Wiring harness cable layout and outer diameter simulation calculation method based on discrete elements

Abstract

The invention belongs to the field of wiring harness and cable layout and simulation, and particularly relates to a wiring harness and cable layout and outer diameter simulation calculation method based on discrete elements, which comprises the following steps of: 1) obtaining all cable serial numbers and diameter information through an input mode of a data interface or a text editor, carrying out data validity test, importing into a calculation system, and carrying out calculation; the import state is displayed, so that checking is facilitated; 2) according to the number and diameter information of all cables, simulating the random position state of the cables before binding the wire harness through a random position algorithm; and 3) based on the position state of the cable before the wire harness is bound, setting a calculation assumption condition, simulating the movement of the cable along with the binding and tightening process of the wire harness, and obtaining the final coordinate values of all the cables, a cable layout diagram and the outer diameter value of the wire harness. The invention provides different engineering solutions close to actual engineering conditions, and is suitable for all cable combination conditions possibly applied in actual engineering, including combinations of any number and any specification and size.

Description

Technical Field

[0001] The invention belongs to the field of wiring harness cable layout and simulation, in particular to a wiring harness cable layout and outer diameter simulation calculation method based on discrete elements. Background Art

[0002] In the aviation, automotive and other engineering fields, a model has hundreds or thousands of wiring harness segments. The cable layout and outer diameter in the wiring harness segments need to be repeatedly calculated at different development stages and different levels of maturity to support the design and analysis of wiring harness space models (wiring harness bending radius, structural perforations, spatial isolation distance, etc.), selection of wiring harness accessories and installation materials (wiring harness sleeves, connector tail clips, support clamps, etc.), and optimization of wiring harness performance analysis (current-carrying temperature rise, electromagnetic interference, arc damage, etc.).

[0003] There are three main methods for calculating the outer diameter of wire harnesses currently used in the industry, among which method 2 is widely used:

[0004] 1. Diameter coefficient method: (When the diameters of all cables are the same, i.e., d, it can be simplified to D=K×d), where K is the outer diameter calculation coefficient, which is obtained from the harness outer diameter calculation coefficient table.

[0005] 2. Area superposition method: Generally K (square area superposition), there are also projects where K will take different empirical values ​​such as 1 (circle area superposition, minimum K value), 1.154, 1.2, 1.286 (which can be understood as gradually increasing the gap factor, where 1.286 is the default value of CHS electrical design software). For example, the patent name is: A method for estimating the outer diameter of a wire harness, and the publication number is: CN110879911. In the invention patent, the actual value of K is 1; for example, the patent name is: A method, system, medium and equipment for calculating the outer diameter of an automotive wire harness, and the publication number is: CN113836641. In the invention patent, the actual value range of K is 1.225 to 1.265; for example, the paper "Research on Wire Harness Diameter Estimation Method Based on Gap Compensation" (Trainer 2020.NO.1) is essentially a typical K value optimization calculation study for a certain cable combination.

[0006] 3. Arrangement and filling method: All cables in the harness are initially arranged in a certain order (such as diameter size), and then gradually arranged in layers or different circles from the inside to the outside to solve the minimum envelope circle. Related research includes patents such as: Minimum diameter design method for multi-strand wire harness sheath, publication number: CN102184275 invention patent; and patents such as: A method for simulating the outer diameter of an aircraft harness and estimating the outer diameter of a trunk harness, publication number: CN113962024 invention patent.

[0007] However, there are many defects in the above three existing methods. For example, the paper "Comparative Analysis of Calculation Methods for Wiring Harness Diameter of Civil Aircraft" (Military and Civilian Dual-Use Technology and Products 20179 (2)) analyzes and compares some of the values ​​in the diameter coefficient method (hereinafter referred to as method 1) and the area superposition method (hereinafter referred to as method 2) in the above background technology. The error of method 1 is relatively large, and method 2 is recommended. Although method 2 is the most widely used, its ideal K value should be different under different cable combinations. This is why there are different K values ​​in different project backgrounds. It is difficult to select a universal K value that is suitable for a wide variety of wiring harnesses. In some combinations (such as a small number of cables, large differences in cable diameters, etc.), the calculation error of the wiring harness diameter is large, and method 2 can only roughly calculate the wiring harness diameter and cannot simultaneously obtain the corresponding cable layout.

