含区间铰间隙柔性机械臂控制精度分析

为了分析大变形、间隙碰撞和不确定性对机械臂动力学特性和控制精度的影响,提出了含区间铰间隙的柔性机械臂动力学建模方法和该动力学模型的求解方法.模型中采用绝对节点坐标法对柔性部件进行动力学建模,采用混合碰撞力模型和Ambrósio摩擦力模型建立关节铰间隙,并且采用区间变量描述间隙尺寸和部件杨氏模量.通过数值仿真分析表明:部件柔性和间隙会显著地影响机械臂动力学特性和控制精度,而且随着部件弹性模量减小、间隙尺寸增大,影响将更加显著;考虑不确定性时,机械臂的控制精度将降低,而且参数不确定性会显著影响该机械臂的动力学特性.

Tracking accuracy analysis of a flexible manipulator with interval joint clearance

To investigate the influences of large deformation, clearance and uncertainty on the dynamic behavior and control accuracy of a manipulator, a method for establishing the dynamics model of a flexible manipulator with interval joint clearance is presented. Then an evaluation method for the dynamics model is proposed. In this work, the absolute nodal coordinate formulation is used to model the flexible components, and the hybrid contact force model and Ambrósio friction force model are applied to constructing the revolute clearance joint. Meanwhile, intervals are used to characterize the clearance size and Young''s modulus. The simulation results show that the flexibility and clearance can obviously affect the dynamic behavior and control accuracy of the manipulator. In addition, the influence will be more significant as the Young''s modulus decreases or the clearance size increases. Uncertainty can reduce control accuracy and significantly affect the dynamic behavior of the manipulator.