汽车八自由度模型动态仿真研究

汽车振动系统是一个非常复杂的系统. 为达到准确反映整车振动情况，基于一定假设，在Matlab软件中利用牛顿法建立某汽车八自由度振动模型. 分析整车动态时域响应特性，基于滤波白噪声和二阶Pade算法，建立四轮相关路面模型. 验证路面精确度，并将其作为激励输入整车振动模型，利用Newmark显式积分法进行求解，将各响应量时域信号转化为频域响应信号并与该振动系统的频域仿真对比. 结果证明该模型的可靠性好，求解速度快. 进一步研究车身质心位置、悬架刚度、轮胎刚度和悬架阻尼等因素对驾驶员与车身质心处舒适性的影响，并基于原车参数提出改善整车舒适性的建议.

Research on Dynamic Simulation of Eight Degrees of Freedom Automobile Model

The vehicle vibration system is a very complex system. In order to accurately reflect the vibration of the whole vehicle, based on certain assumptions, the eight degrees of freedom vibration model for a car was established by using Newton method in Matlab software. Based on the analysis of vehicle dynamic response characteristics in time domain, a four-wheel correlation road model was established based on filtered white noise and the second-order Pade algorithm. The accuracy of the road surface was verified, and it was used as the excitation input to the vehicle vibration model. The Newmark explicit integration method was used to solve the problem. The time-domain signal of each response was transformed into the frequency-domain response signal, and compared with the frequency-domain simulation of the vibration system. The results show that the model has good reliability and fast solution speed. Furthermore, the influences of the position of body mass center, suspension stiffness, tire stiffness and suspension damping on the comfort of driver and body centroid were further studied. Based on the original vehicle parameters, suggestions for improving vehicle comfort were put forward.