[0008] Although the arrangement and filling method (hereinafter referred to as method 3) can obtain the cable layout and the corresponding harness outer diameter at the same time, it has certain manual operations and restrictions on the cable layout sorting (such as arranging from large to small, etc.), and it is not easy to calculate under certain cable combinations (such as large differences in cable diameters, etc.). At present, it is basically not used in the industry.

[0009] In actual projects, it can be considered that the combination of cables in the wire harness is infinite, the binding layout is completely random, and the outer diameter of the wire harness will be different under different layout conditions. There will also be differences in different directions when measuring the outer diameter of the wire harness. Because the cable insulation and sheath materials have a certain elasticity and can be compressed, the outer diameter of the wire harness will also change with the tightness of the binding. Therefore, there is no single optimal solution for the outer diameter of the wire harness and the cable layout in actual projects. What should be explored is an engineering solution that can adapt to the above multiple situations.

[0010] Therefore, according to the above-mentioned defects of the prior art, establishing a fast and accurate wiring harness cable layout and wiring harness outer diameter simulation calculation method has important engineering application value. Summary of the invention

[0011] The purpose of the present invention is to provide a computer simulation method based on a simplified discrete element method (DEM), which can import all the cable diameter information of the harness, simulate the initial random placement of the cables in the actual harness cable binding process, the harness binding contraction and the movement of the cables, and obtain different cable layouts and corresponding harness outer diameters through multiple iterative calculations. The entire process and results can be displayed graphically in real time. In addition, auxiliary functions such as allowing the display ratio to be set, allowing the position of any cable to be manually adjusted by dragging the graphics at the initial position and during the calculation process, and allowing the elastic overlap value between cables to be set are provided to improve the convenience, flexibility and accuracy of the operation process.

[0012] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a wiring harness cable layout and outer diameter simulation calculation method based on discrete elements, comprising the following steps:

[0013] 1) Obtain all cable numbers and diameter information through the data interface or text editor input method, perform data validity check, import into the calculation system, and display the import status for easy inspection and verification;

[0014] 2) Based on the number and diameter information of all cables, the random position algorithm is used to simulate the random position state of the cables before the harness is tied;

[0015] 3) Based on the cable position status before harness binding and setting calculation assumptions, simulate the movement of cables during the harness binding and tightening process to obtain the final coordinate values ​​of all cables, cable layout diagram and harness outer diameter value.

[0016] The step 2) comprises the following steps:

[0017] 2-1) Set the initial maximum outer diameter of the harness and display it using auxiliary operation A1;

[0018] 2-2) Traverse all cables to be randomly placed, and determine the value interval [X] of the x-coordinate of the cable i to be placed according to the outer diameter of the harness and the cable diameter, which ensures that the cable position is within the outer diameter envelope of the harness;

[0019] 2-3) Randomly generate the x coordinate of the cable i to be placed according to the value interval [X] of the x coordinate of the cable i, and initialize the value interval [Y] of the y coordinate of the cable i, which ensures that the cable position is within the outer diameter envelope of the harness;

[0020] 2-4) Traverse all the cables that have been placed, and determine the coordinate interval [y] where interference will occur between the cable i to be placed and the cable j that has been placed;

[0021] 2-5) traverse the y-coordinate value interval [Y] of the cable i to be placed, determine the relationship between the nth segment value [Yn] of the interval [Y] and [y], and adjust [Yn] so that it does not contain [y];

[0022] 2-6) If the y-coordinate value interval [Y] of the cable i to be placed is an empty set, return to step 2-3); otherwise, randomly generate the y-coordinate of the cable i within the y-coordinate value interval [Y], and combine it with the x-coordinate determined in step 2-3) to obtain the placement coordinates of the cable i to be placed, and place the cable according to the coordinates; if the calculation exceeds the set maximum number of cycles, [Y] is always an empty set, return to step 2-1) to increase the initial outer diameter of the harness;

[0023] 2-7) After the cable position is randomly initialized, the cable position is allowed to be manually adjusted through auxiliary operation A2 to simulate the human adjustment that may exist in actual engineering.

