CN103615985A - Method for measuring diameter of steering knuckle based on three-dimensional scanning data - Google Patents
Method for measuring diameter of steering knuckle based on three-dimensional scanning data Download PDFInfo
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- CN103615985A CN103615985A CN201310680882.6A CN201310680882A CN103615985A CN 103615985 A CN103615985 A CN 103615985A CN 201310680882 A CN201310680882 A CN 201310680882A CN 103615985 A CN103615985 A CN 103615985A
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Abstract
The invention belongs to the field of industrial measurement and relates to a method for measuring the diameter of a large-sized workpiece (an automobile steering knuckle). The method solves the defects that the traditional measurement is low in precision due to direct contact with a workpiece and the workpiece is polluted easily, and has the advantages of high precision, high real-time property and capabilities of reducing the labor intensity of workers and improving the system reliability. The method comprises the following steps: generating scanned workpiece point cloud into data by using a three-dimensional scanner which is built on the basis of a binocular vision system principle, and inputting the data into three-dimensional processing software of a personal computer (PC); accurately splicing the scanned point cloud data together by using Geomagic Studio software to generate an integrated three-dimensional image, and performing data merging and encapsulation processing, so that the image reaches the optimal measuring state; selecting three points of the workpiece to determine a plane, and intercepting a cylindrical cross section by using a multiple cross section curve to generate a cross section curve graph; and determining two endpoints and measuring in real time to acquire the distance between the two points, namely the diameter of the cylindrical cross section round.
Description
Technical field
The present invention relates to two kinds of measuring workpieces (spindle) diameter method based on 3 d scan data, more particularly, the present invention relates to a kind of (spindle) diameter measuring method for large workpiece complete three dimensional image.
Background technology
Along with the appearance of the development of three-dimensional measurement technology, particularly spatial digitizer, in real world, the shape of object or environment (geometrical construction) has also obtained accurate measurement with appearance data (as character such as color, surface albedos).Steering knuckle diameter measuring method process flow diagram as shown in Figure 1.
Steering knuckle is one of critical part on steering axle of automobile, can make vehicle steadily travel and sensitive transmission travel direction, and the function of steering knuckle is to bear automotive front load, supports and drive front-wheel to make motor turning around stub rotation.Under motoring condition, it is bearing changeable shock load, therefore, requires it to have very high intensity.Steering knuckle is as shown in Fig. 2 (a).
So far, researchist is also doing a lot of research aspect measurement large-scale workpiece diameter dimension both at home and abroad.Domestic conventional large-scale workpiece On-line Measuring Method mainly contains by many groups parallel light workpiece imaging, utilizes the information of many group workpiece images to determine the methods such as bifocal path technique of the measuring workpieces diameter of people's propositions such as the diameter of workpiece for measurement and Feng Zhengming, Jiang Zhicheng, Li Jingjie.
External workpiece calibration system is mainly by advanced technologies such as computer science and artificial intelligence, to realize robotization and the intellectuality of measuring system at present.The Diameter Measurement System of the RDMS4200 series that reasonable large-scale workpiece Diameter Measurement System mainly contains U.S. Technical Sourcing Internation exploitation to small-caliber steel pipe, this system can be rotated around product, its per minute can provide the profile information of 140 steel pipes, and receive by CCD camera, its on-line velocity is less than in the situation of 500m/min, and complete diameter figure can be provided preferably.The advantage of the method is that the rotational speed of measuring system is very fast; resolution is higher; be better than 0.01mm; adopted the photoelectric encoder of the accurate measurement rotating mirror anglec of rotation; there is gas cleaning system and make system downtime the shortest, show different product sectional drawing, can measure different product cross sections; for example square, sexangle etc.
The RDMS laser diameter measuring instrument that also has in addition the development of German LAP company, it is specifically designed to the non-cpntact measurement of small-sized tubing.This product fundamental type is RDMS900 and RDMS180, and it can measure the outside dimension of line, rod and tubing that maximum gauge is respectively 80mm and 160mm, and measuring accuracy can reach 0.001mm.This system is measured by the mode of laser scanning.
