Linear member shape simulator for multi-joint robot, method thereof, and recording medium

Abstract

The present invention provides a linear member shape simulator, a method, and a program for a multi-joint robot that can obtain the shape of a linear member by an approximate curve even for a more complex shape. The linear member shape simulator (D) of the multi-joint robot according to the present invention inputs the positions of one or more passing points between the starting position and the ending position of the linear member, the initial positions of adjustment passing points for adjusting the length of the linear member, and adjustment parameters for the input adjustment passing points, uses the positions of the input passing points, and uses the initial positions of the input adjustment passing points as initial values, and repeatedly executes a shape process for obtaining the shape of the linear member and a length process for obtaining the length of the linear member under the obtained shape of the linear member until the difference between the actual length of the linear member and the obtained length of the linear member becomes equal to or less than an allowable value. Here, the adjustment parameters are changed when the shape process is executed.

Description

Technical Field

[0001] The present invention relates to a simulator for the shape of a linear member of a multi-joint robot, a method for simulating the shape of a linear member, and a program for simulating the shape of a linear member, which are configured to obtain the shape of a linear member attached to a multi-joint robot. Background Art

[0002] For example, multi-joint robots such as vertical six-axis robots are widely used in various industrial fields due to the development of their technology. The main multi-joint robots operate according to motion data (motion program, teaching program) of motions pre-taught according to the motion purpose. In the teaching method, since a motion program can be created without stopping the multi-joint robot during operation, the so-called off-line teaching method is mostly used. The off-line teaching method is a method in which an actual robot in the real space is reproduced as a virtual robot model in the virtual space of a computer, the virtual robot model is made to simulate the motion of the actual robot, thereby confirming the motion of the actual robot, and creating a motion program.

[0003] In such multi-joint robots, a tool corresponding to the use is sometimes attached to the arm tip, and linear members such as a cable for supplying power to the tool, a tube for supplying raw materials to the tool, or a wire material of the raw materials are appended. Therefore, in the off-line teaching method, it is also necessary to simulate the state of such a linear member, and such an off-line teaching method is disclosed in, for example, Patent Document 1 and Patent Document 2.

[0004] In the method for simulating a wire material disclosed in Patent Document 1, the coordinates of a plurality of fixed points that support a wire material attached to a robot, the tangent vector at the fixed point, and the length of the wire material between adjacent fixed points are identified, the coordinate positions of the fixed point and the tangent vector are converted based on the movement amount of the movable part of the robot, and the coefficients of a curve formula representing the shape of the wire material between the adjacent fixed points are calculated based on the values of the coordinate positions of the converted fixed point and the tangent vector and the length of the wire material between the adjacent fixed points, thereby predicting the deformation of the appended wire material due to following the motion of the robot.

[0005] The cable display device in the robot offline teaching system disclosed in the above-mentioned Patent Document 2 displays a robot having an arm and a hand attached to the front end of the arm on a screen, and operates the robot on the screen to teach the actions required for the robot. The robot offline teaching system includes: a cable state detection unit that detects the torsional state of the cable attached to the robot or the winding state of the cable around the arm; and a drawing unit that draws the cable state detected by the cable state detection unit on the screen. The cable state detection unit detects the torsional state or winding state of the cable based on the total rotation angle of the arm and / or the hand around the axis, and the installation angles of the respective fixed portions on the base end side and the front end side of the cable.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 07-182017

[0009] Patent Document 2: Japanese Patent Laid-Open No. 2004-074368

[0010] In addition, in the simulation method of a linear material disclosed in the above-mentioned Patent Document 1, the shape of the wire is approximated and displayed by a cubic curve based on the positions of two points and their tangent vectors. In the positions of these two points and their tangent vectors, it is difficult to represent complex shapes such as the winding of a cable with an approximate curve.

[0011] On the other hand, in the cable display device in the robot offline teaching system disclosed in the above-mentioned Patent Document 2, as described in its paragraph

[0023] and Figure 5 (b) etc., the drawing of the cable on the screen is performed by a collection of points (spheres) that are continuously circular around the upper arm. In such a collection of points, since it is impossible to determine in what shape the cable is wound around the arm, for example, it is difficult to intuitively correct the teaching action (action program) in consideration of the shape of the cable. Summary of the Invention

[0012] Problems to be Solved by the Invention

[0013] The present invention has been made in view of the above circumstances, and an object thereof is to provide a linear member shape simulator, a linear member shape simulation method, and a linear member shape simulation program for a multi-joint robot that can obtain the shape of a linear member with an approximate curve even for a more complex shape.

[0014] Means for Solving the Problems

[0015] The present inventors have conducted various studies and as a result, found that the above object is achieved by the present invention described below. That is, a wire member shape simulator for a multi-joint robot according to one aspect of the present invention obtains the shape of a wire member attached to the multi-joint robot in a multi-joint robot in a specified posture, wherein the wire member shape simulator for the multi-joint robot includes: an input unit that inputs, between a start position and an end position of the wire member, the positions of one or more passing points through which the wire member passes, the initial positions of adjustment passing points through which the wire member passes and that adjust the length of the wire member, and adjustment parameters for the adjustment passing points; a shape processing unit that performs shape processing for obtaining the shape of the wire member; a length processing unit that performs length processing for obtaining the length of the wire member in the shape of the wire member obtained by the shape processing unit; and a shape determination unit that repeatedly performs the shape processing and the length processing until the difference between the actual length of the wire member and the length of the wire member obtained by the length processing unit becomes equal to or less than an allowable value, using the positions of the passing points input by the input unit and using the initial positions of the adjustment passing points input by the input unit as initial values, and the shape determination unit changes the adjustment parameters when performing the shape processing.

