Robot travel platform position determination device, method, and recording medium

Abstract

The present invention provides a robot traveling pallet position determination device, method, and program that can efficiently determine the position of a robot traveling pallet. The robot traveling pallet position determination device (D) of the present invention determines the position of a robot traveling pallet that moves with a robot that performs a prescribed work on a workpiece using a tool provided at the front end, and includes: an interference range information storage section (21) that stores interference range information indicating an interference range in which the robot interferes in a prescribed surrounding environment; an entry direction processing section (12) that fixes the wrist rotation center point of the robot in the posture of the tool corresponding to a prescribed work position, and obtains the direction of the arm of the robot as an arm entry direction in such a manner that the arm does not overlap the interference range; and a position processing section (13) that obtains the position of the robot traveling pallet based on the arm entry direction obtained by the entry direction processing section (12).

Description

TECHNICAL FIELD

[0001] The present application relates to a robot traveling pallet position determination device, a robot traveling pallet position determination method, a robot traveling pallet position determination program, and a medium having the robot traveling pallet position determination program, which determines the position of a robot traveling pallet that carries a robot that performs a prescribed work on a workpiece. BACKGROUND

[0002] Robots that perform a prescribed work on a workpiece are used in various industrial fields due to the progress of their development. In order to cover a range larger than the range of motion of an arm, a robot is sometimes carried on a traveling pallet (slide) that moves the position of the robot itself. The robot performs a motion in accordance with motion data (motion program, teaching data, teaching program) of a motion that is taught in advance in correspondence with the purpose of the motion, but in the case where the robot is carried on a traveling pallet, the motion of the traveling pallet also needs to be determined and included in the motion data. A technique related to such motion data that includes the motion of the traveling pallet is disclosed, for example, in Patent Literature 1.

[0003] The production method of offline teaching data disclosed in this Patent Literature 1 is a production method of offline teaching data of a robot system that performs a continuous work on a workpiece while causing a slide of a mounting fixed base of a mobile robot to perform a motion, and has an initial setting step of setting work positions in the workpiece, an evaluation value calculation step of setting an exploration plane that passes through a robot origin that is a motion base point of the robot, so as to set the position of the slide in such a manner that a plurality of lattice points set in the exploration plane respectively coincide with the work positions on the workpiece, and calculating an evaluation value of each lattice point at the position of the slide, and a determination step of determining the position of the slide based on the evaluation value, and adopting the determined position of the slide as the offline teaching data of the robot.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2010-46753

[0007] However, in the movement of the traveling stage, it is necessary to determine the movement of the traveling stage in such a manner that the traveling stage and the robot do not interfere (come into contact) with other objects. In the patent document 1, the evaluation value is calculated by an evaluation function including the degree of interference or near miss in the posture of the welding robot, whether or not the slide is in the range of movement, and the like (for example, paragraph 0025), but in a case where inverse transformation cannot be performed or the evaluation value is low even if all the lattice points of a certain search plane are set as welding points, and the like, the position of the slide is determined again from the beginning by changing the search plane (for example, paragraphs 0028 and 0033), and thus there is room for improvement in the efficiency of the operation (information processing) of determining the position of the traveling stage in the patent document 1. SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The present application was made in view of the above-described circumstances, and an object thereof is to provide a robot traveling stage position determination device, a robot traveling stage position determination method, and a robot traveling stage position determination program, which can efficiently determine the position of a robot traveling stage.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] As a result of various studies by the present inventors, it has been found that the above-described object can be achieved by the present application described below. That is, a robot traveling stage position determination device according to one aspect of the present application determines the position of a robot traveling stage that moves a robot that performs a prescribed operation on a workpiece using a tool provided at a front end, and the robot traveling stage position determination device includes: an interference range information storage unit that stores interference range information indicating an interference range in which the robot interferes in a prescribed surrounding environment; an entry direction processing unit that fixes a wrist rotation center point of the robot in a posture of the tool corresponding to a prescribed operation position, and calculates a direction of an arm of the robot as an arm entry direction in such a manner that the arm does not overlap the interference range; and a position processing unit that calculates the position of the robot traveling stage based on the arm entry direction calculated by the entry direction processing unit.

[0012] Such a robot traveling stage position determination device calculates the direction of the arm of the robot in such a manner that the arm does not overlap the interference range before calculating the position of the robot traveling stage, and thus eliminates the situation where the process of calculating the position of the robot traveling stage is performed again from the beginning, and thus can efficiently determine the position of the robot traveling stage.

[0013] In another aspect, in the robot traveling vehicle position determination device described above, the approach direction processing section calculates the arm approach direction by searching in the circumferential direction of a circle centered on the wrist rotation center point in a plane including the wrist rotation center point. Preferably, in the robot traveling vehicle position determination device described above, the approach direction processing section calculates the arm approach direction in such a manner that the direction of the arm of the robot does not overlap the interference range and in such a manner that the direction of the arm of the robot is closest to a prescribed reference position. Preferably, the reference position is the front surface position of the workpiece.

[0014] Such a robot traveling vehicle position determination device searches in the circumferential direction of a circle centered on the wrist rotation center point in a plane including the wrist rotation center point, and thus can search for the arm approach direction with a relatively simple process.

