JPH0757454B2 - Parts group movement management method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parts group movement management method for an industrial robot, and particularly facilitates creation of a work instruction program when assembling a plurality of parts such as mechanical parts and electronic parts. The present invention relates to a component group movement management method suitable for realizing the above.

[Background of the Invention]

Recently, industrial robots have been rapidly spread with the progress of microelectronics technology, and software design for giving work instructions such as assembly to the robot is also increasing.

There is a specification of the robot programming language AL, which was established for the software design by the Artificial Intelligence Laboratory of Stanford University in the United States. For details, see "AL USERS'M" by Shahid Mujtaba and others.
ANUAL '', Stanford Artificial Intelligence Laborator
y Memo AIM-323, January 1979.

However, this specification is ALGOL language-like, and moreover, '→',
In order to describe using many symbols such as' ↑ 'and'≡', when using the program, for example, when a general keyboard is used as the input means, the above symbols are special There was a problem in use because handling was necessary. Further, when expressing an assembly work by a robot, generally, there are many structural descriptions such as compound and parallel. Therefore, in the conventional method of directly expressing the movement of the robot hand in a program based on the reproduction of teaching data, when the assembly work becomes complicated, the assembly work can be performed only by the expression in the program instructing the work. It was difficult to get a good grasp of the contents and the progress of the assembly. At the same time, it took a lot of time to find typographical errors. Therefore, from the character for description →, ↑, ≡
It is possible to use a general keyboard sufficiently by eliminating the symbols such as, and from the practical point of view, it has excellent expandability of work expressions and quick response to syntactic changes. It was expected that the specifications of the robot programming language, which was modified in the wind, would be realized at an early stage.

[Object of the Invention]

An object of the present invention is to solve such a conventional problem, and to create an assembly work program for a robot that combines a plurality of parts to form a new complex, thereby reducing the inconvenience at the time of input by a simple and inexpensive method. It is an object of the present invention to provide a parts group movement management method that can be easily eliminated to understand the work content.

[Outline of Invention]

In order to achieve the above object, a parts group movement management method of the present invention includes a connection relationship management table that stores each target part to be assembled by a robot, a parent of the part, a child of the part, and a sparse / dense state between the parent and the child. When a moving part is designated, a tree structure pointer / stack table that changes with the above process is created, first the position and orientation of the moving part of the part is calculated, and then the tree structure pointer Write the part to the stack table as a parent, then search all the child parts having the article part as a direct parent from the connection relation management table, and write the child part to the tree structure pointer / stack table. The position and orientation of only the component indicated by the latest pointer is calculated, and the above process is repeated as long as there are child components.

Example of Invention

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

The parts group movement management method of the present invention is a robot program whose expression is modified in PASCAL language style so that input can be performed using a general keyboard as described above, and the work content and progress of assembly can be easily grasped. Although details will be described later in the language specifications, appropriate data indicating an assembly part or attribute is given a name, and the connection relationship between each and the assembling work are described using the name. This makes it possible to create a robot assembly work program that indirectly determines the movement.

For that purpose, it is necessary to manage what kind of connection the specified part has with other parts and the robot hand, and regarding the'tree structure 'for doing so, FIG. 2 (a)-(d) ), FIG.

First, FIGS. 2 (a) to 2 (d) are views showing a work process of assembling components and a connection relation between components in each process in a “tree structure”. In the figure, RH is a robot hand for assembling parts, 1,3,16,18 are parts for assembly, and 26,27 are working tables.

In the case of the assembling work illustrated in each of (a) to (d) of FIG. 2, first, the robot hand RH is made to grasp the part 1 as shown in FIG. 26 Move to the part 3 above, and fit the convex part into the groove of the part 3 to be integrated. In the tree structure at this time, while the robot hand RH is grasping the component 1, the component 1 and the robot hand RH are connected as shown in FIG.

Then, the integrated one is grasped by the robot hand RH, and is moved from the table 26 to the part 16 of the parts group already integrated on the table 27 as shown in FIG. In the tree structure at this time, as in the above, as shown in (c), the parts 1 and 3 and the RH and the parts 16 and 18 are connected by solid lines.

