An Effective Coaxiality Measurement for Twist Drill Based on Line Structured Light Sensor

Aiming at the demand of rapid detection for coaxiality of crankshaft journal, a method of visual measurement of coaxiality error based on 3D point cloud is proposed. In this research, a laser scanner is utilized to obtain a 3D point cloud model of the part to be measured, and a circular method of rotary cutting is put forward to obtain equally spaced optimal slices of the journal. The center of the slice is then obtained using the Pratt circle fitting method optimized in this paper. After that, the center of the slice is used to obtain the common reference axis using the least squares method, which finally realizes the measurement of the coaxiality error. The experimental results show that the proposed method of getting the slices is more accurate, the maximum absolute error of the circle fitting method compared with the results of the coordinate measuring machine (CMM) is no more than 4.2 μm, and the maximum absolute error of the coaxiality detection results and the results of the CMM is 5.5 μm, which can satisfy the practical needs of fast and efficient measurement of the coaxiality error of crankshafts.

Section: Prefacementioning

confidence: 99%

Research on the measurement method of crankshaft coaxiality error based on three-dimensional point cloud

Dou,

Zheng,

Ren

et al. 2023

“…As a practical and powerful non-contact method for shape measurement, optical 3D measurement techniques have been widely employed in applications such as heritage preservation, reverse engineering, industrial design, and inspection [1][2][3][4][5]. Active optical 3D measurement technique projects the * Author to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

“…According to the different methods of phase recovery, FPP is usually subdivided into two categories: one category calculates the phase through the process of Fourier transform, frequency domain selection, and inverse Fourier transform, which is called Fourier transform profilometry [11,12]; the other category calculates the phase through the phaseshift algorithm, which is called phase-shifting profilometry [13]. One of the most extensively used and cost-effective linestructured light methods is triangulation laser scanning [1][2][3]. Benefiting from the concentrated and stable energy characteristics of laser beams, numerous studies have demonstrated the capability of triangulation laser scanning systems to reconstruct the surfaces of samples in various complex scenarios, including surfaces with different outside lighting conditions, materials, and textures [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Mirror-assisted 360° panoramic 3D measurement system based on rotary laser profilometer

Yao,

Han,

Zhou

et al. 2024

The full surface digitization of real samples plays a crucial role in fields such as object recognition, industrial quality control, and reverse modeling. To achieve panoramic three-dimensional (3D) reconstruction of samples in complex scenes, we propose an advanced panoramic laser scanning system, consisting of a laser rotation scanning system and a pair of plane mirrors. With the assistance of mirrors, the projected line laser beam can illuminate the sample from full angles in a single scanning sequence, and the camera can capture the 3D information of the sample from several specific viewpoints. The scanning method of rotating allows us to achieve more efficient and larger-scale 3D scanning. After obtaining the sample's 3D information from different viewpoints using the same calibration parameters, the sample's full-surface 3D data in the global coordinate can be obtained using mirror reflections. We conducted precision and effectiveness tests on samples with different sizes, materials, shapes, and textures to demonstrate the ability of the proposed method to perform full-surface 3D reconstruction under different scenarios. The experimental results of accuracy evaluation demonstrate that the proposed system can achieve a measurement accuracy at the level of 100 μm. Additionally, the robust experimental results in different scenarios also indicate that the proposed panoramic laser scanning system is capable of accurately obtaining full-surface 3D data of various types of samples, providing a cost-effective, easy-to-use, efficient, high-resolution, and effective approach for achieving panoramic 3D reconstruction.

“…Chai et al [18] employed the least squares circle and particle swarm algorithm to fit the center axis line for calculating the coaxiality error between splines and bevel gears. Cheng et al [19] proposed an improved robust Gaussian model for data segmentation and used orthogonal synthesis methods for reconstruction, achieving coaxiality measurements with an average error as low as 0.02 mm. However, there is still a lack of relevant measurement models in the field of rectangular spline shaft measurements.…”

Section: Introductionmentioning

confidence: 99%

Noncontact measurement of rectangular splines shaft based on line-structured light

Liu,

Li,

Wang

et al. 2024

The rectangular spline shaft, a typical type of shaft-tooth component, plays a significant role in mechanical transmissions. Existing methods for detecting size and positional tolerance in spline shafts often rely on contact-based measurement tech-niques, including specialized gauges and coordinate measuring machines (CMMs). To enhance the measurement efficiency, this paper proposes a method for measuring based on line-structured light. Firstly, a classification algorithm for data points on large and small cylindrical surfaces and keyway surface of spline shaft is established, contributing to the automatic measurement. Secondly, a coaxiality error measurement model is established based on the overall least squares method, improving the measurement accuracy. Finally, a measurement model for key width and positional tolerance is established through the rotation of the spline axis. In experiments, the size and positional tolerance of the spline shaft obtained using this method are compared with measurements by CMM, meeting the general machining accuracy requirements.