Plate spring steering axle tire envelope generation method and device based on Catia

Abstract

The invention discloses a plate spring steering axle tire envelope generation method and device based on Catia, and relates to the technical field of three-dimensional modeling. The method comprises the steps of receiving a reference selection instruction input by a user based on a preset user interaction interface; inputting the reference selection instruction into CATIA to create skeleton parts corresponding to the reference selection instruction, and associating the skeleton parts to form a motion mechanism skeleton model; based on a preset constraint rule, performing driving constraint on the motion mechanism skeleton model to establish a motion pair corresponding to a skeleton part in the motion mechanism skeleton model, and generating a motion mechanism with a standard degree of freedom; and calculating a maximum steering angle and a movement track of the tire based on the movement mechanism so as to generate a tire envelope. According to the method, secondary development is carried out on the CATIA, a user does not need to manually set a kinematic pair through a built-in constraint rule and an automatic process, and full-automatic, efficient and high-consistency generation of the tire envelope of the plate spring steering axle is achieved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of three-dimensional modeling, in particular to a Catia-based spring steering axle tire envelope generation method. BACKGROUND

[0002] In the chassis design of a commercial vehicle, a steering axle with a leaf spring structure is a common form. In order to ensure that the tire does not interfere with the surrounding components (such as a vehicle frame, a brake pipeline, etc.) under steering and bumping conditions, the motion trajectory of the tire must be accurately calculated and an envelope body thereof must be generated. The envelope body is a key basis for chassis component layout and clearance checking.

[0003] At present, a digital motion simulation method is usually used to complete this work. A designer needs to manually assemble all moving parts such as a steering knuckle, an axle, and a leaf spring one by one in a CATIA three-dimensional design software, and define complex motion pairs for them to simulate real motion relationships. This method has the following significant shortcomings: first, the entire setting process is tedious, time-consuming, and prone to errors, and requires high software operation skills and mechanism knowledge of the engineer; second, the degrees of freedom of the motion mechanism must be accurately ensured to be zero, otherwise the simulation cannot be performed or the result is distorted; and finally, manual operation cannot guarantee the consistency and reliability of the design results, and the quality of the envelope bodies obtained by different engineers or different projects may be uneven.

[0004] Therefore, how to secondarily develop the CATIA three-dimensional design software to automatically generate a leaf spring steering axle tire envelope becomes a technical problem to be solved. SUMMARY

[0005] Embodiments of the application provide a Catia-based leaf spring steering axle tire envelope generation method and device to solve the technical problem of how to secondarily develop the CATIA three-dimensional design software to automatically generate a leaf spring steering axle tire envelope.

[0006] In a first aspect, embodiments of the application provide a Catia-based leaf spring steering axle tire envelope generation method, which includes: receiving a reference selection instruction input by a user based on a preset user interaction interface; inputting the reference selection instruction into the CATIA to create a skeleton part corresponding to the reference selection instruction and associating the skeleton part to constitute a motion mechanism skeleton model; driving and constraining the motion mechanism skeleton model based on a preset constraint rule to establish a motion pair corresponding to the skeleton part in the motion mechanism skeleton model and generate a motion mechanism with a standard degree of freedom; and calculating a maximum steering angle and a motion trajectory of the tire based on the motion mechanism to generate a tire envelope.

[0007] In a second aspect, the embodiments of the present application also provide a device for generating a tire envelope of a leaf spring steering axle based on Catia, which comprises: a reference selection module, configured to receive a reference selection instruction input by a user based on a preset user interactive interface; wherein the reference selection instruction comprises axis information of the leaf spring steering axle, reference point information and a U-shaped bolt installation distance parameter; a motion mechanism skeleton creation module, configured to input the reference selection instruction into CATIA to create a skeleton part corresponding to the reference selection instruction, and associate the skeleton part to form a motion mechanism skeleton model; a motion mechanism creation module, configured to drive and constrain the motion mechanism skeleton model based on a preset constraint rule to establish a motion pair corresponding to the skeleton part in the motion mechanism skeleton model, and generate a standard degree of freedom motion mechanism; and a motion envelope generation module, configured to calculate a maximum steering angle and a motion trajectory of the tire based on the motion mechanism to generate a tire envelope.

[0008] The method and device for generating a tire envelope of a leaf spring steering axle based on Catia provided by the embodiments of the present application have the following beneficial effects: by using a preset user interactive interface, a motion mechanism skeleton model can be automatically generated, a motion pair can be created, a maximum steering angle of a tire can be calculated, and a tire envelope body can be generated only by selecting key references by a user, without manual setting by the user, thereby reducing manual intervention, avoiding omissions or errors caused by manual simulation, enabling non-professional simulation personnel to quickly complete tire envelope analysis, supporting temporary creation of a follow-up part, and enabling the generated tire envelope body to be converted into an editable multi-curved surface feature part, thereby enhancing the flexibility and adaptability of operation. BRIEF DESCRIPTION OF DRAWINGS

[0009] The accompanying drawings, which are included to provide a further understanding of the present application, constitute a part of the present application and illustrate the illustrative embodiments of the present application and their description serve to explain the present application, but do not limit the present application. In the drawings:

[0010] Figure 1 A method for generating a tire envelope of a leaf spring steering axle based on Catia is provided in the embodiments of the present application;

[0011] Figure 2 A reference position diagram of a motion mechanism is provided in the embodiments of the present application;

[0012] Figure 3 A method for obtaining a reference and a software startup main interface are provided in the embodiments of the present application;

[0013] Figure 4 An interactive interface for creating an associated element is provided in the embodiments of the present application;

[0014] Figure 5The method for creating a motion envelope and the interactive interface provided by the embodiments of the present application;

[0015] Figure 6 The method for converting an.stl file into a curved surface feature part drawing provided by the embodiments of the present application; DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in detail with the embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative work fall within the scope of protection of the present application.

