CN113021037A

CN113021037A - Gate valve blank non-contact self-alignment clamping system and self-alignment clamping method

Info

Publication number: CN113021037A
Application number: CN202110254886.2A
Authority: CN
Inventors: 邵宣忠; 林深
Original assignee: Suzhou Mingjiang Valve Equipment Co ltd
Current assignee: Suzhou Mingjiang Valve Equipment Co ltd
Priority date: 2021-03-09
Filing date: 2021-03-09
Publication date: 2021-06-25

Abstract

The invention discloses a gate valve blank non-contact self-aligning clamping system and a self-aligning clamping method, wherein the system comprises a robot body with a robot clamping jaw device, a 3D vision system, a control system and a feeding device, the robot clamping jaw device is used for grabbing and moving a gate valve blank to be clamped, the 3D vision system is used for carrying out three-dimensional scanning on the gate valve blank, the control system is used for generating a 3D point cloud three-dimensional model, acquiring a central point pose value of a prestored standard gate valve, comparing the central point pose value with the current blank gate valve central point pose value to obtain a pose offset value relative to a robot grabbing tool coordinate system, and sending the pose offset value to a robot, the robot carries out clamping position alignment on the grabbed gate valve blank according to the pose offset value, and transfers the aligned gate valve blank to the feeding device. The gate valve clamping device performs non-contact operation through the robot, has high alignment precision, high clamping speed, safe and stable system and full automation, and can realize data tracing management of gate valve clamping.

Description

Gate valve blank non-contact self-alignment clamping system and self-alignment clamping method

Technical Field

The invention relates to the technical field of gate valve blank assembly, in particular to a gate valve blank non-contact self-alignment clamping system and a self-alignment clamping method.

Background

With the rapid development of economy and the continuous improvement of the industrial automation degree in China, equipment manufacturing industry in China is in the transformation and upgrading stage, meanwhile, the investment of the country in the fields of petroleum and natural gas, petrifaction, environmental protection, electric power, metallurgy and the like is in a continuous growth state, and the overall scale of the valve market can keep a rapid growth speed. The market demand for valves is rapidly increasing, and further, faster and higher requirements are put on the processing and production of the valves.

At present, the gate valve processing machine tool on the market is an old-fashioned turning and milling grinder, and a traditional processing technology is used. The clamping of the gate valve blank is the first process of gate valve processing and is also one of the key processes. At present, a uniform clamp is not provided for clamping a gate valve blank, a relatively complex alignment mechanism is operated manually to achieve the purpose of aligning and clamping in a matching adjustment mode at present, a three-jaw or four-jaw self-centering mode is used for the alignment mechanism, and the gate valve blank is deformed due to expansion caused by heat and contraction caused by cold of materials in a casting process due to the fact that the gate valve blank is manufactured by a casting process, so that all positioning references of the blank are damaged, and the blank materials used by each manufacturer are different from the casting process, so that the blank becomes more irregular. Due to the irregularity of the inner ring of the gate valve blank flange, when a three-claw or four-claw self-centering mode is used, the alignment and adjustment of the valve blank become very difficult, 3-point or 4-point positioning is used on an irregular circle, the sampling is relatively less, the centering precision is relatively poor, and the excessive adjustment also becomes due to the existence of a gate valve excircle end face casting head. Usually, the gate valve blank is relatively regular and can be adjusted for 2 to 3 times, but for the gate valve blank with serious deformation, the alignment function cannot be completed by the single three-jaw or four-jaw self-centering mode. As mentioned above, such a mode of operation also has the following disadvantages:

1) manual clamping efficiency is not high, and if alignment adjustment is completely performed by manual operation, sometimes an irregular blank is adjusted back and forth for 5 to 6 times;

2) the manual clamping has main pipe and objective factors, the clamping precision is not high, and the consistency is poor;

3) the manual clamping has great potential safety hazard;

4) data tracing management of gate valve clamping is not easy to realize by manual clamping;

5) the manual clamping can not realize the function expansion of clamping and can not provide more intelligent processing service for the subsequent procedures.

