CN110285756A - Photo-electric automobile chassis measuring instrument - Google Patents
Photo-electric automobile chassis measuring instrument Download PDFInfo
- Publication number
- CN110285756A CN110285756A CN201910637416.7A CN201910637416A CN110285756A CN 110285756 A CN110285756 A CN 110285756A CN 201910637416 A CN201910637416 A CN 201910637416A CN 110285756 A CN110285756 A CN 110285756A
- Authority
- CN
- China
- Prior art keywords
- point
- measuring
- light source
- point light
- adapter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001514 detection method Methods 0.000 claims abstract description 16
- 238000006243 chemical reaction Methods 0.000 claims abstract description 8
- 238000005259 measurement Methods 0.000 claims description 39
- 238000000034 method Methods 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 8
- 238000009434 installation Methods 0.000 claims description 5
- 210000003813 thumb Anatomy 0.000 claims description 3
- 239000011159 matrix material Substances 0.000 description 15
- 230000009466 transformation Effects 0.000 description 7
- 238000013519 translation Methods 0.000 description 6
- 238000013461 design Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000012423 maintenance Methods 0.000 description 5
- 239000000523 sample Substances 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 238000013507 mapping Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000008439 repair process Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/002—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates
- G01B11/005—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates coordinate measuring machines
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
- G01B5/0025—Measuring of vehicle parts
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The present invention provides a kind of high-precision, easily and efficiently photo-electric automobile chassis measuring instrument, belongs to automobile chassis detection field.The present invention includes processor, video camera and surveys stick, and surveying stick includes ontology, several point light sources and gauge head；Gauge head is fixed on ontology top, and gauge head is directly or indirectly contacted with the tested point on automobile chassis, and several point light sources are distributed on the side of ontology；Video camera, opposite with the point light source surveyed on stick, the point source image of stick is surveyed in acquisition；Processor, receive the image that video camera obtains, using luminous point light source as feature, the characteristic point in described image is extracted, according to the actual positional relationship surveyed on stick between point light source and point light source, characteristic point is matched with point light source on stick is surveyed, in conjunction with the actual positional relationship between point light source and gauge head, position coordinates of the gauge head under camera coordinates system are determined, which is converted into the position coordinates under the coordinate system of chassis, tested point position is determined according to the position coordinates after conversion, completes detection.
Description
Technical Field
The invention relates to an automobile chassis measuring instrument, and belongs to the field of automobile chassis detection.
Background
With the rapid development of automobile industry in recent years, vehicles have become the category of normal expenses of each family, the quantity of automobile maintenance in China is rapidly increased, automobile damage and collision accidents happen occasionally, and a large amount of automobile maintenance services are followed, so that the requirement of automobile maintenance is rapidly increased. In the aspect of automobile maintenance, common fault diagnosis analysis and maintenance service of an automobile chassis also shows an increasing trend. How to ensure that the chassis reaches the technical performance index when leaving the factory after being maintained after the vehicle is collided becomes an important problem in the automobile industry.
In the early stage of automobile repair, workshop workers often distinguish whether the automobile chassis is deformed or not and how much the deformation quantity is, so that the uncertainty of vehicle repair is very large. With the rapid development of industrialization, people gradually apply the three-dimensional measurement technology to the field of automobile chassis detection. However, the currently used three-dimensional detection systems such as three-coordinate measuring machines and articulated arms of robots generally have the disadvantages of limited detection range, high cost, poor measurement flexibility and the like. Systems such as laser interferometers and electronic theodolites are complex to operate, low in measurement efficiency and expensive.
Disclosure of Invention
Aiming at the defects, the invention provides the photoelectric automobile chassis measuring instrument which is high in precision, convenient and quick.
The invention relates to a photoelectric automobile chassis measuring instrument, which comprises a processor 3, a camera 2 and a measuring rod 1;
the measuring rod 1 comprises a body, a plurality of point light sources and a measuring head;
the measuring head is fixed at the top end of the body and is used for directly or indirectly contacting with a point to be measured on the automobile chassis, and the plurality of point light sources are distributed on one side surface of the body;
the camera 2 is opposite to the point light source on the measuring stick 1 and is used for collecting the point light source which emits light on the body of the measuring stick 1 and acquiring an image;
and the processor 3 is connected with the camera 2 and used for receiving the image acquired by the camera 2, taking the light-emitting point light source as a feature, extracting a feature point in the image, matching the feature point in the image with the point light source on the measuring bar 1 according to the actual position relationship between the point light source on the measuring bar 1 and the point light source, determining the position coordinate of the measuring head under a camera coordinate system by combining the actual position relationship between the point light source and the measuring head after matching is finished, converting the position coordinate of the measuring head under the camera coordinate system into the position coordinate under a chassis coordinate system by combining the conversion relationship between the camera coordinate system and the chassis coordinate system, and determining the position of a point to be measured on the automobile chassis according to the position coordinate of the measuring head under the chassis coordinate system to finish detection.
Preferably, the plurality of point light sources are not coplanar.
Preferably, the measuring rod 1 further comprises a handle and a trigger button, the handle is fixed to the other side face of the body and used for being held by an operator to detect the automobile chassis, the trigger button is installed on the handle, the installation position of the trigger button is opposite to the position of the thumb of the operator when the handle is held by the operator, and the trigger button is used for triggering the point light source to emit light.
Preferably, the top end of the body is provided with a threaded hole, the bottom of the measuring head is provided with an external thread, and the external thread is meshed with the threaded hole to fix the measuring head and the top end of the body.
