JP2006072673A - Positioner setting method for welding robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioner setting method for a welding robot that can shortly, safely, and accurately position a positioner for supporting a workpiece. <P>SOLUTION: The positioner setting method for a welding robot has: a step (Step 1) of reading into a computer mechanism information about a positioner and a three-dimensional model of a workpiece; a step (Step 2 to Step 7) of specifying either a weld surface or line of at least either member to be welded of the model; a step (Step 8) of computing a reference line defining the inclination of a weld zone from the specified weld surface or line information; a step (Step 9) of setting α and β as target angles of the workpiece, where α and β are angles of inclination of the reference line against the vertical in two orthogonal directions; and a step (Step 10 to 20) of moving the workpiece model in a range allowable from the positioner mechanism to compute one or a combination of positioner positions bringing α and β into target angle ranges. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a positioner setting method for a welding robot capable of safely and accurately positioning a positioner that supports the workpiece when performing automatic welding on the workpiece using a welding robot.

  A positioner for supporting a workpiece in robot welding generally has a maximum of two orthogonal axes, and the optimum welding angle is determined by adjusting the inclination angles of the two axes.

  11 and 12 are cross-sectional views showing typical weld plate surfaces in horizontal fillet welding and downward fillet welding, respectively. 11 and 12, the base material surface 55 and the upright plate surface 56 intersect each other at a right angle. In such a case, the optimum welding posture can be easily determined.

  However, the weld plate surface in the actual workpiece is not necessarily parallel or orthogonal to the axis of the positioner, and the optimum weld plate surface for welding is not always present, so an approximate value may be substituted. There may be a plurality of optimum values or approximate values. Therefore, the positioning operation of the positioner using the conventional positioning method for visually adjusting the tilt axis and the rotation axis of the positioner has been extremely difficult.

  13 and 14 are explanatory views showing an example of an actual work, FIG. 13 is a perspective view of the work, and FIG. 14 is a front view of FIG. In FIG. 13, this work has a plurality of horizontal surfaces, vertical surfaces, and inclined surfaces. In order to weld a line that intersects each surface, the line that intersects each surface is selected as a valley of the weld line, and the tilt angle of the workpiece that can obtain the optimum welding posture in robot welding, that is, the positioner shaft that supports the workpiece It is necessary to determine the inclination angle, and the determination method is extremely complicated. In FIG. 13, the first axis and the second axis of the positioner are not shown.

  Further, in the conventional positioner positioning method, there are cases where there are a plurality of target angles due to the function of the positioner, or there are cases where the target accurate angle cannot be found. In such a case, the optimum angle is searched and determined. Therefore, there is a problem that the operator has to rely on the experience and feeling of the operator. Furthermore, when the weld line is an arc or free curve on a curved surface, it takes a long time to search for the optimum positioner angle, and it is difficult to evaluate whether the obtained search results are optimal. .

  In addition, when performing actual machine teaching using an actual robot, the operator approaches the work mounted on the positioner, installs an inclinometer at several locations, and guides the positioner to obtain the plate surface angle. Thus, there are various problems in safety, efficiency and accuracy.

  For example, Japanese Patent Application Laid-Open No. 11-347733 is known as a conventional technique relating to such a positioner positioning method or a welding robot automatic teaching method. The purpose of this conventional technique is to automatically calculate the positioner angle so that the welding position of the robot is as downward as possible when creating a welding robot system program that positions the workpiece using the positioner. It was made.

  FIG. 17 is an explanatory diagram for obtaining a release vector from the normal vector of each surface of the welded portion in the above-described prior art. In FIG. 17, a vector VA that divides the angle formed by two normals into two equal parts is obtained from the normal vector V1 of the surface SA and the normal vector V2 of the surface SB at the welding start point PA of the weld line 58. Similarly, a release vector VB (not shown) at the welding end point PB is obtained. Such work is performed on the weld lines of all the joints, and this release vector or angle from one side is designated and used as a welding posture. That is, in the above prior art, after obtaining a weld line from the workpiece shape and welding attribute data input in the designed three-dimensional CAD, the release direction of the torch at the weld line is obtained, and the positioner is set so that the torch is directed downward. (Patent Document 1, paragraph 0030, FIG. 3).

Japanese Patent Laid-Open No. 11-347733

  However, the above prior art uses a vector defining one direction, and has the following problems.

  That is, since the release vector for determining the positioner angle disclosed in the above prior art is a two-dimensional one that is geometrically determined by the design CAD, it is not possible to set a subtle inclination. The prior art has a problem that it is difficult to maintain high welding quality. Also, in actual welding sites, the welding posture is not limited to the downward direction, it is necessary to cope with various welding postures in a short time, and the workpiece may be slightly inclined as necessary to improve the welding quality. It is necessary to accurately adjust this inclination angle, and when the welding line is an arc or a free curve placed on the curved surface, it is necessary to determine the angle of the plate surface on the curved surface, and It is necessary to satisfy various requirements such as the ability to determine an optimal angle so that the robot can smoothly move the point. However, the above-described prior art has a problem that the above-described requirement cannot be satisfied.

  The present invention has been made in view of such problems, and in order to determine a welding line when performing automatic welding using a welding robot, positioning of a positioner that supports a workpiece can be safely and accurately performed in a short time. It is an object of the present invention to provide a position setting method for a welding robot that can be performed and thereby can stabilize welding quality to a high degree.

