JP3070329B2 - Industrial robot system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial robot system for performing cooperative control and synchronous control between a plurality of manipulators.

[0002]

2. Description of the Related Art In recent years, industrial robots have become widespread in the welding industry, and demands for robots for more diverse and complicated workpieces have increased. In such an environment, when cooperative motion control between an industrial robot and a work mounting positioner or industrial robot is used from the viewpoint of easy robot posture for complex workpieces, improvement of welding quality, and reduction of jigs Is increasing.

[0003] This cooperative operation control is for controlling the operation of another robot as viewed from a work mounted on a positioner or gripped by a robot, and it is necessary to accurately define a relative position between the robots.

A means for defining a relative position between robots in a conventional industrial robot system will be described with reference to FIGS. FIG. 15 shows a robot 3 having six degrees of freedom.
FIG. 16 is a configuration diagram of an industrial robot system including a rotary positioner 32 having one and one degree of freedom and a control device 33 for controlling them.
And the rotational positioner 32. FIG.
As can be seen from FIG. 6, the relative position of the coordinate system Σ1 of the rotary positioner 32 with respect to the coordinate system （0 of the robot 31 is (L
x, Ly, Lz), and in a conventional system, this value is input and set in advance to the controller 33, and in order to eliminate an error between the input set value and the actual positional relationship,
Common base 34 for robot 31 and rotary positioner 32
It is common to position and install it exactly as set above.

[0005] The monitoring of the operating area of the conventional industrial robot system is defined in the reference coordinate system of the robot and is effective only when the operation program is operated.
Next, the operation means of the conventional industrial robot system when teaching cooperative operation will be described with reference to FIG. In FIG. 10, 35 is a robot having six degrees of freedom, 36 is a positioner having one degree of freedom having a rotation axis (not shown), and a tool 37 is attached to the tip of the robot 35.
In a conventional manual operation for performing a teaching operation on such a system, an operation mode for operating only the robot 35 or the positioner 36 and a positioner 36
Is operated, the tip point Q of the tool 37 and the vector t
And an operation mode in which the robot 35 performs a cooperative operation so that is held on the coordinate system # 1 of the positioner 36. That is, in the operation mode described later, the positioner 36
When the rotation axis is rotated by θ, the tool tip point Q moves to the position of Q ′ while maintaining the coordinate value on the と 共 に 1 coordinate system, and the robot 35 performs the following operation so that the tool vector t also becomes the vector t ′. Things.

Further, three manipulators (a robot 38, a positioner 39, and a positioner 4) as shown in FIG.
In the case of the industrial robot system consisting of 0), in the conventional cooperative operation, the cooperative operation of the robot 38 with only one of the positioner 39 and the positioner 40 is effective, and the other robot is synchronized only at the teaching point. The operation becomes synchronous.

[0007]

However, the conventional industrial robot system has the following problems. (1) First, in the relative position defining means, as described above, it is necessary to accurately position the robot on the common base according to the set value, and therefore, it is necessary to spend a great deal of time and effort on setup. Further, it is very difficult to eliminate the error at the time of installation, and the influence may cause the trajectory accuracy at the time of the cooperative operation to deteriorate.

The invention according to claims 1 and 2 of the present invention solves the above-mentioned problem, and provides an industrial robot system capable of defining a relative position between a plurality of manipulators in a short time and easily. For the purpose of providing,
Another object of the present invention is to provide an industrial robot system capable of further improving the accuracy of the relative position.

[0009]

Means for Solving the Problems (1) In order to achieve the above-mentioned object (the problem to be solved by the invention), the industrial robot system according to the first aspect of the present invention comprises:
Multiple obtained by teaching multiple times using a manipulator
From the teaching data of another manipulator coordinate system
A calculator for calculating the relative position and posture, and a storage unit for storing the calculated relative position and posture, control unit for performing cooperative control between the manipulator on the basis of the relative position and orientation
And at the time of the teaching, the first manipulator
Of the first manipulator of the tool attached to the
Control means is provided for constraining the posture viewed from the coordinate system to be constant .

[0010]

(1) The above (means for solving the problem) first
Since the relative position and posture between the manipulators can be calculated and defined by the teaching of the manipulators by having the means described in the section, the relative position and posture can be easily and accurately set in a short time. .