Therefore, in order to solve the above-mentioned disadvantages, there is a need for a gate valve blank non-contact self-aligning clamping system and a self-aligning clamping method.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a gate valve blank non-contact self-alignment clamping system and a self-alignment clamping method, which can intelligently complete high-precision operation on the premise of ensuring safety and reliability, and meanwhile, the system is simple to operate, and the technical scheme is as follows:

in one aspect, the present invention provides a gate valve blank non-contact self-aligning clamping system, comprising:

the robot comprises a robot body and a clamping mechanism, wherein the robot body is provided with a robot clamping jaw device which is used for grabbing and moving a gate valve blank to be clamped;

the 3D vision system is used for carrying out three-dimensional scanning on the gate valve blank grabbed by the robot clamping jaw device to obtain three-dimensional point cloud data;

the control system is in communication connection with the 3D vision system and the robot body, and is used for generating a three-dimensional point cloud three-dimensional model according to three-dimensional point cloud data obtained by scanning of the 3D vision system, analyzing the three-dimensional point cloud three-dimensional model to obtain axes of different side faces of the gate valve blank, and obtaining a current clamping center point coordinate and a current Euler angle value of the gate valve blank according to the axes;

the control system acquires a standard clamping central point coordinate and a standard Euler angle value of a prestored standard product, compares the standard clamping central point coordinate and the standard Euler angle value with a current clamping central point coordinate and a current Euler angle value of the gate valve blank to obtain a pose deviation value, and sends the pose deviation value to the robot body; the robot body carries out clamping position alignment on the gate valve blank grabbed by the robot body according to the pose offset value, and transfers the gate valve blank after position alignment to a feeding device;

and the feeding device is provided with a hydraulic clamping device, and the hydraulic clamping device is used for clamping a gate valve blank placed on the feeding device.

Further, gate valve blank contactless from looking for clamping system still including the extracting device who is used for depositing the gate valve blank, be equipped with at least one stores pylon and at least one material level of getting among the extracting device, under actuating mechanism's drive, the stores pylon drives different gate valve blanks and reachs in proper order get the material level.

Furthermore, a material taking position of the material taking device is provided with a centering device, and the centering device is used for roughly positioning the gate valve blank reaching the material taking position.

Further, the 3D vision system scans 5 view surfaces of the grabbed gate valve blank to obtain 5 view three-dimensional point cloud data, and the 5 view three-dimensional point cloud data are used for generating a three-dimensional point cloud three-dimensional model.

Further, the control system obtains the axes of more than two side faces of the gate valve blank in the three-dimensional point cloud three-dimensional model data in a digital mapping mode.

Particularly, after grabbing a gate valve blank, the robot clamping jaw device performs rough positioning on the gate valve blank by taking the guide diameter as a first reference surface, so that the gate valve blank and a standard product establish a constraint relation in the same positioning mode; and finding three orthogonal axes of the gate valve blank in a characteristic point line surface serving as a reference in the three-dimensional point cloud model of the gate valve blank, and taking the intersection point of the three orthogonal axes as the current clamping central point.

Further, the gate valve blank non-contact self-alignment clamping system further comprises a hydraulic station, and the hydraulic clamping device is communicated with the hydraulic station.

On the other hand, the invention provides a gate valve blank non-contact self-alignment clamping method, which comprises the following steps:

s1, moving the robot clamping jaw of the robot body to a material taking position of a material taking device, extending a certain distance along the guide diameter of a gate valve blank, and hydraulically locking the gate valve blank on the robot clamping jaw;

s2, driving a gate valve blank to move to a 3D vision system by a robot clamping jaw, and carrying out three-dimensional scanning on the gate valve blank by the 3D vision system to obtain three-dimensional point cloud data;

s3, generating a three-dimensional point cloud three-dimensional model by the control system according to the three-dimensional point cloud data, analyzing the three-dimensional point cloud three-dimensional model to obtain axes of different side surfaces of the gate valve blank, and solving a current clamping center point coordinate and a current Euler angle value of the gate valve blank according to the axes;

s4, the control system acquires the coordinate of the standard clamping central point and the standard Euler angle value of the prestored standard product, and compares the coordinate of the standard clamping central point with the coordinate of the current clamping central point of the gate valve blank and the current Euler angle value to obtain a pose offset value;

s5, the robot body carries out clamping position alignment on the gate valve blank according to the pose offset value, and the gate valve blank after clamping position alignment is transferred to a feeding device;

and S6, clamping the gate valve blank placed on the feeding device by the hydraulic clamping device on the feeding device.

Further, in step S1, the robot clamping jaw extends into a certain distance along the guiding diameter of the gate valve blank, so that the first center point of the gate valve blank coincides with the center point of the tool coordinate system of the robot clamping jaw, and the guiding diameter is used as a first reference surface to perform coarse positioning on the gate valve blank, so that the gate valve blank and the standard product both establish a constraint relationship in the same positioning manner;

in step S3, three orthogonal axes of the gate valve blank are found in the feature point line surface serving as a reference in the three-dimensional point cloud three-dimensional model, and an intersection point of the three orthogonal axes is used as a current clamping center point.

