Instruction device

Abstract

The present application provides a teaching device capable of improving the work efficiency of teaching the action of a welding robot. The teaching device (3) comprises: a trajectory generation unit (311) for generating the action trajectory of the welding robot, the action trajectory of the welding robot taking the position of a specified welding torch as a starting point and setting the position of the specified welding torch as an ending point via a plurality of teaching points; and a display control unit (312) for displaying the generated action trajectory in overlap with the welding object contained in the image captured by a capturing unit (4), the trajectory generation unit (311) generating one or more via points between adjacent teaching points.

Description

Technical Field

[0001] This invention relates to teaching devices. Background Technology

[0002] Patent Document 1 discloses a motion teaching system for teaching actions of a welding robot. In this motion teaching system, during motion teaching, the welding torch located at the end of the robot arm is replaced with a camera unit. Furthermore, based on the position information of the welding part generated from the image captured by the camera unit, and the position and posture information of the robot arm when the image was captured, a motion trajectory based on the position and posture of the robot arm required for welding the welding part is generated, and the motion trajectories of each welding part are synthesized to generate teaching data.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-150930 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the motion teaching system of Patent Document 1, before motion teaching, an operation is performed to draw a line (welding line) on the object to be welded, representing the welding part of the object that will become the motion trajectory. Furthermore, this operation is performed by the operator drawing the welding line on the object to be welded using a pen. Therefore, in addition to the time-consuming operation, there is a possibility that the lines drawn by the pen may remain on the surface of the object to be welded.

[0008] Therefore, the object of the present invention is to provide a teaching device that can improve the efficiency of teaching actions for welding robots.

[0009] Methods for solving problems

[0010] One aspect of the present invention provides a teaching device comprising: a trajectory generation unit that generates a motion trajectory of a welding robot, the motion trajectory of the welding robot starting from a predetermined position of a welding torch and passing through multiple teaching points to set the predetermined position of the welding torch as the endpoint; and a display control unit that displays the generated motion trajectory overlapping with the welding object contained in an image captured by an imaging unit, the trajectory generation unit generating one or more passing points between adjacent teaching points.

[0011] According to this scheme, when the operator teaches multiple teaching points, a welding robot's motion trajectory can be generated, which involves moving from a specified welding torch position through multiple teaching points and back to the specified welding torch position. At this time, one or more passing points are added between adjacent teaching points to generate the motion trajectory, so that the generated motion trajectory overlaps with the welding object contained in the captured image. Therefore, the operator can reduce the time spent generating the welding robot's motion trajectory.

[0012] In the above scheme, the teaching point can also be taught by the operator directly operating the welding robot according to the external force applied to it.

[0013] According to this scheme, operators can teach multiple teaching points to desired locations while directly operating the welding robot.

[0014] In the above scheme, the display control unit may also make the display method of the via point visually different from that of the teaching point by making the via point more prominent than the teaching point.

[0015] According to this scheme, unlike the teaching points taught by the operator, the waypoints generated by the teaching device can be displayed in a way that is easily visually confirmed by the operator.

[0016] In the above scheme, the trajectory generation unit may generate transit points before and after the relay teaching point, which is a teaching point other than the teaching point at the start and end of the welding, and calculate the distance between the generated transit point and the relay teaching point based on the distance between the relay teaching point and other teaching points located adjacent to the relay teaching point on the rear or front side of the relay teaching point or the welding speed.

[0017] According to this scheme, the path points generated before and after the relay teaching point can be generated at appropriate positions without the operator's effort, taking into account the size of the welding object, welding speed, etc.

[0018] In the above scheme, the trajectory generation unit can generate the approach point or the retreat point by adjusting the direction of the welding torch's movement in a way that allows the welding robot to move without interfering with the object when the welding torch moves from the approach point toward the teaching point that becomes the start position of welding or moves from the teaching point that becomes the end position of welding toward the retreat point.

