JPH05282405A - System for supporting assembling work plant by computer - Google Patents

Abstract

PURPOSE:To configure the system for supporting an assembling work plan by a computer by configuring a data base in which constraint on the middle way of assembling and constraint representing a final assembling state are attached on a component which comprises an assembly. CONSTITUTION:On the middle way of assembling, cylindrical constraint C1 is attached on the components 1, 2, and cylindrical constraint C2 on the components 1, 3, and torsion constraint H3 on the components 3, 2, however, plane constraint E4, E5 are added on them in final assembling. In such a case, the constraint which supplies the final assembling state is omitted from the one in the final assembling state one by one, in other words, the plane constraint E4, E5 are omitted sequentially. Firstly. the component 3 can be moved by omitting the constraint E4, which expresses that the component 3 can be assembled after the components 1, 2 are assembled. Secondly, the component 1 can be moved by omitting the constraint E5, which expresses that the component 1 is assembled in the component 2 and the component 3 is assembled finally. Thereby, it is possible to automatically decide the assembling sequence of the component and the motion of the component to be taken when it is assmebled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for programming operation for assembling by various automatic machines such as robots, and for assembling work plan for generating instructions of an assembling procedure to an operator using a computer. Assembly work plan computer support system.

[0002]

2. Description of the Related Art Conventionally, for example, the 1991 Autumn Meeting of the Japan Society for Precision Engineering Autumn Conference PP.563-564 Iizumi, Kanai, Takahashi, "Determination of assembly state based on component model information"
As shown in, the method of displaying the constraint between the parts at the time of assembly by a mathematical formula has been announced.

[0003]

The above-mentioned prior art describes a method of determining the final assembly state based on the constraint condition between parts. In this method, the assembly procedure and the parts to be assembled should be taken. It was difficult to generate motions, and it was not possible to perform an assembly work plan or assembly process design with a computer.

The object of the present invention is to decompose the restraint conditions between parts into two types, that is, during assembly and at the end of assembly, and analyze the possible motions of the parts under restraint. An object is to provide an assembly work plan computer support system capable of generating.

[0005]

The above object distinguishes the constraint condition between parts during the assembly operation from the constraint condition at the end of assembly, and determines the assembly order of the parts from this constraint condition. Furthermore, from the constraint conditions during assembly operation, the possible motions of the parts under each constraint are expressed in a linear space, and the possible motions of the parts during the assembly operation are obtained from the set operation of the linear space. Support assembly work planning.

[0006]

According to the present invention, by adding constraint condition data to the parts constituting the assembly, the assembly procedure and the operation of the parts at the time of assembly can be determined, and the optimum assembly procedure and the work instruction for the assembly can be specified. It is possible to realize automatic generation by a computer or a support system for designers.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a simple assembly according to the present invention.
Shows the case where it consists of three parts, for example CA
It is displayed as D data. In this assembly, the shaft of the component 1 is inserted into the hole of the component 2 and fixed with the screw 3.
During the assembling operation of this assembly, the constraint between the parts 1 and 2 is a cylindrical constraint C, the constraint between the component 1 and the screw 3 is a cylindrical constraint C, and the constraint between the components 2 and 3 is a screw constraint H. Therefore, the constraint between the parts is expressed as shown in FIG.

Since the constraint between the components 1 and 2 is a cylindrical constraint C, the axis of the component 1 is defined as a Cartesian coordinate whose axis is the Z axis.

Similarly, orthogonal coordinates are determined in the hole of the component 2 such that the axis of the hole is the Z axis. And these Cartesian coordinates are C
_Set to ₁ . Here, C is a cylindrical constraint, and the suffix 1 indicates that the same numbers are combined.

Although the coordinates are defined as the constraints as described above, for constraints other than the cylindrical constraint, for example, advance constraint P, rotation constraint R, screw constraint H, plane constraint E, spherical constraint S, etc. are determined.
Furthermore, for each constraint, the possible motion of the part under the constraint is defined as follows.

Rotational constraint R: Rotation around the Z axis Advance constraint P: Translation along the Z axis Screw constraint H: Helical motion around the Z axis Cylindrical constraint C: Rotation around the Z axis and translation along the Z axis Plane constraint E: Rotation around Z axis and translation along X and Y axes Sphere constraint S: Rotation around X, Y and Z axes Generally, a complicated constraint rotates and can be expressed as a combination of a corner and a screw constraint. .. For example, the plane constraint E is expressed by the following equation (1).

[0013]

[Equation 1]

The following equation (2) expresses rotation around the Z axis.

[0015]

[Equation 2]

Further, the following equation (3) represents the translation along the X and Y axes, respectively.

[0017]

[Equation 3]

U represents the set sum of motions.

In this way, the required constraints can be defined.

By defining the types of restraint (cylindrical restraint C, advance restraint P, rotation restraint R, screw restraint H, plane restraint E, sphere restraint S) and their coordinate positions for each component constituting the assembly, Represents the relative relationship between.