Preferably, a side surface of the body is provided with 7 point light sources, the No. 0 point light source and the No. 6 point light source are respectively positioned at the highest and the lowest of one side surface of the measuring bar 1, the connecting line of the No. 0 point light source and the No. 6 point light source is SC, the distance between the No. 3 point light source and the SC is shortest, and the distance between the No. 3 point light source and the No. 0 point light source is smaller than the distance between the No. 3 point light source and the No. 6 point; no. 4 pointolite and No. 5 pointolite all are greater than 1 pointolite and No. 2 pointolites respectively to the distance phase of No. 0 pointolite separately, and No. 1 pointolite and No. 2 pointolite set up respectively in the left and right sides of SC, and No. 4 pointolite and No. 5 pointolite set up respectively in the left and right sides of SC.
Preferably, the method for matching the feature points in the image with the point light source on the measurement bar 1 by the processor 3 according to the actual position relationship between the point light source and the point light source on the measurement bar 1 includes:
s1, extracting the first and the last feature points in the image, and setting the first and the last feature points as a No. 0 feature point and a No. 6 feature point;
s2, connecting the extracted first and last feature points to obtain a straight line SC, and solving the distance from the rest five points to the straight line SC, wherein the point with the minimum distance is the No. 3 feature point;
s3, calculating the distance between the No. 3 feature point and the first and the last feature points, wherein the point with the short distance is the No. 0 feature point, and the point with the long distance is the No. 6 feature point;
s4, calculating the distances between the other four feature points and the No. 0 feature point, and sorting according to the size, wherein the two points with the minimum distance are the No. 1 feature point and the No. 2 feature point, and the rest are the No. 4 feature point and the No. 5 feature point;
s5, if the vertical coordinate of the feature point 0 is smaller than that of the feature point 6, the process goes to S6, otherwise, the process goes to S7;
s6, comparing the horizontal coordinates of the No. 1 characteristic point with the horizontal coordinates of the No. 2 characteristic point, wherein the small point is the No. 1 characteristic point, and the large point is the No. 2 characteristic point; comparing the horizontal coordinates of the No. 4 characteristic point and the No. 5 characteristic point, wherein the small point is the No. 4 characteristic point, and the large point is the No. 5 characteristic point;
s7, comparing the horizontal coordinates of the No. 1 characteristic point with the horizontal coordinates of the No. 2 characteristic point, wherein the small point is the No. 2 characteristic point, and the large point is the No. 1 characteristic point; and comparing the horizontal coordinates of the No. 4 characteristic point and the No. 5 characteristic point, wherein the small point is the No. 5 characteristic point, and the large point is the No. 4 characteristic point.
Preferably, the measuring instrument further comprises a measuring point adapter and a straight measuring rod, the shape of the top end of the measuring point adapter is matched with a through hole, a threaded hole or a bolt to be measured on the chassis, the straight measuring rod is located at the bottom of the measuring point adapter, the shape of the bottom end of the measuring point adapter is matched with the top end of the straight measuring rod, a groove matched with the shape of a measuring head of the measuring rod 1 is formed in the bottom of the straight measuring rod, and the measuring head of the measuring rod 1 is placed during detection.
Preferably, the measuring point adapter comprises a through hole measuring point adapter, a threaded hole measuring point adapter or a bolt measuring point adapter;
the top end of the through hole measuring point adapter is conical and matched with a through hole to be measured of the chassis, and the bottom end of the through hole measuring point adapter is rod-shaped and matched with a groove in the top of the straight measuring rod;
the top end of the threaded hole measuring point adapter is columnar and is matched with a threaded hole of the chassis, a groove is formed in the bottom end of the threaded hole measuring point adapter, and the top end of the straight measuring rod is inserted into the groove for matching;
the top end of the bolt measuring point adapter is a groove matched with the shape of a bolt, the bottom end of the bolt measuring point adapter is provided with a groove, and the top end of the straight measuring rod is inserted into the groove for matching.
Preferably, the station adapter comprises through hole station adapters with various tapers, and each tapered through hole station adapter can be matched with a through hole in a set diameter range.
Preferably, the measuring instrument further comprises an L-shaped measuring head adapter rod, a groove is formed in the side face of the top end of the L-shaped measuring head adapter rod, and when the measuring instrument is used, the bottom end of the measuring point adapter is horizontally inserted into the groove to achieve matching;
the bottom end of the L-shaped measuring head switching rod is rod-shaped and is used for being vertically inserted into the groove in the top of the straight measuring rod to realize matching during use.
The photoelectric automobile chassis measuring instrument has the advantages that the photoelectric automobile chassis measuring instrument adopts a monocular vision-cooperative target to measure, and indirectly measures the position of a point to be measured of an automobile chassis by measuring the position of the cooperative target mapping rod 1, the point light source is arranged on the measuring rod 1, the position and the attitude of the measuring rod 1 are determined by utilizing the imaging of the point light source, the position of a measuring head of the measuring rod 1 is further determined, and the position of the point to be measured of the chassis is determined according to the conversion relation between a camera coordinate system and a chassis coordinate system of the imaging of the point light source, so that the detection is realized. The invention can measure the three-dimensional coordinates of the to-be-measured point of the chassis with high precision, convenience and quickness, and then compare the measured three-dimensional coordinates with the standard database of the chassis to evaluate the vehicle condition.
