WO2021083355A1

WO2021083355A1 - Three-dimensional parametric modeling method, and cooperation apparatus and 3d printing method therefor

Info

Publication number: WO2021083355A1
Application number: PCT/CN2020/125429
Authority: WO
Inventors: 白雪岭; 张鹏
Original assignee: 深圳先进技术研究院
Priority date: 2019-11-01
Filing date: 2020-10-30
Publication date: 2021-05-06
Also published as: CN110853136A; CN110853136B

Abstract

A three-dimensional parametric modeling method, and a cooperation apparatus and a 3D printing method therefor. The three-dimensional parametric modeling method comprises: acquiring three-dimensional data of a surface profile of an actually measured object (S10); according to the three-dimensional data of the surface profile of the actually measured object, performing registration processing on a constructed preset surface profile model, so as to acquire an actually measured surface profile model (S20); and according to the acquired actually measured surface profile model, building a cooperation model matching the actually measured object (S30). The three-dimensional parametric modeling method can rapidly and precisely construct a personalized cooperation model for a cooperation apparatus, and has the characteristics of having a high degree of automation and a relatively low technical requirement for technical staff, and facilitating the establishment of the standard of a personalized 3D printed medical product industry.

Description

Three-dimensional parametric modeling method, matching device and 3D printing method thereof

Technical field

The invention belongs to the technical field of 3D printing, and specifically relates to a three-dimensional parametric modeling method, a matching device and a 3D printing method thereof.

Background technique

At present, the medical fixation brace is placed outside the body to restrict certain movement of the body, thereby assisting the effect of surgical treatment, or directly used for external fixation of non-surgical treatment. Medical fixation supports mainly include forearm fixation supports, tibia and fibula fixation supports, cervical supports, thoracolumbar fixation supports and other fixed supports and adjustable knee supports, adjustable elbow supports and other adjustable cross-joint fixation Fixed braces, these fixed braces can effectively promote the auxiliary rehabilitation and motor function recovery after the treatment of bone and joint diseases, injuries and other diseases, and have important economic and social benefits.

The ideal fixation brace needs to meet the stable fixation of the fracture site or the fixed fixation of the movement limitation of the joint site. At present, the usual clinical practice is: (1) Use closed reduction with plaster bandages, small splints, and plastic polymer splints to fix limb fractures; (2) Use different types of standard cervical braces and thoracolumbar braces to fix the cervical spine and thorax Lumbar spine; (3) The knee/elbow joint is fixed with a universal adjustable fixed brace. The disadvantage of these methods is that the fixed brace cannot perfectly match the patient's personalized contour characteristics.

Three-dimensional printing technology has been applied to the production of fixed braces in clinical practice. It is completed through the three processes of "3D scanning-digital modeling-three-dimensional printing". The three-dimensional printing personalized fixed brace perfectly matches the patient's personalized contour characteristics and is more beautiful , Comfortable, lightweight, breathable, simple and reliable to wear. However, it also faces some obstacles. The shortcomings are: the digital model design of the fixed brace is based on commercial software, and modelers are required to personalize the fixed brace based on the patient's three-dimensional scan contours and build a personality based on past experience. The modeling process depends on the technical level and experience of technical personnel. Modeling requires high technical ability, which is difficult for ordinary technical personnel to grasp, and the level and accuracy of personalized design of different technical personnel The large difference makes it difficult to formulate the testing standards for 3D printing personalized products and the medical 3D industry standards, and it takes a long time to design and model personalized braces.

Summary of the invention

(1) The technical problem to be solved by the present invention

The technical problem solved by the present invention is: how to realize accurate and rapid automatic modeling of matching devices such as a fixed brace.

(2) Technical scheme adopted by the present invention

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A three-dimensional parametric modeling method, including:

Obtain the three-dimensional data of the surface profile of the measured object;

Performing registration processing on the constructed preset surface contour model according to the three-dimensional surface contour data of the measured object to obtain the measured surface contour model;

Establishing a matching model matching the actual measurement object according to the acquired actual measurement surface profile model.

Preferably, the method of performing registration processing on the constructed preset surface contour model according to the three-dimensional surface contour data of the actual measured object includes:

Perform initial size registration and secondary contour registration on the reference contour curved surface of the preset surface contour model according to the three-dimensional surface contour data of the actual measured object.

Preferably, the specific method of initial size registration includes:

Acquiring the actual anatomical features of the measured object according to the three-dimensional surface profile data;

The preset anatomical features of the preset surface profile model are adjusted according to the actual anatomical features to perform initial size registration between the reference profile curved surface and the actual profile curved surface of the measured object.

