KR101424753B1 - Method for Generalization of Flexible Multibody Dynamics System Modeling - Google Patents

Abstract

A multibody modeling method according to an embodiment of the present invention comprises the steps of: receiving an input defining a first body and a second body from an input interface; receiving an input defining a connection relationship between the first body and the second body from the input interface; receiving an input for changing properties of at least one of the first body and the second body from the input interface; and redefining the connection relationship if the properties are changed in a modeling module. The properties may be one of a rigid body, a fully flexible body, and a limited flexible body.

Description

Technical Field [0001] The present invention relates to a method of generalizing a flexible multibody dynamics system,

The present invention relates to a modeling and analysis method of a rigid body and a flexible body.

Flexible Multibody Dynamics System means a system in which one or more rigid bodies and flexible bodies are connected by joints, forces, and contact elements. Interpreting flexible multibody dynamics systems means analyzing systems such as automobiles, aircraft, ships, printers, etc. through mathematical modeling, where these rigid bodies and flexible bodies are connected.

In the analysis of flexible multibody dynamics systems, the assumptions and analytical methods required for the analysis vary greatly depending on the definition of the body that constitutes the system. Therefore, a good analysis requires a lot of experience and knowledge of the practitioner, and a high level of knowledge of the modeling solution, that is, the software.

The body constituting the system can be approximated as a rigid or flexible body. The body can be connected to each other by joint / force, contact elements. Particularly, depending on the type of body, the joint / force and contact elements are very diverse. In general, if you change the type of body, you must define a new joint / force or contact element that connects the body to the other body. However, this task requires the use of multiple solutions, or each joint / force or contact element is required for each change condition. In other words, it is difficult to encompass all the joints or contact elements suitable for the shape and material of the various bodies intended by the user in one solution, and this is a limitation of the software.

As described above, in the analysis of a conventional flexible multibody dynamical system, the use of various software is required, and a desired system analysis can be performed by understanding each software.

In order to solve this problem, it is an object of the present invention to provide an effective and easy modeling and analysis method for a system composed of a body, a joint, a force, a contact element and the like.

Particularly, since the modeling and analysis methods of joints, forces, and contact elements vary greatly according to the transformation of the body, the diversity and complexity increase, so that the modeling and analysis methods of these elements can be generalized to improve the convenience of modeling and analysis. do.

The objects of the present invention are not limited to those described above, and include intentions that may be referred to throughout the description of the invention or claims, or which can be easily grasped by those skilled in the art.

According to an aspect of the present invention, there is provided a method of modeling a multi-object according to an embodiment of the present invention, the method including receiving an input defining a first body and a second body at an input interface; Receiving at the input interface an input defining a connection relationship between the first body and the second body; Receiving at the input interface an input to change at least one attribute of the first body and the second body; And in the modeling module, redefining the connection relationship if the attribute is changed. In addition, the attribute may be one of a rigid body, a full flexible body (FFlex), and a reduced flexible body (RFlex).

Also, the fully flexible body may be generated from the rigid body using a mesh, and the constrained flexible body may be generated from the fully flexible body through an Eigen Value Analysis.

Wherein the connection relationship further comprises at least one of a joint or a force between the first body and the second body and a contact element and the step of redefining the connection relationship comprises: Force, and contact element.

In addition, when the attribute of the first body is changed from the rigid body to the fully flexible body or the limited flexible body, the step of redefining the connection relationship may include the step of redefining the connection relationship between the first body and the virtual body ); Connecting the modified flexible body and the first virtual body with a virtual flexible fixed joint; And defining the second body and the first virtual body according to the connection relationship.

And redefining the connection relationship when the attribute of the second body is changed from the rigid body to the fully flexible body or the limiting flexible body, ; Coupling the flexible body with the second virtual body and the virtual flexible fixed joint between the flexible body and the second virtual body; And defining the first virtual body and the second virtual body according to the connection relationship.

The first virtual body or the second virtual body may be a rigid body.

When the attributes of the first body or the second body are changed from a rigid body to a fully flexible body or a limited flexible body, the modeling module generates a rigid body element (RBE) at a previously generated joint position As shown in FIG.

Further, the contact surface of the rigid body may be divided into a triangle or a quadrangle, and the mesh of the fully flexible body or the limiting flexible body may have the shape of the triangle or the rectangle.