[0024] The auxiliary operation A1 is a method for adjusting the display ratio of the coordinate axis, which determines the interval size of the x and y coordinate axes by adjusting the screen resolution and the coordinate axis ratio, and then adjusts the initial outer diameter of the wire harness;

[0025] The auxiliary operation A2 is to manually adjust the cable position after the random initial position and after the outer diameter shrinkage calculation of the harness. The adjusted position must meet the following conditions:

[0026] Within the outer diameter envelope of the harness; and the contact overlap with the outer diameter envelope of the harness is within the maximum allowable value; at the same time, the contact overlap with all other cable circles is within the maximum allowable value.

[0027] In the steps 2-2) to 2-4), the value range [X] of the x-direction coordinate of the cable i to be placed is: [-(Rr i ),(Rr i )];

[0028] According to the outer diameter of the harness and the x-coordinate of the cable i to be placed, the cable y-coordinate value range [Y] is initialized as:

[0029]

[0030] When | r i -r j |>|x i -x j |, the y value interval [y] where the cable to be placed i interferes with the placed cable j is:

[0031]

[0032] Where R is the outer diameter of the harness, r i 、x i ,y i is the diameter and coordinates of the cable to be placed, r j 、x j ,y j are the diameter and coordinates of the placed cables.

[0033] The steps 2-5) are specifically:

[0034] If the relationship between interval [y] and the nth segment value [Yn] of interval [Y] is: there is partial overlap, then the overlapping part is cancelled;

[0035] If the relationship between the interval [y] and the nth value [Yn] of the interval [Y] is: Then the adjustment interval [Yn] is two discontinuous intervals;

[0036] If the relationship between the interval [y] and the nth value [Yn] of the interval [Y] is: Then cancel the interval [Yn].

[0037] The calculation assumptions include:

[0038] a. All forces on the cable only consider the elastic extrusion force caused by contact overlap, and do not consider the friction between boundaries;

[0039] b. Each time the harness is retracted, the cable moves to a new position due to external force and stops;

[0040] c. The force between cables is a passive conductive force. Since its value is proportional to the overlap between cables, the contact force between cables is set equal to the overlap value.

[0041] d. The contact force between the cable and the harness is the main driving force of the movement process. The specific value needs to be calculated in combination with the force between the cables to ensure the correct movement of the cables;

[0042] e. The position movement vector of the cable in each calculation cycle is equal to its resultant force vector.

[0043] The step 3) comprises the following steps:

[0044] 3-1) The outer diameter envelope of the harness is gradually contracted according to the set step length. Each contraction is a main calculation cycle. To achieve process visualization and calculation accuracy, the contraction step length is one display pixel unit; and the auxiliary operation A3 is used to set the maximum allowable overlap value of the cable;

[0045] 3-2) Calculate the stress between all cables and on the boundaries of the harness after the outer diameter envelope of the harness shrinks or the cable moves for one cycle;

[0046] 3-3) Determine the calculation strategy based on the cable stress conditions and boundary constraints:

[0047] If all cables are not stressed, or the movement calculation cycle exceeds the maximum setting value, return to step 3-1), and the outer diameter of the harness continues to shrink;

[0048] If the cable is under stress, the contact overlap between the cable and the harness is within the maximum allowable value, and the movement calculation cycle is within the maximum set value, go to step 3-4) and move the cable to a new position;

[0049] If the contact and overlap between the cable and the harness reaches the maximum allowable value, proceed to step 3-5) and the outer diameter of the harness is shrunk;

[0050] 3-4) moving the cables to new positions according to the stress conditions of all cables, and returning to step S3-2) to recalculate the stress conditions of all cables;

[0051] 3-5) When the contact and overlap between the cable and the harness reaches the maximum allowable value, the harness outer diameter is shrunk, and the harness outer diameter value, all cable coordinate values, and cable layout diagram are obtained; if you are not satisfied with the calculation results, adjust the cable position by using auxiliary operation A2, and then return to step 3-1) for multiple iterative calculations.

[0052] The auxiliary operation A3 is specifically:

[0053] Set the maximum allowable cable contact overlap value. This value is defined as the maximum number of pixels allowed for the cable circle to overlap with other cable circles and the outer diameter circle of the harness, and is understood as the cable elasticity value to prevent cable movement from getting stuck.