The specific method of secondary contour registration includes:

Acquiring a reference curve group that intersects the reference contour surface after initial size registration, and acquiring an actual curve group that intersects the actual contour surface of the measured object;

The reference curve group is approximated to the actual curve group, so that the reference contour surface after the initial size registration is close to the actual contour surface of the measured object.

Preferably, the method of establishing a matching model that matches the measured object according to the acquired measured surface profile model includes:

Obtain the parameterized relationship of the built fit model;

According to the parameterized relationship between the measured surface profile model and the matching model, a matching model matching the actual measurement object is established.

Preferably, the method for constructing the parameterized relationship of the coordination model includes:

Constructing the preset surface profile model;

Constructing a preset matching model that matches the preset surface profile model;

Constructing the parameterized relationship of the matching model according to the preset surface profile model and the preset matching model;

Wherein, the coordination model parameterization relationship includes a relative position constraint parameter variable group, a reference coordination curved surface node group control parameter group, and a structure size constraint parameter variable group.

Preferably, the method for constructing the relative position constraint parameter variable group includes:

Acquiring a preset anatomical feature according to the preset surface contour model;

The relative position constraint parameter variable group is constructed according to the preset anatomical features.

Preferably, the method for constructing the control parameter group of the reference matching curved surface node group includes:

According to the relative position constraint parameter variable group, the curved surface parameters of the preset surface profile model, and the mating curved surface parameters of the preset mating model, a reference mating curved surface node group control parameter group is constructed.

Preferably, the method for constructing the structural size constraint parameter variable group includes:

A structural size constraint parameter variable group is constructed according to the reference coordination curved surface node group control parameter group, the relative position constraint parameter variable group, and the topological structure parameters of the preset coordination model.

The invention also discloses a 3D printing method of the matching device, which includes:

Use the above-mentioned three-dimensional parametric modeling method to construct a matching model;

3D printing is performed according to the constructed matching model to obtain a matching device.

The invention also discloses a matching device, which is manufactured and formed by the above-mentioned 3D printing method.

(3) Beneficial effects

The invention discloses a three-dimensional parametric modeling method, a matching device and a 3D printing method thereof. Compared with the prior art, it has the following advantages and beneficial effects:

(1) Higher degree of automation. Compared with the prior art, 3D modeling must be performed every time 3D printing is performed. Since different types of preset surface profile models are constructed in advance in this application, the corresponding preset surface is adjusted according to the three-dimensional parameters of the fixed object to be fixed. The contour model can be adjusted to complete the establishment of the personalized matching model of the matching device. There is no need to re-establish a new 3D model every time. Compared with the existing technology, it has a higher degree of automation and the modeling process is faster. And precision.

(2) The requirements for technical personnel are relatively low. Since the existing 3D printing commercial software mainly models the scanned object, the process of constructing the corresponding 3D model of the corresponding device according to the 3D model of the object places high requirements on the operator and depends on the modeler The technical level and experience of the general modelling personnel are difficult to grasp. The preset surface profile model in this application is constructed in advance. In actual use, it is only necessary to adjust the preset surface profile model adaptively according to the three-dimensional data of the surface profile of the measured object to automatically complete the establishment of the personalized matching model. .

(3) Conducive to the establishment of industry standards. Using the solution of this application, various types of matching preset surface profile models and preset matching models can be established in accordance with unified standards. Different users only need to obtain the three-dimensional actual surface profile of the actual measured object in the actual operation process. Parameters, just adjust the pre-built model according to the three-dimensional parameters, which can provide favorable conditions for the formulation of industry standards for 3D printing personalized medical products.

Description of the drawings

Fig. 1 is a flowchart of a three-dimensional parametric modeling method according to an embodiment of the present invention;

Fig. 2 is a flowchart of constructing a cooperation model according to an embodiment of the present invention.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention can be implemented in many different forms, and the present invention should not be construed as being limited to the specific embodiments set forth herein. On the contrary, these embodiments are provided to explain the principle of the present invention and its practical application, so that other skilled in the art can understand various embodiments of the present invention and various modifications suitable for specific anticipated applications. The same reference numerals may be used to denote the same elements throughout the specification and the drawings.

