JP3304484B2 - Industrial robot controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tool moving device capable of changing the position and posture of a tool such as a welding torch and a sealing gun, and to changing the posture and position of a work to be worked. An industrial robot control device having a work moving device capable of moving a tool and a work simultaneously and cooperatively with respect to a work position of the work. The present invention relates to a control device for an industrial robot having a so-called weaving operation for swinging operation. According to a second aspect of the present invention, in the industrial robot, the so-called arc sensor is used, in which the tool is used as a welding torch, and an arc generated at the time of welding is detected to cause the welding torch to follow the work position of the workpiece. The present invention relates to a control device for an industrial robot.

[0002]

2. Description of the Related Art In recent years, an industrial robot has been constructed by combining a work moving device such as a positioner that mounts a work to change the posture of the work or a slider that mounts the positioner and a tool moving device that works on the work. Controls such as (1) performing welding work while rotating the work to change the posture to an appropriate posture, and (2) performing welding work while moving the slider for a work larger than the operating range of the industrial robot. Is being done. For example,
Japanese Patent Application Laid-Open No. 3-228592 discloses a control method in which a welding torch is simultaneously moved while a work is being operated to perform a cooperative operation. It is also known to use a robot instead of a positioner and to work with an industrial robot combining two robots.

On the other hand, in an arc welding operation, there have been many proposals relating to so-called arc sensor copying as a method for detecting a welding line for aligning a welding torch with a welding line of a workpiece, that is, a groove center position of a workpiece. It has been done. For example, in JP-A-51-91851, arc welding is performed while the welding torch swings in the welding width direction, that is, weaving is performed, and the welding torch follows the line to be welded by controlling the center position of the weaving. Has been revealed. Further, in order to reduce the influence of fluctuation due to noise or the like, Japanese Patent Application Laid-Open No. 52-9657 discloses an item relating to arc sensor scanning in which detected welding currents are integrated and compared.

[0004]

In the case where the line to be processed of the work has a fixed relation to the reference plane of the robot,
The weaving operation of the tool and the copying control of the arc sensor in the welding operation can be performed without any problem by the above-mentioned conventional technology. By the way, in the case of an industrial robot that combines a work moving device and a tool moving device, when the robot is operated in a cooperative manner while weaving a tool with respect to a work line of the work, the work line of the work is not changed during the machining operation. It always changes with respect to the reference plane of the robot, and the weaving direction of the tool is shifted with respect to the desired width direction. In addition, the copying control of the arc sensor is performed,
In a welding robot that performs cooperative operation while weaving a welding torch, the welding line changes constantly with respect to the robot installation reference plane during the welding operation. In addition to the problem of misalignment, the position to be corrected of the tip of the welding torch by the arc sensor does not coincide with the line to be welded, so that the tip of the torch is in a desired state, that is, on the line to be welded. There was a problem that it was not corrected.

[0005]

According to a first aspect of the present invention, there is provided a work moving device capable of changing the position and orientation of a work, and a tool for performing an operation on the work is attached to the work and the position and orientation of the tool while weaving. The present invention is applied to a control device for an industrial robot that has a tool moving device capable of changing a tool and works by cooperatively moving a tool and a work at the same time. The feature is that two continuous teaching data are extracted from the work program that stores the work contents, and the trajectory between the teaching points is based on the position and orientation of the tool with respect to the work and a predetermined reference coordinate system. and first calculating means for calculating the interpolation point representing the position and orientation of the workpiece was now of the position and orientation of the tool relative to the said workpiece
Second calculating means for calculating a <br/> progress vector from the times of the interpolation position vector and the previous interpolation position vector, the work
Third calculating means for calculating the position and orientation of the traveling coordinate system with reference to the tool using the position and orientation of the tool with reference to the tool and the travel vector, A fourth calculating means for calculating a correction position of the tool in the coordinate system; and a tool based on the workpiece.
Of the traveling coordinate system based on the tool
Fifth calculating means for calculating the position and orientation of the tool with reference to the work from the position and orientation and the corrected position of the tool, and operating amounts of the tool moving device and the work moving device based on the fifth calculation result. A sixth calculating means for calculating and a driving means for simultaneously driving the tool moving device and the work moving device based on the sixth calculating result are provided.