Drawings
FIG. 1 is a schematic diagram of the principles of the present invention;
FIG. 2 is a schematic diagram of a camera coordinate system OXYZ and a chassis coordinate system O 'X' Y 'Z';
FIG. 3 is a schematic structural diagram of the measuring rod 1;
FIG. 4 is a schematic structural view of the main body of the measuring rod 1;
FIG. 5 is a schematic diagram of the distribution of point sources on the bar 1;
FIG. 6 is a schematic perspective view of the measuring rod 1;
FIG. 7 is a schematic structural view of a through hole site adapter;
FIG. 8 is a schematic structural view of a threaded hole site adapter;
FIG. 9 is a schematic structural view of a bolt station adapter;
fig. 10 and 11 are schematic structural views of a straight measuring rod, fig. 10 is a schematic bottom end surface view of the straight measuring rod, and fig. 11 is a schematic cross-sectional view of fig. 10;
fig. 12 is a schematic structural view of an L-shaped probe adapter rod;
fig. 13 is a schematic structural view of the back surface of the L-shaped probe adapter rod;
FIG. 14 is a schematic cross-sectional view of FIG. 13;
fig. 15 is a schematic structural diagram of the front surface of the L-shaped probe adapter rod.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
The chassis measurement is performed by adopting a vision scheme in the embodiment, and a photoelectric automobile chassis measuring instrument is provided, as shown in fig. 1, and comprises a processor 3, a camera 2 and a measuring rod 1;
the measuring rod 1 comprises a body, a plurality of point light sources and a measuring head;
the measuring head is fixed on the top end of the body, when in measurement, the measuring head is in direct or indirect contact with a point to be measured on the automobile chassis, a plurality of point light sources are distributed on one side surface of the body, and the point light sources on the measuring rod 1 and the point light sources and the measuring head are in definite position relations, namely: the position and distance between each is known;
the camera 2 is opposite to the point light source on the measuring stick 1, and shoots the point light source which emits light on the body of the measuring stick 1 to obtain an image during measurement;
the processor 3 is connected with the camera 2, and when in measurement, after the vehicle to be measured is lifted by the lifter, the camera 2 is arranged at the position about 2m in front of the vehicle to be measured and is opposite to the vehicle to be measured; electrifying a camera 2 and a measuring rod 1, initializing the camera 2, judging whether the initialization of the camera 2 is successful or not, powering down the camera 2 and the measuring rod 1 if the initialization of the camera 2 is not successful, then electrifying and initializing again, and selecting four undeformed measuring points on the measuring rod 1 as datum points to establish a conversion relation between a camera coordinate system and a chassis coordinate system if the initialization of the camera 2 is successful; the camera 2 shoots a light-emitting point light source on the body of the measuring stick 1 to obtain an image; the processor 3 receives the image acquired by the camera 2, takes the light-emitting point light source as a feature, extracts a feature point in the image, positions the centroid of the feature point, matches the feature point in the image with the point light source on the measuring bar 1 according to the known actual position relationship between the point light source on the measuring bar 1 and the point light source, performs pose calculation by combining the actual position relationship between the point light source and the measuring head after matching is completed, determines the position coordinate of the measuring head under a camera coordinate system, converts the position coordinate of the measuring head under the camera coordinate system into the position coordinate under a chassis coordinate system according to the conversion relationship between the camera coordinate system and the chassis coordinate system, determines the position of a point to be measured on the automobile chassis according to the position coordinate of the measuring head under the chassis coordinate system, and completes detection. In the embodiment, the position of the point to be measured of the automobile chassis is indirectly measured by measuring the position of the coordinate target mapping rod 1; the processor 3 of the embodiment measures the three-dimensional coordinates of the point to be measured in the chassis coordinate system and compares the three-dimensional coordinates with the standard database, thereby realizing the detection and evaluation of the chassis.
The feature points are used as indispensable measurement feedback devices in monocular vision, and can be divided into an active feedback mode and a passive feedback mode according to the feedback mode. Compared with a passive feedback characteristic point, the active feedback characteristic point has high identification precision and convenient image processing by the radiation light wave characteristic of the active feedback characteristic point, and is less influenced by ambient light, so the design of the measuring instrument is carried out by adopting the active feedback characteristic point device. Meanwhile, in order to make the contrast of the characteristic points higher and facilitate the improvement of the centroid extraction precision, a near-infrared light-emitting diode is selected as a point light source, and a near-infrared sensitive camera is selected as the camera 2 and is matched with the point light source and the camera to obtain more obvious and regular image points; in order to eliminate the influence of ambient light, a band-pass filter is added in front of a camera lens, so that an ideal LED image point image is obtained. Through the influence that the cooperation ability effectual ambient light that prevents of near infrared camera, light filter and infrared LED, the effectual barycenter that promotes draws the precision, and then promotes later stage chassis coordinate measurement precision.
Due to errors caused by processing, assembling and the like of the measuring rod 1, the actual coordinates of the light spots have certain deviation from theoretical values. Therefore, the shadow camera 2 is needed to further accurately calibrate the measuring rod 1, and a coordinate system of the measuring rod 1 is established to finish accurate pose measurement. It is therefore necessary to first establish a link between the camera coordinate system and the chassis coordinate system before the chassis inspection can be started. Since the transformation of the two coordinate systems can be regarded as a rigid body transformation, the transformation of the two coordinate systems will be designed based on the rigid body transformation.
Assuming that the camera coordinate system and the chassis coordinate system are OXYZ and O 'X' Y 'Z', respectively, the coordinate origin O of the coordinate system OXYZ in the coordinate system O 'X' Y 'Z' is (t)x ty tz)TAs shown in fig. 2.