  In the welding robot positioner setting method according to the first invention of the present application, a workpiece to be welded is set on the positioner of the welding robot, and the positioner is positioned so that the workpiece has a desired arrangement with respect to the welding torch. In the method for setting the positioner of the welding robot, a step of reading a three-dimensional model of the workpiece together with mechanism information of the positioner to a computer, and a step of instructing at least one welding surface or line of a welding target member of the model And a step of calculating a reference line for determining the inclination of the welded part from the instructed welding surface or line information, and α and β are angles at which the reference line is inclined from the vertical direction in two directions orthogonal to each other. The steps of setting α and β as target angles of the workpiece, and the work within a range allowed by the positioner mechanism. Move the model, the α and the β is characterized by having a step of determining by calculation the positioner positions of one or more combinations becomes a target angle range, the.

  In the welding robot positioner setting method according to the second aspect of the present invention, a workpiece to be welded is installed on the positioner of the welding robot, and the positioner is positioned so that the workpiece is in a desired arrangement with respect to the welding torch. In the method for setting the positioner of the welding robot, a step of reading a three-dimensional model of the workpiece together with mechanism information of the positioner to a computer, and a step of instructing at least one welding surface or line of a welding target member of the model And a step of calculating a reference line for determining the inclination of the welded part from the instructed welded surface or line information, and the reference line is in a vertical direction when the reference line is projected onto a surface orthogonal to the surface including the welded part Is α, and when the reference line is projected onto a surface including the welded part, the reference line is not perpendicular to the vertical direction. The step of setting these angles α and β as target angles of the workpiece, where β is an angle, and moving the workpiece model within a range allowed by the positioner mechanism, so that α and β are within the target angle range 1 Or calculating a plurality of combinations of positioner positions by calculation.

  In the welding robot positioner setting method according to the present invention, the step of designating the welding surface is performed by clicking the positions of three points on the welding surface on the display screen of the computer when the welding surface is a plane. The three-dimensional coordinates (x11, y11, z11), (x12, y12, z12), (x13, y13, z13) of the three points on the welding surface or one point of the welding surface on the display screen It is preferable that the equation of the surface is obtained from the surface information of CAD data input in advance by clicking.

  In the welding robot positioner setting method according to the present invention, the reference line is different depending on a welding posture.

  Furthermore, in the positioner setting method for a welding robot according to the present invention, the reference line is a line obtained by equally dividing each normal between two welding surfaces when the welding posture is downward welding. And

  Further, in the positioner setting method of the welding robot according to the present invention, the reference line is a line perpendicular to the welding surface on the base metal side or a line perpendicular to the welding surface on the vertical plate side when the welding posture is horizontal. It is characterized by being.

  Furthermore, in the positioner setting method for a welding robot according to the present invention, when the welding surface is an arc surface, the reference line is a line perpendicular to the tangent line at the welding point and passing through the center of the arc. It is characterized by.

  In the positioner setting method for a welding robot according to the present invention, when the rotation angle around the vertical vertical line of gravity of the workpiece model is γ, the positioner positions of one or a plurality of combinations in which α and β are in a target angle range Preferably, the step of calculating by calculating the combination so that, in addition to α and β, the γ also falls within the target angle range.

  The welding robot positioner setting method according to the present invention preferably includes a step of guiding the robot on the computer to the welding surface or the welding line based on the positioner position obtained by the calculation.

  Moreover, in the positioner setting method of the welding robot according to the present invention, it is preferable that when the positioner has a plurality of rotation axes, a step of calculating a positioner position while fixing one rotation axis is preferable.

  The welding robot positioner setting method according to the present invention may further include a step of temporarily storing a plurality of combinations of positioner positions obtained by the calculation in a computer table and displaying them on a screen based on a display command. preferable.

  According to the positioner setting method for the welding robot according to the first invention of the present application, the positioning of the positioner that realizes the welding posture in robot welding is performed using a computer. The positioner positioning work that has been performed can be performed safely and accurately in a short time. In addition, it is easy to operate and does not require skill, and an optimum one can be obtained from a plurality of candidates searched by the computer.

  According to the positioner setting method for the welding robot according to the second invention of the present application, as in the case of the above-described invention, the positioning operation of the positioner, which has been conventionally performed at the welding site with a long time and danger, is performed safely and accurately in a short time. be able to. In addition, it is easy to operate and does not require skill, and an optimum one can be obtained from a plurality of candidates searched by the computer.

  According to the positioner setting method for a welding robot according to claim 3 of the present application, the reference plane on the workpiece is specified by specifying coordinates (x, y, z) of arbitrary three points on the plane, or input in advance. Since the surface equation is obtained from the surface information of the CAD data, the plane of the workpiece can be specified accurately and easily. In addition, this makes it possible to perform the positioning operation of the positioner more quickly and accurately. That is, by designating three-dimensional coordinates of three points, surface information is obtained by creating a surface equation from the information of these three points. It is also possible to specify a surface on the work model and obtain surface information from coordinate values included in advance in the work model.

  According to the positioner setting method of the welding robot according to claim 4 of the present application, the reference line is made different depending on the welding posture, so that the welding posture is not limited to the downward welding but the horizontal fillet welding, the lateral welding, the vertical welding, etc. Can be accurately determined in a short time. Further, for the purpose of improving the welding quality, it is possible to carry out accurately and in a short time even when a slight inclination angle is given to the horizontal plane as necessary.

  Further, according to the position setting method for the welding robot according to claim 5 of the present application, the reference line when the welding posture is downward welding is a line obtained by dividing the normal between the two welding surfaces into two equal parts. Therefore, positioning of the positioner in downward welding can be performed accurately in a short time.

  According to the position setting method of the welding robot according to claim 6 of the present application, the reference line when the welding posture is horizontal is perpendicular to the welding surface on the base metal side or the welding surface on the vertical plate side. Since this is a straight line, positioning of the positioner in horizontal fillet welding can be performed accurately in a short time.

