JP2008130022A - Industrial robot control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an industrial robot control device capable of performing uniform processing of a side face and a roll face of a work and easily teaching a program that performs the operation by performing processing in one spiral shape such as one-stoke drawing when performing processing such as build up welding to the side face and the roll face of the work. <P>SOLUTION: Teaching data or the like of a start point Ps and an end point Pe input by performing a manual operation of a manipulator and a positioner for a spiral build up operation are stored in an auxiliary storage device. A CPU of the robot control device performs an interpolation operation on the basis of a moving velocity V, a spiral pitch Pi or the like of a TCP of a spiral instruction and calculates an interpolation point position (posture) on a spiral trace of the taught start point Ps to end point Pe by Xn=Rs*cos(θn), Yn=Rs*sin(θn), and Zn=θn*κ. The CPU calculates an operation amount of the manipulator in each axis value on the basis of each position posture of each interpolation point of the calculated spiral trace and controls the manipulator and the positioner. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an industrial robot control apparatus.

   In build-up welding work using a robot, in order to obtain stable and highly accurate welding quality, it is possible to teach that the workpiece is moved by a positioner or an external positioning shaft to perform downward welding (Patent Document 1).

Further, since the build-up welding operation using the robot is welding in which the torch is moved so as to trace the surface, the program for building up the entire surface needs to teach a large number of positions. Therefore, as an efficient teaching method, a method of teaching a program for overlay welding a part of a surface and extending the entire surface based on the program has been used. For example, in the case of circumferential overlay welding, a plurality of circumferential welding programs having different radii by pitches are created, and welding is performed by continuously executing these programs (Patent Document 2).
JP-A-11-129070 Japanese Patent Laid-Open No. 2001-300726

  By the way, in the conventional teaching of overlay welding work, when overlay welding is performed in a spiral shape, one work pattern is enlarged / reduced or shifted to create a plurality of patterns, which are combined to form a whole. A technique of working in a spiral shape is used. In this method, it is necessary to connect the patterns, and the weld bead does not have a uniform thickness at the connecting portion. For example, in the case of circumferential welding that creates multiple circumferential welding programs with different radii by different pitches and executes them continuously, wrap the weld section because it is necessary to connect beads at the welding start / end points of each circumferential welding. There is a need, and the lap part and the surrounding bead will be uneven. For this reason, in the subsequent process, a processing operation is required to eliminate these irregularities and make them uniform.

  Also, when a general-purpose industrial robot is used to continuously apply a spiral to the workpiece surface, one work pattern can be enlarged, reduced, or shifted in the same manner as overlay welding. A technique is used in which a plurality of patterns are created and combined to work as a whole. For this reason, when the coating is performed in a spiral shape, a connecting portion is required in the same manner. For this reason, the thickness of the coating film at the connecting portion increases, and the thickness of the coating film other than at the connecting portion becomes non-uniform. There's a problem.

  The object of the present invention is to perform uniform processing on a side surface or a roll surface of a workpiece by performing processing such as overlay welding on a side surface or a roll surface of a workpiece in a single spiral shape like a single stroke. Another object of the present invention is to provide an industrial robot control apparatus that can perform simple processing and can easily teach a program for executing the work.

  In order to solve the above-described problems, the invention of claim 1 is an industry that performs cooperative work by controlling a work rotating means for rotating a work and a manipulator having a work means for performing work on the work. In the robot controller for teaching, the work rotating means and the manipulator are moved to teach the spiral operation section of the working means, the teaching means for teaching the parameters of the spiral command, and the storage for storing the spiral operation section and the parameters The gist of the present invention is an industrial robot control apparatus comprising: a means; and an arithmetic means for generating a spiral trajectory of the working means in a spiral motion section by performing an interpolation calculation based on the parameter.

The invention of claim 2 is characterized in that, in claim 1, the parameters of the spiral command include a moving speed and a spiral pitch of the working means.
According to a third aspect of the present invention, in the second aspect, the workpiece has a roll surface having a constant diameter in the spiral operation section, and the calculation unit generates a spiral locus with respect to the roll surface. A helical trajectory of the working means in a spiral motion section is generated by performing an interpolation calculation based on the diameter and the parameter.