There is a point P in space, and the coordinates of the point P in the two coordinate systems are:
P＝(x y z)Tand P '═ x' y 'z')TThen the coordinate P' of the point to be measured in the coordinate system of the chassis can be represented by the coordinate P of the point in the coordinate system of the camera
P′＝R*P+T (1)
Wherein R is a rotation matrix converted by two coordinate systems, and T is a translation matrix converted by two coordinate systems.
The euler angle method and the quaternion method are commonly used as the rotation matrix representation method. The quaternion method is non-singular, simple and intuitive, and high in calculation efficiency, so that the quaternion method is selected to design the conversion relation between the camera coordinate system and the chassis coordinate system. According to the theory of quaternion, the rotation matrix R can be expressed as
Wherein,
the translation matrix T can be expressed as
The transformation of the camera coordinate system to the chassis coordinate system can then be represented by 7 elements, the first four quantities being unit quaternions and the last three quantities being translation quantities. Thus, the rigid body transformation is:
P′＝R(q)*P+(q4,q5,q6)T (4)
the coordinates of the point to be measured under the camera coordinate system and the chassis coordinate system are known, the coordinate of the point to be measured is measured by the measuring instrument, and the coordinate of the point to be measured under the chassis coordinate system can be searched in the chassis database. The establishment of the coordinate system transformation relationship becomes an inverse solution of the rotation matrix (1). Suppose that m points with known coordinates exist on the chassis of the automobile, and the coordinates of the m points in the camera coordinate system are
P1＝(x1 y1 z1)T，P2＝(x2 y2 z2)T...Pm＝(xm ym zm)T
The coordinates under the chassis coordinate system are:
P′1＝(x′1 y′1 z′1)T，P′2＝(x'2 y'2 z'2)T...P′m＝(x'm y'm z'm)T
from P1，P2...PmA matrix D of camera coordinates may be constructed,
likewise, P'1，P′2，P′3A chassis coordinate matrix D' may be constructed,
can be obtained by the formula (1),
D'＝R*D+T (7)
here, since the matrices D, D' are all 3 m matrices, the translation matrix T should also be a 3 m matrix, i.e., a
To reduce the unknown parameters, the translation matrix T is here represented by the rotation matrix R, as follows
Here, ,andrespectively by mean coordinates of the measuring apparatusAnd mean coordinates of the chassisIs composed of, i.e.
Wherein,
by substituting formula (9) for formula (7)
Can be obtained by finishing
The solution is performed by using a least square method, and an objective function (residual sum of squares function) based on equation (13) is:
to solve the minimum of equation (14), q is separately calculated0，q1，q2，q3Partial derivatives are determined and each partial derivative is made equal to 0, i.e.
Formula (15) can be written as
The quaternion q of the rotation matrix can be found from equation set (16). And (4) carrying out numerical solution on the solution by using a Newton iteration method.
After Newton iteration of a quaternion method is established, iterative solution is carried out until the k-th iteration result and the k + 1-th iteration result meet the requirements
||qk+1-qk||≤ε (18)
Wherein epsilon is a pre-designed precision requirement.
After a quaternion q of iterative solution is obtained, a rotation matrix R and a translation matrix T can be respectively obtained, and then the conversion relation between a camera coordinate system and a chassis coordinate system is determined;
in the preferred embodiment, the point light sources are not coplanar, and the measurement precision is high.
In a preferred embodiment, the measuring rod 1 of the present embodiment further includes a handle and a trigger button, the handle is fixed on the other side surface of the body and is used for the operator to perform the chassis detection by holding, the trigger button is installed on the handle, the installation position of the trigger button is opposite to the position of the thumb when the operator holds the handle, and the trigger button is used for triggering the point light source to emit light.
In the embodiment, the installation space of the LED power supply circuit and the voltage reduction module is reserved in the measuring rod 1; in the embodiment, the trigger key of the camera 2 and the trigger key of the point light source of the measuring bar 1 are the same, and when the trigger keys are pressed down, the measuring bar 1 and the camera 2 are simultaneously electrified; considering that an operator needs to hold the measuring rod 1 to go deep into the chassis of the automobile, the measuring rod 1 is required to be convenient to use and accords with human engineering.
In a preferred embodiment, a threaded hole is formed in the top end of the body in the embodiment, an external thread is formed in the bottom of the measuring head, and the external thread is meshed with the threaded hole to fix the measuring head to the top end of the body. Because later stage measurement needs to add the gauge head of different models, reserve out the screw hole at survey 1 top of stick, make things convenient for later stage gauge head installation.