The step of redefining the connection relationship may define a contact element between a triangle or a quadrangle constituting the contact surface of the first body and a triangle or a quadrangle constituting the contact surface of the second body.

Further, according to one embodiment of the present invention, the above-described methods can be implemented by a computer-readable recording medium having recorded therein a program code for executing the method.

In accordance with various embodiments of the present invention, there is an effect that system analysis can be performed flexibly in a single solution by generalizing the elements related to the body and the body constituting the system.

In addition, the modeling process, which is processed internally, allows the user to change the attributes of the body according to the user's input, and to redefine the joint / force and connection elements that accompany it, There is an effect of eliminating.

1 is a conceptual diagram of a generalized body according to an embodiment of the present invention.
Fig. 2 is a diagram showing the property of a body to change a rigid body to a fully flexible body.
FIG. 3 is a conceptual diagram for generating a limiting elastic body through an Eigen Value Analysis. FIG.
FIG. 4 is an exemplary diagram illustrating a method of redefining a connection relationship of a general body using a virtual body.
5 is an exemplary conceptual diagram illustrating a method of redefining the connection relationship of a general body using general contact.
6 is an exemplary conceptual diagram of assist modeling that automatically generates a rigid body element when the attribute of the body changes from rigid to flexible.
7 is an exemplary conceptual diagram of assist modeling that automatically defines a contact surface when the attribute of the body changes from a rigid body to a flexible body.
Figure 8 shows an exemplary multibody modeling system in accordance with an embodiment of the present invention.
9 is a flow diagram illustrating a process in accordance with an embodiment of the present invention.

The system includes a plurality of bodies. Each body can be connected to each other using a joint. In other cases, each body may contact one another. The actual body may have attributes such as Rigid Body, Full Flexible Body (FFlex), and Reduced Flexible Body (RFlex) depending on its properties. This is an exemplary representation and different expressions may be used in each modeling solution. For example, a fully flexible body can be replaced by the same term as a general variant.

A rigid body means a body that is not deformed. When a body is defined as a rigid body, various parameters required for system analysis can be ignored or simplified. Therefore, it may be efficient to define all the components of the system as rigid bodies in the initial analysis of the system. Through dynamic analysis using a rigid body, the position, velocity, and acceleration of the body, and the force acting on the rigid body in each situation can be analyzed. The characteristics of the system can be analyzed from the information obtained through such dynamic analysis.

In fact, the bodies that make up the system are deformed. Therefore, a deformable body, that is, a flexible body, can be considered to interpret a more detailed physical phenomenon expected in the system. For example, a shaft bearing a load of a vehicle body may be deformed in the shape of a ship or a parabola. A tire which is able to withstand the load of the vehicle body can be deformed more freely than the axis. Accordingly, for one part constituting the system, force and boundary condition acting on the part can be defined and interpreted. This is called part analysis.

The maximum stress analysis is performed through the analysis of the part, and based on this, it is possible to review which part is vulnerable. Through the endurance analysis based on the results of this review, it is possible to reinforce areas where durability is weak or where stress is concentrated.

However, in fluid analysis, analysis time and interpretation difficulty are not suitable for freely applying the joint / force / contact elements used in general dynamics analysis. Deformation means that the degree of freedom is high, which means that there are many variables to consider. Therefore, flexible analysis requires more complicated operations on the number of cases that are increased compared to the dynamic analysis, which increases the modeling time (or rendering time of the system model).

In many cases, it is required to perform the modeling work while changing the properties of the body from a rigid body to a fully flexible body, or from a fully flexible body to a limiting body depending on the characteristics of the system. Of course, the user can change the properties of the body from a constrained flexible body to a rigid body, from a fully flexible body to a rigid body, or from a constrained flexible body to a fully flexible body. However, since a modeling solution suitable for performing a dynamic analysis using a rigid body and a modeling solution suitable for performing a dynamic analysis using a deformable body are different from each other, a separate solution suitable for each modeling is required for the user. For example, a kinematic analysis can be performed on one solution, and another solution can be further analyzed on a specific part based on the analysis result to integrate or separate the analysis results. Furthermore, each solution is not commonly used, and it is often the case that a significant degree of expertise and expertise is required to correctly use the solution.

According to the multibody modeling method according to an embodiment of the present invention, a system analysis considering a rigid body and a deformed body is performed based on a dynamic analysis. For example, as a first step, a dynamic analysis model for a system can be created and analyzed (system modeling / analysis).