Further, in step S4, the pose deviation value includes a clamping center point coordinate deviation value and an euler angle deviation value, where the clamping center point coordinate deviation value is a difference between a standard clamping center point coordinate and a current clamping center point coordinate, and the euler angle deviation value is a difference between a standard euler angle value and a current euler angle value.

The technical scheme provided by the invention has the following beneficial effects:

a. the robot is adopted for non-contact operation in the whole process, the alignment precision is high, the clamping speed is high, the system is safe and stable, and the automation degree is high;

b. 3D model data of a gate valve blank are obtained through a vision system, accurate scanning is achieved, the system operation speed is high, and meanwhile data tracing management of gate valve clamping can be achieved;

c. compared with manual operation, the clamping function can be expanded, intelligent processing service is provided for subsequent procedures, and labor cost is saved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a gate valve blank non-contact self-alignment clamping system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a gate valve blank workpiece according to an embodiment of the present invention;

FIG. 3 is a schematic view of an ABF axis of a gate valve blank workpiece in a gate valve blank non-contact self-aligning clamping system according to an embodiment of the present invention;

FIG. 4 is a flowchart illustrating a process of finding coordinates of a center point in a non-contact self-alignment clamping system for a gate valve blank according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating a procedure of a visual alignment method in a gate valve blank non-contact self-alignment clamping system according to an embodiment of the present invention.

Wherein the reference numerals include: the method comprises the following steps of 1-hanging rack, 2-gate valve blank, 3-material taking position, 4-righting device, 5-robot clamping jaw device, 6-robot body, 7-3D vision system, 8-control system, 9-feeding device, 91-hydraulic clamping device, 11-material taking device, 13-hydraulic station, 21-guide diameter, 22-first reference surface, 23-wall thickness, 31-U-shaped port left and right side end surface, 32-left and right flange inner end surface, 33-left and right flange outer end surface and 34-U-shaped port upper plane.

Detailed Description

In order to make the technical solutions of the present invention better understood and more clearly understood by those skilled in the art, the technical solutions of the embodiments of the present invention will be described below in detail and completely with reference to the accompanying drawings. It should be noted that the implementations not shown or described in the drawings are in a form known to those of ordinary skill in the art. Additionally, while exemplifications of parameters including particular values may be provided herein, it is to be understood that the parameters need not be exactly equal to the respective values, but may be approximated to the respective values within acceptable error margins or design constraints. It is to be understood that the described embodiments are merely exemplary of a portion of the invention and not all 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. In addition, the terms "comprises" and "comprising," and any variations thereof, in the description and claims of this invention, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In one embodiment of the present invention, a gate valve blank non-contact self-aligning clamping system is provided, as shown in fig. 1, comprising a material taking device 11, a robot body 6, a 3D vision system 7, a control system 8, a feeding device 9 and a hydraulic station 13.

Extracting device 11 is used for depositing gate valve blank 2, is equipped with at least one stores pylon 1 and at least one on it and gets material level 3, wherein, stores pylon 1 drives different gate valve blanks 2 and reachs in proper order under actuating mechanism's drive get material level 3, it still is equipped with righting device 4 to get 3 departments of material level, righting device 4 is used for reaching get the gate valve blank 2 of material level 3 carries out rough positioning.

The robot body 6 is provided with a robot clamping jaw device 5, and the robot clamping jaw device 5 is used for grabbing and moving the gate valve blank 2 to be clamped; the 3D vision system 7 is used for carrying out three-dimensional scanning on the gate valve blank 2 grabbed by the robot clamping jaw device 5 to obtain three-dimensional point cloud data; the control system 8 is in communication connection with the 3D vision system 7 and the robot body 6, and the control system 8 is used for processing the three-dimensional point cloud data and controlling the robot body 6 to adjust correspondingly.

The feeding device 9 is provided with a hydraulic clamping device 91, and the hydraulic clamping device 91 is used for clamping the gate valve blank 2 placed on the feeding device 9; the hydraulic station 13 is in communication with the hydraulic clamping device 91, and the hydraulic station 13 is configured to provide powered support to the hydraulic clamping device 91.

Specifically, control system 8 sends and gets material signal extremely robot 6, robot 6 receives and gets material instruction and then moves to get material level 3 department, robot clamping jaw device 5 snatchs through after 4 coarse positioning of righting gate valve blank 2 and send and get material and accomplish signal extremely control system 8, control system 8 receives and accomplishes signal and then to robot 6 sends scanning instruction, robot 6 receives scanning instruction and then moves to 3D vision system 7 department, 3D vision system 7 scans the gate valve blank 2 who is snatched, will obtain three-dimensional point cloud data send to control system 8.