According to the second aspect of the present invention, a work moving device capable of changing the position and orientation of a work, and a tool for performing work on the work are attached to the work moving device, and the operation correction value is received from the arc sensor unit while weaving. And a tool moving device that can change the position and orientation of the tool, and is applied to a control device of an industrial robot that performs a work by moving a tool and a work simultaneously and cooperatively. The feature is that two continuous teaching data are extracted from the work program that stores the work contents, and the trajectory between the teaching points is based on the position and orientation of the tool with respect to the work and a predetermined reference coordinate system. this interpolation position vector to first calculating means for calculating the interpolation point representing the position and orientation of the workpiece was, the position and orientation of the tool relative to the said workpiece
A second calculating means for calculating a progression vector from the previous interpolation position vector and a tool based on the workpiece.
Using the position and orientation and the travel vector , the tool is referenced
A third calculating means for calculating the position and orientation of the traveling coordinate system , and a tool displacement correction amount by the arc sensor and the tool displacement relating to the weaving amplitude, and a fourth correction means for calculating the tool correction position in the traveling coordinate system. and computing means, said
The position and orientation of the tool with respect to the workpiece and the
Position and orientation of the traveling coordinate system and the corrected position of the tool
A fifth calculating means for calculating the position and orientation of the tool based on the workpiece from the above, and a sixth calculating means for calculating the operation amounts of the tool moving device and the work moving device based on the fifth calculation result.
And driving means for simultaneously driving the tool moving device and the work moving device based on the sixth calculation result.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. For example, an industrial robot using a welding torch as a tool will be described in the following order. (1) Configuration of industrial robot system (2) Configuration of control device (3) Principle of control method (3-1) Definition of coordinate system and symbol of each component (3-2) Position and orientation of each component (3-3) Teaching work (3-4) Weaving processing method and arc sensor correction method (4) Playback operation processing (5) Modification

(1) Configuration of Industrial Robot System FIG. 3 is a schematic diagram showing the entire system of an industrial robot, for example, a welding robot according to the present invention. As shown in FIG. 3, the industrial robot system according to the present embodiment includes a work moving device 1 including a manipulator having six degrees of freedom having a gripper 11 for gripping a work 1 which is a work target.
0, an industrial robot comprising a tool moving device 20 for moving the tool 2 which is an arc welding torch, a robot control device 3 for controlling the moving devices 10 and 20, and a teaching operation. A teaching pendant 4, an operation box 5 for switching between teaching operation and automatic operation operation, and generating a start signal for automatic operation, a welding power source 6 for supplying welding current, and measuring the welding current. An arc sensor unit 7 for outputting a sensor correction signal for optimizing the position of the welding torch, that is, the tool 2, and based on the work program taught and the sensor correction signal from the arc sensor unit, This is an automatic device that performs an arc welding operation following the line to be welded while performing a coordinated operation between the tool and the tool 2.

(2) Configuration of Control Device As shown in FIG. 4, the robot control device 3 basically includes a CPU 30 which is a single microprocessor,
A ROM 31 as a memory for storing arithmetic means described below as a control program, a RAM 32 as a memory for storing a calculation result generated in an arithmetic process and for storing a work program, a teaching pendant and an operation box, Outputs command values to an I / F 33 for exchanging information among a welding power source, an arc sensor unit, and a control device, and to a servo motor for driving each of the work moving device 10 and the tool moving device 20. And a servo control circuit 36, 37 for controlling the servomotor in accordance with the command value.

(3) Principle of Control Method (3-1) Definition of Coordinate System and Symbols of Each Component In FIG. 5, the coordinate system in the industrial robot system according to the present invention is shown using the symbol Σ. The symbols used for each element are shown below. The coordinate system that is the basis of the industrial robot system is called the world coordinate system, and Σwo
Using the symbol rld, the coordinate origin of the world coordinate system is Oworl
d, each coordinate axis is indicated by the symbol (Xworld, Yworld, Zworld).

A work-side base coordinate system is provided on the installation reference plane of the work moving device 10, the symbol of w-base is used, the coordinate origin of the work-side base coordinate system is Ow-base, and each coordinate axis is (X
(w-base, Yw-base, Zw-base). A work side mechanical interface coordinate system is provided on the output flange surface of the work moving device 10, and the symbol of Σw6 is used. The coordinate origin of the work side mechanical interface coordinate system is Ow.
6. Each coordinate axis is indicated by the symbol (Xw6, Yw6, Zw6). A work coordinate system serving as a reference of the work held by the gripper 11 attached to the output flange surface of the work moving device 10 uses a symbol of Σwork, and the coordinate origin of the work coordinate system is O.
work, each coordinate axis is indicated by the symbol (Xwork, Ywork, Zwork). A tool-side base coordinate system is provided on the installation reference plane of the tool moving device 20, a symbol of Σt-base is used, the coordinate origin of the tool-side base coordinate system is Ot-base, and each coordinate axis is (Xt-bas
e, Yt-base, Zt-base).