[0011]

(Embodiment 1) An embodiment of claims 1 and 2 of the present invention will be described below with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.

FIG. 1 is a perspective view of an industrial robot system to which the present invention is applied. This system includes a robot 1 having six degrees of freedom, a positioner 2 having one degree of rotation, and cooperative or synchronous control thereof. The robot 1 includes a control device 3 for performing teaching, and a teaching box 4 used for teaching. FIG. 2 shows the configuration of the control process. The controller 3 includes a relative position calculator 51 and a relative position storage 52
And an operation control unit 54 for performing a cooperative operation calculation and the like.

The teaching method for obtaining the relative position and orientation of the positioner 2 coordinate system ΔM2 viewed from the robot 1 coordinate system ΔM1 with reference to FIGS. 3 and 4 for the industrial robot system configured as described above. The means for calculating the relative position and orientation based on the teaching data obtained by teaching will be described. FIG. 3 is an enlarged view of a detailed portion of FIG. 1, and FIG. 4 shows a flow of the arithmetic processing. First, a rotary table 6 rotated by a rotary shaft 7 in the positioner 2
An arbitrary point P1 is determined above. At this time, the angle θ of the rotating shaft 7 is, for example, 0 °. By operating the teaching box 4 to operate the robot 1 to position the tip of the tool 5 at that point and storing the point P1, the coordinate value (x1, y1) of the point P1 represented in the coordinate system ΣM1 of the robot 1 is stored. ,
z1) can be obtained. Furthermore, the angle θ of the rotating shaft 7
Is rotated by an arbitrary angle θ1, the point P1 rotates to the position of P2, and by teaching this point P2 again by the robot 1, coordinate values (x2, y2, z2) can be obtained. Similarly, the point P3 obtained by rotating the rotating shaft 7 by θ2 is set to the robot 1
Coordinate values (x3, y3, z3)
Can be obtained. Since these three points are obtained by changing the angle of the rotation axis 7 to the same point, they exist on an arc with the rotation axis 7 as the center axis, and the three points P1, P2, P3 The coordinate value (x0, y0, z0) of the center point P0 expressed in the coordinate system ΣMI of the robot 1 can be easily obtained. That is, the coordinate value of the point P0 is a relative position of the coordinate center of the positioner 2 coordinate system ΣM2 with respect to the robot 1's coordinate system ΣM1. Therefore,

[0014]

(Equation 1)

The relative position between the two coordinate systems is obtained.
Next, the direction of each coordinate axis of the coordinate system ΣM2 of the positioner 2 viewed from the coordinate system ΣM1 of the robot 1 can be obtained by the following procedure. First, since the X 'axis can be arbitrarily set as long as it is perpendicular to the rotation axis 7 and on a plane including the point P0, the unit vector μ representing the axis direction with P0P1 as the X' axis is obtained by the following equation (2). Can be

[0016]

(Equation 2)

Since the Z 'axis indicates the direction of the rotation axis 7, the Z' axis is perpendicular to the arc plane including the three teaching points, and is expressed as the cross product of the vector P0P1 and the vector P0P2. That is, the unit vector ω representing the Z ′ axis direction is obtained by the following equation (3).

[0018]

(Equation 3)

Further, the unit vector を representing the direction of the Y ′ axis is obtained by the following equation (4) as a vector orthogonal to the previously obtained vectors μ and ω.

[0020]

(Equation 4)

From the above, the relative position and orientation of the coordinate system ΣM2 of the positioner 2 as viewed from the coordinate system ΣM1 of the robot 1 is P0 = (Lx, Ly, Lz).

[0022]

(Equation 5)

Can be obtained. With these values, the relational expression between the two coordinate systems is

[0024]

(Equation 6)

## EQU1 ## However, in the above equation (6), [X, Y, Z] is a coordinate value represented in the ΣM1 coordinate system, and [X ', Y', Z '] is a coordinate value represented in the ΣM2 coordinate system. By using this equation (6), coordinate conversion between the two coordinate systems can be performed, and arithmetic processing for cooperative operation control between the robot 1 and the positioner 2 can be performed.

Here, an example of an industrial robot system including two manipulators such as a robot 1 and a positioner 2 has been described. However, an industrial robot system including a plurality of manipulators such as a robot 12, a robot 13, and a positioner 14 as shown in FIG. For the robot system, the coordinate system of the robot 12 座標 M1
The relative position and posture of the robot 13 in the coordinate system ΣM13 and the relative position and posture of the positioner 14 in the coordinate system ΣM14 can be obtained.