  According to the positioner setting method for a welding robot according to claim 7 of the present application, the reference line when the welding surface is an arc surface is a line perpendicular to the tangent line at the welding point and passing through the center of the arc. The positioning of the positioner when the welding surface is an arc can be performed accurately.

  According to the positioner setting method of the welding robot according to claim 8 of the present application, when the rotation angle around the vertical line of the workpiece model is γ, one or a plurality of combinations in which α and β are in a target angle range. In the step of calculating the positioner position by calculation, the combination is calculated so that in addition to α and β, the γ is also within the target angle range. This can be done specifically.

  According to the welding robot positioner setting method according to claim 9 of the present application, since the robot on the computer is guided to the welding surface or the welding line based on the positioner position obtained by the calculation, It is possible to grasp the positional relationship between the welding robot and the work model.

  According to the positioner setting method of the welding robot according to claim 10 of the present application, when the positioner has a plurality of rotation axes, the positioner position is calculated by fixing one rotation axis. Therefore, the positioner position can be specifically determined even when the solution of the positioner rotation axis to be obtained is infinite.

  Furthermore, according to the positioner setting method for the welding robot according to claim 11 of the present application, the positioner positions of the plurality of combinations obtained by the calculation are temporarily stored in the table of the computer and displayed on the screen based on the display command. Since the process is included, the optimum positioner angle can be selected again after the search is completed.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram of a positioner setting device applied to the welding robot positioner setting method according to the present embodiment. In the present embodiment, a predetermined quadrangle is provided by cutting out one corner of a planar quadrangular plate 33 of the work model shown in FIG. The inclination angle of the positioner shaft is searched when the joining line that is the outer periphery of the joining surface with the plate-like body 34 is used as the welding line. Although it is not easy to search for the optimum positioner angle in such a work model, the two-axis condition of the positioner that enables automatic welding by the welding robot with the joint line in this work model being horizontal and facing the welding torch is obtained. . Hereinafter, the search for the tilt angle of the positioner shaft may be referred to as calculation of the positioner position.

  In FIG. 1, this apparatus includes a search condition setting unit 1 that sets a search condition related to a positioner posture, a reference plane setting unit 2 that sets a reference plane or a reference line of a work supported by the positioner, and a search condition setting unit 1. The work condition calculation preparing unit 3 for aggregating the search conditions set in step 1, the reference plane or reference line data set by the reference plane setting unit 2 and the data 7 related to the work model of FIG. Referring to the display unit 4 for displaying the posture of the work model, the search range setting unit 5 for setting the search range, and the search range data 8 set by the search range setting unit 5, an appropriate inclination of the positioner shaft It is mainly composed of a search for performing an angle (hereinafter also referred to as a positioner value) search and ranking and a ranking unit 6. Note that the operator selects an optimum positioner value, that is, an optimum inclination angle of the positioner, from the appropriate positioner value candidate group 9 ranked by the search and ranking unit 6.

  After the optimum inclination angle is selected by the operator, the two axes of the positioner can be moved to the selected inclination angle on the screen according to the setting conditions, and the welding robot can be moved according to the setting conditions.

  Examples of the search condition data set by the search condition setting unit 1 include inclination angles α and β and a rotation angle γ with respect to a vertical line of a workpiece forming a weld line.

  FIG. 2A to FIG. 2C are explanatory views showing the inclination angle α of the workpiece forming the weld line. The workpiece inclination angle α varies depending on the welding posture or the shape of the weld surface. FIG. 2 (a) is an explanatory diagram showing the inclination angle α in the downward welding, that is, downward fillet welding, and FIG. 2 (b) is the case where the welding attitude is horizontal and the weld surface shape is flat, ie, horizontal. FIG. 2C is an explanatory view showing the inclination angle α when the welding posture is horizontal and the weld surface shape is an arc.

  In FIG. 2A, when the welding posture is downward, a line 14 that bisects the normals 12a and 13a of the two welding surfaces 12 and 13 serves as a reference line, and the bisector 14 and a vertical line. 11 is an inclination angle α. In FIG. 2B, when the welding posture is horizontal, a line 15 perpendicular to the base metal side welding surface 12 is a reference line, and a line 15 perpendicular to the base metal side welding surface 12 is a vertical line. An angle formed by 11 is defined as an inclination angle α. 2C, when the welding posture is horizontal and the weld surface shape is an arc, the angle formed by the arc surface 16 and the vertical line 11, that is, a line perpendicular to the tangent line at the welding point 16a and the center of the arc. The angle formed by the line 16b passing through the vertical line 11 can be defined as an inclination angle α.

  FIGS. 3A and 3B are explanatory views showing the inclination angle β of the workpiece forming the weld line. The workpiece inclination angle β also varies depending on the welding posture and the weld surface shape. FIG. 3A is an explanatory diagram showing the workpiece inclination angle β in fillet welding, and FIG. 3B shows the workpiece inclination angle β when the welding posture is horizontal and the weld surface shape is an arc. It is explanatory drawing.

  In FIG. 3A, an angle formed by a line 19 perpendicular to the welding line 24 where the base material surface 17 and the standing plate surface 18 intersect with the vertical line 11 is defined as β. As shown in FIG. 3B, a line 22 perpendicular to the tangent line at the welding point 21 of the arc 20 when the welding posture is horizontal and the weld surface shape is an arc, and passes through the center of the arc. An angle formed with the vertical line 11 can be defined as β. 2 and 3, only the plane can be set when the welding posture is horizontal.

  FIG. 4 is an explanatory diagram showing the rotation angle γ of the workpiece. In FIG. 4, the rotation angle of the workpiece 23 with respect to the Z axis when the vertical line 11 is the Z axis is defined as the rotation angle γ of the workpiece.