German federal physical technique research institute (PTB) has dropped into a large amount of funds and strength in high precision diameter measurement field, and obtained technical merit advanced in the world, for the different demands from metering field and industrial sector, they have adopted respectively diverse ways to measure this crucial value.With regard to its technical merit, wherein outstanding with diameter and the cylindrical shape measuring comparator developed voluntarily.This diameter and the shape measure comparator of PTB development, the method that has adopted mechanical soft gauge head to be combined with laser interferometry, realizes the absolute measurement of cylinder internal-and external diameter high precision, and adopt, compares and realizes the shape measure of cylindrical workpiece with standard periphery.Contact gauge head is comprised of the measuring staff with dynamometry control gear and ruby spheric probe, the centre of sphere at two gauge heads of initial position of measuring is coaxial in horizontal and vertical directions, gauge head pulls open respectively and contacts and find maximum gauge position with two faces of measured piece subsequently, and the distance that gauge head moves is measured by laser interferometer.Instrument is strictly followed abbe ' s principle in structural design, farthest reduces the impact of second order error on measurement result, and by the dynamic property of the instrument of Design of Mechanical Structure raising cleverly.Mechanical framework on chain tape is made by invar material, and temperature expansion coefficient is very little, has effectively avoided temperature variation on the impact of measuring.The high-technology index that PTB proposes when development diameter and shape measure comparator is: outside diameter measuring scope 0～100mm, uncertainty of measurement reaches U=10nm/100mm, k=2, inner diameter measurement scope 10～100mm, uncertainty of measurement reaches U=15nm/100mm, k=2; The level reaching is at present that outside diameter measuring uncertainty is U=12nm/100mm, k=2, and inner diameter measurement uncertainty is U=30nm/100mm, k=2.
In addition, the method Switzerland Measurement Laboratory of Switzerland's Measurement Laboratory (0FMET) is transformed with coordinate measuring machine a Tianwan businessman for solving high precision shaft hole diameter measurement problem, they utilize CMM worktable and guide rail, mechanical gauge head are combined with laser interferometer realize to measure.Laser interferometer design to avoid producing Abbe error, is designed with dynamometry control gear on mechanical gauge head centre of sphere line on mechanical gauge head, realize dynamometry deformation-compensated.This apparatus measures scope is: [<700mm, uncertainty of measurement is U=62nm/40mm, k=2, uncertainty reaches 10-6 magnitude relatively.The feature of instrument is: gauge head is processed by the electrocorrosion of monoblock invar material, and thermal stability, rigidity and dynamic property are good, and such design has increased vertical direction degree of freedom, eliminates gauge head hysteresis phenomenon.In addition, gauge head adopts capacitive transducer to control dynamometry, realizes dynamometry and pushes back to zero, thereby eliminated the impact of dynamometry on measurement result in high-acruracy survey.Another characteristic part of this instrument is to adopt level crossing interferometer, to realize gauge head at the removable measured workpiece of crossing of Z direction, is convenient for measuring; But this light path design has improved the requirement to guide rail linearity simultaneously.But for guaranteeing that measured position is real diametrical position, must in two planes of horizontal and vertical, find extreme point, and measuring head diameter also needs to demarcate in advance while measuring.
Because contact type measurement need directly contact with workpiece, precision is lower, and easily workpiece is polluted, operation inconvenience; And described measuring method is based on principle of computer vision, synthetic by the scanning of spatial digitizer and the processing of 3-D view process software, on the stereoscopic three-dimensional image of spindle, measure and analyze.This method is carried out operational processes in the situation that not touching workpiece, and precision is high, and real-time has reduced workman's labour intensity, has improved the production efficiency of workpiece.
Summary of the invention
The invention provides a kind of steering knuckle diameter measuring method based on 3 d scan data: through spatial digitizer, scan and pass through three-dimensional software and process, obtain complete stereoscopic three-dimensional image.The steering knuckle diameter measurement carrying out on this basis can reach rapidly, accurate result.The present invention's spatial digitizer used is as shown in Fig. 2 (b).
