CN108917688B - Hole edge distance measuring method for eliminating roll-shaped beam plane distortion influence based on straight line fitting - Google Patents
Hole edge distance measuring method for eliminating roll-shaped beam plane distortion influence based on straight line fitting Download PDFInfo
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- CN108917688B CN108917688B CN201810843954.7A CN201810843954A CN108917688B CN 108917688 B CN108917688 B CN 108917688B CN 201810843954 A CN201810843954 A CN 201810843954A CN 108917688 B CN108917688 B CN 108917688B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/20—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring contours or curvatures, e.g. determining profile
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/16—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring distance of clearance between spaced objects
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Abstract
The invention provides a hole edge distance measuring method for eliminating the plane distortion influence of a roller-shaped beam based on straight line fitting, which utilizes the non-contact laser imaging principle, adopts four two-dimensional laser distance sensors to collect the profile data of the cross section of the roller-shaped beam, carries out coordinate transformation, rotation and translation on the image data collected by each sensor, carries out graph splicing to obtain the profile of the cross section of the roller-shaped beam, uses the least square method to fit straight lines, simplifies the profile of the cross section into n-shaped three straight lines which are intersected in pairs, records two intersection points of the three straight lines, re-measures once at a certain distance, records the intersection points, and finally calculates the distance between the straight lines and the hole center by using the continuous intersection points near the measured hole to represent the hole edge distance. The method can eliminate the influence of the plane distortion of the roller-shaped beam on the detection precision of the hole edge distance, and has high detection precision; the stability of continuous measurement is good, and the anti-interference capability is strong; the calculation principle is closer to the actual requirement.
Description
Technical Field
The invention belongs to the technical field of detection of commercial vehicle roller-shaped beams, and particularly relates to a hole edge distance measuring method for eliminating the influence of plane distortion of a roller-shaped beam based on linear fitting.
Background
With the rapid development of the automobile industry and the continuous improvement of the production automation level, whether the detection means is advanced or not becomes important for improving the production level. The roller-shaped beam of the commercial vehicle is one of key assemblies of the whole vehicle, is a reference for assembling the assemblies of an engine, a cab, an axle, front and rear plate springs, an oil tank, a battery box and the like, and is a bearing body for bending stress in the vertical direction and torsional stress generated in emergency braking, and is commonly called as a steel ridge beam. Therefore, the assembly of the frame more or less determines the performance of the whole vehicle, and the hole position precision of the three-sided punching part of the frame determines whether the subsequent process can be smoothly carried out. The quality detection in the current production process adopts full-automatic detection, can realize full detection, but in practical use, finds that the mass production type roller-shaped beam has certain torsion resistance, has great influence on a detection result, leads the measurement result of the hole edge distance to be incapable of being stabilized within +/-0.4 and loses the specified precision of the detection equipment, and the algorithm is a calculation method for eliminating the influence of the plane torsion of the roller-shaped beam on the hole edge distance detection precision based on line fitting, can eliminate the influence of the torsion resistance of the mass production type roller-shaped beam on the hole edge distance measurement on the beam, and ensures that defective products cannot flow to subsequent processes. Therefore, the method for measuring and calculating the edge distance of the roller-shaped beam hole based on straight line fitting has great practical significance.
Disclosure of Invention
Aiming at the problems in the prior art, the technical scheme adopted by the invention for solving the problems in the prior art is as follows:
a hole edge distance measuring method for eliminating the plane distortion influence of a roller-shaped beam based on straight line fitting is characterized by comprising the following steps:
step 1, calibrating data of a standard workpiece with a given size to obtain two sets of calibration parameters: rotation angles R1, R2, R3, R4 and offsets S1, S2, S3, S4;
step 2, acquiring partial data of the spatial position of a point on the cross section of the external profile of the roll-type beam by using four sensors positioned at the upper ends of a left airfoil surface, a right airfoil surface and a ventral surface of a three-sided punching precision detection device body of the roll-type beam, namely acquiring two-dimensional coordinates transmitted by the four sensors, and representing the spatial relative position of a measuring point by taking the spatial position of the sensors as an origin;
step 3, rotating the two-dimensional coordinate system obtained by the four sensors clockwise by R1, R2, R3 and R4, respectively translating the two-dimensional coordinate system to S1, S2, S3 and S4, and completing image splicing to obtain a section profile after the two-dimensional coordinate system is translated to the same coordinate origin;
and 4, dividing the section profile obtained by calculation in the step 3 into three parts of the left wing and the right wing, fitting a straight line by using a least square method according to a stable data point acquired by each part, finally simplifying the three straight lines into n-shaped two-by-two intersection, recording two intersection points of the three straight lines, measuring once again at a certain distance, recording the intersection points, and finally calculating the distance between the straight line and the hole center by using continuous intersection points near the measured hole to represent the hole edge distance.
