JP2597979B2 - Robot control data interference check method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION The present invention relates to, for example, glass cutting of steel materials.
The present invention relates to a method for performing an interference check of robot control data in a case where work whose contents are different each time is performed using an articulated robot.

2. Description of the Related Art Conventionally, an operator teaches control data relating to a position and a posture with respect to a robot by directly guiding an arm of the robot to each point required for work using a teaching box. This teaching is performed in an actual working environment, and it is visually confirmed that the robot can operate without interfering with objects existing around the robot while operating the robot according to the taught data. I have confirmed.

Problems to be Solved by the Invention In the above-described conventional method, as described above, in order to confirm the validity of the robot control data, the robot is operated according to the data in an actual work environment. Let me. Therefore, when the robot operation is different every time, a lot of time is required for confirmation each time.
While the control data is being checked, the robot cannot be operated to perform the actual work, so that the operation rate of the production line including the robot is reduced.

In order to solve such a problem, for example, “Operation command to robot and its realization” (“Mathematical Science” No.249, 1
(Published March 984, pp. 17-24), although the concept of so-called offline teaching has been announced, it has been recognized that the technical content is sufficiently demonstrated. Therefore, the above problem cannot be solved.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method capable of solving the above-mentioned problems and performing an interference check of robot control data without directly operating an articulated robot.

Means for Solving the Problems The present invention relates to an interference check of robot control data for an operation of performing machining while moving between teaching points using such a tool 2, which is rotationally symmetric about the axis of the tool 2. In the method, the tip position of the tool in the workpiece coordinate system Σw corresponding to one teaching point and the posture (xw, yw,
zw, αw, βw, γw) and a tool position / posture vector determined by the input (xw, yw, xw, αw, βw, γw) Is the position / posture vector in the robot coordinate system Σr And the rotation amount θi (i
= 1 to 6), a third step for checking whether or not the rotation amount θi of each joint falls within the structural operation range of each joint, and a hand unit 15 of the robot body 14 having six degrees of freedom. A plurality of points P1 to P8 on the outer shape of are defined, and coordinates (xrj, yrj, zrj) of these points P1 to P8 in the robot coordinate system Σr (where j = 1 to
8), and the object 13 around the robot in the robot coordinate system Σr is spatially occupied when one axis Y in the robot coordinate system Σr and one axis X in the workpiece coordinate system Σw are parallel. The convex interference region 19 is defined by a plurality of line segments
And the equation z = g (x) in the robot coordinate system Σr of the segments 17 and 18 where g (x) is a function of x and a function independent of the value of y Then, the coordinate values of the robot coordinate system Σr of the plurality of points P1 to P8 on the outer shape of the hand unit 15 are substituted into the left side and the right side of the equation, respectively, and the magnitudes of the left and right sides are compared. Hand part
It is checked whether or not the object 15 exists in the convex interference area 19 of the object 13, and a fifth step for determining the presence or absence of interference, and the positions and postures of the tool 2 are determined by the first to fifth steps. A sixth step to be executed for the next teaching point, and a position and orientation in the middle between the two teaching points in which the position and orientation of the tool 2 are determined are obtained by interpolation calculation, and A robot control data interference checking method, comprising: a seventh step of executing five steps.

According to the present invention, a plurality of points P1 to P8 on the outer shape of the hand unit 15 of the six-degree-of-freedom robot body 14 at one teaching point are determined, coordinates in the robot coordinate system Δr are obtained, and coordinates in the robot coordinate system Δr are determined. The convex interference region 19 occupied by the object 13 around the robot is spatially approximated by a plurality of line segments 17 and 18 to obtain each expression by an equation. At this time, one axis Y and the workpiece coordinate in the robot coordinate system Σr are obtained. One axis X in the system Σw is parallel, whereby the object
13 is approximated by a plane, and the calculation of the interference check can be easily performed. The coordinates of each of the points P1 to P8 are substituted into each expression by such an equation, and the magnitudes of the left and right sides are compared.

