基于多体动力学研究的理论和方法，利用MATLAB和ADAMS软件分别建立JS-754拖拉机振动的数学模型和机械模型，进行随机振动和脉冲输入的平顺性仿真分析。数学模型包括利用拉格朗日第二方程建立拖拉机3自由度振动模型，从轮胎动态特性出发，建立拖拉机整车—轮胎耦合系统；机械模型借助虚拟样机技术对JS-754拖拉机整车实体建模，并定义整车各个部件约束关系。仿真结果表明，JS-754拖拉机在D级路面下座椅处垂向加速度均方根值为0.3909 m/s2，脉冲激励输入下座椅处垂向加速度最大响应小于34.59 m/s2。仿真得到轮胎特性随车行驶时变化曲线，座椅处振动频率的范围集中在3-5 Hz。研究表明，JS-754拖拉机平顺性较好，提出的拖拉机振动建模方法具有较强的参考价值，可为拖拉机以及其他非道路车辆平顺性的研究提供理论依据和建模思路。%Based on the theory and method of multi-body dynamics study, the mathematical and mechanical vibration model of JS-754 tractor was established using MATLAB and ADAMS software. The ride comfort of the tractor was simulated with the input signals of random vibration and pulse. The mathematical model consists of 3 degrees of freedom vibration model of tractor using the second equation of Lagrange. From the dynamic characteristics of the tire, a tractor vehicle tire coupling system was established. The mechanical model of JS-754 tractor was established by virtual prototyping technology, and the relationship between the various parts of the vehicle was deifned. Simulation results showed that vertical Root-Mean-Square (RMS) acceleration was acquired which equals 0.390 9 m/s2 on D grade road and the maximum response of the vertical vibrational acceleration velocity was less than 34.59 m/s2 on the seat. The signal of tire characteristics with the tractor driving was obtained, the frequency range of vibration was concentrated between 3 and 5 Hz on the seat by simulation. The research shows that the ride comfort of JS-754 tractor is good. The proposed method of tractor vibration modeling is of great reference value, and it can provide the theoretical basis and modeling ideas for the research on the ride comfort of the tractor and other non-road vehicles.
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