WO2023185550A1

WO2023185550A1 - Visual measurement guiding device, method and system for cylinder nested assembly centering

Info

Publication number: WO2023185550A1
Application number: PCT/CN2023/082806
Authority: WO
Inventors: 张东升; 杨达; 王硕; 丁柯
Original assignee: 上海大学绍兴研究院; 上海大学
Priority date: 2022-03-28
Filing date: 2023-03-21
Publication date: 2023-10-05
Also published as: CN114674249B; CN114674249A

Abstract

A visual measurement guiding device for cylinder nested assembly centering, relating to the technical field of optical measurement. The device comprises a plurality of measuring units and an integrated processor; the measuring units are used for obtaining target images when a preset condition is satisfied; the target image is an image of the position of a butt joint end of a reference cylinder and the position of a butt joint end of a measured cylinder; the preset condition is that the plurality of measuring units are distributed on the periphery of the reference cylinder and are all located on a plane perpendicular to the measured cylinder; the plane is a plane where the cross section of the butt joint end of the reference cylinder is located; the integrated processor is used for processing the target images obtained by the plurality of measuring units on the basis of a triangulation method, determining a deviation between the butt joint end of the reference cylinder and the butt joint end of the measured cylinder, and outputting a pose adjusting instruction on the basis of the deviation; the pose adjusting instruction is an instruction for moving the measured cylinder. The present invention has the advantages of non-contact, low cost, high speed, high precision, high automation degree, etc. Further disclosed is a visual measurement guiding method for cylinder nested assembly centering.

Description

A visual measurement guidance device, method and system for cylinder nesting and pairing

Technical field

The present invention relates to the technical field of optical measurement, and in particular to a visual measurement guidance device, method and system for cylinder nesting and pairing.

Background technique

Cylindrical structural parts are widely used in pipeline engineering, metallurgy, aerospace manufacturing and other industries. Both ends of cylindrical structural parts often require complex connection, assembly or sealing work, especially in the special equipment manufacturing industry. The coaxial butt assembly process of segmented cylindrical structural parts is directly related to the quality of the overall equipment. In order to meet the needs of factory automation production lines for docking accuracy and production efficiency, there is an urgent need to develop a technical method for guiding cylindrical structural parts to achieve high-precision coaxial docking.

In the final assembly process of the aerospace manufacturing industry, there are generally two existing assembly methods: (1) The traditional docking assembly mode is to place the two cabin sections to be docked on the brackets of the docking assembly truck. Observe with the human eye and manually adjust the height of the bracket and the angle of the cabin to ensure that the screws, positioning pins and positioning pin holes on the docking surfaces of the two cabins match accurately. This assembly mode requires the participation of multiple people, and the docking efficiency depends on the experience and level of the operator. (2) Use a laser tracker (LTS) as a measurement method, and use a 3-DOF positioner or a 6-DOF symmetrical parallel mechanism Stewart platform to adjust the pose of the workpiece. This method is used in some small cabin sections. During docking and assembly, each assembly requires repeating the process of placing the cabin sections on the parallel platform, installing the target ball, adjusting the attitude for docking, disassembling the target ball, and moving the cabin sections. This is obviously more tedious than manual assembly and consumes the operator's physical strength. Therefore, the above technology is not suitable for continuous assembly on a production line.

Contents of the invention

The purpose of the present invention is to provide a visual measurement guidance device, method and system for cylinder nesting and pairing, which has the advantages of non-contact, low cost, fast speed, precision and high degree of automation.

In order to achieve the above objects, the present invention provides the following solutions:

In a first aspect, an embodiment of the present invention provides a visual measurement guidance device for cylinder nesting and pairing, including: multiple measurement units and an integrated processor;

The measurement unit is used to obtain a target image when a preset condition is met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is a plurality of The measurement units are distributed around the periphery of the reference cylinder, and a plurality of the measurement units are located on a plane perpendicular to the measured cylinder; the plane is where the cross section of the butt end of the reference cylinder is located. flat;

The integrated processor is configured to process target images obtained by multiple measurement units based on triangulation, determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, and A posture adjustment instruction is output based on the deviation; the posture adjustment instruction is an instruction to move the measured cylinder.

Optionally, the visual measurement guidance device includes at least three measurement units, and each measurement unit includes an image sensor and a light source.