The photoelectric automobile chassis measuring instrument of the embodiment adopts monocular vision-cooperation targets for measurement, and the structure of the cooperation targets (measuring rods 1) can directly influence the measurement precision of the system. In a preferred embodiment, 7 point light sources are arranged on one side surface of the body, as shown in fig. 3 to 6, the measuring stick 1 comprises 3 long pillars 11, a main body 12, 4 short pillars 13, a shell 14, a handle 15, a measuring head 16 and seven point light sources, the main body 12 and the shell 14 are assembled to form the body of the measuring stick 1, the handle 15 is mounted on the shell 14 to facilitate holding by an operator, a threaded hole is formed in the middle of the tops of the main body 12 and the shell 14, and the bottom of the measuring head 16 is screwed into the threaded hole to fix the measuring head 16 with the tops of the main body 12 and the shell 14;
in the measurement range, to ensure that 7 feature points can be effectively distinguished on the image, as shown in fig. 5, a 0 point light source and a 6 point light source are respectively located at the highest and the lowest of one side surface of the measurement bar 1, a connecting line of the 0 point light source and the 6 point light source is SC, the distance between the 3 point light source and the SC is shortest, and the distance between the 3 point light source and the 0 point light source is smaller than the distance between the 3 point light source and the 6 point light source; no. 4 pointolite and No. 5 pointolite all are greater than 1 pointolite and No. 2 pointolites respectively to the distance phase of No. 0 pointolite separately, and No. 1 pointolite and No. 2 pointolite set up respectively in the left and right sides of SC, and No. 4 pointolite and No. 5 pointolite set up respectively in the left and right sides of SC.
As shown in fig. 6, 3 long struts 11 and 4 short struts 13 are respectively disposed on one side surface of the main body 12, the 3 long struts 11 are respectively used for mounting No. 0 point light source, No. 3 point light source and No. 6 point light source, and the 4 short struts 13 are respectively used for mounting No. 1 point light source, No. 2 point light source, No. 4 point light source and No. 5 point light source;
through demand analysis and earlier stage research, the embodiment provides a measuring rod 1 which is composed of 7 characteristic points and has two planes, the size after assembly is 345 × 180 × 186mm, and the size of the measuring rod 1 is compressed as much as possible due to limited measuring space of an automobile chassis and more obstacles such as bulges and the like;
for the measuring rod 1 with 7 point light sources in the embodiment, 7 feature points are used for measurement during measurement, image points and actual points need to be in one-to-one correspondence, and then corresponding point matching is completed for next operation. However, the number of measurement points is large, and the distribution of the feature points is not in the most basic linear structure due to further space compression, so that the positions of the feature points are relatively complex.
In consideration of the field measurement situation, the automobile is generally lifted by a lifting machine, and an operator performs measurement from bottom to top; meanwhile, in order to conveniently calibrate and calibrate the measuring rod 1, the measuring rod 1 needs to be ensured to perform good light spot acquisition and measurement in the upward or downward direction. The measuring rod 1 is required to be ensured to be over against the camera 2 as much as possible in the operation process, so that the geometric position relation and the image point rule among the control points are ensured. In the present embodiment, 7 feature points are numbered from top to bottom and from left to right in sequence from 0 to 6, as shown in fig. 2 to 4.
The method for matching the characteristic points in the image shot by the camera 2 with the point light source on the measuring stick 1 by the processor 3 according to the actual position relationship between the point light source and the point light source on the measuring stick 1 specifically comprises the following steps:
s1, extracting the first and the last feature points in the image, and setting the first and the last feature points as a No. 0 feature point and a No. 6 feature point;
s2, connecting the extracted first and last feature points to obtain a straight line SC, and solving the distance from the rest five points to the straight line SC, wherein the point with the minimum distance is the No. 3 feature point;
s3, calculating the distance between the No. 3 feature point and the first and the last feature points, wherein the point with the short distance is the No. 0 feature point, and the point with the long distance is the No. 6 feature point;
s4, calculating the distances between the other four feature points and the No. 0 feature point, and sorting according to the size, wherein the two points with the minimum distance are the No. 1 feature point and the No. 2 feature point, and the rest are the No. 4 feature point and the No. 5 feature point;
s5, if the vertical coordinate of the feature point 0 is smaller than that of the feature point 6, the process goes to S6, otherwise, the process goes to S7;
s6, comparing the horizontal coordinates of the No. 1 characteristic point with the horizontal coordinates of the No. 2 characteristic point, wherein the small point is the No. 1 characteristic point, and the large point is the No. 2 characteristic point; comparing the horizontal coordinates of the No. 4 characteristic point and the No. 5 characteristic point, wherein the small point is the No. 4 characteristic point, and the large point is the No. 5 characteristic point;
s7, comparing the horizontal coordinates of the No. 1 characteristic point with the horizontal coordinates of the No. 2 characteristic point, wherein the small point is the No. 2 characteristic point, and the large point is the No. 1 characteristic point; and comparing the horizontal coordinates of the No. 4 characteristic point and the No. 5 characteristic point, wherein the small point is the No. 5 characteristic point, and the large point is the No. 4 characteristic point.
The method is suitable for the field chassis measurement environment, and is convenient for operators to carry out handheld measurement.
In a preferred embodiment, the measuring instrument of this embodiment further includes a measuring point adapter and a straight measuring rod, the top end of the measuring point adapter is matched with a through hole, a threaded hole or a bolt to be measured on the chassis, the straight measuring rod is located at the bottom of the measuring point adapter, the bottom end of the measuring point adapter is matched with the top end of the straight measuring rod, the bottom of the straight measuring rod is provided with a groove matched with the shape of the measuring head 16 of the measuring rod 1, the measuring head 16 of the measuring rod 1 is used for being placed during detection, and the structure of the straight measuring rod is as shown in fig. 10 and fig. 11.
Through the observation of the automobile chassis on the experimental site, the points to be measured of the chassis mainly comprise through holes, threaded holes, bolts and the like, and the measurement of all the points to be measured is difficult to be carried out through a single measuring head 16. Therefore, the measuring point adapters are respectively provided for different positions and different kinds of measuring points; meanwhile, in order to unify data and facilitate the handheld operation of workers, and follow the principle of interchangeability, the direct measuring rod is also used. During measurement, different measuring point adapters are selected to be arranged in the straight measuring rod and placed below the measuring point to be measured, the measuring head 16 of the measuring rod 1 is placed in a groove on the lower surface of the straight measuring rod, and chassis measurement is completed.
