CN-122015704-A - System and method for detecting roundness error of shaft parts

CN122015704ACN 122015704 ACN122015704 ACN 122015704ACN-122015704-A

Abstract

The application belongs to the technical field of size detection and discloses a system and a method for detecting roundness errors of shaft parts, wherein the system comprises an air floatation supporting seat, a supporting seat and a supporting seat, wherein the air floatation supporting seat is used for supporting the lower end face of the shaft parts to be detected; the measuring system comprises a plurality of measuring units which are distributed at intervals along the up-down direction, wherein each measuring unit comprises an interferometer and a measuring head, the measuring heads are used for being in contact with the peripheral surface of the shaft to be measured so as to generate displacement along with the profile change of the shaft to be measured, the interferometer is used for converting the displacement of the measuring heads into interference fringe images and outputting the interference fringe images, and the upper computer is used for calculating roundness errors of the shaft to be measured at a plurality of different cross sections according to the interference fringe images so as to calculate the overall roundness errors of the shaft to be measured, so that a feasible technical scheme is provided for accurate and efficient detection of the large shaft to be measured.

Inventors

LI JINGCHONG
LI YANWEI
LI JIANJIE
LI JUNCHI
ZHANG SHIHENG
LIU HUAQIU
Guo Aodian

Assignees

季华实验室

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. A shaft roundness error detection system, comprising: the air floatation support seat (1) is used for supporting the lower end face of the shaft piece (90) to be tested; the rotation driving mechanism (2) is arranged above the air floatation supporting seat (1) and is used for driving the shaft piece (90) to be tested to rotate around the axis of the shaft piece (90) to be tested from the upper end of the shaft piece (90) to be tested; The positioning mechanism comprises a V-shaped positioning component (3) and a pre-tightening component (4) which are oppositely arranged, the V-shaped positioning component (3) is provided with a V-shaped positioning groove (301), and the pre-tightening component (4) is used for providing pre-tightening pressure for the shaft piece (90) to be tested so that the peripheral surface of the shaft piece (90) to be tested is attached to two positioning groove surfaces (302) of the V-shaped positioning groove (301); The measuring system comprises a plurality of measuring units (5) which are arranged at intervals along the up-down direction, wherein each measuring unit (5) comprises an interferometer (501) and a measuring head (502) which is arranged in linkage with a movable reflecting mirror (5015) of the interferometer (501), the measuring heads (502) are used for being in contact with the peripheral surface of the shaft piece (90) to be measured so as to generate displacement along with the contour change of the shaft piece (90) to be measured, and the interferometer (501) is used for converting the displacement of the measuring heads (502) into interference fringe images and outputting the interference fringe images; The upper computer (6) is used for calculating roundness errors of the shaft piece (90) to be measured at a plurality of different cross sections according to interference fringe images output by the measuring units (5), and calculating the overall roundness error of the shaft piece (90) to be measured by integrating the roundness errors of the cross sections.
2. The system for detecting roundness error of shaft parts according to claim 1, wherein the V-shaped positioning component (3) comprises a fixed seat (303), two swinging blocks (304) and two swinging driving devices (305), the two swinging blocks (304) are arranged on one side, close to the pre-tightening component (4), of the fixed seat (303) in a swinging mode, positioning groove surfaces (302) are arranged on one sides, close to each other, of the two swinging blocks (304), V-shaped positioning grooves (301) are formed between the two positioning groove surfaces (302), and the two swinging driving devices (305) are respectively used for driving the two swinging blocks (304) to swing so as to adjust included angles between the two positioning groove surfaces (302).
3. The system for detecting roundness error of shaft parts according to claim 1, wherein polytetrafluoroethylene coatings are arranged on two positioning groove surfaces (302) of the V-shaped positioning groove (301).
4. The shaft roundness error detection system according to claim 1, wherein the pre-tightening assembly (4) comprises a pressing piece (401), a pre-tightening spring (402), a pressing piece (403), a pressure sensor (404), an adjusting piece (405) and a fixing screw (406), the pressing piece (403) is slidably sleeved at one end of the fixing screw (406) close to the V-shaped positioning assembly (3), the adjusting piece (405) is arranged at one side of the pressing piece (403) away from the V-shaped positioning assembly (3) and is in threaded connection with the fixing screw (406), the pressure sensor (404) is arranged between the pressing piece (403) and the adjusting piece (405), the pressing piece (401) is arranged at one side of the pressing piece (403) close to the V-shaped positioning assembly (3), the pre-tightening spring (402) is connected between the pressing piece (403) and the pressing piece (401), and the pre-tightening spring (402) is used for providing elastic force to press the pressing piece (401) against the circumference surface of the shaft (90) to be measured.