A tool-side mechanical interface coordinate system is provided on the output flange surface of the tool moving device 20, and Δt6
The coordinate origin of the tool-side mechanical interface coordinate system is Ot6, and each coordinate axis is (Xt6, Yt6, Zt
Shown by 6). The tool coordinate system provided at the tip of the tool 2 attached to the output flange surface of the tool moving device 20 uses the symbol Σtool, and the coordinate origin of the tool coordinate system is Otoo
l, each coordinate axis is indicated by the symbol (Xtool, Ytool, Ztool).

(3-2) Relationship between Position and Orientation of Each Component FIG. 6 shows the relationship between each component and the coordinate origin and the position and orientation. The relationship between adjacent links in the work moving device 10 can be represented by the following homogeneous transformation matrix Awj of the following Equation 1 using link parameters according to the well-known Denabit-Hamberg notation.

[0014]

(Equation 1)

Therefore, the position and orientation of the work-side mechanical interface coordinate system Σw6 based on the work-side base coordinate system Σw-base in the work moving device 10 is expressed by a homogeneous transformation matrix TW as follows.

[0016]

(Equation 2)

The link parameters are shown in Table 1.

[0018]

[Table 1]

The relationship between adjacent links in the tool moving device 20 is expressed by a homogeneous transformation matrix Atj as in the following equation 3, as in the case of the work moving device.

[0020]

(Equation 3)

As in the case of the work moving device 10, the tool-side base coordinate system Σt-ba in the tool moving device 20 is used.
The position and orientation of the tool-side mechanical interface coordinate system Σt6 based on se is represented by a homogeneous transformation matrix Tt as shown in the following Expression 4.

[0022]

(Equation 4)

The link parameters are shown in Table 2.

[0024]

[Table 2]

World coordinate system: Work side base coordinate system based on Σworld: Installation relation of Σw-base is given by the following equation (5).
Is defined by a homogeneous transformation matrix Zw.

[0026]

(Equation 5)

The world coordinate system: the tool-side base coordinate system based on Σworld: the installation relationship of 設置 t-base is defined by a homogeneous transformation matrix Zt as Equation 6 below.

[0028]

(Equation 6)

The position of the tool, that is, the position and orientation of the tip of the torch with reference to the mounting surface of the welding torch, can be expressed by a homogeneous transformation matrix Et of the following equation (7).

[0030]

(Equation 7)

The homogeneous transformation matrix representing the gripper holding the work is set as the following equation (8).

[0032]

(Equation 8)

It should be noted that Zt, Et, Zw, Ew of the above elements
Is a unique value when the structure of each of the mobile devices 10 and 20 is specified. What changes are the position / posture Tt of the tool moving device and the position / posture Tw of the work moving device, which can be obtained by performing forward conversion of the joint variables of the respective moving devices 10 and 20.

Using the above-mentioned homogeneous transformation matrix, the position and orientation of the tool coordinate system with respect to the world coordinate system are expressed by the following equation, that is, Equation 9:

[0035]

(Equation 9)

On the work side, the following equation holds, that is, equation (10).

[0037]

(Equation 10)

Assuming that the position and orientation of the tool coordinate system with respect to the work coordinate system is (work Xtool), the following equation is obtained:
Holds.

[0039]

[Equation 11]

Work moving device 10 and tool moving device 20
In the reproduction of the cooperative operation in which the two are simultaneously operated, the welding torch with respect to the work, that is, the relative position and orientation (work Xtool) of the tool 2 is designated by interpolation so as to be a predetermined one. Further, when the movement of the work with respect to the world coordinate system (world Xwork) is specified by interpolation, as a result, the position and orientation of the tool with respect to the world coordinate system (world Xtool) are automatically determined from Equation 11. In order to perform such a playback operation, the movement of the work relative to the world coordinate system (world Xwo
rk) and the relative position and orientation (workXtool) are calculated and stored in the work program.

(3-3) Teaching Work In order for the work and the welding torch to perform an arc welding work following a welding line while performing a coordinated operation, the operator switches teaching / reproduction of the operation box 5 shown in FIG. Switch S
W1 is set on the teaching side, and a work program is first created using the teaching pendant 4 shown in FIG. The procedure by the operator is as follows. The moving device is selected by SW3 in the teaching pendant 4 and the work moving device 10 or the tool moving device 20 is selected by pressing the operation instruction button SW4.
To set the relative position and orientation of the desired workpiece and tool. After confirming this state, in order to store the relative state in the control device, the storage button SW5 of the teaching pendant is pressed, and the relative speed is input by the number input button SW7.