[0016] Such a wire member shape simulator for a multi-joint robot can set one or more passing points through which the wire member passes between the start position and the end position of the wire member, and thus can represent a wire member having a more complex shape such as winding. Therefore, the above-described wire member shape simulator for a multi-joint robot can obtain the shape of the wire member by an approximate curve even for a more complex shape.

[0017] In another aspect, based on the above-described wire member shape simulator for a multi-joint robot, the adjustment parameter is the amount and direction of movement in one of the repetitions.

[0018] Such a wire member shape simulator for a multi-joint robot has the amount and direction of movement in one of the repetitions as an adjustment parameter, and thus can represent a wire member having a shape such as the flexure of a wire member that takes into account the tendency of the wire member. Therefore, the above-described wire member shape simulator for a multi-joint robot can obtain the shape of the wire member by an approximate curve, for example, taking into account the flexure caused by the tendency of the wire member.

[0019] In another aspect, based on these above-described wire member shape simulators for a multi-joint robot, the passing points include points where the wire member is wound around the arm of the multi-joint robot.

[0020] Accordingly, it is possible to provide a linear member shape simulator for a multi-joint robot that can obtain the shape of a linear member wound around the arm of the multi-joint robot by an approximate curve.

[0021] In another aspect, based on the above-described linear member shape simulator for a multi-joint robot, when the length of the linear member obtained by the length processing unit is longer than the actual length of the linear member, the shape determination unit changes the end position of the linear member. Preferably, based on the above-described linear member shape simulator for a multi-joint robot, the shape determination unit changes the end position of the linear member by a predetermined change amount within a predetermined range in a predetermined change direction.

[0022] Since such a linear member shape simulator for a multi-joint robot changes the end position of the linear member when performing shape processing, it is possible to obtain the shape of the linear member by an approximate curve while considering a device (implement) that adjusts the end position of the linear member, such as a tool balancer.

[0023] In another aspect, based on the above-described linear member shape simulator for a multi-joint robot, the shape processing unit obtains the shape of the linear member based on the start position, the vector at the start position, the end position, the vector at the end position, the position of the passing point, the vector at the position of the passing point, the position of the adjustment passing point, and the vector at the position of the adjustment passing point.

[0024] Such a linear member shape simulator for a multi-joint robot can obtain the shape of the linear member by an approximate curve while considering the rigidity of the linear member by adjusting the magnitude of the vector.

[0025] Another method for simulating the shape of a linear member of a multi-joint robot according to the present invention calculates the shape of the linear member attached to the multi-joint robot in a multi-joint robot in a specified posture. The method for simulating the shape of the linear member of the multi-joint robot includes: an input step in which, between the start position and the end position of the linear member, the positions of one or more passing points through which the linear member passes, the initial positions of the adjustment passing points through which the linear member passes and adjusts the length of the linear member, and the adjustment parameters of the adjustment passing points are input; a shape processing step in which the shape of the linear member is calculated; a length processing step in which the length of the linear member in the shape of the linear member calculated in the shape processing step is calculated; and a shape determination step in which, using the positions of the passing points input in the input step and using the initial positions of the adjustment passing points input in the input step as initial values, the shape processing step and the length processing step are repeatedly executed until the difference between the actual length of the linear member and the length of the linear member calculated in the length processing step becomes less than or equal to an allowable value. In the shape determination step, the adjustment parameters are changed when the shape processing is executed.

[0026] Another program for simulating the shape of a linear member of a multi-joint robot according to the present invention calculates the shape of the linear member attached to the multi-joint robot in a multi-joint robot in a specified posture. The program for simulating the shape of the linear member of the multi-joint robot causes a computer to execute: an input step in which, between the start position and the end position of the linear member, the positions of one or more passing points through which the linear member passes, the initial positions of the adjustment passing points through which the linear member passes and adjusts the length of the linear member, and the adjustment parameters of the adjustment passing points are input; a shape processing step in which the shape of the linear member is calculated; a length processing step in which the length of the linear member in the shape of the linear member calculated in the shape processing step is calculated; a shape determination step in which, using the positions of the passing points input in the input step and using the initial positions of the adjustment passing points input in the input step as initial values, the shape processing step and the length processing step are repeatedly executed until the difference between the actual length of the linear member and the length of the linear member calculated in the length processing step becomes less than or equal to an allowable value. In the shape determination step, the adjustment parameters are changed when the shape processing is executed.

[0027] The linear member shape simulation method for such a multi-joint robot and the program can set one or more passing points through which the linear member passes between the starting position and the ending position of the linear member, so that a linear member with a more complex shape such as winding can be represented. Therefore, the linear member shape simulation method for the multi-joint robot and the program can obtain the shape of the linear member by an approximate curve even for a more complex shape.

[0028] Advantages of the Invention

[0029] The linear member shape simulator, the linear member shape simulation method, and the linear member shape simulation program for the multi-joint robot according to the present invention can obtain the shape of the linear member by an approximate curve even for a more complex shape. Description of the Drawings

[0030] Figure 1 FIG. is a diagram for explaining the schematic structure of a welding system including a linear member shape simulator for a multi-joint robot according to an embodiment.

[0031] Figure 2 FIG. is a block diagram showing the structure of the linear member shape simulator for the multi-joint robot.

[0032] Figure 3 FIG. is a diagram for explaining each point in a guide cable as an example of a linear member.

[0033] Figure 4 FIG. is a diagram for explaining a case where passing points are set in such a way that a guide cable is wound around an arm as an example.

[0034] Figure 5 FIG. is a diagram for explaining the moving direction of an adjustment passing point considering the tendency of a guide cable.

[0035] Figure 6 FIG. is a flowchart showing the operation of the linear member shape simulator for the multi-joint robot.

[0036] Figure 7 FIG. is a diagram for explaining the simulation result in a modified mode.