The positional relationship of the parts during the assembling operation is determined from the constraint conditions defined as follows. First of all, the deviation between the two coordinates is defined for that purpose.

The coordinates of two constraints with the same number,
Therefore, the coordinate of the axis of the component 1 and the coordinate of the two holes of the component, which are constraints of C, are expressed by the following equations (4) and (5), respectively.

[0023]

[Equation 4]

[0024]

[Equation 5]

Where p is the position of the origin of the coordinates, l, m, n
Is the direction coarc vector of the X, Y, and Z axes, and the subscript indicates the part number.

Here, r and s are calculated from the following relational expressions of (Equation 6), (Equation 7), (Equation 8), (Equation 9) and (Equation 10).

[0027]

[Equation 6]

[0028]

[Equation 7]

[0029]

[Equation 8]

[0030]

[Equation 9]

[0031]

[Equation 10]

The following equation (11) represents the deviation between the two coordinates as a 6-dimensional vector.

[0033]

[Equation 11]

In order to obtain the positional relationship between the parts during assembly,
First, the position of each part is assumed to be appropriate. At this time, a deviation occurs between the coordinates of the corresponding constraints. Therefore, it is assumed that a force corresponding to the deviation acts on the component as shown in FIG. At this time, the deviation of the restraint movement direction is ignored.

That is, the following equation (Equation 12) represents the force torque F corresponding to the deviation between the two coordinates as a six-dimensional vector consisting of the force f and the torque m.

[0036]

[Equation 12]

However, depending on the type of constraint, the following (Equation 13)
Expression, (Expression 14) Expression, (Expression 15) Expression, (Expression 16) Expression, (Expression 17) Expression, and (Expression 18) Expression.

[0038]

[Equation 13]

[0039]

[Equation 14]

[0040]

[Equation 15]

[0041]

[Equation 16]

[0042]

[Equation 17]

[0043]

[Equation 18]

Although the screw constraint H is special, it can be handled in the same manner as the cylindrical constraint C. Since one part has multiple constraints,
The force torque applied to the parts is the sum of the force torques due to each constraint. The assembly is fixed with one of the parts as a reference. It is assumed that the other parts move due to the force torque received by the deviation, and the motion analysis of each part is performed to find the positional relationship where the force received by each part becomes zero. This position relationship is the position that each part should assume during assembly.

When this operation is performed on the parts shown in FIG.
The positional relationship data of is determined. These are input to the computer based on the CAD data shown in FIG. 1 or 3.

Next, the computer obtains the possible motion of each part under the constraint from the input positional relationship data.
In FIG. 4, it is assumed that the component 2 is a component whose position is fixed, fixed coordinates are defined for this, and the coordinates of each constraint are expressed with respect to this fixed coordinate. The possible movements of the parts due to the restraint are as follows. Assuming that the coordinate origin of the constraint is the direction cosine of the p, X, Y, and Z axes, the possible motion of each component is represented by the linear space spanned by the six-dimensional vectors shown for each constraint.

The rotation constraint R is given by the following equation (19).

[0048]

[Formula 19]

The advance constraint P is given by the following equation (20).

[0050]

[Equation 20]

The screw constraint H is given by the following equation (21).

[0052]

[Equation 21]

The cylindrical constraint C is given by the following equation (22).

[0054]

[Equation 22]

The plane constraint E is given by the following equation (23).

[0056]

[Equation 23]

The ball restraint S is given by the following equation (24).

[0058]

[Equation 24]

The rotation constraint R, the advance constraint P, and the screw constraint H are 1
Dimension, cylindrical constraint C is two-dimensional, plane constraint E, sphere constraint S is 3
It becomes a dimensional linear space.

In the assembly shown in FIG. 4, the part 1 is a cylindrical restraint 1.
And is restrained by the cylindrical restraint 2. In this case S ₁ the linear space representing the possible movement in a cylindrical restraining 1, when the linear space representing the possible movement in a cylindrical restraining 2 and S _2, the possible movement of the component 1 intersection of S ₁ and S _2, Ie S ₁ US ₂
Which is calculated by the computer to be a translational motion in the direction of the restraint axis. Similarly, the part 3 is constrained by the cylindrical constraint 2 and the screw constraint 3. The movement of the screw restraint 3 is linear space S
_{It is determined} that S ₂ US ₃ represented by ₃ is a possible motion of the component 3, which is a screw motion of the restraints 2 and 3 along the Z axis. In this way, by performing the set operation in the linear space in the computer, the movement to be taken by each part during the assembly work is determined. That is, in the example of the components 1, 2, and 3, it is automatically determined that the component 1 is assembled by the translational motion in the Z-axis direction and the component 3 is assembled by the screw motion.