[0054] The step 3-2) is specifically:

[0055] (1) Obtaining the contact force between cables:

[0056] The resultant force vector on each cable is the superposition of the force vectors of all cables that are in contact and overlap with other cables, that is:

[0057] F a线缆间合力 =F ab +F ac +...F an

[0058] Among them, F ab =F ba , F ac =F ca , F an =F na , n is the number of the last cable;

[0059] (2) Obtain the contact force between the cable and the harness:

[0060] If the cable overlaps with the outer diameter of the harness, the force direction points to the center of the harness, and the contact force value is the overlap value multiplied by the adjustment coefficient k to ensure that the cable moves correctly to the envelope track that contacts and does not overlap with the harness; the k value is transformed into a quadratic equation by the following equation, that is:

[0061] ||F a线缆间合力 +k×F a线束 +P a ||2=Rr a

[0062] Where R is the outer diameter of the harness, P a 、r a are the current coordinate matrix and diameter of cable a respectively; the small value solution of the above formula is the adjacent position; the large value solution is the position on the other side symmetrical to the center of the harness;

[0063] (3) Obtain the resultant force on the cable:

[0064] The resultant force on the cable is the sum of the contact force vector between the cables and the contact force vector of the harness, that is:

[0065] F a合力 =F a线缆间合力 +F a线束 .

[0066] In step 3-4), the moving cable to a new location is:

[0067] P′ a =P a +F a合力

[0068] Among them, P a , P′ a are the coordinates of the cable before and after movement, F a合力 is the vector of the resultant force acting on the cable.

[0069] The present invention has the following beneficial effects and advantages:

[0070] 1. Universal applicability: The present invention is applicable to all cable combinations that may be used in actual projects, including combinations of any quantity and any size.

[0071] 2. Accuracy and completeness: The present invention provides different engineering solutions for the outer diameter of the wire harness and the cable layout that are close to the actual engineering conditions by simulating the actual wire harness binding process. The solution set includes complete information such as the outer diameter of the wire harness, the position coordinates of all cables, and the cable layout diagram.

[0072] 3. Operational flexibility: The present invention provides auxiliary functions such as manually adjusting the cable position, setting the maximum allowable cable overlap value, and adjusting the coordinate axis display ratio, which can assist the algorithm in obtaining ideal calculation results.

[0073] 4. Quick visibility: The present invention implements the algorithm process through computer program, a single calculation simulation process is controlled within 1 minute, and the entire calculation process and results are visualized. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 Flow chart of the method for calculating the layout and outer diameter simulation of the wiring harness cable based on discrete elements of the present invention;

[0075] Figure 2 Flowchart of the cable random position algorithm of the present invention;

[0076] Figure 3 An example diagram of the results of two random position calculations for the same cable combination according to the present invention;

[0077] Figure 4Schematic diagram of the force conditions between cables in the present invention (typical example of the force conditions between cables);

[0078] Figure 5 Schematic diagram of the force conditions between the cable and the harness in the present invention (a typical example of the force conditions between the cable and the harness);

[0079] Figure 6 A schematic diagram of the coordinate axis ratio of the auxiliary method A1 of the present invention;

[0080] Figure 7 An exemplary diagram of the effects of the embodiments of the present invention. DETAILED DESCRIPTION

[0081] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0082] This solution adopts a computer simulation method based on the simplified discrete element method (DEM) (Note: The discrete element method is a numerical simulation method for predicting the movement characteristics of granular media, which is widely used in fields such as geotechnical engineering). It can import all the cable diameter information of the harness, simulate the initial random placement of the cables during the actual harness cable binding process, the harness binding contraction and the movement of the cables, and obtain different cable layouts and corresponding harness outer diameters through multiple iterative calculations. The entire process and results can be displayed graphically in real time. In addition, it provides auxiliary functions such as allowing the display ratio to be set, allowing the position of any cable to be manually adjusted by dragging the graphics at the initial position and during the calculation process, and allowing the elastic overlap value between cables to be set, so as to improve the convenience, flexibility and accuracy of the operation process.