As a second step, system modeling / interpretation can be used to determine whether a particular part of the system needs a fluid analysis. For example, if strong stress is concentrated on a particular part and the material or material of the part, or the shape of the part, is deemed to be deformed, or a stress exceeding a predetermined reference stress is applied to the part, Flexible analysis of the part may be required. If a flexible body analysis is required for a specific part, the part can be considered as a completely flexible body (FFLEX) and the analysis can be performed.

At this time, the generation of the fully flexible body can be generated by the solution used to perform the first step. Of course, it is also possible to create a fully flexible body with other Finite Element Analysis (FEA) software and reflect the results in the solution.

It takes a relatively long time to perform the analysis work after changing the properties of a specific body (part) to complete flexibility. This increases as the number of bodies considered as flexible increases. However, there may be parts which are not suitable for rigid body interpretation but which are relatively less deformable, and these parts can be interpreted as considering the limiting flexure described below.

As a third step, if a portion considered as a complete flexure can have a relatively small deformation, such a part can be treated as a constrained flexible body (RFLEX). The process of creating a fully flexible body with a limiting flexure may be performed by a solution used to perform the first step. Of course, other finite element analysis (FEA) software can also be used to create constraints from fully flexible and reflect these results in the solution. In this way, it is possible to drastically reduce the number of cases as compared with the case where all flexible bodies are considered as completely flexible bodies by performing analysis using a limiting flexible body, Efficiency is increased.

The performance of the above-described steps can be repeated. For example, the user can perform system analysis by constructing all the bodies constituting the system as a rigid body. After the primary analysis is completed, the user can perform a system analysis by changing a property of a part of the body, for example, a body corresponding to the first group, to a complete flexible body. Then, the user can perform the system analysis by changing the attribute of the part of the bodies included in the first group to the limiting flexible body again. Thereafter, the user can re-analyze some of the above-mentioned constrained bodies by modifying their properties into a rigid body or a completely flexible body. Alternatively, in addition to the analysis result performed for the first group, the body corresponding to the second group may be changed to a completely flexible body, and then the system analysis may be performed in a similar manner. Thus, in order to freely change the attributes of the body according to the progress of the system analysis, the following processing according to the attribute change of the body must be supported in the modeling system (solution). Hereinafter, a description will be given of a method for enabling subsequent processing according to a property change in a single solution even if the attribute of the body is changed.

In the following description, a system may be understood to mean a set of at least two interacting bodies. The system can have a hierarchical structure. For example, the vehicle system may include a subsystem such as a power system, a control system, and the like. Each subsystem may further include an additional subsystem, which may be defined by the user.

In addition, the process described below may be performed using a hardware processor such as a CPU, GPU, or AP. The processing units that perform each task can be understood as hardware modules. For example, an input interface for processing a user's input, such as a keyboard, a mouse, or a touch panel, is an input module, and a processor that performs system analysis based on input data is a modeling module, The display panel can be understood as a display module.

1 is a conceptual diagram of a generalized body according to an embodiment of the present invention. The general body 100 may have at least one property of a rigid body 110, a fully flexible body (FFLEX) 120, and a constrained flexible body (RFLEX) The user can define the attributes of the general body 100 as one of the rigid body 110, the fully flexible body 120, and the limit flexible body 130. The user may also change the attributes of the general body from one of the rigid body 110, the fully flexible body 120, and the constrained flexible body 130 to another. Hereinafter, the operation performed by the modeling module when receiving an input for changing the attribute of the general body 100 from a user will be described with reference to FIG. 2 to FIG.

Fig. 2 is a diagram showing the property of a body to change a rigid body to a fully flexible body. When the user defines the body attribute as the body 110, the modeling module regards the body as not deforming. Now, when the user changes the properties of the body from rigid to fully flexible, the modeling module can use the mesher to set the mesh on the rigid body. This operation may be implemented such that an appropriate mesh is automatically configured, or the mesh is configured with a size / number (i.e., scale) set by the user.

FIG. 2 shows an example of the transformation of a rigid body 210 using a mesh into a fully flexible body 220. 2, when the user inputs a body 210 having a rigid body attribute to a body 220 having a fully flexible body attribute, the modeling module can change the attribute of the body from a rigid body to a fully flexible body using a mesh have. In the example shown in FIG. 2, if the body having the fully flexible body attribute is changed to have the rigid body attribute again (i.e., the user changes the body property to the rigid body) It can be set that no deformation occurs or can be changed using existing rigid geometry or CAD information. The modeling module can then determine the body as a rigid body attribute and perform system analysis.

