JPH0994783A - Multi-robot system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a mutual collision between movable parts in a robot by deciding a robot occupied quadrant including an arm and a working head while setting a present position or a motion position as a center and determining a collision condition between respective robots on the basis of the robot occupied quadrant. SOLUTION: A robot, in which right hand group SCARA robots 19A, 19B are paired with left hand group SCARA robots 19C, 19D, is used, and in a working area 29, a lateral dimension is L while a longitudinal dimension is M, and then, a working area home position (0, 0) is located on a of side of the left hand group robot 19B when the working area 29 is represented by the X-axis and the Y-axis. Respective working heads used for an inspection of a printed circuit board are movable freely, and if probe heads in the four corners point the same point, a collision will happen, however, if each of the respective robots is stored within each quadrant when the working area 29 is divided into four quadrants while using the pointed point as a home position under this condition, it is determined that the four robots do not interfere with each other because each point pin has a clearance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot used for inspecting a printed circuit board, mounting parts on the printed circuit board, assembling an electronic device, and the like, and more particularly to a robot system for synchronously controlling a plurality of robots. It is about.

[0002]

2. Description of the Related Art Conventionally, when a plurality of robots operate in a certain area at the same time, for example, Japanese Patent Application No. 6-16252.
The collision between robots is prevented by the method disclosed in the publication.

That is, as shown in FIGS. 16 and 17, this is a horizontal articulated robot having a basic structure of a pair of arms provided on a base 50, and the structure is a base 50 and a pair of arms 51A. 51B, work heads 52A and 52B, and a control unit 53.

[0004] The base 50 includes a pair of arms 51A, 51A.
B, the first rotating motors 54A, 54A,
4B and gear boxes 55A and 55B.

[0005] The arms 51A and 51B are connected to a first arm 56 rotatably connected to the base 50 so as to be rotatable in the horizontal direction.
A, 56B and second arms 57A, 57B rotatable in the horizontal direction via the first arms 56A, 56B.

The working heads 52A, 52B are provided at the distal ends of the second arms 57A, 57B.
A and 57B are engaged with and locked to rotating shafts 58A and 58B that extend vertically downward with respect to the upper and lower ends.
A, 59B.

Here, the tip pins 59A, 59B are disposed with their axes shifted from the rotating shafts 58A, 58B, and when the rotating shafts 58A, 58B rotate on the object, the tip pins 59A, 59B are rotated. The tip of 59B has a structure that draws a locus of a circle.

Thus, for example, a pair of arms 5
Working heads 52A, 52 provided at the tips of 1A, 51B
When B faces each other, the position where the tips of the tip pins 59A and 59B point to one point is a distance where collision does not occur.

The motion loci of the work heads 52A and 52B in the horizontal articulated robot having such a structure are as follows.
First arm 56A, 56B and second arm 57A, 57
The first arm 56A, 56B and the second arm 57A, 57B are rotated while B moves in the horizontal direction to adjust the distance from the base unit 50. Then, the rotary shafts 58A and 58B can be appropriately rotated to move in a desired position direction. For details, refer to the above publication.

On the other hand, a pair of arms 51A, 51B and 5
As shown in FIG. 17, the articulated robot consisting of 1C and 51D is provided facing each other at opposing positions, and the control unit 53 controls the rotation amount of each arm 51A, 51B, 51C, and 51D to perform each work. Heads 52A, 52B, 52C,
52D is designed not to collide.

That is, one control unit controls the rotation of the motors that drive the respective arms of the robot, thereby limiting the movable range of each arm and avoiding collision between the arms operating in a certain area. There is.

In addition to the above methods, various methods for avoiding collision of robots have been proposed.

For example, in the method disclosed in Japanese Patent Laid-Open No. 59-129691, the same work area overlapping between a plurality of robots is defined in advance as an interference area,
Whether or not the robot exists in the interference area is determined based on the image information sent from the visual device provided above every moment. Then, when the robot exists, in order to prevent the other robot from entering the interference area, a signal to that effect is output to the other robot. On the other hand, when it is detected by the visual information sent from the visual device that the robot has exited the interference area, another signal is sent to the other robot so that the other robot enters the interference area. It becomes possible to do.

Further, in the method disclosed in Japanese Patent Application Laid-Open No. 4-19084, a collision is prevented by determining the operation area of the robot in advance and controlling the arms and joints so as not to protrude from the operation area. ing.

[0015]

However, in the method of directly controlling the drive of each arm to avoid the collision of each working head, even if the collision of the tip pin of the working head of each arm is completely avoided. The movement of each arm is considerably limited, and it is not easy to completely avoid collision between robots, that is, collision and collision between tip pins of the working head.