Optionally, the image sensor in the measurement unit is a camera; the light source in the measurement unit is a linear light source; In terms of processing the target images acquired by multiple measurement units based on triangulation and determining the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, the integrated processor , used for:

In the image coordinate system, based on the pixel coordinates of the line light source on the reference cylinder and the measured cylinder, the pixel-level vertical distance and the pixel-level lateral distance are calculated; the pixel-level vertical distance is The axial movement distance of the measured cylinder under the image coordinate system, and the pixel-level lateral distance is the radial height difference between the measured cylinder and the reference cylinder;

Based on the pixel-level vertical distance, the pixel-level lateral distance and the triangulation method, determine the actual vertical distance and the actual lateral distance between the reference cylinder and the measured cylinder in the reference coordinate system; The reference coordinate system takes the center of the circle of the end surface of the reference cylinder as the origin, the longitudinal axis of the reference cylinder as the Z axis, the horizontal axis of the reference cylinder as the X axis, and the vertical axis of the reference cylinder as the X axis. The direct axis is the three-dimensional coordinate system established by the Y axis;

Taking the origin of the reference coordinate system as the first circle center coordinate, and based on the actual vertical distance and the actual lateral distance, calculate the second circle center coordinate under the reference coordinate system; the first circle center coordinate is the The center coordinate of the cross section of the butt end of the reference cylinder; the second center coordinate is the center coordinate of the cross section of the butt end of the measured cylinder;

Calculate the circle center deviation according to the first circle center coordinate and the second circle center coordinate;

Taking the Z-axis direction of the reference coordinate system as the axial vector of the reference cylinder, calculate the axial vector of the measured cylinder in the reference coordinate system based on the second circle center coordinate, and based on the The axial vector of the reference cylinder and the axial vector of the measured cylinder are used to calculate the axial deviation;

Wherein, the deviation between the butt end of the reference cylinder and the butt end of the measured cylinder includes center deviation and axial deviation.

Optionally, the image sensor is provided with an imaging lens; based on the pixel-level vertical distance, the pixel-level lateral distance and the triangulation method, it is determined that the reference cylinder and the reference cylinder are in a reference coordinate system. In terms of the actual vertical distance and actual lateral distance between the measured cylinders, the integrated processor is used to:

According to the formula Calculate the actual vertical distance between the reference cylinder and the measured cylinder at each of the measurement unit positions;

Calculate the actual lateral distance between the reference cylinder and the measured cylinder at each measurement unit position according to the formula ΔS=k·Δs;

Among them, ΔD represents the actual vertical distance, Δd represents the pixel-level lateral distance, L represents the working distance of each measurement unit, l represents the image distance of each measurement unit, and θ represents the reference value of the light emitted by the light source. The incident angle of the cylinder surface, α is the angle between the optical axis of the camera and the imaging lens;

ΔS represents the actual lateral distance, Δs represents the pixel-level vertical distance, and k represents the ratio between the image pixel distance determined when calibrating the camera and the actual distance.

Optionally, in terms of outputting posture adjustment instructions based on the deviation, the integrated processor is configured to:

Determine whether the deviation condition is met; the deviation condition includes: the axial deviation is less than the vector detection threshold and the circle center deviation is less than the circle center detection threshold;

If not, the pose adjustment instruction is output and the target image is updated.

Optionally, the posture adjustment instruction includes a first adjustment instruction and a second adjustment instruction; in terms of outputting the posture adjustment instruction based on the deviation, the integrated processor is configured to:

Determine whether the axial deviation is less than the vector detection threshold, and obtain the first judgment result;

If the first judgment result indicates that the axial deviation is less than the vector detection threshold, then it is judged whether the circle center deviation is less than the circle center detection threshold, and a second judgment result is obtained;

If the first judgment result indicates that the axial deviation is greater than or equal to the vector detection threshold, a first adjustment instruction is output and the target image is updated; the first adjustment instruction is used to adjust the position of the target image in the reference coordinate system. Move the cylinder under test in the direction of the X axis;

If the second judgment result indicates that the circle center deviation is greater than or equal to the circle center detection threshold, a second adjustment instruction is output, and the target image is updated; the second adjustment instruction is used to adjust the center point of the circle in the reference coordinate system. Move the measured cylinder in the X-axis direction and the Y-axis direction.

Optionally, a mobile component is also included;

In the working state, the cylinder under test is placed on the moving component, and the moving component is used to move the cylinder under test according to the received posture adjustment instruction.