The specific process of data calibration in the step 1 is as follows:
i, placing a standard workpiece with a given size on a detection station, and starting four sensors;
II, performing rotation transformation on data coordinate systems output by the four sensors, unifying the data coordinate systems into the same world coordinate system, and obtaining a first group of calibration parameters which are rotation angles R1, R2, R3 and R4;
and III, performing coordinate translation on the rotated data according to the size of the standard block to obtain a second set of calibration parameters which are data offset quantities S1, S2, S3 and S4.
And 4, when the first detection data is calculated in the step 4, selecting points from 350 th to 700 th of the sensor as stable data, wherein the data selection is related to parameter indexes of the beam, the noise of the points before 350 and after 700 is large and needs to be eliminated, obtaining a roller-shaped beam section profile simplified graph which is firstly collected and consists of three straight lines by using a least square method, collecting data points at intervals of 0.05-0.1mm, only keeping the data points which are less than 0.1mm away from the previous roller-shaped beam section profile simplified graph, calculating a new roller-shaped beam section profile simplified graph by using the least square method, and updating and iterating until the detection is finished.
The four sensors are four same Gocator2340 type line scanning sensors, the four sensors simultaneously acquire data and complete acquisition of profile data of the roller type beam section, the sensors do not have offset of measurement data caused by contrast difference caused by light intensity during scanning, and image data acquired by the sensors are subjected to coordinate transformation, rotation and translation to perform image splicing so as to acquire the profile of the roller type beam section.
The three-side punching precision detection device comprises four sensors, a servo motor, a linear guide rail, a roller-shaped beam limiting mechanism and a roller-shaped beam, wherein the four sensors are respectively a first sensor, a second sensor, a third sensor and a fourth sensor, linear laser ranging sensors with the same model are adopted, the four sensors are respectively arranged at the upper ends of a left wing surface, a right wing surface and a ventral surface of a main body of the three-side punching precision detection device, 2 sensors are arranged at the upper ends of the ventral surfaces side by side, the servo motor is arranged at the front end of the three-side punching precision detection device, the linear guide rail is arranged on a base and used for moving the four sensors, the limiting mechanism is fixed on the base and used for supporting and limiting the roller-shaped beam, when a workpiece is in place, the servo mechanism moves the sensors from the head end of the workpiece to the tail end of the workpiece at a constant speed, the servo mechanism then resets the sensor and the detection device repeats the process for each workpiece to achieve the scanning objective.
The invention has the following advantages:
1. the influence of the plane distortion of the roller-type beam on the detection precision of the hole edge distance can be eliminated, the precision is increased to the range of +/-0.2mm of a standard value, and the precision is improved by 5 to 11 times compared with the original precision;
2. the stability of continuous measurement is good, and the anti-interference capability is strong;
3. the calculation principle is closer to the actual requirement.
Drawings
FIG. 1 is a schematic structural diagram of a three-side punching precision detection device for a roller-shaped beam adopted by the invention;
FIG. 2 is a schematic view of four sensor mounting locations;
FIG. 3 is a schematic drawing showing the dimensions of the roll beam workpiece of FIG. 1: b is the ventral width, C is the airfoil height, and t is the material thickness;
FIG. 4 is a schematic diagram of a profile of a roller-shaped beam formed by splicing data acquired by four sensors;
FIG. 5 is a simplified cross-sectional profile of a roller-type beam;
FIG. 6 is a schematic diagram showing the distance between the straight line calculated by the least square method and the center of the hole near the continuous intersection point of the measured hole and the edge of the hole;
in the figure: 1-a first sensor, 2-a second sensor, 3-a third sensor, 4-a fourth sensor, 5-a servo motor, 6-a linear guide rail, 7-a limiting mechanism and 8-a roller beam.
Detailed Description
The technical scheme of the invention is further described in detail by the following embodiments and the accompanying drawings:
the invention provides a calculation method capable of solving the problem that plane distortion of a roller-shaped beam affects the detection precision of hole edge distance, which is realized by using a device shown in figure 1, wherein the device is disclosed in an authorized patent 'a roller-shaped beam three-side punching precision detection device' (application number is 201720663642). based on the device, a laser intelligent sensor scanning imaging technology is utilized to transmit an acquired image to a computer, and then the algorithm provided by the invention is used for calculating the precision of the hole edge distance of the roller-shaped beam.