The hardware system of described steering knuckle diameter measuring method comprises:
For steering knuckle being carried out to 1 of the optical photographing formula spatial digitizer of 3-D scanning processing;
For one, the computing machine of precision control, image acquisition and data processing;
The steering axle inner diameter measurement method based on 3 d scan data that the present invention is designed, concrete operation step is as follows:
Step 1: described optical photographing formula spatial digitizer is the large-scale workpiece scanning (spindle) some cloud generating three-dimensional data, and imported in the middle of the 3D processing software of PC; Then, utilize Geomagic Studio software accurately to stitch together the cloud data that scans all angles and generate complete three-dimensional image, and merge and encapsulation process, make image reach optimum measurement state.
Spliced and process after spindle 3-D view as shown in Figure 3;
Step 2: to flush.
In the circle of a unknown center of circle radius, be difficult to determine which bar line segment is only diameter of a circle.Therefore rely on naked eyes directly at cylindrical objects, to select 2 line segments that are linked to be not accurate enough as diameter of a circle.At tested cylindrical objects, to survey and in circular plane, choose 3 points, thereby establish a plane, make it the axle perpendicular to x, and the plane parallel forming with y axle and z axle.As shown in Fig. 4 (a);
Step 3: by multiple cross section curve intercepting cylindrical cross section.
In described step 2, established yz plane, cylindrical cross section is also parallel to yz plane, utilize Geomagic Studio software to set up multiple cross section curve and intercept cylindrical cross section, the curved surface of intercepting is more in theory, and the diameter data of the shorter measurement of distance between curved surface is more accurate.Design sketch after intercepting is as shown in Fig. 4 (b);
Step 4: generate cross section curve figure and measure.
In described step 3, intercept cylindricality plane, needed to generate cross section curve figure.Through calculating, cross section curve figure is as shown in Fig. 4 (c);
Turning of work piece angle in the cross section curve figure generating, makes it to match with outboard profile.Wherein, need to carefully rotate, carefully screen, thereby determine the diameter two-end-point that will survey cylindricality.Specifically measure as shown in Fig. 4 (d);
Tested cylindricality is amplified to a certain degree (if choose 2 points on smaller figure, error can be larger), choose two end points that are similar to a line segment, and utilize distance measurement function in Geomagic Studio software to record the distance of two-end-point, be cylindrical cross-section diameter of a circle.
The invention has the beneficial effects as follows: in the situation that not touching workpiece, carry out operational processes, precision is high, real-time, has reduced workman's labour intensity, has improved the production efficiency of workpiece.
Accompanying drawing explanation
Fig. 1: steering knuckle diameter measuring method process flow diagram;
Fig. 2 (a): spindle;
Fig. 2 (b): optical 3-dimensional photo taking type scanner;
Fig. 3: the complete three dimensional image after processing;
Fig. 4 (a): choose 3 points, establish plane;
Fig. 4 (b): multiple camber intercepting cylindrical cross section;
Fig. 4 (c): cross section curve figure;
Fig. 4 (d): tested cylindrical cross-section curve magnification figure.
Embodiment
The present invention proposes a kind of steering knuckle diameter measuring method based on 3 d scan data: set up multiple cross section curve and measure steering axle diameter, described method is all the complete three-dimensional data gained of workpiece that collect based on optical photographing formula spatial digitizer.Steering knuckle diameter measuring method process flow diagram as shown in Figure 1.
Steering knuckle is one of critical part on steering axle of automobile, can make vehicle steadily travel and sensitive transmission travel direction, and the function of steering knuckle is to bear automotive front load, supports and drive front-wheel to make motor turning around stub rotation.Under motoring condition, it is bearing changeable shock load, therefore, requires it to have very high intensity.Steering knuckle is as shown in Fig. 2 (a).
The purposes of spatial digitizer is the some cloud (point cloud) that creates object geometric jacquard patterning unit surface, and these points can be used to the surface configuration that interpolation becomes object, and more intensive some cloud can create more accurate model, and this process is called three-dimensional reconstruction.If scanner can be obtained surface color, can further on the surface rebuilding, paste texturing, that is so-called material seal is penetrated.