[0015] In another aspect, in these robot traveling vehicle position determination devices described above, the work positions are a plurality of work positions arranged in a time series, the approach direction processing section calculates the arm approach direction for each of the plurality of work positions in the order of the time series, the position processing section calculates the position of the robot traveling vehicle for each of the plurality of arm approach directions calculated by the approach direction processing section, and the approach direction processing section calculates the current arm approach direction in such a manner that it is closest to the previous arm approach direction in the order of the time series.

[0016] Such a robot traveling vehicle position determination device calculates the current arm approach direction in such a manner that it is closest to the previous arm approach direction in the order of the time series, and thus can calculate the position of the robot traveling vehicle for each of a plurality of work positions arranged in a time series in such a manner that the robot can move smoothly.

[0017] In another aspect, in the above-described robot travel base position determination device, the position processing section sets an exploration plane in the arm approach direction obtained by the approach direction processing section and in which a robot origin, which is a movement base point of the robot, is located in the arm approach direction, sets the position of the robot travel base in such a manner that the robot origin coincides with each of a plurality of lattice points set in the exploration plane, calculates evaluation values of the respective lattice points at the position of the robot travel base, and obtains the position of the robot travel base based on the evaluation values. Preferably, in the above-described robot travel base position determination device, the position processing section also adopts the position of the robot travel base as offline teaching data of the robot. Preferably, in the above-described robot travel base position determination device, the evaluation values are obtained by an evaluation function including any one of a margin with respect to a specific posture of the robot, a margin with respect to a movement range boundary of each axis, interference in a posture of the robot, a degree of abnormal approach, a margin with respect to a movement range boundary of each axis of the robot travel base, and a movement amount with respect to a previous position. Preferably, in the above-described robot travel base position determination device, the robot has a first link having a first joint, a second link connected to the first link via a second joint, a third link having fourth and fifth joints and connected to the second link via a third joint, and an end effector connected to the third link via a sixth joint, and the tool is provided to the end effector, the position processing section sets the position of the robot travel base in the exploration plane including the arm approach direction obtained by the approach direction processing section in such a manner that the robot origin coincides with a plurality of points set in a circumferential direction of a circle having the position of the third joint as a center point, calculates evaluation values of the respective points at the position of the robot travel base, and obtains the position of the robot travel base based on the evaluation values.

[0018] Such a robot travel base position determination device can automatically and efficiently obtain an optimal position of a robot travel base.

[0019] A robot traveling dolly position determination method of one aspect of the present application determines a position of a robot traveling dolly that moves while carrying a robot that performs a prescribed work on a workpiece using a tool provided at a front end, and includes an interference range setting step that sets an interference range in which the robot interferes in a prescribed surrounding environment, an entry direction processing step that fixes a wrist rotation center point of the robot in a posture of the tool corresponding to a prescribed work position and obtains a direction of an arm of the robot as an arm entry direction in a manner that does not overlap with the interference range, and a position processing step that obtains the position of the robot traveling dolly based on the arm entry direction obtained by the entry direction processing step.

[0020] A robot traveling dolly position determination program of one aspect of the present application determines a position of a robot traveling dolly that moves while carrying a robot that performs a prescribed work on a workpiece using a tool provided at a front end, and functions as an interference range information storage section that stores interference range information indicating an interference range in which the robot interferes in a prescribed surrounding environment, an entry direction processing section that fixes a wrist rotation center point of the robot in a posture of the tool corresponding to a prescribed work position and obtains a direction of an arm of the robot as an arm entry direction in a manner that does not overlap with the interference range, and a position processing section that obtains the position of the robot traveling dolly based on the arm entry direction obtained by the entry direction processing section.

[0021] Such a robot traveling dolly position determination method and a robot traveling dolly position determination program obtain a direction of an arm of a robot in a manner that does not overlap with an interference range before obtaining a position of a robot traveling dolly, and thus eliminate a situation in which a process of obtaining a position of a robot traveling dolly is performed from the beginning, and thus can efficiently determine a position of a traveling dolly.

[0022] Effects of the Invention

[0023] The robot traveling dolly position determination device, the robot traveling dolly position determination method, the robot traveling dolly position determination program, and the medium having the robot traveling dolly position determination program of the present application can efficiently determine a position of a traveling dolly. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a diagram for explaining a schematic configuration of a welding system that includes the robot traveling dolly position determination device of the embodiment.

[0025] Figure 2 FIG. 1 is a diagram showing an example of a workpiece.

[0026] Figure 3 FIG. 2 is a block diagram showing the structure of the robot traveling vehicle position determination device.

[0027] Figure 4 FIG. 3 is a diagram for explaining the determination processing of the position and posture of a welding torch as an example of a tool.

[0028] Figure 5 FIG. 4 is a diagram for explaining the exploration processing of the arm accessible direction.

[0029] Figure 6 FIG. 5 is a diagram for explaining the determination processing of the arm accessible direction.

[0030] Figure 7 FIG. 6 is a diagram for explaining the exploration plane and the lattice points on the exploration plane.

[0031] Figure 8 FIG. 7 is a flowchart showing the operation of the robot traveling vehicle position determination device.