  In the search condition setting unit 1, only the tilt angles α and β or the tilt angles α and β and the rotation angle γ are input and set as search conditions. When α and β are input as search conditions, the inclination angle of the positioner rotation axis in the positioner posture where α and β are close to the target value is searched. The target values of α and β are normally set to 0 degrees. However, for the purpose of improving the quality of welding, the inclination angle β may be set to 5 degrees, for example. In addition, when performing welding with unequal side leg lengths, α is inclined. The input of only the tilt angles α and β is used when examining the positioner posture in various cases.

  On the other hand, when the tilt angles α and β and the rotation angle γ are input, the tilt angle of the positioner rotation shaft in the positioner posture in which α, β, and γ are close to the target values is retrieved. The inclination angles α and β and the rotation angle γ are input as, for example, left and right or front and rear angles of the reference coordinates obtained from the reference plane or reference line, and the rotation angle of the workpiece with respect to the vertical direction. The rotation angle γ is input when the rotation angle of the workpiece that the robot can easily approach is known in advance.

  The search condition setting unit 1 can be set to search for the positioner shaft angle θ1 or θ2 when the first axis or the second axis of the positioner is fixed. When the first axis is selected as the fixed axis, the optimum positioner posture in a state where the first axis of the positioner is fixed is searched. On the other hand, when the second axis is selected as the fixed axis, the optimum positioner posture in a state where the second axis of the positioner is fixed is retrieved. In this case, the operator inputs the angle of the positioner shaft fixed to the personal computer. For example, when the first axis is selected as the fixed axis, the angle θ1 with respect to the vertical line of the first axis is input, and when the second axis is selected as the fixed axis, the inclination angle θ2 with respect to the horizontal plane of the second axis is input. When the fixed axis is not set, the positioner posture in a state where the positioner axis is not fixed, that is, the inclination angles θ1 and θ2 of the first axis and the second axis are searched.

  The search condition setting unit 1 can set whether or not to guide the robot based on the search result. When the setting for guiding the robot is made, the welding robot is guided to the reference position on the personal computer screen with respect to the plate surface or welding line displayed on the screen after the search is completed. The robot is guided with priority on slider guidance, for example. When the operating range limit of the slider is reached, it is supplemented by robot guidance, for example. Note that the posture of the wrist of the robot is determined by, for example, the complement mode. That is, when the wrist mode is held, it is determined depending on, for example, whether the posture of the immediately preceding step is held or whether the wrist angle of the immediately preceding step is held. Further, it is possible to select to fix the positioner at the optimum position based on the search result.

  Further, the search condition setting unit 1 can input and set the maximum number of positioner posture searches, for example, 1 to 99. However, for example, if the search result is 30 ° or more away from the target values of α and β, it can be excluded from candidates. Therefore, the number of candidates may be less than the maximum search value. The search condition setting unit 1 further sets a welding posture, for example, whether it is downward welding or horizontal welding.

  Next, in the reference plane setting unit 2 that sets the reference plane or the reference line, for example, in the case of fillet welding, the base plane and the standing plane are instructed to recognize the reference plane. Specifically, the coordinate data of the three points on the base material surface and the standing plate surface are selected by point sequence selection, for example, point a (x1, y1, z1), point b (x2, y2, z2), point c (x3), respectively. , Y3, z3), the base material surface and the standing plate surface are specified, and a line intersecting these two surfaces is selected as a valley of the weld line. In the case of an arc, three vertices of the work model to be a weld line are designated.

  At this time, the selection of the coordinates of the three points is performed, for example, by clicking the three points on the screen with the mouse. Further, when inputting the three points constituting the standing plate surface, it is also possible to specify that the direction connecting the first point and the second point is the welding direction. Furthermore, the point selection mode can be changed to the surface selection mode.

  The reference plane setting unit 2 sets a reference line (vertical line) that becomes the center of rotation when the rotation angle γ of the workpiece is obtained. FIG. 5 is an explanatory diagram showing a reference line for obtaining the rotation angle γ of the workpiece, FIG. 5 (a) is a diagram showing a reference line in the case of horizontal overlay welding, and FIG. 5 (b) is a horizontal fillet welding. FIG. 5 (c) is an explanatory diagram showing a reference line for downward fillet welding, and FIG. 5 (d) is a case where the welding posture is horizontal and the welding surface shape is an arc. It is explanatory drawing which shows a reference line.

  5A, in the case of horizontal build-up welding, the line is perpendicular to the designated surface (weld surface) 41 and crosses the weld surface 41 at a point 43 at one corner of the weld surface 41, for example. The line 42 to be used is set as a reference line for obtaining the rotation angle γ. Therefore, the rotation angle of the work rotated about the reference line 42 as the rotation axis becomes the rotation angle γ. The reference line for defining the angles α and β may be a line perpendicular to the surface 41, but when defining the rotation angle γ, for example, a line that passes through the point 43 among the lines perpendicular to the surface 41 is used. Must be defined as a book line.

  In the case of horizontal fillet welding, as shown in FIG. 5 (b), since there is a standing plate 44 on the indicated welding surface 54 on the base material side, for example, this standing plate 44 and the welding surface on the base material side are provided. A line 46 perpendicular to the base metal side weld surface 54 at the end point 47 of the weld line 45 to the base line 54 is set as a reference line for obtaining the rotation angle γ. Therefore, the rotation angle of the workpiece rotated about the reference line 46 as the rotation axis is the rotation angle γ.

  In the case of downward fillet welding, as shown in FIG. 5C, for example, the normal lines 36a of the two welding surfaces 36 and 37 at the end points 49 of the welding line 48 where the welding surfaces 36 and 37 contact each other. , 37a is set as a reference line for obtaining the rotation angle γ. Accordingly, the rotation angle of the work rotated about the reference line 38 as the rotation axis becomes the rotation angle γ.