It should be noted that, as shown in fig. 2, when the robot gripper 5 performs the gripping operation, the robot gripper 5 extends a certain distance along the first reference plane 22 of the guide diameter 21 of the gate valve blank 2, and then the robot gripper 5 locks the gate valve blank 2 under the power support of the hydraulic station 13, so that the first positioning of the gate valve blank 2 is realized. Furthermore, the 3D vision system 7 may scan 5 views (front view, rear view, left view, right view, top view) of the gate valve blank 2 to obtain three-dimensional point cloud data of the 5 views.

The control system 8 generates a three-dimensional point cloud three-dimensional model by splicing according to the three-dimensional point cloud data, analyzes the three-dimensional point cloud three-dimensional model to obtain the axes of different side surfaces of the gate valve blank 2, and the current clamping central point coordinate and the current Euler angle value of the gate valve blank 2 are obtained according to the axis, by acquiring the coordinate of the standard clamping central point of the pre-stored standard product and the standard Euler angle value, the control system 8 compares the coordinate of the standard clamping central point with the coordinate of the current clamping central point of the gate valve blank 2 and the current Euler angle value to obtain a pose deviation value, and sends it to the robot body 6, the robot body 6 then according to the pose offset value, and (4) carrying out position alignment on the gate valve blank 2 grabbed by the gate valve blank grabbing device, transferring the gate valve blank 2 subjected to position alignment to a feeding device 9, and completing the non-contact self-alignment clamping operation of the gate valve blank 2. It should be noted that the control system 8 obtains the axis ABF of the gate valve blank 2 in the three-dimensional point cloud data by adopting a digital mapping mode, respectively verifies respective machining allowances, and uses the value with the minimum variance or standard deviation of distances to all axial planes as a reference axis, so as to obtain the current clamping center point coordinate and the pose offset value with higher relative accuracy, thereby providing relatively accurate data support for subsequent alignment operation.

In one embodiment of the present invention, a gate valve blank non-contact self-aligning clamping system is provided, as shown in fig. 1-2, comprising a robot body 6, a 3D vision camera system 7, a material taking device 11, a feeding device 9, a hydraulic station 13 and a PC control system 8.

The gate valve blank 2 is stored in a three-dimensional warehouse, the robot body 6 runs to a specific material taking position 3 in the three-dimensional warehouse, extends into a guide path 22 of the gate valve blank 2 through a robot clamping jaw device 5, grasps the gate valve blank 2 after positioning, realizes the first coarse positioning of the gate valve blank 2 after the grasping is completed, then the robot body 6 moves to a 3D vision camera system 7 to carry out three-dimensional scanning, obtains three-dimensional point cloud data of 5 views after respectively scanning 5 view planes (front view, rear view, left view, right view and top view), and then is spliced into a 3D point cloud three-dimensional model after being processed by the PC control system 8, so that real objects correspond to digital simulation one by one, and then the PC control system 8 is utilized to carry out data analysis on the 3D point cloud three-dimensional model of the gate valve blank 2 and adopts figures for surveying and mapping, the method comprises the steps of finding out axis ABFs of different surfaces, quickly and accurately finding out a clamping central point coordinate and an Euler angle value of a gate valve blank 2, comparing the clamping central point coordinate and the Euler angle value of a standard product (the clamping central point coordinate pose of the standard product is the origin pose of an Ot tool coordinate system pre-established by a robot), calculating an actual pose offset value, transmitting the pose offset value to a robot body 6, compensating and correcting the robot body 6 through a self motion control model after the pose offset value is obtained, and correctly placing the gate valve blank 2 into a clamping central point of a feeding device 9, so that unmanned automatic alignment is realized, and after alignment, a clamping function can be realized by operating a hydraulic clamping device, and thus, one-time non-contact automatic alignment and clamping of the gate valve blank 2 are completed.

In one embodiment of the present invention, a gate valve blank non-contact self-aligning clamping system is provided, as shown in fig. 1-2, which comprises a robot body 6, a 3D vision camera system 7, a material taking device 11, a feeding device 9, a hydraulic station 13 and a PC control system 8, which are six major body panels.

The 3D vision camera system 7 is installed on a flat ground and is subjected to shock absorption treatment. The robot body 6 is arranged on the smooth ground, so that the firmness and reliability of the robot are guaranteed. The material taking device 11 and the material feeding device 9 are fixedly arranged on the left side and the right side of the robot respectively.

The connection and communication of each plate of the system adopt a communication mode, a network framework of a system component uses an industrial Ethernet bus, and communication protocols respectively adopt an international general Profinet protocol and a Modbus TCP protocol.