[0032] Figure 9 FIG. 8 is a diagram for explaining the case where the robot origin is explored in the circumferential direction of a circle centered on the position of the third joint of the robot in the exploration plane.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] TC Off-line teaching device

[0035] D Robot traveling vehicle position determination device

[0036] MR Robot

[0037] 1 Control processing section

[0038] 2 Storage section

[0039] 3 Input section

[0040] 4 Display section

[0041] 11 Control section

[0042] 12 Accessible direction processing section

[0043] 13 Position processing section

[0044] 21 Interference range information storage section DETAILED DESCRIPTION

[0045] One or more embodiments of the present application will be described below with reference to the accompanying drawings. However, the scope of the application is not limited to the disclosed embodiments. Note that structures denoted by the same reference numerals in different drawings represent the same structures, and the description thereof is appropriately omitted. In this specification, a reference numeral denoted by an omitted suffix represents a general case, and a reference numeral denoted by a suffix represents a case where a structure is referred to individually.

[0046] The robot traveling dolly position determination device of the embodiment is a device that determines the position of a robot traveling dolly that moves a robot that performs a prescribed work on a workpiece using a tool provided at a front end. The robot traveling dolly position determination device (hereinafter, appropriately referred to as a "position determination device") includes an interference range information storage section that stores interference range information indicating an interference range in which the robot interferes in a prescribed surrounding environment; an approach direction processing section that fixes a wrist rotation center point of the robot in a posture of the tool corresponding to a prescribed work position, and obtains an approach direction of an arm of the robot so as not to overlap with the interference range; and a position processing section that obtains the position of the robot traveling dolly based on the approach direction of the arm obtained by the approach direction processing section. Hereinafter, the robot traveling dolly position determination device, the robot traveling dolly position determination method installed in the robot traveling dolly position determination device, and the robot traveling dolly position determination program will be described more specifically with the case where the robot traveling dolly position determination device is applied to a welding system as an example. Note that the robot traveling dolly position determination device, the method, and the program are not limited to the application to the welding system, and can be applied to any system using a robot traveling dolly that moves a robot.

[0047] Figure 1 is a diagram for explaining the outline structure of a welding system that includes the robot traveling dolly position determination device of the embodiment. Figure 2 is a diagram showing an example of a workpiece. Figure 3 is a block diagram showing the structure of the robot traveling dolly position determination device. Figure 4 is a diagram for explaining a determination process of the position and posture of a welding torch as an example of a tool. Figure 5 is a diagram for explaining an exploration process of an approach direction of an arm. Figure 6 is a diagram for explaining a determination process of an approach direction of an arm. Figure 6 A of is a directed line segment showing an approach direction of an arm, Figure 6 B of shows a case where a virtual robot model is arranged (drawn) along the approach direction of an arm shown in A of Figure 6 A of shows a case where a virtual robot model is arranged (drawn) along the approach direction of an arm shown in A of Figure 7is a view for explaining an exploration plane and a lattice point on the exploration plane. Figures 4 to 6 is a view obtained by viewing the robot MR from directly above, Figure 7 is a view obtained by viewing the robot MR from directly laterally.

[0048] The welding system SY provided with the robot traveling stage position determination device of the embodiment is, for example, as shown in Figure 1 is provided with a robot MR, a traveling stage SL, a positioner PS, a control device CL, a teach pendant TP, and an offline teaching device TC.

[0049] The traveling stage SL is a device that moves while carrying the robot MR that performs a prescribed work on a workpiece WK using a tool provided at a front end. The traveling stage SL is connected to the control device CL and acts in accordance with the control of the control device CL. The tool uses an appropriate implement corresponding to the prescribed work. In the present embodiment, since it is a welding system SY, the prescribed work is arc welding, and a tool example corresponding thereto is a welding torch WT. The traveling stage SL is capable of moving in three axes of an X axis in a front-rear direction, a Y axis in a left-right direction, and a Z axis in an up-down direction with respect to the workpiece WK, as shown in Figure 1 These X axis, Y axis, and Z axis are orthogonal to each other and constitute an XYZ orthogonal coordinate system (world coordinate system). Note that, in Figure 1 , the XYZ orthogonal coordinate system is illustrated overlapping the traveling stage SL in order to illustrate the directions in which the traveling stage SL is capable of moving, but the origin of the XYZ orthogonal coordinate system is set to coincide with a workpiece origin set at a prescribed position of the workpiece WK, as shown in Figure 2

[0050] More specifically, the traveling stage SL, in the example shown in Figure 1 , is provided with: a stage ST capable of moving in the X axis direction and the Y axis direction; a lifting section RF installed on the stage ST to raise and lower a rack PT in the Z axis direction and extending in the Z axis direction in a substantially "コ" (C) shape cross section; and the rack PT in the shape of a plate that mounts and fixes the robot RM.

[0051] The robot MR is a robot that is connected to the control device CL, acts in accordance with the control of the control device CL, and is provided with an arm having a plurality of joints, and is, for example, a multi-joint robot such as a vertical six-axis robot having six degrees of freedom of first to sixth joints J1 to J6. For example, in Figure 1 ​In the example shown, the robot MR is provided with a first link LK1 including a first joint J1, a second link LK2 connected to the first link LK1 via a second joint J2, a third link LK3 including fourth and fifth joints J4, J5 and connected to the second link LK2 via a third joint J3, and an end effector WR connected to the third link LK3 via a sixth joint J6. The arm of the robot MR is configured to include the first to third links and the first to sixth joints J1 to J6. In the present embodiment, the end effector WR at the front end is provided with a welding torch WT as an example of a tool, and the robot MR is capable of welding a workpiece WK by electric arc welding using a welding wire fed from the welding torch WT.

