Research on coaxiality measurement system of large-span small-hole system based on laser collimation

• Published in: Measurement : journal of the International Measurement Confederation Vol. 191; p. 110765
• Main Authors: Gao, Cheng, Lu, Yonghua, Lu, Zhengwei, Liu, Xinyu, Zhang, Jinhai
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 15.03.2022; Elsevier Science Ltd
• Subjects: Algorithms; Apertures; Coaxiality; Collimation; Diameters; Error analysis; Large-span small-hole system; Laser collimation; Laser displacement sensor; Lasers; Measurement errors; Non-contact measurement; Position sensing; PSD; Sensors; PSD; Large-span small-hole system; Non-contact measurement; Laser collimation; Coaxiality; Laser displacement sensor
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2022.110765

•This system is mainly aimed at the coaxiality measurement of large-span small-hole system.•The system realizes the establishment of reference axis for non-reference parts at any position in space.•The internal contour information of the small hole is obtained by the laser displacement sensor.•The system uses the least squares method and PSO algorithm to obtain the coaxiality error.•It has been verified by tests that the system has high measurement accuracy. Aiming at the problems of large-span small-hole system, such as long spatial span, small measured aperture, short hole depth, large distance between adjacent holes, limited measurement space, and lack of measurement benchmark, a non-contact coaxiality measurement system based on laser collimation with the laser displacement sensor as the core is proposed. According to the mathematical model, a position sensitive detector(PSD) and a motion platform with multiple degrees of freedom are utilized to establish a reference axis for parts at any position. Also, the relevant cross-section circle fitting and coaxiality evaluation algorithms are designed to solve the measurement problem. It is proved that this system has high coaxiality detection accuracy for the parts with large axial dimensions (total length is more than 1500 mm), small aperture (diameter is less than φ 10 mm) and large hole spacing (space between two holes is more than 750 mm), and the measurement error does not exceed 0.03 mm.