摘要
地面长臂机械研究中一般都将铰当成理想铰处理而忽略铰间隙的影响,为得到更符合实际运动学规律和动力学特性的结果,首先,采用Lankarani-Nikravesh模型并选取合适的摩擦因数,分析加入第1节臂和加入全部4节臂油缸连接旋转铰间隙接触摩擦的影响;其次,建立对应的多柔体臂架的刚柔混合模型,对理想铰和铰间隙臂架模型的末端轨迹和振动特性进行数值分析。结果表明:加入铰间隙模型的末端振动位移比理想铰模型的末端位移增大,第1节臂液压油缸最大受力值也对应增大;考虑铰弹性的第1阶固有频率比理想铰模型有所降低,证明此类机械铰间隙的影响不能忽略。最后,通过臂架实验台验证了模型的合理性和数值仿真的正确性,为此类机械设计和工程应用提供参考。
The long manipulator of ground machinery is typical multi-body system,the existing research on the kinematic relationship and dynamic characterization are generally concerned on the flexible booms with the ideal joint whereas the dynamics of joint clearance isn′t ignored.Firstly,a flexible multi-body boom model is established.Then,the first cylinder and boom joint clearance is considered.Next numerical simulation is done on the tip trajectory and vibration characteristic of ideal and clearance joint models.The simulation results show that the tip displacement of the flexible multi-body model with joint clearance is larger than that of ideal joint model.Meanwhile the hydraulic cylinder force also increases.And the first natural frequency is lower than that of ideal joint model.Finally an experiment is done on a flexible multi-body boom structure.The result provides a design reference for such machinery.
出处
《振动．测试与诊断》
EI
CSCD
北大核心
2015年第3期563-567,共5页
Journal of Vibration,Measurement & Diagnosis
基金
国家基础研究发展计划("八六三"计划)资助项目(2008AA042802)
关键词
多柔体
机械臂
铰间隙
动力学
固有频率
flexible multibody
manipulator
joint clearance
dynamic
natural frequency