[0017] The embodiments of the present application provide a method and device for generating a plate spring steering axle tire envelope based on CATIA, to solve the technical problem of how to develop CATIA three-dimensional design software to automatically generate a plate spring steering axle tire envelope.

[0018] The technical solutions provided by the embodiments of the present application will be described in detail below with the drawings.

[0019] The method provided by the embodiments of the present application is applied in CATIA software. CATIA is a three-dimensional computer-aided design / aided manufacturing application software developed by Dassault Systemes of France, which includes the following modules: design modules such as part design, assembly design, wireframe and surface design, and shape generation design, supporting from simple part modeling to complex surface design; engineering modules including engineering drawing, sheet metal design, and mechanical design, etc., which can automatically generate two-dimensional views from three-dimensional models and provide rich labeling and annotation functions; analysis modules mainly cover finite element analysis and simulation, the finite element analysis module can be used for structural, thermal, fluid, and other multi-physical field analysis of parts and assemblies, providing functions such as meshing, boundary condition setting, etc., the simulation module provides functions such as motion simulation, dynamics simulation, etc., supporting the creation and testing of virtual prototypes; manufacturing modules including numerical control machining and mold design, etc., the numerical control machining module is used to generate numerical control machining programs, supporting various machining methods and tool path generation, the mold design module is used for mold design and analysis, supporting mold cavity, core, and other designs; the data management module provides product data management and knowledge engineering functions, the product data management module is used to manage product data including design files, engineering drawings, etc., providing functions such as version control, permission management, etc., the knowledge engineering module is used to encapsulate and reuse design and engineering knowledge, improving design efficiency and quality.

[0020] Figure 1A Catia-based plate spring steering axle tire envelope generation method flow chart is provided for the embodiments of the application. As shown in Figure 1 The Catia-based plate spring steering axle tire envelope generation method provided by the embodiments of the application specifically comprises the following steps:

[0021] Step 10: Based on the preset user interaction interface, the reference selection instruction input by the user is received.

[0022] As an optional embodiment, based on the preset user interaction interface, the reference selection instruction input by the user is received, which specifically can comprise: step 101: based on the preset reference geometric element type selection field in the CATIA user interaction interface, the axis information, the reference point information and the U-shaped bolt mounting distance parameter selected by the user are received.

[0023] In this step, in the user interaction interface, the explicit reference geometric element type selection field is preset, which is specially used for receiving the key reference information selected by the user for the plate spring steering axle related model, which comprises the axis information, the reference point information and the U-shaped bolt mounting distance parameter, Figure 2 A motion mechanism reference position diagram provided by the embodiments of the application is shown, which comprises a U-shaped bolt mounting distance 26, the axis information comprises a kingpin 21, a plate spring limiting surface 27 and a frame limiting surface 28, the reference point information comprises a steering trapezoid 22, a rear lug ear rotating shaft axis 23, a rear lug ear center 24, a main piece center 25 and a front lug ear center 29; when the user starts the software and enters the reference selection link, the user can select the key reference information through the reference geometric element type selection field in the user interaction interface, Figure 3The software startup main interface shown is used for field selection, accurate selection of required axis information in an opened part or assembly model, and the axis information is used as important space positioning basis for subsequent construction of a motion mechanism skeleton model and provides basic support for reasonable motion trajectory planning of a motion part. Meanwhile, the reference point information selection field of the interface supports selection of multiple reference points from the model by a user, the reference points are distributed at different key positions of the leaf spring steering bridge, are core references for determining relative position relationships of parts and ensuring accurate construction of a motion mechanism, and ensure that the motion mechanism skeleton model generated subsequently can accurately reflect the space layout and connection relationship of actual parts. In addition, the interface is also provided with a special U-shaped bolt installation distance parameter input field, and a user needs to accurately input the installation distance parameter of the U-shaped bolt in the leaf spring steering bridge in the field. The parameter is directly related to the assembly accuracy of the leaf spring and related parts, has an important influence on the stability of the subsequent motion mechanism and the accuracy of the tire motion envelope, and is one of key parameters for ensuring smooth development of the entire leaf spring steering bridge design and checking work. All selected or input reference information is displayed in the corresponding parameter display area of the interface in real time after the user completes the operation, which facilitates the user to intuitively check and check, ensures that the selected reference information is accurate, and lays a reliable foundation for subsequent automatic creation of a motion mechanism skeleton model, generation of a tire motion envelope and the like.

[0024] Step 102: verifying whether the axis information meets the rotation space requirement of the tire, verifying whether the reference point information constitutes a complete leaf spring motion chain topology structure, and verifying whether the U-shaped bolt installation distance parameter is within a preset feasible range.

[0025] In this step, the compliance and adaptability of the axis information, the reference point information and the U-shaped bolt installation distance parameter selected by the user are verified respectively. The axis information verification is around the tire rotation space requirement, analyzes the matching degree of the axis position, extension direction and the tire rotation track in combination with the structure characteristics of the leaf spring steering bridge, judges whether sufficient rotation space can be provided to avoid space limitation of the tire in simulation motion, and excludes interference hidden dangers for accurate generation of a tire motion envelope surface. The core of the reference point information verification is to judge whether a complete leaf spring motion chain topology structure can be constituted, analyzes the reference point correlation according to the connection relationship and motion logic of parts, checks whether key nodes are covered and whether relative positions meet the mechanical principle and structure requirement, provides reliable node support for automatic creation of a motion mechanism skeleton model, and ensures accurate simulation of the actual motion of the leaf spring. The U-shaped bolt installation distance parameter verification compares the parameter with design specifications, assembly process requirements and part adaptability, automatically calls data verification, and the parameter is within the range, which meets the assembly accuracy requirement and ensures the motion stability of the leaf spring. If the parameter exceeds the range, an exception needs to be adjusted, which avoids affecting the operation of the leaf spring motion chain and the accuracy of the tire envelope.

[0026] Step 103: output the verified axis information, datum point information and U-bolt installation distance parameters to obtain a datum selection instruction.