[0037] Description of Reference Numerals:

[0038] TC Offline Teaching Device

[0039] D Linear Member Shape Simulator for Multi-Joint Robot

[0040] MR Multi-Joint Robot

[0041] 1 Control Processing Unit

[0042] 2 Input Unit

[0043] 3 Display unit

[0044] 5 Storage unit

[0045] 11 Control unit

[0046] 12 Shape processing unit

[0047] 13 Length processing unit

[0048] 14 Shape determination unit. Detailed implementation manners

[0049] Hereinafter, one or more embodiments of the present invention will be described with reference to the accompanying drawings. However, the scope of the present invention is not limited to the disclosed embodiments. It should be noted that structures with the same reference numerals in the respective drawings represent the same structures, and their descriptions are appropriately omitted. In this specification, in the case of general reference, the reference numerals with subscripts omitted are used, and in the case of referring to individual structures, the reference numerals with subscripts are used.

[0050] The wire-shaped member shape simulator of the multi-joint robot according to the embodiment is a device that obtains the shape of a wire-shaped member attached to the multi-joint robot in a specified posture. The wire-shaped member is a wire-shaped member that is long in one direction, and any member can be used as long as it can deform its shape. For example, it is a cable for supplying power to a tool installed at the front end of an arm according to a wire for use, a tube for supplying raw materials to the tool, or a wire material of the raw materials. The wire-shaped member shape simulator of the multi-joint robot includes: an input unit that inputs the positions of one or more passing points through which the wire-shaped member passes, the initial positions of adjustment passing points through which the wire-shaped member passes and adjusts the length of the wire-shaped member, and the adjustment parameters of the adjustment passing points between the start position and the end position of the wire-shaped member; a shape processing unit that performs shape processing to obtain the shape of the wire-shaped member; a length processing unit that performs length processing to obtain the length of the wire-shaped member in the shape of the wire-shaped member obtained by the shape processing unit; a shape determination unit that repeatedly performs the shape processing and the length processing until the difference between the actual length of the wire-shaped member and the length of the wire-shaped member obtained by the length processing unit becomes within an allowable value, using the positions of the passing points input by the input unit and using the initial positions of the adjustment passing points input by the input unit as initial values, and the shape determination unit changes the adjustment parameters when performing the shape processing. Hereinafter, the wire-shaped member shape simulator of such a multi-joint robot, the wire-shaped member shape simulation method and the wire-shaped member shape simulation program installed thereon will be described more specifically by taking the case of application to a welding system as an example. It should be noted that the wire-shaped member shape simulator, the method and the program of the multi-joint robot are not limited to application to the welding system, and can be applied to any system using a joint robot attached with the wire-shaped member.

[0051] Figure 1 FIG. is a diagram for explaining the schematic structure of a welding system including a wire-shaped member shape simulator of a multi-joint robot according to an embodiment. Figure 1 A in FIG. shows the overall structure, Figure 1 B in FIG. shows the case of including a moving device, Figure 1 C in FIG. shows the case where a wire feeding device WS is provided on the arm. Figure 2 FIG. is a block diagram showing the structure of the wire-shaped member shape simulator of the multi-joint robot. Figure 3 FIG. is a diagram for explaining each point in a guide cable as an example of a wire-shaped member. In Figure 3 FIG., the shape of the guide cable in the initial state before simulation is represented by a relatively long dashed line (---), and the shape of the guide cable after simulation is represented by a relatively short dashed line (···). Figure 4This is a diagram for explaining, as an example, the case where the passing point is set in such a way that the guiding cable is wound around the arm. Figure 5 This is a diagram for explaining the moving direction of the adjustment passing point considering the tendency of the guiding cable. Figure 5 A in it is a side view, Figure 5 B in it is a front view.

[0052] The welding system SY having the wire-shaped member shape simulator of the multi-joint robot in the embodiment is, for example, as shown in Figure 1 A in it, and includes a multi-joint robot MR, a control device CL, a teaching pendant TP, and an off-line teaching device TC.

[0053] The multi-joint robot MR is a robot having an arm AM with a plurality of joints that is connected to the control device CL and operates according to the control of the control device CL. For example, it is a vertical six-axis robot with six degrees of freedom having six first to sixth joints J1 to J6. At the wrist part WR at the front end of the arm AM, as an example of a tool, a welding torch WT is provided in this embodiment. The multi-joint robot MR can weld a workpiece WK by arc welding using a welding wire sent out from the welding torch WT. The guiding cable GC is a long tubular member (hollow member) in one direction that guides the welding wire. The welding wire is guided to the welding torch WT through the inside of the guiding cable GC and supplied to the welding torch WT. One end of the guiding cable GC is held and supported by a cable holding part CH at the wrist part WR. For example, as shown in Figure 1 C in it, the other end of the guiding cable GC can be provided at the upper part of the arm AM near the fourth joint J4 at the end opposite to the front end and is supported by a wire feeding device WS that supplies the welding wire. However, in this embodiment, for example, as shown in Figure 1 B in it, it is supported by a moving device MD arranged at a specified position above the multi-joint robot MR. The moving device MD is configured to include, for example, a tool balancer, and is a device that changes the position of the other end of the guiding cable GC by moving the other end of the guiding cable GC within a specified range in a specified moving direction, for example, the up and down direction (z direction). By lowering the other end of the guiding cable GC from a specified reference position (z0) to a position (z1) in the downward direction (-z direction), the position of the other end of the guiding cable GC is made closer to the arm AM of the multi-joint robot MR, thereby enabling the change of the movable area of the guiding cable GC. The guiding cable GC is an example of a wire-shaped member attached to the multi-joint robot.

[0054] The teach pendant TP is a handheld operating device that is connected to the control device CL and is used to manually operate the multi-joint robot MR. During the teaching of the movement of the multi-joint robot MR using the teach pendant TP, the multi-joint robot MR is actually moved by manual operation, thereby teaching the movement path, position, etc. of the welding torch WT relative to the workpiece WK.