The PC control system sends a material taking signal to the robot body 6, the robot body 6 moves to a material taking position 3 of the material taking device 11, a gate valve blank of the material taking position 3 is roughly positioned and hung in the material taking position 3 through the centering device 4, the robot body 6 extends into a certain distance along a guide diameter 21 of the gate valve blank by a first reference surface 22 through the robot clamping jaw device 5, and then the gate valve blank is hydraulically locked, so that the gate valve blank is positioned on the robot body 6 for the first time by the first reference surface of the gate valve blank. The accuracy and consistency of the coarse positioning of the gate valve blank on the robot body 6 with the first reference surface 22 is effectively ensured by the centering device 4 and the robot gripper arrangement 5.

After the robot body 6 finishes material taking, a material taking completion signal is sent to the PC control system 8, the PC control system 8 receives the material taking completion signal and sends a scanning motion instruction to the robot body 63D, the robot body 6 then runs to a scanning position of a visual scanning device to scan 5 view planes (front, back, left, right and upper views) respectively, after the scanning is completed, the PC control system 8 performs splicing and merging, after the splicing is completed, a complete 3D point cloud three-dimensional model image is obtained, and the PC control system 8 performs digital mapping and sampling analysis on the 3D point cloud simulation model image.

Then, the coordinates of the three orthogonal Axes (ABF) of the gate valve blank 2 and their intersection points, i.e. the center point, need to be found. After the robot clamping jaw device 5 grabs the gate valve blank 2, the gate valve blank 2 is roughly positioned on the tail end of the robot body 6 by taking the guide diameter as a first reference surface 22. For the standard, a tool coordinate system Ot is also established at the end of the robot body 6 with the guide diameter 21 of the gate valve blank 2 as the first reference plane 22. The gate valve blank 2 and the standard establish a constraint relationship in the same positioning manner. After the constraint is good, three orthogonal Axes (ABF) of the gate valve blank 2 can be found in a certain characteristic point line surface which can be used as a reference in the 3D point cloud model of the gate valve blank 2.

3-4, the central axis A perpendicular to the U-shaped mouth upper end surface 34 is found with reference to the U-shaped mouth left and right end surfaces 31 of the gate valve blank 2¹Theoretically speaking, the axis A¹Axis of workpiece for standardA is coincident, but because the rough positioning of the clamping jaws causes errors such as swinging of the pose of the blank and deformation of the blank, and the blank has deviation, the axis A is actually arranged on the blank¹As a first reference, and at the same time, the middle axis A with the two inner end surfaces 32 of the flange as the reference can be found according to the inner end surfaces 32 of the flange of the gate valve blank 2²From axis A¹And axis A²In between, a median axis A can be found³When the axis A is neutral³Within the deviation of the first reference A of the standard, we divide the axis A in half³For the first axis A of the blank we are looking for, if the axis A is centered³When the standard substance is not within the deviation value of the first standard substance A, the maximum tolerance value of the first standard substance A of the standard substance is taken as the axis A of the blank, and then the axis A is taken as the axis A of the blank³Feed axis A²And outputting the deviation value to a machine tool, correcting the error value of the flange end faces by using the machine tool, ensuring the thickness uniformity of the two flange end faces during processing, verifying the processing allowance of the two end faces of the flange after finding the axis A of the blank, and if the processing allowance is met, finishing the alignment of the axis A, and if the processing allowance is not met, finding the axis A again by using the method.

When the axis A is found, the second axis B is found¹. The outer end faces 33 of the left flange and the right flange of the gate valve blank 2 can find respective central points and are connected into a line, and then the axis B can be found¹At this time, the axis A and the axis B of the blank¹Not necessarily orthogonal, passing through axis A and axis B¹The intersection point of the two axes is an axis B perpendicular to the axis A²Then along the axis B²Verifying the machining allowance of the excircle of the end face of the flange for the center line shaft, and if the machining allowance is met, determining the center line axis B at the moment²If the axis B is not satisfied, the axis B is found again in the above method.

When the axis B is found, the third axis F is found. An axis parallel to the upper end surface 34 of the U-shaped opening is found in the center of the axis A and the axis B, and the axis is the axis F¹If this axis F is present¹The machining allowance of the thickness of the U-shaped opening is met, and the axis F at the moment¹That is, the axis F we are looking for, if not, re-findingThe above method is used for finding.

After three axes ABF of the gate valve blank 2 are found, the intersection point of the ABF axes is the clamping central point of the gate valve blank 2, the point is taken as the original point, ABF is a three-orthogonal axis ZXY, and a gate valve blank clamping central point coordinate system O1 is established. And comparing the central point coordinate O1 of the gate valve blank with the clamping central point coordinate Ot of the standard product to obtain the actual position and the Euler angle deviant, thereby realizing the automatic alignment function of the gate valve blank.

