JP2763613B2 - Industrial robot interference check method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial robot, and more particularly, to an industrial robot interference check method suitable for controlling the operation of a manipulator.

"Conventional technology" In some conventional industrial robots, manipulators cause interference. For example, depending on the mechanism of the robot, when the wrist (wrist) of the manipulator is rotated, interference occurs between the wrist and an arm supporting the wrist, and the wrist cannot be further rotated.

In order to prevent such interference, the operation range of the manipulator is limited, or even if there is an interference area in a certain space in the operation range of the manipulator, no special restriction is imposed on control, and the robot operator does not Judgment is made to prevent interference.

"Problem to be Solved by the Invention" The above-mentioned conventional technology has the following problems.

(1) When a mechanism is used in which only the non-interference area is set as the operation area, the operation range is unduly obstructed.

(2) If there is an interference area within the operation range, the operator may erroneously interfere the manipulator during teaching.

(3) Even a correctly created teaching program may be converted into an interfering teaching program when converted using a data conversion function (shift conversion, mirror image conversion, etc.).

(4) Since the teaching can be performed at the very last place of the interference, if there is not enough room for the interference area at the time of the teaching, interference may occur during the reproducing operation.

“Means for Solving the Problems” In order to solve the above problems, the present invention provides a multi-joint type manipulator body and a teaching point input in advance while detecting coordinates representing the attitude of the manipulator body. Therefore, it has a robot controller that controls the manipulator body, and the manipulator body has
In an industrial robot having a mechanism capable of causing interference in a certain space within the operation range, a function representing the interference region obtained in advance from a mechanism of the manipulator body and coordinates representing a posture of the manipulator body, or the function And from the teaching point, a step of examining whether or not the manipulator body enters the interference area; and, if the manipulator body enters the interference area,
And limiting the operation. The function representing the interference region includes a function in which at least two axes of the manipulator body are variables.

According to this method, first, an interference region is clarified from the manipulator mechanism, and a function representing the interference region is obtained. Using this function and the detected coordinates, or the function and the teaching point, the presence or absence of interference of the robot manipulator is checked, and the operation of the robot manipulator to the interference area is limited.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG. 1 is a perspective view showing a configuration of a six-axis vertical articulated industrial robot manipulator according to this embodiment. In the figure, a base 2 and a first arm 3 are arranged on a box 1, and a second arm 4 is
A wrist 5 having a three-axis orthogonal offset (lemma) structure is rotatably connected to the arm 4.

The operation range of this list 5 is θ ₄ = ± 250 °, θ ₅ = ± 270 °, and θ ₆ = ± 250 ° based on the posture in FIG. Here, when the angles θ ₄ and θ ₅ of the list 5 are simultaneously moved (rotated) in the minus (−) direction, the list 5
And the second arm 4 interfere with each other. In this mechanism, θ ₄
An interference area from the relationship between theta ₅ becomes clear, when illustrate this is as Figure 2.

FIG. 2 shows an operation area and an interference area by taking an angle (operation range) of θ _{4 on} the horizontal axis and θ _{5 on} the vertical axis. The functions of the boundary lines a, b, c, d, e, and f of the interference area are a: θ ₅ = 0 ° b: θ ₅ = −θ ₄ −110 ° c: θ ₄ = 0 ° d: θ ₅ = −180 ° e: θ ₅ = −θ ₄ −250 ° f: θ ₄ = −180 ° Here, as described above, the boundaries b and e are
In both cases, the angles of the two axes θ ₄ and θ ₅ are used as variables and are expressed as functions. Using the above boundary line, it is checked whether the manipulator has entered the interference area.

FIG. 3 shows an interference area check algorithm according to the first embodiment, in which coordinates θ ₄ , θ ₅ or teaching point coordinates θ ₄ , θ ₅ detected corresponding to the attitude of the manipulator.
, The following operation is performed.

In FIG. 3, since both θ ₄ and θ ₅ return to the same posture when rotated by 360 °, the interference check may be performed within a range of 360 °. Therefore, both θ ₄ and θ ₅ are checked in the range of -270 ° to + 90 °.

First, in step P1, theta ₄ determines whether the -270 ° to + 90 ° range. If out of range,
The process proceeds to step P2, changing from theta ₄ to -270 ° to + 90 ° range by subtracting 360 °. Similarly, step P
3, and in step P4, to adjust the range of theta _5.

The flow advances to step P5, theta ₄ it is determined whether the outer line c, the line f, and without interference if the outside. on the other hand,
If inner proceeds to step P6, theta ₅ determines whether the outer line a, line d. No interference if outside. On the other hand, if it is inside, go to the next step P7, θ ₄ , θ ₅
Is outside the lines b and e. If it is outside, it is determined that there is no interference, and if it is inside, an interference flag indicating that it has entered the interference area is set in correspondence with θ ₄ and θ ₅ .
Based on this flag, the robot control software
Limit the movement of the robot.

Second Embodiment In the first embodiment, the operation of the robot manipulator to the interference area can be restricted. However, if a gripper such as a work or a paint gun that is larger than the wrist tip diameter is gripped at the tip of the wrist 5, the interference area is widened, and an interference check must be performed accordingly. Example 2
A function is provided for changing the boundary of the interference check algorithm in accordance with such a change in the interference area.