Further, when the number of robots increases, the operation of the arm is further remarkably restricted, and there is a limit in efficiently operating all the robots.

On the other hand, the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Sho 59-129691 uses a visual device and detects entry and exit from the interference area by image processing, so that the processing is complicated and takes a long time. Take it. In addition, many facilities such as a visual device are required, and the cost is high.

According to the method disclosed in Japanese Patent Application Laid-Open No. 4-19084, the cost can be reduced because no equipment such as a camera is required. However, since the operation area is determined in advance, the operation is not possible. You will be restricted.

Therefore, it is necessary to solve the problem of completely avoiding collision between moving parts of a robot including at least two arms, for example, work heads, and efficiently operating all robots. Have challenges.

[0020]

In order to solve the above-mentioned problems, the present invention provides an arm for performing a horizontal operation within a predetermined work area while maintaining a constant distance from the work area, and an arm for horizontal movement at the tip of the arm. The robot occupancy quadrant includes at least two robots each having a work head that performs a vertical motion with respect to each robot. Each robot determines a robot occupancy quadrant including an arm and a work head with a current position and an operation position as a center. The collision state of each robot is determined based on the.

The collision state is determined by determining the possibility of collision based on the robot occupancy quadrant before each robot moves, and the case where the robot occupancy quadrants overlap is regarded as the collision state. Even if the robot occupancy quadrants do not overlap, if the other robot occupancy quadrant exists on the straight line connecting the current position and the motion position of one robot, it is considered as a collision state.

In the robot occupied quadrant, the sum of quadrant angles is 3
Allocate to be 60 degrees. Further, preferably, the robot occupancy quadrant is assigned a quadrant angle with the work head as the apex and 360 degrees divided by the number of robots, so that it can be appropriately changed based on the position of the arm.

Preferably, two robots make a pair, and the paired robots are arranged to face each other.

By determining the robot occupation quadrant and determining the collision state of each robot based on the robot occupation quadrant, the collision determination speed is improved.

Moreover, since the possibility of collision is determined based on the robot occupancy quadrant before each robot moves, it is not necessary to consider the collision during the operation of the robot, so that the operation speed of the robot is improved, If the occupied quadrants overlap, it is considered as a collision state, and even if the robot occupied quadrants do not overlap, if the other robot occupied quadrant exists on the straight line connecting the current position and the motion position of one robot, it is considered as a collision state. As a result, the collision between the robots can be completely avoided.

In the robot occupied quadrant, the sum of quadrant angles is 3
Since the assignment is made to be 60 degrees, there is no overlap or gap between the robot-occupied quadrants, so that the collision can be accurately determined. Further, the working head is set as the apex, and an angle obtained by dividing 360 degrees by the number of robots is assigned as a quadrant angle so that it can be appropriately changed based on the position of the arm. The robot occupation quadrant can be defined without being affected by the number of robots.

By arranging two robots as a pair and arranging the paired robots so as to face each other, one quadrant angle is basically 1/4 of 360 degrees, so that the robot is occupied. It is possible to easily determine whether the quadrants overlap each other or whether the robot occupying quadrant of the other robot exists on the straight line connecting the current position and the motion position of the one robot.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a multi-robot system according to the present invention will be described in the following order with reference to the drawings. 1. Outline of multi-robot system 2. Collision avoidance algorithm 3. 3. Judgment of collision using robot occupancy quadrant Prevention of replacement and wraparound 5. Deformation of quadrant due to overhang of second joint (second arm) 6. Multi-robot system details

1. Outline of multi-robot system In a multi-joint robot, a pair of arms are arranged on a base so as to be controllable in the horizontal XY axis directions, and the tips of the arms are perpendicular to the horizontal direction of the arms. Is Z
It has a structure in which a working head, which is a tip head that can be controlled in the axial direction, is attached. For details, refer to Japanese Patent Application No. 6-16252 of the same applicant shown in the prior art.

The preferred embodiment of the present invention has four robots having such a structure, that is, basically four robots.
SCARA (Selective Compliance Assembly Robo)
t Ar-m) It is to control robots synchronously and operate them in one work area. By doing this, we are constructing a system aiming at various applications. In particular, it is most important to avoid collisions between the trajectories of multiple robots and their motion ranges. Below, given motion positions (hereinafter referred to as "grant points")
, An algorithm for avoiding collisions by assigning robots to each other so as not to collide, and various conditions thereof will also be described.

As described above, in this embodiment,
As shown in FIG. 1, it is intended for a system using two robots each having a pair of right-handed and left-handed SCARA robots 19A, 19B and 19C, 19D. The working area origin (0, 0) when the working area 29 is represented by x-axis and y-axis is:
It is on the tip side of the left-handed robot 19B.

