Research on Vision Calibration Method of the Pitch Axis Position
BI Chao,ZHAO Yuan,HAO Xue,FANG Jian-guo
Aviation Key Laboratory of Science and Technology on Precision Manufacturing Technology, Beijing Precision Engineering Institute for Aircraft Industry, Beijing 100076, China
Abstract With regard to the calibration difficulty of pitch axis positions in the five-axis vision measuring system for film cooling holes, a new calibration method based on industrial camera and specially designed target was proposed. During the implementation of the method, a cuboid metal block with sharp and intact edges was applied as the calibration target. In the calibrating procedure, the target was placed at different positions and postures by the rotations of the pitch axis. Afterwards, the industrial camera focused on the surfaces of the target in different situations and then captured the images of the same goal edge on the front surface and upper surface respectively. According to the constraint condition established by the uniqueness of the goal edge extracted from those images, spatial position of the pitch axis in the measuring space denoted by O-XYZ would be calculated by solving simultaneous equations. At last, to verify the calibration method and results, a test piece was measured 10 times by the system after pitch axis position calibration, whose nominal size was 60mm. As shown in the inspecting experiments, the limit errors of single measurement of the length dimension were ±0.0216mm, and the measuring errors of those experimental results were all smaller than ±0.012mm, which manifested the feasibility and effectiveness of the calibration method proposed.
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2022, Vol. 43 