Measure herein steering knuckle used be optical photographing formula scanner, it is a kind of three-dimensional scanning measurement equipment of high-speed, high precision, employing be state-of-the-art structured light noncontact photographic measurement principle in the world at present.This scanner can be measured a face simultaneously, the structured light that during measurement, grating projection device is counted width specific coding is to object under test, two cameras that form an angle are synchronously adopted to obtain respective image, then image is decoded and phase calculation, and utilize matching technique, triangulation principle, calculate the three-dimensional coordinate of pixel in two public vision areas of video camera.The present invention's spatial digitizer used is as shown in Fig. 2 (b).
The steering knuckle diameter measuring method based on 3 d scan data that the present invention is designed, concrete operation step is as follows:
Step 1: described optical photographing formula spatial digitizer is by the large-scale workpiece scanning (spindle) some cloud generated data, and imported in the middle of the 3D processing software of PC, then, utilize Geomagic Studio software accurately to stitch together the cloud data that scans all angles and generate complete three-dimensional image, and merge and encapsulation process, make image reach optimum measurement state.
Geomagic is a real-time three-dimensional scanning, three-dimensional point cloud and triangle gridding editting function and comprehensively CAD shape-designing, assembling modeling, the two dimension Three-dimensional Design Software of function such as publish picture that combines of industry.Spliced and process after spindle 3-D view as shown in Figure 3.By as mentioned above, just obtain the complete three dimensional image of workpiece (spindle).
In the circle of a unknown center of circle radius, be difficult to determine which bar line segment is only diameter of a circle.Therefore rely on naked eyes directly at cylindrical objects, to select 2 line segments that are linked to be not accurate enough as diameter of a circle.Given this, invent a kind of method that multiple cross section curve is measured steering axle diameter of setting up.
Step 2: to flush.
At tested cylindrical objects, to survey and in circular plane, choose 3 points, thereby establish a plane, make it the axle perpendicular to x, and the plane parallel forming with y axle and z axle;
Step 3: by multiple cross section curve intercepting cylindrical cross section.
In described step 2, established yz plane, cylindrical cross section is also parallel to yz plane, utilize Geomagic Studio software to set up multiple cross section curve and intercept cylindrical cross section, the curved surface of intercepting is more in theory, and the diameter data of the shorter measurement of distance between curved surface is more accurate;
Step 4: generate cross section curve figure and measure.
In described step 3, intercept cylindricality plane, needed to generate cross section curve figure.Turning of work piece angle in the cross section curve figure generating, makes it to match with outboard profile.Wherein, need to carefully rotate, carefully screen, thereby determine the diameter two-end-point that will survey cylindricality.Tested cylindricality is amplified to a certain degree (if choose 2 points on smaller figure, error can be larger), choose two end points that are similar to a line segment, and utilize distance measurement function in Geomagic Studio software to record the distance of two-end-point, be cylindrical cross-section diameter of a circle.
In sum, two kinds of advantages of measuring large-scale workpiece (spindle) diameter method of the present invention are:
1) do not contact with measurand, weakened to the full extent the impact between observer and the person of being observed, improve the reliability of system.
2) precision is high, and real-time has reduced workman's labour intensity, has improved the production efficiency of workpiece.
Below schematically the present invention and embodiment thereof are described, this description does not have limitation, and shown in accompanying drawing is also one of embodiments of the present invention.So; if those of ordinary skill in the art is enlightened by it; in the situation that not departing from the invention aim; adopt the same base part of other form or each component layouts mode of other form; without the creationary technical scheme similar to this technical scheme and the embodiment of designing, all should belong to protection scope of the present invention.