Further, according to the present invention, the interference is checked by executing the first to fifth steps for the next teaching point in which the position and the posture of the tool 2 are determined, and the position and the halfway between the teaching points are checked. The posture is interpolated to check for interference during operation between two points.

Embodiment FIG. 1 is a block diagram showing a configuration of a control data confirmation device for an articulated robot according to an embodiment of the present invention. The control device (xw, yw, zw, αw, βw, γw) describing information on the position and orientation of the tool described later in the work coordinate system Σw is transmitted from the input device 3 to the confirmation device 4. Is entered.

The coordinate exchange device 5 converts the control data described in the work coordinate system Σw into control data (xr, yr, zr, αr, βr, γr) described in the robot coordinate system Σr described later. The output from the coordinate conversion device 5 is provided to a joint angle displacement calculation device 6 that calculates the amount of angular displacement of the joint as an axis value.
The output from the joint angle displacement calculating device 6 is provided to a checking device 7. The checking device 7 includes an operating range checking device 8 and an interference checking device 9, and the checking is performed by the checking devices 8 and 9 in this order.

The display device 11 to which the output of the check device 7 is input displays whether or not the robot control data input from the input device 3 is appropriate.

When it is determined by the check device 7 that the input robot control data is appropriate, a signal from the input device 3 is input to the robot drive device 12 to drive the robot.

FIG. 2 is a perspective view showing the work coordinate system Σw in the work target object 13, and FIG. 3 is a diagram for explaining the expression of the position and orientation of the tool 2 in the work coordinate system Σw. As shown in FIG. 2, a work coordinate system Σw including three mutually orthogonal coordinate axes Xw, Yw, Zw is set for the work object 13. As shown in FIG. 3, data on the position and orientation of the tool 2 is set in the workpiece coordinate system Σw.
That is, the position is represented by coordinates (x, y, z) of the tip position of the tool 2, and the posture is represented by Euler angles (α, β, γ). At this time, a position / posture vector representing the position and posture of the tool 2 Is a six-component vector composed of a three-component vector representing a position and a three-component vector of an Eulerian angle representing a posture. If the position vector is the origin movement and the posture expressed by the Euler angle is represented by a rotation matrix, the position / posture vector Can be converted into the following 4 × 4 position / posture matrix T. vector The transformation and inverse transformation to matrix T from each f, f ^-1
Expressed by

Here, S is the tool 2 from the workpiece coordinate system Σw shown in FIG.
Is a three-row, three-column coordinate rotation matrix in the tool coordinate system Σt composed of three mutually orthogonal coordinate axes Xt, Yt, Zt set in, and each element is a function of α, β, γ Each is represented.

The position of the tool 2 expressed in the workpiece coordinate system Σw
Posture vector Position / posture vector in a robot coordinate system Σr composed of three mutually orthogonal coordinate axes Xr, Yr, Zr, which will be described later. Is converted by the third equation.

Position / posture vector in robot coordinate system Σr Is in absolute coordinate system And the position / posture vector in the workpiece coordinate system Σw Is in absolute coordinate system Becomes This matches, so Therefore, Here, Tw and Tr are coordinate transformation matrices from the work coordinate system Σw and the robot coordinate system Σr to the absolute coordinate system Σo, respectively, as described later.

FIG. 4 is a perspective view showing the relationship between the workpiece coordinate system Σw, the robot coordinate system Σr, and the absolute coordinate system Σo. A work coordinate system 座標 w and a robot coordinate system Σr for the work object 13 are set for an absolute coordinate system Σo composed of three mutually orthogonal coordinate axes X, Y, and Z.

