一种机器人的平面约束自标定技术研究

Exploring a Planar Constraints Self-calibration Technique of Robots

针对目前基于平面约束的标定方法误差模型复杂、实验条件较为苛刻等问题,提出了一种操作简单的平面约束标定方法。首先提出了修正的末端位置误差模型;其次在标定块的角点上建立坐标系,利用测量头对经过该角点的三个平面分别进行接触式测量,记录接触瞬间的各组关节角度值并将机器人末端位置转换到标定块坐标系中,从而建立平面约束误差模型;另外通过接触式测量头及编程实现了自动化测量,提高了标定效率;最后对运动学参数误差进行辨识并将结果修正到控制器。实验表明,机器人的绝对位置精度有明显提高。该标定方法成本低、效率高、操作简单,在保证精度的前提下简化了误差模型,具有实际应用价值。

Due to the complicated error model or harsh experimental conditions for the current planar constraints calibration of the industrial robot,this paper proposed a new and easily operated planar constraints self-calibration technique.A modified error model of the robot′s manipulator′s end position was set up,and the coordinate system at one corner of the calibration block was established.After recording the joint data of the robot at its touching moment by touching the three planes of the corner in sequence and transforming the manipulator′s end position into the coordinate system,the error model was established.Finally,the kinematic parametric errors was identified and modified into the robot′s controller.The paper realized the automatic measurement by using the touching probe and program developed in the paper,thus enhancing the calibration efficiency.The experimental results show that the positioning accuracy of the robot apparently increases.The self-calibration technique has the advantage of low cost,high efficiency and easy operation.The error model is simplified on the condition that the calibration accuracy is ensured.