Claims (1)
1. the steering knuckle diameter measuring method based on 3 d scan data: set up multiple cross section curve and measure steering axle diameter; Described 3 d scan data is that scanning the processing of the optical photographing formula spatial digitizer through building based on binocular vision system principle obtains, described optical photographing formula spatial digitizer is a kind of three-dimensional scanning measurement equipment of high-speed, high precision, employing be state-of-the-art structured light noncontact photographic measurement principle in the world at present; Method comprises the steps:
Step 1: scan and carry out 3D processing;
Described optical photographing formula spatial digitizer is by the large-scale workpiece scanning (spindle) some cloud generated data, and imported in the middle of the 3D processing software of PC, then, utilize Geomagic Studio software accurately to stitch together the cloud data that scans all angles and generate complete three-dimensional image, and merge and encapsulation process, make image reach optimum measurement state;
Step 2: to flush;
In the circle of a unknown center of circle radius, be difficult to determine which bar line segment is only diameter of a circle; Therefore rely on naked eyes directly at cylindrical objects, to select 2 line segments that are linked to be not accurate enough as diameter of a circle; At tested cylindrical objects, to survey and in circular plane, choose 3 points, thereby establish a plane, make it the axle perpendicular to x, and the plane parallel forming with y axle and z axle;
Step 3: by multiple cross section curve intercepting cylindrical cross section;
In described step 2, established yz plane, cylindrical cross section is also parallel to yz plane, utilize Geomagic Studio software to set up multiple cross section curve and intercept cylindrical cross section, the curved surface of intercepting is more in theory, and the diameter data of the shorter measurement of distance between curved surface is more accurate;
Step 4: generate cross section curve figure and measure;
In described step 3, intercept cylindricality plane, needed to generate cross section curve figure; Turning of work piece angle in the cross section curve figure generating, makes it to match with outboard profile; Wherein, need to carefully rotate, carefully screen, thereby determine the diameter two-end-point that will survey cylindricality; Tested cylindricality is amplified to a certain degree (if choose 2 points on smaller figure, error can be larger), choose two end points that are similar to a line segment, and utilize distance measurement function in Geomagic Studio software to record the distance of two-end-point, be cylindrical cross-section diameter of a circle.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106441205A (en) * | 2016-11-30 | 2017-02-22 | 安徽江淮汽车集团股份有限公司 | Perpendicularity testing tool of steering knuckle |
| CN111256605A (en) * | 2020-02-11 | 2020-06-09 | 周海兵 | Automatic detection device and method for U-shaped copper pipe of air conditioner |
| CN112017293A (en) * | 2020-07-10 | 2020-12-01 | 北京工业大学 | Method for measuring geometric initial defects of round steel pipe |
| CN113485330A (en) * | 2021-07-01 | 2021-10-08 | 苏州罗伯特木牛流马物流技术有限公司 | Robot logistics carrying system and method based on Bluetooth base station positioning and scheduling |
| CN115451847A (en) * | 2022-09-09 | 2022-12-09 | 北京科技大学 | Bar stock measuring device, bar stock measuring method and storage medium |
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2013
- 2013-12-09 CN CN201310680882.6A patent/CN103615985A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106441205A (en) * | 2016-11-30 | 2017-02-22 | 安徽江淮汽车集团股份有限公司 | Perpendicularity testing tool of steering knuckle |
| CN106441205B (en) * | 2016-11-30 | 2018-10-09 | 安徽江淮汽车集团股份有限公司 | Knuckle detection tool for detecting verticality |
| CN111256605A (en) * | 2020-02-11 | 2020-06-09 | 周海兵 | Automatic detection device and method for U-shaped copper pipe of air conditioner |
| CN112017293A (en) * | 2020-07-10 | 2020-12-01 | 北京工业大学 | Method for measuring geometric initial defects of round steel pipe |
| CN112017293B (en) * | 2020-07-10 | 2024-06-07 | 北京工业大学 | Method for measuring geometric initial defects of round steel pipe |
| CN113485330A (en) * | 2021-07-01 | 2021-10-08 | 苏州罗伯特木牛流马物流技术有限公司 | Robot logistics carrying system and method based on Bluetooth base station positioning and scheduling |
| CN115451847A (en) * | 2022-09-09 | 2022-12-09 | 北京科技大学 | Bar stock measuring device, bar stock measuring method and storage medium |
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