FIG. 5 is a perspective view showing a model of a robot mechanism according to an embodiment of the present invention. In this embodiment, a plurality of links L1 to L5 are used. Each of these links L1 ~
A coordinate system Σi (i = 1 to 6) including three mutually orthogonal coordinate axes Xi, Yi, Zi is set in L5. The end of each link is a joint, and the rotation amount of each joint is θi
(I = 1 to 6). The position / posture vector is determined based on the robot mechanism and the shape of the tool and the mounting method thereof. The joint angular displacement vector θ = (θ1, θ2, θ3, θ4, θ5, with the angular displacement θi (i = 1 to 6) of each joint as an element
θ6) can be obtained. Therefore, the angular displacement θ
By checking whether or not i falls within the structural operation range of each joint, the position / posture vector of the tool input from the input device 3 is checked. Can be checked for feasibility and thus the first
The check function is performed. The above-mentioned structural operation range of each joint means a range of mechanical stroke that can be taken as each axis value for each joint of the robot body, and the position / posture vector Is satisfied, the angular displacement θi of each joint is within the operating range ai <θ
It is checked whether or not i <bi (i = 1 to 6) is satisfied. Generally speaking, the robot is configured so that the arms do not collide with each other, and thus checking whether or not the arms fall within the motion range includes the limitation of the motion range resulting from the avoidance of the collision between the arms and the like. Not something.

The interference check function, which is a second check function implemented in the present invention, is a function that calculates a spatially occupied portion of the robot body when the robot is in a posture determined by the angular displacement vector Θ. Spatial parts,
This is a function for verifying whether or not a peripheral portion such as an obstacle occupies a space. This function will be described below.

FIG. 6 is a diagram showing the shape of the robot main body 14 of the articulated robot 1 and the objects around it, and FIG. 7 is a diagram for explaining a method of checking the interference between the robot and the work object 13. Referring to FIG. 6, the hand portion of the robot body 14
15 is, for example, columnar, and the work target portion 13 is, for example, prismatic. Therefore, as shown in FIG. 7, the cylindrical hand portion 15 is approximated by a plurality of (eight in this embodiment) points P1 to P8 on the circumference of the bottom surface 16 thereof.

Also, the Y axis of the robot coordinate system Σr and the work coordinate system Σw
Is assumed to be parallel to the X axis of
Can be approximated by two line segments 17, 18 as shown in FIG. Regarding the two line segments 17 and 18, it is verified that the hatched area 19 formed on the opposite side to the hand unit 15 is the convex interference area, and that the point corresponding to the robot does not fall within the interference area 19. I do. This verification is performed as follows.

A 部 6 coordinate system (see FIG. 5) is set in the hand unit 15 of the articulated robot 1, and in FIG.
Each approximation point Pj (xj, yj, zj) (j = 1 to
8) is defined in this # 6 coordinate system. This approximate point Pj
(Xj, yj, zj) in the robot coordinate system Σr (x1j,
y1j, z1j) is obtained by the following equation.

Here, the matrix Ti (i = 1 to 6) is obtained from {i coordinate system}
_This is a coordinate exchange matrix for the _i-1 coordinate system, where 意味 0 means the robot coordinate system Σr. The matrix Ti is a transformation matrix for the components of the vector (point coordinates).

On the other hand, as shown in FIG. 7, the expression of the line segment 17 corresponding to the boundary of the work target object 13 in the robot coordinate system Σr is z =
Assuming that a is ax + b and does not depend on the value of y, it can be determined that no interference occurs as long as the condition represented by the following equation is satisfied.

a · x1j + b> z1j (5) Similarly, the interference check can be performed on the line segment 18 corresponding to the boundary of the work object 13.

Position / posture vector of tool 2 input as described above However, interference between a robot that realizes the above and obstacles around the robot can be verified. Further, the position and orientation of the tool 2 are determined in the middle of the two teaching points, and the position and orientation in the middle are obtained by an interpolation calculation, thereby confirming the above-described operation during the operation between the two points. Can be performed similarly.

Effects As described above, according to the present invention, a plurality of points P1 on the outer shape at each teaching point of the hand unit 15 of the six-degrees-of-freedom robot body 14 using such a tool 2, which is rotationally symmetrical about the axis of the tool 2. ~ P8, determine the coordinates in the robot coordinate system Σr, and approximate the convex interference region 19 occupied by the object 13 around the robot spatially with a plurality of boundary line segments 17,18 to form an equation. Since the coordinates of the points P1 to P8 are substituted into the expression of the equation to compare the magnitudes of the left and right sides, the calculation of the interference check is easy, and the interference can be checked easily and strictly. Become like

In particular, according to the present invention, 1 in the robot coordinate system Σr
Since the two axes Y and one axis X in the workpiece coordinate system Σw are parallel, the convex interference area 19 can be approximated not by a plurality of planes of the boundary but by line segments 17 and 18, Accordingly, an excellent effect that the comparison operation of the left and right sides by the above equation is extremely easy is achieved.