  Further, when the welding surface is an arc, as shown in FIG. 5D, for example, a rotation angle γ is obtained for a line 53 that is perpendicular to the tangent line 52 at the welding point 51 and passes through the center O of the arc. Set as the reference line. Therefore, the rotation angle of the workpiece rotated around the reference line 53 becomes the rotation angle γ.

  In addition, when the surface to be the reference surface of the workpiece is an arc surface, each arc surface can be approximated to a plane by subdividing the arc surface, and can be assumed to be a plane. Coordinate data can also be specified in the same manner as the setting of the base material surface or the standing plate surface.

  In the workpiece posture calculation preparation unit 3, the conditions set by the search condition setting unit 1, the reference plane data set by the reference plane setting unit 2, and the workpiece model data 7 shown in FIG. .

  The posture display unit 4 displays the workpiece posture and the vertical direction, and the search and ranking unit 6 searches for a specific appropriate positioner value, that is, the search for the tilt angle of the rotation axis of the positioner that supports the workpiece and the rank of the search results. The attachment is done. At this time, the search range data 8 of the positioner value set by the search range setting unit 5 is referred to. As an example of setting the search range, a case where the rotation angle of the positioner is limited to 180 degrees, for example, can be considered. This is because the rotation shaft of the positioner cannot always rotate 360 degrees, and the rotation angle is limited based on the workpiece shape and the like.

  The search result is displayed on the computer screen as a group of appropriate positioner value candidates, and the optimum positioner value is selected by the operator.

  Hereinafter, a positioner setting method as an operation of the positioner setting device applied to the present embodiment having such a configuration will be described. FIG. 7 is a flowchart of the positioner setting method for the welding robot according to the present embodiment. In FIG. 7, a trapezoidal portion indicates input by an operator, a rectangular portion indicates processing by a computer, and a parallelogram portion indicates data.

  Before starting the positioning work of the positioner, the operator first causes the computer (hereinafter referred to as a personal computer) in which a CAD system is stored to read the work model together with the model of the 2-axis positioner (step 1). FIG. 6 is an explanatory diagram showing the relationship between the work model 30 captured on the computer and the two axes of the positioner that supports it. In FIG. 6, this positioner has two axes of a first axis 31 and a second axis 32, and the welding line of the work model 30 is a plane that is in contact with a flat rectangular plate 33 and one surface of the plate 33. It is the outer periphery of the joint surface with the plate-like body 34 provided with a predetermined radius by cutting out one corner of the triangle, and consists of a straight line portion and a curved portion. The straight portions of the weld lines between the plate-like bodies 33 and 34 are inclined with respect to the first shaft 31 and the second shaft 32, and the first shaft 31 and the second shaft where the straight portions of the weld lines become horizontal thereafter. 32 inclination angles (θ1, θ2) are obtained.

  After the work model 30 has been read into the personal computer, the operator sets search conditions. That is, it is selected whether the welding posture on the weld plate surface is “downward” or “horizontal”. FIG. 8 is a diagram showing a personal computer screen when setting a search condition. The operator selects, for example, the welding posture “horizontal” in the uppermost welding posture setting unit in FIG. 8 (step 2).

  At this time, it is determined whether or not “downward” is selected as the welding posture by the personal computer (step 3). If “downward” is not selected as in the present embodiment, the shape of the welding surface is “ It asks if it is a “plane” or “arc”. Accordingly, the operator selects that the welding surface (surface B) is “planar” on the screen shown in FIG. 8 (step 4).

  At this time, it is determined whether or not “plane” is selected as the welding surface by the personal computer (step 5). In the present embodiment, since “plane” is selected, the process proceeds to step 7. In Step 7, since the welding posture “horizontal” is set in Step 2 in this embodiment, the operator needs to select and specify the surface B of the work model 30 as the base material surface on the screen (Step 7). ).

  FIG. 9 is a diagram showing a personal computer screen for setting the number of point sequences in the point sequence selection. The operator inputs, for example, the number of point sequences 3 on the personal computer screen of FIG. 9 and clicks, for example, three points on the surface B of the work 30 on the screen to thereby generate points a (x1, y1, z1) and b (x2). , Y2, z2) and the point c (x3, y3, z3) are input to specify the surface B. At this time, by clicking one point on the surface B, the surface equation can be obtained from the surface information of CAD data inputted in advance, and the surface B can be specified by this.

  When the surface B is specified, the coordinates of a line perpendicular to the base material surface in the surface B are automatically determined based on the surface information of the surface B according to a program input in advance.

  In Step 2, when the welding posture is “downward”, it is necessary to select the base material surface and the standing plate surface on the screen (Step 7). The reference plane is selected by designating the coordinates of three points as described above.

  On the other hand, if “plane” is not selected in step 4, the personal computer asks for the data of the arc that is the welding surface. Accordingly, for example, the operator designates the three-point coordinate data of each virtual plane constituting the arcuate surface segmented as described above (step 6).

  After step 7 is completed, the personal computer sets surface B as a reference surface to be used as a reference for welding, displays the vertical direction, and the angle of inclination α, β and rotation angle of the current welded plate surface between surface B and surface A γ is displayed (step 8).

  Here, as described above, the inclination angle α of the welding surface varies depending on the welding posture, but the welding between the surface B and the surface A in the workpiece model 30 is regarded as horizontal fillet welding, and the surface B as the base material surface is obtained. An angle formed by a vertical line (normal line) and a vertical line is used as the inclination angle α.

  On the other hand, the inclination angle β of the welding surface also varies depending on the welding posture, but since the welding between the surface B and the surface A in the workpiece model 30 in FIG. 6 is fillet welding, an angle formed by a line perpendicular to the welding line becomes a vertical line. Is used as the inclination angle β.