In order to solve the technical problems raised in the background art, the basic idea of the technical solution of the present invention is: as an illustrative example, the knee joint of a normal human body is taken as an example, and the knee joint fixed brace matched with the knee joint is taken as an example. There is a human knee joint, and the preset surface contour model of the knee joint and the preset matching model of the matching fixed brace are pre-built. The preset matching model of the knee joint fixed brace can be parameterized along with the preset surface contour model of the knee joint化变。 Transformation. When the actual contour data of the knee joint of another human body is obtained, the pre-built preset surface contour model can be adjusted according to the actual contour data in three-dimensional registration, so that the knee joint can be parametrically transformed with the knee joint preset surface contour model The preset matching model of the fixed brace matches the actual contour of the knee joint, and a personalized three-dimensional model of the knee joint fixed brace can be established quickly and accurately.

Specifically, as shown in FIG. 1, the three-dimensional parametric modeling method of the embodiment of the present invention includes the following steps:

Step S10: Obtain the three-dimensional data of the surface profile of the measured object.

For specific measured objects, such as the parts that need to be fixed after treatment, such as the forearm, 3D scanning is used to scan the surface of the measured object to obtain the three-dimensional parameters of the actual surface profile of the measured object. Here, 3D scanning is the existing technology. I will not repeat them here.

Step S20: Perform registration processing on the constructed preset surface contour model according to the three-dimensional surface contour data of the measured object to obtain the measured surface contour model.

Specifically, the preset surface profile model refers to the surface profile model of the object to be fixed or matched by the matching device. Taking the medical field as an example, objects mainly refer to different parts of the human body that need to be fixed with a medical fixation brace, such as forearms, elbow joints, neck, torso, knee joints, calves, etc. Of course, this application is not limited to this. In other embodiments, it may be a different part of an animal.

This step is further described below by taking a human object as an example. Based on normal human body image data, a geometric model of various anatomical functional parts of the human body or a complete human body geometric model is constructed, and the surface contour model of the corresponding part can be obtained according to the geometric model, and different types of preset surface contour models can be obtained. The matching device mentioned in this application takes a medical fixed brace as an example. The fixed brace changes the mechanical distribution of the bones or muscles and ligaments of the affected part by fixing the associated limbs or torso surface, thereby assisting rehabilitation and motor function recovery. Therefore, determine the limb or trunk surface profile model associated with the fixed brace, and combine the requirements of auxiliary rehabilitation and motor function recovery that require fixation, including fixed angles, restricted joint mobility, etc., to construct the corresponding fixed brace.

Specifically, there is a certain degree of difference between the preset surface profile model used as a reference and the surface profile of the measured object, and registration processing is required to make the acquired measured surface profile model better match the surface profile of the measured object. Further, the specific method of registration processing is to perform initial size registration and secondary contour registration on the reference contour curved surface of the preset surface contour model according to the three-dimensional surface contour data of the actual measured object.

The specific methods of initial size registration include:

First, construct the preset anatomical features according to the preset surface profile model, establish the actual surface profile of the measured object according to the obtained three-dimensional parameters of the measured object, and obtain the actual anatomical features of the measured object according to the actual surface profile, and adjust the reference anatomy according to the actual anatomical features The corresponding parameters of the feature enable the reference contour surface of the preset surface contour model and the actual contour surface of the measured object to perform initial size registration. Among them, the methods for adjusting the corresponding parameters of the reference anatomical feature include translation transformation and rotation transformation based on anatomical feature points and feature axis, and scale transformation based on feature length.

The second contour registration step is further carried out. As a preferred embodiment, the reference contour surface of the preset surface contour model after the initial size registration and the actual contour surface of the measured object are respectively made a number of cross-sections that are equidistant and perpendicular to the anatomical axis to obtain the series respectively and the preset The set of curves intersecting between the reference profile surface of the surface profile model and the actual profile surface of the measured object, and further curve fitting these curve sets to obtain the reference curve group and the actual curve group respectively, and approximate the actual curve group through the reference curve group to achieve The reference contour surface of the preset surface profile model approximates the actual contour surface of the measured object, so that the quadratic contour registration of the reference contour surface of the preset surface profile model and the actual contour surface of the measured object can be realized. In this way, after the initial size registration and the secondary contour registration described above, the registration of the actual contour surface of the measured object with the reference contour surface of the preset surface contour model can be quickly and accurately realized.

In other embodiments, other algorithms can be used.

Step S30: Establish a matching model matching the measured object according to the acquired actual measured surface profile model.

Specifically, this step includes:

Step S31: Obtain the parameterized relationship of the constructed coordination model.