[0055] The offline teaching device TC is a device that reproduces the multi-joint robot MR as a virtual robot model in the virtual space of a computer, and by simulating the movement of the virtual robot model to the multi-joint robot MR, action data (action program, teaching program) for making the multi-joint robot MR act according to the action purpose is produced. The action data produced by this offline teaching device TC is, for example, recorded (stored) in a recording (or storage) medium (storage medium) for recording (or storing) data, read from this 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, CD-R (Compact Disc Recordable), DVD-R (Digital Versatile Disc Recordable), USB (Universal Serial Bus) memory, SD card (registered trademark), etc. It should be noted that the action data can also be sent from the offline teaching device TC to the control device CL through data communication and stored in the control device CL by connecting the offline teaching device TC and the control device CL in a communicable manner.

[0056] In the present embodiment, as an example, the linear member shape simulator D of the multi-joint robot in the embodiment is provided in the offline teaching device TC.

[0057] The control device CL is a device that controls the multi-joint robot MR according to the action data (action program, teaching program) pre-taught to the multi-joint robot MR by the teach pendant TP and the offline teaching device TC, and welds the workpiece WK using the welding torch WT.

[0058] The linear member shape simulator D of the multi-joint robot in the embodiment included in the offline teaching device TC, for example, as Figure 2 shown, includes a control processing unit 1, an input unit 2, a display unit 3, an interface unit (IF unit) 4, and a storage unit 5.

[0059] The input unit 2 is a device that is connected to the control processing unit 1 and inputs various commands such as a command indicating the start of teaching, and various data required for operating the linear member shape simulator D (offline teaching device TC), such as the name of motion data, the presence or absence of the mobile device MD, etc., for example, it is a plurality of input switches, a keyboard, a mouse, etc. that are assigned specified functions.

[0060] In the present embodiment, for example, as Figure 3 shown, the position (starting point position) Ps of the starting point ps of the guide cable GC, which is an example of the linear member, in a specified first posture of the multi-joint robot MR, its starting point vector Vs, the position (ending point position) Pe of the ending point pe in the guide cable GC in the initial posture, its ending point vector Ve, and the actual length Lr of the guide cable GC are input to the input unit 2. The starting point vector Vs is a vector representing the tangent direction at the starting point position Ps on the curve showing the shape of the guide cable GC, and the ending point vector Ve is a vector representing the tangent direction at the ending point position Pe on the curve showing the shape of the guide cable GC.

[0061] Moreover, for example, as Figure 3 shown, the position (waypoint position) Pi of one or more waypoints pi through which the guide cable GC passes between the starting point position Ps of the starting point ps and the ending point position Pe of the ending point pe, the initial position of the adjustment waypoint q through which the guide cable GC passes and adjusts the length L of the guide cable GC (adjustment waypoint position), and the adjustment parameter of the adjustment waypoint (i = 1, 2, 3,...) are input to the input unit 2. It should be noted that in Figure 3 , Vi represents the vector (waypoint vector) at the waypoint pi, and U represents the vector (adjustment waypoint vector) at the adjustment waypoint q.

[0062] When setting the waypoint pi, for example, as Figure 4 shown, the waypoints p1 and p2 can be set in such a way that the guide cable GC is wound around the arm AM. Thus, a guide cable GC with a more complex shape such as winding can be represented. It should be noted that the winding of the guide cable GC around the arm AM does not necessarily need to wind around the arm AM for one full turn, and it can also wind less than one full turn. In Figure 4 the example shown, the guide cable GC winds around the arm AM for about half a turn.

[0063] The adjustment parameter passing through point q for adjustment is, for example, in the present embodiment, the amount of movement ΔM and the movement direction Um in one iteration of the shape processing and the length processing for obtaining the shape of the guide cable GC. The amount of movement ΔM in one iteration is preset to an appropriate value. The movement direction Um can be set arbitrarily, but is set by considering the tendency of the guide cable GC, and for example, a guide cable GC with a shape such as a flexure that takes into account the tendency can be represented. For example, as Figure 5 shown, when there is a tendency to bend in the upper right direction when looking down on the paper surface on the guide cable GC, a vector (tendency vector) Vh representing the direction of the bending tendency is set, and the movement direction Um is set in the direction of the resultant vector of the vector of its gravity (gravity vector) Vg.

[0064] The display unit 3 is a device that is connected to the control processing unit 1 and displays commands, data, and a virtual robot model (including the guide cable GC) in a virtual space generated by the offline teaching device TC (linear member shape simulator D) according to the control of the control processing unit 1. For example, it is a display device such as a CRT monitor, an LCD (liquid crystal display device), and an organic EL display.

[0065] It should be noted that the input unit 2 and the display unit 3 may also be constituted by a touch panel. In the case of constituting the touch panel, the input unit 2 is a position input device that detects and inputs an operation position in, for example, a resistive film method, a capacitance method, etc. In this touch panel, a position input device is provided on the display surface of the display unit 3, and one or more input content candidates that can be input are displayed in the display unit 3. When the user touches the display position where the input content to be input is displayed, the position is detected by the position input device, and the display content displayed at the detected position is input as the user's operation input content to the linear member shape simulator D (offline teaching device TC). In such a touch panel, the user can easily and intuitively understand the input operation, so a linear member shape simulator D (offline teaching device TC) that is easy for the user to operate is provided.

[0066] The IF unit 4 is a circuit that is connected to the control processing unit 1 and inputs and outputs data, for example, between the control processing unit 1 and an external device. For example, it is an interface circuit of RS-232C as a serial communication method, an interface circuit using the Bluetooth (registered trademark) standard, and an interface circuit using the USB standard. In addition, the IF unit 4 may also be, for example, a data communication card, a communication interface circuit that transmits and receives communication signals with an external device, such as a communication interface circuit according to the IEEE802.11 standard.