As shown in FIG. 2, the length of the arm forming each robot is P as shown in FIG.
(280 mm in the embodiment), the length of the second arm 23A is Q (270 mm in the embodiment). The work head 24A, which is a tool provided at the tip of the second arm 23A, is always α degrees (45 in the embodiment) with respect to the coordinate axis of each robot operating in the work area 29.
The first arm 20A and the second arm 23A have a parallel link structure so as to maintain the angle (degree).

Further, the length from the mounting shaft of the working head 24A attached to the tip of the second arm 23A to the tip is R (80 mm in the embodiment).

As shown in FIG. 3, the work head 24A has a structure similar to that of the prior art, and has a drive portion 22A attached to the rotary shaft 21A provided at the tip of the second arm 23A, and a drive portion 22A. Tip pin 33A provided on the tip of
And a light unit 34A for monitoring the state of the tip pin 33A.

The drive section 22A is attached with an inclination of about 15 degrees with respect to the rotary shaft 21A. Therefore, the tip pin 33A attached to the tip of the drive section 22A.
Is naturally inclined, and has a structure capable of repeating the z-axis movement just like the needle of the sewing machine, that is, the vertical movement.

In order to inspect the printed circuit board, at least four working heads having the above-described structure, that is, probe heads, are required, and each of them can move freely. If, as shown in FIG. 4, the four probe heads indicate the same point (point D in FIG. 2), the situation is the worst and the collision occurs. However, as shown in FIG. 3, the tip pin is inclined and the clearance W
Therefore, the tip pins do not collide with each other when the probe head is located above. Therefore, in this state, the robot is divided into four quadrants with the designated point as the origin, and if each robot is within its quadrant, it is determined that these four robots do not interfere with each other. A method of determining the collision prevention by dividing each quadrant will be described in detail later.

Although the inspection of the printed circuit board has been described here, the invention is not limited to this. For example, by devising a working head, mounting of a minute component on the printed circuit board, assembly of an electronic device, and packaging of a minute box. Of course, it can be applied to the above.

Next, each robot 19 having the above configuration
The operation in A, 19B, 19C and 19D will be described. The operation of each of the robots 19A, 19B, 19C and 19D is a linear motion, and acceleration / deceleration is performed by using a so-called cam curve as a motion curve. Here, it is well known that the cam curve is used as the motion curve. For example, as shown in FIG. 5, when the first robot and the second robot exist, points 1a and 2a are respectively provided.
When you are instructed to move from point 1b to point 2b, the original two points (points 1a and 2a) are started at the same time, and points 1b and 2b
Arrive at the point at the same time. This means that the motion curve at this time is controlled so as to draw a cam curve. Specifically, the first robot is gradually accelerated from the original point 1a to time t, and further after the time t has elapsed. Acceleration is added, and the purpose is 1
When it reaches the point b, it slows down and arrives. In contrast, the second
The robot moves from the original point 2a to the target point 2b at approximately the same speed.

2. Collision Avoidance Algorithm For the quadrants given to each of the four robots described above, first, the four movement positions (grant points) given to each robot are assigned to four robots in 24 ways (4 points). For all combinations of factorials, the quadrant overlap determinations made by each robot, the trajectory collision determination due to the interchange and the wraparound, and the collision determination due to the second joint extension of the robot are performed.

Further, among the combinations which have cleared all the judgments, the combination having the smallest maximum movement locus of the four robots is actually assigned to each robot as a point to be operated. The above-mentioned items will be described in detail later.

When the number of points is not four, that is, when the number of robots instructed to four robots is not four, points are assigned as follows. For example, as shown in Table 1 below, there are 24 combinations of allocations when three points are given. From these combinations, a combination that does not collide with the robot and can be moved in the shortest distance is sought to assign a given point. As a result, the robot to which the scoring point is not assigned does not operate at the current position.

[0042]

[Table 1]

3. Collision determination using the robot occupancy quadrant If a robot is considered with a skeleton model and each element is replaced with a vector, it can be considered that a collision occurs when the vectors overlap, but considering the size of the parts. There will be no. Here, the skeleton model is a model in which the arm is represented by a vector, but since the robot actually has a volume, it is an approximate description. Therefore, it can be said that the vehicle is obviously in a collision state if at least a collision is represented by the skeleton model.

Since the robot used this time is provided with links for tool attitude control and second arm operation, if all of them are made into vectors or surrounded by vectors, it will take a very long time only for collision judgment. Will be spent. Therefore, the work head is used as the apex, and the region where the robot exists is surrounded by two straight lines (quadrants) facing each other at 90 degrees.
Then all the parts of the robot will be in this quadrant. That is, this quadrant is the robot occupied quadrant.

