Head meshing method and system based on the tno mannequin

Abstract

The application provides a head mesh partitioning method and system based on a TNO human body model, and comprises the following steps: step 1, setting an output.aps file in MADYMO software, and then extracting three Tait-Bryan angles in the.aps file when the head collides in MATLAB software; step 2, converting the three Tait-Bryan angles into a rotation matrix by using MATLAB; step 3, determining an axis-axis included angle between two coordinate systems; step 4, obtaining an axis-plane included angle of the two coordinate systems by using a stereographic method; step 5, calculating and outputting different head collision positions in MATLAB; and step 6, dividing the head collision positions into different latitudes and longitudes. The application solves the mutual conversion problem between software basic theory and actual models, and achieves the effect of mutual combination and application of the basic theory and software simulation.

Description

Technical Field

[0001] This invention relates to the field of mesh generation technology, and more specifically, to a method and system for head mesh generation based on the TNO human body model. Background Technology

[0002] Traffic accidents and workplace falls are frequent occurrences, leading to the widespread application of accident simulation based on MADYMO. The TNO human body model within the software is one of the internationally recognized human body models, representing a person in an accident. Head injuries are the most severe in these accidents, making research on protective devices such as helmets and the biomechanics of head injuries particularly important. Determining the location of head impact is a crucial parameter in standard helmet testing for collisions.

[0003] However, the existing technology (the article "Head impact conditions in the case of cyclist falls" published in the April 2012 issue of the journal "Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology", Volume 226, Issues 3-4, mentions a geometric partitioning method based on EN960 headform) is still limited to existing geometric models and cannot be applied to real human head models. This is because the simulation and the geometric head model are different, which leads to certain errors in the calculated head collision position. Furthermore, the final output position can only be marked on the geometric model as a collision point, and cannot be marked on the TNO model as a collision region. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a head mesh generation method and system based on the TNO human body model.

[0005] The head mesh generation method based on the TNO human body model provided by the present invention includes:

[0006] Step 1: Set the output to .aps file in the MADYMO software, and then extract the three Tait-Bryan angles from the head impact in the .aps file in the MATLAB software;

[0007] Step 2: Use MATLAB to convert the three Tait-Bryan angles into a rotation matrix R;

[0008] Step 3: Use the rotation matrix R in MATLAB to determine the axis-axis angle between the two coordinate systems;

[0009] Step 4: Using solid geometry, determine the axis-plane angle between the two coordinate systems based on the axis-axis angle;

[0010] Step 5: Calculate and output different head impact positions in MATLAB using the axis-plane angle;

[0011] Step 6: Based on the center point of the head of the TNO head-body model, divide the head impact location into different latitude and longitude coordinates.

[0012] Preferably, step 1 includes: the .aps file is a post-processing file in the MADYMO programming software, the three Tait-Bryan angles are three values ​​in the .aps file, and the output file type and category of the post-processing are set in the MADYMO program.

[0013] Preferably, step 2 includes:

[0014] Choose the rotation order of XYZ, and determine the rotation matrix given the Tait-Bryan angles. The formula for calculating the rotation matrix R is as follows:

[0015] R = R X ·R Y ·R Z …………(1)

[0016]

[0017]

[0018]

[0019] Among them, R X ,R Y and R Z It is a rotation matrix around the X, Y, Z axes; φ, η, and ξ are three Tait-Bryan angles.

[0020] Preferably, step 3 includes:

[0021] Rotated matrix The formula is as follows:

[0022]

[0023] Where i is the coordinate system before rotation, j is the coordinate system after rotation, and the value in equation (5) represents the cosine of the axis-axis angle before and after rotation.

[0024] Preferably, step 4 includes:

[0025] The formula for calculating the axial-plane angle β is as follows:

[0026]

[0027] Here, DE is an axis in the local coordinate system, and is a unit vector. The projection values ​​of DE onto the x and y axes are obtained from the rotated matrix. We obtain DF1 and DA as the cosines of the angle between the two axes.