  According to a fourth aspect of the present invention, the workpiece according to the second aspect of the present invention is configured such that the roll surface is formed in a conical surface in the spiral operation section, and the calculation unit generates a spiral locus with respect to the roll surface. A helical trajectory of the working means in the spiral motion section is generated by performing interpolation calculation based on the diameters at the start point and end point in the spiral motion section and the parameters.

  According to a fifth aspect of the present invention, in the second aspect, the work has an end face that is orthogonal to a rotation center axis of the work rotating means and has a flat surface in a spiral operation section, and the computing means is arranged with respect to the end face. Generating a spiral trajectory of the working means in the spiral motion section by performing an interpolation operation based on either the diameter at the start point or the end point in the spiral motion section and the parameter so as to generate a spiral trajectory And

  According to invention of Claim 1, when processing, such as overlay welding, is performed with respect to the side surface or roll surface of a workpiece, the processing can be performed in one spiral shape like a one-stroke drawing. It is possible to perform uniform processing on the side surface and roll surface of the machine and to easily teach a program for executing the work. In addition, since the teaching of the present invention is simple, work preparation time can be greatly shortened.

According to the second aspect of the present invention, it is possible to easily generate the spiral trajectory of the working means in the spiral motion section by performing the interpolation calculation based on the moving speed and the helical pitch of the working means.
According to the invention of claim 3, when processing such as build-up welding is performed on a workpiece having a roll surface having a constant diameter in the spiral operation section, the processing is performed in a single spiral shape like a single stroke. As a result, uniform processing can be performed on the roll surface of the work, and a program for executing the work can be easily taught.

  According to the invention of claim 4, when processing such as build-up welding is performed on a work whose roll surface is formed into a conical surface in the spiral operation section, it is in a single spiral shape like a single stroke. Processing can be performed, and as a result, uniform processing can be performed on the roll surface of the workpiece, and a program for executing the operation can be easily taught.

  According to the invention of claim 5, when processing such as build-up welding is performed on a workpiece having an end surface that is orthogonal to the rotation center axis of the workpiece rotating means and has a flat surface in the spiral operation section, Thus, the processing can be performed in a single spiral shape, uniform processing can be performed on the side surface (that is, the end surface) of the workpiece, and a program for executing the operation can be easily taught.

(First embodiment)
Hereinafter, a first embodiment in which the industrial robot control device of the present invention is embodied in a robot control device 30 that performs overlay welding will be described with reference to FIGS.

  FIG. 1 shows an industrial robot control system used in this embodiment. The industrial robot control system is provided with a manipulator 10, a positioner 20, a robot control device 30 for controlling the manipulator 10 and the positioner 20, and a welding power supply device 40 for outputting a welding voltage to pass a welding current. Yes.

  The manipulator 10 includes a plurality of arms and is driven via joints that connect the arms. The manipulator 10 of the present embodiment has 6 degrees of freedom, but is not limited to 6 degrees of freedom, and may have a plurality of degrees of freedom other than 6 degrees of freedom. A torch 11 as a working means (that is, a tool) is attached to the tip of the tip arm of the manipulator 10, and arc welding (welding) is performed on the workpiece W (workpiece) using the torch 11. The positioner 20 of the present embodiment has a swivel shaft (not shown) that can be driven to rotate while supporting a cylindrical workpiece W parallel to the installation surface of the positioner 20, that is, horizontally. The pivot axis is driven by a servo motor (not shown). Then, the positioner 20 faces the torch 11 of the manipulator 10 and rotates the workpiece W so that the workpiece is suitable for welding by the torch 11.

  As shown in FIG. 2, the robot control device 30 includes a CPU (central processing unit) 31 that serves as a control center of the robot control device 30 and a RAM 32 that functions as buffers for teaching programs that define the operations and operations of the manipulator 10. A ROM 33 for storing various control programs is provided. Further, the robot control device 30 is connected to the auxiliary storage device 35 including a memory for storing a teaching program taught by manual control with respect to the manipulator 10 and the positioner 20, and the TP 36. A teaching pendant I / F (interface) 34 is provided. The TP 36 includes a display device 36a that is operated by an operator when manual control of the manipulator 10 and displays predetermined operation information, and a keyboard 36b used for inputting predetermined data. The TP 36 is used as teaching means for teaching the manipulator 10 the teaching program. The auxiliary storage device 35 corresponds to storage means for storing teaching data including a spiral operation section, various parameters of a spiral command, and a teaching program.