In this state, there is a great possibility of collision when the robot occupied quadrants overlap. For this reason, in order to avoid a collision, it is necessary to assign a given point so that the robot occupation quadrants do not overlap. This idea is not easily affected by the presence or absence of a link forming an arm and the deformation of the work head, and the speed of collision determination of the robot is dramatically improved.

When the robot occupancy quadrants of the four robots are added, it becomes 360 degrees. This is to prevent overlapping and gaps between the robot occupied quadrants, so that the total quadrant angle is 360 degrees even when the number of robots increases. Further, even if the work head or the link shape of the arm is forced to deform the quadrant, if the total quadrant angle is 360 degrees, it can be handled as a robot occupied quadrant. The specific robot occupation quadrant applied to the multi-robot system will be described later.

4. Prevention of replacement and wraparound With the above-mentioned quadrant judgment alone, even if the positional relationship of the given points is the same, as shown in FIGS. 6 (A) and 6 (B), there are several different combinations of allocated robots. Become. However, in the example of FIG. 7, when the robot moves from the state shown in FIG. 7A to the state shown in FIG. 7B (and vice versa), even if there is no overlap in the robot occupancy quadrant when stationary, There is a possibility of causing a collision. This is because, as shown in FIG. 8, one robot (quadrant 3 in FIG. 8) crosses the other robot occupied quadrant (quadrant 1 in FIG. 8). Therefore, the current state and the assigned state are compared, and one robot (quadrant 3) moves around the other robot (quadrant 1) 180 times.
Prevent a collision except when it has rotated more than once as it is considered to be a possibility of a collision. Such a phenomenon can occur only for a robot located on a diagonal line.

5. Deformation of Quadrant by Overhanging Second Joint (Second Arm) In the case of the SCARA robot as used in the present embodiment, as shown in FIG. 9, the second joint is the quadrant occupied by the robot (A in FIG. 9). It may run out of the way. Therefore, whether or not the second joint is projected is determined by the angle of the second arm (β in FIG. 9).
The angle of the arm may be set as a quadrant (A 'in FIG. 9). Here, as described above, since the four robot occupied quadrants are added up to 360 degrees, if the robot in front comes in front of the second joint, the robot occupied quadrant also needs to be changed. Must be careful. On the other hand, if it is behind the second joint, the normal robot occupation quadrant is used.

6. Details of Multi-Robot System The present multi-robot system 1 that employs a collision avoidance algorithm is a system that avoids collisions when performing work with at least two or more arms, and in the embodiment, a multi-joint robot including a pair of arms. Will be described with reference to those facing each other and facing each other.

This articulated robot has the same basic configuration and movement as the conventional robot shown in FIG. 16, and as shown in FIG. 10, it comprises an input unit 2, a control unit 3, and a mechanism unit 4. It is configured.

The input section 2 is for instructing the control section 3 about the operating position of the robot, etc., and is configured to be input from a keyboard or the like.

As shown in FIG. 11, the control unit 3 controls the operation of the arm of the robot. The control unit 3 assigns a robot operation position (grant point) to each robot according to an instruction from the input unit 2. Is defined, a reading unit 6 that is a reading unit that reads information about the robot arm, and a range in which each robot may exist (robot occupied quadrants 7, 8, 9, 10) are defined. A robot occupation quadrant definition unit 11 that is a quadrant definition unit, a collision determination unit 13 that is a collision determination unit that determines the possibility of a robot collision, and a movement distance calculation unit that is a movement distance calculation unit that calculates the movement distance of each robot. Unit 15, combination determination means for finally determining allocation of points, and combination determination and storage portion that is storage means for storing the determined allocation. 6, and a I / O interface 18 for inputting and outputting data and signals between the control unit 3 and the mechanism 4, a servo controller 25A for driving the four robots, 25B, 25C, and 25D.

The point assigning section 5 assigns the plurality of points given from the input section 3 to the four robots 19A, 19B, 19C,
It is an attempt to assign a scoring point in all combinations in how to assign to 19D.

The reading unit 6 includes the robots 19A and 19A.
The angles of the second arms 23 of B, 19C, and 19D are read, and the read data is provided to the robot occupation quadrant definition unit 11.

The robot occupancy quadrant definition unit 11 has the robots 19 and 1 centered on the points assigned by the point assignment unit 5.
9A, 19C, 19D robot occupied quadrants 7, 8, 9,
10 is defined.

The collision determination unit 13 includes four robot occupation quadrants 7 defined by the robot occupation quadrant definition unit 11,
The possibility of collision of the robot is judged based on 8, 9, and 10.

The moving distance calculation unit 15 determines the robots 19
A, 19B, 19C, 19D work heads 24A, 2
The movement distances of the work heads 24A, 24B, 24C, and 24D when 4B, 24C, and 24D move from the current position to the given point are calculated.