FIG. 3 is a conceptual diagram for generating a limiting elastic body through an Eigen Value Analysis. FIG. Unlike the fully flexible body, the restricted body is limited in its degree of deformation and its shape. The deformed shape of the body with the property of the limiting elastic body can be judged through the Eigenvalue analysis. For example, as shown in FIG. 3, when the linear body 310 is subjected to the eigenvalue analysis, the strain 320 according to the primary analysis result, the transformation 330 according to the secondary analysis result, And the deformation (340) according to the result of the third-order analysis. The interpretation shown in FIG. 3 is exemplary, and eigenvalue interpretation is possible for systems of various types and bodies containing the same. For example, when the rigid body 210 shown in FIG. 2 is analyzed considering the completely flexible body 220, when a force is applied to the right end, a proper deformation occurs in the right mesh structure. However, In the same case, the body can be transformed into a sinusoidal shape (e.g., transformation 330 according to the secondary analysis result in FIG. 3).

Taken together, the eigenvalue analysis can transform a fully flexible body into a limiting body. If the user changes the attribute of the body from the rigid body 110 to the limit flexible body 130, the modeling module sets the mesh for the body, transforms the body into the fully flexible body 120, The flexible body 130 can be deformed. The generated limit flexible body 130 may be changed to the fully flexible body 130 by using the previous information or using an inverse transformation or the like. It is also possible to generate a rigid body from the information if the CAD information corresponding to the constrained flexible body is stored or can be referred to.

If the properties of the body are changed from a constrained body to a rigid body, the modeling module can set that the constraining body is not deformed, as in the case of fully flexible bodies.

As described with reference to Figs. 1 to 3, the properties of the general body 100 can be changed from a rigid body to a completely flexible body or a limited flexible body, from a fully flexible body to a limiting flexible body or a rigid body, .

One body generally interacts with another body. System analysis can be performed considering the case where a body rotates around an arbitrary fixed point or a force such as an external force acts on a certain point in a system-independent manner, The system consists of multiple bodies, and interpreting the interaction between each body is an important part of the system analysis.

The joint between the body and the body can be connected. In general, a joint is the element that connects the body and the body. However, in one embodiment, without the definition of a joint, a force acting between the body and the body, or a force acting on the single body, can be defined. However, in other embodiments, both the joint and the force acting between the body and the body can be defined. In the following description, joint / force can be understood to mean at least one of a joint and a force.

The contact between the body and the body can be defined. Once the contact between the body and the body is defined, the interaction between the body and the body can be interpreted in such a way as to use general physical laws of force acting on the contact surface.

In this way, joints / forces and contacts can be used to define the connection between the body and the body. That is, defining the connection relationship between the body and the body can be understood as defining the joint / force or contact acting between the body and the body. Hereinafter, a method of defining a connection relationship between a body and a body when a property change occurs in a general body will be described with reference to FIGS. 3 and 4. FIG.

FIG. 4 is an exemplary diagram illustrating a method of redefining a connection relationship of a general body using a virtual body. In FIG. 4, for convenience of explanation, a general body is described as having a rigid body and a flexible body. That is, the flexible body shown in Fig. 4 means one of the limiting flexible body and the fully flexible body, but the principle shown in Fig. 4 can be applied to each flexible body.

In one embodiment, the first rigid body 410 and the second rigid body 420 may be connected by a joint. Or a force acting between the first rigid body 410 and the second rigid body 420 can be defined. For the sake of simplicity, we explain that the connection between two bodies is defined as a joint element.

When the attribute of the first rigid body 410 is changed to the first flexible body 412 by user input or the like, the previously defined connection relationship (i.e., joint element) is no longer changed between the first flexible body 412 and the second flexible body 412 It can not be used in the connection relation of the rigid body 420. In general, if a joint / force element is used as a connection relationship, a formalization is performed for the system analysis, and such a property transformation can not be done in a single system solution unless a pre-formulation has been performed for all cases. In other words, for the transformation of properties between a rigid-fully flexible body and a constrained body using a general body, the formulation of the joint / force component for nine cases is required. However, considering the amount of work required to perform the formalization in one case, a more efficient method is required to be improved.