[0052] The positioner PS is a device that holds the workpiece WK in a manner capable of rotating about the two axes of the Y axis and the Z axis in θ1, θ2. The positioner PS is connected to the control device CL and operates in accordance with the control of the control device CL.

[0053] The teach pendant TP is a portable operation device connected to the control device CL and used for manually operating the travel carriage SL and the robot MR. In teaching (teaching) of the travel carriage SL and the robot MR using the teach pendant TP, the travel carriage SL and the robot MR are actually operated by manual operation, thereby teaching a movement path, a position, and the like of the travel carriage SL with respect to the workpiece WK and a movement path, a position, and the like of the welding torch WT with respect to the workpiece WK.

[0054] The off-line teaching device TC is a device that reproduces the travel carriage SL and the robot MR as a travel carriage model and an imaginary robot model in a virtual space of a computer, causes these travel carriage model and the imaginary robot model to simulate each operation of the travel carriage SL and the robot MR, and thereby creates operation data (operation program, teaching program) for causing the travel carriage SL and the robot MR to operate in correspondence with an operation purpose. For example, in the case of welding a workpiece WK, the off-line teaching device TC causes the travel carriage SL and the robot MR to simulate welding of the workpiece WK, and thereby creates operation data for causing the travel carriage SL and the robot MR to actually weld the workpiece WK in accordance with the simulation result. Figure 2In the workpiece WK shown, six welding points Q1 to Q6 (an example of a plurality of work positions arranged in time series) are set, and five continuous welding lines connecting the welding points Q1 to Q6 in order are set, and the action data for welding is created using the welding points Q1 to Q6 and the welding lines. Note that if the position of the robot MR is determined, the position of the travel carriage SL is also determined, and thus the travel carriage model can be omitted. The action data created by the off-line teaching device TC is recorded (stored) in a recording medium (storage medium) that records (or stores) data, for example, and is read from the recording medium into the control device CL and stored in the control device CL. The recording medium (storage medium) is, for example, a floppy disk, a CD-R (Compact Disc Recordable), a DVD-R (Digital Versatile Disc Recordable), a USB (Universal Serial Bus) memory, an SD card (registered trademark), or the like. Note that the action data can also be transmitted from the off-line teaching device TC to the control device CL using data communication by connecting the off-line teaching device TC and the control device CL in a communicable manner, and stored in the control device CL.

[0055] The robot travel carriage position determination device D of the embodiment is equipped in the off-line teaching device TC as an example in the present embodiment.

[0056] The control device CL is a device for controlling the travel carriage SL and the robot MR to weld the workpiece WK using the welding torch WT in accordance with the action data (action program, teaching program) created by the teaching programmer TP and the off-line teaching device TC by teaching the travel carriage SL and the robot MR in advance.

[0057] The robot travel carriage position determination device D of the embodiment provided in the off-line teaching device TC has, for example, a control processing section 1, a storage section 2, an input section 3, a display section 4, and an interface section (IF section) 5 as shown. Figure 3

[0058] ​The input section 3 is a device connected to the control processing section 1 and inputting various instructions such as an instruction instructing start of teaching, and various data such as a name of motion data, interference range information, and the like required for operating the position decision device D (off-line teaching device TC), and is, for example, a plurality of input switches, a keyboard, a mouse, and the like assigned with a prescribed function. The display section 4 is a device connected to the control processing section 1 and displaying the instructions and data input from the input section 3 and a traveling stage model and a virtual robot model in a virtual space generated by the off-line teaching device TC (position decision device D) and the like in accordance with the control of the control processing section 1, and is, for example, a display device such as a CRT display, an LCD (liquid crystal display device), and an organic EL display.

[0059] Note that the input section 3 and the display section 4 can also be constituted by a touch panel. In the case of constituting the touch panel, the input section 3 is, for example, a position input device inputting by detecting an operation position in a resistive film method, an electrostatic capacity method, or the like. In the touch panel, a position input device is provided on a display surface of the display section 4, and a candidate of one or a plurality of input contents capable of being input to the display section 4 is displayed, and when a user touches a display position of an input content desired to be input, the position is detected by the position input device, and a display content displayed at the detected position is input to the position decision device D (off-line teaching device TC) as an operation input content of the user. In such a touch panel, the user easily intuitively understands an input operation, and thus a position decision device D (off-line teaching device TC) easy to handle for the user is provided.

[0060] The IF section 5 is a circuit connected to the control processing section 1 and inputting and outputting data between devices outside in accordance with the control of the control processing section 1, and is, for example, an interface circuit of RS-232C of a serial communication method, an interface circuit using a Bluetooth (registered trademark) specification, an interface circuit using a USB specification, and the like. In addition, the IF section 5 can also be, for example, a data communication card, a communication interface circuit of an IEEE 802.11 specification or the like, and a communication interface circuit transmitting and receiving a communication signal with a device outside.