The combination determining / storing unit 16 determines a final combination of allocating points, based on the calculation result of the moving distance calculating unit 15, and stores the combination.

The I / O interface 18 is the controller 3
Is an interface for inputting information about the robot arm from the mechanical unit 4 and for outputting an instruction to the mechanical unit 4. For example, an I / O interface board having a plurality of I / O ports Etc.

Servo controllers 25A, 25B, 25
C and 25D are the robots 19A, 19B, 19C and 1
It drives 9D.

The mechanism section 4 is similar to a robot having a pair of right-handed robot 19A and left-handed robot 19B,
The robot includes a right-handed robot 19C and a left-handed robot 19D as a pair. For the structure of the robot, see the related art and Japanese Patent Application No. 6-16252.

A case where the multi-robot system 1 having such a configuration operates while avoiding collisions with each other will be described in detail below with reference to the drawings.

First, the robots 19A, 19B, 19
C and 19D maintain the initial state as shown in FIG. 12, respectively. Here, from the input unit 2, the robots 19A, 19B,
When a maximum of four movement positions (giving points) to which the 19C and 19D should move next are designated, the giving point allocating unit 5 of the control unit 3 changes the given four giving points to four. The robots 19A, 19B, 19C, and 19D are assigned to the robots (steps ST1 and ST2).

Finally, it is not immediately decided how to allocate the points to the robots, and there are many combinations of allocations depending on the number of points and the number of robots. It is necessary to select one. Here, since there are four points and four robots, the allocation method is 4 × 3 × 2 = 24.
[Street] There is. Therefore, allocation of points is attempted for all 24 combinations, one optimal combination is determined from among these, and the robot is driven in that allocation.

The optimum combination here means a combination in which the robots do not collide with each other and the movements of the four robots end the earliest. The collision determination unit 13, the movement distance calculation unit 15, The combination is determined and determined by the storage unit 16.

Even if there are four robots, the point is 4 points.
In some cases, the number of robots is less than the number of robots, and in this case, there are robots to which no points are assigned. However, even in such a case, in principle, all 24 combinations are assigned, and in particular, in the case of 2 points, the combination of 4 points and the combination of 2 in every other If they are arranged in the order of combination, the points can be efficiently allocated as shown in the flowchart of FIG. 13 (steps ST11 and ST12).

Next, as described above, the robot occupancy quadrant definition unit 11 makes two straight lines facing each other at 90 degrees from each vertex as shown in FIG. pull. The area surrounded by these two straight lines formed here is called the robot occupied quadrant. Since the robot occupancy quadrant can be set for each given point, four robot occupancy quadrants 7, 8, 9, 10 can be formed for each combination (step ST2).

Since the central angle (quadrant angle) of each robot occupied quadrant is 90 degrees, the quadrant angle of four robots is 360 degrees. This is to prevent overlapping or gaps between the quadrants, and the total quadrant angle should be 360 degrees even when the number of robots increases or decreases.

However, as shown in FIG.
The joint 26 may overhang. Even in such a case, the collision can be avoided by reading the angle by the reading unit 6 and redefining the robot occupation quadrant (steps ST3 and ST9).

After defining the robot occupied quadrants 7, 8, 9, and 10, the collision determination unit 13 determines whether or not the robot occupied quadrants overlap each other.

The points given are the work heads 24A, 24B, 24C, 2 provided at the tip of the second arm of the allocated robot.
Because of the 4D position, all parts of the robot other than the bases 28A and 28B can be considered to be within the robot occupancy quadrant of the robot. Therefore, it is possible to determine that there is a high risk of collision if the robot occupied quadrants overlap, while there is no possibility of collision if the robot occupied quadrants do not overlap.

The collision means both the collision of the robots at the moving destination and the collision of the robots during the movement. Therefore, in the multi-robot system 1 according to the present invention, means for avoiding a collision is provided for each of these two types of collisions.

In order to prevent the robots from colliding with each other at the moving destination, the control unit 3 is provided with a collision determination unit 13. The quadrant duplication determination unit 13 defines the robot occupation quadrants 7, 8, 9, 1 defined by the robot occupation quadrant definition unit 11.
Regarding 0, it is determined whether or not arbitrary robot occupied quadrants among the four robot occupied quadrants are overlapped, and when they are overlapped, it is determined that there is a high possibility of collision, and an inappropriate score is given. Allocation.

The determination as to whether or not the quadrants overlap is as follows.
Specifically, for example, the following method is used.

As shown in FIG. 12, the work area 2 of the robot is shown.
9 is limited within a certain range by the coordinates having the tip of the second arm 23 of the robot 19B as the origin, and the given point can also be expressed by the coordinates. Therefore, whether or not the robot-occupied quadrants overlap can be determined based on the coordinates of the given point.