Further, according to the present invention, the position and posture of the tool 2 accompanying the movement of the hand unit 15 are executed for each teaching point in which the position and posture of the tool 2 are determined to check for interference, and the position and posture of the tool 2 are further determined. The positions and orientations in the middle of the two teaching points are obtained by interpolation and the first to fifth steps are executed, so that the interference check accompanying the movement of the tool 2 can be performed even more reliably. The excellent effect that can be achieved is also achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an articulated robot control data confirmation device 4 according to one embodiment of the present invention, FIG. 2 is a perspective view showing a work coordinate system .DELTA.w in a work object 13, and FIG.
FIG. 4 is a perspective view for explaining the representation of the position and orientation of the tool 2 using the workpiece coordinate system 、 w. FIG. 4 is a diagram showing the relationship between the workpiece coordinate system Σw and the robot coordinate system Σr. FIG. 6 is a diagram schematically showing the configuration of the shaft, FIG. 6 is a diagram showing the relationship between the articulated robot 1 and the work object 13, and FIG. 7 is a diagram for explaining an interference checking method between the hand unit 15 and the work object 13. FIG. 1 ... articulated robot, 2 ... tool, 4 ... confirmation device,
5 ... coordinate exchange device, 6 ... joint angular displacement calculation device, 7 ...
... Check device, 8 ... Operation range check device, 9 ...
Interference check device, 13 ... Work object, 14 ... Robot body, 15 ... Hand unit

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Katsuhiro Iwami 1-1, Kawasaki-cho, Akashi-shi Inside the Akashi Plant of Kawasaki Heavy Industries, Ltd. (56) References JP-A-60-16385 (JP, A) JP-A-59- 183408 (JP, A) JP-A-59-110581 (JP, A) JP-A-59-73289 (JP, A) JP-A-58-77490 (JP, A) JP-A-59-205284 (JP, A)

Claims (1)

(57) [Claims] 1. A method of checking robot control data for an operation in which machining is performed while moving between teaching points using such a tool 2, which is rotationally symmetrical about the axis of the tool 2, comprising: Of the tool in the workpiece coordinate system 先端 w and the posture (xw, yw, z
w, αw, βw, γw) and a position / posture vector of the tool determined by the input (xw, yw, xw, αw, βw, γw) Is the position / posture vector in the robot coordinate system Σr And the rotation amount θi (i
= 1 to 6), a third step for checking whether or not the rotation amount θi of each joint falls within the structural operation range of each joint, and a hand unit 15 of the robot body 14 having six degrees of freedom. A plurality of points P1 to P8 on the outline of the robot are defined, and the robot coordinate system の of these points P1 to P8
coordinates at r (xrj, yrj, zrj) (j = 1-8)
And a convex interference spatially occupied by the object 13 around the robot in the robot coordinate system Σr when one axis Y in the robot coordinate system Σr and one axis X in the workpiece coordinate system Σw are parallel to each other. The area 19 is approximated by a plurality of line segments 17 and 18 of the boundary, and the equation z = g (x) in the robot coordinate system Σr of the line segments 17 and 18 (where g (x) is a function of x Then, the coordinate value of the robot coordinate system Σr of the plurality of points P1 to P8 on the outer shape of the hand unit 15 is substituted into the left side and the right side of the above equation, respectively. And compare the values on both the left and right sides
It is checked whether or not the object 15 exists in the convex interference area 19 of the object 13 and a fifth step for determining the presence or absence of interference, and the position and posture of the tool 2 are determined in the first to fifth steps. A sixth step to be executed for the next teaching point, and a position and orientation in the middle between the two teaching points in which the position and orientation of the tool 2 are determined are obtained by interpolation, and the first
And a seventh step for executing a fifth step. The method for checking robot control data interference, the method comprising: