Workpiece measuring method and welding system

Abstract

Compared with the prior art, the measuring time of the measuring object can be shortened, and the measuring object can be measured with high precision. A workpiece measurement method for measuring a workpiece configured from a columnar member and a partition plate and held by a positioner includes: an acquisition step of acquiring point group data of a surface of the workpiece held by the positioner, the point group data being captured from a predetermined direction; a detection step for specifying a portion in which the distribution of the point group data changes in the three-dimensional coordinate system of the positioner, and detecting the portion as a boundary position between the columnar member and the separator; and a derivation step for deriving the number of the columnar members and the number of the separators constituting the workpiece on the basis of the boundary positions detected in the detection step.

Description

Technical Field

[0001] The invention relates to a workpiece measuring method and a welding system. Background Art

[0002] In the past, a component to be welded (hereinafter also referred to as a "workpiece") was prepared at a predetermined position, and a welding robot was used to weld the workpiece. In such a case, for the purpose of automatic welding of the workpiece, it is sought to easily grasp the shape and setting state of the workpiece and achieve labor saving. When grasping the position of the workpiece, for example, point group data obtained by a ToF (Time of Flight) sensor is used.

[0003] For example, as an example of measuring the size of a workpiece in a welding system, Patent Document 1 discloses a structure in which a measurement program is selected according to the shape of the object to be measured, and the measurement is performed by a sensor provided in a welding robot. In addition, as an example of measuring an object to be measured, Patent Document 2 discloses a structure in which three-dimensional data of an object to be measured, etc., set on a glass table, is measured by a laser measuring device, and the three-dimensional shape of the entire object to be measured observed from multiple viewing angles is obtained.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-162554

[0007] Patent Document 2: Japanese Patent Application Publication No. 2010-276485

[0008] For example, in the method of Patent Document 1, it is envisaged to use a touch sensor or the like as a sensor. At this time, when the sensor is actuated according to the measurement program, if the distance between the measurement start position based on the sensor and the actual setting position of the measured object is far, useless measurement action occurs and the measurement takes time. In addition, in Patent Document 1, it is necessary to switch the measurement program according to the shape of the measured object, and the selection of the measurement program needs to be done manually. In addition, if a setting error of the workpiece occurs in the positioner, an erroneous size may be measured. On the other hand, in the structure of Patent Document 2, multiple sensors are required, so the device becomes costly, and there is also a concern about the large size of the device. Summary of the invention

[0009] Problems to be solved by the invention

[0010] An object of the present invention is to shorten the measurement time of a measurement object compared with the related art and to measure the structure of the measurement object with high accuracy.

[0011] Solutions to Solve Problems

[0012] In order to solve the above-mentioned problems, the present invention has the following structure. That is, a workpiece measuring method is used to measure a workpiece, wherein the workpiece is composed of a columnar member and a spacer and is held by a positioner.

[0013] The workpiece measuring method comprises:

[0014] an acquisition step of acquiring point group data of the surface of the workpiece held by the locator and photographed from a predetermined direction;

[0015] a detection step of determining, in the three-dimensional coordinate system of the locator, a portion where the distribution of the point group data changes, and detecting the portion as a boundary position between the columnar member and the partition plate; and

[0016] The derivation step derives the number of the columnar members and the spacers constituting the workpiece based on the boundary position detected in the detection step.

[0017] Another aspect of the present invention has the following structure. That is, a welding system, wherein:

[0018] The welding system has:

[0019] A welding robot having a welding torch;

[0020] A welding control device, which controls the welding robot;

[0021] a positioner that holds a workpiece composed of a columnar member and a partition plate; and

[0022] A sensor that captures the workpiece from a predetermined direction to obtain point group data.

[0023] The welding control device comprises:

[0024] an acquisition unit that acquires point group data of the surface of the workpiece held by the positioner, which is photographed by the sensor from the predetermined direction;

[0025] a detection unit that determines, in the three-dimensional coordinate system of the locator, a portion where the distribution of the point group data changes, and detects the portion as a boundary position between the columnar member and the partition; and

[0026] A calculation unit calculates the size and position of the workpiece based on the boundary position detected by the detection unit.

[0027] Effects of the Invention

[0028] According to the present invention, the measurement time of the measurement object can be shortened compared with the related art, and the structure of the measurement object can be measured with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an external perspective view showing the overall outline of a welding system according to one embodiment of the present invention.

[0030] Figure 2 This is an external perspective view showing a structural example of a workpiece as a measurement target according to one embodiment of the present invention.

[0031] Figure 3 This is a block diagram showing a configuration example of a welding control device according to one embodiment of the present invention.

[0032] Figure 4 This is a block diagram showing an example of the functional configuration of a welding control device according to one embodiment of the present invention.

[0033] Figure 5 This is a schematic diagram for explaining a structural example of a workpiece according to one embodiment of the present invention.

[0034] Figure 6 This is a schematic diagram for explaining measurement of a workpiece according to one embodiment of the present invention.

[0035] Fig. 7A This is a graph showing an example of measurement results of a workpiece according to one embodiment of the present invention.

[0036] Figure 7B This is a graph showing an example of measurement results of a workpiece according to one embodiment of the present invention.

[0037] Fig. 8A This is a schematic diagram for explaining correction of installation errors of workpieces according to one embodiment of the present invention.

[0038] Figure 8B This is a schematic diagram for explaining correction of installation errors of workpieces according to one embodiment of the present invention.

[0039] Fig. 9 This is a flowchart of a welding process according to one embodiment of the present invention.

[0040] Description of reference numerals:

[0041] 1…Welding equipment

[0042] 2…Positioner

[0043] 3…Welding robots

[0044] 4…Arm

[0045] 5…Welding torch

[0046] 6…Welding wire

[0047] 7…Sensors

[0048] 8…Welding control device

[0049] 9…Controller

[0050] 10… Camera

[0051] 11, 12…Mobile unit

[0052] 21… Column

[0053] 22…Separator

[0054] 23…Slope

[0055] 100…Welding system

[0056] W…workpiece. DETAILED DESCRIPTION

[0057] Hereinafter, the method for implementing the present invention will be described with reference to the accompanying drawings and the like. It should be noted that the embodiment described below is an embodiment for illustrating the present invention and is not intended to limit the interpretation of the present invention. In addition, all the structures described in each embodiment are not limited to the structures necessary to solve the problems of the present invention. In addition, in each of the accompanying drawings, the corresponding relationship is indicated by marking the same reference numerals for the same constituent elements. It should be noted that in the present embodiment, expressions such as "first" and "second" are only used to distinguish from other elements and are not intended to be interpreted as specific elements in a limiting manner. Therefore, these expressions are appropriately replaced according to the combination, quantity, etc. of the constituent elements.

[0058] <First embodiment>

[0059] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0060] [Structure of welding system]

[0061] Figure 1 The welding system 100 is a perspective view showing the overall outline of a welding system 100 to which the workpiece measuring method of the present embodiment can be applied. The welding system 100 includes a welding device 1, a positioner 2, a welding robot 3, a welding control device 8, a controller 9, and a camera 10 (first sensor).

[0062] The welding device 1 is configured to weld the workpiece W held by the positioner 2 by the welding robot 3. The welding control device 8 controls the welding robot 3 via the controller 9. At this time, the welding control device 8 can also control the relative position of the welding robot 3 and the workpiece W by controlling the moving units 11 and 12. In addition, the welding control device 8 controls the rotation of the positioner 2 and the shooting of the camera 10. It should be noted that in this embodiment, the case where the welding control device 8 performs comprehensive welding control is described, but it can also be configured to set an independent control device for each device, and they cooperate to perform welding.

[0063] The workpiece W of this embodiment is as follows Figure 2 The workpiece W is held by the positioner 2 and is arranged to be rotatable around a predetermined axis. The positioner 2 is a panel that holds the workpiece W and fixes the workpiece W in the axial direction. In addition, the positioner 2 has a rotation drive unit that causes the workpiece W to rotate in the circumferential direction. Figure 1 Although a cantilever type positioner 2 that holds one end of the workpiece W is described in the specification, a double support type positioner that holds both ends of the workpiece W may be used.

[0064] The welding robot 3 is configured to have various functions for welding various welding joints of the workpiece W held by the positioner 2. For example, an arc welding robot can be used as the welding robot 3. The welding robot 3 includes a multi-jointed arm 4, a welding torch 5 supported by the arm 4, a welding wire 6 fed to the front end of the welding torch 5, and a sensor 7 (second sensor) capable of detecting the position of the front end of the welding torch 5.

[0065] The sensor 7 is arranged around the front end of the welding robot 3, and by moving the welding robot 3, the coordinates of the preset detection position in the workpiece W are measured as measurement data. The sensor 7 can be any sensor as long as it can measure the coordinates of the workpiece W as measurement data, and can be a non-contact position detection sensor such as a laser, a contact position detection sensor such as a touch sensor, etc. In this embodiment, the case where the sensor 7 provides a touch sensing function for grasping the position and shape of the workpiece W is described. In addition, the measurement data measured by the sensor 7 may include coordinate information at positions other than the detection position.

[0066] The controller 9 controls the welding robot 3 according to a predetermined measurement program and welding program. Specifically, the welding robot 3 is moved based on the measurement program, and the coordinates of the detection position in the workpiece W are measured as measurement data by the sensor 7 provided by the welding robot 3. In addition, the welding robot 3 is moved based on the welding program to weld the workpiece W. The measurement program and the welding program are provided by the welding control device 8.

[0067] The camera 10 is used to photograph the workpiece W before welding and determine the shape, size, position, etc. of the workpiece W. The camera 10 is configured to obtain point group data of the surface of the workpiece W as three-dimensional data. As the camera 10, for example, a ToF (Time of F light) camera, a stereo camera, or a LiDAR (Light Detection And Ranging) sensor can be used. The above sensors have different characteristics, so they can be used according to the measurement environment and the workpiece W as the measurement object. In the present embodiment, the camera 10 is arranged above the workpiece W and the locator 2, and is configured to be able to photograph the workpiece W located below. It should be noted that the setting position and shooting direction of the camera 10 are not limited to this, and can be arbitrarily set corresponding to the rotation axis of the workpiece W based on the locator 2.

[0068] The ToF camera that can be used as camera 10 irradiates a laser onto the object to be measured, and uses an imaging element to measure the reflected laser, thereby calculating the distance for each pixel. The measurable distance of a ToF camera is about tens of cm to several meters. A stereo camera uses multiple images captured by multiple (for example, 2) cameras to calculate the distance based on their parallax. The measurable distance of a stereo camera is about tens of cm to several meters. LiDAR calculates the distance by irradiating the surrounding area with laser and measuring the reflected laser. The measurable distance of LiDAR is about tens of cm to tens of meters.

[0069] The moving units 11 and 12 move the welding robot 3 in at least one of a direction parallel to the rotation axis direction of the workpiece W held by the positioner 2 and a direction orthogonal to the rotation axis direction. Specifically, a trolley can be used as the moving unit 11, and a track can be used as the moving unit 12. The moving unit 12 moves along the moving unit 11 parallel to the rotation axis of the positioner 2, thereby moving the welding robot 3 mounted on the moving unit 12 parallel to the axial direction of the workpiece W. In addition, by configuring the moving unit 12 to be movable in a direction orthogonal to the moving unit 11, the welding robot 3 mounted on the moving unit 12 moves in a direction orthogonal to the axial direction of the workpiece W.

[0070] It should be noted that in this embodiment, three three-dimensional coordinate systems are used, namely, the robot coordinate system as the coordinate system of the welding robot 3, the positioner coordinate system as the coordinate system of the positioner 2, and the camera coordinate system as the coordinate system of the camera 10. These coordinate values ​​are established in a convertible manner. In addition, each coordinate system can be defined relatively with respect to any one as a reference, or can be defined in an absolute coordinate system. In the following, when referring to a specific coordinate system for explanation, the coordinate system is specifically shown.

[0071] (Workpiece)

[0072] Figure 2 1 is an external perspective view showing a structural example of a workpiece W as a measurement object of the present embodiment. A camera 10 is arranged above the workpiece W, which can obtain point group data on the surface of the workpiece W. The workpiece W is composed of a column 21 and two partitions 22 arranged on both sides thereof. The column 21 can be a columnar member composed of a square cylinder (such as a square steel pipe) or a cylindrical shape (such as a round steel pipe). The outer peripheral portion of the column 21 is configured to include a flat portion and a curved portion with a certain curvature according to the shape. The curvature of the curved portion is not particularly limited.

[0073] exist Figure 2 In FIG. 1 , L represents the length of the column 21 and H represents the diameter. The partition 22 is formed of a rectangular shape, for example. Figure 2 P0 to P6 shown in the figure are examples of position coordinates extracted from the measurement data. In the workpiece W, the position coordinates to be extracted are not particularly limited. In addition, the shape of the workpiece W is not limited to Figure 2 The structure of the first-level core shown in the figure. For example, the structure of the second-level core can also be composed of two columns and three partitions arranged between them and at both ends. It should be noted that, in the case where the workpiece W has a second-level core structure, the camera 10 can adjust its position according to its shooting range and obtain the point group data of the entire workpiece W by taking multiple shots. In addition, a groove 23 of a predetermined shape is formed at the connection between the column 21 and the partition 22.

[0074] (Welding control device)

[0075] Figure 3 301, a storage unit 302, an IF (Interface) unit 303, a communication unit 304, and a UI (User Interface) unit 305.

[0076] The control unit 301 can be composed of at least one of a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), or an FPGA (Field Programmable Gate Array). In addition, the storage unit 302 is composed of a volatile or non-volatile storage device such as a HDD (Hard Disk Drive), a ROM (Read Only Memory), or a RAM (Random Access Memory). The control unit 301 reads and executes various programs stored in the storage unit 302, thereby realizing various functions described later.

[0077] The IF unit 303 is an interface for connecting to an external device and is responsible for sending and receiving to and from the external device. The IF unit 303 is connected to, for example, the controller 9 and the positioner 2.

[0078] The communication unit 304 is a part for communicating with external devices and various sensors. The communication performed by the communication unit 304 is not limited to wired / wireless, and the communication standard is not limited. The UI unit 305 receives operations from the user or displays measurement results. The UI unit 305 may include, for example, a mouse, a keyboard, etc., which are not shown in the figure, or may be composed of a touch panel display in which a display unit and an operation unit are integrated. The various parts in the welding control device 8 are connected to each other so as to be communicable through an internal bus, etc., which are not shown in the figure.