In a second aspect, embodiments of the present invention provide a visual measurement guidance method in cylinder nesting and pairing, including:

The target image is obtained when the preset conditions are met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is that multiple measurement units are distributed in the reference cylinder The periphery of the body, and the plurality of measurement units are located on a plane perpendicular to the measured cylinder; the plane is the plane where the cross section of the butt end of the reference cylinder is located;

Process the target images acquired by multiple measurement units based on triangulation, determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, and output pose adjustment instructions based on the deviation ; The posture adjustment instruction is an instruction to move the measured cylinder.

In a third aspect, embodiments of the present invention provide a visual measurement guidance system for cylinder nesting and pairing, including:

A target image acquisition unit is used to acquire a target image when a preset condition is met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is a plurality of measurements Units are distributed around the periphery of the reference cylinder, and a plurality of the measurement units are located on a plane perpendicular to the measured cylinder; the plane is the plane where the cross-section of the butt end of the reference cylinder is located;

A pose adjustment instruction determination unit is configured to process multiple target images acquired by the measurement units based on triangulation, determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, and A posture adjustment instruction is output based on the deviation; the posture adjustment instruction is an instruction to move the measured cylinder.

According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

The present invention provides a visual measurement guidance device, method and system for cylinder nesting and pairing. Compared with the traditional visual method, the present invention does not require markers to be pasted on the cylinder to be measured, and the measurement unit is simple to install and Small size enables contactless measurement. The invention can accurately output adjustment instructions through image processing technology and triangulation method to achieve efficient and precise alignment of the reference cylinder and the measured cylinder. Therefore, the present invention has the advantages of high speed, high precision, high degree of automation, etc., and is suitable for continuous assembly on the production line. As a non-contact optical measurement technology, the present invention is simple to operate, has high precision and is very economical. Therefore, it is very suitable for the centering measurement and guidance of various circular cross-section cylindrical objects.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a structural block diagram of the visual measurement guidance device in the barrel nesting assembly provided by the embodiment of the present invention;

Figure 2 is a schematic diagram of the selection of the reference coordinate system and the layout of the measurement units provided by the embodiment of the present invention;

Figure 3 is a schematic diagram of the triangulation method provided by the embodiment of the present invention;

Figure 4 is a schematic structural diagram of a mobile component provided by an embodiment of the present invention;

Figure 5 is a schematic diagram of posture adjustment logic provided by an embodiment of the present invention;

Figure 6 is a physical diagram of the measurement unit provided by the embodiment of the present invention;

Figure 7 is a test result diagram provided by the embodiment of the present invention;

Figure 8 is a flow chart of the visual measurement guidance method in cylinder nesting and pairing provided by an embodiment of the present invention;

Figure 9 is a structural diagram of the visual measurement guidance system in the cylinder nesting assembly provided by the embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

With the continuous advancement of science and technology, the use of computer measurement methods such as laser or image has become one of the hot spots in the field of automation research. With the rapid development of various application fields, triangulation method suitable for diffuse reflective surfaces has gradually become a widely used non-contact measurement method. Triangulation is a non-contact measurement method that utilizes triangulation principles and is widely used in industrial production sites. Its main advantages are simple optical path design, high precision, fast speed, strong real-time processing capabilities, flexible use, and wide application. . The distance measurement principle of the triangulation method is to use the structured light emitted by the light source to project on the surface of the cylinder to be measured, forming a light spot. Place a lens at another angle, and the light spot is imaged onto the photodetector through the lens. When the cylinder to be measured faces each other, When the rangefinder is displaced, the imaging position of the light spot on the photodetector will also change relatively. The displacement of the measured cylinder can be obtained by obtaining the displacement of the photodetector spot position.

Based on the distance measurement principle of triangulation, the present invention proposes a brand-new measurement and guidance system, that is, a visual measurement guidance device, method and system for cylinder nesting and pairing, which has the characteristics of non-contact, low cost, speed It has the advantages of speed, precision and high degree of automation.

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Embodiment 1

The purpose of the embodiments of the present invention is to propose a multi-camera visual measurement guidance device based on triangulation method in view of the existing technical defects and equipment limitations, as well as the urgent need for circular cross-section cylinder nesting and matching technology. , that is, a visual measurement guidance device for cylinder nesting and pairing. This device is a non-contact optical measuring device that can be applied to the alignment measurement of various cylindrical or cylindrical-like structures.

As shown in Figure 1, an embodiment of the present invention provides a visual measurement guidance device for cylinder nesting and pairing, including Includes: multiple measurement units and an integrated processor;

The measurement unit is used to obtain a target image when a preset condition is met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is a plurality of The measurement units are distributed around the periphery of the reference cylinder, and a plurality of the measurement units are located on a plane perpendicular to the measured cylinder; the plane is where the cross section of the butt end of the reference cylinder is located. flat.

