JPH05266147A - Mechanism analytic modeling system - Google Patents

Abstract

PURPOSE:To improve the precision of a mechanism analysis by automatically converting an inputted link mechanism analytic model into a model consisting of a loop including independent variables of an attitude analysis of a mechanism system. CONSTITUTION:This system has a figure display part 1 which displays a CAD diagram and is equipped with a CAD diagram input/output part 2 which generates display data and also analyzes input commands, an interface 3 which converts diagram data and data for analysis, an analytic input/output system 4 which converts analytic data and data dedicated to the analysis, and an analysis execution part 5. Then link data in analytic model data are generated according to data showing line elements of the CAD diagram displayed at the figure display part 1. When the loop including the independent variables can not be generated from existent links, the link is generated from data showing conditions where the links move in one body to generate the loop having conditions including the independent variables.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CAD diagram in a method or apparatus for directly performing a mechanism analysis of an object, an analysis model creation, an analysis condition input, and an analysis result display by being directly connected to an interactive CAD diagram creation system. The present invention relates to a system capable of generating a link mechanism analysis model capable of improving analysis accuracy from various mechanism system parts displayed in.

[0002]

2. Description of the Related Art In recent systems, a method of automatically generating a loop (a closed polygon formed by connecting links), which is one of analysis models, is often adopted. Therefore, only links and joints will be displayed in the analytical model. An example of a method for automatically generating loops is the ASME Mechanical Design Journal 1990 (Transactions oft).
he ASME journal of Mecanical Design). That is, all possible loops are generated from the data of links and joints by graph theory.
When selecting a loop for analysis from now on, the one having the smallest number of links constituting the loop will be selected. This is to prevent the coefficient matrix of the simultaneous equations, which is the equation created for each loop, from becoming a dense matrix. However, if the loop of the analysis model does not include the independent variable, the analysis accuracy may be significantly reduced.

[0003]

In the above-mentioned prior art, the mechanical system having a plurality of loops was not considered in terms of analysis accuracy, and the behavior of the mechanical system could not be predicted accurately.

An object of the present invention is to provide an analysis model with high analysis accuracy when various analysis models of mechanical parts are generated using the part shape data generated by the CAD drawing creation system.

[0005]

In order to achieve the above object, the present invention provides analysis model data based on data representing line elements in a CAD drawing which is a manufacturing drawing displayed on the screen of a terminal device. Generate link data for. Furthermore, loop data including an independent variable is generated from these link data. When a loop containing an independent variable cannot be created only by an existing link, a new link is created from the data indicating the condition that the links move together, and a loop that satisfies the condition containing the independent variable is created and displayed in a CAD diagram. It was made possible.

The mechanism analysis modeling system of the present invention is
As shown in the basic configuration of FIG. 1, a CAD diagram input / output which has a graphic display unit 1 for displaying a CAD diagram, is connected to the graphic display unit 1 to create display data, and analyzes input commands. Section 2, an interface 3 connected to the CAD diagram input / output section 2 for converting data of graphic data and analysis data, and connected to the interface 3 for data conversion of analysis data and analysis-specific data and various analyzes The analysis input / output system 4 connected to the execution unit 5 is included. Data conversion between analysis data and analysis-specific data is, for example, conversion of two-dimensional data to be analyzed into three-dimensional analysis-specific data, or two-dimensional analysis in order to visualize the analysis results obtained as three-dimensional data. It is to convert it into data.

[0007]

[Operation] The shape drawing (CAD) displayed on the screen of the terminal device
When an analysis model of an arbitrary mechanical part is defined above, loop data including independent variables in the analysis model based on the data representing the line element in the CAD diagram and it should be added in order to realize it Generate link data. Furthermore, the shape of the newly added link and loop is displayed.

[0008]

2 is a CAD diagram showing an example of a bill guide switching mechanism of a bank terminal device. In the figure, when the cam 6 rotates, the driven joint 7 swings left and right via the roller 8. As a result, the guide also rotates to the left and right to switch the banknote transport path. A spring 9 is attached to one end of the follower 7 on the side opposite to the attachment position of the follower roller 8, and the roller 8 is pressed against the surface of the cam 6. In addition, this mechanism is composed of a cam mechanism portion forming a cam / follower combination, a driven mechanism to which the follower roller 8 is attached, and a link mechanism portion including a restraining spring.

FIG. 3 shows a mechanism analysis model created using the CAD diagram of FIG.

The cam mechanism portion can be modeled by a loop P1 composed of links L1 to L4. The link mechanism unit can be modeled by a loop P2 including links L5 to L8.
Each link has two joints. For example,
L1 has joints J1 and J2 (hereinafter, this model is referred to as analysis model A).