[0079] [Functional structure]

[0080] Figure 4 An example of the functional configuration of welding control device 8 according to the present embodiment is shown. Figure 4 The various parts shown can be realized by the control unit 301 of the welding control device 8 reading and executing the program stored in the storage unit 302. It should be noted that Figure 4 The structure shown is an example, and one part may be constituted as multiple parts, or multiple parts may be constituted as one part. In addition, when multiple control devices cooperate to perform welding in the welding system 100, according to its structure, Figure 4 The various parts shown can be configured in corresponding control devices.

[0081] The data acquisition unit 401 acquires point group data of the workpiece W as a measurement target via the camera 10. In addition, the data acquisition unit 401 acquires various data measured by using the contact sensing function of the sensor 7 provided at the front end of the welding robot 3. The data mode control unit 402 controls the operation mode in the welding system 100. For example, the mode and parameter control related to the measurement of the workpiece W performed before welding, the mode and parameter control during welding, etc. can be performed.

[0082] The preprocessing unit 403 preprocesses the acquired point group data. The preprocessing here may vary depending on the point group data used, and may include, for example, filtering, outlier removal, clustering, coordinate conversion, etc. The program generating unit 404 modifies the welding program and sensing program of the common content stored in advance based on the measurement results, thereby generating a program corresponding to the workpiece W to be welded.

[0083] The estimation processing unit 405 performs a process of estimating the shape of the workpiece W using the acquired point group data. The details of the estimation process will be described later. The estimation result storage unit 406 stores the shape and position of the workpiece W estimated by the estimation process of the estimation processing unit 405 as an estimation result. The data management unit 407 stores information on the workpiece W specified in advance and data related to the welding operation.

[0084] The sensing program storage unit 408 stores a sensing program for sensing using the sensor 7 provided at the front end of the welding robot 3. The welding program storage unit 409 stores a welding program used when the welding robot 3 is used for welding.

[0085] The robot control unit 410 controls the welding robot 3 via the controller 9 using the welding program and the sensing program to perform various actions. The robot control unit 410 may also control the moving units 11 and 12. The positioner control unit 411 controls the positioner 2 holding the workpiece W using the welding program and the sensing program to perform a rotation action, etc. The camera control unit 412 controls the measurement action based on the camera 10.

[0086] [Measurement example]

[0087] use Figure 5 to Figure 8B An example of measurement of the workpiece W according to the present embodiment will be described. Figure 5 This is the appearance diagram of workpiece W. Figure 5 The origin of the coordinate axes shown is located differently, but its orientation corresponds to the positioner coordinate system in positioner 2. Figure 2 As described above, the workpiece W is composed of the column 21 and the partition plate 22. Figure 5In the example, the region R is a curved surface, and its shape may not be accurately obtained as point group data depending on the shooting direction of the camera 10. Therefore, for example, as shown by the length l, there is a concern that the size of the workpiece W may be detected as shorter than it should be. In the present embodiment, it is configured to be able to perform measurement corresponding to the structure of such a workpiece W.

[0088] Figure 6 FIG. 2 shows a state where the workpiece W is viewed from the side along the X-axis direction. The coordinate system superimposed on the workpiece W is the positioner coordinate system. Figure 1 As shown, the workpiece W is held in the horizontal direction. Here, the z-axis of the positioner coordinate system coincides with the rotation axis of the positioner 2. In addition, the camera 10 captures the workpiece W along the Y-axis direction.

[0089] exist Figure 6 In FIG. 1 , the length L represents the length of the column 21 in the Z-axis direction, and the diameter H represents the radius of the column 21. The point group data Pd is represented by projecting the point group data representing the outer shape of the workpiece W acquired by the camera 10 onto the yz plane. In addition, P2 and P3 represent Figure 2 The connection position between the partition 22 and the column 21 shown in FIG. As shown in P2 and P3, when observed on the yz plane, the connection position between the partition 22 and the column 21 can be captured as a change point of the point group data in which the distribution of the point group data changes in a specified direction. Therefore, the diameter H of the column 21 can be derived based on the value of the y coordinate of the locator coordinate system. In addition, the length L of the column 21 can be derived based on the values ​​of the y coordinate and the z coordinate of the locator coordinate system. Furthermore, based on the values ​​of the y coordinate and the z coordinate of the locator coordinate system, the length of the partition 22 in the Z-axis direction, that is, the plate thickness, can also be derived.

[0090] Fig. 7A An example of point group data when measuring a workpiece W is shown. Fig. 7A In FIG. 1 , the horizontal axis represents the value of the z coordinate in the positioner coordinate system, and the vertical axis represents the value of the y coordinate in the positioner coordinate system. The origin of the z coordinate corresponds to the holding position of the positioner 2 for the workpiece W.