The integrated processor is configured to process target images obtained by multiple measurement units based on triangulation, determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, and A posture adjustment instruction is output based on the deviation; the posture adjustment instruction is an instruction to move the measured cylinder, that is, the measured cylinder reaches the designated position through the posture adjustment instruction, thereby realizing the reference cylinder and the measured cylinder. The measuring cylinder nesting set is being matched.

As a preferred implementation, the visual measurement guidance device provided by the embodiment of the present invention includes at least three measurement units, and each measurement unit includes an image sensor and a light source, and in the working state, the three measurement units The measuring units are distributed in the circumferential direction of the reference cylinder.

As a preferred implementation manner, the image sensor in the measurement unit according to the embodiment of the present invention is a camera; the light source in the measurement unit is a linear light source.

As shown in Figure 2, the target image includes a first circle (A in Figure 2) and a second circle (B in Figure 2); the first circle is used to represent the docking end position of the reference cylinder. , the second circle is used to represent the position of the butt end of the measured cylinder.

In terms of controlling the measurement unit and camera calibration, the integrated processor is used for:

Open n measurement units in sequence so that the target image is displayed on the display screen in real time. Adjust the camera posture, aperture and focus so that the reference cylinder and the measured cylinder are clearly imaged in the field of view. Calibrate each camera to obtain the proportional relationship k between the image pixel distance and the real distance.

Based on the triangulation method, the target images obtained by multiple measurement units are processed to determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder. The integrated processor is used to:

In the image coordinate system, based on the pixel coordinates of the line light source on the reference cylinder and the measured cylinder, the pixel-level vertical distance and the pixel-level lateral distance are calculated; the pixel-level vertical distance is The axial movement distance of the measured cylinder under the image coordinate system, and the pixel-level lateral distance is the radial height difference between the measured cylinder and the reference cylinder.

Based on the pixel-level vertical distance, the pixel-level lateral distance and the triangulation method, determine the actual vertical distance and the actual lateral distance between the reference cylinder and the measured cylinder in the reference coordinate system; The reference coordinate system takes the center of the circle of the end surface of the reference cylinder as the origin, the longitudinal axis of the reference cylinder as the Z axis, the horizontal axis of the reference cylinder as the X axis, and the vertical axis of the reference cylinder as the X axis. The direct axis is the three-dimensional coordinate system established by the Y axis.

Taking the origin of the reference coordinate system as the first circle center coordinate, and based on the actual vertical distance and the actual lateral distance, calculate the second circle center coordinate under the reference coordinate system; the first circle center coordinate is the The coordinates of the circle center of the cross section of the butt end of the reference cylinder; the second circle center coordinate is the center coordinate of the cross section of the butt end of the measured cylinder.

Calculate the circle center deviation according to the first circle center coordinate and the second circle center coordinate.

Taking the Z-axis direction of the reference coordinate system as the axial vector of the reference cylinder, calculate the axial vector of the measured cylinder in the reference coordinate system based on the second circle center coordinate, and based on the The axial vector of the reference cylinder and the axial vector of the measured cylinder are used to calculate the axial deviation.

Further, the image sensor is provided with an imaging lens; based on the pixel-level vertical distance, the pixel-level lateral distance and the triangulation method, determine the distance between the reference cylinder and the measured cylinder in the reference coordinate system Between the actual vertical distance and the actual lateral distance, the integrated processor is used to:

According to the formula Calculate the actual vertical distance between the reference cylinder and the measured cylinder at each measurement unit position, as shown in Figure 3.

The actual lateral distance between the reference cylinder and the measured cylinder at each measurement unit position is calculated according to the formula ΔS=k·Δs(2).

Among them, ΔD represents the actual vertical distance, Δd represents the pixel-level lateral distance, L represents the working distance of each measurement unit, l represents the image distance of each measurement unit, and θ represents the reference value of the light emitted by the light source. The incident angle of the cylinder surface, α, is the angle between the optical axis of the camera and the imaging lens.