In the case of the present embodiment, as shown in FIG.
May be changed according to the size of a workpiece to be gripped at the tip of the wrist 5 or a gripping object such as a paint gun.
Then, the boundary line equation is as follows.

a: θ ₅ = 0 ° _{+ g b: θ 5 = -θ} 4 -110 DEG c: θ ₄ = 0 ° + g d: θ ₅ = -180 ° _{-g e: θ 5 = -θ 4} -250 ° f: θ ₄ = −180 ° −g The interference area change amount g is, as shown in FIG.
It is determined by the size of the object to be gripped at the tip. Each straight line corresponding to each g indicates the allowable limit of the size of the grasped object when g is that value. Based on this figure, the value of g is registered in advance in association with the type number of the gripped object.

FIG. 6 shows an interference area check algorithm according to the second embodiment, in which coordinates θ ₄ , θ ₅ or teaching point coordinates θ ₄ , θ ₅ detected corresponding to the attitude of the manipulator.
, The following operation is performed.

First, in step P10, a table in which the interference area change amount g is registered in advance by using the type number of the object to be gripped such as a work or a paint gun is searched, and the value of g is obtained.
Next, similarly to FIG. 3, steps P11 to P14
To change the data of θ ₄ and θ _{5 to} the range of -270 ° + 90 °. Then, in step P15, it is determined whether or not the values of θ ₄ and θ ₅ are outside the boundary lines c and f changed by g.
No interference if outside. On the other hand, if inside, step
Proceeding to P16, it is determined whether the values of θ ₄ and θ ₅ are outside the changed boundary lines a and d. No interference if outside.
On the other hand, if inside, proceed to Step P17. It is determined whether the values of θ ₄ and θ ₅ are outside the boundaries b and e. No interference if outside. On the other hand, if it is inside, the process proceeds to step P18, and the interference flag is set in correspondence with θ ₄ and θ ₅ .

"Effects of the Invention" As described above, according to the present invention, an algorithm for checking whether or not the robot manipulator interferes is incorporated, and therefore, the following effects can be obtained.

(1) At the time of teaching, the posture that the operator intends to advance is sequentially examined, and if there is interference, control is performed so that the robot cannot proceed further. As a result, the robot does not cause interference even if the operator makes an erroneous operation.

(2) When the taught program is changed using the data conversion function (shift conversion, mirror image conversion, axis shift conversion, etc.), it does not cause interference even if you do not actually move the robot. It can be checked whether or not it works.

(3) Even if a program causing interference is reproduced by mistake, the robot can be stopped before the interference.

(4) By providing the function of changing the interference area, for example, a teaching program carrying a work A
When the work is carried, even if the work B and the arm interfere, the presence or absence of the interference can be checked in advance, so that the interference can be prevented beforehand.

In addition, since the function representing the interference area includes a function in which at least two axes of the manipulator are used as variables, the interference area can be determined more precisely, and the interference does not actually occur. It is possible to minimize an area that is regarded as an area.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a manipulator of an industrial robot according to an embodiment of the present invention, and FIG. 2 is an operation of the first embodiment based on a relationship between a fourth axis (θ ₄ ) and a fifth axis (θ ₅ ). FIG. 3 is a graph showing an area and an interference area, and FIG.
FIG. 4 is a graph showing an operation area and an interference area according to the second embodiment based on a relationship between a fourth axis (θ ₄ ) and a fifth axis (θ ₅ ), and FIG. 5 is an interference area. FIG. 6 is a diagram showing the relationship between the change amount (g) and the size of the object that can be gripped at the tip, and FIG. 6 is a diagram showing an interference check algorithm according to the second embodiment. 1 ... box, 2 ... base, 3 ... first arm, 4
... Second arm, 5... List, θ ₄ ... Fourth axis rotation angle, θ ₅ ... Fifth axis rotation angle, θ ₆ ... Sixth axis rotation angle, a, b, c, d, e, f... interference area boundary line, g... interference area change amount (angle).

Claims (2)

(57) [Claims] An articulated manipulator main body, and a robot controller that controls the manipulator main body in accordance with a pre-input teaching point while detecting coordinates representing the attitude of the manipulator main body. In an industrial robot having a mechanism in which the main body has a mechanism capable of causing interference in a certain space within its operation range, from a function representing the interference region obtained in advance from the mechanism of the manipulator body and coordinates representing the attitude of the manipulator body, Or, from the function and the teaching point, a step of checking whether the manipulator body enters the interference area, and, if the manipulator body enters the interference area, a step of restricting the operation, The function representing the interference area is at least two axes of the manipulator body. An interference checking method for an industrial robot, comprising a function in which an angle is a variable. 2. The method for checking interference of an industrial robot according to claim 1, wherein said function is changed in accordance with the size of a gripping object such as a work or a paint gun gripped at the tip of the manipulator, and the function after the change is changed. An interference checking method for an industrial robot, wherein the presence or absence of the interference is checked.