[0091] The solid line 700 is the position coordinate of the surface of the workpiece W estimated from the point group data. In addition, P2 and P3 of the workpiece W are the actual connection positions of the column 21 and the partition plate 22. Fig. 7A As also measured in FIG. 1 , before welding, there is a groove at the connection position between the column 21 and the partition plate 22. The solid line 700 can be obtained by, for example, using a Fused Lasso change point detection method. In the solid line 700, for example, a point that is away from a predetermined threshold value from the minimum value of the Y coordinate can be regarded as a change point. Fig. 7A In the example shown, points that are away from the minimum value of the Y coordinate by a predetermined threshold value are detected at positions P2 and P3.

[0092] Figure 7B This shows an example of point group data when measuring a workpiece with a two-stage core. Figure 7B In the figure, the horizontal axis represents the value of the z coordinate in the positioner coordinate system, and the vertical axis represents the value of the y coordinate in the positioner coordinate system. The origin of the z coordinate corresponds to the holding position of the positioner 2 on the workpiece W. The solid line 800 is the position coordinate of the surface of the workpiece estimated based on the point group data. P1'~P4' represents the actual connection position of the column and the partition. Fig. 7A , Figure 7B As shown, by capturing the change points of the point group data corresponding to the connection positions of the pillars and partitions, that is, the parts where the distribution of the point group data changes, the number of components of the workpiece W, that is, the number of pillars and the number of partitions, can also be derived.

[0093] Here, the handling of the setting error of the positioner 2 for the workpiece W according to the present embodiment is described. Assume that the holding position of the workpiece W by the positioner 2 deviates from the rotation axis of the positioner 2. In this case, Fig. 8A As shown in FIG. 1 , the central axis C of the column 21 is misaligned with the rotation axis (corresponding to the z-axis) of the positioner 2. As a result, the measured value of the diameter of the column 21 is offset. Fig. 8A In the case of the example, a setting error herr is generated relative to the measured value h. At this time, the actual diameter of the column 21 is (h+herr).

[0094] In the present embodiment, such an installation error of the positioner 2 is taken into consideration, and a plurality of measurements are performed by rotating the positioner 2. Then, the installation error is corrected based on the results of the plurality of measurements.

[0095] Figure 8B This is a diagram for explaining the concept of correcting the setting error. Here, the center axis C of the column 21 is offset from the rotation axis (corresponding to the z-axis) of the positioner 2. Pd1 is the point group data obtained by the first measurement. Based on the point group data Pd1, h1 is obtained as the diameter of the column 21, and a value different from the actual value is obtained due to the setting error. In contrast, the workpiece W is rotated 180 degrees along the rotation axis (corresponding to the z-axis) by the positioner 2, and the measurement is performed again. As a result, Pd2 is obtained as the point group data. Based on the point group data Pd2, h2 is obtained as the diameter of the column 21.

[0096] In this embodiment, the setting error is corrected by averaging the values ​​obtained as a result of these multiple measurements. Therefore, the diameter H of the column 21 excluding the influence of the setting error can be calculated by H = (h1 + h2) / 2. It should be noted that other rotation angles can be used considering the direction of the setting error. For example, 90 degrees and 270 degrees can be used as the rotation angle of the positioner 2. In addition, the number of measurements is not limited to two times, and more measurements can be performed considering the measurement accuracy, etc.

[0097] Based on the point group data obtained by the camera 10, the approximate size and installation position of each part constituting the workpiece W can be determined. Based on this result, the welding robot 3 can be brought close to the periphery of the workpiece W. During welding, the position of the front end of the welding torch 5 can be controlled with higher accuracy. Therefore, more precise position detection is performed by contact sensing based on the sensor 7 provided at the front end of the welding torch 5. In other words, based on the point group data obtained by the camera 10, the size and installation position of the workpiece W can be estimated with a certain accuracy and moved to the vicinity thereof, and the starting position of the contact sensing can be adjusted. Therefore, the time required for the contact sensing action performed by the sensor 7 can be reduced.

[0098] Furthermore, after the size and installation position of the workpiece W are estimated with a certain degree of accuracy by the method using the above-mentioned point group data, the contact sensing operation performed by the sensor 7 can accurately measure the area R, groove and other parts, and correct the size and installation position of the workpiece W. Thus, the position for welding the workpiece W can be accurately determined, and more accurate welding automation can be realized.

[0099] [Processing Flow]

[0100] Hereinafter, a welding flow including the workpiece measurement process according to the present embodiment will be described. Fig. 9 1 is a flowchart showing the overall welding process including the workpiece measurement process of this embodiment. Figure 1 The welding control device 8 shown is implemented by controlling various parts of the welding system 100. Here, for simplicity of description, the processing body is collectively described as the welding control device 8. Before starting this processing flow, the workpiece W is held by the positioner 2 and arranged at a position where it can be photographed by the camera 10.