Then, move the moved integrated parts 1 and 3 to the part 1 as shown in (d).
6) Place the parts on top of the parts 18 so that they are along the plane perpendicular to the parts 18, combine them, and separate the robot hand RH. The tree structure at this time is the same as the above, as shown in FIG.
Connect the part 16 to the part 18. In the expression of the tree structure, the upper part connected by one tree (solid line) has a “parent” relationship and the lower part has a “child” relationship, and the unconnected parts show an isolated state.

Similarly, although the work process of assembling the parts is not shown, the parts 1
An example of the connection relations of ~ 25 can be represented as shown in Fig. 3 by expressing it as a "tree structure". When expressing the connection between two parts made of one tree in a language, the following rules are applied.

As a rule, there is a parent-child dependency relationship between two parts, but there must always be one'parent 'from'child'.

Rules and parent-child relationships have a state of'sparse 'and'dense'.
That is, "sparse" means that when the "parent" is instructed to move, the "child" also moves to one place, but when the "child" is instructed to move, the "parent" is in a stationary state. (In the figure, the circled tree is a sparse parent-child relationship). On the other hand, "tight" means a state where the parent and child move to one place even if they are instructed to move. Therefore, the parts that are simply stacked are in a “dense” state, and the parts that are tightened with bolts or the like are in a “dense” state.

Also, as will be described later in detail, in the moving work of FIG.
When the work is expressed by the movement of parts in the robot language and the robot hand RH is actually moved, it is necessary to indirectly determine the position / orientation of the robot hand RH in the reference coordinate system according to the movement of the parts. There is. For this reason, the contents of the connection relationship between the part that is the object of language expression and the robot hand RH are recognized from the tree structure.

As shown in FIG. 2, by expressing the connection state between the parts and the robot hand RH at each time point by a tree structure, it is possible to know the change in the connection state as the assembly work progresses. By giving the connection relationship by such a tree structure, it is possible to obtain the position / orientation that each part should have in the reference coordinate system. Similarly, the position / orientation of the robot hand RH is By knowing the relative relationship of, it becomes possible to obtain from the position / orientation of the moving target part at the moving destination.

Next, as shown in FIG. 3, each part (1
25), the connection relation management table (hereinafter referred to as RELATB) created to manage the connection relation will be described with reference to FIG.

FIG. 4 is a RELATB expressing the contents of the'tree structure 'illustrated in FIG.

In RELATB, each target part name (1,2,3, ..., 25) to be assembled as shown in Fig. 4 is directly stored in the table address (1,2,3 ,.
, 25), and also'PFRM ',' CHILDA ',' CNE
It consists of CTD 'and'NRGD' items.

In the first item'PFRM ', store the table address of its own'parent', and set it to “0” if there is no'parent '. In the next item'CHILDA ', store the table address of its own'child', and set it to “0” when there is no child.
When there are two or more "children", use the next item, "CNECTD". The next item'CNECTD 'is used as follows. Now, there are 3 "children" for "parents"("Kou","Otsu",
If there is, then the table address where the first child's "Kou" is in the "parent" item "CHILDA", and the second child is "Otsu" in the "Kou" item "CNECTD" The table address where
Similarly, the third child's “Hei” is included in the “CNECTD” of that “Otsu”.
Set each table address where there is, and set “0” in the item “CNECTD” of that “丙” because you are the last “child”.

The fourth item'NRGD 'stores'sparse' (set “1”) or'dense '(set “0”) status between parent and child.

That is, for example, in component 1, component 16 is the “parent”, component 2,
Since there are 3 and 4'children ', the items'PFRM'and'CHILDA'at address 1 (part 1) of RELATB are "16" and "2", respectively.
Items "PFRM" and "CNECTD" at address 2 (part 2) are "1" and "3" respectively, and items "PFRM" and "C" at address 3 (part 3) are respectively
Set "1" and "4" to NECTD 'and set "1", "5" and "1" to items'PFRM', 'CHILDA'and'NRGD'at address 4 (part 4) respectively. To do.

Next, the'tree structure 'shown in FIG. 3, that is, the connection relationship between parts changes every moment as the assembly process progresses. A tree structure pointer / stack table (hereinafter, referred to as TPS) to be described will be described with reference to FIG.

