JPH0398786A - Interference checking method for industrial robot - Google Patents

Abstract

PURPOSE:To prevent a robot from creating interference even with wrong operation on the operator side by examining whether a manipulator enters into an interference region from functions indicating the previously obtained interference region and coordinates indicating the position of the manipulator. CONSTITUTION:Supposing the action range of a list 5 is made angles theta4=+ or -250 deg., theta5=+ or -270 deg., theta6=+ or -250 deg., the functions of borderlines a, b, c, d, e, f of the interference region are respectively indicated as expressions I-VI. In case the coordinate theta4 detected according to the position of a manipulator is outside the range of -270 deg.-+90 deg., 360 deg. is substracted from the coordinate theta4, thus adjusting its range. The range of the coordinate theta5 is adjusted in the same way. In case the coordinate theta4 is within the lines c, f, whether the coordinate theta5 is outside the lines a, d is judged, and if inside, whether the coordinates theta4, theta5 are outside the lines c, e are judged. If outside, non-interference is indicated, and if inside, entering into the interference region is indicated, thus limiting the action of a robot. The robot does not therefore create interference even with the wrong operation on the operator side.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an articulated industrial robot, and particularly to an interference checking method for an industrial robot, which is suitable for controlling the operation of a manipulator thereof.

"Conventional Technology" Some conventional industrial robots cause interference with the manipulator. For example, depending on the mechanism of the robot, when the wrist (wrist) of a manipulator is rotated, interference may occur between the wrist and the arm that supports it, making it impossible to rotate the wrist any further.

To prevent such interference, it is possible to limit the operating range of the manipulator, or, even if there is an interference area in a certain space within the operating range of the manipulator, no special restrictions are placed on control, and the robot operator make decisions and prevent interference from occurring.

"Problem that the invention attempts to solve" The above conventional technology has the following problems.

(1) If the mechanism is such that only the non-interference area is used as the operating area, the operating range will become unduly narrow.

(2) If there is an interference area within the operating range, the operator may accidentally interfere with the manibus during teaching.

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

(4) Since teaching can be performed even at the edge of interference, interference may occur during playback operation if a large margin is not allowed for the interference area during teaching.

"Means for Solving the Problems" In order to solve the above problems, the present invention detects an articulated robot manipulator and the coordinates representing the posture of the manipulator, and according to teaching points manually set in advance, a robot controller for controlling the manipulator, the manipulator body having a mechanism that can cause interference in a certain space within its operating range;
and an industrial robot configured such that the movement into the interference region cannot be mechanically restricted, from a function representing the interference region obtained in advance from the mechanism of the manipulator body and coordinates representing the posture of the manipulator, or From the function and the teaching point,
The method is characterized by comprising the steps of: checking whether the manipulator enters the interference region; and, if the manipulator enters the interference region, restricting its operation.

"Operation" According to this method, the interference region is first clarified from the mechanism of the manifold, and a function representing the interference region is determined. This function and the detected coordinates or the function and the teaching point are used to check whether there is interference of the robot manipulator and to restrict the movement of the robot manipulator to the interference area.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a perspective view showing the structure of a 6-axis vertically articulated industrial robot manipulator according to this embodiment. In the figure, on top of box l are a base 2, a first arm 3
is arranged, the second arm 4 is disposed on the l-th arm 3, and the second arm 4 is disposed on the l-th arm 3;
Resists 5 having a three-axis orthogonal offset (lemma) structure are rotatably connected to the arm 4.

The operating range of List 5 is θ4=±2500θ,=±2700θ based on the posture shown in FIG. 1±250
It is 0. Here, when the angles θ4 and θ of the wrist 5 are simultaneously moved (rotated) in the minus (-) direction, the wrist 5 and the second arm 4 interfere. In this mechanism, θ
The interference region becomes clear from the relationship between 4 and θ, and this is illustrated in FIG. 2.

Figure 2 shows the angle (operating range) of 04 on the horizontal axis and θ on the vertical axis.
, and shows the operating area and interference area. The functions of the boundaries a, b, c, d, e, and f of the interference area are a: θ, = 00 b 20, 110, respectively. - 1 1 0'C:
04=00d; θ. -180' e: θ,=-θ. -250'f: θ. It is expressed as -180'. This boundary line is used to check whether the manipulator has entered the interference region.

FIG. 3 shows an interference area check algorithm according to the first embodiment, in which the coordinates θ4, θ5 detected corresponding to the posture of the manipulator or the taught point coordinates θ4. θ
, perform the following operations.

In FIG. 3, both θ4 and θ return to the same posture after 3600 rotations, so the interference check can be performed within the 3600 rotation range. Therefore, θ4 and θ are both −270°
It is assumed that the range is checked in the range of ~+90'.

First, in steno knob P1, θ4 is -2700 to +9
Determine whether it is within the range of 0°. If it is outside the range, the process proceeds to step P2, and by subtracting 3600 from θ4, the range is changed to -2700 to +90'. Similarly, in step P3 and step P4, θ,
Adjust the range.