The utility model provides a trilateral precision detection device that punches a hole of roller type roof beam includes four sensors, servo motor 5, linear guide 6, roller type roof beam stop gear 7 and roller type roof beam 8, four sensors are first sensor 1 respectively, second sensor 2, third sensor 3 and fourth sensor 4, all adopt the linear laser range finding sensor of the same model (such as Gocator2340 series), four sensors are installed respectively at the left airfoil of trilateral precision detection device main part that punches a hole, right flank face and ventral upper end, the ventral needs the scanning field of vision great, it is numerous to punch a hole, consequently, install 2 sensors side by side at the ventral upper end, servo motor 5 installs the front end at trilateral precision detection device that punches a hole, linear guide 6 installs on the base, be fixed with stop gear 7 on the base simultaneously, it is spacing with roller type roof beam 8 to be used for supporting. The installation positions of the four sensors are shown in fig. 2, the acquired section profile data points are respectively in respective sensor coordinate systems, and therefore data calibration is required before the device is used for detecting the roll-shaped beam hole edge distance, so that the device can output the complete roll-shaped beam profile.
The invention must carry on the data calibration before carrying on the detection of the beam hole edge distance of the roller type, the data calibration includes the following steps:
1. placing a standard workpiece with a given size on a detection station, and starting four sensors;
2. carrying out rotation transformation on data coordinate systems output by the four sensors, unifying the data coordinate systems into the same world coordinate system, and obtaining a calibration parameter A which is rotation angles R1, R2, R3 and R4;
3. and performing coordinate translation on the rotated data according to the size of the standard block to obtain a calibration parameter B, which is data offset S1, S2, S3 and S4.
The standard workpieces are firstly used for calibration, the rotation angles R1, R2, R3 and R4 and the translation amounts S1, S2, S3 and S4 are calculated, calibration is not needed to be carried out in each measurement, and the detection efficiency is improved.
As shown in fig. 3, which is a schematic diagram of the profile of the cross section of the roller-shaped beam, the roller-shaped beam to be detected is placed in a measurable area of a sensor, and the collected profile data of the roller-shaped beam is subjected to rotation and translation transformation by using a calibrated rotation angle and a calibrated translation amount to obtain a complete profile of the periphery of the cross section of the steel rail.
As shown in fig. 4, the sensor obtains the distance position relationship of points in the space, selects stable measurement points in the sensor (the points 350 to 700 of the sensor selected for the first time are stable data, the selection of stable data points is related to the parameter index of the beam, and the noise of the points before 350 and after 700 is large, so the stable data points are discarded), calculates the first acquired roller-type beam cross section outline simplified diagram formed by three straight lines by using the least square method, as shown in fig. 5, only data points with the distance less than 0.1mm from the last roller-type beam cross section outline simplified diagram are reserved in the data acquisition points at intervals, calculates a new roller-type beam cross section outline simplified diagram by using the least square method, and updates and iterates until the detection is finished.
Two intersections (intersections of three dotted lines in fig. 5) at which the straight lines of the simplified contour of each section intersect are recorded. And finally, calculating the distance between the outer edge line and the circle center of the hole by using continuous intersection points (intersection points provided by cross sections near a plurality of measured holes) near the measured hole through a least square method to represent the hole edge distance, wherein as shown in FIG. 6, the outer edge line is not corrected by the conventional algorithm, only one straight line is used for replacing the outer edge line, and the tail is calculated from the head. Specific comparative experimental data are shown in table 1.
The comparative test conditions were as follows:
1. the same roll-type beam; 2. the same detection equipment is adopted; 3. the prior art algorithm and the algorithm of the invention are respectively adopted as different hole edge distance measuring methods, and the obtained front and back comparison calculation data and the measured data are as follows:
TABLE 1 comparison of the measurement results of the same hole edge distance of the roller-shaped beam (unit: mm)
Comparative analysis of experimental data:
the experiment randomly selects three different types of roll-type beams on a production line, compares data with a new algorithm, randomly selects a key hole position on each beam, manually measures the key hole position by using a vernier caliper (0.02mm), measures the key hole position for 5 times by using the original algorithm and the new algorithm respectively, calculates an average value, compares a difference value, and finds that the precision of the new algorithm is improved by 5-11 times compared with that of the original algorithm.