[0027] In this step, when the axis information, datum point information and U-bolt installation distance parameters all pass the aforementioned verifications, a final datum selection instruction is generated. First, all the verified datum information is integrated, and the integrated datum information is packaged according to a preset instruction generation rule. In the packaging process, the type, corresponding functional attribute and calling priority in subsequent motion mechanism creation of each datum information are clearly marked to ensure that the datum selection instruction can clearly convey the core role and use logic of each datum information. Second, the packaged datum information is output in the form of a datum selection instruction, which directly interfaces with the subsequent motion mechanism creation module, so that the motion mechanism creation process can accurately retrieve the verified axis, datum point and U-bolt installation distance parameters, providing accurate and complete datum data support for automatically generating a motion mechanism skeleton model that meets design requirements, and ensuring smooth start and efficient promotion of the subsequent tire motion envelope generation process.

[0028] Step 20: input the datum selection instruction into CATIA to create a skeleton part corresponding to the datum selection instruction, and associate the skeleton part to form a motion mechanism skeleton model.

[0029] As an optional embodiment, the datum selection instruction is input into CATIA to create a skeleton part corresponding to the datum selection instruction, and the skeleton part is associated to form a motion mechanism skeleton model, which can specifically include: step 201: identifying the environment type of CATIA.

[0030] In this step, after the datum selection instruction is input into CATIA, the design environment of the current CATIA software needs to be determined first to ensure that the subsequent operation can adapt to the corresponding environment logic and functional module. The software reads the environment attribute information of the currently opened model by calling the API interface related to CATIA, and accurately judges whether the current environment type belongs to the part design environment or the assembly design environment according to the inherent differences in data structure and functional identification between the CATIA part design environment and the assembly design environment.

[0031] Step 202: when the environment type is a part design environment, convert the part design environment to an assembly design environment.

[0032] In this step, if the current environment type is identified as a part design environment, the environment conversion mechanism is automatically triggered to convert the part design environment to an assembly design environment. This conversion operation is automatically performed by CATIA according to the preset program logic without manual intervention by the designer. The purpose is to provide an adaptive environment foundation for subsequent creation of the mechanism skeleton model, because the construction of the mechanism skeleton model needs to rely on the multi-component management and motion relationship definition functions of the assembly design environment. The part design environment cannot meet the multi-component collaboration and correlation logic requirements of the mechanism. In the conversion process, it is necessary to ensure the complete retention of the original part model geometry data and feature information to avoid data loss or damage due to environment conversion. At the same time, the initialization setting of the assembly design environment is automatically completed to prepare for the subsequent creation of the mechanism skeleton component based on the datum information, ensuring the coherence and stability of the entire automation process.

[0033] In one embodiment, the part design environment is converted to the assembly design environment, and the code implementation can be as follows:

[0034] if CATIA.GetWorkbenchId<>"Assembly"then

[0035] catia.StartWorkbench("Assembly")

[0036] end if

[0037] Step 203: Based on the datum selection instruction, the coordinate mapping is used to generate the position correspondence relationship between the datum selection instructions.

[0038] In this step, first, the unified coordinate system of the CATIA model space is taken as the reference datum, and the coordinate data corresponding to the axis information, the datum point information, and the U-shaped bolt installation distance parameter contained in the reference selection instruction are extracted, wherein the axis information is converted into a directional vector and position coordinate data in the coordinate system, the datum point information directly corresponds to a specific coordinate point in the coordinate system, and the U-shaped bolt installation distance parameter is converted into a linear distance coordinate relationship in the coordinate system in combination with the coordinates of the related datum points or axes; then the coordinate mapping operation is started, and the coordinate data of different types of datum information are associated and calculated, for example, the coordinates of a certain key datum point are taken as the reference origin, and the relative coordinate relationship of other datum points with respect to the origin is established through coordinate translation, rotation, and other mapping operations; for the axis information, the angle relationship and the spatial distance relationship between its directional vector and other datum points in the coordinate system are calculated; the coordinate relationship corresponding to the U-shaped bolt installation distance parameter is also established through mapping operation, and the coordinates of the related datum of the leaf spring steering bridge, such as the main piece center datum point and the vehicle frame limiting surface associated datum, are accurately corresponded to ensure that the parameter can accurately reflect the relative size of the actual installation position in the spatial coordinate system; the mapping result is automatically checked for rationality in the coordinate mapping process to ensure that the position correspondence relationship between the reference selection instructions meets the structure mechanics principle and the motion logic of the leaf spring steering bridge, and the spatial position conflict or associated fault is avoided; finally, the position correspondence relationship between the generated reference selection instructions is stored in the form of data linked list or associated matrix, which provides continuous and accurate spatial position basis for subsequent automatic creation of the motion mechanism skeleton model, definition of the kinematic pair, and calculation of the tire motion trajectory, and ensures that the motion mechanism can accurately restore the actual relative position and motion association of each component of the leaf spring steering bridge.

[0039] Step 204: Based on the position correspondence relationship, create a plurality of skeleton parts in the assembly design environment, and establish a mechanical connection relationship between the skeleton parts to constitute a motion mechanism skeleton model.