[0083] The specific process steps are as follows Figure 1 As shown, it is a flow chart of the method for calculating the layout and outer diameter simulation of the wiring harness cable based on discrete elements of the present invention. The specific process steps are described as follows:

[0084] Step S1: Check and import harness cable data. Obtain all cable numbers and diameter information through a data interface or text editor, perform data validity check, import into the calculation system, and display the import status for easy inspection and verification.

[0085] Step S2: Simulate the random position state of the cables before the harness is tied. Set the initial maximum outer diameter of the harness, and use the random position algorithm to randomly generate and place all imported cables within the outer diameter envelope of the harness, and display them. For details of the process steps, see Figure 2 , where the coordinate value interval of the cable i to be placed is calculated as follows:

[0086] The range of x values ​​is: [-(Rr i ),(Rr i )];

[0087] The initial y value range is:

[0088] When | r i -r j |>|x i -x j |, the y value range where the cable to be placed i interferes with the placed cable j is:

[0089] (Note: The above R is the outer diameter of the wire harness, r i 、x i ,y i is the diameter and coordinates of the cable to be placed, r j 、x j ,y j is the diameter and coordinates of the placed cable)

[0090] To avoid the lack of space for subsequent cables due to insufficient wiring harness envelope space, you can try to reasonably set the initial maximum outer diameter of the harness (i.e. adjust the display ratio through auxiliary step A1). For example, in aviation applications, the initial outer diameter of the harness can be set in the range of 10 to 100 mm depending on the size of the harness. For an example of the implementation effect of this step, see Figure 3 .

[0091] Step S3: Simulate the movement of the cable during the tightening process of the harness. To simplify the calculation, the following important assumptions are made. By assuming that the main influencing physical factors are focused on, the influence of secondary factors such as cable mass, friction, movement speed, and movement time are ignored and simplified, and the calculation assumptions are set, specifically:

[0092] 1) All forces on the cable only consider the elastic extrusion force caused by contact overlap, and do not consider the friction between boundaries;

[0093] 2) After each cable harness is retracted, the cable moves to a new position due to external force and then stops;

[0094] 3) The force between cables is a passive conductive force. Since its value is proportional to the overlap between cables, the contact force between cables is set equal to the overlap value.

[0095] 4) The contact force between the cable and the harness is the main driving force of the movement process. The specific value needs to be calculated based on the force conditions between the cables to ensure that the cables move correctly.

[0096] 5) The position movement vector of the cable in each calculation cycle is equal to its resultant force vector.

[0097] Step S3-1: Simulate the process of gradually tightening and shrinking the harness. The outer diameter envelope of the harness is gradually shrunk according to the set step length. Each contraction is a main calculation cycle. To achieve process visualization and calculation accuracy, the contraction step length can be taken as a display pixel unit.

[0098] Step S3-2: Calculate the stress between all cables and on the boundaries of the harness after the harness envelope shrinks or the cables move for one cycle.

[0099] (1) Contact force between cables: The resultant force vector on each cable is the superposition of the force vectors of all cables that are in contact and overlap with other cables. For a typical example of force conditions, see Figure 4 ,Right now:

[0100] F a线缆间合力 =F ab +F ac +...; and there is F ab =F ba , F ac =F ca ,….

[0101] (2) Contact force between cable and harness: If the cable overlaps with the outer diameter envelope of the harness, the force direction points to the center of the harness. The contact force value is the overlap value multiplied by the adjustment coefficient k to ensure that the cable moves correctly to the envelope track that contacts (does not overlap) the harness. The k value can be transformed into a quadratic equation by the following equation (the small value solution should be taken, which is the adjacent position; the large value solution is the position on the other side symmetrical to the center of the harness):

[0102] ||F a线缆间合力 +k×F a线束 +P a ||2=Rr a , where R is the outer diameter of the harness, P a 、r a are the current coordinate matrix and diameter of cable a respectively. Typical examples of stress conditions are as follows: Figure 5 shown.