[0101] In step S901, the welding control device 8 sets the measurement mode. The measurement mode here can be based on a mode specified by the user or a pre-defined mode. In the measurement mode, for example, a mode of performing multiple measurements by changing the rotation angle of the positioner 2 as described above and a mode of performing only one measurement can be specified.

[0102] In step S902, the welding control device 8 uses the camera 10 to photograph the workpiece W and obtain point group data. When the workpiece W is smaller than the specified size, the point group data can be obtained through a single photographing action. In addition, when the workpiece W is larger than the specified size, multiple point group data can be obtained through multiple photographing actions and merged. In this process, the welding control device 8 can adjust the shooting range and shooting angle according to the position of the positioner 2 in time during shooting, or it can be specified according to the measurement mode set in step S901.

[0103] In step S903, the welding control device 8 performs preprocessing on the point group data obtained in step S902. Examples of preprocessing include filtering, outlier removal, clustering, and coordinate conversion. It should be noted that the preprocessing in this step only needs to perform required processing according to the structure of the point group data obtained in step S902, and the preprocessing may be omitted.

[0104] The filtering process may be, for example, a known Voxel Grid filter, etc., to resample the point groups included in the point group data at a certain interval, thereby making the point group density per specified volume constant. The outlier removal process may be a process for removing outliers that can reduce the measurement accuracy. The outliers may be determined, for example, based on statistical information such as the average and variance of adjacent point groups, or may be determined based on the number of adjacent point groups within a specified radius. The clustering process may be, for example, the following process: the point groups included in the point group data are divided into a plurality of groups based on distance, etc., and the groups to which the number of point groups belongs is less than a specified threshold are deleted, thereby removing point groups other than the point groups representing the shape of the workpiece W. The coordinate conversion process converts from the camera coordinate system of the camera 10 to a specified coordinate system based on the shooting position and shooting angle of the camera 10. The specified coordinate system may be, for example, the locator coordinate system of the locator 2. The parameters required for the conversion of the coordinate system may be derived through a prior calibration process, etc.

[0105] In step S904, the welding control device 8 uses the point group data processed in step S903 to estimate the size and shape of the workpiece W. The estimation process here may include estimating the installation position of the workpiece W and the number of columns 21 and partitions 22 constituting the workpiece W. In this embodiment, Figure 6 As shown, the length L and diameter H of the column are estimated.

[0106] like Figure 5As shown, the column 21 constituting the workpiece W may have a region R having a certain curvature. In the case where the column 21 is cylindrical (for example, a round steel pipe), the region R becomes larger. Therefore, in this embodiment, in the xz plane of the locator coordinate system, only the point group data near the center of the column 21 is extracted. In this embodiment, the zy plane is a horizontal plane, which is orthogonal to the shooting direction of the camera 10. As the vicinity of the center of the workpiece W here, for example Figure 6 As shown in FIG. 1 , in the case of assuming a positioner coordinate system, the range in the X-axis direction may be -50 mm < x < 50 mm. This range may be changed according to the size and shape of the workpiece W to be measured, the setting of the positioner coordinate system (i.e., the setting position of the workpiece W in the positioner 2), etc. As point group data about this area, the following can be obtained: Fig. 7A Data shown.

[0107] In step S905, the welding control device 8 determines whether the measurement is completed. For example, the determination may be made based on whether the number of measurements specified based on the mode set in step S901 has been performed. Alternatively, an operation from a user may be accepted and the measurement may be determined to be completed based on the operation. If the measurement is completed (Yes in step S905), the processing of the welding control device 8 proceeds to step S907. On the other hand, if the measurement is not completed (No in step S905), the processing of the welding control device 8 proceeds to step S906.

[0108] In step S906, the welding control device 8 performs rotation control of the positioner 2 at a predetermined rotation angle. The rotation angle here can be specified, for example, according to the mode set in step S901. Specifically, when the first rotation angle is set to 0 degrees around the z-axis of the positioner coordinate system, 180 degrees, 90 degrees, 270 degrees, etc. can be used appropriately. Then, the processing of the welding control device 8 returns to step S902 and the processing is repeated.

[0109] In step S907, the welding control device 8 corrects the estimated result and calculates the setting error. Figure 8B It is corrected and calculated as described. It should be noted that this process can be performed when the workpiece W is rotated by the positioner 2 and multiple measurements are performed. Therefore, this process can be omitted when only one measurement is performed. In addition, the processing to be performed can be switched according to the measurement results.

[0110] In step S908, the welding control device 8 generates a contact sensing program based on the estimation result. The contact sensing program is predefined by common contents. Then, the parameters for the workpiece W are adjusted according to the size and installation position of the workpiece W based on the estimation result, thereby generating the contact sensing program.

[0111] In step S909 , welding control device 8 operates welding robot 3 and the like based on the contact sensing program generated in step S908 , and measures the size and position of workpiece W more precisely using sensor 7 provided at the front end of welding robot 3 .