[0040] In this step, when the position correspondence relationship between the reference selection instructions is determined, the Figure 3The 31 button in the position correspondence relationship, enter the creation of the motion mechanism process; first, according to the function attribute and spatial coordinate association of each reference information in the position correspondence relationship, a plurality of skeleton parts are automatically created. These skeleton parts are not solid parts, but abstract expressions of the geometric features and motion cores of the key motion components of the leaf spring steering bridge. The creation process completely relies on the coordinate mapping logic determined in the position correspondence relationship. For example, the axis feature of the skeleton part is created according to the direction vector of the axis information and the position coordinates, the key node position of the skeleton part is determined according to the spatial coordinates of the reference point information, and the assembly reference interval between the skeleton parts is defined according to the coordinate relationship corresponding to the mounting distance parameter of the U-shaped bolt, so as to ensure that the geometric shape and spatial position of each skeleton part can accurately match the motion core demand of the actual component, and the relative position of each skeleton part strictly follows the association logic in the position correspondence relationship. Subsequently, based on the connection mode and motion logic of each component in the actual motion process of the leaf spring steering bridge, a mechanical connection relationship is established for the created skeleton parts. The establishment of this connection relationship also refers to the position correspondence relationship. For example, according to the position correspondence relationship between the center reference point of the leaf spring ear and the axis of the lug shaft, a connection structure simulating rotary motion is constructed between the corresponding skeleton parts. According to the coordinate association of the related reference points and the axis of the steering trapezoid, a linkage connection relationship between the skeleton parts of the steering trapezoid is established, so as to ensure that the connection relationship can truly reflect the actual motion association of each component of the leaf spring steering bridge. In this process, there is no need for manual setting of the motion pair parameters, but the definition of the connection relationship is automatically completed through the preset program logic, so as to ensure that the connection between the skeleton parts conforms to the structural mechanics principle and motion transmission law of the leaf spring steering bridge. Through the above steps of creating skeleton parts and establishing mechanical connection relationship, a motion mechanism skeleton model is finally formed. This model completely presents the core topological structure of the motion mechanism of the leaf spring steering bridge, and is automatically completed throughout the process, which not only avoids errors that may occur in manual operation, but also ensures that the model structure is highly matched with the actual motion demand of the leaf spring steering bridge, thereby providing a reliable basic framework for further applying driving constraints and generating standard degree of freedom motion mechanism.

[0041] Step 205: Traverse the skeleton parts to detect whether there is an independent motion component that has not been split.

[0042] In this step, when the motion mechanism skeleton model is initially constructed, the traversal detection of the skeleton parts is started, and all the created skeleton parts are scanned and analyzed one by one. The core detection target is to judge whether there is a part with independent motion characteristics in the plate spring steering bridge related components that has not been separated; this kind of independent motion part that has not been separated usually does not present in the form of an independent skeleton part due to the integration state at the initial model design. If it is left, it will cause confusion in the definition of the motion pair, deviation in the simulation of the motion trajectory, and then affect the accuracy of the tire envelope generation; in the traversal detection process combined with the structure and motion principle of the plate spring steering bridge, the correlation and motion characteristic identification of each skeleton part are checked according to the independent motion requirements of each part, for example, whether a certain skeleton part simultaneously carries multiple part characteristics that should be independently moved, or whether the motion logic of a certain part needs to rely on an independent skeleton part to be implemented, to identify whether there is an independent motion part that has not been separated. The whole detection process does not need manual intervention, which ensures that the independent motion part that may exist can be fully and without omission. It provides a basis for subsequent improvement of the motion mechanism skeleton model by creating a follow-up part, and guarantees that the motion mechanism can accurately restore the independent motion state of each part of the plate spring steering bridge.

[0043] Step 206: If there is an independent motion part that has not been separated, a follow-up part creation window is displayed on the user interaction interface, and the user's follow-up part creation instruction is received.

[0044] In this step, when the independent motion part that has not been separated is detected by traversing the skeleton parts, the response mechanism of the user interaction interface is triggered immediately to solve the motion simulation deviation problem that may be caused by such parts. At this time, the creation of associated elements interactive interface as shown in Figure 4 is automatically popped up in the current user interaction interface. Clicking button 42 in the main interface enters the creation of associated elements interface. For the independent motion part that has not been separated, a follow-up part needs to be created. Button 44 can be clicked to create a part in the assembly according to the selected features. The design of the follow-up part creation window is carried out around the convenience of user operation. The interface layout is consistent with the overall interaction logic of the software, which ensures that the user can quickly understand the operation target, and realizes the accurate processing of the independent motion part that has not been separated, and guarantees that each part in the motion mechanism skeleton model can participate in the subsequent simulation in the form of an independent motion unit, laying a foundation for the accuracy of the tire envelope generation.

[0045] In one embodiment, the code implementation of creating associated elements can be as follows:

[0046]

[0047]

[0048] Step 207: In response to the follow-up part creation instruction, display the preset assembly directory tree in the user interaction interface, so that the user selects the part corresponding to the independent moving part in the assembly directory tree.

[0049] In this step, when the follow-up part creation instruction issued by the user is received, the corresponding interaction response logic is immediately started, and the preset assembly directory tree is loaded and displayed in the 43 area of the Catia software, and the selection of the parts in the directory tree is associated with the corresponding skeleton model, and the corresponding name is displayed in the 45 area. Figure 4

[0050] In an embodiment, the Catia directory tree code implementation can be as follows:

[0051] TreeView1.Nodes.Clear

[0052] Set N=TreeView1.Nodes.Add(,,"A"&i,catia.ActiveDocument.Product.name,3,3)

[0053] Nodecount=1

[0054] Call TraverseProductTree(oProducts,"A"&i,0)

[0055] Set catObject(Nodecount)=catia.ActiveDocument.Product

[0056] TreeView1.Nodes(1).Expanded=True

[0057] Regarding the recursive function, the code implementation can be as follows:

[0058]

[0059]

[0060]

[0061] The method for synchronously selecting the CATIA software can be implemented by the following code:

[0062] Private Sub TreeView1_Click()

[0063] Dim catia As Object

[0064] ​Set catia = GetObject(,"CATIA.APPLICATION")

[0065] Set sel = catia.ActiveDocument.Selection

[0066] For i = 1 To Nodecount - 1

[0067] If Nodes(i).Checked = True Then

[0068] sel.Add catObject(i)

[0069] Else

[0070] For j = sel.Count To 1 Step -1

[0071] If sel.Item(j).Value Is catObject(i) Then

[0072] sel.Remove(j)

[0073] End If

[0074] Next j

[0075] End If

[0076] Next i

[0077] End Sub

[0078] Step 30: based on the preset constraint rules, the driving constraint is performed on the kinematic mechanism skeleton model to establish the kinematic pair corresponding to the skeleton parts in the kinematic mechanism skeleton model, and a standard degree of freedom kinematic mechanism is generated.

