为了分析带有移动末端执行器的柔性机械臂的振动特性，将该系统建模成一个带有移动质量的在竖向平面内作伸缩和旋转运动的柔性悬臂梁。为了方便研究，引入了两个坐标系：随悬臂梁旋转的局部坐标系和固定不动的整体坐标系；结构在局部坐标系下的物理量转化到整体坐标系中，并给出总动能和总势能，利用拉格朗日方程和假设模态法导出了结构的动力学方程；当机械臂以匀速旋转时，系统动力学方程为线性；当机械臂变速旋转时，系统动力学方程为非线性；通过数值算例分析了机械臂和移动末端执行器在不同运动状态下的动力响应；此外还讨论了移动末端执行器和机械臂间的摩擦力对机械臂振动特性的影响。所得结论为相关机器人及其装备的设计提供了理论依据。
Abstract
Robotic arm is widely used in industrial and space exploration.Dynamic analysis of a flexible robotic arm carrying a moving end effector was investigated.The system was modeled as a translating and rotating flexible cantilever beam with a moving mass.For the convenience purpose, two coordinate systems were introduced: a local coordinate system that rotates with the cantilever beam, and a fixed global coordinate system.The physical quantities of the structure in the local coordinate system were transformed into the global coordinate system, and the total kinetic energy and potential energy of the structure were given.Then the equations of the structure were derived by the Lagrange's equation with the assumed mode method.When the robotic arm rotates at a uniform angular velocity the system dynamic equation is linear, while it rotates at a variable angular velocity the system dynamic equation is nonlinear.Finally, the dynamic responses of the robotic arm and the moving end effector under different motion states were analyzed by numerical examples.Moreover, the influences of frictional force on vibration characteristics of the robotic arm were also discussed.The obtained conclusions provide theoretical basis for the design of robots and their equipments.
关键词
机械手臂 /
移动末端执行器 /
轴向运动 /
旋转运动 /
动力学分析
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Key words
robotic arm /
moving end effector /
axially translating /
rotating /
dynamic analysis
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参考文献
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