  As the rotation angle γ of the welding surface, the rotation angle on the horizontal plane with respect to the vertical line at one point on the intersection line between the surface B and the surface A of the workpiece model 30 is used.

  After the inclination angles α and β and the rotation angle γ of the surface B and the surface A in the current work model 30 are displayed on the personal computer screen (step 8), the operator is based on the search condition setting screen of FIG. The set values α, β, and γ of the tilt or rotation angle are all set and changed to, for example, 0.00 degrees (step 9).

  When the tilt or rotation angles α, β, γ are changed, the personal computer changes the posture of the work model 30 on the screen in accordance with the changed tilt angle (step 10).

  Next, the operator uses all of the inclination or rotation angles α, β, γ of the welding surface as search conditions for the positioner angle while referring to the condition setting screen of FIG. 8, or uses only the inclination angles α, β. Decide what to do. When α, β, and γ are selected, a positioner posture in which α, β, and γ are close to target values is searched. On the other hand, when α and β are selected, a positioner posture in which only α and β are close to the target value is searched. The input of only α and β is used when examining the positioner posture in various cases. Here, all of α, β, and γ are selected.

  When the weld line is parallel to the rotation axis of the positioner, there may be countless solutions that satisfy α and β. Therefore, a search is performed with one of the rotation shafts of the positioner fixed as follows. That is, the operator can select the fixed axis of the positioner while referring to the condition setting screen of FIG. When the first axis of the positioner is selected as the fixed axis, the positioner posture in a state where the first axis of the positioner is fixed is retrieved. On the other hand, when the second axis of the positioner is selected as the fixed axis, the positioner posture in a state where the second axis of the positioner is fixed is retrieved. When the rotation axis is selected, the operator inputs the value of the inclination angle of the fixed axis of the selected positioner. For example, when the first axis is selected as the fixed axis, the angle θ1 with respect to the vertical line of the first axis is input, and when the second axis is selected as the fixed axis, the inclination angle θ2 with respect to the horizontal plane of the second axis is input. When neither the first axis nor the second axis is selected as the fixed axis, it is selected that the positioner axis is not fixed. Here, no fixed axis is set.

  At this time, the operator can select in advance whether or not to guide the welding robot to the positioner position selected and determined based on the search result while referring to the condition setting screen of FIG. If guidance is selected, the robot is guided to the reference position after the search is completed. On the other hand, if it is selected not to guide, the robot is not guided. Here, set to guide the robot. Further, at this time, the operator can set the maximum number of searches while referring to the condition setting screen of FIG. Here, a maximum search number of 10 is set. (Step 11).

  When the search conditions for the positioner positioning search are set in this way, the personal computer operates the positioner shaft operating ranges θ1 and θ2, whether the positioner shaft is fixed, whether the fixed shaft is one or two axes, etc. Based on the above, the search range of the positioner shaft inclination angle when the welding line formed by the surface B and the surface A of the workpiece model 30 is robot-welded is obtained (step 12).

  Next, the personal computer sets the inclination angle of the positioner shaft to an arbitrary value within the search range (step 13), and changes the positioner and the workpiece posture based on this value (step 14).

  Next, the personal computer calculates the inclination or rotation angle α, β, γ of the welding surface in the changed workpiece posture and the preset inclination or rotation angle α, β, γ of the welding surface (all 0.00 degrees). And the errors of Δα, Δβ, Δγ for each positioner angle are stored in a table (step 15). The error data of Δα, Δβ, and Δγ stored in the table is displayed together with the detection result on a screen (see FIG. 9 described later) that displays the detection result.

  Next, it is determined whether or not a search end condition specified in advance, for example, based on the number of calculations, is satisfied (step 16). If the search end condition is not satisfied, the positioner operating ranges θ1 and θ2 are determined. (Step 17), the process returns to the above-described step 13 and steps 13 to 16 are repeated.

  If the search end condition is satisfied, it is determined whether or not the inclination angles α and β and the rotation angle γ are selected as the search conditions (step 18). In the present embodiment, since the inclination angles α and β and the rotation angle γ are selected, the numerical values of θ1 and θ2 and the posture of the work with a small error in total of α, β, and γ are displayed on the screen (step 19). .

  If only the inclination angles α and β are selected, the numerical values of θ1 and θ2 and the posture of the work with small errors only by α and β and the posture of the work are displayed in order on the screen (step 20).

  FIG. 10 is an explanatory diagram showing a personal computer screen that displays search results. In FIG. 10, ten search results are stored in a table, and the first search result is displayed. The operator looks at the display on the screen in an interactive manner and displays the next search result stored in the table to determine the positioner shaft angles θ1 and θ2 that are most suitable for welding between the surface B and the surface A in an appropriate workpiece. Select and determine (step 21).

  When an appropriate positioner angle is selected by the operator, the personal computer moves the positioner and the workpiece to the selected angle position on the screen (step 22).

  Next, the personal computer determines whether or not a designation for guiding the robot is made in advance based on the search result (step 23).

  In the present embodiment, since the robot has been designated to be guided, the robot on the personal computer is guided to the welding surface or welding line selected on the screen (step 24), and the positioner positioning search is terminated. If no designation for guiding the robot is made, the positioner positioning search is terminated without guiding the robot.

  In this way, the optimum positioner shaft angle in horizontal fillet welding between the surface B and the surface A in the workpiece model 30 is determined. Thereafter, the inclination angle of the positioner when welding the portions other than the surface B and the surface A in the workpiece model 30 is sequentially searched.

  When the surface to be the reference surface of the workpiece is an arc surface, each arc surface is approximated to a flat surface by subdividing the arc surface, and then the tilt angle of the positioner is adjusted by performing the same operation. You can search.

