• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2022, Vol. 58 ›› Issue (14): 170-180.doi: 10.3901/JME.2022.14.170

• 特邀专栏:大型构件视觉测量与机器人加工 • 上一篇    下一篇

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基于迁移学习的铣削机器人定位误差补偿方法

邓柯楠, 高栋, 马守东, 路勇   

  1. 哈尔滨工业大学机电工程学院 哈尔滨 150000
  • 收稿日期:2021-05-31 修回日期:2021-12-10 出版日期:2022-07-20 发布日期:2022-09-07
  • 通讯作者: 路勇(通信作者),男,1971年出生,博士,教授,博士研究生导师。主要研究方向为智能刀柄、加工过程监控与大型构件加工。E-mail:luyong@hit.edu.cn
  • 作者简介:邓柯楠,男,1992年出生,博士研究生。主要研究方向为大型构件移动机器人加工理论与方法。E-mail:1110801922@hit.edu.cn;高栋,男,1970年出生,博士,教授,博士研究生导师。主要研究方向超大构件加工方法,重型机床加工误差补偿。
  • 基金资助:
    国家重点研发计划资助项目(2018YFB1306800)。

An Efficient Error Compensation Method for Milling Robot Based on Transfer Learning

DENG Kenan, GAO Dong, MA Shoudong, LU Yong   

  1. School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150000
  • Received:2021-05-31 Revised:2021-12-10 Online:2022-07-20 Published:2022-09-07

摘要: 空间网格补偿法是提高机器人定位误差的有效方法之一,然而由于所需采样位姿多导致误差测量环节非常耗时,为提高机器人定位误差补偿效率,提出了一种机理分析与数据驱动的铣削机器人定位误差补偿方法,基于迁移学习来预测机器人工作空间内不同区域的定位误差。首先建立机器人刚柔耦合误差模型,研究立方体与柱体工作空间内不同区域的误差分布特性;之后,考虑误差区域相似性将机器人工作空间分为源域空间与目标域空间,在源域空间基于分级采样策略将完备的机器人采样位姿及误差测量数据作为源域数据,对于目标域空间只需要将少量的采样位姿及误差数据作为目标域数据,源域数据与目标域数据均用于训练高斯过程回归模型,通过基于加权拟合误差的子空间对齐和自适应权重迭代方法提升迁移学习模型预测精度,根据指定机器人位姿参数预测并补偿机器人定位误差;最后,使用KR160铣削机器人系统进行了误差补偿试验以验证该方法的可行性和有效性,试验结果表明,经过补偿后机器人定位误差1.499 mm降低到0.182 mm,所需机器人采样位姿数目减少了70%,使用铣削机器人加工法兰孔,其轮廓误差和位置误差达到0.269 mm和0.331 mm,该方法可以提高补偿效率和机器人定位精度。

关键词: 定位误差, 迁移学习, 铣削机器人, 补偿效率, 耦合误差模型

Abstract: The grid compensation is one of the effective methods to improve the positioning accuracy of industrial robot. However, error measurement is time-consuming due to the many sampling robot configurations required. To improve positioning error compensation efficiency, proposes a mechanism analysis and data-driven method for milling robot, which predict the positioning error of different regions in the robot workspace based on transfer learning. Firstly, the rigid-flexible coupling error model of the robot is established, and the similarity of the error distribution in different regions of the cube and cylindrical workspace is analyzed. Then, the robot workspace is divided into source domain and target domain by considering error similarity of different areas. Complete robot sampling configurations and errors measurement data are obtained by hierarchical sampling method as source data for the source workspace, and only a few robot configurations are required to measure the positioning errors as the target data for targe regions. The source domain data and target domain data are used to train the Gaussian process regression model (GPR). The prediction accuracy of the transfer learning model is improved by subspace alignment and adaptive weight method based on weighted fitting error. The robot positioning error is predicted and compensated according to the robot positions. Finally, a KR160 milling robot is used for error compensation experiments to verify the feasibility and effectiveness of the proposed method. The experimental results prove that the robot positioning error is reduced from 1.499 mm to 0.182 mm after compensation, and the number of robot sampling poses is reduced by 70%, the contour error and position error of the flange hole are 0.269 mm and 0.331 mm, which proves that the method can improve the compensation efficiency and machining accuracy.

Key words: positioning errors, transfer learning, milling robot, compensation efficiency, coupling error model

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