Next, the process proceeds to step P5, where it is determined whether θ4 is outside the lines C and f, and if it is outside, it is determined that there is no interference. On the other hand, if it is inside, the process advances to the next step P6, and it is determined whether θ is outside the lines a and d. If it is outside, there will be no interference. On the other hand, if it is inside, proceed to the next step P7,
It is determined whether θ4 and θ are outside the lines b and e. If it is on the outside, there is no interference, and if it is on the inside, an interference flag is set corresponding to θ4, θ, indicating that the interference region has been entered. Based on this flag, the robot control software limits the robot's movements.

Embodiment 2 Embodiment 1 described above can restrict the movement of the robot manipulator to the interference region. However, if an object such as a workpiece or a painting gun that is larger than the diameter of the wrist tip is gripped at the tip of the wrist 5, the interference area will expand, so interference checks must be performed accordingly. The second embodiment is provided with a function of changing the boundaries of the interference check algorithm in accordance with such changes in the interference area.

In the case of this embodiment, as shown in FIG.
, d may be changed depending on the size of the object held at the tip of the wrist 5, such as a workpiece or a painting gun, and if the amount of change is g, then the equation of the boundary line is as follows.

a: θ, = 0° 10g b. θ, 110. -110' C: 04=000g d: θs- 180' g e: θ,=-θ. −250° f: θ,=−180′ −g The interference area change amount g is determined by the size of the object held at the tip of the wrist 5, as shown in FIG.

Each straight line corresponding to each g indicates the allowable limit of the size of the held object when g is the value. Based on this diagram, the value of g is registered in advance in correspondence with the type number of the held object.

FIG. 6 shows the interference area check algorithm according to the second embodiment, in which coordinates θ4, θ, detected corresponding to the posture of the manipulator, or taught point coordinates θ4,
For θ, the following calculation is performed.

First, in the steno pen PlO, a table in which the interference area change amount g is registered in advance is searched using the type number of the object to be held, such as a workpiece or a coating gun, to find the value of g.

Next, in the same manner as in FIG. 3, the data of θ4 and θ are changed to the range of -270°+90° in steps Pll to P14. Then, in step P15, it is determined whether the values of θ4 and θ are outside the boundaries c and f changed by g. If it is outside/side, there is no interference. on the other hand,
If it is inside, the process proceeds to step P16, and it is determined whether the values of θ4, θ are outside the changed boundaries a and d.

If it is outside, there is no interference. On the other hand, if it is inside, the process advances to step P17 and θ is determined. It is determined whether the value of θ is outside the boundaries b and e. If it is outside, there is no interference. On the other hand, if it is inside, proceed to step P18. Set the interference flag to θ.
. Set corresponding to θ.

"Effects of the Invention" As explained above, according to the present invention, an algorithm for checking whether or not the robot machine interferes is incorporated, so that the following effects can be obtained.

(1) The posture that the operator attempts to advance during teaching is sequentially checked, and if there is interference, the robot is controlled so that it cannot advance any further. This prevents the robot from interfering even if the operator makes a mistake.

(2) When the taught program is changed using data conversion functions (shift conversion, mirror image conversion, axis shift conversion, etc.), the robot will function normally without interference even if the robot is not actually moved. You can check whether it works or not.

(3) Even if a program that causes interference is accidentally played back, the robot can be stopped before the interference occurs.

(4) By providing a function to change the interference area, even if, for example, a teaching program that carries workpiece A carries workpiece B, workpiece B and the arm will interfere, the presence or absence of interference can be detected. Since it can be checked in advance, interference can be prevented.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the structure of a manipulator of an industrial robot according to an embodiment of the present invention, and FIG.
) and the fifth axis (θ5), FIG. 3 is a graph showing the interference check algorithm of Example 1, and FIG. 4 is a graph showing the relationship between the fourth axis (θ4).
) and the fifth axis (θ5), a graph showing the operating region and interference region of Example 2, FIG. 5 shows the interference region change m
FIG. 6 is a diagram showing the relationship between (g) and the size of an object that can be gripped at the tip, and FIG. 6 is a diagram showing the interference chienoqualorism of Example 2. ■・・・Box, 2・・・Base, 3・
...First arm, 4...Second arm, 5
...List, θ4...Rotation angle of the 4th lift, θ5...Rotation angle of the 5th axis, θ6...
・Rotation angle of the 6th axis, a, b, c, d, e, f...
... Interference area boundary line, g... Interference area change amount (
angle).

Claims (2)

[Claims] (1) It has an articulated robot manipulator and a robot controller that controls the manipulator according to teaching points input in advance while detecting coordinates representing the posture of the manipulator, and the manipulator main body controls the operation of the manipulator. In an industrial robot that has a mechanism that can cause interference in a certain space within its range, and is configured such that its movement into the interference area cannot be mechanically restricted,
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, or from the function and the teaching point,
A method for checking interference in an industrial robot, comprising the steps of: checking whether the manipulator enters the interference region; and, if the manipulator enters the interference region, restricting its operation. (2) In the interference checking method for an industrial robot according to claim 1, a workpiece to be gripped at the tip of the manipulator;
A method for checking interference in an industrial robot, characterized in that the function is changed according to the size of a gripped object such as a painting gun, and the presence or absence of the interference is checked using the changed function.