  The search result is transmitted to, for example, a control computer of a welding robot that is an actual machine, and used for actual welding work. FIG. 15 is an apparatus system diagram showing the robot welding apparatus. In FIG. 15, a work 64 is supported by a positioner 65, and a welding robot 63 for welding a weld line of the work 64 is disposed. The welding robot 63 is connected to a robot controller device 61 as a control computer by communication means, and the welding robot 63 is controlled by the robot controller device 61. A personal computer 60 as a positioner setting device is connected to the robot controller device 61 by a communication cable 62, for example.

  The search result of the positioner inclination angle obtained by the personal computer 60 as the positioner setting device is sent to the robot controller device 61 via the communication cable 62. After the inclination angle of the positioner 65 is adjusted based on this search result, the welding robot The workpiece 64 is welded by 63.

  According to the present embodiment, the positioner angle that realizes a welding posture in horizontal fillet welding, lateral welding, vertical welding, and the like is not limited to downward welding, and can be determined safely and accurately in a short time. In addition, by adopting a general-purpose offline teaching system that can register various robot systems, not only the positioner mechanism but also the positioner angle that realizes the welding posture can be determined safely and accurately in a short time. it can. Therefore, by performing actual welding with the positioner angle determined by this method, a stable product with high welding quality can be obtained.

  In the present embodiment, there are no obstacles for the robot to access other than the positioner angle as the standard for the operator to select the optimal one from the candidates shown as the PC search results, and the shortest For example, whether the route is connected or not.

  In the present embodiment, the optimum positioner angle in the horizontal fillet welding of the surface A and the surface B in the work model 30 shown in FIG. 6 is determined by offline teaching using a personal computer. By providing the means, it can be used in an actual robot system.

  Here, a method for creating a teaching program using the offline teaching apparatus as the basis of the present invention will be described.

  Off-line teaching is a teaching program for workpieces to be welded by displaying peripheral devices such as workpieces, robots, positioners, etc. in the virtual space of the computer, and the operator guiding the virtual robots through a personal computer input device such as a mouse or keyboard. It can be called virtual teaching performed on a computer.

FIG. 16 is a flowchart showing a method for creating a teaching program using the offline teaching apparatus. In FIG. 16, a teaching program is created by the following procedure.
(1) First, a part model to be a part of the work model is created. The part model is created, for example, by selecting the shape of a figure with a button displayed on a personal computer screen and then inputting the dimensions. In order to create a part model, there is a 2D input method in which a cross-sectional shape is input and a plate thickness is input in addition to such a method of entering dimensions.
(2) Next, a work model is created.

A work model is created by moving the created part models and combining them like building blocks. After the combination, in order to indicate that the parts of the work model are integrated, parent-child designation is performed with the base material as the parent and each member as the child. This is a work equivalent to temporary attachment at an actual work site.
(3) Next, the work model is arranged.

The work model is placed on the robot system in the virtual space as in the actual system. After the placement, it is instructed through the screen that the work model is attached to the positioner.
(4) Next, a teaching program is created.

  That is, teaching work on an actual line is realized in a virtual space on a computer. In teaching in the virtual space, first, the position angle is entered numerically on the screen to determine the workpiece posture. Next, in order to guide the robot, the robot tip position XYZ is designated by a number, for example. Then, the robot position is changed according to the number. When the robot arrives at a position to be moved in the virtual space, the position is stored by issuing a position determination instruction from the keyboard. By repeating such operations, a teaching program is created in the virtual space.

In the teaching, in addition to the work of creating the robot trajectory in the virtual space, all control commands that need to be input by actual machine teaching such as arc ON can be input.
(5) Next, simulation (reproduction) is performed.

The validity of the teaching program created by simulation in the virtual space is confirmed.
The following are examples of simulation functions.

  (A) An interference check between the robot and the workpiece is performed. That is, when the teaching program is created so as to pass an illegal route, or when a narrow part where the torch interferes is forcibly taught, the interference part is displayed in red during the simulation, and a warning is prompted.

  (B) An instruction error check is performed. That is, a warning is issued when an instruction is inserted at an illegal position in the teaching program, or when an illegal combination of instructions is set.

  (C) An operating range check is performed. That is, it is possible to confirm in advance whether or not the limit of each axis of the robot is exceeded by the teaching program created by simulation and whether or not the robot enters a singular point.

In this case, by using the software of the actual robot as it is in the simulation, a highly accurate simulation is possible, and the checks of (a), (b), and (c) are more accurate.
(6) Save the program.

  Since the results of the above checks (a), (b), and (c) can be left as a record, it is possible to correct the defective part collectively after the simulation is finished.

  Thus, according to the off-line teaching, it is possible to create a teaching program while saving work and ensuring safety. Therefore, off-line teaching is an effective teaching means similar to or in place of actual machine teaching.

  The positioner setting method for a welding robot according to the present invention is capable of positioning a positioner that supports a workpiece when performing automatic welding using a welding robot in a short time in a computer interactive manner in a short time. It is particularly useful in the field of automatic welding using

It is a block diagram of the apparatus applied to the positioner setting method of the welding robot which concerns on embodiment of this invention. It is explanatory drawing which shows the inclination angle (alpha) of a welding surface. It is explanatory drawing which shows the inclination angle (beta) of a welding surface. It is explanatory drawing which shows the rotation angle (gamma) of a welding surface. It is explanatory drawing of the reference line at the time of calculating | requiring the rotation angle (gamma) of a workpiece | work. It is a figure which shows the positional relationship of the weld line of a work model, and a positioner axis | shaft. It is a figure which shows the flow of the positioner setting method of the welding robot which concerns on embodiment of this invention. It is a figure which shows the personal computer screen at the time of search condition setting. It is a figure which shows another personal computer screen at the time of search condition setting. It is a figure which shows the personal computer screen which displays a search result. It is a figure which shows the board surface of horizontal fillet welding. It is a figure which shows the board surface of downward fillet welding. It is a perspective view of a real work. FIG. 14 is a front view of FIG. 13. It is an apparatus system diagram showing a robot welding apparatus. It is a figure which shows the flow of offline teaching. It is explanatory drawing which shows a prior art.