As described above, since the relative position and orientation of the coordinate system between the manipulators can be obtained by the teaching operation of the manipulators and the calculation based on the teaching data, the installation state of each manipulator can be arbitrarily determined so as to be convenient for the operation. It can be installed and can be easily defined in a short time. (Example 2) The positioner 2 viewed from the coordinate system of the robot 1 in FIG.
Let us consider a case where the number of teaching points by the robot 1 for obtaining the relative position of the coordinate system is increased from three to four. The teaching procedure is the same as in the first embodiment. In this case, four points P1, P2, P3, and P4 on the same arc centered on the rotation axis 7 are obtained, and the coordinate values of three of these points are used to obtain the coordinates of the robot 1 at the center of the arc. The coordinate center of the viewed positioner 2 can be obtained. That is, four types of arc centers P01, P02, P03, P are determined by a combination of three of the four points.
04 can be requested. If there is no error in the teaching error or calculation error and the link parameter of the manipulator at the time of teaching, the coordinate values of these four points are equal. However, such a case is not usually considered, and the optimal value is calculated from the four coordinate values by the least square method. Can be requested. That is, the greater the number of teaching points, the more accurately the relative position between the robot 1 and the manipulator can be obtained.

Further, as shown in FIG. 6A, an error ΔR between the position R of the control point set in the control device of the robot 1 and the actual position R ′ of the tool tip due to an error of the tool 5 or the like. Consider the case in which In such a state, when the robot 1 is used to teach the relative position and orientation of the coordinate system of the positioner 2 based on the procedure shown in the first embodiment with three different tool postures, (FIG. 6) As shown in b), P1 ', P2', P
The coordinate value of 3 'is taken in, and P0' having an error with respect to the ideal relative position P0 is obtained as an operation result by the three points, and the direction of the error ΔR at the three points is different, so that the rotation axis is different. Also, the coordinate axis Z ′ representing 7 is obtained as Z ″ having an error, which causes an error in the trajectory during the cooperative operation. Therefore, as shown in FIG. 6, the first point P1 was taught. For the subsequent operation, there is provided a control means for restricting the posture of the tool 5 to the folding posture taught by P1 on the coordinate system of the robot 1. When three points are taught by using such a means, FIG. As shown in (c), the direction of the error ΔR at each point can be made the same, and an error is generated by ΔR at the relative position P0, but no error is generated at the coordinate axis Z ′ representing the rotation axis direction, Trajectory accuracy during cooperative movement Reference Example 1 Reference Example 1 of the present invention will be described with reference to FIG.
Denotes a processing unit according to the present invention when the relative position between the manipulators is changed, and a calculation unit 21 that calculates a conversion parameter from the relative position and posture data before and after the change, and a storage unit that stores the conversion parameter 22, an operation unit 23 for converting an existing teaching program according to the conversion parameters.

Hereinafter, the case where the relative position and orientation of the coordinate system of the robot 1 and the coordinate system of the positioner 2 are changed in the system shown in FIG. 1 will be described. First, it is assumed that the relative position and posture of the positioner 2 as viewed from the robot 1 before the change are obtained as follows by teaching three points by the means shown in the first embodiment. PO1 = (Lx1, Ly1, Lz1)

[0030]

(Equation 7)

In this state, when the installation state of the robot 1 and the positioner 2 is changed, the three points on the rotary table 6 taught before the change are re-taught so that the coordinate system of the robot 1 after the change is changed. Seen Positioner 2
Are obtained as follows.

Po2 = (Lx2, Ly2, Lz2)

[0033]

(Equation 8)

Based on the relative position and orientation before and after the change, the conversion parameter d for the position can be obtained from the difference between PO1 and PO2 by the following equation. d = (Lx2-Lx1, Ly2-Ly1, Lz2-Lz1) = ([Delta] Lx, [Delta] Ly, [Delta] Lz) The conversion parameter M21 for the posture can also be obtained from M1 and M2 by the following equation (9).