[0079] As an optional embodiment, based on the preset constraint rules, the driving constraint is performed on the kinematic mechanism skeleton model to establish the kinematic pair corresponding to the skeleton parts in the kinematic mechanism skeleton model, and a standard degree of freedom kinematic mechanism is generated. Specifically, it can include: step 301: calling the motion constraint type corresponding to the skeleton part from the preset constraint rule library.

[0080] In this step, once the initial structure of the motion mechanism skeleton model is completed, the motion constraint type corresponding to each skeleton part is matched and obtained from the preset constraint rule library. This preset constraint rule library is pre-built based on the structural characteristics, motion principles, and industry design specifications of the leaf spring steering axle. The library categorizes and stores the motion constraint types required by each key motion component of the leaf spring steering axle, such as constraint types that adapt to the rotation of the leaf spring around the lug, constraint types that match the steering trapezoidal linkage, and constraint types that conform to tire steering and bouncing. Each constraint type is clearly associated with the motion form and mechanical logic of a specific component, ensuring that it can accurately correspond to the actual motion scenario of the leaf spring steering axle.

[0081] Step 302: Based on the motion constraint type, call the CATIA kinematic pair creation API interface to establish kinematic pairs corresponding to the skeleton parts, and associate the kinematic pairs to obtain the initial motion mechanism.

[0082] In this step, after retrieving the motion constraint type corresponding to each skeleton part from the preset constraint rule library, the retrieved motion constraint type is converted into a parameter format recognizable by the CATIA motion pair creation API interface. Then, the CATIA motion pair creation API interface call instruction is triggered. For each skeleton part, based on its corresponding motion constraint type, a corresponding motion pair is automatically created in the CATIA assembly design environment. For example, if the motion constraint type of a skeleton part is a rotational constraint, the API interface is called to create a motion pair adapted to this rotational logic, connecting the skeleton part with other associated skeleton parts through rotational motion pairs. If it is a linkage constraint, a linkage-type motion pair that enables coordinated movement of multiple parts is created. After all the motion pairs corresponding to all skeleton parts are created, these independent motion pairs are further associated according to the motion transmission logic of the leaf spring steering axle. For example, the motion pairs of the leaf spring-related skeleton parts are associated with the motion pairs of the steering trapezoidal skeleton parts to ensure that the movement of the leaf spring can be transmitted to the steering system through the motion pairs, conforming to the actual motion transmission path.

[0083] In one embodiment, the code for creating a motion pair can be implemented using the following logic:

[0084] Set cTheMechanisms=catia.ActiveDocument.Product.GetTechnologicalObject("Mechanisms")

[0085] Set oNewMechanism=cTheMechanisms.Add()

[0086] oNewMechanism.name = "Leaf Spring Front Suspension Mechanism"

[0087] oNewMechanism.FixedPart = DMU01

[0088] Dim sRefName As String

[0089] sRefName = catia.ActiveDocument.Product.name & " / " & DMU04.name & " / !主销1"

[0090] Set oReferenceLine1 = catia.ActiveDocument.Product.CreateReferenceFromName(sRefName)

[0091] sRefName = catia.ActiveDocument.Product.name & " / " & DMU02.name & " / !主销1"

[0092] Set oReferenceLine2 = catia.ActiveDocument.Product.CreateReferenceFromName(sRefName)

[0093] sRefName = catia.ActiveDocument.Product.name & " / " & DMU04.name & " / !主销垂面1"

[0094] Set oReferencePlane1 = catia.ActiveDocument.Product.CreateReferenceFromName(sRefName)

[0095] sRefName = catia.ActiveDocument.Product.name & " / " & DMU02.name & " / !主销垂面1"

[0096] Set oReferencePlane2 = catia.ActiveDocument.Product.CreateReferenceFromName(sRefName)

[0097] Dim aVar(3)

[0098] Set aVar(0) = oReferenceLine1

[0099] Set aVar(1) = oReferenceLine2

[0100] Set aVar(2) = oReferencePlane1

[0101] Set aVar(3) = oReferencePlane2

[0102] Set oNewJoint = oNewMechanism.AddJoint ("CATKinRevoluteJoint", aVar)

[0103] Set oNewCommand2 = oNewMechanism.AddCommand ("CATKinAngleCmd", oNewJoint)

[0104] Step 303: Calculate the degrees of freedom of the initial motion mechanism using the degrees of freedom calculation tool of CATIA, and update the kinematic pairs in the initial motion mechanism until a motion mechanism with standard degrees of freedom is obtained.

[0105] In this step, after the initial motion mechanism containing the associated kinematic pairs is preliminarily constructed, the built-in degrees of freedom calculation tool of CATIA is called to analyze the degrees of freedom of the initial motion mechanism. The tool will automatically calculate the actual degrees of freedom value of the mechanism according to the number of each skeleton part, the type and number of kinematic pairs, and the association relationship between the kinematic pairs in the initial motion mechanism, and feed back the calculation result to the software system. At this time, the initial motion mechanism has the cases of under-constraint (degrees of freedom greater than the standard value, motion state uncertain) or over-constraint (degrees of freedom less than the standard value, motion exists card jam) due to kinematic pair configuration deviation, which cannot meet the requirements of the subsequent tire motion simulation on the stability of the mechanism. For the under-constraint case, the missing constraint type is analyzed according to the motion logic of the leaf spring steering axle and the pre-set constraint rule library, and the corresponding kinematic pair is automatically supplemented or the constraint parameters of the existing kinematic pair are optimized to reduce the redundant degrees of freedom of the mechanism. For the over-constraint case, the kinematic pair that causes constraint redundancy is investigated, and the redundant constraint is eliminated by adjusting the constraint range of the kinematic pair and removing unnecessary constraint association. After the kinematic pair is updated, the degrees of freedom of the updated motion mechanism are recalculated, and the above process is repeated, so as to cycle and iterate until a motion mechanism with degrees of freedom of 0 is obtained, which ensures that there is no motion uncertainty caused by under-constraint and no motion obstacle caused by over-constraint, and finally a standard degrees of freedom motion mechanism that meets the actual motion requirements of the leaf spring steering axle is obtained, providing a stable and reliable motion simulation basis for the subsequent precise simulation of tire motion trajectory and generation of tire envelope surface.

