铰接摆杆式大功率拖拉机单边越障动态特性仿真分析

Dynamic Characteristics of Large Wheel Tractor with Hinge Swing Link during Unilateral Obstacle Surmounting

根据铰接摆杆式大功率拖拉机整机结构,建立8自由度多体动力学仿真模型。结合农田作业中出现的单边越障情况,基于欧拉四元数,利用含拉格朗日乘子的增广矩阵法建立了动力学方程。运用Matlab软件对空间多体动力学仿真进行编程。在纵向、侧向,轮胎简化为动态参数的串联弹性阻尼元件。用迭代法求解轮胎和动压反馈装置油缸的作用方程以获得相应的作用力与拖拉机构件的形位和速度的非线性关系。通过数值仿真分析,得到了该工况下整机载荷和振动频率。研究表明,在产品设计阶段应充分考虑侧向和横摆加速度的影响,采用动压反馈装置的液压转向系统可减少整机振动并提高转向安全性。

According to the structural characteristics of frame of large wheel tractor,a spatial mechanism multi-body system model with eight degree of freedoms was set up.In order to obtain solutions of multi-bodies dynamic simulation,the augmented formulation based on Euler 4 parameters was set up and simulation programs of multi-body dynamics were developed with help of Matlab software.The elasticity of tires in longitudinal and lateral direction was described with a spring-damper element of variable parameter in series.In the program the iteration equations of the tires functions and hydraulic cylinders functions with a dynamic pressure feedback network were calculated to reveal the nonlinear relations between the force with displacement and velocity of the tractor bodies.Multi-body dynamics simulation of the model was carried out to obtain dynamical loads and vibration frequency.The adaptive ability to environment and safety of steering could be improved by using a dynamic pressure feedback network in hydraulic system of steering.