[0035]

(Equation 9)

When the cooperative work teaching program taught before the relative position change is desired to be used after the relative position change, it can be used without re-teaching by the following conversion procedure. The teaching program consists of a plurality of teaching points,
It is stored as the joint angle of the robot 1 and the positioner 2 at each teaching point. Therefore, first, the teaching point data expressed by the joint angle is converted into the coordinate values of the control points of the robot and the posture of the tool. For example, for a certain teaching point in a program, position data Pn = (Pnx, Pny, Pn
z) and 3 × 3 matrix Mtn which is tool posture data
Is converted to The position data and the posture data of the tool are converted into the post-change position data Pn 'and the posture data Mtn' of the tool as follows by the conversion parameters d and M12.

Pn '= d + Pn Mtn' = M2-1 ・ M1 ・ Mtn The position data Pn 'of the teaching point after the relative position change and the posture data Mtn' of the tool obtained from the above are converted into joint angles in reverse. By doing so, the changed teaching point data is obtained, and the above calculation is performed on all the teaching point data to obtain a teaching program corresponding to the relative position change. Reference Example 2 Reference Example 2 of the present invention will be described below with reference to FIG. FIG. 9 shows an industrial robot system to which the present invention is applied. 24 is a robot having six degrees of freedom, and 25 is a positioner having two degrees of freedom having rotation axes 28 and 29. In this system, the relative coordinate system ΣM2 of the positioner 25 from the coordinate system ΣM1 of the robot 24 is
It is defined by the means described in the first embodiment. In the present invention, each coordinate axis X′−
There is a means for inputting and setting an arbitrary offset value in the Y'-Z 'positive and negative directions. That is, lX1 for the X '(+) direction, lX2 for the X' (-) direction, ly1 for the Y '(+) direction, ly2 for the Y' (-) direction, and ly2 for the Z '(+) direction. By inputting and setting lZ2 in the lZ1 and Z '(-) directions, the area 27 can be defined on the relative coordinate system of the positioner 25. Since the area 27 is defined on the relative coordinate system as described above, for example, when the rotation axis 28 is rotated by α degrees, the area 27 is similarly rotated to the area 27 '. Further, it has a monitoring function for the set area, and when the tip of the tool 26 of the robot 24 enters the area 27 at the time of teaching,
The robot 24 is once stopped by the warning, and the speed of the robot 24 is limited in the area.

As is clear from the above description, by providing the above means, the area can be defined on the relative coordinate system. Therefore, the area changes according to the operation of the rotating axis, and the area monitoring of the robot can be performed effectively. Can be. Embodiment 3 Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 9 shows an operation mode of an operation mode at the time of teaching operation of the industrial robot system of the present invention. In the figure, 35 is a robot having 6 degrees of freedom, and 36 is a positioner having 1 degree of freedom having a rotation axis (not shown). And robot 3
A tool 37 is attached to the tip of the tool 5. FIG. 12 shows a configuration of operation mode switching. FIG.
As will be understood from the above description, in the present invention, three operation modes are provided so as to be selected at the time of the teaching operation using the teaching box 47, and each operation mode will be described below.

First, the operation mode 1 is an operation mode in which only the robot 35 or the positioner 36 is individually operated. As shown in FIG. 10, the operation mode 2 is an operation mode in which the robot 35 cooperates so that the tip point Q and the vector t of the tool 37 are held on the coordinate system # 1 of the positioner 36 when the positioner 36 is operated. It is.
That is, when the rotation axis of the positioner 36 is rotated by θ, the tool tip point Q moves to the position of Q ′ while holding the coordinate value on the Σ1 coordinate system, and the tool vector t becomes the vector t ′. Follow-up operation.

On the other hand, in the operation mode 3, as shown in FIG. 11, when the positioner 36 is operated, only the tip point Q of the tool 37 is held on the coordinate system # 1 of the positioner 36,
The vector t of the tool 37 is an operation mode in which the robot 35 cooperates so as to be held on the coordinate system # 0 of the robot 35. That is, when the rotation axis of the positioner 36 is rotated by θ, the tool tip point Q moves to the position of Q ′ while holding the coordinate value on the Σ1 coordinate system, but the tool vector t is held as the vector t. The robot 35 follows.