To this end, when an input for changing the attribute of the first rigid body 410 to the first flexible body 412 is received, the modeling module determines whether the first rigid body 410 is connected to the second rigid body 420 A first virtual body 430, which is a type of dummy body whose mass is close to zero, is created. At this time, the property of the generated virtual body may be rigid. Accordingly, the second rigid body 420 can be connected to the first virtual body 430 according to the existing connection relationship. The modeling module connects the first virtual body 430 to the first flexible body 412. A virtual flexible fixed joint may be defined to define the connection relationship between the first virtual body 430 and the first flexible body 412. Since the virtual body connected to the flexible body is a constant dummy body, the connection between the flexible body and the virtual body can be defined with one virtual flexible fixed joint. In summary, the connection between a rigid body and a rigid body can be defined as a joint / force between existing rigid body and rigid body, and the connection between rigid body and flexible body can be defined as a virtual flexible fixed joint. In this way, the modeling module can redefine the joint relationship of the joint / force elements due to the attribute change of the general body by using the virtual body.

When the second rigid body 420 is now changed to the second flexible body 422, the modeling module creates the second virtual body 432 in the manner described above and connects it with the second flexible body 422 . The joint used may be a virtual flexible joint. In addition, the attribute of the second virtual body 432 may be rigid. Accordingly, the first virtual body 430 and the second virtual body 432 can be defined according to the existing connection relationship. Such a concept can be understood as a general joint / force.

In addition to the joints / forces described above, there is also a contact element that defines the connection relationship. In general, the kinds of contacts that can be used for system analysis have nine kinds, such as rigid-rigid contact and rigid-fully flexible contact, similar to the above joint elements. In general, when a contact element is created through rigid body modeling, the contact element must be newly defined by changing the body to a flexible body. Hereinafter, referring to FIG. 5, a generalized contact that enables system modeling and analysis using consistent elements even if the type of body changes is described.

5 is an exemplary conceptual diagram illustrating a method of redefining the connection relationship of a general body using general contact. Referring to FIG. 5, a rigid body can be divided into triangular or rectangular elements using faceting. Also, as described above, the fully flexible body and the limiting flexible body are already meshed, and such a mesh structure can be represented by a triangular or square element. For example, FIG. 5 illustrates a body 510 using a triangular structure and a body 520 using a square structure. Of course, it is also possible to set the body using a mixture of triangular and rectangular structures.

Since contact is a physical phenomenon that eventually occurs between the surface and the surface, the development of the contact element using the surface defined by the triangular and square elements enables the definition of the contact surface even if the properties of the body are changed. For example, a faceting for a body included in the system 530 may be performed 540 to define a contact surface of the system 530 including two rigid bodies. At this time, if the surface to be contacted is defined among the obtained triangular or rectangular elements, the system analysis can be performed using the force acting on the contact surface. Now, if the property of one of the rigid bodies is changed to a flexible body, the mesh of the corresponding flexible body will also have a triangular or rectangular shape, and the definition of the contact surface can be maintained. If deformation of the flexible body occurs due to the force applied to the contact surface, a surface is additionally brought into contact with or released from the contact, and the analysis of the surface can be performed using general physical laws.

The modeling module can perform actions according to the attribute change of the body using the general joint / force and / or general contact with respect to the general body described above. Furthermore, the modeling module can perform a function of effectively converting the modeling information according to the transformation of the body. This can be understood as a kind of assist modeling. For example, assist modeling includes the ability to process the joints / forces that are generated so that the joints / forces can be maintained consistently even when the body changes. Generally, a flexible body analysis is required to create a rigid body element (RBE) effectively at the position where joint / force is added. This will be described with reference to Fig.

6 is an exemplary conceptual diagram of assist modeling that automatically generates a rigid body element when the attribute of the body changes from rigid to flexible. 6, when the rotating body 610 and the pin 620 are both rigid bodies, for example, in the case of the rotating body 610 rotating around the pin 620, when rigid body modeling is performed, the rotating body 610 Is rotated about a rotational joint (i.e., pin 620). However, if the body property is changed from a rigid body to a full / restricted body 612, a virtual body must be created at the correct center of rotation to obtain appropriate analysis results. Generally, however, there is no appropriate geometry or node at that location, so creating a virtual rigid body (RBE) 622 at the critical joint / force location through assisted modeling will yield the desired analytical result . Finally, the rotational joint is defined between the virtual body formed between the pin 620 and the flexible body 612. A virtual flexible fixed joint is internally generated between the virtual body and the flexible body as described above. In this case, since the virtual body and the virtual flexible fixed joint are processed by the modeling module within the system solution, the user usually does not recognize the existence of the virtual body. That is, the user does not have to pay much attention to the complexity of such a connection relationship.