[0061] The storage section 2 is a circuit connected to the control processing section 1 and storing various prescribed programs and various prescribed data in accordance with the control of the control processing section 1. Among the various prescribed programs, for example, there are included a control processing program, among which, for example, there are included a control program that controls each part 2 to 5 of the position determination device D (the off-line teaching device TC), an entry direction processing program that fixes the wrist center point of the robot MR in the posture of the tool (in this embodiment, the welding torch WT which is an example thereof) corresponding to a prescribed work position and obtains the direction of the arm of the robot MR as an arm entry direction in a manner not to overlap with the interference range, a position processing program that obtains the position of the travel car SL based on the arm entry direction obtained by the entry direction processing program, and the like. Among the various prescribed data, for example, there are included data necessary for executing the above-described programs, such as the interference range information. Such a storage section 2 is provided, for example, with a ROM (Read Only Memory) which is a nonvolatile storage element, an EEPROM (Electrically Erasable Programmable Read Only Memory) which is a rewritable nonvolatile storage element, and the like. Further, the storage section 2 includes a RAM (Random Access Memory) and the like which becomes a work memory of the control processing section 1 that stores data and the like generated in the execution of the prescribed programs. The storage section 2 can also be configured to be provided with a hard disk device having a larger storage capacity.

[0062] Further, the storage section 2 functionally includes an interference range information storage section 21 that stores the interference range information. The interference range information is information indicating an interference range in which the robot MR interferes in the prescribed surrounding environment. The interference range information is, for example, coordinates of a bending point of a contour line of the interference range in the case where the interference range is a polygon, and is coordinates of a center point of a sphere of the interference range and a radius in the case where the interference range is a sphere. More specifically, the interference range is a three-dimensional environmental model obtained by simulating obstacles such as a control panel and spare parts such as a rack, which are arranged in the surrounding environment of the robot MR, and the interference range information is information indicating the three-dimensional environmental model. Information indicating a second interference range in which the travel car SL interferes in the prescribed surrounding environment can also be included in the interference range information.

[0063] The control processing section 1 is a circuit for controlling each of the parts 2 to 5 of the position determining device D (off-line teaching device TC) in correspondence with the functions of the parts, respectively, reproducing the travel car SL and the robot MR as a virtual travel car model and a virtual robot model in a virtual space, causing these travel car model and virtual robot model to simulate each of the movements of the travel car SL and the robot MR, thereby generating movement data (movement program, teaching program) for causing the travel car SL and the robot MR to move in correspondence with a movement purpose, and at this time, finding the position of the travel car SL. The control processing section 1 is configured to have, for example, a CPU (Central Processing Unit) and its peripheral circuit. The control processing section 1 functionally has the control section 11, the entry direction processing section 12, and the position processing section 13 by executing a control processing program.

[0064] The control section 11 controls each of the parts 2 to 5 of the position determining device D (off-line teaching device TC) in correspondence with the functions of the parts, respectively, and is responsible for the overall control of the position determining device D (off-line teaching device TC).

[0065] The entry direction processing section 12 fixes the wrist rotation center point of the robot MR in the posture of the tool (welding torch WT in this embodiment) corresponding to the prescribed work position, and finds the direction of the arm of the robot MR as an arm entry direction in such a manner that it does not overlap with the interference range. The wrist rotation center point is a point at which the fourth rotation axis of the fourth joint J4, the fifth rotation axis of the fifth joint J5, and the sixth rotation axis of the sixth joint J6 intersect.

[0066] More specifically, the entry direction processing section 12 first decides (sets) the position and posture of the welding torch WT with respect to the prescribed welding point Q (an example of the prescribed work position) on the basis of construction information stored in advance in the storage section 2 as shown in Figure 4 The construction information is the welding conditions, the posture of the welding torch WT with respect to the groove of the welding line, and the like. Note that Figures 4 to 7 The travel car model and the virtual robot model in the virtual space are illustrated, but for the convenience of explanation, the reference numerals used in Figures 1 to 3 are directly used. The same applies to the Figure 9 described later. Also, since it is a virtual space, the travel car SL and the robot MR should be strictly called a travel car model and a virtual robot model, but including the above-described explanation using Figure 4 , they are directly called and described as the travel car SL and the robot MR. That is, in the above, the welding torch WT should be called and described as a welding torch model, but it is directly called and described as the welding torch WT.

[0067] Next, the entry direction processing unit 12 searches for an arm entry direction in the surrounding environment of the robot MR so as not to overlap with the interference range. Figure 5 As shown, an interference range AR represented by the interference range information stored in the interference range information storage unit 21 is set in the surrounding environment of the robot MR, and in a plane (for example, in a horizontal plane) including the wrist rotation center point RO at the position and posture of the welding torch WT set as described above, directions that do not overlap with the set interference range AR are explored circumferentially at prescribed angular intervals (for example, 5°, 10°, 15°, 20°, etc.) on the circumference of a circle centered on the wrist rotation center point RO as the center point, as the arm-entry direction. At this time, it is preferable to consider the size (thickness) of the arm of the robot MR. For example, the size (thickness) of the arm of the robot MR is considered by aligning the center line of the arm (third link LK3) of the robot MR with the arm-entry direction. Figure 5 In the example shown, the direction overlapping the interference area AR (solid line) is designated as evaluation point 0. The direction not overlapping the interference area AR on a directed line segment but overlapping the interference area AR when the arm size is considered (single-dotted dashed line) is designated as evaluation point 1. The direction not overlapping the interference area AR on a directed line segment and not overlapping the interference area AR when the arm size is considered (dashed line) is designated as evaluation point 2. In this embodiment, 18 directions serving as these evaluation points are searched for as possible arm entry directions.