The switching between the three operation modes can be performed by operating keys arranged on the teaching box 47. Reference Example 4 Reference Example 4 of the present invention will be described with reference to FIG. FIG. 13 shows an industrial robot system to which the present invention is applied, wherein 38 is a robot having 6 degrees of freedom,
Reference numeral 39 denotes a positioner having two degrees of freedom, and reference numeral 40 denotes a positioner having one degree of freedom. FIG. 14 is a configuration diagram when the cooperative operation manipulator is switched. In the system shown in FIG. 13, the robot 38 and the positioner 39
With the robot 38 or the robot 38 and the positioner 40
The control device 56 has a cooperative operation group setting unit 58 in order to enable cooperative operation with the control device. In the cooperative operation group setting section 58, the above two cooperative operation groups are input and defined in advance. With this definition, the switching control unit 59 of the cooperative operation group is enabled, and the manipulator to be the cooperative operation at the time of teaching can be switched.

Further, the switching of the cooperative operation group can be performed by operating a key arranged on the teaching box 47.

[0043]

(1) As is clear from the first embodiment, there is provided an arithmetic unit for calculating the relative position and orientation between the coordinate systems of the manipulator from the teaching data obtained by teaching using the manipulator. Therefore, the relative position and orientation can be easily and accurately set in a short time.
Further, as is apparent from the second embodiment, the accuracy of the relative position and the attitude can be increased by increasing the number of teaching points for obtaining the relative position, or by having means for restraining the tool attitude during teaching.

[Brief description of the drawings]

FIG. 1 is a perspective view of an industrial robot system to which the present invention is applied.

FIG. 2 is a block diagram of a control process according to the first embodiment of the present invention.

FIG. 3 is an explanatory view of a teaching operation in the first embodiment.

FIG. 4 is a flowchart of a calculation process according to the first embodiment;

FIG. 5 is a perspective view of another industrial robot system to which the present invention is applied.

FIG. 6 is an operation explanatory diagram in the second embodiment.

FIG. 7 is a flowchart of a calculation process in the second embodiment.

FIG. 8 is a block diagram illustrating a calculation process according to the first reference example ;

FIG. 9 is a perspective view of an industrial robot system for explaining the principle in the second reference example .

FIG. 10 is a plan view 1 for describing an operation in an operation mode according to a third reference example ;

FIG. 11 is a plan view 2 for describing an operation in an operation mode according to a third reference example ;

FIG. 12 is a block diagram illustrating control processing according to a third reference example .

FIG. 13 is a perspective view of an industrial robot system to which the fourth reference example is applied.

FIG. 14 is a block diagram illustrating control processing in a fourth reference example .

FIG. 15 is a plan view of a conventional industrial robot system.

16 is a diagram showing a relative positional relationship between the manipulators shown in FIG.

[Explanation of symbols]

 1 Robot with 6 degrees of freedom 2 Positioner with 1 degree of freedom 3 Control device 4 Teaching box 5 Tool 6 Rotary table 7 Rotary axis

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B25J 9/10 B25J 9/22 B25J 13/00

Claims (3)

(57) [Claims] An industrial robot system comprising a plurality of manipulators and a control device for controlling, manipulating, storing, calculating and editing operation programs of the respective manipulators, and performing synchronous and cooperative operations between the manipulators . Teaching multiple times using one manipulator
From the multiple teaching data obtained by the
A computing unit that computes the relative position and orientation of the coordinate system of the purifier, a storage unit that stores the computed relative position and orientation, and a control unit that performs cooperative control between the manipulators based on the relative position and orientation. At the time of the teaching,
The second of the tools attached to the first manipulator;
The posture of the manipulator viewed from the coordinate system is fixed.
An industrial robot system provided with control means for bundling . 2. The arithmetic means for calculating the relative position and posture determines an arbitrary point on a rotating portion of another different manipulator having a rotating axis with respect to the installation portion or on a member attached to the rotating portion. By teaching one point three times with the first manipulator with the angle of the rotation axis being different, the relative position of the coordinate system of the other different manipulator viewed from the coordinate system of the first manipulator from three teaching data obtained. 2. The industrial robot system according to claim 1, wherein the calculating means is a calculating means for obtaining a position and a posture. 3. The relative position and orientation calculating means sets the number of teaching times to four or more, and obtains the different manipulators as viewed from the coordinate system of the first manipulator by the least square method from the obtained four or more teaching data. 2. A calculating means for calculating a relative position and a posture of a coordinate system.
The industrial robot system as described.