The robot occupancy quadrants 7, 8, 9, and 10 are numbered from 1 to 4, and are designated as a first robot occupancy quadrant, a second robot occupancy quadrant, a third robot occupancy quadrant, and a fourth robot occupancy quadrant, respectively. The coordinates of the vertices of the first robot occupied quadrant are (x1, y1), the coordinates of the vertices of the second robot occupied quadrant are (x2, y2), the coordinates of the vertices of the third robot occupied quadrant are (x3, y3), The coordinates of the vertices of the fourth robot occupied quadrant are (x4, y4).

First, it is determined whether or not two adjacent robot quadrants overlap each other. Considering the first robot occupancy quadrant and the second robot occupancy quadrant, as can be seen from FIG. 14A, the first robot occupancy quadrant and the second robot occupancy quadrant overlap when (x1 <x2). Therefore, x1 and x2 are compared, and (x1 <x
In the case of 2), it is determined that the quadrants overlap, and (x1 <x2)
If not, it is judged that there is no possibility of collision.

Similarly, the second robot occupied quadrant and the third robot occupied quadrant
As shown in FIG. 14 (B), the robot occupied quadrants overlap, and in the case of (y2> y3), the third robot occupied quadrant overlaps the fourth robot occupied quadrant as shown in FIG. 14 (C). In the case of (x3> x4), the fourth robot-occupied quadrant and the first robot-occupied quadrant overlap in the case of (y1> y4), as shown in FIG. Determine whether or not.

If adjacent robot occupied quadrants overlap each other according to the above determination, the determination processing is immediately stopped,
It is determined that the assignment of improper points is given, and the next combination is determined (steps ST4, ST10, ST1).
3).

If there is no overlap between two adjacent robot occupancy quadrants, it is next determined whether or not two diagonally occupied robot quadrants overlap.
4).

In the first robot occupied quadrant and the third robot occupied quadrant, as shown in FIG. 15A, (x1 <
x3) and (y1> y3), in the second robot occupation quadrant and the fourth robot occupation quadrant, as shown in FIG. 15B, when (x2> x4) and (y2> y4), respectively. The quadrants overlap. If the quadrants overlap,
Immediately, the determination process is stopped, and it is determined that improper scoring has been performed, and the determination of the next combination is made (step ST1).
0).

With a combination that clears all of the above judgments, it is possible to avoid collision between robots at the moving destination.

On the other hand, in the collision determination unit 13, the work heads 24A, 24B, 24C provided at the tips of the second arms 23A, 23B, 23C, 23D of the robot in order to avoid collision during movement. , 24D moves from the current position to the given point, the work head 2
It is determined whether 4A, 24B, 24C, and 24D may pass through another robot occupied quadrant, that is, whether the trajectory of the robot passes through another robot occupied quadrant. This determination is made only for the combinations that have cleared the above-mentioned quadrant duplication determination (step ST
5).

If the result of determination is that the robot may pass through the robot occupancy quadrant, it is determined that there is a high possibility of a trajectory collision, and it is treated as improper point allocation (step ST
10).

The determination of whether or not the locus of the robot passes through the quadrant occupied by another robot is specifically performed by, for example, the following method.

Since the motion of the robot adopted in the multi-robot system 1 according to the present invention is only linear motion,
The work heads 24A, 24B, 24C and 24D pass within the quadrants of the other robots because the locus of one robot is the work heads 24A, 24B and 24 of the other robot.
Only when the angle of turning around C and 24D (swap / wrap-around angle 30) is 180 degrees or more. Therefore, when the interchange / wrap-around angle exceeds 180 degrees, it can be determined that there is a possibility of collision. In addition, such a phenomenon is
Since it can occur only when one robot and the other robot are located on the diagonal line, the determination is performed only in that case.

Specifically, the absolute values of the inclinations of the straight line 31 connecting the current position of the robot and the vertex of the robot occupied quadrant on the diagonal line and the straight line 32 connecting the vertex of the robot occupied quadrant and the robot's given point. Is calculated from the coordinates and compared to find that the interchange / wraparound angle 30 is 18
It can be determined whether it is 0 degrees or more.

For example, as shown in FIG. 8, a robot 19C
, Goes around the first robot occupied quadrant,
The coordinates of the vertices of the first robot occupied quadrant are (x1, y1),
If the coordinates of the current position of the robot 19C are (x3, y3) and the coordinates of the given point of the robot 19C are (x3 ', y3'), a straight line 31 connecting the current position of the robot 19C and the apex of the first robot occupied quadrant The slope is (y1-y3) / (x1
-X3), the inclination of the straight line 32 connecting the apex of the first robot occupied quadrant and the given point of the robot 3 is (y3'-y1) / (x
3'-x1). Therefore, the inclinations of these two straight lines are compared, and if the absolute value of the inclination of the straight line 31 is larger, it can be determined that the trajectory of the robot 21 is 180 degrees or more around the first robot occupied quadrant.