[0028] The head mesh generation system based on the TNO human body model provided by the present invention includes:

[0029] Module M1: Set the output to .aps file in the MADYMO software, and then extract the three Tait-Bryan angles from the head impact in the .aps file in the MATLAB software;

[0030] Module M2: Uses MATLAB to convert the three Tait-Bryan angles into a rotation matrix R;

[0031] Module M3: Determining the axis-to-axis angle between two coordinate systems using the rotation matrix R in MATLAB;

[0032] Module M4: Using solid geometry, determine the axis-plane angle between two coordinate systems based on the axis-axis angle;

[0033] Module M5: Calculates and outputs different head impact positions in MATLAB based on the axis-plane angle;

[0034] Module M6: Based on the center point of the head of the TNO head-body model, the head impact location is divided into different latitude and longitude coordinates.

[0035] Preferably, the module M1 includes: the .aps file is a post-processing file in the MADYMO programming software, the three Tait-Bryan angles are three values ​​in the .aps file, and the output file type and category of the post-processing are set in the MADYMO program.

[0036] Preferably, the module M2 includes:

[0037] Choose the rotation order of XYZ, and determine the rotation matrix given the Tait-Bryan angles. The formula for calculating the rotation matrix R is as follows:

[0038] R = R X ·R Y ·R Z …………(1)

[0039]

[0040]

[0041]

[0042] Among them, R X ,R Y and R Z It is a rotation matrix around the X, Y, Z axes; φ, η, and ξ are three Tait-Bryan angles.

[0043] Preferably, the module M3 includes:

[0044] Rotated matrix The formula is as follows:

[0045]

[0046] Where i is the coordinate system before rotation, j is the coordinate system after rotation, and the value in equation (5) represents the cosine of the axis-axis angle before and after rotation.

[0047] Preferably, the module M4 includes:

[0048] The formula for calculating the axial-plane angle β is as follows:

[0049]

[0050] Here, DE is an axis in the local coordinate system, and is a unit vector. The projection values ​​of DE onto the x and y axes are obtained from the rotated matrix. We obtain DF1 and DA as the cosines of the angle between the two axes.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) By embedding a rotation matrix in the MATLAB program, the Tait-Bryan angle in the MADYMO theoretical manual is converted into the axial plane angle between the coordinate system of the TNO head model and the ground coordinate system in the software simulation. This solves the problem of mutual conversion between the basic software theory and the actual model, and achieves the effect of combining and applying the basic theory and the software simulation.

[0053] (2) By using the TNO head model in MADYMO software for accident simulation and network partitioning, the collision test points that are difficult to determine in industrial helmet testing were identified, and the input position of the head was determined when analyzing the biomechanics of complex collision damage. This solved the problems of difficult helmet testing in industry and difficult accurate analysis of head collision damage biomechanics, and realized the combination of medical-engineering interdisciplinary research and industry-academia-research collaboration. Attached Figure Description

[0054] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0055] Figure 1 This is a diagram illustrating the rotation principle of the Tait-Bryan angle.

[0056] Figure 2 This is a schematic diagram of the three-dimensional geometric projection principle.

[0057] Figure 3a The division of the head model in dimensionality. Figure 3b For the division of the head model in longitude, Figure 3c The overall diagram after the head model is divided;

[0058] Figure 4 This is a flowchart illustrating the implementation of the method of the present invention. Detailed Implementation

[0059] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0060] Example 1:

[0061] like Figure 4 This invention provides a head mesh generation method based on the TNO human body model, comprising the following steps:

[0062] Step 1: In the MADYMO software, set the output to a .aps file, and then extract the three Tait-Bryan angles from the head impact in the .aps file using MATLAB software, such as... Figure 1 .

[0063] Step 1 includes the following steps:

[0064] Step 1.1: The .aps file is a post-processing file in the MADYMO programming software. In the MADYMO program, you can set the output file type and category for post-processing.

[0065] Step 1.2: Based on the MADYMO theory manual, the three Tait-Bryan angles are the three values ​​in the .aps file.

[0066] Step 2: Use MATLAB to convert the three Tait-Bryan angles into rotation matrices. Choose the rotation order XYZ, and determine the rotation matrix given the Tait-Bryan angles. The formula for calculating the rotation matrix R is as follows:

[0067] R = R X ·R Y ·R Z …………(1)

[0068]

[0069]

[0070]

[0071] Among them, R X ,R Y and R Z It is a rotation matrix around the X, Y, Z axes; φ, η, and ξ are three Tait-Bryan angles.