Furthermore, the parameterized relationship of the matching model represents the parameterized transformation relationship between the actual measured surface profile model and the matching model to be constructed. The method for constructing the parameterized relationship of the matching model includes: constructing the preset surface profile model; constructing a preset matching model matching the preset surface profile model; constructing based on the preset surface profile model and the preset matching model The parameterization relationship of the coordination model. Wherein, the coordination model parameterization relationship includes a relative position constraint parameter variable group, a reference coordination curved surface node group control parameter group, and a structure size constraint parameter variable group.

It should be noted that the existing technology can be used to construct a preset matching model matching the preset surface profile model, and at the same time, finite element analysis and actual clinical verification are used to verify the accuracy and effectiveness of the design. Among them, the existing technology uses 3D scanning and other methods to obtain the surface data of the object and build the surface profile model. Based on the surface profile model, the engineer uses personal technology to use special software to build the matching model. Each new object needs to repeat this process. . For this reason, our design idea is based on the design principle of the matching model, designing the modeling process of engineers, modeling parametric relationships, and applying algorithms to realize automatic modeling.

Specifically, the relative position constraint parameter variable group is first constructed. Acquire preset anatomical features according to the preset surface profile model, where the preset anatomical features include features such as feature points, feature axes, feature lengths, etc., and establish an association relationship between the preset anatomical features and the preset surface profile model, when When the preset surface profile model changes, the associated preset anatomical features will be parametrically transformed accordingly. The relative position constraint parameter variable group is further constructed according to the preset anatomical features, where the relative position constraint parameter variable group reflects the transformation relationship between each spatial feature point in the preset matching model and the feature parameters of the preset surface profile model. When the feature parameters of the surface profile model change, the corresponding spatial feature point parameters of the preset matching model will also be adaptively changed accordingly.

Secondly, construct the control parameter group of the datum matching surface node group. Specifically, a reference matching surface node group control parameter group is constructed according to the relative position constraint parameter variable group, the curved surface parameters of the preset surface profile model, and the matching surface parameters of the preset matching model. As a preferred embodiment, a number of cross-sections that are equidistant and perpendicular to the anatomical axis are made to obtain a series of curve sets that intersect the reference contour surface of the preset surface profile model and the mating surface of the preset mating model, and curve these curves are simulated. For example, perform B-spline curve approximation fitting to obtain the control parameter group of the series fitting curve. Further, based on the relative position constraint parameter group, the control parameter group of the series of fitting curves, and the relative spatial position relationship between the control parameter group of the series of fitting curves and the base point of the fitting model, the control parameter group of the reference fitting surface node group is constructed. The reference matching surface node group control parameter group reflects the change relationship between the surface parameters of the preset surface profile model and the matching surface parameters of the preset matching model. When the surface parameters of the preset surface profile model change, the preset The surface parameters of the matching model will also undergo adaptive changes.

Then, the structure size constraint parameter variable group is constructed. Specifically, a structural size constraint parameter variable group is constructed according to the control parameter group of the reference coordination curved surface node group, the relative position constraint parameter variable group, and the topological structure parameters of the preset coordination model. First, determine the structural size constant and parameter variable group of the preset matching model based on the control parameter group of the reference matching surface node group and the topological structure parameters of the preset matching model, and further constrain the parameter variables based on the parameter variable group and relative position of the structural size The group constructs the structural size constraint parameter variable group of the matching model. The structural size constraint parameter variable group reflects the change relationship between the topological structure size of the preset surface profile model and the preset matching model. When the preset surface profile model changes, the topological structure size parameters of the preset matching model will also be adaptable Variety. It should be noted that the structural size constants of the preset fit model include the constant size or set value in the preset fit model, such as the thickness of the preset fit model, the diameter of the hole and other constants, and the constants in the adjustable fixed support Constants such as the joint range of motion of the specific model.

By constructing the relative position constraint parameter variable group, the datum matching surface node group control parameter group and the structure size constraint parameter variable group, the parameters between the various parameters of the preset surface profile model and the parameters of the preset matching model can be established When the parameters of the preset surface profile model change, the spatial position, mating surface, and structure size of the preset mating model will also change accordingly.

Step S32: Establish a matching model matching the actual measurement object according to the parameterized relationship between the actual measurement surface profile model and the matching model.

According to step S20, after the registration process is performed on the preset surface profile model, the parameters of the preset surface profile model are substantially adjusted to obtain the measured surface profile model. According to step S31, it can be known that the parameterization of the matching model is constructed in advance. The measured surface profile model can automatically adjust the preset matching model through the parameterized relationship of the matching model, and then the matching model that matches the measured object can be obtained.