Here, the absolute values of the inclinations are compared with each other because the inclinations sometimes have a negative value. When the slope of the straight line 31 has a positive value and the slope of the straight line 32 has a negative value, or conversely, the slope of the straight line 31 has a negative value and the straight line 3 has a negative value.
There is no need to consider the case where the slope of 2 has a positive value. In these cases, either the robot occupied quadrants on the diagonal line (the first robot occupied quadrant and the third robot occupied quadrant in FIG. 16) must be overlapped with each other, or the trajectory and the robot occupied quadrant do not collide. Because it is. Therefore, it suffices to consider only when the signs of the inclinations of both straight lines are the same.

Further, in the case shown in FIG. 8, the robot 1
Even when the positional relationship between the current position of 9C and the given point is reversed, that is, the direction of the trajectory is reversed, x3 and x
Since only 3 ', y3 and y3' are reversed, the determination can be made by the same method.

Similarly, for the other three robots,
Similarly, the possibility of collision between the locus and the robot-occupied quadrant can be determined based on the magnitude of the inclination of the two straight lines.

As described above, by assigning points according to the determination of trajectory collision, it is possible to avoid collision between robots during movement.

Next, with respect to the combination that clears both the quadrant overlap determination and the trajectory collision determination described above, the movement distance calculation unit 15 provided in the control unit 3 causes the four robots to move from the current positions to the given points. Then, the moving distance is calculated (step ST6).

As described above, the motion of this robot is only a linear motion. Therefore, for example, the moving distance when the robot 1 moves from the current position (x1, y1) to the given point (x1 ′, y1 ′) is obtained by the following mathematical expression (1).

[0095]

[Equation 1]

By the above method, the moving distance of each robot is obtained for all the combinations that have cleared the quadrant overlap determination and the trajectory collision determination (step ST7), and the optimal allocation is determined by the combination determination and storage unit 16. In making this determination, a combination is selected in which the movement of all four robots ends the earliest.

Since each robot performs acceleration / deceleration by using the cam curve as shown in FIG. 5 as a motion curve as described above, it can be said that all the robots finish moving earlier in a combination having a shorter maximum movement distance. Therefore, if a combination having the smallest maximum movement distance of the four robots is selected from the combinations that have cleared the quadrant overlap determination and the trajectory collision determination, the combination has the shortest movement time.

For example, there are two combinations, combination 1 and combination 2, in which all the judgments are cleared, and the movement distance of each robot of combination 1 is (3, 4, 2,
3), the movement distance of each robot of combination 2 is (2,
1, 5, 1), the maximum moving distance of combination 1 is 4, and the maximum moving distance of combination 2 is 5
Therefore, the combination 1 having the smaller maximum value is selected.

The combination thus determined is the optimum combination described above. Therefore, if a point is assigned to each robot in the combination determined here and the robots are driven, desired motions can be achieved in the shortest time without collision between the robots (step ST
8).

By storing the combination determined here in the combination determination and storage unit 16, it is possible to easily perform the trajectory collision determination and the calculation of the moving distance at the time of the next assigning of points.

By repeatedly assigning the points according to the method described above, the continuous operation of the robot can be efficiently controlled.

In the above embodiment, the case in which the robot occupancy quadrant having the designated quadrant angle for each of the four robots is defined has been described. However, not only in this case, but the sum of the quadrant angles is 360 degrees. Therefore, it is possible to avoid the collision regardless of the number of robots.

[0103]

As described above, according to the present invention, since the collision state is judged based on the robot occupancy quadrant, the collision can be completely avoided and desired work can be efficiently performed. It has an excellent effect.

Further, since it is not affected by the shapes of the arms and work heads, the number of robots, etc., it has an excellent effect that it can be used for various purposes.

[Brief description of drawings]

FIG. 1 is a schematic plan view of four SCARA robots constituting a multi-robot system according to the present invention.

[FIG. 2] One S constituting the multi-robot system
It is a top view of a CARA robot.

[FIG. 3] One S constituting the multi-robot system
It is a side view of a work head of a CARA robot.

[FIG. 4] Four S's constituting the multi-robot system
FIG. 9 is a schematic plan view in the case where the working head of the CARA robot collides.

FIG. 5: SCAR constituting the multi-robot system
It is explanatory drawing which shows the movement curve of A robot.

FIG. 6 is an explanatory diagram showing an example of how to allocate points in the multi-robot system.