[0019] According to this scheme, approach and retreat points can be generated at appropriate locations based on the shape of the object being welded without requiring the operator's effort.

[0020] In the above scheme, the display control unit may visually differentiate the display method of the motion trajectory based on the empty stroke of the welding torch without generating an electric arc from the display method of the motion trajectory other than the empty stroke motion trajectory.

[0021] According to this scheme, the motion trajectory of the welding zone and the motion trajectory based on the idle stroke can be displayed in a way that is easy for the operator to visually distinguish.

[0022] In the above scheme, it is also possible that when the trajectory generation unit generates the motion trajectory based on the empty stroke, the welding robot that performs the motion based on the empty stroke can adjust the movement direction of the welding torch in a way that does not interfere with the object.

[0023] According to this scheme, the motion trajectory of a welding robot that moves without interfering with objects can be generated without the operator's effort, based on the motion of the idle stroke.

[0024] In the above scheme, the trajectory generation unit may also generate transit points at the positions indicated by the operator on the image.

[0025] According to this scheme, via points can be generated at any location specified by the operator.

[0026] In the above scheme, the trajectory generation unit may also generate a number of transit points set by the operator between the teaching points.

[0027] According to this scheme, any number of via points specified by the operator can be generated between each teaching point.

[0028] Invention Effects

[0029] According to the present invention, a teaching device is provided that can improve the efficiency of teaching actions for welding robots. Attached Figure Description

[0030] Figure 1 This is a diagram illustrating the outline structure of a robot teaching system that includes a teaching device for implementing an embodiment.

[0031] Figure 2 This is a schematic diagram used to illustrate the teaching points set on the workpiece.

[0032] Figure 3 It is a schematic diagram used to illustrate the points through which the passage passes.

[0033] Figure 4 This is a schematic diagram illustrating an example of a motion trajectory that overlaps with the workpiece contained in the captured image.

[0034] [Explanation of Labels in the Attached Image]

[0035] 1…robot control device, 2…manipulator, 3…teaching device, 4…camera unit, 5…display unit, 11…control unit, 12…storage unit, 13…communication unit, 31…control unit, 32…storage unit, 33…communication unit, 100…robot teaching system, 311…trajectory generation unit, 312…display control unit. Detailed Implementation

[0036] Preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that elements labeled with the same reference numerals in the drawings have the same or identical structure. Furthermore, the drawings are schematic, and therefore the dimensions and proportions of the constituent elements differ from actual dimensions.

[0037] Figure 1 This is a diagram illustrating the general structure of a robot teaching system 100 including the teaching device 3 of the embodiment. The robot teaching system 100 includes, for example, a robot control device 1, a robotic arm 2, a teaching device 3, a camera 4, and a display 5. It should be noted that the camera 4 and the display 5 may also be included within the teaching device 3.

[0038] The robot control device 1 is connected to the teaching device 3, the robot control device 1 is connected to the robotic arm 2, and the teaching device 3 is connected to the camera unit 4 and the display unit 5 via cables, wireless communication, etc.

[0039] The robotic arm 2 is a welding robot that performs arc welding on a workpiece (base material) according to the welding conditions set in the robot control device 1. The robotic arm 2 has, for example, a multi-joint arm mounted on a fixed base component such as a factory floor, and a welding torch connected to the front end of the multi-joint arm as one of the working tools.

[0040] The robotic arm 2 is also a collaborative robot that operates in conjunction with humans and is capable of moving in response to external forces. The operator can also directly apply external force to the robotic arm 2 with their hand, and operate it directly (direct teaching). It should be noted that the welding robot of this invention includes both robots requiring safety barriers that do not rely on human cooperation and collaborative robots that rely on human cooperation.

[0041] Robot control device 1 is a control unit that controls the movements of robotic arm 2 according to pre-set welding conditions. These welding conditions include data items such as welding parameters, welding start position, welding end position, welding distance, torch position, and attitude. The welding parameters also include data items such as welding current, welding voltage, welding speed, wire feed speed, and workpiece thickness.

