing the lateral vibration of the seated human body was established,and the expression of transmission characteristics was deduced.Taking the sum of squares of relative errors as the objective function,the test data were fitted by genetic algorithm,the model stiffness and damping parameters were identified,and the fitting degree was introduced to evaluate the fitting effect of the proposed model.Research results show that the lateral main resonance frequency of the volunteers'upper body is 2.4~3.1 Hz and that of the lower body is 2.4~3.2 Hz;moreover,the upper body has obvious second-order resonance over 5 Hz.The amplitude of upper body transmissivity is 1.45~1.89,and that of lower body is 1.53~2.38.The resonance frequency of the lower body is slightly higher than that of the upper body,and the vibration is more intense.The proposed biomechanical model with two degree-of-freedoms can accurately describe the lateral vibration characteristics of the seated human body.