[0103] (3) The resultant force on the cable is the sum of the contact force vector between the cables and the contact force vector of the harness, that is:

[0104] F a合力 =F a线缆间合力 +F a线束

[0105] Step S3-3: Determine the subsequent steps according to the cable stress condition, including:

[0106] 3-3-1) All cables are not stressed, or the movement calculation cycle exceeds the maximum setting value, return to step S-1, and the outer diameter of the harness continues to shrink;

[0107] 3-3-1) If the cable is under stress, the contact and overlap between the cable and the harness is within the maximum allowable value, and the movement calculation cycle is within the maximum set value, go to step S-4 and move the cable to a new position;

[0108] 3-3-1) If the contact and overlap between the cable and the harness reaches the maximum allowable value, the process goes to step S3-5 and the outer diameter of the harness is shrunk.

[0109] Step S3-4: Move the cables to new positions according to the stress conditions of all cables, and then return to step S3-2 to re-check and calculate the stress conditions of all cables. The calculation of the new position of the cables is:

[0110] P′ a =P a +F a合力

[0111] Among them, P a , P′ a They are the coordinates before and after the cable moves.

[0112] Step S3-5: When the overlap between the cable and the harness reaches the maximum allowable value, the harness outer diameter shrinks, and the harness outer diameter value, all cable coordinate values, and cable layout diagram can be read. If you are not satisfied with the calculation result, you can manually adjust the cable circle position through auxiliary step A2, and then return to step S3-1 for multiple iterative calculations.

[0113] Auxiliary step A1: Provide the function of adjusting the display scale of the coordinate axis to optimize the calculation accuracy and result display. The origin of the coordinate axis is located at the center of the screen, and the unit of the coordinate axis scale is pixel / mm. Figure 6 As shown in the example, the screen resolution is 1920*1080, the coordinate axis scale is 20 pixels / mm, the display coordinate axis x-axis range is approximately (-48mm, 48mm), and the y-axis range is approximately (-27mm, 27mm).

[0114] Auxiliary step A2: Provides a manual cable position adjustment function, which can manually adjust the cable position after the random initial position and the calculation of the harness outer diameter shrinkage. The adjusted position must meet the following conditions:

[0115] 1) Within the outer diameter envelope of the harness;

[0116] 2) The contact overlap with the outer diameter envelope of the harness is within the maximum allowable value;

[0117] 3) The contact overlap with all other cable circles is within the maximum allowable value.

[0118] Auxiliary step A3: Provides the function of setting the maximum allowable value of cable contact overlap (which can be understood as cable elasticity). Cables actually have a certain elasticity and can be deformed and compressed. If they are purely rigid objects, it will cause movement obstruction. To solve this problem, the "maximum allowable overlap value" parameter is introduced in the calculation, which is defined as the maximum number of pixels allowed to overlap between the cable circle and other cable circles and the outer diameter circle of the harness. If the coordinate axis scale is 20 pixels / mm, the maximum allowable overlap is 5 pixels, which can be converted to the actual maximum allowable overlap of 0.25mm. The larger the allowable overlap value, the more conducive it is to the movement between cables and the shrinkage calculation of the harness, but excessive overlap may deviate from the actual engineering situation and cause distorted results. It is recommended to combine the manual adjustment of the cable position function for calculation.

[0119] The final implementation effect of this plan is shown in Figure 7 ,For the harness of 52 cable combinations, the two random calculation layout results ,corresponding to the harness outer diameters of 35.7mm and 35.5mm respectively.

[0120] In summary, the key technical points of the present invention are:

[0121] 1. Initialize the cable position through an efficient random position algorithm to simulate the random position state of the cables before wiring harness binding.

[0122] 2. By reasonably setting the discrete element method application assumptions, ignoring and simplifying minor physical influencing factors, calculating and simulating the cable force and movement, and simulating the wire harness outer diameter envelope shrinkage and cable movement process during the wire harness binding process.

[0123] 3. Through the computer, the input data is checked, the simulation process is calculated, and the motion status is displayed in real time. Finally, effective engineering data such as the outer diameter of the wire harness under different cable layouts, the position coordinates of all cables, and the cable layout diagram can be obtained.

[0124] 4. By allowing manual adjustment of the cable position, it simulates the human adjustment that may exist in actual projects.

[0125] 5. By allowing the maximum allowable overlap value of the cable to be set, the elastic deformation and shrinkage of the cable can be simulated.