[0068] Next, the entry direction processing unit 12 selects and determines one arm entry direction from the searched arm entry directions. Figure 5 In the example shown, any one of the 18 arm-entry directions can be set and determined, but one arm-entry direction is selected and determined from a plurality of arm-entry directions according to a prescribed criterion (rule, regulation, convention, standard) as the arm-entry direction. The prescribed criterion can be set appropriately, but is selected, for example, in a manner closest to the prescribed reference position RP. In the welding of this embodiment, the robot MR usually approaches (approaches) the welding point (an example of a working position) Q of the workpiece WK from a position on the front of the workpiece WK (front position), so in this embodiment, the prescribed reference position RP is the front position RP of the workpiece WK. Thus, in Figure 5 In the example shown, Figure 6 As shown in A, the entry direction processing unit 12 selects and determines an arm entry direction AD closest to the reference position RP from a plurality of arm entry directions as the arm entry direction AD. In this way, the arm entry direction AD of the arm of the robot MR observed from above is obtained. Figure 6In B of FIG. 10, a case is illustrated in which the robot MR (strictly speaking, a virtual robot model) is arranged (depicted) in such a manner that the arm of the robot MR is arranged along the arm approach direction AD thus determined.

[0069] Returning to Figure 3 The position processing section 13 determines the position of the travel carriage SL based on the arm approach direction AD determined by the approach direction processing section 12. As described above, if the position of the robot MR is determined, the position of the travel carriage SL is also determined, and therefore the position processing section 13 determines the position of the travel carriage SL by determining the position of the robot MR based on the arm approach direction AD determined by the approach direction processing section 12. The position of the robot MR based on the arm approach direction AD can be determined using a publicly known conventional method, for example, by determining the position of the robot MR using the method disclosed in the above-mentioned Patent Document 1, and determining the position of the travel carriage SL.

[0070] More specifically, the position processing section 13 sets an exploration plane that contains the arm approach direction AD determined by the approach direction processing section 12 and on which the robot origin O serving as the motion base point of the robot MR is located, sets the position of the travel carriage SL in such a manner that the robot origin O coincides with each of a plurality of lattice points set on the exploration plane, calculates the evaluation value of each of the lattice points at the position of the travel carriage SL, and determines the position of the travel carriage SL based on the evaluation values. Note that the evaluation value of each of the lattice points is calculated using the method disclosed in the above-mentioned Patent Document 1. Figure 4 The setting of the position and the posture of the welding torch WT described above corresponds to the initial setting step in the method disclosed in the above-mentioned Patent Document 1. The posture of the positioner PS is also set as disclosed in the above-mentioned Patent Document 1, but the posture of the positioner PS is appropriately set, and the description thereof is omitted. The same also applies to the following.

[0071] More specifically, the position processing section 13, for example, as described above, sets the position of the travel carriage SL in such a manner that the robot origin O coincides with each of a plurality of lattice points set on the exploration plane, and calculates the evaluation value of each of the lattice points at the position of the travel carriage SL. Figure 7As shown, the range of motion of the robot MR is found within a search plane that includes the arm approach direction AD found by the approach direction processing section 12 and passes through the robot origin O, which is the motion base point of the robot MR, and includes the front end of the robot MR (the front end of the welding torch WT, which is an example of a tool). Within the found range of motion, a plurality of grid points are discretely set. The robot origin O is located on the arm approach direction AD. The interval of the plurality of grid points is appropriately set in advance with a degree of fineness that is sufficient for the search. The position processing section 13 finds the position of the travel car SL for each of the plurality of grid points in such a manner that the grid point coincides with the robot origin O and finds a position candidate that is a position of the travel car SL within the range of motion of the travel car SL other than the interference range and that can perform an inverse transformation that determines the posture of the robot MR. The position processing section 13 finds an evaluation value for each of the grid points corresponding to the found position candidates. The evaluation value is found, for example, by an evaluation function that includes any one of the degree of margin with respect to the specific posture of the robot MR, the degree of margin with respect to the boundaries of the range of motion of each axis, the degree of interference or abnormal proximity with the surrounding environment or the workpiece WK in the posture of the robot MR, the degree of margin with respect to the boundaries of the range of motion of each axis of the travel car SL, the amount of movement from the last position of each axis of the travel car SL in the case where the work positions Qi are a plurality of work positions arranged in a time series. The position processing section 13 extracts the grid point that is equal to or higher than a prescribed threshold value set in advance and has the highest evaluation value (the highest evaluation value) from among the evaluation values of the grid points and determines the position candidate on the extracted grid point as the position of the travel car SL.

[0072] Figure 7 The xyz orthogonal coordinate system shown with the robot origin O as the coordinate origin is a local coordinate system for representing the position and posture of the arm with respect to the motion base point of the robot MR. When the position of the travel car SL (the position of the robot MR) is determined, the XYZ orthogonal coordinate system is correlated with the xyz orthogonal coordinate system.

[0073] Also, in the present embodiment, the robot travel car position determination device D is provided to the off-line teaching device TC, and therefore the position processing section 13 also adopts the position of the travel car SL as off-line teaching data (motion data, motion program, teaching program) of the robot MR.