In a preferred embodiment, the measuring point adapter comprises a through hole measuring point adapter, a threaded hole measuring point adapter or a bolt measuring point adapter;
and measuring the through hole:
since the chassis of the vehicle contains a large number of through holes of different sizes, the design of the probe 16 cannot be performed for each size of through hole. Therefore, the measuring point adapter can be three measuring point adapters according to the aperture range to be measured, the diameters of the measuring point adapters are respectively 25mm, 35mm and 60mm, the measuring points can be respectively measured for 0-25 mm through holes, 25-35 mm through holes and 35-60 mm through holes, and the measuring of all size through holes of the chassis can be well completed; this embodiment satisfies and matches with 0 ~ 25mm through-hole, 25 ~ 35mm through-hole and 35 ~ 60mm through-hole through setting up the through-hole measurement point adapter of multiple tapering.
Measuring aiming at the threaded hole: as shown in fig. 8, the top end of the threaded hole measuring point adapter of the present embodiment is columnar and is matched with the threaded hole of the chassis, the bottom end of the threaded hole measuring point adapter is provided with a groove, and the top end of the straight measuring rod is inserted into the groove for matching; as the threaded holes of the chassis are all national standard threaded holes, the size is fixed. Therefore, it is necessary to design the probes 16 with different sizes for the screw holes;
and (3) measuring the bolt: as shown in fig. 9, the top end of the bolt measuring point adapter of the present embodiment is a groove matching with the shape of the bolt, the bottom end of the bolt measuring point adapter is provided with a groove, and the top end of the straight measuring rod is inserted into the groove for matching; because the bolt also accords with national standard, the size is fixed. Therefore, the measuring head 16 is designed respectively for bolts with different sizes;
the measuring instrument further comprises an L-shaped measuring head 16 switching rod, a groove is formed in the side face of the top end of the L-shaped measuring head 16 switching rod, and when the measuring instrument is used, the bottom end of the measuring point adapter is horizontally inserted into the groove to achieve matching;
the bottom end of the L-shaped measuring head 16 switching rod is rod-shaped and is used for being vertically inserted into the groove in the top of the straight measuring rod to realize matching when in use. Meanwhile, because the embodiment adopts monocular vision-cooperative target type measurement, the measurement rod 1 is required to be ensured to be over against the camera 2 in the measurement process so as to be convenient for collecting light spots. However, the experimental field observation shows that the distribution of the points to be measured of the automobile chassis can be divided into a horizontal plane and a vertical plane, and the measured points in the vertical plane are not beneficial to the collection of light spots; therefore, in order to facilitate the light spot collection and follow the principle of interchangeability, the present embodiment performs the design of the adapter rod of the L-shaped measuring head 16, and converts the point to be measured in the vertical plane to the measurement in the horizontal direction, as shown in fig. 12 to 15.
The measuring point adapter-measuring head 16 switching rod-straight measuring rod-measuring rod 1 can meet the measurement of all points to be measured on the chassis, saves resources, is convenient to operate, follows the principle of interchangeability, and greatly facilitates chassis measurement and vehicle condition evaluation.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.
Claims (10)
1. A photoelectric automobile chassis measuring instrument is characterized by comprising a processor, a camera and a measuring rod;
the measuring rod comprises a body, a plurality of point light sources and a measuring head;
the measuring head is fixed at the top end of the body and is used for directly or indirectly contacting with a point to be measured on the automobile chassis, and the plurality of point light sources are distributed on one side surface of the body;
the camera is opposite to the point light source on the measuring stick and used for collecting the point light source which emits light on the measuring stick body and acquiring an image;
the processor is connected with the camera and used for receiving the image acquired by the camera, taking the light-emitting point light source as a feature, extracting a feature point in the image, matching the feature point in the image with the point light source on the measuring bar according to the actual position relationship between the point light source on the measuring bar and the point light source, determining the position coordinate of the measuring head under a camera coordinate system by combining the actual position relationship between the point light source and the measuring head after matching is finished, converting the position coordinate of the measuring head under the camera coordinate system into the position coordinate under a chassis coordinate system by combining the conversion relationship between the camera coordinate system and the chassis coordinate system, and determining the position of a point to be measured on the automobile chassis according to the position coordinate of the measuring head under the chassis coordinate system to finish detection.
2. The electro-optical chassis measurement instrument of claim 1, wherein the plurality of point light sources are not coplanar.
3. The photoelectric automobile chassis measuring instrument according to claim 2, wherein the measuring bar further comprises a handle and a trigger button, the handle is fixed on the other side surface of the body and used for an operator to hold the measuring bar for automobile chassis detection, the trigger button is installed on the handle, the installation position of the trigger button is opposite to the position of the thumb when the operator holds the handle, and the trigger button is used for triggering the point light source to emit light.
4. The photoelectric automobile chassis measuring instrument according to claim 3, wherein a threaded hole is formed in the top end of the body, and an external thread is formed in the bottom of the measuring head, and is engaged with the threaded hole to fix the measuring head to the top end of the body.