[0067] The storage unit 5 is a circuit connected to the control processing unit 1 and stores various specified programs and various specified data according to the control of the control processing unit 1. Among the various specified programs, for example, a control processing program is included. In the control processing program, for example, a control program for controlling each of the parts 2 to 5 of the linear member shape simulator D (offline teaching device TC), a shape processing program for performing shape processing to obtain the shape of the guide cable GC, which is an example of a linear member, a length processing program for performing length processing to obtain the length L of the guide cable GC under the shape of the guide cable GC obtained by the shape processing program, a shape determination program that uses the position Pi of the passing point pi input through the input unit 2 and uses the initial position Q of the adjustment passing point q input through the input unit 2 as an initial value and repeatedly executes the shape processing and the length processing until the difference between the actual length Lr of the guide cable GC and the length L of the guide cable GC obtained by the length processing program becomes within the allowable value, etc. Among the various specified data, for example, data such as the allowable value required when executing these respective programs is included. Such a storage unit 5 is, for example, a ROM (Read Only Memory) as a non-volatile storage element, an EEPROM (Electrically Erasable Programmable Read Only Memory) as a rewritable non-volatile storage element, etc. Moreover, the storage unit 5 includes a RAM (Random Access Memory), etc., which is a so-called working memory of the control processing unit 1 for storing data generated during the execution of the specified program. In addition, the storage unit 5 may be configured to include a hard disk device with a large storage capacity.

[0068] The control processing unit 1 is used to control each of the parts 2 to 5 of the linear member shape simulator D (offline teaching device TC) according to the functions of these respective parts, reproduce the multi-joint robot MR as a virtual robot model in a virtual space, and cause the virtual robot model to simulate the actions of the multi-joint robot MR, thereby generating action data (action program, teaching program) corresponding to the action purpose. At this time, it is a circuit for obtaining the shape of the guide cable GC, which is an example of a linear member attached to the multi-joint robot MR, in the multi-joint robot MR in a specified posture. The control processing unit 1 is configured, for example, to include a CPU (Central Processing Unit) and its peripheral circuits. The control processing unit 1 functionally includes a control unit 11, a shape processing unit 12, a length processing unit 13, and a shape determination unit 14 by executing a control processing program.

[0069] The control unit 11 controls each part 2 to 5 of the wire-shaped member shape simulator D (offline teaching device TC) according to the functions of the respective parts, and is responsible for the overall control of the wire-shaped member shape simulator D (offline teaching device TC).

[0070] The shape processing unit 12 performs shape processing to obtain the shape of the guide cable GC, which is an example of the wire-shaped member. More specifically, first, the shape processing unit 12 obtains the starting point position Ps, starting point vector Vs, ending point position Pe, and ending point vector Ve of the guide cable GC after movement when the multi-joint robot MR moves from the first posture to the next specified second posture based on the action data through so-called forward transformation processing. The forward transformation processing is generally a process of obtaining the positions and postures of the respective linkages and the position and posture of the front end of the multi-joint robot MR based on the joint values of the multi-joint robot MR, and uses well-known conventional means. Then, the shape processing unit 12 obtains the shape of the guide cable GC based on the starting point position Ps, starting point vector Vs, ending point position Pe, ending point vector Ve, passing point position Pi, passing point vector Vi, adjustment passing point position Q, and adjustment passing point vector U. More specifically, for example, the shape processing unit 12 obtains a spline curve that passes through each of the positions Ps, Pe, Pi, Q and the tangents at each of the positions Ps, Pe, Pi, Q are consistent with the directions of the respective vectors Vs, Ve, Vi, U as the shape of the guide cable GC.

[0071] In the xyz orthogonal coordinate system, when the parameters are set to t, x = f x (t), y = f y (t), z = f z (t) of the spline curve S i (t) is given by the following formula 1. The respective positions Ps, Pe, Pi, Q of the points ps, pe, pi, q through which the guide cable GC passes are given by the following formulas 2-1 to 2-3. When the unit vectors of the respective points ps, pe, pi, q are set to V i = (V xi , V yi , V zi ), and the weights of the respective unit vectors are set to wi, the boundary conditions of the spline curve are given by the following formula 3, and thus, the coefficients A i of the spline curve S i , B i , C i , D i are obtained. Here, Ws is the weight relative to the starting point ps, and We is the weight relative to the ending point pe. These wi weights will be described in detail in the deformation method described later, but here, they are preset to appropriate values.

[0072]

Formula 1

[0073]

[0074]

Formula 2

[0075]

[0076]

Formula 3

[0077]

[0078] The length processing unit 13 performs length processing for obtaining the length L of the guiding cable GC, which is an example of the linear member, in the shape obtained by the shape processing unit 12. The length L is obtained by the following formula 4.

[0079]

Formula 4

[0080]

[0081] The shape determination unit 14 uses the passing point position Pi of the passing point pi input by the input unit 2, and uses the initial position Q of the adjustment passing point q input by the input unit 2 as an initial value, and repeatedly performs the shape processing and the length processing until the difference between the actual length Lr of the guiding cable GC, which is an example of the linear member, and the length L of the guiding cable GC obtained by the length processing unit 13 becomes equal to or less than the allowable value Th. The allowable value Th is determined to be an appropriate value such as 7 [mm], 5 [mm], 3 [mm], etc. by considering the actual length Lr of the guiding cable GC, etc.

[0082] In the present embodiment, when the shape determination unit 14 performs the repeated shape processing for obtaining the shape of the guiding cable GC, the adjustment parameter is changed (updated). More specifically, the shape determination unit 14 changes the adjustment passing point position Q to a position moved by a one-time movement amount ΔM in the movement direction Um.

[0083] Moreover, in the present embodiment, when the shape determination unit 14 performs the shape processing, when the length L of the guiding cable GC obtained by the length processing unit 13 is longer than the actual length Lr of the guiding cable GC, the end point position pe of the guiding cable GC is changed by a prescribed change amount Δz within a prescribed range in a prescribed change direction. The prescribed change direction is a direction in which the position of the other end of the guiding cable GC can be moved by the moving device MD, and in Figure 1 the example shown in B of Figure 1In the example shown in B, it is the range from z0 to z1. The specified change amount Δz is, for example, in the present embodiment, the change amount Δz for one iteration in the repetition of the shape processing and the length processing for obtaining the shape of the guide cable GC. The change amount Δz for one iteration is preset to an appropriate value.

[0084] These control processing unit 1, input unit 2, display unit 3, IF unit 4, and storage unit 5 can be constituted by, for example, a desktop computer, a notebook computer, etc. The computers constituting these units 1 to 5 are, for example, arranged in the operation room in the welding factory, can be assembled in the console (can be used in combination with the console), or can also be separated from the console.

[0085] Next, the operation of the present embodiment will be described. Figure 6 It is a flowchart showing the operation of the linear member shape simulator of the multi-joint robot.

[0086] When the power of the linear member shape simulator D (offline teaching device TC) of the multi-joint robot with such a structure is turned on, initialization of necessary parts is executed, and its operation starts. In the control processing unit 1, by executing this control processing program, the control unit 11, shape processing unit 12, length processing unit 13, and shape determination unit 14 are functionally constituted.

[0087] In Figure 6 , regarding the shape determination of the linear member, the linear member shape simulator D (offline teaching device TC) first performs initial setting (S1). In this initial setting, the operator (user) inputs the starting point position Ps, starting point vector Vs, ending point position Pe, ending point vector Ve, actual length Lr of the guide cable GC, and the presence or absence of the moving device MD (in the example shown in B of Figure 1 it is present, and in the example shown in C of Figure 1 it is absent) from the input unit 2 in the guide cable GC in the first posture of the multi-joint robot MR. In the present embodiment, for example, the moving device MD is input. Thus, the linear member shape simulator D receives these inputs from the input unit 2 and stores these inputs in the storage unit 5. When there is a moving device MD, the operator also inputs the change direction (in the example shown in B of Figure 1 it is the -z direction), the change amount Δz for one iteration in the repetition for obtaining the shape of the guide cable GC, and its range (in the example shown in B of Figure 1 it is z0 to z1) from the input unit 2. Thus, the linear member shape simulator D receives these inputs from the input unit 2 and stores these inputs in the storage unit 5. It should be noted that the tolerance value Th can be input and stored in the processing S1 of this initial setting, or can also be stored in advance (can also be programmed in advance).

[0088] Next, the linear member shape simulator D obtains, through forward transformation processing, the starting point position Ps, starting point vector Vs, ending point position Pe, and ending point vector Ve (S2) of the guiding cable GC after movement when the multi-joint robot MR moves from the first posture to the next specified second posture by the shape processing unit 12 of the control processing unit 1 based on the action data.

[0089] Next, the linear member shape simulator D sets the passing points pi and q (S3). The operator inputs from the input unit 2 the passing point position Pi, passing point vector Vi, the initial position of the adjustment passing point position Q, the adjustment passing point vector U, the movement amount ΔM and movement direction Um for one time in the iteration for obtaining the shape of the guiding cable GC. Thereby, the linear member shape simulator D receives these inputs from the input unit 2 and stores these inputs in the storage unit 5.

[0090] As Figure 4 shown, when the guiding cable GC is wound around the arm AM, the passing point pi where the guiding cable GC is wound around the arm AM of the multi-joint robot MR is set, and the passing point position Pi is input. The movement direction Um can also be directly input, but in the present embodiment, as used Figure 5 as described above, it is indirectly input with the tendency vector Vh indicating the direction of the bending tendency of the guiding cable GC. The control processing unit 1 obtains the composite vector of the tendency vector Vh and the gravity vector Vg, and sets the direction of this composite vector as the movement direction Um.

[0091] Next, the linear member shape simulator D obtains the shape of the guiding cable GC (S4, shape processing) through the shape processing unit 12 based on the starting point position Ps, starting point vector Vs, ending point position Pe, ending point vector Ve, passing point position Pi, passing point vector Vi, adjustment passing point position Q, and adjustment passing point vector U. In the present embodiment, each coefficient Ai, Bi, Ci, Di is obtained through boundary conditions, and thereby the spline curve S i (t) representing the shape of the guiding cable GC is obtained.

[0092] Next, the linear member shape simulator D obtains the length L (S5, length processing) of the guiding cable GC in the shape obtained by the shape processing unit 12 through the length processing unit 13 of the control processing unit 1.

[0093] Next, the linear member shape simulator D determines, through the shape determination unit 14 of the control processing unit 1, whether the difference between the actual length Lr of the guide cable GC and the length L of the guide cable GC obtained by the length processing unit 13 in process S5 is equal to or less than the allowable value Th (S6). If the result of this determination is that the difference is not equal to or less than the allowable value Th (if the difference exceeds the allowable value Th, NO), the linear member shape simulator D then executes process S7. On the other hand, if the difference is equal to or less than the allowable value Th (YES), the linear member shape simulator D (offline teaching device TC) ends this process, and displays the guide cable GC on the virtual robot model in the virtual space displayed on the display unit 3 in the shape thus obtained.

[0094] In process S7, the linear member shape simulator D determines the presence or absence of the mobile device MD through the shape determination unit 14 of the control processing unit 1. If the result of this determination is that there is a mobile device MD (YES), the linear member shape simulator D then executes process S8. If the result of this determination is that there is no mobile device MD (NO), the linear member shape simulator D then executes process S9.