The application also discloses a 3D printing method of a matching device, which includes using the above-mentioned three-dimensional parametric modeling method to construct a matching model, and 3D printing according to the matching model to obtain a matching device. Here, 3D printing can be performed by using an existing 3D printer, which belongs to the existing technology.

The application also discloses a matching device, which is manufactured and formed according to the above-mentioned printing method.

The three-dimensional parametric modeling method disclosed in this application constructs preset surface profile models corresponding to various object types in advance, selects the corresponding preset surface profile models according to the type of the measured object, and uses the actual surface profile of the measured object Three-dimensional parameter adjustment preset surface profile model, thereby generating a matching model that matches the measured object. Compared with the prior art, the technical solution of this application has the following advantages:

The specific embodiments of the present invention are described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that without departing from the principle and spirit of the present invention whose scope is defined by the claims and their equivalents Under the circumstances, these embodiments can be modified and improved, and these modifications and improvements should also fall within the protection scope of the present invention.

Claims

A three-dimensional parametric modeling method, which is characterized in that it includes:

Obtain the three-dimensional data of the surface profile of the measured object;

Performing registration processing on the constructed preset surface contour model according to the three-dimensional surface contour data of the measured object to obtain the measured surface contour model;

Establishing a matching model matching the actual measurement object according to the acquired actual measurement surface profile model.
The three-dimensional parametric modeling method according to claim 1, wherein the method of performing registration processing on the constructed preset surface profile model according to the three-dimensional surface profile data of the actual measured object comprises:

Perform initial size registration and secondary contour registration on the reference contour curved surface of the preset surface contour model according to the three-dimensional surface contour data of the actual measured object.
The three-dimensional parametric modeling method according to claim 2, wherein the specific method of initial size registration comprises:

Acquiring the actual anatomical features of the measured object according to the three-dimensional surface profile data;

The preset anatomical features of the preset surface profile model are adjusted according to the actual anatomical features to perform initial size registration between the reference profile curved surface and the actual profile curved surface of the measured object.
The three-dimensional parametric modeling method according to claim 3, wherein the specific method of secondary contour registration comprises:

Acquiring a reference curve group that intersects the reference contour surface after initial size registration, and acquiring an actual curve group that intersects the actual contour surface of the measured object;

The reference curve group is approximated to the actual curve group, so that the reference contour surface after the initial size registration is close to the actual contour surface of the measured object.
The three-dimensional parametric modeling method according to any one of claims 1 to 4, wherein the method of establishing a matching model matching the measured object according to the acquired measured surface profile model comprises:

Obtain the parameterized relationship of the built fit model;

According to the parameterized relationship between the measured surface profile model and the matching model, a matching model matching the actual measurement object is established.
The three-dimensional parameterized modeling method according to claim 5, wherein the method for constructing the parameterized relationship of the coordination model comprises:

Constructing the preset surface profile model;

Constructing a preset matching model that matches the preset surface profile model;

Constructing the parameterized relationship of the matching model according to the preset surface profile model and the preset matching model;

Wherein, the coordination model parameterization relationship includes a relative position constraint parameter variable group, a reference coordination curved surface node group control parameter group, and a structure size constraint parameter variable group.
The three-dimensional parametric modeling method according to claim 6, wherein the method for constructing the relative position constraint parameter variable group comprises:

Acquiring a preset anatomical feature according to the preset surface contour model;

The relative position constraint parameter variable group is constructed according to the preset anatomical features.
The 3D parametric modeling method according to claim 7, wherein the method for constructing the control parameter group of the reference coordinated curved surface node group comprises:

According to the relative position constraint parameter variable group, the curved surface parameters of the preset surface profile model, and the mating curved surface parameters of the preset mating model, a reference mating curved surface node group control parameter group is constructed.
The three-dimensional parametric modeling method according to claim 8, wherein the method for constructing the structural size constraint parameter variable group comprises:

A structural size constraint parameter variable group is constructed according to the reference coordination curved surface node group control parameter group, the relative position constraint parameter variable group, and the topological structure parameters of the preset coordination model.
A 3D printing method with a device, which is characterized in that it comprises:

Use the three-dimensional parametric modeling method of any one of claims 1 to 9 to construct a coordination model;

3D printing is performed according to the constructed matching model to obtain a matching device.
A matching device, which is characterized in that it is manufactured and formed by the 3D printing method of claim 10.