Further, based on the actual vertical distance and the actual lateral distance, calculate the second circle center coordinate in the reference coordinate system, and the integrated processor is used to:

Determine the coordinate value of the docking end of the reference cylinder in the reference coordinate system, that is, the coordinates on the circle of one end of the reference cylinder close to the measured cylinder can be obtained from the relative position of the measurement unit, as:
( _RA ·cosγ _i , _RA ·sinγ _i ,0)(i＝1,2,3...)(3)

Among them, γ _i is the angle between the camera axis and the X-axis of the reference coordinate system, R _A is the radius of the cross section of the docking end of the reference cylinder, and i is the point on the docking end.

Based on the actual vertical distance, the actual lateral distance and the determined coordinate value of the docking end of the reference cylinder, calculate the coordinate value of the docking end of the measured cylinder in the reference coordinate system, that is:
(( _RA -ΔD _i )·cosγ _i , ( _RA -ΔD _i )·sinγ _i ,ΔS _i )(i=1,2,3...) (4).

Based on the calculated coordinate value of the butt end of the measured cylinder, the second circle center coordinate is determined.

Taking three evenly distributed measurement units as an example, set the coordinates on the butt end of the measured cylinder to (x _i , y _i , z _i ) (i=1, 2, 3). From the equal distances from the three points to the coordinates of the center of the space circle, we can get:

By combining the three equations and eliminating R _A at the same time, we get:

Express the above three equations as:

From equation (7), we can get a system of linear algebraic equations about the spatial coordinates of the center of the circle. The solution of the coordinates of the center of the circle is:

Thus, the coordinates of the center of the circle of the measured cylinder are obtained, that is, the coordinates of the second center of the circle are (x _A , y _A , z _A ).

When the measurement unit n is greater than three, any three measurement units can be selected from the n measurement units to calculate the corresponding circle center coordinates of the measured cylinder. After multiple measurements, the least squares method is used to fit the accurate circle center coordinates.

Further, according to the second circle center coordinate, calculate the axial vector of the measured cylinder in the reference coordinate system, and the integrated processor is used to:

Taking three evenly distributed measurement units as an example, set the measured coordinates on the end of the measured cylinder close to the reference cylinder, that is, the coordinates on the butt end of the measured cylinder are (x _i , y _i , z _i ) (i=1,2,3). Suppose the normal vector of the cross-section of the butt end of the cylinder under test is (a, b, c), then
(a,b,c)＝((x ₂ -x ₁ ,y ₂ -y ₁ ,z ₂ -z ₁ )×(x ₃ -x ₁ ,y ₃ -y ₁ ,z ₃ -z ₁ ))( 9);

It can be calculated from equation (9):

The central axis of the reference cylinder is the normal equation passing through the center of the circle on the surface of the reference cylinder, so the axis equation is:

When the measurement unit n is greater than three, any three measurement units can be selected from the n measurement units to calculate the corresponding axis equation of the measured cylinder. After multiple measurements, the least squares method is used to fit the accurate axis equation.

Further, based on the deviation, the integrated processor outputs a posture adjustment instruction, and the integrated processor is used to:

Determine whether the deviation condition is met; the deviation condition includes: the axial deviation is less than the vector detection threshold and the circle center deviation is less than the circle center detection threshold; if not, output the posture adjustment instruction and update the target image; if yes, then stop working.

Alternatively, the posture adjustment instruction includes a first adjustment instruction and a second adjustment instruction; outputting the posture adjustment instruction based on the deviation, the integrated processor is used to:

Determine whether the axial deviation is less than the vector detection threshold, and obtain a first judgment result; if the first judgment result indicates that the axial deviation is less than the vector detection threshold, then determine whether the circle center deviation is less than the circle center detection threshold, Obtain a second judgment result; if the first judgment result indicates that the axial deviation is greater than or equal to the vector detection threshold, then output a first adjustment instruction and update the target image; the first adjustment instruction is used to Move the measured cylinder in the X-axis direction of the reference coordinate system.

If the second judgment result indicates that the circle center deviation is greater than or equal to the circle center detection threshold, a second adjustment instruction is output, and the target image is updated; the second adjustment instruction is used to adjust the center point of the circle in the reference coordinate system. Move the measured cylinder in the X-axis direction and Y-axis direction. If the second judgment result indicates that the circle center deviation is less than the circle center detection threshold, the operation is stopped.

As a preferred implementation, the visual measurement guidance device in the barrel nesting set provided by the embodiment of the present invention also includes a moving component as shown in Figure 4.