[0112] In step S910, the welding control device 8 generates a welding program based on the size and position of the workpiece W measured in step S909. The welding program is predefined by general content. Then, the welding program is generated by adjusting the parameters for the workpiece W according to the more precise size and installation position of the workpiece W based on the measurement results.

[0113] In step S911 , the welding control device 8 operates the welding robot 3 and the like based on the welding program generated in step S910 to perform welding on the workpiece W. Then, after the welding is completed, this processing flow ends.

[0114] As described above, according to the present embodiment, the measurement time of the measured object can be shortened compared with the past, and the structure of the measured object can be measured with high accuracy. In particular, the number and position of the columns and partitions constituting the workpiece can be easily estimated with a certain degree of accuracy, and the time for operating the welding robot for measurement can be shortened.

[0115] <Other embodiments>

[0116] The present embodiment can also be implemented by providing a program or application for implementing the functions of one or more of the above-mentioned embodiments to a system or device using a network or storage medium, and one or more processors in a computer of the system or device read out and execute the processing of the program.

[0117] In addition, the present embodiment may be implemented by a circuit that implements one or more functions. It should be noted that examples of the circuit that implements one or more functions include ASIC (Application Specific Integrated Circuit) and FPGA (Field Programmable Gate Array).

[0118] As described above, the following matters are disclosed in this specification.

[0119] (1) A workpiece measuring method for measuring a workpiece (e.g., workpiece W) which is composed of a columnar member (e.g., column 21) and a spacer (e.g., spacer 22) and is held by a positioner (e.g., positioner 2), characterized in that:

[0120] The workpiece measuring method comprises:

[0121] an acquisition step of acquiring point group data of the surface of the workpiece held by the locator, which is photographed along a predetermined direction (for example, the Y-axis direction of the locator coordinate system);

[0122] a detection step of determining, in the three-dimensional coordinate system of the locator, a portion where the distribution of the point group data changes, and detecting it as a boundary position (for example, P2, P3) between the columnar member and the partition plate; and

[0123] The derivation step derives the number of the columnar members and the spacers constituting the workpiece based on the boundary position detected in the detection step.

[0124] According to this structure, the measurement time of the measured object can be shortened compared with the past, and the structure of the measured object can be measured with high accuracy. In particular, the number and position of the columns and partitions constituting the workpiece can be easily estimated with a certain degree of accuracy, and the time required to operate the welding robot for measurement can be shortened.

[0125] (2) The workpiece measuring method according to (1) is characterized in that, in the detection process, the point group data is projected onto a plane (yz plane) represented by a first axis corresponding to the specified direction (for example, the y-axis of the locator coordinate system) and a second axis orthogonal to the first axis (for example, the z-axis of the locator coordinate system) and parallel to the specified direction, and the change point of the point group data is detected as the boundary position between the columnar member and the partition.

[0126] According to this structure, the measurement time of the measurement object can be shortened compared with the conventional method, and the structure of the measurement object can be measured with high accuracy. In particular, the workpiece can be measured based on the holding position of the workpiece by the positioner.

[0127] (3) The workpiece measuring method according to (2), further comprising a calculation step of calculating a size and a position of the workpiece based on the boundary position detected in the detection step.

[0128] According to this configuration, the size and position of the workpiece can be determined with a certain accuracy before the welding robot is operated for measurement, and the start position of the measurement using the welding robot can be adjusted based on the result. As a result, the measurement time by the sensor provided in the welding robot can be shortened.

[0129] (4) The workpiece measuring method according to (3), wherein in the calculation step, at least one of a diameter and a length of a columnar member constituting the workpiece and a plate thickness of the separator is calculated.

[0130] According to this configuration, the dimensions of the pillars and partitions constituting the workpiece can be measured before the welding robot is operated to perform measurement.

[0131] (5) The workpiece measuring method according to (3), wherein in the acquisition step, the workpiece is rotated by the positioner at a predetermined rotation angle about the second axis to acquire a plurality of point group data.

[0132] In the calculation step, the size and position of the workpiece are calculated based on the plurality of point group data.

[0133] According to this configuration, it is possible to perform higher-precision measurement by taking into account the installation error of the workpiece with respect to the positioner.

[0134] (6) A workpiece measuring method according to (2), wherein, in the detection step, the boundary position is detected using point group data of a range specified from the center in the direction of the third axis, among point group data projected onto a plane (e.g., an xz plane) represented by the second axis and a third axis orthogonal to the first axis and the second axis (e.g., the x-axis of the locator coordinate system) and orthogonal to the specified direction.

[0135] According to this configuration, it is possible to remove point cloud data of a region where the measurement accuracy is reduced due to the structure of the sensor, thereby deriving the structure of the workpiece with higher accuracy.

[0136] (7) The workpiece measuring method according to (3), further comprising a calibration step of calibrating at least one of the size and the position of the workpiece calculated in the calculation step by sensing.