  Further, the robot control device 30 includes a servo driver I / F 38. The servo driver I / F 38 is connected to the plurality of servo drivers (servo mechanisms) 38a that drive each joint of the manipulator 10. The servo drivers 38a are connected to servo motors 13a to 13f provided at the joints in a state that can be controlled by the servo drivers 38a. Further, the manipulator 10 and the positioner 20 can be operated by the TP 36.

  The CPU 31, RAM 32, ROM 33, teaching pendant I / F 34, auxiliary storage device 35, TP 36, and servo driver I / F 38 described above are connected to each other via a bus (BUS) 39.

Now, the operation of the industrial robot control system configured as described above will be described. FIG. 3 is a flowchart for program editing.
First, in S10, the operator manually operates the manipulator 10 and the positioner 20 for the spiral build-up operation using the keyboard 36b of the TP 36, and provides the teaching data and welding conditions of the start point Ps and the end point Pe. Input (see FIG. 5). Here, the welding conditions include welding speed (that is, TCP moving speed V), spiral pitch Pi, spiral rotation direction, welding current, welding voltage, and the like.

  In S12, the CPU 31 edits the teaching data and welding conditions input in S10 into a teaching program for spiral overlaying and stores it in the auxiliary storage device 35, and ends this program editing process.

  Here, in the stored teaching program, the command for overlaying is represented by the name Spiral. The teaching program of the present embodiment is for performing overlay welding in a spiral manner on the roll surface Wr of the cylindrical workpiece W having the same diameter in the spiral operation section from the start point Ps to the end point Pe. It is. Here, the spiral operation section in the first embodiment is a range between the start point Ps and the end point Pe on the roll surface Wr.

The spiral instruction (that is, the spiral instruction) is described as follows, for example.
Spiral Vel Pb pi Dir
Note that Vel is the moving speed (welding speed) of TCP, and Pb is the position and orientation of the torch 11 at the target point (end point) (that is, the end point Pe). Pi represents the helical pitch (mm) (see FIG. 5). Dir indicates the direction of rotation of the spiral, + is the right-handed screw direction, and-is the left-handed screw direction.

  In the spiral command, the TCP trajectory spirals in the specified rotation direction with the rotation axis of the positioner 20 as the spiral center axis at the specified pitch from the start point (position taught immediately before the spiral command) to the target position (end point). It is an instruction to do. The spiral pitch Pi is designated based on the bead width determined by the welding conditions. Here, the spiral pitch Pi is set in such an amount that enables overlaying to uniformly cover the roll surface Wr of the workpiece W with beads, but is not limited to this value. Further, while the torch 11 moves from the start point Ps to the end point Pe by the Spiral command, the roll is at least as many times as (number of quotients) obtained by integerizing (distance between Pe-Ps) / (spiral pitch Pi). It means turning.

Here, the moving speed V (welding speed) of the TCP and the helical pitch Pi correspond to parameters of the helical command.
Next, the build-up (spiral) operation (program reproduction) in the industrial robot control system will be described. FIG. 4 is a flowchart of the teaching program reproduction that is read out by the CPU 31 of the robot controller 30 after the teaching program is read out.

  When the operator designates the teaching program including the Spiral instruction by TP 36 and inputs an activation signal, the CPU 31 of the robot control device 30 reads the teaching program from the auxiliary storage device 35 in S20. Subsequently, the CPU 31 interprets the Spiral instruction (instruction set) of the teaching program in S22, and sequentially executes the recorded instructions in S24 to S30.

  In S24, when the CPU 31 reads the Spiral instruction, the CPU 31 performs an operation so that the torch 11 draws a spiral locus based on the parameter of the Spiral instruction. Here, the calculation of the spiral trajectory in S24 is performed as follows.

  The information on the spiral center axis (the direction cosine of the spiral center axis, the spiral center position) is the turning axis (that is, the rotation center axis) of the positioner 20. Here, if the swivel axis (rotation center axis) of the positioner 20 is the Z axis of the work coordinates, the direction cosine is (0, 0, 1) and the spiral center position is (0, 0, 0) in the work coordinates. (See FIG. 5).

