Abstract:

The primary goal of this research is to do dynamics analysis of a spatial parallel manipulator of four DOF under condition where the friction of
the driver was considered.A complete description of the position and orientation of the moving platform with respect to the reference frame requires four variables.Firstly,
closed form solutions to the input and output were built based on movement
characteristics,and then dynamics equations were built based on Newton-Euler formulation.Then based on three different friction model and cubic polynomial being used for motion planning, for a given motion,the constraining straining forces of each pair and driving
forces of each limp were deduced.The results demonstrate that the friction has obvious
influence on the driving forces.The calculation results show the friction's
impact on driving forces and constraining forces.

Key words: parallel mechanism, friction, dynamics, four degrees-of-freedom(DOF)

摘要：

在考虑驱动摩擦的条件下，对一种四自由度并联机构进行了动力学分析。完全描述该机构动平台的位姿需要4个独立的广义坐标，根据运动特性推导出机构输入与输出的解析表达式，并基于牛顿-欧拉法建立了机构的动力学模型。将3种不同的静态摩擦模型引入各支链移动副，以一种3次多项式为动平台轨迹方程,得到了机构运动副约束反力和各支链驱动力。计算结果显示了摩擦对机构驱动力和运动副约束反力的影响。

关键词: 并联机构, 摩擦, 动力学, 四自由度