[0074] Here, as Figure 2As in the example shown, in a case where a plurality of welding points (an example of work positions) Qi (in this example, i = 1 to 6) arranged in a time series exist, the entry direction processing section 12 calculates the arm entry direction ADi for each of the plurality of welding points Qi in the order of the time series, as described above, and the position processing section 13 calculates the position of the travel carriage SLi for each of the plurality of arm entry directions ADi calculated by the entry direction processing section 12, as described above. In this case, the entry direction processing section 12 calculates the arm entry direction ADi of this time in the order of the time series in such a manner that the arm entry direction ADi of the previous time ADi-1 is closest.

[0075] These control processing section 1, storage section 2, input section 3, display section 4, and IF section 5 can be constituted by a computer of a desktop type, a notebook type, or the like, for example. The computer constituting the above-described sections 1 to 5 is disposed in an operation room in a welding factory, for example, and can be assembled in a console (may be used as the console) or can be separated from the console.

[0076] Next, the operation of the present embodiment will be described. Figure 8 is a flowchart showing the operation of the robot travel carriage position determination device.

[0077] The robot travel carriage position determination device D (off-line teaching device TC) of such a configuration, when its power supply is turned on, performs initialization of each section required and starts its operation. In the control processing section 1, the control section 11, the entry direction processing section 12, and the position processing section 13 are functionally constituted by execution of the control processing program thereof.

[0078] In Figure 8 In the operation of the position of the travel carriage SL, the position determination device D (off-line teaching device TC) first determines the position and posture of the welding torch WT with respect to a prescribed welding point Q (an example of a prescribed work position) using the entry direction processing section 12 of the control processing section 1 (S1).

[0079] Next, the position determination device D explores an arm enterable direction in which the arm of the robot MR can enter in the surrounding environment of the robot MR without overlapping the interference range using the entry direction processing section 12 (S2).

[0080] Next, the position determination device D selects one arm enterable direction from the explored arm enterable directions according to a prescribed criterion using the entry direction processing section 12, and determines the arm entry direction AD (S3).

[0081] Then, the position determining device D uses the position processing section 13 of the control processing section 1 to find the position of the traveling stage car SL based on the arm approach direction AD found by the approach direction processing section 12 in the process S3, adopts the found position of the traveling stage car SL as the off-line teaching data (action data, action program, teaching program) of the robot MR (S4), and ends the present processing.

[0082] As shown in the example as shown in Figure 2 In the case where there are a plurality of welding points (one example of work positions) Qi arranged in time series, each of these processes S1 to S4 is executed for each welding point Qi.

[0083] As explained above, the robot traveling stage car position determining device D, the robot traveling stage car position determining method installed in the robot traveling stage car position determining device D, and the robot traveling stage car position determining program of the embodiment find the direction of the arm of the robot MR in a manner not to overlap with the interference range before finding the position of the robot traveling stage car SL, thus eliminating the situation where the process of finding the position of the robot traveling stage car SL is performed from the beginning again, and thus the position of the robot traveling stage car can be determined efficiently well.

[0084] The above robot traveling stage car position determining device D, robot traveling stage car position determining method, and robot traveling stage car position determining program perform the search in the circumferential direction of a circle with the wrist rotation center point RO as the center point in the plane including the wrist rotation center point RO, thus being able to search for the arm approach direction AD with a relatively simple process.

[0085] The above robot traveling stage car position determining device D, robot traveling stage car position determining method, and robot traveling stage car position determining program find the present arm approach direction ADi in a manner closest to the last arm approach direction ADi-1 in the order of time series in the case where there are a plurality of work positions (in the present embodiment, the welding points Qi which are one example thereof) arranged in time series, thus being able to find the position of the robot traveling stage car SL for each of the plurality of work positions arranged in time series so that the robot MR can move smoothly.

[0086] The robot travel vehicle position determination device D, the robot travel vehicle position determination method, and the robot travel vehicle position determination program described above set a search plane in which the robot origin O, which is the motion base point of the robot MR, is located on the arm approach direction AD that is calculated, set the position of the robot travel vehicle SL for each of a plurality of lattice points set in the search plane, calculated evaluation values for each of the lattice points, and calculated the position of the robot travel vehicle SL based on the evaluation values, and thus the appropriate position of the robot travel vehicle SL can be automatically and efficiently calculated.

[0087] Note that in the above-described embodiments, as shown in Figure 7 the wrist rotation center point RO is fixed and the third link LK3 is moved within the search plane, but in cases in which the third link LK3 cannot be moved or the range of movement of the third link LK3 is narrow (small), the position of the travel vehicle SL can also be searched for as follows.