5. The shaft roundness error detection system of claim 1, characterized in that the interferometer (501) comprises a light source (5011), an interference light path component comprising a beam splitter (5013), a fixed mirror (5014), and the movable mirror (5015), and an image sensor (5012).
6. The shaft roundness error detection system of claim 5, wherein said light source (5011) comprises two switchable lasers, two of which are a helium-neon laser and a semiconductor laser, respectively.
7. A method for detecting roundness errors of shaft parts is characterized in that, a shaft class piece roundness error detection system based on any of claims 1-6, comprising the steps of: A1. After a shaft piece (90) to be detected is arranged on a shaft piece roundness error detection system in a vertical posture, driving the shaft piece (90) to be detected to rotate for one circle, and collecting interference fringe images of a plurality of different cross sections of the shaft piece (90) to be detected in real time; A2. preprocessing the interference fringe image, wherein the preprocessing comprises graying processing, dynamic noise reduction processing and fringe sharpening processing; A3. Extracting pixel positions of zero-order fringes and secondary fringes in each preprocessed interference fringe image; A4. For each cross section, calculating zero-order fringe pixel displacement and secondary fringe pixel displacement corresponding to each two adjacent frames of interference fringe images according to pixel positions of the zero-order fringes and the secondary fringes, and verifying and correcting the zero-order fringe pixel displacement based on the secondary fringe pixel displacement; A5. for each cross section, calculating the actual displacement of the corresponding measuring head (502) according to the zero-order stripe pixel displacement after each verification and correction to obtain an actual displacement sequence of each cross section; A6. According to the actual displacement sequence, calculating roundness errors of each cross section by using a three-point method and a minimum area method in combination with an actual groove top angle of a V-shaped positioning groove (301) and a preset error transfer matrix corresponding to the actual groove top angle; A7. and calculating the overall roundness error of the shaft piece (90) to be measured by integrating the roundness errors of the cross sections.
8. The method for detecting roundness error of shaft elements according to claim 7, wherein step A3 includes: A301. based on an otsu threshold segmentation algorithm, determining a background area and a fringe area in the preprocessed interference fringe image, and setting the gray value of the background area to zero to obtain a zero-set interference fringe image; A302. Calculating the sum of gray values of pixels in each column of the interference fringe image after zero setting according to the extending column direction of the fringe area, and extracting column coordinates corresponding to the maximum value of the sum of the gray values as the pixel position of the zero-order fringe; A303. Searching local extreme points of the sum of the gray values along two sides by taking the pixel position of the zero-level stripe as the center, and determining the pixel position of the +/-1-level secondary stripe by combining with a preset stripe period; A304. the pixel positions of the zero-level stripes and the secondary stripes are corrected by kalman filtering.
9. The method for detecting roundness errors of shaft elements according to claim 8, wherein step A4 includes: A401. For each cross section, respectively calculating the difference of pixel positions of zero-order stripes, the difference of pixel positions of +1-order secondary stripes and the difference of pixel positions of-1-order secondary stripes corresponding to every two adjacent frames of interference stripe images to obtain corresponding zero-order stripe pixel displacement, +1-order secondary stripe pixel displacement and-1-order secondary stripe pixel displacement; A402. Calculating the absolute difference between the zero-order stripe pixel displacement and the corresponding +1-order secondary stripe pixel displacement, and marking the absolute difference as a first absolute difference, and calculating the absolute difference between the zero-order stripe pixel displacement and the corresponding-1-order secondary stripe pixel displacement, and marking the absolute difference as a second absolute difference; A403. and if the first absolute difference value and the second absolute difference value are not larger than a preset threshold value, judging that the zero-level stripe pixel displacement is effective, otherwise, judging that the zero-level stripe pixel displacement is ineffective and performing exception handling.
10. The method for detecting roundness errors of shaft parts according to claim 7, wherein steps A1 to A6 are repeated a plurality of times to obtain a plurality of said roundness errors for each cross section; Step A7 includes: A701. Calculating the average value of all the roundness errors of each cross section to obtain the effective roundness error of each cross section; A702. And carrying out weighted sum operation or weighted average sum operation on the effective roundness errors of each cross section according to the preset weight of each cross section to obtain the overall roundness error of the shaft piece (90) to be tested.