[0042] The robot control device 1 includes, for example, a control unit 11, a storage unit 12, and a communication unit 13. The control unit 11 is a processor that controls the robotic arm 2 by executing work programs stored in the storage unit 12.

[0043] The storage unit 12 is a computer-readable recording medium that stores programs for implementing various functions of the robot control device 1, as well as various data used in the programs. The communication unit 13 is a communication interface that controls communication with the robot arm 2 and the teaching device 3 connected via a network or the like.

[0044] It should be noted that the robot control device 1 may also include a welding power supply unit. For example, the welding power supply unit supplies welding current and welding voltage to the robot arm 2 according to predetermined welding conditions to generate an electric arc between the tip of the welding wire and the workpiece. It should also be noted that the welding power supply unit can be separately equipped on the robot from the control device 1.

[0045] The teaching pendant 3 is a device for processing actions such as teaching the robot arm 2 to the operator, and is, for example, a flat-panel teaching pendant. The teaching pendant 3 includes, for example, a control unit 31, a storage unit 32, and a communication unit 33.

[0046] The control unit 31 is a processor that controls the various parts of the teaching pendant 3 by executing programs stored in the storage unit 32. The functions of the control unit 31 will be described later.

[0047] The storage unit 32 is a computer-readable recording medium that stores programs for implementing various functions of the teaching pendant 3, as well as various data used in those programs. The communication unit 33 is a communication interface that controls communication with the robot control device 1, the camera unit 4, and the display unit 5, which are connected via a network.

[0048] The imaging unit 4 is, for example, a 3D camera equipped with a distance measurement sensor, and also functions as a 2D camera. The imaging unit 4 is preferably positioned to capture images of a workspace containing at least the workpiece. It should be noted that the imaging unit 4 can also be equipped with the teaching pendant 3.

[0049] Distance measurement sensors are sensors that can determine the distance to an object. Examples of distance measurement sensors include LiDAR (Light Detection and Ranging) sensors, millimeter-wave sensors, and ultrasonic sensors.

[0050] Here, the imaging unit 4 does not necessarily include a distance measurement sensor; it can be equipped with a distance measurement sensor separately from the imaging unit 4, or the distance measurement sensor can be omitted. If the distance measurement sensor is omitted, it is preferable to calculate the three-dimensional coordinate data corresponding to the object based on multiple images of the object captured from multiple different positions. In this case, a three-dimensional measurement method based on a known stereo method can be used.

[0051] The display unit 5 is, for example, a display device with a touch panel, which displays images (2D and 3D) of the subject captured by the imaging unit 4, and accepts input based on operator instructions. It should be noted that the display unit 5 can also be equipped with the teaching pendant 3.

[0052] like Figure 1 As shown, the control unit 31 of the teaching device 3 is a functional structure that includes, for example, a trajectory generation unit 311 and a display control unit 312.

[0053] The trajectory generation unit 311 generates the motion trajectory of the robot arm 2. The motion trajectory of the robot arm 2 starts from the specified front end position of the welding torch and ends at the specified front end position of the welding torch by passing through multiple teaching points.

[0054] As a predetermined position of the welding torch tip, for example, it is preferable to register the position of the welding torch tip of the robot arm 2 contained in the image captured by the imaging unit 4, and use the registered position as the original position (origin position).

[0055] The teaching point is taught through direct operation by the operator, who activates the robotic arm 2 based on the external force applied to it. (Refer to...) Figure 2 To explain in detail.

[0056] exist Figure 2 The image displays three teaching points Ta, Tb, and Tc. These three teaching points are located at both ends and corners of the welding line formed by the intersection of the workpiece Wa on the base plate and the L-shaped workpiece Wb. Specifically, teaching point Ta is located at the welding start position, teaching point Tb is located at the corner of the L-shape, and teaching point Tc is located at the welding end position. Here, teaching points other than those located at the welding start and end positions (e.g., teaching point Tb) are also referred to as relay teaching points.