Also, in a general fluid analysis, the contact surface is defined at the portion where the contact occurs (or may occur). Therefore, it is necessary to automatically generate the contact surface effectively when the attribute of the body changes. The modeling module can prevent assist modeling from causing additional modeling due to body changes. This will be described with reference to FIG.

7 is an exemplary conceptual diagram of assist modeling that automatically defines a contact surface when the attribute of the body changes from a rigid body to a flexible body. Referring to FIG. 7, a contact surface 722 between rectangular parallelepiped bodies 720 having a rigid body property is defined similarly to the spherical body 710 having a rigid body attribute. When the shape of the rectangular body 720 is changed to the flexible body while the spherical body 710 maintains the rigid body property, the assist modeling is performed by newly defining the contact surface 724 of the flexible body so that the existing contact elements can be maintained do.

Figure 8 shows an exemplary multibody modeling system in accordance with an embodiment of the present invention. Referring to FIG. 8, the GUI refers to a graphical user interface. The solver can also be a variety of analysis solutions used for system modeling / analysis. The user now defines one or more bodies using a user interface such as a GUI. These inputs may be used by the geometry engine 810 to define the shape, location, material, strength, etc. of each body.

In general, the body initially created by the user is a rigid body, which is also desirable for initial analysis of the system. The generated rigid body can be changed to the fully flexible body (FFLEX) 822 by the mesh worker, that is, the mesh engine 820. A constrained flexible body (RFLEX) 832 can be generated by applying the eigenvalue analysis by the modal solution 830 to the completely flexible body 822 thus generated. Based on the rigid body analysis, the user can change the body attribute of the desired part to a fully flexible body or a limited body. In addition, as described above, it is also possible to generate a fully flexible body or a restricted body based on CAD information or the like derived from the outside of the multibody modeling system 800. If the properties of the body are changed at this time, the connection relationship between the bodies and the like can be redefined using the general joint / force 880 or the general contact 890 principle as described above.

When a system composed of a rigid body, a general flexible body, a constrained flexible body, and the like is constructed through repetition of the above operation, a stress result 860 (FIG. 8) is obtained through an interpretation such as a dynamic solution 840 or a multi- ), Through which endurance analysis and / or fatigue analysis 870 can be performed. The user can augment or improve the vulnerable portion of the system based on these results.

9 is a flow diagram illustrating a process in accordance with an embodiment of the present invention. In the description with reference to FIG. 9, the contents overlapping with those described above will be omitted. Also, in the flowchart shown in FIG. 9, the start and end may mean the start and end of some processes included in the overall process. In addition, each connection step may include additional processes, as is usual or as described above, unless otherwise specified.

Referring to FIG. 9, the multi-object modeling system receives an input defining at least one body through a user input interface (S910). In addition, the multibody modeling system receives, via a user input interface, an input defining a connection relationship between at least two bodies of the received bodies (S920). The user can change the attribute of the body that is determined to need to be changed through initial analysis or the like. This change input is also received through the user input interface (S930). The modeling module included in the multi-object modeling system may redefine the joint / force between the body and the body (S940) or redefine the contact (S942), or alternatively concurrently perform S940 and S942 Or sequentially. In this process, the aforementioned assist modeling can be performed together. Finally, when the connection relationship between the bodies is redefined (S950), the process can be terminated.