5. The photoelectric automobile chassis measuring instrument according to claim 2, wherein 7 point light sources are arranged on one side surface of the body, the 0 number point light source and the 6 number point light source are respectively positioned at the highest and the lowest of one side surface of the measuring bar, the connecting line of the 0 number point light source and the 6 number point light source is SC, the distance between the 3 number point light source and the SC is shortest, and the distance between the 3 number point light source and the 0 number point light source is smaller than the distance between the 3 number point light source and the 6 number point light source; no. 4 pointolite and No. 5 pointolite all are greater than 1 pointolite and No. 2 pointolites respectively to the distance phase of No. 0 pointolite separately, and No. 1 pointolite and No. 2 pointolite set up respectively in the left and right sides of SC, and No. 4 pointolite and No. 5 pointolite set up respectively in the left and right sides of SC.
6. The electro-optical chassis measurement instrument of claim 5, wherein the processor matches the feature points in the image with the point light source on the wand based on the actual position relationship between the point light source and the point light source on the wand by:
s1, extracting the first and the last feature points in the image, and setting the first and the last feature points as a No. 0 feature point and a No. 6 feature point;
s2, connecting the extracted first and last feature points to obtain a straight line SC, and solving the distance from the rest five points to the straight line SC, wherein the point with the minimum distance is the No. 3 feature point;
s3, calculating the distance between the No. 3 feature point and the first and the last feature points, wherein the point with the short distance is the No. 0 feature point, and the point with the long distance is the No. 6 feature point;
s4, calculating the distances between the other four feature points and the No. 0 feature point, and sorting according to the size, wherein the two points with the minimum distance are the No. 1 feature point and the No. 2 feature point, and the rest are the No. 4 feature point and the No. 5 feature point;
s5, if the vertical coordinate of the feature point 0 is smaller than that of the feature point 6, the process goes to S6, otherwise, the process goes to S7;
s6, comparing the horizontal coordinates of the No. 1 characteristic point with the horizontal coordinates of the No. 2 characteristic point, wherein the small point is the No. 1 characteristic point, and the large point is the No. 2 characteristic point; comparing the horizontal coordinates of the No. 4 characteristic point and the No. 5 characteristic point, wherein the small point is the No. 4 characteristic point, and the large point is the No. 5 characteristic point;
s7, comparing the horizontal coordinates of the No. 1 characteristic point with the horizontal coordinates of the No. 2 characteristic point, wherein the small point is the No. 2 characteristic point, and the large point is the No. 1 characteristic point; and comparing the horizontal coordinates of the No. 4 characteristic point and the No. 5 characteristic point, wherein the small point is the No. 5 characteristic point, and the large point is the No. 4 characteristic point.
7. The photoelectric automobile chassis measuring instrument according to claim 4 or 6, further comprising a measuring point adapter and a straight measuring rod, wherein the top end of the measuring point adapter is matched with a through hole, a threaded hole or a bolt to be measured on the chassis in shape, the straight measuring rod is located at the bottom of the measuring point adapter, the bottom end of the measuring point adapter is matched with the top end of the straight measuring rod in shape, and a groove matched with the measuring head of the measuring rod in shape is formed in the bottom of the straight measuring rod and used for placing the measuring head of the measuring rod during detection.
8. The photoelectric automobile chassis measuring instrument according to claim 7, wherein the station adapter comprises a through hole station adapter, a threaded hole station adapter or a bolt station adapter;
the top end of the through hole measuring point adapter is conical and matched with a through hole to be measured of the chassis, and the bottom end of the through hole measuring point adapter is rod-shaped and matched with a groove in the top of the straight measuring rod; the top end of the threaded hole measuring point adapter is columnar and is matched with a threaded hole of the chassis, a groove is formed in the bottom end of the threaded hole measuring point adapter, and the top end of the straight measuring rod is inserted into the groove for matching;
the top end of the bolt measuring point adapter is a groove matched with the shape of a bolt, the bottom end of the bolt measuring point adapter is provided with a groove, and the top end of the straight measuring rod is inserted into the groove for matching.
9. The electro-optical automotive chassis measurement instrument of claim 7, wherein the site adapter comprises a plurality of tapered through hole site adapters, each tapered through hole site adapter being mateable with a through hole within a set diameter range.