Therefore, the interpolation point position (posture) on the spiral locus is calculated as follows.
As shown in FIG. 6B, the distance (ΔS) between the interpolation points Pn−1 and Pn is
△ S = V ・ △ t
Where Δt: interpolation pitch (sec) V: movement speed (welding speed)
It is.

Assuming that the rotation angle around the spiral central axis per interpolation is Δθ, the axial translation distance ΔHn between the interpolation points is ΔHn = Pi · Δθ / (2π) = κ · Δθ (1)
However, κ = Pi / (2π).

Further, the moving distance ΔLn in the arc direction is Rs when the radius of the roll surface Wr of the work W is Rs (see FIG. 6A).
ΔLn = Rs · Δθ (2)
It becomes. Here, since ΔLn and Δθ are very small, the curvature of the curved surface (roll surface Wr) may be ignored.
ΔS ² = ΔHn ² + ΔLn ² (3)
It becomes.

The position of the interpolation point Pn is calculated from the spiral equation: Xn = Rs · cos (θn) (4)
Yn = Rs · sin (θn) (5)
Zn = θn · κ (6)
Ask for.

Here, θn in the above formulas (4) to (6) is obtained as follows.
Substituting Equations (1) and (2) into Equation (3) to obtain Δθ yields Δθ = ΔS / √ (κ ² + Rs ² ).

Therefore, θn is
θ1 == ΔS / √ (κ ² + Rs ² ) (7)
θ2 = θ1 + ΔS / √ (κ ² + Rs ² ) (8)
θ3 = θ2 + ΔS / √ (κ ² + Rs ² ) (9)
………
θn = θn−1 + ΔS / √ (κ ² + Rs ² )
= N · ΔS / √ (κ ² + Rs ² ) (10)
It is assumed that the torch posture of the interpolation point Pn is equally interpolated between the start point / end point and the torch posture with respect to the floor according to the progress rate of θ. If a downward torch posture is taught, the torch 11 keeps that posture and draws a spiral trajectory.

In this way, each interpolation point at the work coordinates of the torch 11 is determined in S24. That is, the CPU 31 calculates a spiral trajectory.
In S26, the CPU 31 performs processing at the target point (that is, the end point). That is, when the distance L between the start point Ps and the end point Pe of the spiral motion does not coincide with an integral multiple of the spiral pitch Pi (that is, when the remainder is obtained by dividing the distance L by the spiral pitch Pi), the CPU 31 The (remainder part) is set to advance to the target point on the circumference.

  In this embodiment, if the Zn exceeds the Z-axis coordinate of the end point Pe in the interpolation calculation before reaching the end point Pe (target point), the value of Zn is the same as the Z-axis coordinate of the end point Pe. After that, the interpolation calculation of only Xn and Yn is performed. FIG. 7 shows an example in which, after reaching the same Z-axis coordinate as the end point (target point) at Pm, the robot moves on the circumference passing through Pm and the end point (target point). It is shown.

The spiral trajectory composed of the interpolation points from the start point Ps to the end point Pe calculated in S24 and S26 is temporarily stored in the RAM 32.
In S <b> 28, the CPU 31 inversely transforms each position and orientation for each interpolation point of the torch 11 and the positioner 20 in the workpiece coordinates, and obtains the axis values of the manipulator 10 and the positioner 20. Each axis value is the position (angle) of the joint drive shaft (not shown) of the manipulator 10 and the turning axis (that is, the rotation center axis) of the positioner 20 of the manipulator 10.

  In S30, the CPU 31 obtains an operation amount for each interpolation of each axis based on each axis value calculated in S28, and outputs a command to the manipulator 10 and the servomotors 13a to 13f of the positioner 20, and the like. Further, the CPU 31 converts the welding condition into a command value for the welding power source device 40 and outputs the command value to the welding power source device 40.

  Based on the command value, the welding power supply device 40 performs wire feeding according to the welding conditions and outputs a welding current and a welding voltage from the start point to the end point taught in the teaching program.

