An automated method to calibrate industrial robots using a virtual closed kinematic chain
An automated method to calibrate industrial robots using a virtual closed kinematic chain
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DOI：
10.1109/tro.2007.909765
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发表时间：
2007-12-01
影响因子：
7.8
通讯作者：
Starr, Greg
中科院分区：
文献类型：
--
作者：
Gatla, Chandra Sekhar;Lumia, Ron;Starr, Greg
本文介绍了一种工业机器人标定算法--虚拟闭合运动链法。当前的机器人运动学校准方法使用末端执行器的位置和取向的测量。这些测量的准确性受到测量设备分辨率的限制。在所提出的方法中，激光指针工具，连接到机器人的末端执行器，针对一个恒定的，但未知的位置在一个固定的对象，有效地创建一个虚拟的7自由度封闭的运动链。结果，末端执行器的位置和取向的小变化在远处物体上被放大。因此，提高了观测的分辨率，增加了校准机器人所需的关节角度测量的精度。仿真和真实的实验均验证了该方法的有效性。它还表明，在模拟中，该方法可以自动化的反馈系统，可以在真实的时间实现。机器人的精度后，使用建议的校准程序进行测量，针对任意固定点，并测量的平均值和标准偏差的投影点的扩散半径。扩散半径的平均值和标准差分别从5.64和1.89 mm提高到1.05和0.587 mm。
This paper describes an industrial robot calibration algorithm called the virtual closed kinematic chain method. Current robot kinematic calibration methods use measurements of position and orientation of the end effector. The accuracy of these measurements is limited by the resolution of the measuring equipment. In the proposed method, a laser pointer tool, attached to the robot's end effector, aims at a constant but unknown location on a fixed object, effectively creating a virtual 7 DOFs closed kinematic chain. As a result, small variations in position and orientation of the end effector are magnified on the distant object. Hence, the resolution of observations is improved, increasing the accuracy of joint angle measurements that are required to calibrate the robot. The method is verified using both simulation and real experiments. It is also shown in simulation that the method can be automated by a feedback system that can be implemented in real time. The accuracy of the robot after using the proposed calibration procedure is measured by aiming at an arbitrary fixed point and measuring the mean and standard deviation of the radius of spread of the projected points. The mean and standard deviation of the radius of spread were improved from 5.64 and 1.89 mm to 1.05 and 0.587 mm, respectively.