[0106] Step 40: based on the motion mechanism, the maximum steering angle and motion trajectory of the tire are calculated to generate the tire envelope.

[0107] As an optional embodiment, based on the motion mechanism, the maximum steering angle and motion trajectory of the tire are calculated to generate the tire envelope, which can specifically include: step 401: obtaining the motion pair parameters and constraint boundary conditions corresponding to the tire components in the motion mechanism.

[0108] In this step, when the motion mechanism is constructed, the button 52 on the main interface is clicked to enter the motion envelope creation interface, as shown in Figure 5 The 54 area is used to set the motion envelope body save path, the 55 area is the optional motion component list bar, and the 56 area is the selected production motion envelope component list; for the motion pair parameters corresponding to the tire components, the motion pairs directly associated with the tire in the motion mechanism are automatically identified through program logic, such as the motion pairs controlling the steering and bouncing of the tire, and the attribute data of these motion pairs in the CATIA environment is called. These parameters cover the type characteristics, motion direction definition and motion transmission association of the motion pairs, and these parameters are extracted and sorted from the motion mechanism data system of CATIA to form a structured motion pair parameter set, which ensures that the motion driving logic of the tire components can be accurately reflected; combined with the actual design specifications of the leaf spring steering bridge and the preset constraint rules of the motion mechanism, the boundary data limiting the motion range of the tire components is automatically captured. These constraint boundary conditions include not only the physical boundaries based on the structure limiting of the leaf spring steering bridge, but also the motion limit boundaries set based on the design requirements; the limit datum and the datum information related to the constraint in the pre-reference selection instruction in the motion mechanism are converted into specific constraint boundary parameters, which clearly define the range boundary that the tire components cannot exceed in the motion process, and ensure that the motion pair parameters and the constraint boundary conditions can accurately match the actual motion characteristics of the tire components, providing data support for subsequent simulation of the complete motion trajectory of the tire within the constraint range and generation of accurate tire motion envelope surface.

[0109] Step 402: based on the motion pair parameters and constraint boundary conditions, the motion process of the tire under the steering and bouncing working conditions is simulated to calculate the maximum steering angle of the tire under the corresponding working conditions.

[0110] In this step, first, according to the extracted tire kinematic pair parameters, the motion simulation logic matching the actual working condition is built. For the steering condition, according to the type of kinematic pair controlling the tire steering, the motion direction definition and the linkage relationship parameters, the motion transmission model of the tire with the steering system is constructed in the CATIA environment, ensuring that the simulated steering motion is consistent with the steering drive logic of the tire in the actual leaf spring steering axle. For the bounce condition, based on the tire bounce related kinematic pair parameters (such as the moving pair), the tire bounce motion rules in a specific direction are defined, so that the bounce process conforms to the motion trajectory and transmission characteristics set by the kinematic pair. During the motion simulation, the constraint boundary conditions are used as the motion restriction basis and applied to the simulated motion of the tire in real time. For example, in the steering condition simulation, physical boundary constraints such as the frame limiting surface, leaf spring limiting surface and preset motion limit boundary are introduced. When the tire steering angle reaches the critical state where interference with surrounding components or touching the limiting boundary is possible, the critical position corresponding to the steering angle value is captured. In the bounce condition simulation, the constraint boundary of the tire bounce is combined to analyze the influence of the relative position change of the tire and the associated components on the steering angle during the bounce process, avoiding the calculation deviation of the steering angle caused by the bounce.

[0111] Step 403: The motion process of the tire is divided into several continuous motion poses, and the spatial coordinate data of the tire in the motion pose is recorded to generate a tire motion trajectory data set.

[0112] In this step, first, according to the tire motion parameters and motion logic determined in the previous step, the complete motion process of the tire under the steering and bounce conditions is divided into several continuous and complete motion poses according to the fixed motion pose decomposition interval. These motion poses cover all key motion states of the tire from the initial position to the limit motion position, and the motion change between adjacent poses is uniform, ensuring that the actual motion path of the tire can be completely restored and the trajectory data is not discontinuous due to missing poses. For each decomposed motion pose, the three-dimensional spatial coordinate data of the tire key feature points in the CATIA model space is automatically collected by calling the coordinate acquisition interface of CATIA, such as the tire center, tire edge feature points, etc. These feature points have been preset as coordinate collection objects during the selection of the reference or the construction of the motion mechanism in the previous step. During the collection process, the working condition information corresponding to the current motion pose is associated in real time, and the working condition parameters are bound with the spatial coordinate data, ensuring that each set of coordinate data can accurately correspond to the spatial position of the tire under a specific motion pose.

[0113] Step 404: The maximum steering angle is associated with the tire motion trajectory data set to form a tire envelope.