  In addition, the torch 11 is provided with a roll surface of the workpiece W by giving a command corresponding to the operation amount output based on each axis value to the manipulator 10 and the servo motors 13a to 13f of the positioner 20 continuously. A one-stroke bead, that is, a spiral trajectory is drawn on Wr together with the movement of the manipulator and the positioner 20. As a result, the overlaying process is performed with the beads that uniformly cover the roll surface Wr of the workpiece W. FIG. 8 shows a state in which a spiral trajectory is drawn with beads on the roll surface Wr of the workpiece W. For convenience of explanation, FIG. 8 does not show a state where the spiral trajectory is uniformly covered with the bead B in order to clearly show the spiral trajectory.

Now, according to the first embodiment, there are the following features.
(1) The TP 36 according to the first embodiment teaches a spiral operation section with respect to the roll surface Wr of the work W of the torch 11 (working means) by moving the positioner 20 (work rotating means) and the manipulator 10 as teaching means, Teach spiral command parameters. The auxiliary storage device 35 of the robot control device 30 stores the spiral motion section and the parameters as storage means. Further, the CPU 31 of the robot control device 30 generates a spiral trajectory of the torch 11 (working means) in the spiral motion section by performing an interpolation calculation based on the parameters as a calculation means. As a result, when the overlay welding process is performed on the roll surface Wr of the work W, the process can be performed in a single spiral shape like a single stroke, and as a result, the roll surface Wr of the work W is uniform. In addition, it is possible to easily teach a program for executing the operation. Further, according to the present embodiment, since teaching is simple, the work preparation time can be greatly shortened.

(2) In the first embodiment, the parameters of the spiral command include the moving speed V (welding speed) of the torch 11 (working means) and the spiral pitch Pi.
As a result, it is possible to easily generate the spiral trajectory of the torch 11 in the spiral operation section.

  (3) In the first embodiment, the workpiece W has a roll surface Wr having a constant diameter (Rs) in the spiral motion section. Then, the CPU 31 of the robot control device 30 performs an interpolation calculation based on the diameter (Rs) and the parameters so as to generate a spiral trajectory with respect to the roll surface Wr, and the torch 11 (working means) in the spiral motion section. A spiral trajectory was generated. As a result, in the present embodiment, when overlay welding is performed on the workpiece W having the roll surface Wr having a constant diameter (Rs) in the spiral operation section, the processing is performed in a single spiral shape like one stroke. As a result, uniform processing can be performed on the roll surface Wr of the workpiece W, and a program for executing the work can be easily taught.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. 9 to 11 and FIGS. Note that the second embodiment will be described focusing on the configuration and operation different from the first embodiment.

  In the second embodiment, the hardware configurations of the robot control device 30, the TP 36, and the welding power source device 40 other than the positioner 20A are the same as those in the first embodiment, and the configuration of the positioner is different. That is, as shown in FIG. 10, the turning axis (that is, the rotation center axis) of the positioner 20A of the second embodiment is arranged perpendicular to the horizontal installation surface of the positioner 20A and the cylindrical workpiece W. A central axis is arranged to coincide with the pivot axis. Further, the second embodiment is different from the first embodiment in that a bead of a spiral trajectory is drawn as a spiral trajectory on an end surface having a flat surface of the workpiece W.

In the flowchart of FIG. 3 described in the first embodiment, the manual operation and the teaching program editing in S10 are performed as follows.
First, in S10, the operator manually operates the manipulator 10 and the positioner 20A for the spiral build-up operation using the keyboard 36b of the TP 36, and provides the teaching data and welding conditions of the start point Ps and end point Pe. Input (see FIG. 10). Here, the welding conditions include a welding speed (that is, a moving speed of TCP), a spiral pitch Pi, a spiral rotation direction, a welding current, a welding voltage, and the like.

  In S12, the CPU 31 edits the teaching data and welding conditions input in S10 into a teaching program for spiral overlaying and stores it in the auxiliary storage device 35, and ends this program editing process.

  Here, in the stored teaching program, the command for overlaying is represented by the name Spiral. The teaching program according to the present embodiment is for performing overlay welding in a spiral shape on the end surface Wt in which the spiral operation section from the start point Ps to the end point Pe has a plane of the cylindrical workpiece W. . The end face Wt is a plane orthogonal to the turning axis (rotation center axis) of the positioner 20A.

The spiral instruction (that is, the spiral instruction) is described as follows, for example.
Spiral Vel Pb pi Dir
Note that Vel is the moving speed (welding speed) of TCP, and Pb is the position and orientation of the torch 11 at the target point (end point) (that is, the end point Pe). Pi represents the helical pitch (mm) (see FIG. 5). Dir indicates the direction of rotation of the spiral, + is the right-handed screw direction, and-is the left-handed screw direction.