After the robot body 6 obtains the offset pose data, compensation correction is carried out through a motion control model of the robot body, then the clamping center point O1 coordinate system of the gate valve blank is placed in the central position O2 coordinate system of the loading device for superposition, and alignment placement is completed. And then, the gate valve blank is compressed by using a hydraulic device, and a back-off instruction is sent to the robot body 6 after the gate valve blank is compressed, and the robot body 6 backs to the original state to wait for the material taking position 3, so that a clamping process for 3D scanning and alignment of the gate valve blank is completed.

After the 3D point cloud simulation model diagram is established, digital surveying and mapping of other functions can be carried out on the gate valve blank, the size of each wall thickness 23 of the gate valve blank can be measured, the casting quality of the gate valve blank can be evaluated, the important guiding significance for gate valve blank casting can be achieved, and the important guiding significance can be fed back to a casting manufacturer to guide production in real time; the method is used for surveying and mapping the size of the dead head of the valve blank, and can provide the starting point data and the cutting amount data of the rough milling dead head for the next rough milling process, so that the self-adaptive intelligent processing mode of the rough milling process is realized.

In one embodiment of the invention, the invention also provides a method of visual alignment. As shown in fig. 5, the steps of the visual alignment method are as follows:

(1) calibrating the 3D camera (solving internal parameters, external parameters and distortion parameters of the camera);

in image measurement or machine vision application, calibration of camera parameters is a very critical link, and the accuracy of a calibration result and the stability of an algorithm directly influence the accuracy of a result generated by the operation of a camera.

The camera calibration method comprises the following steps: a conventional camera calibration method, an active vision camera calibration method, and a camera self-calibration method.

The calibration of the internal reference of the camera is generally finished after the camera leaves a factory and basically calibrated, and people only need to calibrate the external reference.

The aim of calibration is to realize all motion data and object position and attitude information in a coordinate system.

The robot holds the standard in a fixed pose moving along Z, producing a set of profile data for each 2 mm. Since the profiler data is only X, Z, and no Y, assuming that Y for the first profile is 0, the Y coordinate for the second profile is 2, … …, and so on, a profiler scan is obtained. And finding the circle center in the scanned gray scale image to obtain the coordinates (x, y) of the characteristic point of the standard component, and obtaining z data according to the gray scale value. Thereby obtaining the coordinates (x, y, z) of the characteristic point in the coordinate system of the contourgraph. And carrying out affine transformation on the characteristic point coordinates in the contourgraph coordinate system and the robot coordinate system coordinates, and solving to obtain an affine transformation matrix T. The T is the transfer matrix of the profiler coordinates to world coordinate system coordinates. Obtaining T, the calibration is completed.

(2) Establishing a robot tool coordinate system (X) with a standard clamping central point as an origin¹Y¹Z¹)；

The constraint relation between the standard product and the blank is that the robot clamping jaw is used for grabbing and positioning by taking a first reference A as a reference, and the constraint relation by taking the first reference A as a reference is established between the robot clamping jaw and the blank after positioning.

The center of the clamping jaw is coincided with the original tool center point of a flange plate of a sixth axis of the robot, a certain distance (the distance between the center point of the standard product and the center point of the flange plate) of a Z axis of a flange plate tool coordinate system is deviated, and a robot tool coordinate system (X) with the clamping center point of the standard product as the original point is established¹Y¹Z¹) I.e. the Ot coordinate system.

(3) Calibrating the coordinate of the center point of the standard product by using the robot and the standard tool to give a robot pose value of which the coordinate of the center point of the feeding device is completely superposed;

and (3) placing the standard tool on the feeding device, and after the standard tool is hydraulically locked, enabling the position and the posture of the central point of the standard tool for placing the workpiece of the feeding device to coincide.

A cylindrical convex correction workpiece is arranged on a flange plate of the robot, the robot adjusts the position and the posture to ensure that the correction workpiece is completely matched with a disc type concave circular hole on a standard tool, and then the robot follows a tool coordinate system X¹Y¹Z¹Moving a certain distance (after anastomosis, the tool coordinate system X)¹Y¹Z¹The difference value of the Z-direction distance from the standard tool can be calculated by the drawing sizes of the tool and the correcting workpiece), and at this time, the robot pose value is the robot pose value of the center point coordinate of the standard product completely coinciding with the center point coordinate of the feeding device, namely the O2 coordinate system.

(4) Calibrating the projection poses of 5 scanning positions of the robot;

the center point can be found in a symmetrical mode, the center can also be found in non-orthographic projection scanning, but in an asymmetrical part, the size is deformed to some extent due to the non-orthographic projection scanning, and the precision measurement is influenced. Therefore, to align the pose of the projection scanning robot, a cube arranged on a flange of the robot can be used for correcting the pose of the 5 scanning positions of the robot.