[0095] In this process S8, the linear member shape simulator D determines through the shape determination unit 14 whether length adjustment is required. More specifically, the shape determination unit 14 compares the actual length Lr in the guide cable GC with the length L of the guide cable GC obtained by the length processing unit 13 in process S5. If the result of this comparison is that the length L of the guide cable GC obtained by the length processing unit 13 in process S5 is longer than the actual length Lr in the guide cable GC, it is determined that adjustment is required (YES), and the linear member shape simulator D then executes process S10. On the other hand, if the result of this comparison is that the length L of the guide cable GC obtained by the length processing unit 13 in process S5 is not longer than the actual length Lr in the guide cable GC (if the length L of the guide cable GC obtained by the length processing unit 13 in process S5 is shorter than the actual length Lr in the guide cable GC), it is determined that adjustment is not required (NO), and the linear member shape simulator D then executes process S9.

[0096] In process S9, the linear member shape simulator D changes the position of the adjustment passing point Q to the position after moving by a one-time movement amount △M in the moving direction Um through the shape determination unit 14, and then executes process S4 (the process returns to process S4).

[0097] In process S10, the linear member shape simulator D changes the end point position pe of the guide cable GC to a one-time change amount △z in the change direction (in Figure 1the position moved in the -z direction (as shown in example B), and then process S4 is executed (the process returns to process S4).

[0098] It should be noted that when the number of repetitions for obtaining the shape of the guide cable GC reaches a preset specified number of times, the repetition can be forcibly terminated, and the content indicating that the shape of the guide cable GC cannot be determined can be displayed on the display unit 3. Through this display, the above-described Figure 6 each of the above-described processes, in process S3, the operator can set the passing point pi and the adjustment passing point q different from the previous time.

[0099] As described above, the linear member shape simulator D of the multi-joint robot, the linear member shape simulation method, and the linear member shape simulation program in the embodiment can set one or more passing points pi through which the linear member passes between the start position ps and the end position pe of the guide cable GC as an example of the linear member. Therefore, it is possible to represent a linear member having a more complex shape such as winding. Therefore, the linear member shape simulator D, the linear member shape simulation method, and the linear member shape simulation program of the above multi-joint robot can obtain the shape of the linear member by an approximate curve even for a more complex shape.

[0100] The linear member shape simulator D, the linear member shape simulation method, and the linear member shape simulation program of the above multi-joint robot have the movement amount △M and the movement direction Um in one of the repetitions as adjustment parameters. Therefore, it is possible to represent a linear member having a shape such as the flexure of a linear member considering the tendency of the linear member. Therefore, the linear member shape simulator D, the linear member shape simulation method, and the linear member shape simulation program of the above multi-joint robot can obtain the shape of the linear member by an approximate curve, for example, considering the flexure caused by the tendency of the linear member.

[0101] The linear member shape simulator D, the linear member shape simulation method, and the linear member shape simulation program of the above multi-joint robot change the end position pe of the guide cable GC as an example of the linear member when performing the shape process. Therefore, it is possible to obtain the shape of the linear member by an approximate curve in consideration of a device (implement) for adjusting the end position pe of the guide cable GC, such as a tool balancer.

[0102] According to the present embodiment, it is possible to provide a linear member shape simulator D, a linear member shape simulation method, and a linear member shape simulation program of a multi-joint robot that can obtain the shape of a linear member wound around the arm AM of the multi-joint robot MR by an approximate curve.

[0103] It should be noted that in the above-described embodiment, the shape processing unit 12 obtains the shape of the linear member based on the starting point position Ps, the vector Vs at the starting point position Ps, the ending point position Pe, the vector Ve at the ending point position Pe, the position Pi of the passing point pi, the vector Vi at the position Pi of the passing point pi, the position Q of the adjustment passing point q, and the vector U at the position Q of the adjustment passing point q. Thus, by adjusting the magnitudes of the vectors, the shape of the linear member can be obtained by an approximate curve while considering the rigidity of the linear member.

[0104] More specifically, in the above example, the shape of the linear member is obtained by Equations 1 to 3, and by adjusting the weights wi of the respective vectors in Equation 3, the rigidity of the linear member can be expressed. In Figure 7 An example of the simulation results with the weights Ws and We for the starting point ps and the ending point pe adjusted is shown.

[0105] Figure 7 It is a diagram for explaining the simulation results in the deformation mode. Figure 7 A in Figure 7 represents the result when Ws = We = 1, Figure 7 B in Figure 7 represents the result when Ws = We = 2, Figure 7 C in

[0106] Comparing Figure 7 A to Figure 7 C in the respective diagrams, it can be seen that as the weights Ws and We for the starting point ps and the ending point pe increase, the guiding cable GC is difficult to bend from the directions of the respective vectors Vs and Ve at the starting point ps and the ending point pe. Therefore, the rigidity of the starting and ending ends of the guiding cable GC can be expressed by the weights Ws and We for the starting point ps and the ending point pe.

[0107] In addition, by adjusting the weights wi of the respective vectors at the passing point pi and the adjustment passing point q set when the guiding cable GC showing a more complex shape such as winding is expressed, the rigidity of the guiding cable GC other than the starting and ending ends can be expressed.

[0108] In order to describe the present invention, the present invention has been appropriately and fully described with reference to the accompanying drawings and through embodiments in the above content. However, those skilled in the art should recognize that it is easy to make changes and / or improvements to the above-described embodiments. Therefore, as long as the changes or improvements implemented by those skilled in the art are not beyond the scope of the technical solution described in the technical solution, such changes or improvements are interpreted as being included in the scope of the technical solution of the technical solution.