Description

System and method for detecting roundness error of shaft parts Technical Field The application relates to the technical field of size detection, in particular to a system and a method for detecting roundness errors of shaft parts. Background Currently, roundness error measurement of shaft parts mainly depends on a high-precision roundness measuring instrument. Although roundness measuring instruments can provide extremely high sampling accuracy and assessment accuracy, the roundness measuring instruments are mainly applicable to roundness error measurement of medium and small parts due to high cost and limitation of equipment specifications. This results in the limitations of existing roundness measuring instruments being particularly pronounced in the face of large, heavy shaft types, particularly those that require submicron roundness error accuracy. Specifically, for special shaft parts such as a large shaft diameter, a long shaft and the like, the influence of the systematic error of the roundness measuring instrument on the measurement precision is obviously increased, and the limited measurement space cannot accommodate such large-sized workpieces. Therefore, in actual production and detection, a large-scale shaft roundness error detection means which is universally applicable and can meet the high-precision requirement is lacking. In the prior art, the roundness error measurement problem of large-size and high-precision shaft parts is difficult to effectively solve, and particularly, under the requirement of submicron precision, how to accurately and efficiently detect special shaft parts such as large shaft diameters, long shafts and the like becomes a technical problem to be solved currently. In view of the above, there is a need in the art for improvements. Disclosure of Invention The application aims to provide a system and a method for detecting roundness errors of shaft parts, and aims to solve the problems that in the prior art, large-sized and heavy-duty shaft parts, particularly shaft parts which need submicron-level roundness error precision, lack a commonly applicable roundness error detection means which can meet high-precision requirements. In a first aspect, the present application provides a system for detecting roundness errors of shaft parts, including: The air floatation support seat is used for supporting the lower end face of the shaft piece to be tested; The rotation driving mechanism is arranged above the air floatation supporting seat and is used for driving the shaft piece to be tested to rotate around the axis of the rotation driving mechanism from the upper end of the shaft piece to be tested; the positioning mechanism comprises a V-shaped positioning component and a pre-tightening component which are oppositely arranged, the V-shaped positioning component is provided with a V-shaped positioning groove, and the pre-tightening component is used for providing pre-tightening pressure for the shaft piece to be tested so that the peripheral surface of the shaft piece to be tested is attached to two positioning groove surfaces of the V-shaped positioning groove; The measuring system comprises a plurality of measuring units which are arranged at intervals along the up-down direction, wherein each measuring unit comprises an interferometer and a measuring head which is arranged in linkage with a movable reflecting mirror of the interferometer, and the measuring head is used for being in contact with the peripheral surface of the shaft piece to be measured so as to generate displacement along with the profile change of the shaft piece to be measured; And the upper computer is used for calculating the roundness errors of the shaft piece to be measured at a plurality of different cross sections according to the interference fringe images output by the measuring units, and calculating the overall roundness error of the shaft piece to be measured by integrating the roundness errors of the cross sections. In a second aspect, the present application provides a method for detecting roundness error of shaft parts, based on the system for detecting roundness error of shaft parts, comprising the steps of: A1. after a shaft piece to be detected is arranged on a shaft piece roundness error detection system in a vertical posture, driving the shaft piece to be detected to rotate for one circle, and collecting interference fringe images of a plurality of different cross sections of the shaft piece to be detected in real time; A2. preprocessing the interference fringe image, wherein the preprocessing comprises graying processing, dynamic noise reduction processing and fringe sharpening processing; A3. Extracting pixel positions of zero-order fringes and secondary fringes in each preprocessed interference fringe image; A4. For each cross section, calculating zero-order fringe pixel displacement and secondary fringe pixel displacement corresponding to each two adjacent frames of interference fringe im