At the start position and the end position of the weaving operation, the weaving button SW8 of the teaching pendant 4 is pressed, the whole wefting amplitude Wth and the frequency Frq are input by the number input button SW7, and then the storage button SW5 is pressed. Press to store it in the work program. Further, at the start position and the end position of the copying control by the arc sensor, the sensing button SW9 is pressed and the storage button SW5 is pressed to store the data in the work program. In response to such an operation by the operator, the control device performs the following processing to create a work program shown in FIG.

The storage button SW of the teaching pendant 4 for storing the state of the relative position and orientation of the work and the tool
When 5 is pressed, the control device calculates the position and orientation of Σwork based on Σworld by Equation 10, and transforms the position and orientation of Σtool based on Σwork by Equation 11,
That is, it is calculated by Expression 12.

[0044]

(Equation 12)

Based on both the position and orientation data and the welding speed, which is the relative speed of the tool to the workpiece set by the numeric key of the teaching pendant, storage data as an example is created in part (a) of FIG. In addition, at the start position and the end position of the weaving operation, stored data, an example of which is shown in FIG. 9B, and at the start position and the end position of the scanning control by the arc sensor, FIG. The storage unit creates storage data showing an example. Then, the operator sets the teaching / reproduction changeover switch SW1 of the operation box 5 to the reproduction side and activates the start button SW
By pressing 2, the control device reproduces sequentially based on the work program taught.

(3-4) Weaving Treatment Method and
The j-th and j-1st teaching data stored in the arc sensor correction method operation program are extracted, and a trajectory between teaching points is created. Details will be described in (4) the processing of the reproduction operation of the item, but here, i-1 when the robot system is operating from the state of the robot system stored at the j-1th position toward the jth position.
The principle of a method of correcting the position of the tool based on the workpiece by the weaving and the arc sensor when operating from the i-th interpolation to the i-th interpolation will be described. i
The position and orientation of the tool with respect to the work in the -1st interpolation (work X tool) The position and orientation of the tool with respect to the work in the _i-1 and i-th interpolations (work X
tool) _i is set as the following expression, that is, Expression 13 and Expression 14.

[0047]

(Equation 13)

[0048]

[Equation 14]

The traveling vector ν _i shown in FIG. 10 is calculated by using the welding torch with respect to the workpiece, that is, the moving direction of the tool 2, and is calculated by Expression 15.

[0050]

(Equation 15)

The coordinate origin of the traveling coordinate system: Σseam is the same as the origin of the tool coordinate system: Σtool, the Z coordinate axis of the traveling coordinate system is set parallel to the traveling vector, and the X coordinate axis of the traveling coordinate system is the tool coordinate. It is defined as being set orthogonal to the Z coordinate axis of the traveling coordinate system on a plane formed by the Z axis of the system and the Z coordinate axis of the traveling coordinate system, and the Y coordinate axis of the traveling coordinate system is set orthogonal to the plane. . Therefore, first, from Equation 14,
Tool posture with reference to the work coordinate system: w Rt is Equation 1
It can be expressed as 6.

[0052]

(Equation 16)

[0053] with a progress vector based on the work coordinate system determined by Equation 15, Z components of the traveling vector based on the tool coordinate system: t as _i, Y component: t os _i, and X components: t the ns _i is calculated by the following equation.

[0054]

[Equation 17]

Therefore, the position and orientation of the traveling coordinate system with reference to the tool coordinate system are obtained by the following equations.

[0056]

(Equation 18)

The weaving displacement ΔW _i and the sensor cumulative correction TS are set in the Y-axis direction of the traveling coordinate system. Therefore, based on the traveling coordinate system, the corrected tool position and orientation obtained by adding the weaving displacement and the sensor cumulative correction TS.
seam Xtool 'is given by the following equation.

[0058]

[Equation 19]

From the above, the corrected tool position and orientation workXtool ' _{i based} on the i-th work is given by the following equation:
That is, it can be calculated by Expression 20.

[0060]

(Equation 20)

(4) Processing of Reproduction Operation FIGS. 11 to 22 are flowcharts of the reproduction operation executed by the control device 3.