  The Spiral command has a TCP trajectory in a specified rotation direction at a specified pitch from the start point Ps (position taught immediately before the Spiral command) to the target position (end point Pe) with the rotation axis of the positioner 20A as the spiral center axis. It is a command to spiral. The spiral pitch Pi is designated based on the bead width determined by the welding conditions. Here, the helical pitch Pi is set in such an amount that enables the overlaying process to uniformly cover the end face Wt of the workpiece W with the beads, but is not limited to this value. Further, while the torch 11 is moved from the start point Ps to the end point Pe by the Spiral command, it means that the roll rotates by the number of times obtained by converting (Pb-Pa distance / spiral pitch Pi) into an integer.

Also in the second embodiment, the TCP moving speed V (welding speed) and the helical pitch Pi correspond to the parameters of the helical command.
In the following teaching example, a spiral (vortex) is drawn from the outer peripheral side to the inner side, but a spiral may be drawn from the inner side to the outer peripheral side by setting the start point Ps to the inner peripheral side and the end point Pe to the outer peripheral side.

Here, the spiral motion section in the second embodiment is a range surrounded by a circle having a radius Rs of the start point Ps and a radius Re of the end point Pe.
In the second embodiment, the process of S26 is omitted and the process of S24 is different in the flowchart of FIG. The process of S24 of 2nd Embodiment is demonstrated.

That is, in reproducing the spiral (vortex) on the end face Wt, the CPU 31 calculates the locus of the spiral as follows.
In the second embodiment, the Z value of the workpiece coordinates does not change, and instead, the circumferential radius changes from the radius Rs of the start point Ps to the radius Re of the end point Pe as shown in FIG. For this reason, the position of the interpolation point Pn is determined from the spiral equation: Xn = Rn · cos (θn) (11)
Yn = Rn · sin (θn) (12)
Zn = Zs (13)
Ask for. Zs is the value of the Z coordinate of the start point Ps and the end point Pe.

Here, θn in the above formulas (11) to (13) is obtained as follows.
θn is
θ1 = ΔS / Rs (14)
Note that ΔS = V · Δt.

θ2 = θ1 + ΔS / R1 (15)
θ3 = θ2 + ΔS / R2 (16)
…………
θn = θn-1 + ΔS / Rn-1 (17)
It becomes.

Since Rn is reduced by the pitch (Pi) in one round,
Rn = Rs−Pi · θn / (2π) (18)
It becomes.

When a spiral is drawn from the inner side to the outer peripheral side by setting the start point Ps to the inner peripheral side and the end point Pe to the outer peripheral side,
θ1 = ΔS / Re,
Rn = Rs + Pi · θn / (2π) may be set.

In addition, the torch position (posture) of the interpolation point is obtained by equally interpolating the start point posture / end point posture according to the progress rate of θ.
Now, according to 2nd Embodiment, while there exists an effect similar to (1) and (2) of 1st Embodiment, there exist the following characteristics.

  In the second embodiment, the work W has an end face Wt that is orthogonal to the turning axis (rotation center axis) of the positioner 20A (work rotating means) and has a plane in the spiral operation section. Then, the CPU 31 of the robot control device 30 calculates the radius of the start point Ps or the end point Pe in the spiral operation section so as to generate a spiral trajectory (spiral trajectory) with respect to the end surface Wt of the workpiece W as a calculation unit. An interpolation calculation is performed based on the radius, the moving speed V, and the spiral pitch Pi (parameter) to generate a spiral trajectory of the torch 11 in the spiral motion section (see FIG. 9).

  As a result, in the second embodiment, when overlay welding is performed on a workpiece W having an end face Wt that is orthogonal to the rotation center axis of the positioner 20A and has a flat surface in the spiral operation section, it is 1 like one stroke. Processing can be performed in the form of a spiral of books. And in 2nd Embodiment, while being able to perform a uniform process to the side surface (namely, end surface) of the workpiece | work W, the program which performs the operation | work can be taught easily.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. 12 and 13, and FIGS. 3 and 4. The third embodiment is a modification of the first embodiment, in which the bead B draws a spiral trajectory with respect to the roll surface Wr of the workpiece W having a conical surface as the roll surface Wr changes as the roll diameter changes. is there.