FIG. 5 is a diagram showing the structure of the TPS 33, the movements 34a to 34h of the stack pointer and the processing direction 35.

TPS33 stores the address of RELATB where there is a search target component in the connection relation of'tree structure ',' RELPTR '
And the end of various calculations for that part (set "1"),
Flag'CAL for indicating the status of incomplete (set to “0”)
It consists of C '. The TPS33 shown in the figure is the contents of parts 1 to 10 in FIG.
There are 13 contents. Also, the horizontal direction shows the same table address of TPS33, and the left side of the pair of records is the item'RELPT.
R ', the item on the right is'CALC'.

That is, by changing the stack pointer from the position / orientation of the part 1 at the movement destination, the position / orientation of each of the parts 10 → part 9 → part 8 → part 7 → part 6 is calculated, and the part 5 is the “child” part. 13 to 11 are also included in the calculation, the part 4 is omitted (since it has already been calculated), and the parts 3 to 2 are calculated in this order.

In other words, when a part moves, its new position needs to be calculated, and when a plurality of integrated parts move, it is based on the parent-child relationship and the coordinate transformation matrix between the parent and child that form the tree structure. And calculate the new position of each part. In the calculation, due to the relationship of "sparse" and "dense" between parent and child, a) always move as a unit, the position changes but the coordinate transformation matrix between parent and child does not change.

b) Only the'child 'moves, and the coordinate transformation matrix between the parent and child also changes.

c) The position and coordinate transformation matrix do not change regardless of the moving parts.

And can be classified into three.

In each of the states a), b), and c) described above, in the “tree structure” of FIG. 3, the route when starting from the component 1 and turning in the “parent” direction (component 16 side) is the key route 31. And call it
When the'parent 'and the'child' in the'sparse 'relationship first encountered on this key route 31 are set to FP (part 21) and FC (part 18), respectively, the following states a, b, c Corresponding to.

i) Each'child 'that makes FC a'parent' and can be followed with it (ie it is also indirectly in a'child 'state)
All parts are each part in state a.

ii) FC itself is in state b.

iii) Each component other than i) (state a), ii) (state b) is in state c.

As a result, the parts 1
If there is a description to move the
The calculation for changing is performed for all parts (2 to 18) corresponding to the states a and b of i). This calculation is performed by determining all target parts using the table TPS33 with the part 1 as the starting point. For example, the components 1 to 13 and the components 1 and 14 to 18 are determined. Note that FIG. 5 described above is an example of the calculation process of the components 1 to 13, and the stack pointer indicating the top of the TPS 33 is moved as indicated by arrows 34a to 34h for processing.

Next, referring to FIGS. 1a and 1b, a method for obtaining a predetermined value for each part and robot hand (RH) by using two tables, RELATB and TPS33, based on the'tree structure 'will be described.

When a moving part (which is now called part 1) is specified, first the position / orientation of the part 1 at the moving destination is calculated, and then "-1" is set in RELAPB of the flag register provided inside.
Is set, and the component 1 is written in the TPS33 as a'parent '(steps 101 to 103). In addition, the item at address 1 of TPS33'RELPT
The table address "1" of RELATB part 1 and the calculated "1" are set in R'and item'CALC ', respectively.

Next, search for all'child 'parts that have a direct parent as part 1 based on the RELATB items'CHILDA'and'CNECTD'. If there are multiple'child' parts, search for them. Register to the item'RELPTR 'of TPS33 in order, calculate the position and orientation of only the part pointed by the latest pointer of TPS33, and add the item'CAL
Set “1” to C ′ (steps 104 to 107). This process is continued as long as there are'child 'parts, and is registered as shown in FIG. For components that have not been calculated or need not be calculated, enter "0" in the item'CALC '.

On the other hand, when the number of its'child 'parts is 1, the stack pointer value of TPS33 is decremented by -1, and when the value is 1, the processing of the'parent' side is performed this time, so the item'RELPTR there. The contents of 'is set in the flag register RELAPB, and the part of the RELATB item'PFRM' with the contents (part name) of'RELPTR 'is set as the new'parent' in the flag register RELAPN provided inside (step 108 ~ 11
1). When the value obtained by subtracting -1 is not the first address, the process returns to step 104.