[0088] Figure 9 is a diagram for explaining a case in which the robot origin is searched for in the circumferential direction of a circle centered on the position of the third joint of the robot within a search plane. Figure 9 With Figure 7Likewise, a view from the front direction of the robot MR is obtained. In this case, the position processing section 13 sets the position of the travel car SL in the search plane including the arm approach direction AD calculated by the approach direction processing section 12 in such a manner that the robot origin O coincides with each of a plurality of points set in the circumferential direction of a circle having the position of the third joint J3 as a center point, calculates the evaluation value of each of the points at the position of the travel car SL, and calculates the position of the travel car SL based on the evaluation values. More specifically, the position processing section 13 sets a circle having a distance from the position of the third joint J3 to the robot origin O (a distance determined in accordance with the length of the second link LK2) as a radius in the search plane including the arm approach direction AD calculated by the approach direction processing section 12 with the position of the third joint J3 as a center point, and sets a plurality of points on the circumference of the set circle. The position processing section 13 calculates the position of the travel car SL in such a manner that each of the points coincides with the robot origin O, and calculates the position of the travel car SL in the range of motion of the travel car SL other than the interference range and capable of performing the inverse transformation that determines the posture of the robot MR as a position candidate. The position processing section 13 calculates the evaluation value of each of the lattice points corresponding to the calculated position candidates. The evaluation value is as described above. The position processing section 13 extracts the point having the highest evaluation value (the highest evaluation value) that is equal to or higher than a predetermined threshold value set in advance from among the evaluation values of the lattice points, and determines the position candidate at the extracted point as the position of the travel car SL.

[0089] In order to embody the present application, the present application has been adequately and sufficiently described by the embodiments with reference to the accompanying drawings described above, but it should be recognized that the above-described embodiments can be easily changed and / or modified by those skilled in the art. Therefore, the change or modification by those skilled in the art is interpreted as included in the scope of the technical solution as long as it is not beyond the level of the claims recited in the technical solution.

Claims

1. A robot travel trolley position determination device for determining the position of a robot travel trolley, wherein the robot travel trolley carries a robot that performs a predetermined operation on a workpiece using a tool provided at its front end and moves. The robot travel vehicle position determination device comprises: an interference range information storage unit that stores interference range information indicating an interference range in a predetermined surrounding environment where the robot interferes; an entry direction processing unit that fixes the wrist rotation center point of the robot in the posture of the tool corresponding to a predetermined working position and obtains a direction of the robot arm as an arm entry direction so as not to overlap with the interference range; as well as a position processing unit that obtains the position of the robot travel vehicle based on the arm entry direction obtained by the entry direction processing unit; The position processing unit sets an exploration plane including the arm entry direction calculated by the entry direction processing unit, in which the robot origin serving as the movement base point of the robot is located in the arm entry direction, and sets the position of the robot traveling trolley in such a manner that the robot origin is respectively consistent with a plurality of grid points set in the exploration plane, calculates the evaluation value of each grid point at the position of the robot traveling trolley, and calculates the position of the robot traveling trolley based on the evaluation value.

2. The robot travel vehicle position determination device according to claim 1, wherein: The entry direction processing unit obtains the arm entry direction by searching in a plane including the wrist rotation center point in a circumferential direction of a circle having the wrist rotation center point as a center point.

3. The robot travel vehicle position determination device according to claim 1 or 2, wherein: The operation positions are multiple operation positions arranged along a time series. The entry direction processing unit obtains the arm entry direction for each of the plurality of work positions in the order of the time series. The position processing unit calculates the position of the robot travel vehicle for each of the plurality of arm entry directions calculated by the entry direction processing unit. The entry direction processing unit obtains the current arm entry direction in the order of the time series so as to be closest to the previous arm entry direction.

4. A method for determining the position of a robot traveling carriage, the method comprising determining the position of a robot traveling carriage that carries a robot that performs a predetermined operation on a workpiece using a tool provided at its front end, wherein: The method for determining the position of a robot traveling vehicle comprises: an interference range setting step of setting an interference range within a predetermined surrounding environment within which the robot interferes; an entry direction processing step of fixing a wrist rotation center point of the robot in a posture of the tool corresponding to a predetermined working position and obtaining a direction of the robot arm as an arm entry direction so as not to overlap with the interference range; as well as a position processing step of obtaining the position of the robot travel vehicle based on the arm entry direction obtained in the entry direction processing step; The position processing step sets an exploration plane including the arm entry direction obtained by the entry direction processing step, in which the robot origin serving as the movement base point of the robot is located in the arm entry direction. The position of the robot traveling trolley is set in such a manner that the robot origin is respectively consistent with a plurality of grid points set in the exploration plane, and the evaluation value of each grid point at the position of the robot traveling trolley is calculated, and the position of the robot traveling trolley is obtained based on the evaluation value.

5. A recording medium storing a robot travel trolley position determination program, wherein the robot travel trolley position determination program determines the position of a robot travel trolley that carries a robot that performs a predetermined operation on a workpiece using a tool provided at its front end, wherein: The robot vehicle position determination program is used to make the computer function as an interference range information storage unit, an entry direction processing unit, and a position processing unit. The interference range information storage unit stores interference range information indicating an interference range in which the robot interferes in a predetermined surrounding environment. The entry direction processing unit fixes the wrist rotation center point of the robot in the posture of the tool corresponding to the specified working position, and obtains the direction of the robot arm as the arm entry direction in a manner not overlapping with the interference range. The position processing unit obtains the position of the robot travel vehicle based on the arm entry direction obtained by the entry direction processing unit. The position processing unit sets an exploration plane including the arm entry direction calculated by the entry direction processing unit, in which the robot origin serving as the movement base point of the robot is located in the arm entry direction, and sets the position of the robot traveling trolley in such a manner that the robot origin is respectively consistent with a plurality of grid points set in the exploration plane, calculates the evaluation value of each grid point at the position of the robot traveling trolley, and calculates the position of the robot traveling trolley based on the evaluation value.

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