Calibration Of Industrial Robot Tool And Workpiece Coordinate System

With the promotion of industrialization process, the development of industrial robots is faster and faster in all areas. In the use of industrial robots, the tool fixed on the end-effector and workpiece were always changed. Tool coordinate calibration determines the accuracy of trajectory planning and workpiece calibration is very important for off-line calibration. Therefore, the research of tool and workpiece calibration has great significance.Around the question of tool coordinate calibration, this paper proposed a tool calibration method based on vision. This paper first elaborated the theory of tool coordinate calibration. Then this paper described the positioning method based on camera space manipulation in detail and did research on the method of establishing the relationship between camera space and robot three-dimensional space, then verified the positioning accuracy based on vision and applied this kind of positioning method to tool coordinate calibration. After that, this paper described the steps of tool calibration experiments based on vision.Around the question of workpiece coordinate calibration, this paper used a workpiece coordinate calibration method based on high precision position sensitive device. This paper first described the theory of workpiece coordinate calibration, and introduced the method of calibration data acquisition under workpiece coordinate and calibration data acquisition under robot base coordinates. Then described the position method based feedback of PSD voltages in detail. Before experimenting, this paper calibrated the laser first and analyzed the convergent of laser intersections after laser calibration. Then this paper elaborated the experiments’ steps of workpiece calibration.According to the methods proposed before, this paper established calibration platform for tool and workpiece calibration, and developed the software syetem. The whole calibration system is a self-calibration system which has high automation. In tool calibration, this paper chose a common tool which looked like the welding torch for calibration experiments. In workpiece calibration, this paper calibrated a cradle head which has DOFs. This paper listed the results of both tool and workpiece calibration, and analyzed the accuracy of calibration. The results verified the feasibility and accuracy of the whole calibration system.