As shown in Figure 6, appropriate vector detection threshold θ _n and circle center detection threshold θ _c are set according to the measurement accuracy requirements. First adjust the axis vector of the cylinder being measured. In the three-dimensional rectangular coordinate system with the datum plane as the XOY plane, according to the measured point coordinates of the end circle of the butt end of the cylinder under test, calculate the normal vector of the end surface passing through the center of the circle and use it as the axis vector of the cylinder under test until The components of the axis vector in each coordinate axis are smaller than the preset vector detection threshold θ _n . Then compare the center positions of the reference cylinder and the measured cylinder. According to the measured point coordinates of the end circle at the butt end of the cylinder under test, the coordinate difference between the center of the end surface circle and the center of the reference plane is calculated, and the motor in the moving assembly is driven to adjust the cylinder under test in parallel. Until the axis vector and circle center deviation of the measured cylinder are less than the threshold, the adjustment is completed.

Now, taking a circular cross-section cylinder as an example, we will illustrate the operation process of a visual measurement guidance device in nested matching of circular cross-section cylinders as follows:

1. Take one of the two circular cross-section cylinders as the reference cylinder, and the other circular cross-section cylinder as the measured cylinder. A datum coordinate system Oxyz is set on the datum cylinder. The longitudinal axis of the datum cylinder is the Z axis, the vertical axis is the Y axis, and the horizontal axis is the X axis.

2. Arrange 3 measuring units in a plane perpendicular to the cross section of the butt end of the reference cylinder. The actual object is as shown in Figure 6. That is, the 3 measuring units are fixed on the steel frame around the reference cylinder. The angles between them are all 120°, as shown in Figure 2.

3. First adjust the working distance between the measurement unit and the reference cylinder, then adjust the focal length of the camera in the measurement unit, and then calibrate the camera. Specifically: first turn on the light source, then adjust the camera aperture and focus so that the measured cylinder and The reference cylinder is clearly imaged in the field of view, so that when the light source illuminates the docking end position of the reference cylinder and the docking end of the measured cylinder, the position of the docking end of the reference cylinder and the docking end position of the measured cylinder can be obtained. image; then calibrate the camera through the known size of the workpiece on the surface of the reference cylinder to obtain the proportional relationship between the image pixel distance and the actual distance.

4. Establish communication with the motor.

5. Unify the coordinates of the end of the reference cylinder obtained by each measurement unit under the coordinate system set in step 1, and calculate the coordinates of the corresponding points at the end of the reference cylinder.

6. Start each measuring unit respectively, measure the relative docking position of the reference cylinder and the end of the measured cylinder, and measure the vertical distance Δd and lateral distance Δs of the two line segments. Use triangulation method to obtain the true vertical distance ΔD between the measured cylinder and the reference cylinder. The real lateral distance ΔS is calculated based on the proportional relationship between the image pixel distance and the actual distance. Then calculate the coordinates of the corresponding point on the end of the measured cylinder based on the coordinates of the corresponding point on the end of the reference cylinder in step 5 and ΔD and ΔS.

7. Calculate the axis equation and circle center of the measured cylinder based on the n point coordinates of the end face of the measured cylinder measured by the measuring unit, and calculate the deviation based on the axis equation and the circle center; then adjust the corresponding motor and motor drive based on this deviation two Each bracket continuously adjusts the posture of the cylinder under test so that the axis and center of the cylinder under test are consistent with the reference cylinder, completing one measurement and alignment guidance.

8. Repeat steps 6-7. When the measured coaxiality between the reference cylinder and the measured cylinder is less than the assembly error, complete the visual alignment guidance. The measurement is finished. The motor drives the cylinder under test to move forward, completing the docking between the two reference cylinders and the cylinder under test. The docking results are shown in Figure 7.

Embodiment 2

As shown in Figure 8, an embodiment of the present invention provides a method for visual measurement guidance in cylinder nesting and pairing, including:

Step 100: Obtain a target image when the preset conditions are met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is that multiple measurement units are distributed at all locations. The periphery of the reference cylinder, and the plurality of measurement units are located on a plane perpendicular to the measured cylinder; the plane is the plane where the cross section of the butt end of the reference cylinder is located.

Step 200: Process the target images acquired by multiple measurement units based on the triangulation method, determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, and output a bit based on the deviation. Posture adjustment instruction; the posture adjustment instruction is an instruction to move the measured cylinder.

Embodiment 3

As shown in Figure 9, an embodiment of the present invention provides a visual measurement guidance system for cylinder nesting and pairing, including:

The target image acquisition unit 300 is used to acquire a target image when a preset condition is met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is a plurality of Measuring units are distributed around the periphery of the reference cylinder, and multiple measurement units are located on a plane perpendicular to the measured cylinder; the plane is the plane where the cross-section of the butt end of the reference cylinder is located. .