In the third embodiment, the flowchart for program editing shown in FIG. 3 is executed as in the first embodiment.
In the third embodiment, when the flowchart shown in FIG. 4 is executed, the process of S24 is different from that of the first embodiment, and other steps are performed in the same manner as in the first embodiment.

Here, the calculation process of the spiral locus in S24 of the third embodiment will be described.
As shown in FIG. 12A, the information on the spiral center axis (the direction cosine of the spiral center axis, the spiral center position) is the turning axis (that is, the rotation center axis) of the positioner 20. Here, if the swivel axis (rotation center axis) of the positioner 20 is the Z axis of the work coordinates, the direction cosine is (0, 0, 1) and the spiral center position is (0, 0, 0) in the work coordinates. (See FIG. 5).

Therefore, the interpolation point position (posture) on the spiral locus is calculated as follows.
As shown in FIG. 6B, the distance (ΔS) between the interpolation points Pn−1 and Pn is
ΔS = V · Δt.
Δt: interpolation pitch (sec) V: movement speed (welding speed)
It becomes.

Here, assuming that the rotation angle around the spiral central axis per interpolation is Δθ, the axial translation distance ΔHn between the interpolation points is
ΔHn = Pi · cosφ · Δθ / (2π)
= Κ ・ △ θ (19)
However, κ = Pi · cosφ / (2π) (20)
φ = arctan (| α |) (21)
α = (Re−Rs) / L (22)
(See FIGS. 12 (a) and 12 (b)).

Further, the moving distance ΔLn in the arc direction is ΔLn = Rn · Δθ (23)
It becomes.

Here, since ΔLn and Δθ are very small, the curvature of the curved surface (roll surface Wr) may be ignored.
ΔS ² = ΔHn ² + ΔLn ² (24)
Holds.

The position of the interpolation point Pn is calculated from the spiral equation: Xn = Rn · cos (θn) (25)
Yn = Rn · sin (θn) (26)
Zn = θn · κ (27)
Ask for.

However,
Rn = Rs + Zn · α (28)
It is.

Here, θn in the above formulas (25) to (27) is obtained as follows.
Substituting Equation (19), Equation (23), Equation (27), and Equation (28) into Equation (24) to obtain Δθ, Δθ = ΔS / sqrt (κ2 + (Rs + α · κ · θn) 2 ) (29)
It becomes.

Therefore, if the rotation angle at the start point Ps is 0, the rotation angle θn at each interpolation point is
θ0 = 0
θ1 = θ0 + ΔS / √ (κ ² + Rs ² )
θ2 = θ1 + ΔS / √ (κ ² + (Rs + α · κ · θ1) ² )
θ3 = θ2 + ΔS / √ (κ ² + (Rs + α · κ · θ2) ² )
………………………
θn = θn−1 + ΔS / √ (κ ² + (Rs + α · κ · θn−1) ² )
It becomes.

The torch posture at the interpolation point Pn is calculated by equal interpolation between the start point posture and the end point posture at the same ratio as the position.
In this way, each interpolation point at the work coordinates of the torch 11 is determined in S24. That is, the CPU 31 calculates a spiral trajectory.

  FIG. 13A shows a case where the spiral trajectory calculated as described above is seen through from the YZ plane of the work coordinates. FIG. 13B shows a case where the spiral trajectory calculated as described above is seen through from the XY plane of the work coordinates.

In the third embodiment, the spiral operation section is a range between the start point Ps and the end point Pe on the roll surface Wr that is a conical surface.
Now, according to 3rd Embodiment, while there exists an effect similar to (1) and (2) of 1st Embodiment, there exist the following characteristics.

  In the third embodiment, the workpiece W is configured such that the roll surface Wr has a conical surface in the spiral operation section. Then, the CPU 31 of the robot control device 30 uses the diameters and parameters (moving speeds) at the start point Ps and the end point Pe in the spiral operation section so as to generate a spiral trajectory with respect to the roll surface Wr as the calculation means. The spiral trajectory of the torch 11 (working means) in the spiral motion section is generated by performing interpolation calculation based on V and the spiral pitch Pi).