By the way, the state shown in FIG. 4 is in the process of assembling, not the final assembling state. In the example assembly of FIG. 1, another constraint must be added to the constraint previously given to represent the final assembly. That is, in addition to the cylindrical constraint between the components 1 and 2, it is necessary to apply the planar constraint in which the upper surface of the component 2 and the lower surface of the flange of the component 1 contact each other in the final state. A plane constraint is also applied between the parts 2 and 3. FIG. 5 shows the relationship of restraint between the respective parts. Part 1 during assembly
A cylindrical restraining C ₁ and part 2, part 2 and part 3 the cylindrical restraining C _1, component 3 and the component 1 screw restraint (5) a had been the is in the final assembly it to the plane constraint E _4, E ₅ Is added, the result is as shown in FIG. By adding a constraint for representing the final assembled state and determining the positional relationship as before, the final assembled state is determined. This is achieved by performing possible movements of each component from the previous relative positional relationship.

By the way, from the constraint of the final assembled state, the constraint that gives the final assembled state is omitted one by one. In the restraint state of FIG. 6, E ₄ and E ₅ are sequentially omitted.

First, if E ₄ is omitted, the component 3 becomes movable. This means that after assembling parts 1 and 2, part 3 is assembled. Then, if E ₃ is omitted, the component 1 becomes movable. If this is followed in reverse, the assembly order will be determined. That is, 1 is assembled to the component 2, and finally the component 3 is assembled.

On the contrary, if E ₃ is omitted first, the component 2
Can be moved, and then the part 1 (or the part 2, which may be considered as part 2) can be moved. From this, it is understood that if the component 3 is assembled to the component 1 and these are assembled to the component 2, the assembly is possible.

A flow chart of the above method is shown in FIG. First, in the constraint condition description 61, as described above, in CAD, the constraint number is given to the part diagram, the coordinates giving the position of the constraint on the component, and the constraint type are given to the computer as shown in FIG. That is, in the part 1 shown in FIG. 2, the constraint 1 is given as a cylindrical constraint, its position is given by coordinates X ₁ Z ₁ , and the constraint 2 is given as a cylindrical constraint X ₂ Y ₂ . During determination of the positional relationship during assembly 62, the computer creates the model of FIG. 3 from the CAD data determined in this way as described above, and determines the positional relationship between the parts during assembly. Next, in the determination 63 of the part operation at the time of assembly, the computer automatically determines the possible motions of the part at the time of assembly by the set operation of the linear space of the constraint as described above, and at the time of generating the addition order 64 of the final constraint , All cases of the addition order of the final constraint conditions are obtained, and in the assembly procedure generation 65, possible assembly procedures and the motion of the parts at that time are generated. From this result, the computer evaluated the assemblability 67,
The assembling property is evaluated (detailed in Japanese Patent Application No. 03-20675), and in the determination 66 of the optimum assembling procedure, the easiest assembling procedure is selected, and this is set as the optimum assembling procedure. Finally, the computer creates the automatic machine operation program 68 based on the optimum assembly procedure, the supply position of parts in the manufacturing line, and the line environment information such as the positional relationship between the line and the automatic machine.

[0066]

EFFECTS OF THE INVENTION By constructing a database in which a constraint during assembly and a constraint indicating the final assembly state are added to the parts constituting the assembly, the order of assembly of parts at the time of assembly and the assembly order It is possible to automatically determine the movements of the parts and the positional relationship of each part in the assembled state, and it is possible to build a support system for the assembly work plan by a computer. Also, if the force acting on each component does not become zero at the time of automatically calculating the positional relationship between each component, it means that there is a design error in that component, and it is also possible to check the dimensional error during design. It will be possible.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an assembly according to the present invention.

FIG. 2 is a diagram showing an example of constraint coordinates in CAD according to the present invention.

FIG. 3 is a diagram showing a restoring force model based on deviation based on CAD data according to the present invention.

FIG. 4 is a diagram showing a state during assembly according to the present invention.

FIG. 5 is a diagram showing a constraint relationship during assembly according to the present invention.

FIG. 6 is a view showing a restraint relationship in a final assembled state according to the present invention.

FIG. 7 is a diagram showing a processing flow of an assembly work plan computer support system according to the present invention.

[Explanation of symbols]

 1: component 1, 2: component 2, 3: component 3

Claims (3)

[Claims] 1. A constraint between parts of an assembly is input as a constraint during assembly and a constraint in a final assembly state, and a procedure for assembling parts or a time of assembling is input based on the inputted constraint between parts of the assembly. An assembly work plan computer support system characterized by generating motions of parts or both to support an assembly work plan. 2. A motion to be taken by a component during assembly is automatically generated based on a constraint condition during assembly.
Assembly work plan computer support system described. 3. The assembly work plan support computer system according to claim 1, wherein a possible assembly procedure is determined by generating a procedure for adding or deleting a constraint condition in the final assembly state.