Here, the link L3 and the link L5 are parts 2
It is a model of, and is a link that moves together.
That is, the common point J4 of the joints of the links
New link L9 connecting joints J5 and J3 other than
Also (indicated by dotted lines), exercises integrally with L3 and L5. Therefore, analysis of the motion of L9 instead of L5 is equivalent. In the analytical model shown in the figure, when the independent variable is J1, the loop P1 composed of L1 to L4 includes the independent variable, but the loop P2 composed of L5 to L8 does not include the independent variable.

Therefore, as shown in FIG. 4, an analytical model consisting of a loop including all independent variables is also equivalent to the analytical model A. In this model, a loop including L5 corresponding to the link L9 in FIG. 3 and L1 to L8 using a new link L8 connecting the fixed joints J1 and J7 is newly generated (hereinafter, this model is (Analysis model B). However, when the common point J4 is an independent variable, the analytical model A shown in FIG. 4 is adopted.

FIG. 5 shows a change with time in the position of the joint d at the fixed point obtained as a result of the dynamic analysis.
The analysis result 13 using the analysis model A and the analysis result 14 using the analysis model B have different values. In this case, originally,
About the coordinate value of the fixed point that should not move, analysis model B
In the analysis model A, the change is almost zero and the calculation is accurate, whereas in the analysis model A, there is a calculation error.

The cause of this error will be described below.

FIG. 6 shows the relationship between the angular displacement and the sliding displacement of the joint in the loop 1. When the link A rotates in the direction of the arrow, the triangle formed by the vector in the figure is established under the condition that the total change in the position of the joint a due to the displacement at the joints b, c, and d is 0. In the figure, ds
Reference symbol b indicates a slip displacement at the joint b, and dθc and dθd indicate angular displacements at the joints c and d, respectively. Similarly, FIG. 7 shows the relationship between the displacements of the joints d, e, and f in the loop 2 as a vector diagram under the condition that the total change in the position of the joint g is zero. Further, dsf is a slip displacement at the joint f, and dθd and dθe are angular displacements at the joints d and e, respectively.

It can be seen from the loop shape and the vector diagram that in the posture of the loop 2, dθd and dθe have substantially the same magnitude and opposite directions.

Here, the angular displacement of the joint g, which is the starting point of the posture analysis of the loop, does not appear in the vector diagram. Therefore, the angular displacement of the joint g is obtained by using the equation 1 in which the loop shape is closed.

[0018]

## EQU00001 ## d.theta.d + d.theta.e + d.theta.g = 0 (Equation 1) Here, since d.theta.g has a smaller change than d.theta.d and d.theta.e, it is considered that digit cancellation occurs when calculating the difference between d.theta.d and d.theta.e, resulting in an error in d.theta.g. ..

In the case of loop 1, the joint a which is the starting point
Is an independent variable and does not have this problem. On the other hand, in the case of the loop shape as shown in FIG. 8, the lengths of the links are almost the same, the magnitudes of the vectors are almost the same, and it is considered that there is no cancellation of digits.

Therefore, as shown in FIG. 9, a part is added to the system to judge whether the input loop shape needs to be changed to another loop.

By using this system, even an operator who has no knowledge of the relationship between the analysis model and the accuracy can improve the accuracy of the mechanism analysis.

[0022]

According to the present invention, a designer can perform accurate analysis without knowledge of the relationship between the mechanism analysis model and the precision of mechanism analysis, and therefore the efficiency of design calculation is improved without re-execution of analysis. be able to.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is an explanatory diagram of a guide switching mechanism of the bank automatic transaction device which is a target of the embodiment of the present invention.

FIG. 3 is an explanatory diagram of an analysis model input on the CAD diagram displayed in FIG. 2.

FIG. 4 is an explanatory diagram of an analysis model generated by this system.

FIG. 5 is an explanatory diagram of a difference caused in an analysis result due to a difference in the analysis model.

FIG. 6 is a vector diagram showing a change in position of a joint (joint a), which is a loop start point, due to the shape of the loop 1 of the analysis model A and displacement of each joint.

7 is a loop shape and vector diagram similar to FIG. 6 with respect to the shape of loop 2 with respect to loop 1 of FIG.

8 is a vector diagram showing a loop shape in which the loop shape is not changed with respect to the shape of FIG.

FIG. 9 is a flowchart of a determination process for determining whether to generate another loop based on the input analysis model.

[Explanation of symbols]

1 ... Graphic display part, 2 ... CAD figure input / output part, 3 ... Interface, 4 ... Analysis input / output part, 5 ... Analysis part.

Claims (1)

[Claims] 1. A system for generating a link mechanism analysis model based on a mechanism part shape displayed in the CAD diagram using a CAD diagram creation device, wherein the input link mechanism analysis model is equivalent to it. A mechanism analysis modeling system, which automatically converts the link mechanism analysis model configured by a loop including an independent variable in the posture analysis of the mechanism system.