Explanation of symbols

1: Search condition setting unit 2: Reference plane setting unit 3: Work posture calculation preparation unit 4: Posture display unit 5: Search range setting unit 6: Search and ranking unit 7: Work model data 8: Search range data 9: Positioner Value candidate group 11: vertical line 12: base metal side welding surface 12a: normal line 13: vertical plate side welding surface 13a: normal line 14: bisector (reference line)
15: Line perpendicular to the base material surface (reference line)
16: Arc surface 16a: Welding point 16b: Line perpendicular to tangent at welding point 16a 17: Base material surface 18: Standing plate surface 19: Line perpendicular to the joining line 20: Arc 21: Welding point 22: Extension of arc radius Line 23: Workpiece 24: Welding line 30: Workpiece model 31: Positioner first axis 32: Positioner second axis 33: Plate body 34: Plate body 36: Weld surface 36a: Normal line 37: Weld surface 37a: Normal 38: Reference line for obtaining the rotation angle γ 41: Welding surface 42: Reference line for obtaining the rotation angle γ 43: Point 44: Standing plate 45: Welding line 46: Reference line for obtaining the rotation angle γ 47: End point 48: Welding line 49: Point 50: Arc 51: Welding point 52: Tangent line 53: Reference line 54 for obtaining the rotation angle γ: Welding surface 55: Base material surface 56: Standing plate surface 58: Welding line 60 : Positioner setting device (PC)
61: Robot controller 62: Communication cable 63: Welding robot 64: Work 65: Positioner

Claims (11)

  In a welding robot positioner setting method for setting a position of the positioner so that a workpiece to be welded is placed on a positioner of the welding robot and the workpiece is arranged in a desired position with respect to the welding torch, the positioner of the positioner is connected to a computer. A step of reading a three-dimensional model of the workpiece together with mechanism information, a step of instructing at least one welding surface or a line of a member to be welded of the model, and an inclination of a welding part from the indicated welding surface or line information A step of determining a reference line to be determined by calculation, a step of setting α and β as angles at which the reference line is inclined from the vertical direction in two directions orthogonal to each other, and setting α and β as a target angle of the workpiece, The workpiece model is moved within an allowable range from the positioner mechanism, and the α and β are within a target angle range 1 Positioner method of setting welding robot, characterized in that it comprises a step of determining by calculation the positioner positions of a plurality of combinations, a is.   In a welding robot positioner setting method for setting a position of the positioner so that a workpiece to be welded is placed on a positioner of the welding robot and the workpiece is arranged in a desired position with respect to the welding torch, the positioner of the positioner is connected to a computer. A step of reading a three-dimensional model of the workpiece together with mechanism information, a step of instructing at least one welding surface or a line of a member to be welded of the model, and an inclination of a welding part from the indicated welding surface or line information A step of determining a reference line to be determined by calculation, and an angle formed by the reference line with respect to a vertical direction when the reference line is projected onto a plane orthogonal to the plane including the welded portion, and a surface including the welded portion The angle formed by the reference line relative to the vertical direction when the reference line is projected is β, and α and β are set as the target angle of the workpiece. And a step of calculating one or a plurality of combination positioner positions where α and β are within a target angle range by moving the work model within a range allowed by the mechanism of the positioner. Positioner setting method of welding robot characterized by   When the welding surface is a plane, the step of designating the welding surface is performed by clicking the position of three points on the welding surface on the display screen of the computer and three-dimensional coordinates of the three points on the welding surface. (X11, y11, z11), (x12, y12, z12), (x13, y13, z13) designating CAD data previously input by clicking one point on the welding surface on the display screen 3. The positioner setting method for a welding robot according to claim 1, wherein a surface equation is obtained from the surface information.   The position setting method for a welding robot according to claim 1, wherein the reference line varies depending on a welding posture.   The position setting method for a welding robot according to claim 4, wherein the reference line is a line obtained by dividing the normal line of two welding surfaces into two equal parts when the welding posture is downward welding. .   5. The welding robot according to claim 4, wherein the reference line is a line perpendicular to a welding surface on a base metal side or a line perpendicular to a welding surface on a standing plate side when a welding posture is horizontal. Positioner setting method.   5. The positioner for a welding robot according to claim 4, wherein when the welding surface is an arc surface, the reference line is a line perpendicular to a tangent at a welding point and passing through the center of the arc. Setting method.   When the rotation angle around the vertical line of the workpiece model is γ, the step of calculating the positioner position of one or a plurality of combinations in which α and β are within the target angle range is calculated in addition to α and β The position setting method for a welding robot according to any one of claims 1 to 7, wherein the combination is calculated so that γ also falls within a target angle range.   The welding robot positioner setting method according to any one of claims 1 to 8, further comprising a step of guiding a robot on a computer to a welding surface or a welding line based on a positioner position obtained by the calculation. .   10. The welding robot according to claim 1, further comprising a step of calculating a positioner position while fixing one rotation shaft when the positioner has a plurality of rotation shafts. 11. Positioner setting method.   11. The method according to claim 1, further comprising a step of temporarily storing a plurality of combinations of positioner positions obtained by the calculation in a table of a computer and displaying the positions on a screen based on a display command. The welding robot positioner setting method described.

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