(5) The robot is matched with a camera to scan 5 view planes of the gate valve blank to generate three-dimensional point cloud data;

(6) splicing the three-dimensional point cloud data of the 5 view planes into a 3D point cloud three-dimensional model by utilizing a PC control system;

(7) finding out three orthogonal Axes (ABF) of a gate valve blank and intersection points (a clamping central point of the gate valve blank) of the three orthogonal axes;

(8) establishing a Cartesian rectangular coordinate system (X) with a gate valve blank clamping central point as an origin²Y²Z²)；

After three orthogonal Axes (ABF) and their central intersection points are found, a Cartesian rectangular coordinate system (X) with the intersection points as the origin can be established²Y²Z²) The coordinate system is also a Cartesian rectangular coordinate system (X) with the clamping central point of the gate valve blank as the origin²Y²Z²) I.e., the O1 coordinate system.

(9) Calculating the relative pose deviation value of the gate valve blank central point coordinate system and the robot tool coordinate system

X²Y²Z²Coordinate system and X¹Y¹Z¹After the coordinate system is determined, X²Y²Z²Relative to X¹Y¹Z¹The pose deviation can be calculated according to the rotation matrix, and the XYZABC 6 data deviation values of the two tool coordinate systems can be calculated.

(10) Outputting the pose deviation value to the robot;

and the PC control system transmits the offset.X, the offset.Y, the offset.Z, the offset.A, the offset.B and the offset.C to the robot through communication.

(11) And the robot moves to the clamping position to perform relative pose deviation according to the obtained relative tool coordinate system pose deviation value, so that the gate valve blank is automatically aligned.

In an embodiment of the present invention, the present invention further provides a gate valve blank non-contact self-alignment clamping method, which includes the following steps:

s5, the robot body carries out clamping position alignment on the gate valve blank according to the pose offset value, and the gate valve blank after position alignment is transferred to a feeding device;

In the embodiment of the invention, firstly, in step S1, the robot clamping jaw extends into a certain distance along the guide diameter of the gate valve blank, so that a constraint relation is established between the clamping center point of the gate valve blank and the tool coordinate system Ot of the robot clamping jaw; secondly, in the step S3, the control system obtains axes ABF of different side surfaces of the gate valve blank in the three-dimensional point cloud data in a digital mapping mode, and the coordinates of the current clamping center point of the gate valve blank are obtained by using the intersection points of three orthogonal axes ABF; thirdly, in step S4, the pose deviation value includes a clamping central point coordinate deviation value and an euler angle deviation value, where the clamping central point coordinate deviation value is a difference value between a standard clamping central point coordinate and a current clamping central point coordinate, and the euler angle deviation value is a difference value between a standard euler angle value and a current euler angle value.

The idea of the embodiment of the gate valve blank non-contact self-alignment clamping method and the working process of the gate valve blank non-contact self-alignment clamping in the embodiment belong to the same idea, and the whole content of the embodiment of the gate valve blank non-contact self-alignment clamping system is incorporated into the embodiment of the gate valve blank non-contact self-alignment clamping method in a full-text reference manner and is not described again.

Compared with the prior art, the invention has the following outstanding and beneficial technical effects that firstly, the framework is simpler, the modularized operation is easy to realize, a complex clamping mechanism is not required to be designed, the production and manufacturing period is shorter, and the maintenance is relatively simpler and faster; secondly, a high-speed 3D visual scanning and high-speed PC control system operation processing mode is adopted, the clamping speed depends on the scanning speed, the alignment speed depends on the operation speed of the PC control system, the whole process is automatic and unmanned, the clamping speed is fast and stable, and the clamping efficiency is higher; moreover, the robot automatically grabs and discharges materials, the machine vision 3D scans and measures, the PC control system surveys and draws the operation, the whole process is operated automatically, the alignment is convenient, the measurement is stable and reliable, the precision is high, and the whole clamping precision is higher; in addition, the robot and vision replace the manpower, so that the non-contact alignment clamping is realized, the safety, the reliability and the effectiveness are realized, the labor cost is also saved, the gate valve product alignment clamping of multiple varieties and batches can be realized, and the flexibility degree is higher; more importantly, the invention has outstanding expression in the aspects of visualization, data traceability, digitization and intellectualization.