[0114] In this step, first, the maximum steering angle data is attribute labeled to determine its corresponding working condition scene, such as the limit angle under the single steering working condition, the limit steering angle corresponding to different bounce positions, and the like, and the labeling information is matched with the working condition classification in the tire motion trajectory data set; subsequently, the tire motion trajectory data set is filtered and integrated with the maximum steering angle as the boundary condition, for the trajectory data related to the steering working condition, the spatial coordinate data of all continuous motion postures from the initial steering posture to the limit steering posture is extracted with the maximum steering angle corresponding motion posture as the limit node; for the trajectory data of the steering and bounce compound working condition, the trajectory coordinates corresponding to the maximum steering angle at each bounce position are filtered out, and the limit coordinates and the regular steering trajectory coordinates at the bounce position are integrated together to form a trajectory data set covering the complete motion range; through the geometric modeling function of CATIA, the discrete spatial coordinate data is converted into continuous geometric contours, these geometric contours are bounded by the limit trajectory corresponding to the maximum steering angle, and the spatial positions of the tire under all possible motion postures are wrapped to form a tire envelope that can completely reflect the motion space range of the tire, and the consistency of the data is verified in the association process to ensure that the limit trajectory corresponding to the maximum steering angle is accurately integrated into the overall envelope contour, avoid the envelope range missing or exceeding the actual motion boundary due to data association deviation, and finally generate a precise tire envelope meeting the design checking requirements of the leaf spring steering axle.

[0115] Step 405: output the tire envelope in stl file format, and parse the spatial geometric data in the stl file to generate multi-surface features consistent with the geometric shape of the stl file.

[0116] In this step, when the construction of the tire envelope is completed, click the 53 button in Figure 5 to generate the envelope position of the moving part and save it as a.stl format file. The stl format is a commonly used three-dimensional model data format that can completely record the spatial geometric contour information of the tire envelope, providing a basic data carrier for subsequent geometric data parsing; click the 57 button in Figure 5 to convert the generated.stl file into the editable surface feature part on the right side of Figure 6 ;

[0117] In one embodiment, generating a motion envelope and keeping it in STL format can be as follows:

[0118]

[0119]

[0120] The above code directly creates a CATIA temporary macro command in the program and runs, avoiding the problem of CATIA API interface call out of office by VB6.

[0121] Step 406: integrity check is performed on the multi-surface feature, and if there are gaps and / or overlaps and / or geometric defects in the multi-surface feature, the multi-surface feature with defects is repaired to obtain a repaired multi-surface feature.

[0122] In this step, after the multi-surface feature is generated, the generated multi-surface feature is comprehensively detected according to the geometric design specifications and the continuity requirements of the surface of the leaf spring steering axle tire envelope. The detection focuses on three aspects: first, check whether there is a gap between the surfaces, that is, determine whether the edges of adjacent surfaces completely fit to avoid subsequent envelope range calculation deviation caused by the gap; second, investigate whether there is an overlap between the surfaces, identify whether different surfaces have an area overlap in space, and prevent the overlap from affecting the accuracy of the geometric model; third, identify whether there are geometric defects such as surface distortion, irregular boundary, and curvature mutation that affect the quality of the surface. The entire verification process is completed by automatically comparing the topological relationship, boundary coordinates, and curvature parameters of the surface through software without human intervention, ensuring the objectivity and comprehensiveness of the detection results. If it is found after verification that the multi-surface feature has gaps, overlaps, or geometric defects, the different types of defects are repaired: for surface gaps, according to the boundary geometric features of adjacent surfaces, the gap area is filled by surface extension, boundary fitting, and other algorithms to achieve smooth connection between adjacent surfaces; for surface overlap, the software identifies the spatial coordinate range of the overlapping area, deletes the redundant overlapping part according to the original logic of surface generation, and retains the surface area that conforms to the actual shape of the tire envelope; for geometric defects, the analyzed stl file spatial geometric data is retrieved again, and the original geometric contour is used as a reference to re-fit or locally reconstruct the defective surface to correct curvature mutation, boundary anomaly, and other problems; after the repair is completed, the integrity check is started again to confirm that the defects have been completely eliminated, and finally the repaired multi-surface feature with complete geometric shape and precision is obtained.

[0123] Step 407: convert the repaired multi-surface feature into an editable part file, and provide a query path of the editable part file for user calling and editing.

[0124] In this step, after the integrity check and repair of the multi-surface feature is completed, the repaired multi-surface feature is converted and restructured according to the format specification of the CATIA editable part. During the conversion process, all geometric information of the multi-surface feature is preserved, and standard editable properties are assigned to the part file, supporting user operations such as trimming, stitching, thickening, or adding new geometric features, ensuring that the converted part file fully supports CATIA part editing functions, breaking the limitations of STL files or simple multi-surface features that are difficult to edit; subsequently, the storage path of the part file is clearly displayed in the user interaction interface, and the path information is usually associated with the motion envelope body save path set in the early stage, ensuring that the user can quickly locate in the familiar file directory system, making it easy for users to quickly find the target file through keyword search in the future; through the above conversion and path providing steps, users can directly call the editable part file for subsequent design work of the leaf spring steering bridge, and can also perform secondary editing of the part file based on actual needs, ensuring the reusability and expandability of the tire envelope model, and further improving the efficiency and flexibility of the entire leaf spring steering bridge design process.

[0125] The above is the method embodiment of the present application. Based on the same inventive concept, the present application also provides a Catia-based leaf spring steering bridge tire envelope generation device. The device comprises: a reference selection module, which is used to receive user input reference selection instructions based on a pre-set user interaction interface; wherein the reference selection instructions include axis information, reference point information, and U-shaped bolt installation distance parameters of the leaf spring steering bridge; a motion mechanism skeleton creation module, which is used to input the reference selection instructions into CATIA to create a skeleton part corresponding to the reference selection instructions, and associate the skeleton part to form a motion mechanism skeleton model; a motion mechanism creation module, which is used to drive and constrain the motion mechanism skeleton model based on pre-set constraint rules to establish the motion pairs of the skeleton parts in the motion mechanism skeleton model, and generate a standard degree of freedom motion mechanism; a motion envelope generation module, which is used to calculate the maximum steering angle and motion trajectory of the tire based on the motion mechanism to generate a tire envelope.

