基于平行机构约束链的三轴联动平台误差分析与建模

Geometrical Error Analysis and Modeling of 3-Axis Simultaneous-Motioned Platform Based on the Parallel Mechanism Constraint Chain

并联机器人中的约束链处于从动地位,由约束链产生的误差很难消除,直接影响到整个机构的运动精度,研究约束链误差对并联机器人整体误差的影响具有重要意义。以设计的三轴联动平台为例,分析了具有平行机构约束链的机构误差问题,建立了平行机构约束链误差数学模型。通过实例分析可以看到,具有平行机构的约束链转角误差和杆长对终端误差影响较大,误差是随交角变化的函数,由此可以找到误差最小的姿态。

The constraint chain of parallel robot is in a driven position. It is difficult to eliminate the constraint chain error which directly impacts on the kinematics precision of the whole structure. To analyze the constraint chain error is significant for parallel robot error. Taking 3-axis simultaneous-motioned platform for example, we analyze parallel mechanism constraint chain geometrical error and set up its math model. By sample analysis, we can conclude that the kinematics error of the parallel mechanism is greatly influenced by rod length and comer error and it changes along with cut angle. The minimum error of position and nose could he found.