Claims

1. A linear member shape simulator for a multi-joint robot, which obtains the shape of a linear member attached to the multi-joint robot in a multi-joint robot in a specified posture, wherein, The linear member shape simulator of the multi-joint robot includes: An input unit that inputs the starting position of the linear member, a starting vector indicating the tangent direction at the starting position in a curve showing the shape of the linear member, the ending position of the linear member, an ending vector indicating the tangent direction at the ending position in a curve showing the shape of the linear member, the positions of one or more passing points through which the linear member passes between the starting position and the ending position, a passing point vector indicating the tangent direction at the passing point in a curve showing the shape of the linear member, the initial position of an adjustment passing point through which the linear member passes and adjusts the length of the linear member, an adjustment passing point vector indicating the tangent direction at the adjustment passing point in a curve showing the shape of the linear member, and an adjustment parameter of the adjustment passing point; A shape processing unit that performs shape processing to obtain the shape of the linear member based on the starting position, the starting vector, the ending position, the ending vector, the positions of the passing points, the passing point vectors, the positions of the adjustment passing points, and the adjustment passing point vectors; A length processing unit that performs length processing to obtain the length of the linear member in the shape of the linear member obtained by the shape processing unit; And A shape determination unit that uses the positions of the passing points input by the input unit and uses the initial position of the adjustment passing point input by the input unit as an initial value, and repeatedly performs the shape processing and the length processing until the difference between the actual length of the linear member and the length of the linear member obtained by the length processing unit becomes less than or equal to an allowable value. At least one of the one or more passing points is set such that the linear member is wound around the arm of the multi-joint robot. The adjustment parameter is a one-time movement amount and a movement direction when repeatedly performing the shape processing and the length processing for moving the adjustment passing point. When performing the shape processing, the shape determination unit changes the position of the adjustment passing point to a position moved by the one-time movement amount of the adjustment parameter in the movement direction of the adjustment parameter.

2. The linear member shape simulator for a multi-joint robot according to claim 1, wherein, When the length of the linear member obtained by the length processing unit is longer than the actual length of the linear member, the shape determination unit changes the ending position of the linear member.

3. A linear member shape simulation method for a multi-joint robot, which obtains the shape of a linear member attached to the multi-joint robot in a multi-joint robot in a specified posture, wherein, The linear member shape simulation method for the multi-joint robot includes: An input process, in which the starting position of the linear member, a starting vector representing the tangent direction at the starting position in the curve showing the shape of the linear member, the ending position of the linear member, an ending vector representing the tangent direction at the ending position in the curve showing the shape of the linear member, the positions of one or more passing points through which the linear member passes between the starting position and the ending position, a passing point vector representing the tangent direction at the passing point in the curve showing the shape of the linear member, the initial position of an adjustment passing point through which the linear member passes and adjusts the length of the linear member, an adjustment passing point vector representing the tangent direction at the adjustment passing point in the curve showing the shape of the linear member, and an adjustment parameter of the adjustment passing point are input; A shape processing process, in which the shape of the linear member is obtained based on the starting position, the starting vector, the ending position, the ending vector, the positions of the passing points, the passing point vectors, the position of the adjustment passing point, and the adjustment passing point vector; A length processing process, in which the length of the linear member in the shape of the linear member obtained in the shape processing process is obtained; and A shape determination process, in which the shape processing process and the length processing process are repeatedly executed until the difference between the actual length of the linear member and the length of the linear member obtained in the length processing process becomes equal to or less than an allowable value, using the positions of the passing points input in the input process and using the initial position of the adjustment passing point input in the input process as an initial value; At least one of the one or more passing points is set such that the linear member is wound around the arm of the multi-joint robot; The adjustment parameter is a one-time movement amount and a movement direction when repeatedly executing the shape processing process and the length processing process for moving the adjustment passing point; In the shape determination process, when executing the shape processing process, the position of the adjustment passing point is changed to a position moved by the one-time movement amount of the adjustment parameter in the movement direction of the adjustment parameter.

4. A recording medium that stores a linear member shape simulation program for a multi-joint robot, where the linear member shape simulation program for the multi-joint robot obtains the shape of a linear member attached to the multi-joint robot in a multi-joint robot in a specified posture, and The linear member shape simulation program for the multi-joint robot causes a computer to execute: Input process, in which the starting position of the linear member, the starting vector representing the tangent direction at the starting position in the curve showing the shape of the linear member, the ending position of the linear member, the ending vector representing the tangent direction at the ending position in the curve showing the shape of the linear member, the positions of one or more passing points through which the linear member passes between the starting position and the ending position, the passing point vectors representing the tangent directions at the passing points in the curve showing the shape of the linear member, the initial position of the adjustment passing point through which the linear member passes and adjusts the length of the linear member, the adjustment passing point vectors representing the tangent directions at the adjustment passing point in the curve showing the shape of the linear member, and the adjustment parameters of the adjustment passing point are input; Shape processing process, in which the shape of the linear member is obtained based on the starting position, the starting vector, the ending position, the ending vector, the positions of the passing points, the passing point vectors, the position of the adjustment passing point, and the adjustment passing point vectors; Length processing process, in which the length of the linear member in the shape of the linear member obtained in the shape processing process is obtained; Shape determination process, in which, using the positions of the passing points input in the input process and using the initial position of the adjustment passing point input in the input process as the initial value, the shape processing process and the length processing process are repeatedly executed until the difference between the actual length of the linear member and the length of the linear member obtained in the length processing process becomes within the allowable value; At least one of the one or more passing points is set such that the linear member is wound around the arm of the multi-joint robot; The adjustment parameter is the amount of movement and the direction of movement per iteration when the adjustment passing point is moved and the shape processing process and the length processing process are repeatedly executed; In the shape determination process, when the shape processing process is executed, the position of the adjustment passing point is changed to the position after moving by the amount of movement per iteration of the adjustment parameter in the direction of movement of the adjustment parameter.

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