The posture adjustment instruction determination unit 400 is configured to process a plurality of target images obtained by the measurement units based on the triangulation method, and determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, And output a posture adjustment instruction based on the deviation; the posture adjustment instruction is an instruction to move the measured cylinder.

Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on its differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. As for the methods and systems disclosed in the embodiments, since they correspond to the devices disclosed in the embodiments, the description is relatively simple. For relevant details, please refer to the device description.

This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and the core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the present invention There will be changes in the specific implementation methods and application scope of the ideas. In summary, the contents of this description should not be construed as limitations of the present invention.

Claims

A visual measurement guidance device for cylinder nesting and pairing, which is characterized in that it includes: multiple measurement units and an integrated processor;

The measurement unit is used to obtain a target image when a preset condition is met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is a plurality of The measurement units are distributed around the periphery of the reference cylinder, and a plurality of the measurement units are located on a plane perpendicular to the measured cylinder; the plane is where the cross section of the butt end of the reference cylinder is located. flat;

The integrated processor is configured to process target images obtained by multiple measurement units based on triangulation, determine the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, and Output a posture adjustment instruction based on the deviation; the posture adjustment instruction is an instruction to move the measured cylinder;

The image sensor in the measurement unit is a camera; the light source in the measurement unit is a line light source; after processing the target images obtained by multiple measurement units based on the triangulation method, the docking end of the reference cylinder is determined In terms of the deviation from the docking end of the cylinder being measured, the integrated processor is used for:

In the image coordinate system, based on the pixel coordinates of the line light source on the reference cylinder and the measured cylinder, the pixel-level vertical distance and the pixel-level lateral distance are calculated; the pixel-level vertical distance is The axial movement distance of the measured cylinder under the image coordinate system, and the pixel-level lateral distance is the radial height difference between the measured cylinder and the reference cylinder;

Based on the pixel-level vertical distance, the pixel-level lateral distance and the triangulation method, determine the actual vertical distance and the actual lateral distance between the reference cylinder and the measured cylinder in the reference coordinate system; The reference coordinate system takes the center of the circle of the end surface of the reference cylinder as the origin, the longitudinal axis of the reference cylinder as the Z axis, the horizontal axis of the reference cylinder as the X axis, and the vertical axis of the reference cylinder as the X axis. The direct axis is the three-dimensional coordinate system established by the Y axis;

Taking the origin of the reference coordinate system as the first circle center coordinate, and based on the actual vertical distance and the actual lateral distance, calculate the second circle center coordinate under the reference coordinate system; the first circle center coordinate is the The center coordinate of the cross section of the butt end of the reference cylinder; the second center coordinate is the center coordinate of the cross section of the butt end of the measured cylinder;

Calculate the circle center deviation according to the first circle center coordinate and the second circle center coordinate;

Taking the Z-axis direction of the reference coordinate system as the axial vector of the reference cylinder, calculate the axial vector of the measured cylinder in the reference coordinate system based on the second circle center coordinate, and based on the The axial vector of the reference cylinder and the axial vector of the measured cylinder are used to calculate the axial deviation;

Wherein, the deviation between the butt end of the reference cylinder and the butt end of the measured cylinder includes center deviation and axial deviation.
A visual measurement guidance device in a barrel nesting set according to claim 1, characterized in that the visual measurement guidance device includes at least three measurement units, and each measurement unit includes Image sensor and light source.
A visual measurement guidance device for cylinder nesting and pairing according to claim 1, wherein the image sensor is provided with an imaging lens; based on the pixel-level vertical distance, the pixel level lateral distance and triangulation method to determine the actual vertical distance and actual lateral distance between the reference cylinder and the measured cylinder in the reference coordinate system, the integrated processor is used to:

According to the formula Calculate the reference cylinder at each measurement unit position The actual vertical distance between the body and the measured cylinder;

Calculate the actual lateral distance between the reference cylinder and the measured cylinder at each measurement unit position according to the formula ΔS=k·Δs;

Among them, ΔD represents the actual vertical distance, Δd represents the pixel-level lateral distance, L represents the working distance of each measurement unit, l represents the image distance of each measurement unit, and θ represents the reference value of the light emitted by the light source. The incident angle of the cylinder surface, α is the angle between the optical axis of the camera and the imaging lens;