[0072] Step 3: Use the rotation matrix R in MATLAB to determine the axis-axis angle between the two coordinate systems.

[0073] Rotated matrix The formula is as follows:

[0074]

[0075] Where i is the coordinate system before rotation, j is the coordinate system after rotation, and the value in equation (5) represents the cosine of the axis-axis angle before and after rotation.

[0076] Step 4: Using solid geometry, determine the axis-plane angle between the two coordinate systems based on the axis-axis angle, such as... Figure 2 As shown.

[0077] Suppose DE is an axis in the local coordinate system. Now find the angle between DE and the xy plane in the global coordinate system xyz.

[0078] The formula for calculating the axial-plane angle β is as follows:

[0079]

[0080] Where DE is a unit vector, DF1 and DA are the cosines of the angle between the two axes, and the projection values ​​of DE onto the x and y axes can be obtained from the rotated matrix. It was obtained from the middle.

[0081] Step 5: Calculate and output different head impact positions in MATLAB using the axis-plane angle.

[0082] Step 6: Divide the head impact location into different latitudes and longitudes based on the center point of the head of the TNO head-body model, as shown in Figure 3.

[0083] Step 6 includes the following steps:

[0084] Step 6.1: The TNO human body model is a validated and internationally recognized multi-rigid-body human body model in the MADYMO software. It is widely used in accidents such as car collisions and human falls. The code of the TNO human body model can be directly applied to the MADYMO software for programming and simulation.

[0085] Step 6.2: The head impact location is divided into 12 independent regions along the longitude (vertical) direction, spaced 30° apart, resulting in six symmetrical regions called Longitude1 to Longitude6. This division method is also applicable to the division of more longitude symmetrical regions; here, we only take the division into six symmetrical regions as an example.

[0086] Step 6.3: In the latitudinal (horizontal) direction, above line AA1, the head is divided into five regions at 18° intervals, named latitude1 to latitude5 (equiangular but not unequally spaced), based on the axial plane angle β. Below line AA1, the head is divided into two independent regions, latitude6 and latitude7. Latitude6 also has an 18° projection distance, and the rest are latitude7. This division method is also applicable to divisions with more latitudes; here, we only use a division with seven latitudes as an example.

[0087] The formula for calculating distance by latitude is as follows:

[0088]

[0089] Using the solution of this invention, in the event of accidents such as vehicle-pedestrian collisions and workplace falls, the impact point of the human head when it collides with the ground can be accurately located. These impact points can be used for further biomechanical damage research in medicine and can also help in the design of helmets and the definition of helmet testing standards in industry.

[0090] Example 2:

[0091] The present invention also provides a head mesh generation system based on the TNO human body model. The head mesh generation system based on the TNO human body model can be implemented by executing the process steps of the head mesh generation method based on the TNO human body model. That is, those skilled in the art can understand the head mesh generation method based on the TNO human body model as a preferred embodiment of the head mesh generation system based on the TNO human body model.

[0092] The head mesh generation system based on the TNO human body model provided by the present invention includes: Module M1: setting the output .aps file in MADYMO software, and then extracting the three Tait-Bryan angles at the time of head impact in the .aps file in MATLAB software; Module M2: using MATLAB to convert the three Tait-Bryan angles into a rotation matrix R; Module M3: using the rotation matrix R in MATLAB to determine the axis-axis angle between two coordinate systems; Module M4: using solid geometry to calculate the axis-plane angle between the two coordinate systems based on the axis-axis angle; Module M5: calculating and outputting different head impact positions in MATLAB based on the axis-plane angle; Module M6: dividing the head impact position into different latitudes and longitudes based on the head center point of the TNO head human body model.

[0093] The module M1 includes: the .aps file is the post-processing file in the MADYMO programming software, the three Tait-Bryan angles are the three values ​​in the .aps file, and the output file type and category of the post-processing are set in the MADYMO program.

[0094] The module M2 includes:

[0095] Choose the rotation order of XYZ, and determine the rotation matrix given the Tait-Bryan angles. The formula for calculating the rotation matrix R is as follows:

[0096] R = R X ·R Y ·R Z …………(1)

[0097]

[0098]

[0099]

[0100] Among them, R X ,R Y and R Z It is a rotation matrix around the X, Y, Z axes; φ, η, and ξ are three Tait-Bryan angles.