It will be appreciated by those skilled in the art that the block diagrams disclosed herein are conceptual representations of the circuitry for implementing the principles of the invention. Likewise, any flow chart, flow diagram, state transitions, pseudo code, etc., may be substantially represented in a computer-readable medium to provide a variety of different ways in which a computer or processor, whether explicitly shown or not, It will be appreciated by those skilled in the art. Therefore, the above-described embodiments of the present invention can be realized in a general-purpose digital computer that can be created as a program that can be executed by a computer and operates the program using a computer-readable recording medium. The computer-readable recording medium includes a storage medium such as a magnetic storage medium (e.g., ROM, floppy disk, hard disk, etc.), optical reading medium (e.g., CD ROM,

The functions of the various elements shown in the figures may be provided through use of dedicated hardware as well as hardware capable of executing the software in association with the appropriate software. When provided by a processor, such functionality may be provided by a single dedicated processor, a single shared processor, or a plurality of individual processors, some of which may be shared. Also, the explicit use of the term " processor "or" control unit "should not be construed to refer exclusively to hardware capable of executing software and includes, without limitation, digital signal processor May implicitly include memory (ROM), random access memory (RAM), and non-volatile storage.

In the claims hereof, the elements depicted as means for performing a particular function encompass any way of performing a particular function, such elements being intended to encompass a combination of circuit elements that perform a particular function, Or any form of software, including firmware, microcode, etc., in combination with circuitry suitable for carrying out the software for the processor.

Reference throughout this specification to " one embodiment " of the principles of the invention and various modifications of such expression in connection with this embodiment means that a particular feature, structure, characteristic or the like is included in at least one embodiment of the principles of the invention it means. Thus, the appearances of the phrase " in one embodiment " and any other variation disclosed throughout this specification are not necessarily all referring to the same embodiment.

In this specification, the expression 'at least one of' in the case of 'at least one of A and B' means that only the selection of the first option (A) or only the selection of the second listed option (B) It is used to encompass the selection of options (A and B). As an additional example, in the case of 'at least one of A, B and C', only the selection of the first enumerated option (A) or only the selection of the second enumerated option (B) Only the selection of the first and second listed options A and B or only the selection of the second and third listed options B and C or the selection of all three options A, B, and C). Even if more items are listed, they can be clearly extended to those skilled in the art.

The present invention has been described with reference to the preferred embodiments. It is to be understood that all embodiments and conditional statements disclosed herein are intended to assist one skilled in the art to understand the principles and concepts of the present invention to those skilled in the art, It will be understood that the invention may be embodied in various other forms without departing from the spirit or essential characteristics thereof. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (10)

In the multi-object modeling method,
Receiving an input defining a first body and a second body at an input interface;
Receiving at the input interface an input defining a connection relationship between the first body and the second body;
Receiving at the input interface an input to change at least one attribute of the first body and the second body; And
In a modeling module, redefining the connection relationship if the attribute is changed,
Wherein the attribute is one of a rigid body, a fully flexible body, a FFlex, and a reduced flexible body (RFlex). The method according to claim 1,
Wherein the fully flexible body is produced from the rigid body using a mesh,
Wherein the constrained flexible body is generated from the fully flexible body through Eigen Value Analysis. The method according to claim 1,
Wherein the connection relationship comprises at least one of a joint or force between the first body and the second body, and a contact element,
Wherein redefining the connection relationship redefines at least one of the joint or force, and the contact element. The method of claim 3,
Wherein if the attribute of the first body is changed from a rigid body to a fully flexible body or a limiting body,
Setting a first virtual body at a position connected to the second body from the first body;
Connecting the modified flexible body and the first virtual body with a virtual flexible fixed joint; And
And defining the second body and the first virtual body according to the connection relationship. 5. The method of claim 4,
Wherein when the attribute of the second body is changed from the rigid body to the fully flexible body or the limiting flexible body,
Setting a second virtual body at a position where the second body is connected to the first body;
Coupling the flexible body with the second virtual body and the virtual flexible fixed joint between the flexible body and the second virtual body; And
And defining the first virtual body and the second virtual body according to the connection relationship. 5. The method of claim 4,
Wherein the first virtual body or the second virtual body is a rigid body. The method according to claim 1,
When the attributes of the first body or the second body are changed from a rigid body to a fully flexible body or a limited flexible body, the modeling module may generate a rigid body element (RBE) at a previously generated joint position Further comprising the steps of: 3. The method of claim 2,
The contact surface of the rigid body may be divided into a triangle or a quadrangle,
Wherein the mesh of the fully flexible body or the limiting flexible body has a shape of the triangle or the rectangle. 9. The method of claim 8,
Wherein the redefining of the connection relationship defines a contact element between a triangle or a quadrangle constituting the contact surface of the first body and a triangle or a quadrangle constituting the contact surface of the second body. . A computer-readable recording medium having recorded thereon a program code for executing the method according to any one of claims 1 to 9.

Images