[0057] It should be noted that the teaching point can be set using a general teaching pendant, or it can be set based on the workpiece's point group data, image data detection plane, and intersection lines between planes, which can be determined by the robot coordinate system. In the latter case, it is preferable to place a marker (e.g., an AR marker) with a fixed positional relationship to the robot arm 2 and which can be determined by the robot coordinate system near the workpiece, and use the imaging unit 4 to photograph the workpiece and the marker. Thus, the positions of the workpiece and the imaginary model of the robot arm 2 displayed on the screen along with the marker can be determined as their positions in the robot coordinate system based on the specific position of the marker (e.g., the corner or center of the marker).

[0058] Figure 1 The trajectory generation unit 311 generates multiple transit points other than the teaching point when generating the motion trajectory of the robot arm 2 passing through the teaching point. (See reference...) Figure 3 To explain in detail.

[0059] exist Figure 3 The points shown are: Va, Vg, and Vb, which are generated at the original position; Vb, which is generated behind the teaching point Ta, which indicates the welding start position; Vc and Vd, which are generated before and after the relay teaching point Tb at the corner; Ve, which is generated in front of the teaching point Tc, which indicates the welding end position; and Vf, which is generated between the Ve and the welding end point Vg.

[0060] Here, at the corner of the workpiece, the welding torch's posture (forward angle and backward angle) needs to be changed from the basic posture in a way that prevents the welding torch from colliding with the workpiece. Therefore, the interval for changing the welding torch's posture from the basic posture is set before and after the relay teaching point Tb at the corner, and the starting point and ending point of this interval are respectively set with transit points Vc and Vd.

[0061] In this case, the basic posture is the same as the welding start position, moving from the teaching point Ta to the via point Vc, and the basic posture is the same as the welding end position, moving from the via point Vd to the teaching point Tc. Furthermore, at the intermediate teaching point Tb, it becomes an intermediate posture between the basic posture of the welding start position and the basic posture of the welding end position.

[0062] The distance from the transit point Vc to the relay teaching point Tb can be the same as or different from the distance from the relay teaching point Tb to the transit point Vd. For example, a specific distance can be arbitrarily determined, such as 20mm or 30mm.

[0063] Alternatively, when generating transit points Vc and Vd, the distances from transit point Vc to relay teaching point Tb and from relay teaching point Tb to transit point Vd can be varied based on the distances between adjacent teaching points Ta and relay teaching points Tb, and between adjacent relay teaching points Tb and teaching points Tc. For example, if the distance between adjacent teaching points is shorter than a predetermined distance, the distance can be shortened to match the degree of shortening.

[0064] Furthermore, when generating the transit points Vc and Vd, the distances from the transit point Vc to the relay teaching point Tb and from the relay teaching point Tb to the transit point Vd can be varied based on the welding speed. For example, the faster the welding speed, the longer each distance can be.

[0065] Here, the interval from the teaching point Ta, indicating the start position of welding, to the teaching point Tc, indicating the end position of welding, becomes the welding interval where an electric arc is generated and the welding torch moves. On the other hand, the interval in the motion trajectory from the start point Va to the end point Vg, excluding the welding interval, becomes the so-called no-load (no-arc) interval where the welding torch moves without generating an electric arc.

[0066] The trajectory generation unit 311 has the following function: when generating a motion trajectory based on idle travel, it adjusts the direction of movement of the welding torch in a manner that allows the robot arm 2, which moves based on idle travel, to move without interfering with the object. This function will be explained below.

[0067] The positions of the approach point Vb and the retreat point Ve are preset based on the welding start position and the welding end position. For example, the approach point Vb and the retreat point Ve are set at a specific position after pulling the tip of the welding torch 50mm away from the welding position in the direction of the length of the welding torch (tool Z direction) from the teaching point Ta, which indicates the welding start position, and the teaching point Tc, which indicates the welding end position.