ΔS represents the actual lateral distance, Δs represents the pixel-level vertical distance, and k represents the ratio between the image pixel distance determined when calibrating the camera and the actual distance.
A visual measurement guidance device for cylinder nesting and pairing according to claim 1, characterized in that, in terms of outputting posture adjustment instructions based on the deviation, the integrated processor is used to:

Determine whether the deviation condition is met; the deviation condition includes: the axial deviation is less than the vector detection threshold and the circle center deviation is less than the circle center detection threshold;

If not, the pose adjustment instruction is output and the target image is updated.
A visual measurement guidance device for cylinder nesting and pairing according to claim 1, wherein the posture adjustment instruction includes a first adjustment instruction and a second adjustment instruction; In terms of outputting posture adjustment instructions, the integrated processor is used to:

Determine whether the axial deviation is less than the vector detection threshold, and obtain the first judgment result;

If the first judgment result indicates that the axial deviation is less than the vector detection threshold, then it is judged whether the circle center deviation is less than the circle center detection threshold, and a second judgment result is obtained;

If the first judgment result indicates that the axial deviation is greater than or equal to the vector detection threshold, a first adjustment instruction is output and the target image is updated; the first adjustment instruction is used to adjust the position of the target image in the reference coordinate system. Move the cylinder under test in the direction of the X axis;

If the second judgment result indicates that the circle center deviation is greater than or equal to the circle center detection threshold, a second adjustment instruction is output, and the target image is updated; the second adjustment instruction is used to adjust the center point of the circle in the reference coordinate system. Move the measured cylinder in the X-axis direction and the Y-axis direction.
A visual measurement guidance device for cylinder nesting and pairing according to claim 1, 4 or 5, characterized in that it also includes a moving component;

In the working state, the cylinder under test is placed on the moving component, and the moving component is used to move the cylinder under test according to the received posture adjustment instruction.
A visual measurement guidance method in cylinder nesting and pairing, which is characterized by including:

The measurement unit obtains a target image when the preset conditions are met; the target image is an image of the docking end position of the reference cylinder and the docking end position of the measured cylinder; the preset condition is that multiple measurement units are distributed in the The periphery of the reference cylinder, and the plurality of measurement units are located on a plane perpendicular to the measured cylinder; the plane is the plane where the cross section of the butt end of the reference cylinder is located;

The integrated processor processes the target images obtained by multiple measurement units based on triangulation, determines the deviation between the docking end of the reference cylinder and the docking end of the measured cylinder, and outputs based on the deviation Posture adjustment instructions; the posture adjustment instructions are instructions for moving the measured cylinder;

The image sensor in the measurement unit is a camera; the light source in the measurement unit is a line light source; the target images obtained by multiple measurement units are processed based on the triangulation method to determine the connection end of the reference cylinder and The tested The deviation between the butt ends of the cylinder specifically includes:

In the image coordinate system, based on the pixel coordinates of the line light source on the reference cylinder and the measured cylinder, the pixel-level vertical distance and the pixel-level lateral distance are calculated; the pixel-level vertical distance is The axial movement distance of the measured cylinder under the image coordinate system, and the pixel-level lateral distance is the radial height difference between the measured cylinder and the reference cylinder;

Based on the pixel-level vertical distance, the pixel-level lateral distance and the triangulation method, determine the actual vertical distance and the actual lateral distance between the reference cylinder and the measured cylinder in the reference coordinate system; The reference coordinate system takes the center of the circle of the end surface of the reference cylinder as the origin, the longitudinal axis of the reference cylinder as the Z axis, the horizontal axis of the reference cylinder as the X axis, and the vertical axis of the reference cylinder as the X axis. The direct axis is the three-dimensional coordinate system established by the Y axis;

Taking the origin of the reference coordinate system as the first circle center coordinate, and based on the actual vertical distance and the actual lateral distance, calculate the second circle center coordinate under the reference coordinate system; the first circle center coordinate is the The center coordinate of the cross section of the butt end of the reference cylinder; the second center coordinate is the center coordinate of the cross section of the butt end of the measured cylinder;

Calculate the circle center deviation according to the first circle center coordinate and the second circle center coordinate;

Taking the Z-axis direction of the reference coordinate system as the axial vector of the reference cylinder, calculate the axial vector of the measured cylinder in the reference coordinate system based on the second circle center coordinate, and based on the The axial vector of the reference cylinder and the axial vector of the measured cylinder are used to calculate the axial deviation;

Wherein, the deviation between the butt end of the reference cylinder and the butt end of the measured cylinder includes center deviation and axial deviation.