The operator sets the teaching / playback changeover switch SW1 of the operation box 5 to the playback side and activates the start button SW
By pressing 2, the process of this routine is started. First, in step S1, parameter j is set to 1, and in step S2, sensor control execution which is a parameter for determining whether or not to execute the copying control by the arc sensor. The data SC is reset to zero, and the accumulated correction amount TS, which is the accumulation of the correction amount ΔS from the arc sensor unit,
After resetting to zero, in step S3, the first
Whether or not to head to the teaching point is determined by the parameter j. If it is 1, the process proceeds to step S5, and if it is 2 or more, the process proceeds to step S4.

In step S4, the data is stored in the RAM 32,
From the j-th and (j-1) -th teaching data in the work program shown in FIG. 9, the operation target TD (j)
And the operation target TD (j-1),
Proceed to 8. On the other hand, in step S5, the position and orientation wor of the tool with respect to the workpiece at the start of the reproduction operation
After calculating k Xtool and the position and orientation world Xwork of the work based on the world coordinate system, in step S6
A previous interpolated position vector Pp is created from the data of workXtool of 1 row, 4 columns, 2 rows, 4 columns, and 3 rows and 4 columns, stored in the RAM 32, and then the first teaching data T from the work program.
D (1) is fetched, and the process proceeds to step S8. Step S
In step 8, if the j-th teaching data of the work program includes the start or end of weaving, the process proceeds to step S9, and if not, the process proceeds to step S12.

In step S9, it is determined whether the weaving is started or ended. If the weaving is started, the weaving amplitude Wth and the weaving frequency F are determined from the j-th teaching data.
rq is fetched, and the process proceeds to step S12. Step S
If weaving is completed in step 9, the process proceeds to step S11, where Wth and Frq are cleared to zero.
Proceed to. In step S12, it is determined whether or not the j-th teaching data of the work program includes start or end of the arc sensor.
Proceed to 13. In step S13, it is determined whether or not the start of the arc sensor.
After setting 1 to the parameter SC indicating the execution of the sensor control, the start of the sensor control is notified to the arc sensor unit 7 through the interface I / F33.

If the sensor control has been completed in step S13, the sensor control execution data SC and the cumulative correction amount TS are cleared to zero. And the interface I / F 33
After instructing the arc sensor unit 7 to end the detection through, the process proceeds to step S18. In a step S18, an operation increment is calculated, and in a step S19, an interpolation process is performed. Then, in step S20, the teaching data number of the target operation is incremented by one. In step S21, the presence or absence of the teaching data of the target operation is determined.
Return to 3 and execute again. If there is target teaching data in step S21, calculation is performed again from step S3. If there is no target teaching data, the process ends.

FIG. 15 shows a subroutine for calculating the operation increment in step S18 in FIG. In step S1801, a homogeneous transformation matrix (workXtool) _j representing the position and orientation of the tool with respect to the work in the jth teaching data and the j-1st teaching data (work
Xtool) _j−1 to calculate the increment of only the position of the tool with respect to the workpiece, and divide by the designated speed Vj to obtain the required time Tj. In step S1802, using the Tj, the increase amount ΔU of the position and orientation of the tool relative to the work per unit time is calculated from the j-th and j−1th teaching data relating to the position and orientation of the tool relative to the work, It is calculated by the following equation.

[0067]

(Equation 21)

Further, also in step S1803, the amount of increase ΔW in the position and orientation of the work with reference to the world coordinate system is calculated by the following equation using Tj, and the process ends. ΔU
And ΔW are used in the interpolation processing in step S19 in FIG.

[0069]

(Equation 22)

The interpolation processing in step S19 is shown by flowcharts in FIGS. First, step S190
The parameter i is cleared to zero by 1 and a step S190
After adding 1 to the parameter i in step 2, step S190
In 3, the elapsed time Tpi is calculated by the following equation. Note that Δ
T is the interpolation cycle time.

[0071]

(Equation 23)

Next, in step S1904, the position and orientation of the workpiece with respect to the world coordinate system (wo
rld Xwork) _i is calculated by the following equation.

[0073]

(Equation 24)

Similarly, in step S1905, the position and orientation of the tool (work Xto
ol) Calculate _i by the following formula.

[0075]

(Equation 25)

In step S1906, it is determined whether or not to perform sensor control based on whether or not the parameter SC is 1.
In the case of 1, the correction amount: ΔS is fetched from the sensor unit 7 through the interface 33 in step S1907. After adding to the cumulative correction value TS, the process proceeds to step S1908. If sensor control is not performed in step S1906, the process advances to step S1908.