Through visual scanning imaging, the data of the whole 3D model of the gate valve blank can be established, the gate valve blank can be visually presented in a PC control system in three dimensions, and required relevant size data such as coordinates of a clamping central point, the wall thickness of the blank, machining starting point data of a casting head and the like can be obtained after surveying and mapping analysis of the PC control system and stored in the PC control system, so that identity marking can be realized, and intelligent data processing service can be provided for the next machining process.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The utility model provides a gate valve blank contactless is from looking for clamping system, its characterized in that includes:

the gate valve clamping device comprises a robot body (6) and a clamping mechanism, wherein the robot body is provided with a robot clamping jaw device (5), and the robot clamping jaw device (5) is used for grabbing and moving a gate valve blank (2) to be clamped;

the 3D vision system (7) is used for carrying out three-dimensional scanning on the gate valve blank (2) grabbed by the robot clamping jaw device (5) to obtain three-dimensional point cloud model data;

the control system (8) is in communication connection with the 3D vision system (7) and the robot body (6), and the control system (8) is used for generating a three-dimensional point cloud three-dimensional model according to three-dimensional point cloud data obtained by scanning of the 3D vision system (7), analyzing the three-dimensional point cloud three-dimensional model to obtain axes of different sides of the gate valve blank (2), and obtaining a current clamping center point coordinate and a current Euler angle value of the gate valve blank (2) according to the axes;

the control system (8) acquires a standard clamping central point coordinate and a standard Euler angle value of a prestored standard product, compares the standard clamping central point coordinate and the standard Euler angle value with a current clamping central point coordinate and a current Euler angle value of the gate valve blank (2) to obtain a pose deviation value, and sends the pose deviation value to the robot body (6); the robot body (6) performs clamping position alignment on the gate valve blank (2) grabbed by the robot body according to the pose deviation value, and transfers the gate valve blank (2) subjected to position alignment to a feeding device (9);

the feeding device (9) is provided with a hydraulic clamping device (91), and the hydraulic clamping device (91) is used for clamping a gate valve blank (2) placed on the feeding device (9).

2. The gate valve blank non-contact self-aligning clamping system according to claim 1, further comprising a material taking device (11) for storing the gate valve blank (2), wherein at least one hanging rack (1) and at least one material taking position (3) are arranged in the material taking device (11), and the hanging rack (1) drives different gate valve blanks (2) to sequentially reach the material taking position (3) under the driving of the driving mechanism.

3. The gate valve blank non-contact self-aligning clamping system according to claim 2, characterized in that a centering device (4) is provided at the take-out position (3) of the take-out device (11), the centering device (4) being configured to coarsely position the gate valve blank (2) reaching the take-out position (3).

4. The gate valve blank non-contact self-aligning clamping system according to claim 1, wherein the 3D vision system (7) scans 5 view planes of the gripped gate valve blank (2) to obtain three-dimensional point cloud data of the 5 view planes, and the 5-view three-dimensional point cloud data is used for generating a gate valve three-dimensional point cloud three-dimensional model.

5. The gate valve blank non-contact self-aligning clamping system according to claim 1, characterized in that the control system (8) uses digital mapping to obtain the axes of more than two sides of the gate valve blank (2) in a three-dimensional point cloud three-dimensional model.

6. The gate valve blank non-contact self-aligning clamping system according to claim 5, wherein after the robot clamping jaw device (5) grabs the gate valve blank (2), the gate valve blank (2) is roughly positioned by taking the guide diameter as a first reference surface, so that the gate valve blank (2) and the standard product are all in the same positioning mode to establish a constraint relation; and then finding three orthogonal axes of the gate valve blank (2) in a characteristic point line surface serving as a reference in the three-dimensional point cloud three-dimensional model of the gate valve blank (2), and taking the intersection point of the three orthogonal axes as the current clamping central point.

7. The gate valve blank non-contact self-aligning clamping system of claim 1 further comprising a hydraulic station (13), said hydraulic clamping means (91) being in communication with said hydraulic station (13).

8. A gate valve blank non-contact self-alignment clamping method is characterized by comprising the following steps:

9. The gate valve blank non-contact self-alignment clamping method according to claim 8, wherein in step S1, the robot clamping jaw extends into a certain distance along the guiding diameter of the gate valve blank, so that the first center point of the gate valve blank coincides with the center point of the tool coordinate system of the robot clamping jaw, and the guiding diameter is used as a first reference surface to perform coarse positioning on the gate valve blank, so that the gate valve blank and the standard product are both in a constraint relationship in the same positioning manner;

10. The gate valve blank non-contact self-alignment clamping method according to claim 8, wherein in step S4, the pose offset value comprises a clamping center point coordinate offset value and an euler angle offset value, wherein the clamping center point coordinate offset value is a difference value between a standard clamping center point coordinate and a current clamping center point coordinate, and the euler angle offset value is a difference value between a standard euler angle value and a current euler angle value.