[0068] When setting the approach point Vb and the retreat point Ve, if the robot arm 2 interferes with the object, it can either continuously pull the welding torch along its length until the interference with the object is eliminated, or change the direction of pulling the welding torch to another direction until the interference with the object is eliminated. In this case, it is preferable to adjust the direction of pulling the welding torch to shorten the production cycle time (movement time).

[0069] Whether robotic arm 2 interferes with an object can be determined by simulating a hypothetical model of robotic arm 2. A 3D model of robotic arm 2 can be used as the hypothetical model. Alternatively, schematic diagrams, drawings, or real-life images can also be used.

[0070] When determining whether interference exists, it can also be determined whether robot arm 2 interferes with the object based on whether the 3D model of robot arm 2 is in contact (including overlap) with the point data set obtained by the distance measuring sensor. In this case, if the 3D model is in contact with the point data set, it is determined that robot arm 2 interferes with the object.

[0071] Furthermore, when generating a motion trajectory from the start point Va to the approach point Vb or from the retreat point Ve to the end point Vg, the trajectory generation unit 311 determines whether the robot arm 2 interferes with the object. If the robot arm 2 interferes with the object, a new transit point is generated at a position where interference can be avoided. This will be explained in detail below.

[0072] In generation Figure 3 In the case of a motion trajectory from the start point Va to the approach point Vb, since the robot arm 2 does not interfere with the object, the trajectory generation unit 311 does not generate a new transit point. In this case, the trajectory generation unit 311 generates a motion trajectory from the start point Va to the approach point Vb.

[0073] On the other hand, in generating Figure 3 In the case of a motion trajectory from the retraction point Ve to the motion end point Vg, due to interference between the robot arm 2 and the workpiece Wb, the trajectory generation unit 311 generates a new transit point Vf. In this case, the trajectory generation unit 311 generates a motion trajectory from the retraction point Ve to the transit point Vf and a motion trajectory from the transit point Vf to the motion end point Vg.

[0074] Here, to avoid interference, the robot arm 2 and the welding torch can be moved along the direction of the imaging unit 4 in a way that eliminates interference, and a new transit point is generated at the new position. When the imaging unit 4 is imaging the robot arm 2, since there is no object between the imaging unit 4 and the robot arm 2, the accuracy of interference elimination can be improved.

[0075] Figure 1 The display control unit 312 shown displays the motion trajectory generated by the trajectory generation unit 311 overlapping the workpiece contained in the captured image. (See reference...) Figure 4 To explain in detail.

[0076] Figure 4 This is an example of an image P captured by the imaging unit 4. Image P includes a workpiece Wa on a base plate, an L-shaped workpiece Wb, a robot arm 2, and a marker M. The robot arm 2 can be either a hypothetical model or a real robot arm 2.

[0077] In addition, in the captured image P, the motion trajectory Lw of the welding zone generated in conjunction with the welding line formed at the intersection of workpiece Wa and workpiece Wb, and the motion trajectory La generated in conjunction with the movement based on the idle stroke are displayed overlapping with workpiece Wa and workpiece Wb.

[0078] The display control unit 312 can also display the teaching point and the path point together when displaying the motion trajectory Lw and the motion trajectory La. In this case, it is preferable to make the display method of the path point visually different from that of the teaching point, so that the path point is more prominent than the teaching point. The different display methods can include, for example, colors, patterns, and shapes. Thus, in addition to the teaching point taught by the operator, the path point generated by the trajectory generation unit 311 can also be displayed in a display method that is easy for the operator to visually recognize.

[0079] Furthermore, the display control unit 312 preferably displays the motion trajectory La based on the idle stroke in a visually different manner from the motion trajectory Lw other than the motion trajectory La based on the idle stroke. This allows the motion trajectory Lw in the welding zone and the motion trajectory La based on the idle stroke to be displayed in a way that is easily distinguishable to the operator.