[0137] According to this configuration, in the welding system, correction can be performed by more accurate sensing based on roughly obtained measurement results.

[0138] (8) A welding system (e.g., welding system 100) comprising:

[0139] a welding robot (e.g., welding robot 3) having a welding torch (e.g., welding torch 5);

[0140] A welding control device (e.g., welding control device 8), which controls the welding robot;

[0141] a positioner (eg, positioner 2 ) that holds a workpiece (eg, workpiece W) composed of a columnar member (eg, column 21 ) and a partition (eg, partition 22 ); and

[0142] A sensor (e.g., camera 10) that captures the workpiece from a predetermined direction to obtain point group data.

[0143] It is characterized in that

[0144] The welding control device comprises:

[0145] an acquisition unit (e.g., the control unit 301, the IF unit 303, the data acquisition unit 401) that acquires point group data of the surface of the workpiece held by the positioner, which is captured by the sensor from the predetermined direction;

[0146] a detection unit (e.g., the control unit 301, the estimation processing unit 405) that determines, in the three-dimensional coordinate system of the locator, a portion where the distribution of the point group data changes, and detects it as a boundary position between the columnar member and the partition; and

[0147] A calculation unit (for example, the control unit 301 or the estimation processing unit 405 ) calculates the size and position of the workpiece based on the boundary position detected by the detection unit.

[0148] According to this configuration, the measurement time of the measurement object can be shortened compared with the related art, and the structure of the measurement object can be measured with high accuracy.

[0149] (9) The welding system according to (8) is characterized in that the welding torch has a second sensor (e.g., sensor 7), and the welding control device has a correction unit (e.g., control unit 301, program generation unit 404), and the correction unit corrects at least one of the size and position of the workpiece calculated by the calculation unit based on the sensing of the second sensor.

[0150] According to this configuration, the size and position of the workpiece can be determined with a certain accuracy before the welding robot is operated for measurement, and the start position of the measurement using the welding robot can be adjusted based on the result. As a result, the measurement time by the sensor provided in the welding robot can be shortened.

Claims

1. A workpiece measuring method for measuring a workpiece, wherein the workpiece is composed of a columnar member and a partition plate and is held by a positioner, wherein: The workpiece measuring method comprises: an acquisition step of acquiring point group data of the surface of the workpiece held by the locator and photographed from a predetermined direction; a detection step of determining, in the three-dimensional coordinate system of the locator, a portion where the distribution of the point group data changes, and detecting the portion as a boundary position between the columnar member and the partition plate; and The derivation step derives the number of the columnar members and the spacers constituting the workpiece based on the boundary position detected in the detection step.

2. The workpiece measuring method according to claim 1, characterized in that: In the detection step, the point group data is projected onto a plane represented by a first axis corresponding to the specified direction and a second axis orthogonal to the first axis and parallel to the specified direction, and a change point of the point group data is detected as a boundary position between the columnar member and the partition.

3. The workpiece measuring method according to claim 2, characterized in that: The workpiece measuring method further includes a calculation step of calculating a size and a position of the workpiece based on the boundary position detected in the detection step.

4. The workpiece measuring method according to claim 3, characterized in that: In the calculation step, at least one of a diameter and a length of a columnar member constituting the workpiece and a plate thickness of the separator is calculated.

5. The workpiece measuring method according to claim 3, characterized in that: In the acquisition step, the workpiece is rotated by the positioner at a predetermined rotation angle about the second axis to acquire a plurality of point group data. In the calculation step, the size and position of the workpiece are calculated based on the plurality of point group data.

6. The workpiece measuring method according to claim 2, characterized in that: In the detection process, the boundary position is detected using point group data of a specified range starting from the center in the third axis direction, among point group data projected onto a plane represented by the second axis and a third axis orthogonal to the first axis and the second axis and orthogonal to the specified direction.

7. The workpiece measuring method according to claim 3, characterized in that: The workpiece measuring method includes a calibration step of calibrating at least one of a size and a position of the workpiece calculated in the calculation step by sensing.

8. A welding system comprising: A welding robot having a welding torch; A welding control device, which controls the welding robot; a positioner that holds a workpiece composed of a columnar member and a partition plate; and A sensor that captures the workpiece from a predetermined direction to obtain point group data. It is characterized in that The welding control device comprises: an acquisition unit that acquires point group data of the surface of the workpiece held by the positioner, which is photographed by the sensor from the predetermined direction; a detection unit that determines, in the three-dimensional coordinate system of the locator, a portion where the distribution of the point group data changes, and detects the portion as a boundary position between the columnar member and the partition; as well as A calculation unit calculates the size and position of the workpiece based on the boundary position detected by the detection unit.

9. The welding system according to claim 8, characterized in that The welding torch has a second sensor, The welding control device includes a correction unit that corrects at least one of a size and a position of the workpiece calculated by the calculation unit through sensing by the second sensor.

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