In step S1908, whether to perform weaving is determined by the parameter Wth. When weaving is performed, the progress vector calculation process, the progress coordinate system calculation process, the tool position correction calculation (1), and the tool position correction calculation (2) in steps S1910 to S1913 are sequentially performed. If weaving is not to be executed, in step S1909, the position and orientation of the tool (work Xtool) _i with respect to the reference point of the work, _i.
The data of the fourth column of each of the rows and the third row is taken out, the previous interpolation position vector Pp is created and stored in the RAM 32. Pp
Corresponds to wPt _i-1 in Expression 13. Next, in step S1914, a homogeneous transformation matrix Twi indicating the position and orientation of the gripper attachment reference point with reference to the installation reference plane of the work moving device is calculated by the following equation.

[0078]

(Equation 26)

In step S1915, a homogeneous transformation matrix Tti indicating the position and orientation of the tool attachment reference point with reference to the installation reference plane of the tool moving device is calculated by the following equation.

[0080]

[Equation 27]

Based on the position and orientation of the two moving devices in the i-th interpolation obtained in this way, in step S1916, the inverse transformation process is performed to obtain the joint variables θw1 to θw6 of the work moving device and the joint variables θt1 to θt1 of the tool moving device. θt6 is calculated, and in step S1917, the command value of the motor attached to each joint is further calculated based on each joint variable. When the time reaches Tpi, the CPU 30 outputs the servo command value to the output port 34. In step S1918, it is determined whether or not the j-th target position / posture has been reached by comparing with the required time Tj. If the j-th target position / posture has not been reached, the process is repeated from step S1902. When the target j-th teaching data position is reached, this subroutine ends and returns to the main routine.

The progress vector calculating process shown in step S1910 of FIG. 17 is shown as a subroutine in FIG.
In step S 19101, a current interpolation position vector w Pt _i is calculated from three pieces of data in a homogeneous transformation matrix representing the position and orientation of the tool with respect to the workpiece, ie, 1 row, 4 columns, 2 rows, 4 columns and 3 rows, 4 columns. Calculated, and in step S19102,
The calculated current interpolation position vector w Pt _i and RA
From the previous interpolation position vector Pp stored in M, the progress vector νi is calculated by the following equation.

[0083]

[Equation 28]

In step S 19103, i
The current interpolation position vector calculated by interpolation is used for future i +
For use in 1 interpolation, the previous interpolation position vector is R
AM and the subroutine ends.

The progress coordinate system calculation processing shown in step S1911 of FIG. 17 is shown as a subroutine in FIG. In step S 19111, nine pieces of data of the same row transformation matrix representing the position and orientation of the tool with respect to the workpiece as 1 row, 1 column to 3 rows, 3 columns are extracted, and a 3 row, 3 column orientation matrix wRt is created. The Z component of the traveling coordinate system Σseam is calculated using the inverse matrix of the tool's posture matrix wRt based on the work, that is, the work's posture matrix w Rt ^-1 based on the tool and the progress vector ν _i based on the work. tas _i is calculated by the following equation.

[0086]

(Equation 29)

The Z-axis component of the tool coordinate system is [0, 0, 1]
Than that shown and, Y components of the progression coordinate system taking the inner product between t the as _i is determined by the equation:, t the as _i and t os _i X component of the traveling coordinate system than the inner product of can be calculated.

[0088]

[Equation 30]

The coordinate origin of the traveling coordinate system coincides with the coordinate origin of the tool coordinate system. Therefore, the traveling coordinate system based on the tool is obtained by the following equation.

[0090]

(Equation 31)

Thus, this subroutine is completed. FIG.
Tool position correction calculation (1) shown in step S1912
Is shown as a subroutine in FIG. Step S19
At 121, the displacement of the weaving to be moved in the Y-axis direction of the traveling coordinate system is calculated by the following equation.

[0092]

(Equation 32)

Further, in step S 19122, the correction position (seamXtool ′) _i of the tool based on the traveling coordinate system is determined by the accumulated correction value TS of the sensor correction for correcting the traveling coordinate system in the Y-axis direction and the weaving displacement. Calculate by the following equation and end.

[0094]

[Equation 33]

The tool position correction calculation (2) shown in step S1913 of FIG. 17 is shown as a subroutine in FIG. In step S 19131, the (seamXtool ′)
_{Using i} , the position and orientation of the tool with respect to the workpiece after weaving and correction by the arc sensor (workXtool
') _I is calculated by the following equation.