[0080] As described above, according to the teaching device 3 of the embodiment, when the operator teaches multiple teaching points, a motion trajectory of the robot 2 is generated from the original position of the welding torch through multiple teaching points back to the original position of the welding torch. At this time, by adding one or more passing points between adjacent teaching points to generate the motion trajectory, the generated motion trajectory can be displayed overlapping with the workpiece contained in the captured image. As a result, the operator can reduce the time spent generating the motion trajectory of the robot 2.

[0081] Therefore, the teaching device 3 according to the embodiment can improve the efficiency of teaching the robot arm 2.

[0082] [Variation Example]

[0083] It should be noted that the present invention is not limited to the embodiments described above, and various other forms can be implemented without departing from the spirit of the invention. Therefore, the above embodiments are merely illustrative in all respects and are not intended to be limiting.

[0084] For example, in the above embodiment, the trajectory generation unit 311 generates transit points based on the location of the original position, teaching points, etc., but is not limited to this. Transit points may also be generated further at the locations indicated (e.g., tapped) by the operator on the captured image. In addition, transit points displayed on the captured image may be specified (e.g., dragged) to make them movable.

[0085] Furthermore, in the above embodiment, the trajectory generation unit 311 generates a transit point between each teaching point, but it is not limited to this. The operator can also arbitrarily set the number of transit points generated between each teaching point. For example, the position can be recorded whenever the angle of each axis of the robot 2 changes by a predetermined angle (e.g., 5 degrees), and unnecessary positions are eliminated as much as possible within a range that allows the welding torch's posture to change smoothly, with the remaining positions being generated as transit points.

[0086] When multiple transit points are generated between teaching points, the transit point located closer to the relay teaching point at the corner will increase the degree of change in the welding torch's posture.

Claims

1. A teaching device, wherein, The teaching device includes: The trajectory generation unit generates the motion trajectory of the welding robot, which starts from the position of the specified welding torch and ends at the position of the specified welding torch by passing through multiple teaching points. as well as The display control unit overlays the generated motion trajectory onto the welding object contained in the image captured by the imaging unit. The trajectory generation unit generates one or more transit points between adjacent teaching points.

2. The teaching device according to claim 1, wherein, The teaching point is taught through direct operation by the operator, who activates the welding robot by applying an external force to it.

3. The teaching device according to claim 1, wherein, The display control unit makes the display method of the via point visually different from that of the teaching point in such a way that the via point is more prominent than the teaching point.

4. The teaching device according to claim 1, wherein, When the trajectory generation unit generates the transit points before and after the relay teaching points (other than the teaching points at the start and end positions of welding), it calculates the distance between the generated transit points and the relay teaching points based on the distance between the relay teaching points and other teaching points located adjacent to the relay teaching points on the rear or front side of the relay teaching point, or the welding speed.

5. The teaching device according to claim 1, wherein, When the trajectory generation unit generates an approach point behind the welding start position or a retreat point in front of the welding end position, the welding robot can adjust the direction of the welding torch's movement in a manner that allows it to move without interfering with objects, so as to generate the approach point or the retreat point.

6. The teaching device according to claim 1, wherein, The display control unit makes the display method of the motion trajectory based on the idle stroke of the welding torch without generating an electric arc visually different from the display method of the motion trajectory other than the motion trajectory based on the idle stroke.

7. The teaching device according to claim 6, wherein, When generating the motion trajectory based on the empty stroke, the trajectory generation unit adjusts the direction of the welding torch's movement in a manner that allows the welding robot, which performs the motion based on the empty stroke, to move without interfering with the object.

8. The teaching device according to claim 1, wherein, The trajectory generation unit generates the transit point at the location indicated by the operator on the image.

9. The teaching device according to claim 1, wherein, The trajectory generation unit generates a number of transit points set by the operator between the teaching points.

Images