The protective scope of the present invention is not limited to the above-described embodiments, and it is apparent that various modifications and variations can be made to the present invention by those skilled in the art without departing from the scope and spirit of the present invention. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims (3)
1. A hole edge distance measuring method for eliminating the plane distortion influence of a roller-shaped beam based on straight line fitting is characterized by comprising the following steps:
step 1, calibrating data of a standard workpiece with a given size to obtain two sets of calibration parameters: rotation angles R1, R2, R3, R4 and offsets S1, S2, S3, S4;
step 2, acquiring partial data of spatial positions of points on the cross section of the outer contour of the roll-type beam by using four sensors positioned at the upper ends of a left airfoil surface, a right airfoil surface and a ventral surface of a three-surface punching precision detection device body of the roll-type beam;
step 3, rotating the two-dimensional coordinate system obtained by the four sensors clockwise by R1, R2, R3 and R4, respectively translating the two-dimensional coordinate system to S1, S2, S3 and S4, and completing image splicing to obtain a section profile after the two-dimensional coordinate system is translated to the same coordinate origin;
step 4, dividing the section profile obtained in the step 3 into three parts of a left wing and a right wing, fitting a straight line by using a least square method, finally simplifying the three straight lines which are intersected in pairs in an n shape, recording two intersected points of the three straight lines, measuring again at regular intervals, recording the intersected points, and finally calculating the distance between the straight line and the circle center of the hole by using continuous intersected points near the measured hole to represent the hole edge distance;
the specific process of data calibration in the step 1 is as follows:
i, placing a standard workpiece with a given size on a detection station, and starting four sensors;
II, performing rotation transformation on data coordinate systems output by the four sensors, unifying the data coordinate systems into the same world coordinate system, and obtaining a first group of calibration parameters which are rotation angles R1, R2, R3 and R4;
III, performing coordinate translation on the rotated data according to the size of the standard block to obtain a second group of calibration parameters which are data offset S1, S2, S3 and S4;
and 4, when the first detection data is calculated in the step 4, selecting points from 350 th to 700 th of the sensor as stable data, obtaining a first acquired roller-shaped beam section profile simplified graph formed by three straight lines by using a least square method, acquiring data points at intervals of 0.05-0.1mm, only keeping the data points with the distance less than 0.1mm from the last acquired roller-shaped beam section profile simplified graph, calculating a new roller-shaped beam section profile simplified graph by using the least square method, and updating and iterating until the detection is finished.
2. The method for measuring the hole edge distance for eliminating the influence of the plane distortion of the roller-shaped beam based on the straight line fitting as claimed in claim 1, wherein: the four sensors are four identical Gocator2340 type line scanning sensors, and the four sensors simultaneously acquire data to finish acquisition of the profile data of the cross section of the roller type beam.
3. The method for measuring the hole edge distance for eliminating the influence of the plane distortion of the roller-shaped beam based on the straight line fitting as claimed in claim 1, wherein: the three-sided punching precision detection device comprises four sensors, a servo motor, a linear guide rail, a roller-shaped beam limiting mechanism and a roller-shaped beam, wherein the four sensors are respectively a first sensor, a second sensor, a third sensor and a fourth sensor, linear laser ranging sensors of the same model are adopted, the four sensors are respectively installed on the left wing surface, the right wing surface and the upper end of the ventral surface of a main body of the three-sided punching precision detection device, 2 sensors are installed on the upper end of the ventral surface side by side, the servo motor is installed at the front end of the three-sided punching precision detection device, the linear guide rail is installed on a base and used for moving the four sensors, and meanwhile, the base is fixedly provided with the limiting mechanism and is used for supporting and.
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| JP2833515B2 (en) * | 1995-03-23 | 1998-12-09 | ニチデン機械株式会社 | Method and apparatus for detecting direction of lead frame |
| CN101387493B (en) * | 2008-07-10 | 2010-09-08 | 长春理工大学 | Shape and position dimension non-contact photoelectric detection method for pylon component hole |
| CN101603818B (en) * | 2009-07-14 | 2011-02-02 | 中国科学院安徽光学精密机械研究所 | System and method for measuring width between perforated lines and width between perforated line and edge for tipping paper of cigarette |
| CN103895877B (en) * | 2014-03-27 | 2016-08-24 | 浙江大学 | Position, a kind of hole based on skeleton scanning survey modification method |
| CN106840033B (en) * | 2017-03-13 | 2019-11-26 | 武汉理工大学 | A kind of profile of steel rail detection device and method based on image procossing |
| CN207215017U (en) * | 2017-06-07 | 2018-04-10 | 武汉桑普瑞奇科技有限公司 | A kind of roll shape beam three-face punching accuracy detecting device |
| CN107632022A (en) * | 2017-08-30 | 2018-01-26 | 武汉理工大学 | A kind of detection method of surface flaw of steel rail and device based on data processing |
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Effective date of registration: 20211104 Address after: 441300 No. 38-108 Wendi Avenue, Suizhou City, Hubei Province Patentee after: Industrial Research Institute of Wuhan University of technology in Suizhou Address before: 430070 Hubei Province, Wuhan city Hongshan District Luoshi Road No. 122 Patentee before: WUHAN University OF TECHNOLOGY |