[0096]

(Equation 34)

Then, in step S 19132, the calculated (workXtool ′) is substituted into the position and orientation (workXtool) _i of the tool with respect to the work calculated based on the work program, and the process ends.

(5) Modification In the above embodiment, the tracing correction from the arc sensor also detects the nozzle direction of the welding torch, and the cumulative correction amount is TS.
z

This embodiment can be applied by simply changing the expression (19) into the following expression.

[0099]

(Equation 35)

Although the above description has been made on the assumption that the weaving operation and the copying control by the arc sensor are performed, the copying by the arc sensor is not performed.
Of course, it can be a weaving operation drink.

[0101]

As described above in detail, in the control device for an industrial robot according to the present invention, the direction in which the weaving swings and the correction direction by the arc sensor added as necessary are determined by the reference point of the workpiece. (Work coordinate system) is used as a reference, and is determined by a traveling coordinate system obtained by the traveling direction of the tool and the posture of the tool. Therefore, the weaving operation has the following features. (1) Even if the direction in which the tool operates or the posture changes, the swinging direction of weaving is always on a plane orthogonal to the traveling direction of the tool and orthogonal to the center line of the tool. For this reason, when the tool is, for example, a welding torch, the welding torch swings on a plane perpendicular to the direction in which welding proceeds and perpendicular to the center line of the welding torch, and a favorable welding result is obtained. (2) Even if the position and orientation of the work changes due to the movement of the work moving device, no change occurs when the swinging direction of the weaving is viewed with respect to the work. Therefore, for example, in the case of a welding operation shown in FIG. 1, even if welding is performed while changing the posture of the work, a preferable welding result is obtained since the swinging direction of the weaving when viewed with respect to the work does not change. can get. Further, when the copying control by the arc sensor is further performed on the weaving operation, the following items are added in addition to the effects (1) and (2). (3) Even if the direction in which the tool operates or the posture changes, the correction direction is perpendicular to the traveling direction of the working welding torch and is corrected on a plane perpendicular to the center line of the welding torch, so that the correction is effective. Can be. (4) Even if the posture of the work changes during the work as shown in FIG. 2, the correction direction and the correction amount when viewed with respect to the work do not change. Therefore, an appropriate correction result can be obtained. As described above, in the embodiment according to the present invention, the workpiece and the tool such as the welding torch are simultaneously moved to perform the weaving operation, or to perform the welding operation by the weaving operation and the scanning control by the arc sensor. In addition, it is possible to perform a proper operation without changing the swinging direction of the weaving and the correction direction by the sensor correction with respect to the workpiece.

[Brief description of the drawings]

FIG. 1 is a diagram showing a weaving state of a welding torch as a tool in an industrial robot to which the present invention is applied.

FIG. 2 is a diagram showing a state of the tool following an arc sensor of the industrial robot to which the present invention is applied;

FIG. 3 is a schematic diagram showing the entire embodiment of the present invention.

FIG. 4 is a block diagram of a control device in the industrial robot system of FIG.

FIG. 5 is a diagram showing a coordinate system and symbols of components in the industrial robot system of FIG. 3;

FIG. 6 is a diagram showing a relationship between each component in the industrial robot system of FIG. 3, a coordinate system origin, and a position and orientation.

7 is a front view showing an example of an operation box in the industrial robot system of FIG.

FIG. 8 is a front view showing one example of a teaching pendant in the industrial robot system of FIG. 3;

FIG. 9 is a diagram showing a configuration example of a work program stored in a RAM of FIG. 4;

FIG. 10 is a schematic diagram showing a traveling vector and a traveling coordinate system according to the present invention.

11 is a flowchart showing a part of a process of a reproducing operation executed by the control device of FIG. 3;

FIG. 12 is a flowchart showing a part of a process of a reproducing operation executed by the control device of FIG. 3;

FIG. 13 is a flowchart showing a part of processing of a reproducing operation executed by the control device of FIG. 3;

FIG. 14 is a flowchart showing a part of a process of a reproducing operation performed by the control device of FIG. 3;

FIG. 15 is a flowchart showing a process of calculating an operation increment, which is a subroutine of FIG.

FIG. 16 is a flowchart showing an interpolation process which is a subroutine of FIG.

FIG. 17 is a flowchart showing an interpolation process which is a subroutine of FIG.

FIG. 18 is a flowchart showing an interpolation process which is a subroutine of FIG.

FIG. 19 is a flowchart showing a progress vector calculation process which is a subroutine of FIG.