Claims

1. A method for generating a Catia-based leaf spring steering axle tire envelope, the method comprising: The method comprises: receiving a user inputted reference selection instruction based on a preset user interaction interface; wherein the reference selection instruction comprises axis information of a leaf spring steering bridge, reference point information and U-shaped bolt installation distance parameters; inputting the reference selection instruction into CATIA to create a skeleton part corresponding to the reference selection instruction, and associating the skeleton part to constitute a kinematic mechanism skeleton model; driving and constraining the kinematic mechanism skeleton model based on a preset constraint rule to establish kinematic pairs corresponding to the skeleton parts in the kinematic mechanism skeleton model, and generating a standard degree of freedom kinematic mechanism; based on the kinematic mechanism, calculating the maximum steering angle and motion trajectory of the tire to generate a tire envelope.

2. A method for generating a tire envelope of a leaf spring steering axle based on Catia as claimed in claim 1, wherein, Receiving a user inputted reference selection instruction, specifically comprising: based on the preset reference geometric element type selection field in the CATIA user interaction interface, receiving user selected axis information, reference point information and U-shaped bolt installation distance parameters; verifying whether the axis information meets the rotation space requirements of the tire, verifying whether the reference point information constitutes a complete leaf spring kinematic chain topology structure, and verifying whether the U-shaped bolt installation distance parameters are within a preset feasible range; outputting the verified axis information, reference point information and U-shaped bolt installation distance parameters to obtain the reference selection instruction.

3. The Catia based leaf spring axle tire envelope generation method of claim 1, wherein, Before inputting the reference selection instruction into CATIA, the method further comprises: identifying the environment type of the CATIA; wherein the environment type comprises a part design environment and an assembly design environment; when the environment type is the part design environment, converting the part design environment to the assembly design environment.

4. The Catia based leaf spring axle tire envelope generation method of claim 3, wherein, Inputting the reference selection instruction into CATIA to create a skeleton part corresponding to the reference selection instruction, and associating the skeleton part to constitute a kinematic mechanism skeleton model, specifically comprising: based on the reference selection instruction, using coordinate mapping to generate a position correspondence relationship between the reference selection instructions; based on the position correspondence relationship, creating a plurality of skeleton parts in the assembly design environment and establishing mechanical connection relationships between the plurality of skeleton parts to constitute the kinematic mechanism skeleton model.

5. A method of generating a tire envelope for a leaf spring steering axle as claimed in claim 1, wherein, Before generating a standard degree of freedom kinematic mechanism, the method further comprises: traversing the skeleton parts to detect whether there is an undivided independent motion component; if there is the undivided independent motion component, displaying a follow-up part creation window in the user interaction interface and receiving a follow-up part creation instruction of the user; in response to the follow-up part creation instruction, displaying a preset assembly directory tree in the user interaction interface to enable the user to select a part corresponding to the undivided independent motion component in the assembly directory tree.

6. A method of generating a tire envelope for a leaf spring steering axle of a vehicle based on Catia as claimed in claim 1, wherein, Driving and constraining the kinematic mechanism skeleton model based on a preset constraint rule to establish kinematic pairs corresponding to the skeleton parts in the kinematic mechanism skeleton model, and generating a standard degree of freedom kinematic mechanism, specifically comprising: retrieve a motion constraint type corresponding to the skeleton part from the preset constraint rule library; wherein the motion constraint type comprises a rotation constraint, a movement constraint and a fixed constraint; based on the motion constraint type, calling a motion pair creation API interface of CATIA to establish a motion pair corresponding to the skeleton part, and associating the motion pair to obtain an initial motion mechanism; using a degree of freedom calculation tool of CATIA, calculating the degree of freedom of the initial motion mechanism, and updating the motion pair in the initial motion mechanism until a motion mechanism with the standard degree of freedom is obtained.

7. A method of generating a tire envelope for a leaf spring steering axle of a vehicle based on Catia as claimed in claim 1, wherein, based on the motion mechanism, calculating the maximum steering angle and the motion trajectory of the tire to generate a tire envelope, specifically comprising: obtaining the motion pair parameters and the constraint boundary conditions corresponding to the tire component in the motion mechanism; based on the motion pair parameters and the constraint boundary conditions, simulating the motion process of the tire under the steering and bouncing working conditions to calculate the maximum steering angle of the tire under the corresponding working conditions; decomposing the motion process of the tire into a plurality of continuous motion postures, and recording the spatial coordinate data of the tire in the motion postures to generate a tire motion trajectory data set; associating the maximum steering angle with the tire motion trajectory data set to constitute the tire envelope.

8. A method of generating a tire envelope for a leaf spring steering axle of a vehicle based on Catia as claimed in claim 1, wherein, After generating the tire envelope, the method further comprises: outputting the tire envelope in an stl file format, and parsing the spatial geometric data in the stl file to generate a multi-surface feature consistent with the geometric shape of the stl file; performing integrity verification on the multi-surface feature, and if the multi-surface feature has gaps and / or overlaps and / or geometric defects, repairing the multi-surface feature with defects to obtain a repaired multi-surface feature; converting the repaired multi-surface feature into an editable part file, and providing a query path of the editable part file for the user to call and edit.

9. A Catia based leaf spring steering axle tire envelope generation device, characterized by, The device comprises: a reference selection module, which is configured to receive a reference selection instruction input by a user based on a preset user interaction interface; wherein the reference selection instruction comprises axis information, reference point information and U-shaped bolt installation distance parameters of a leaf spring steering bridge; a motion mechanism skeleton creation module, which is configured to input the reference selection instruction into CATIA to create a skeleton part corresponding to the reference selection instruction, and associate the skeleton part to constitute a motion mechanism skeleton model; a motion mechanism creation module, which is configured to drive and constrain the motion mechanism skeleton model based on preset constraint rules to establish a motion pair corresponding to the skeleton part in the motion mechanism skeleton model, and generate a motion mechanism with a standard degree of freedom; a motion envelope generation module, which is configured to calculate the maximum steering angle and the motion trajectory of the tire based on the motion mechanism to generate a tire envelope.

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