Next, check the parent-child relationship between the old'parent 'of the flag register RELAPB and the new'parent' of the flag register RELAPN, and check the'dense '.
In the case of the relation of, the position / orientation of the new'parent 'is calculated from the position / orientation of the old'parent' and the relative conversion matrix between the old and new parents, and after updating the data, the item'CALC 'at the 1st address of TPS33. Set “1” to and return to step 104 (steps 113, 115, 11
6). On the other hand, when the relationship is'sparse ', the relative conversion matrix between the old and new parents is calculated, the data is updated, and the processing is ended.

This processing is executed until the content of the flag register RELAPN is "0", that is, there is no'parent '(steps 22 and 23) (step 112).

In step 107, when the TPS 33 as shown in FIG. 5 is created, the stack pointer described above is changed to calculate the position of each component in the x, y, and z axis directions and the posture of the component such as inclination. .

FIG. 6 is a block diagram of an apparatus based on this system.

In order to process the creation of RELATB described above and the selection of target parts for which position / orientation calculation is required using both RELATB and TPS33 tables, a parts group movement management device 36 and a general-purpose processing device
39 to execute the following processing operation.

The RELATB creation processing unit 37 of the component group movement management device 36, which has received the data (connection relation expression) describing the connection relation of the components from the processing device 39, creates the table RELATB as shown in FIG. 4 based on the input data. create. When the created RELATB is input, the target component selection processing unit 38 causes the processing device to operate similarly to the above.
Using the created RELATB and table TPS33 based on the (movement expression) data describing the movement of the component from 39 and the component selection instruction from the calculation processing unit 41, calculation is performed in connection with the instructed component. Select the target part,
It is sent to the processing device 39.

In this way, it is possible to describe the robot assembly work by using the connection relationship with the robot hand RH for the name of the given part, to determine the indirect movement of the robot hand RH, and to directly move the movement of the robot hand RH. Compared with the case of expressing, it is easier to understand the work contents from the program,
It is possible to create a program that is hard to make mistakes.

In addition to expanding the names given to the parts, in addition to the names given to the positions that represent the parts, give names to positions that are convenient for the work expression, such as grooves and holes in the same parts and the gripping points of the robot hand RH. , By giving them mutual connection
It is also possible to describe the program more easily.

〔The invention's effect〕

As described above, according to the present invention, a table is created for connection relationships between parts to be assembled, and a part having a relationship with a moving part is selected from the table to determine the position / position at the moving destination.
Since the posture is calculated, it is possible to create a robot assembly work program that combines a plurality of parts to form a new complex without preparing special software, and it is easy to grasp the work contents. Further, since no special symbol is used as the descriptive character, the input work becomes easy.

[Brief description of drawings]

FIGS. 1a and 1b are process flowcharts of parts group movement management showing an embodiment of the present invention, FIGS. 2 (a) to 2 (d) are views for explaining an assembling process and its tree structure, FIG. 3 is a tree structure representation diagram, FIG. 4 is a configuration diagram of a connection relation management table (RELATB), FIG. 5 is a diagram for explaining a tree structure pointer / stack table (TPS) and its processing operation, and FIG. FIG. 1 is a device configuration diagram showing an embodiment of the present invention. 1 to 25: Parts, 26, 27: Table, 31: Key route, 32: Sparse parent-child relationship, 33: TPS, 34a to 34h: Stack pointer operation direction, 35: Processing direction, 36: Parts group movement management Device, 37: R
ELATB creation processing unit, 38: target component selection processing unit, 39: processing device, 40: determination unit, 41: calculation processing unit, RH: robot hand.

Claims (1)

[Claims] 1. A connection relation management table that stores each target part to be assembled by a robot, a parent of the part, a child of the part, and a sparse / dense state between the parent and child, and a tree structure pointer that changes with the process of assembly.・
When a stack table is created and a part to be moved is specified, first the position and orientation of the part at the moving destination are calculated, and then the part is written in the tree structure pointer / stack table as a parent, and then All child parts having the article part as a direct parent are searched from the connection relation management table, the child parts are written in the tree structure pointer / stack table, and the position and orientation of only the element indicated by the latest pointer is calculated. Then, hereinafter, a component group movement management method characterized in that the above processing is repeated as long as there are child components.