A Vision-Based Self-Calibration Method for Robotic Visual Inspection Systems

Sensors

Shibin Yin²  Yongjie Ren¹  Jigui Zhu²  Shourui Yang² 

[1] State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China;

关键词: self-calibration;    industrial robot;    visual sensor;    TCP;   

DOI  :  10.3390/s131216565

来源: mdpi

【 摘 要 】

A vision-based robot self-calibration method is proposed in this paper to evaluate the kinematic parameter errors of a robot using a visual sensor mounted on its end-effector. This approach could be performed in the industrial field without external, expensive apparatus or an elaborate setup. A robot Tool Center Point (TCP) is defined in the structural model of a line-structured laser sensor, and aligned to a reference point fixed in the robot workspace. A mathematical model is established to formulate the misalignment errors with kinematic parameter errors and TCP position errors. Based on the fixed point constraints, the kinematic parameter errors and TCP position errors are identified with an iterative algorithm. Compared to the conventional methods, this proposed method eliminates the need for a robot-based-frame and hand-to-eye calibrations, shortens the error propagation chain, and makes the calibration process more accurate and convenient. A validation experiment is performed on an ABB IRB2400 robot. An optimal configuration on the number and distribution of fixed points in the robot workspace is obtained based on the experimental results. Comparative experiments reveal that there is a significant improvement of the measuring accuracy of the robotic visual inspection system.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.