FIG. 7 is an explanatory diagram showing an example of movement of a robot in the same multi-robot system.

FIG. 8: SCARA in the same multi-robot system
The trajectory of the robot is 180 around the other robot occupied quadrant.
It is explanatory drawing which showed an example at the time of exceeding a frequency.

FIG. 9: SCARA in the same multi-robot system
It is explanatory drawing which shows the deformation | transformation of a robot occupied quadrant when the 2nd joint of a robot projects.

FIG. 10 is an explanatory diagram showing an overall configuration of the multi-robot system.

FIG. 11 is an explanatory diagram showing a configuration of a control unit of the multi-robot system.

FIG. 12 is an explanatory diagram showing a common work area of four SCARA robots constituting the multi-robot system and a quadrant occupied by each robot.

FIG. 13 is a flowchart showing an operation of the multi-robot system.

FIG. 14 is an explanatory diagram showing a case where adjacent robot occupied quadrants in the same multi-robot system overlap.

FIG. 15 is an explanatory diagram showing a case where diagonally occupied robot quadrants in the same multi-robot system overlap.

FIG. 16 is a perspective view of an articulated robot according to a conventional technique.

FIG. 17 is a schematic explanatory diagram showing a system configuration of the articulated robot.

[Explanation of symbols] 1 multi-robot system 2 input section 3 control section 4 mechanism section 5 point assigning section 6 reading section 7 first robot occupied quadrant 8 second robot occupied quadrant 9 third robot occupied quadrant 10 fourth robot occupied quadrant 11 Robot Occupied Quadrant Definition Section 13 Collision Determination Section 15 Moving Distance Calculation Section 16 Combination Determination and Storage Section 18 I / O Interface 19A, 19B, 19C, 19D Robot 20A, 20B, 20C, 20D First Arm 21A, 21B, 21C, 21D rotating shaft 22A, 22B, 22C, 22D drive unit 23A, 23B, 23C, 23D second arm 24A, 24B, 24C, 24D working head 25A, 25B, 25C, 25D servo controller 26A, 26B, 26C, 26D second Joint 27 Second arm overhang angle 2 8A, 28B Base 29 Working area 30 Swap / wrap-around angles 31, 32 Straight lines 33A, 33B, 33C, 33D Tip pins 34A, 34B, 34C, 34D Camera and light unit 50 Base 51A, 51B, 51C, 51D Arm 52A , 52B, 52C, 52D Working head 53 Control unit 54A, 54B First rotation motor 55A, 55B, 68 Gear box 56A, 56B, 56C, 56D First arm 57A, 57B, 57C, 57D Second arm 58A, 58B , 58C, 58D Rotating shafts 59A, 59B, 59C, 59D Tip pins 60A, 60B, 73 Timing belts 61A, 61B Second turning motor 62 Fixed arms 63A, 63B, 64A, 64B, 65A, 65B Connecting rods 66, 75 Boss 67 Connection arm 69A, 9B, 70A, 70B lever arm 71 driving the motor 72 pulley 74 mounting block 76 rotating lever 77 and 79 bearing portion 78 rotation transmitting means D collision point W clearance

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toji Nakazawa 3138-3 Tana, Sagamihara City, Kanagawa Prefecture TESCON CORPORATION

Claims (8)

[Claims] 1. An arm for performing a horizontal operation while maintaining a constant distance from the work area within a predetermined work area, and a working head for performing a vertical operation with respect to the horizontal operation of the arm at a tip of the arm. The robot comprises at least two robots, each of the robots determines a robot occupancy quadrant including the arm and the work head centering on a current position and an operation position, and determines a collision state of each robot based on the robot occupancy quadrant. A multi-robot system characterized in that 2. The multi-robot system according to claim 1, wherein the collision state is determined by determining the possibility of collision based on the robot occupancy quadrant before each robot moves. 3. The multi-robot system according to claim 1, wherein the collision state of the robot is judged as a collision state when the occupying quadrants of the robots overlap each other. 4. The collision state of the robots is determined when the robot occupancy quadrants do not overlap, and when the other robot occupancy quadrants exist on a straight line connecting the current position and the motion position of one robot. The multi-robot system according to claim 1, 2 or 3, characterized in that 5. The multi-robot system according to claim 1, wherein the occupying quadrant of the robot is assigned such that the sum of quadrant angles is 360 degrees. 6. The multi-robot system according to claim 5, wherein the robot occupying quadrant has a work head as an apex and an angle obtained by dividing 360 degrees by the number of robots is assigned as a quadrant angle. . 7. The multi-robot system according to claim 5, wherein the allocation of the quadrant angle can be appropriately changed based on the position of the arm. 8. The multi-robot system according to claim 1, wherein the two robots make a pair, and the paired robots are arranged to face each other.