20 is a flowchart showing a process of calculating a progress vector coordinate system, which is a subroutine of FIG.

21 is a flowchart showing a tool position correction calculation (1) which is a subroutine of FIG.

FIG. 22 is a flowchart showing a tool position correction calculation (2) which is a subroutine of FIG.

[Explanation of symbols]

1. Workpiece, 2. Tool, 3. Control device,
4 teaching pendant, 5 operation box, 6 welding power supply, 7 arc sensor unit, 10 work moving device, 11 gripper, 20 tool moving device
30 ... CPU, 31 ... ROM, 32
... RAM, 33 ... I / F (interface),
34 ... output port, 36 ... servo control circuit (for work moving device), 37 ... servo control circuit (for tool moving device) 38 ... minute period, Oworld ... coordinate origin of world coordinate system (@world) OworK ... work coordinate system (原点 work) Coordinate origin Ow-base… Work-side base coordinate system (Σw-base) coordinate origin Ow6… Work-side mechanical interface coordinate system (Σw6) coordinate origin Otool… Tool coordinate system (Σtool) coordinate origin Ot-base … Coordinate origin of tool-side base coordinate system (Σt-base) Ot6… Coordinate origin of tool-side mechanical interface coordinate system (Σw6) νi… Progress vector Oseam… Coordinate origin of progress coordinate system (Σseam) θw1 to θw6 Joints, θt1 to θt6 ...
Lj0 to Lw1 ... Link of work moving device, Lt0 to Lt6 ... Link of tool moving device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI G05B 19/4093 G05B 19/4093 P (56) References JP-A-60-230207 (JP, A) JP-A-60-124475 ( JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) B23K 9/12 B23K 9/127 B25J 13/00 G05B 19/18 G05B 19/4093

Claims (2)

(57) [Claims] 1. A work moving device capable of changing the position and orientation of a work, and a tool moving device capable of changing the position and posture of the tool while attaching a tool for performing work to the work and weaving the work. In a control device for an industrial robot that performs a work by simultaneously moving a tool and a work in cooperation with each other, a continuous teaching data is extracted from a work program storing work contents, and a trajectory between teaching points is obtained. a first calculating means for calculating the interpolation point representing the position and orientation of the workpiece relative to the position and orientation and a predetermined reference coordinate system of the tool relative to the workpiece, before
This interpolation position of the position and orientation of the serial work with reference to the tool
Second calculating means for calculating a traveling vector from the location vector and the previous interpolation position vector, the workpiece as a reference
The position and orientation of the tool and using the traveling vector, Tsu
Calculating the position and orientation of the traveling coordinate system based on the rule
Calculating means for calculating the tool displacement related to the weaving amplitude, the tool calculating position in the traveling coordinate system, and the position of the tool with respect to the workpiece
The posture and the position and posture of the traveling coordinate system based on the tool
Fifth calculating means for calculating the position and orientation of the tool based on the work from the corrected position of the tool, and calculating the operation amounts of the tool moving device and the work moving device based on the fifth calculation result. A control device for an industrial robot, comprising: a calculating means of (6); and a driving means for simultaneously driving a tool moving device and a work moving device based on the sixth calculation result. 2. A work moving device capable of changing the position and orientation of a work, and a tool for performing a work on the work are attached to the work moving device. An industrial robot control device having a tool moving device capable of changing a posture and performing a work by moving a tool and a work at the same time in cooperation with each other. Take out the teaching data of
As a track between the teaching point, first calculating means for calculating the interpolation point representing the position and orientation of the workpiece relative to the position and orientation and a predetermined reference coordinate system of the tool relative to the workpiece, the word <br/> Current interpolation position base of tool position and orientation based on
A second calculating means for calculating a traveling vector from the vector and the previous interpolation position vector, and a tool based on the workpiece.
Use and the traveling vector and the position and orientation of Lumpur, tool
A third calculating means for calculating the position and orientation of the traveling coordinate system with reference to the above, a tool displacement related to the weaving amplitude and a tool position correction amount by the arc sensor, and a tool correction position calculated by the traveling coordinate system. Fourth calculating means, and the position and orientation of the tool with respect to the workpiece and the tool
Position and orientation of the traveling coordinate system based on
Fifth calculating means for calculating the position and orientation of the tool based on the work from the corrected position, and sixth calculation for calculating the operation amounts of the tool moving device and the work moving device based on the fifth calculation result And a driving means for simultaneously driving the tool moving device and the work moving device based on the sixth calculation result.