10. The photoelectric automobile chassis measuring instrument according to claim 9, further comprising an L-shaped measuring head adapter rod, wherein a groove is formed in a side surface of a top end of the L-shaped measuring head adapter rod, and when the photoelectric automobile chassis measuring instrument is used, a bottom end of the measuring point adapter is horizontally inserted into the groove to achieve matching;
the bottom end of the L-shaped measuring head switching rod is rod-shaped and is used for being vertically inserted into the groove in the top of the straight measuring rod to realize matching during use.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910637416.7A CN110285756A (en) | 2019-07-15 | 2019-07-15 | Photo-electric automobile chassis measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910637416.7A CN110285756A (en) | 2019-07-15 | 2019-07-15 | Photo-electric automobile chassis measuring instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110285756A true CN110285756A (en) | 2019-09-27 |
Family
ID=68023001
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910637416.7A Pending CN110285756A (en) | 2019-07-15 | 2019-07-15 | Photo-electric automobile chassis measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110285756A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113281062A (en) * | 2021-06-07 | 2021-08-20 | 湖南汽车工程职业学院 | Intelligent recognition automobile chassis vehicle condition detection system |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5816096A (en) * | 1994-09-06 | 1998-10-06 | Southwal Pty, Ltd | Calibration frame |
| CN2722197Y (en) * | 2004-04-23 | 2005-08-31 | 天津大学 | Portable light pen three-dimensional coordinate measuring device |
| CN102062578A (en) * | 2010-12-13 | 2011-05-18 | 西安交通大学 | Handheld optical target for measuring visual coordinate and measuring method thereof |
| CN102589458A (en) * | 2011-12-22 | 2012-07-18 | 上海一成汽车检测设备科技有限公司 | Automobile chassis metal plate detecting system and method |
| CN108072320A (en) * | 2016-11-15 | 2018-05-25 | 天远三维（天津）科技有限公司 | A kind of rotatable vision measurement light pen of handle |
| CN108981564A (en) * | 2018-04-25 | 2018-12-11 | 上海大学 | A kind of light pen vision target based on active principle of luminosity |
| CN109000558A (en) * | 2018-05-30 | 2018-12-14 | 无锡黎曼机器人科技有限公司 | A kind of big visual field non-contact three-dimensional point coordinate measurement method and apparatus |
| CN109238168A (en) * | 2018-08-06 | 2019-01-18 | 大连理工大学 | Large-scale metrology part surface three dimension shape high-precision measuring method |
-
2019
- 2019-07-15 CN CN201910637416.7A patent/CN110285756A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5816096A (en) * | 1994-09-06 | 1998-10-06 | Southwal Pty, Ltd | Calibration frame |
| CN2722197Y (en) * | 2004-04-23 | 2005-08-31 | 天津大学 | Portable light pen three-dimensional coordinate measuring device |
| CN102062578A (en) * | 2010-12-13 | 2011-05-18 | 西安交通大学 | Handheld optical target for measuring visual coordinate and measuring method thereof |
| CN102589458A (en) * | 2011-12-22 | 2012-07-18 | 上海一成汽车检测设备科技有限公司 | Automobile chassis metal plate detecting system and method |
| CN108072320A (en) * | 2016-11-15 | 2018-05-25 | 天远三维（天津）科技有限公司 | A kind of rotatable vision measurement light pen of handle |
| CN108981564A (en) * | 2018-04-25 | 2018-12-11 | 上海大学 | A kind of light pen vision target based on active principle of luminosity |
| CN109000558A (en) * | 2018-05-30 | 2018-12-14 | 无锡黎曼机器人科技有限公司 | A kind of big visual field non-contact three-dimensional point coordinate measurement method and apparatus |
| CN109238168A (en) * | 2018-08-06 | 2019-01-18 | 大连理工大学 | Large-scale metrology part surface three dimension shape high-precision measuring method |
Non-Patent Citations (3)
| Title |
|---|
| 周婧 等: "基于单摄像机视觉测量系统的网络化数据融合", 《吉林大学学报(工学版)》 * |
| 薛俊诗 等: "一种高精度的非迭代位姿估计方法", 《光学学报》 * |
| 黄桂平 等: "单台相机三坐标测量的一种新方法", 《仪器仪表学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113281062A (en) * | 2021-06-07 | 2021-08-20 | 湖南汽车工程职业学院 | Intelligent recognition automobile chassis vehicle condition detection system |
| CN113281062B (en) * | 2021-06-07 | 2022-06-24 | 湖南汽车工程职业学院 | Intelligent recognition automobile chassis vehicle condition detection system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5440392A (en) | Method and system for point by point measurement of spatial coordinates | |
| CN107590835B (en) | Mechanical arm tool quick-change visual positioning system and positioning method in nuclear environment | |
| US9500469B2 (en) | Laser line probe having improved high dynamic range | |
| CN106500593A (en) | Aviation electric connector contact pin position deviation detection method | |
| CN103913117A (en) | Three-dimensional laser scanner positioning device and laser point cloud absolute positioning method | |
| CN111256592B (en) | External parameter calibration device and method for structured light sensor | |
| CN110793966A (en) | Automatic detection device and detection method for pin reduction of contacts of aviation electrical connector | |
| CN111174698B (en) | Automobile detection co-view-field-free camera global calibration system and method based on surface light field | |
| CN111256591B (en) | External parameter calibration device and method for structured light sensor | |
| CN114459345B (en) | Aircraft fuselage position and posture detection system and method based on visual space positioning | |
| CN110030923A (en) | Connector Pin needle detection system and its detection method | |
| CN110285756A (en) | Photo-electric automobile chassis measuring instrument | |
| Stroppa et al. | Stereo vision system for accurate 3D measurements of connector pins’ positions in production lines | |
| Xue et al. | Method of electronic component location, grasping and inserting based on machine vision | |
| US20230252648A1 (en) | Feature inspection system | |
| CN109059761B (en) | EIV model-based handheld target measuring head calibration method | |
| CN115861444A (en) | Visual sensor external parameter calibration method based on three-dimensional target | |
| CN115014228A (en) | Embedded extensometer based on vision measurement and double-shaft vision measurement method | |
| CN216160306U (en) | Steel member non-contact dynamic strain digital measurement system | |
| Zhang et al. | Camera calibration algorithm for long distance binocular measurement | |
| CN112798445B (en) | Bending strength detection system and method for micro-drill rod, storage medium and terminal | |
| CN114485468B (en) | Multi-axis linkage composite measurement system and full contour automated measurement method for micro parts | |
| CN118836767B (en) | Perpendicular coordinate measuring method based on structured light image | |
| Edleblute et al. | Computing the six degrees of freedom of light emitting diodes in a monocular image | |
| Kurada et al. | A trinocular vision system for close-range position sensing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20190927 |
|
| RJ01 | Rejection of invention patent application after publication |