[0126] 6. By allowing the coordinate axis display ratio to be set, effective calculation accuracy and display effect can be achieved.

[0127] Therefore, combined with the key technical points of the present invention, the fast and accurate wiring harness cable layout and wiring harness outer diameter simulation calculation method achieved by the present invention has important engineering application value.

[0128] Those skilled in the art will appreciate that the above are only preferred embodiments of the present invention, and the various embodiments of the present disclosure and / or the features described in the claims may be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or perform equivalent substitutions on some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0129] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A wire harness cable layout and outer diameter simulation calculation method based on discrete elements, characterized in that: The following steps are involved: 1) Obtain all cable numbers and diameter information through the data interface or text editor input method, perform data validity check, import into the calculation system, and display the import status for easy inspection and verification; 2) Based on the number and diameter information of all cables, the random position algorithm is used to simulate the random position state of the cables before the harness is tied; 3) Based on the cable position status before harness binding and setting calculation assumptions, simulate the movement of cables during the harness binding and tightening process to obtain the final coordinate values ​​of all cables, cable layout diagram and harness outer diameter value.

2. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 1, characterized in that: The step 2) comprises the following steps: 2-1) Set the initial maximum outer diameter of the harness and display it using auxiliary operation A1; 2-2) Traverse all cables to be randomly placed, and determine the value interval [X] of the x-coordinate of the cable i to be placed according to the outer diameter of the harness and the cable diameter, which ensures that the cable position is within the outer diameter envelope of the harness; 2-3) Randomly generate the x coordinate of the cable i to be placed according to the value interval [X] of the x coordinate of the cable i, and initialize the value interval [Y] of the y coordinate of the cable i, which ensures that the cable position is within the outer diameter envelope of the harness; 2-4) Traverse all the cables that have been placed, and determine the coordinate interval [y] where interference will occur between the cable i to be placed and the cable j that has been placed; 2-5) traverse the y-coordinate value interval [Y] of the cable i to be placed, determine the relationship between the nth segment value [Yn] of the interval [Y] and [y], and adjust [Yn] so that it does not contain [y]; 2-6) If the y-coordinate value interval [Y] of the cable i to be placed is an empty set, return to step 2-3); otherwise, randomly generate the y-coordinate of the cable i within the y-coordinate value interval [Y], and combine it with the x-coordinate determined in step 2-3) to obtain the placement coordinates of the cable i to be placed, and place the cable according to the coordinates; if the calculation exceeds the set maximum number of cycles, [Y] is always an empty set, return to step 2-1) to increase the initial outer diameter of the harness; 2-7) After the cable position is randomly initialized, the cable position is allowed to be manually adjusted through auxiliary operation A2 to simulate the human adjustment that may exist in actual engineering.

3. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 2, characterized in that: The auxiliary operation A1 is a method for adjusting the display ratio of the coordinate axis, which determines the interval size of the x and y coordinate axes by adjusting the screen resolution and the coordinate axis ratio, and then adjusts the initial outer diameter of the wire harness; The auxiliary operation A2 is to manually adjust the cable position after the random initial position and after the outer diameter shrinkage calculation of the harness. The adjusted position must meet the following conditions: Within the outer diameter envelope of the harness; and the contact overlap with the outer diameter envelope of the harness is within the maximum allowable value; at the same time, the contact overlap with all other cable circles is within the maximum allowable value.

4. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 2, characterized in that: In the steps 2-2) to 2-4): The value range [X] of the x-direction coordinate of the cable i to be placed is: [-(Rr i ),(Rr i )]; According to the outer diameter of the harness and the x-coordinate of the cable i to be placed, the cable y-coordinate value range [Y] is initialized as: When | r i -r j |>|x i -x j |, the y value interval [y] where the cable to be placed i interferes with the placed cable j is: Where R is the outer diameter of the harness, r i 、x i ,y i is the diameter and coordinates of the cable to be placed, r j 、x j ,y j are the diameter and coordinates of the placed cables.

5. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 2, characterized in that: The steps 2-5) are specifically: If the relationship between interval [y] and the nth segment value [Yn] of interval [Y] is: there is partial overlap, then the overlapping part is cancelled; If the relationship between the interval [y] and the nth value [Yn] of the interval [Y] is: Then the adjustment interval [Yn] is two discontinuous intervals; If the relationship between the interval [y] and the nth value [Yn] of the interval [Y] is: Then cancel the interval [Yn].

6. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 1, characterized in that: The calculation assumptions include: a. All forces on the cable only consider the elastic extrusion force caused by contact overlap, and do not consider the friction between boundaries; b. Each time the harness is retracted, the cable moves to a new position due to external force and stops; c. The force between cables is a passive conductive force. Since its value is proportional to the overlap between cables, the contact force between cables is set equal to the overlap value. d. The contact force between the cable and the harness is the main driving force of the movement process. The specific value needs to be calculated in combination with the force between the cables to ensure the correct movement of the cables; e. The position movement vector of the cable in each calculation cycle is equal to its resultant force vector.

7. The method for calculating the layout and outer diameter of a wiring harness cable based on discrete elements according to claim 1, characterized in that: The step 3) comprises the following steps: 3-1) The outer diameter envelope of the harness is gradually contracted according to the set step length. Each contraction is a main calculation cycle. To achieve process visualization and calculation accuracy, the contraction step length is one display pixel unit; and the auxiliary operation A3 is used to set the maximum allowable overlap value of the cable; 3-2) Calculate the stress between all cables and on the boundaries of the harness after the outer diameter envelope of the harness shrinks or the cable moves for one cycle; 3-3) Determine the calculation strategy based on the cable stress conditions and boundary constraints: If all cables are not stressed, or the movement calculation cycle exceeds the maximum setting value, return to step 3-1), and the outer diameter of the harness continues to shrink; If the cable is under stress, the contact overlap between the cable and the harness is within the maximum allowable value, and the movement calculation cycle is within the maximum set value, go to step 3-4) and move the cable to a new position; If the contact and overlap between the cable and the harness reaches the maximum allowable value, proceed to step 3-5) and the outer diameter of the harness is shrunk; 3-4) moving the cables to new positions according to the stress conditions of all cables, and returning to step S3-2) to recalculate the stress conditions of all cables; 3-5) When the contact and overlap between the cable and the harness reaches the maximum allowable value, the harness outer diameter is shrunk, and the harness outer diameter value, all cable coordinate values, and cable layout diagram are obtained; if you are not satisfied with the calculation results, adjust the cable position by using auxiliary operation A2, and then return to step 3-1) for multiple iterative calculations.

8. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 7, characterized in that: The auxiliary operation A3 is specifically: Set the maximum allowable cable contact overlap value. This value is defined as the maximum number of pixels allowed for the cable circle to overlap with other cable circles and the outer diameter circle of the harness, and is understood as the cable elasticity value to prevent cable movement from getting stuck.

9. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 7, characterized in that: The step 3-2) is specifically: (1) Obtaining the contact force between cables: The resultant force vector on each cable is the superposition of the force vectors of all cables that are in contact and overlap with other cables, that is: F a线缆间合力 =F ab +F ac +...F an Among them, F ab =F ba , F ac =F ca , F an =F na , n is the number of the last cable; (2) Obtain the contact force between the cable and the harness: If the cable overlaps with the outer diameter of the harness, the force direction points to the center of the harness, and the contact force value is the overlap value multiplied by the adjustment coefficient k to ensure that the cable moves correctly to the envelope track that contacts and does not overlap with the harness; the k value is transformed into a quadratic equation by the following equation, that is: ||F a线缆间合力 +k×F a线束 +P a ||2=R-r a Where R is the outer diameter of the harness, P a 、r a are the current coordinate matrix and diameter of cable a respectively; the small value solution of the above formula is the adjacent position; the large value solution is the position on the other side symmetrical to the center of the harness; (3) Obtain the resultant force on the cable: The resultant force on the cable is the sum of the contact force vector between the cables and the contact force vector of the harness, that is: F a合力 =F a线缆间合力 +F a线束 。 10. The method for calculating wiring harness cable layout and outer diameter simulation based on discrete elements according to claim 7, characterized in that: In step 3-4), the moving cable to a new location is: P' a =P a +F a合力 Among them, P a , P' a are the coordinates before and after the cable moves, F a合力 is the vector of the resultant force acting on the cable.

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