基于ADAMS的理想铰约束模型的局限性研究

针对在多体系统动力学分析中采用理想铰约束模型模拟关节轴承的铰接功能引起仿真结果出现偏差的问题,以基于虚拟样机技术的组合臂架式门座起重机变幅过程的动力学分析为例,将其中的两个主要铰接点视为含间隙的滑动轴承,运用含间隙矢量模型、非线性连续接触碰撞力的混合模型和修正的库仑摩擦模型,综合考虑铰链间隙、接触变形和摩擦等因素的影响,求解了系统在典型工况下的动力学响应,并与按照理想铰约束模型得到的响应结果进行对比,揭示了理想铰约束模型存在的局限性,为如何在工程机械动力学分析中合理使用理想铰约束模型提供了参考。

Research on the Limitations of ADAMS-based Ideal Hinge Constraint Model

In order to overcome the difficulty to properly evaluate the errors resulted from the idealized joint constraint model which is used to simulate the hinge function of joint bearings when performing multi body system dynamic analysis, an effort was presented to quantitate the errors through observation of the changes that the idealized joint constraint model was replaced by a type of more accurate revolute joint model.The dynamic analysis of the luffing process of a gantry crane four bar linkage arm system was taken as the example to demonstrate the application of the developed models for comparison. Two main joints in the mechanism were provisionally treated as sliding bearing with clearance and the developed revolute models which were different from the idealized joint constraint model included a general vector model, a continuous hybrid contact model and an improved Columb friction model. The effects of joint clearance, contact deformation and friction were comprehensively taken into account in the new model and the system dynamic responses with these two joint models in the same typical working conditions were obtained and compared. The comparison clearly reveals some limits of the idealized joint constraint model, which may provide essential assistance for engineering machinery designers to reasonably use the idealized joint constraint model.