[0101] The module M3 includes:

[0102] Rotated matrix The formula is as follows:

[0103]

[0104] Where i is the coordinate system before rotation, j is the coordinate system after rotation, and the value in equation (5) represents the cosine of the axis-axis angle before and after rotation.

[0105] The module M4 includes:

[0106] The formula for calculating the axial-plane angle β is as follows:

[0107]

[0108] Here, DE is an axis in the local coordinate system, and is a unit vector. The projection values ​​of DE onto the x and y axes are obtained from the rotated matrix. We obtain DF1 and DA as the cosines of the angle between the two axes.

[0109] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0110] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A head mesh generation method based on the TNO human body model, characterized in that, include: Step 1: Set the output to .aps file in the MADYMO software, and then extract the three Tait-Bryan angles from the head impact in the .aps file in the MATLAB software; Step 2: Use MATLAB to convert the three Tait-Bryan angles into a rotation matrix R; Step 3: Use the rotation matrix R in MATLAB to determine the axis-axis angle between the two coordinate systems; Step 4: Using solid geometry, determine the axis-plane angle between the two coordinate systems based on the axis-axis angle; Step 5: Calculate and output different head impact positions in MATLAB using the axis-plane angle; Step 6: Based on the center point of the head of the TNO head-body model, divide the head impact location into different latitude and longitude coordinates; Step 2 includes: Choose the rotation order of XYZ, and determine the rotation matrix given the Tait-Bryan angles. The formula for calculating the rotation matrix R is as follows: …………(1) …………(2) …………(3) …………(4) in, , and It is a rotation matrix around the X, Y, Z axes; , and There are three Tait-Bryan angles; Step 3 includes: Rotated matrix The formula is as follows: …………(5) in, It is the coordinate system before rotation. It is the rotated coordinate system, and the value in equation (5) represents the cosine of the axis-axis angle before and after rotation; Step 4 includes: Axial-face angle The calculation formula is as follows: …………(6) Here, DE is an axis in the local coordinate system, and is a unit vector. The projection values ​​of DE onto the x and y axes are obtained from the rotated matrix. Obtained from; DA is the cosine of the angle between the two axes.

2. The head mesh generation method based on the TNO human body model according to claim 1, characterized in that, Step 1 includes: the .aps file is the post-processing file in the MADYMO programming software, the three Tait-Bryan angles are the three values ​​in the .aps file, and the output file type and category are set in the MADYMO program.

3. A head mesh generation system based on the TNO human body model, characterized in that, include: Module M1: Set the output to .aps file in the MADYMO software, and then extract the three Tait-Bryan angles from the head impact in the .aps file in the MATLAB software; Module M2: Uses MATLAB to convert the three Tait-Bryan angles into a rotation matrix R; Module M3: Determining the axis-to-axis angle between two coordinate systems using the rotation matrix R in MATLAB; Module M4: Using solid geometry, determine the axis-plane angle between two coordinate systems based on the axis-axis angle; Module M5: Calculates and outputs different head impact positions in MATLAB based on the axis-plane angle; Module M6: Based on the center point of the head of the TNO head-body model, the head impact location is divided into different latitude and longitude coordinates; The module M2 includes: Choose the rotation order of XYZ, and determine the rotation matrix given the Tait-Bryan angles. The formula for calculating the rotation matrix R is as follows: …………(1) …………(2) …………(3) …………(4) in, , and It is a rotation matrix around the X, Y, Z axes; , and There are three Tait-Bryan angles; The module M3 includes: Rotated matrix The formula is as follows: …………(5) in, It is the coordinate system before rotation. It is the rotated coordinate system, and the value in equation (5) represents the cosine of the axis-axis angle before and after rotation; The module M4 includes: Axial-face angle The calculation formula is as follows: …………(6) Here, DE is an axis in the local coordinate system, and is a unit vector. The projection values ​​of DE onto the x and y axes are obtained from the rotated matrix. Obtained from; DA is the cosine of the angle between the two axes.

4. The head mesh generation system based on the TNO human body model according to claim 3, characterized in that, The module M1 includes: the .aps file is the post-processing file in the MADYMO programming software, the three Tait-Bryan angles are the three values ​​in the .aps file, and the output file type and category of the post-processing are set in the MADYMO program.

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