  As a result, in the spiral operation section, when processing such as build-up welding is performed on the workpiece W having the roll surface Wr formed in a conical surface, the processing is performed in a single spiral like a single stroke. As a result, uniform processing can be performed on the roll surface Wr of the workpiece W, and a program for executing the work can be easily taught.

In addition, you may change embodiment of this invention as follows.
In each of the above embodiments, the industrial robot control device is embodied as the robot control device 30 that performs overlay welding. However, the robot control device that performs coating, the control device of the robot that performs sealing, and the control of the robot that performs thermal spraying. It may be embodied in a device. In this case, in the case of a control device for a robot that performs coating, the coating gun corresponds to the working means. In the control device for the robot that performs sealing, the seal gun corresponds to the working means. In the control device of the robot that performs thermal spraying, the thermal spray gun corresponds to the working means.

  Even if embodied in such a control device, uniform processing can be performed on the side surface and roll surface of the workpiece.

1 is a schematic diagram of an industrial robot control system according to a first embodiment embodying the present invention. The block diagram of the robot control apparatus 30 similarly. The flowchart for program editing. Similarly, a flowchart of teaching program reproduction. Explanatory drawing which similarly shows the relationship between the workpiece | work W and a workpiece | work coordinate. (A) is explanatory drawing of distance L of start point Ps and end point Pe, (b) is explanatory drawing of (DELTA) S, (DELTA) Ln, and (DELTA) Hn. Explanatory drawing of the process in a target point (end point Pe). Explanatory drawing of the spiral locus of 1st Embodiment. Explanatory drawing of the spiral locus of 2nd Embodiment. Explanatory drawing of start point Ps and end point Pe. Explanatory drawing of the radius of the start point Ps and the end point Pe similarly. (A) is explanatory drawing of distance L of the starting point Ps of 3rd Embodiment, and the end point Pe, (b) is explanatory drawing which shows the relationship with the amount of movements of the spiral center axis direction per pitch. (A) is explanatory drawing of the spiral locus | trajectory seen from the YZ plane of the workpiece coordinate of 3rd Embodiment, (b) is explanatory drawing of the helical locus | trajectory similarly seen from the XY plane of the workpiece coordinate.

Explanation of symbols

10 ... Manipulator, 11 ... Torch (working means),
20 ... Positioner (work rotating means), 31 ... CPU (calculating means),
35 ... auxiliary storage device (storage means), 36 ... TP (teaching means).

V: Movement speed, W: Workpiece, Wr: Roll surface, Wt: End surface,
e: End point, Pi: Spiral pitch, Ps: Start point.

Claims (5)

In an industrial robot control apparatus for controlling a workpiece rotating means for rotating a workpiece and a manipulator having a working means for performing work on the workpiece to perform cooperative work,
Teaching means for moving the workpiece rotating means and the manipulator to teach a spiral movement section of the working means, and teaching parameters of a spiral command;
Storage means for storing the spiral motion section and the parameter;
An industrial robot control apparatus comprising: an arithmetic unit that performs an interpolation calculation based on the parameter to generate a spiral trajectory of the working unit in a spiral operation section.   2. The industrial robot controller according to claim 1, wherein the parameters of the spiral command include a moving speed and a spiral pitch of the working means. The workpiece has a roll surface having a constant diameter in a spiral operation section,
The calculation means generates a spiral trajectory of the working means in a spiral motion section by performing an interpolation calculation based on the diameter and the parameter so as to generate a spiral trajectory with respect to the roll surface. The industrial robot control device according to claim 2. The workpiece has a conical surface with a roll surface in a spiral motion section,
The working means in the spiral motion section by performing an interpolation calculation based on the diameters at the start and end points in the spiral motion section and the parameters so that the computing means generates a spiral trajectory with respect to the roll surface. The industrial robot controller according to claim 2, wherein a spiral trajectory is generated. The workpiece has an end surface that is orthogonal to the rotation center axis of the workpiece rotating means and has a plane in the spiral operation section,
The operation in the spiral motion section is performed by performing an interpolation operation based on the diameter of either the start point or the end point in the spiral motion section and the parameter so that the calculation means generates a spiral trajectory with respect to the end face. The industrial robot control device according to claim 2, wherein a spiral trajectory of the means is generated.

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