An Optimization Method, Device, Electronic Equipment and Storage Medium for the Transmission Efficiency of NW-Type Compound Planetary Gear Train Based on Intelligent Optimization

Abstract

The present application provides an optimization method, device, electronic device and storage medium for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization. The method includes: obtaining multiple groups of initial tooth profile modification parameters, which are used to modify the teeth of the gears in the NW-type compound planetary gear train; calculating according to the multiple groups of initial tooth profile modification parameters to obtain the fitness value of each group of initial tooth profile modification parameters, and the fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters; performing iterative calculations on the multiple groups of initial tooth profile modification parameters through an intelligent optimization algorithm to obtain target tooth profile modification parameters, where the target tooth profile modification parameters are tooth profile modification parameters that meet preset conditions, the intelligent optimization algorithm includes a multi-objective genetic algorithm, and the preset conditions are used to indicate the transmission efficiency and friction loss of the gears; adjusting the tooth profile of the gears in the NW-type compound planetary gear train by using the target tooth profile modification parameters. The present application can improve the transmission efficiency of the NW-type compound planetary gear train.

Description

Technical Field

[0001] The present application relates to the field of machinery, and in particular, to an optimization method, device, electronic device, and storage medium for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization. Background Art

[0002] There is a single and double tooth alternating meshing phenomenon in the NW-type compound planetary gear train, which causes the load distribution borne by the gears to change suddenly at different time points, easily leading to local stress concentration and an increase in impact load, thereby affecting the transmission smoothness and gear life. When calculating the gear transmission efficiency by the traditional power method, it is usually assumed that the load distribution is uniform, and the problem of sudden load changes during actual operation is not fully considered. Therefore, when designing the tooth profile of the NW-type compound planetary gear train, it is impossible to carry out targeted optimization according to the meshing characteristics of the NW-type compound planetary gear train, resulting in a low transmission efficiency of the NW-type compound planetary gear train. Summary of the Invention

[0003] The main purpose of the embodiments of the present application is to propose an optimization method, device, electronic device, and storage medium for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization, aiming to solve the problem of low transmission efficiency of the existing NW-type compound planetary gear train.

[0004] To achieve the above object, a first aspect of the embodiments of the present application proposes an optimization method for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization, and the method includes:

[0005] Obtain multiple groups of initial tooth profile modification parameters, where the initial tooth profile modification parameters are used to modify the gears in the NW-type compound planetary gear train;

[0006] Calculate according to multiple groups of the initial tooth profile modification parameters to obtain the fitness value of each group of the initial tooth profile modification parameters, where the fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters;

[0007] Perform iterative calculation on multiple groups of the initial tooth profile modification parameters through an intelligent optimization algorithm to obtain target tooth profile modification parameters, where the target tooth profile modification parameters are tooth profile modification parameters that meet preset conditions, the intelligent optimization algorithm includes a multi-objective genetic algorithm, and the preset conditions are used to indicate the transmission efficiency and friction loss of the gears;

[0008] Adjust the tooth profile of the gears in the NW-type compound planetary gear train by using the target tooth profile modification parameters.

[0009] In some embodiments, the calculating according to multiple groups of the initial tooth profile modification parameters to obtain the fitness value of each group of the initial tooth profile modification parameters includes:

[0010] Calculate each group of the initial tooth profile modification parameters through the rolling friction calculation equation to obtain the friction loss of each group of the tooth profile modification parameters, where the rolling friction calculation equation is used to calculate the friction loss of the gear;

[0011] Calculate each group of the initial tooth profile modification parameters through the instantaneous transmission efficiency calculation equation to obtain the transmission efficiency of each group of the tooth profile modification parameters, where the instantaneous transmission efficiency calculation equation is used to calculate the transmission efficiency of the gear;

[0012] Obtain the fitness value of each group of the initial tooth profile modification parameters according to the friction loss and the transmission efficiency of each group of the tooth profile modification parameters.

[0013] In some embodiments, the NW type compound planetary gear train includes a driving wheel and a driven wheel;

[0014] The rolling friction calculation equation is constructed based on the rolling friction coefficient and the load force, and the load force is determined according to the load distribution of the NW type compound planetary gear train;

[0015] Wherein, the rolling friction coefficient is calculated according to the following steps:

[0016] Calculate based on the geometric parameters of the driving wheel and the geometric parameters of the driven wheel to obtain a recovery coefficient, where the recovery coefficient is used to characterize the ability of the gear material to return to its original state after being deformed by force;

[0017] Calculate based on the load force, the comprehensive radius of curvature, the recovery coefficient, the cylindrical axial length, and the pressure angle to obtain an elastic hysteresis coefficient, where the comprehensive radius of curvature is determined according to the radius of curvature of the driving wheel and the radius of curvature of the driven wheel, and the elastic hysteresis coefficient is used to characterize the delay phenomenon when the gear returns to its original state after being deformed by force;

[0018] Calculate based on the recovery coefficient, the elastic hysteresis coefficient, the comprehensive radius of curvature, and the cylindrical axial length to obtain the rolling friction coefficient.

[0019] In some embodiments, the geometric parameters of the driving wheel include the elastic modulus of the driving wheel and the Poisson's ratio of the driving wheel, and the geometric parameters of the driven wheel include the elastic modulus of the driven wheel and the Poisson's ratio of the driven wheel;

[0020] The calculation based on the geometric parameters of the driving wheel and the geometric parameters of the driven wheel to obtain a recovery coefficient includes:

[0021] Take the ratio of the elastic modulus of the driving wheel to the Poisson's ratio of the driving wheel as the first value;

[0022] Take the ratio of the elastic modulus of the driven wheel to the Poisson's ratio of the driven wheel as the second value;

[0023] Take the sum of the first value and the second value as the third value;

[0024] Obtain the restitution coefficient according to the product of the third value and a preset first coefficient.

[0025] In some embodiments, the calculating the elastic hysteresis coefficient according to the load force, the comprehensive radius of curvature, the restitution coefficient, the cylindrical axial length, and the pressure angle includes:

[0026] Take the ratio of the tangent function of the pressure angle to the restitution coefficient as the fourth value;

[0027] Take the product of the comprehensive radius of curvature and the cylindrical axial length as the fifth value;

[0028] Take the ratio of the fifth value to the load force as the sixth value;

[0029] Calculate the elastic hysteresis coefficient according to the fourth value and the sixth value.

[0030] In some embodiments, the instantaneous transmission efficiency calculation equation is obtained according to the following steps:

[0031] Construct an initial instantaneous transmission efficiency calculation equation according to the output power and the input power of the NW-type compound planetary gear train;

[0032] Adjust the initial instantaneous transmission efficiency calculation equation according to the single and double tooth alternating meshing phenomenon during the operation of the NW-type compound planetary gear train and the rolling friction coefficient to obtain the instantaneous transmission efficiency calculation equation.

[0033] In some embodiments, the comprehensive radius of curvature is calculated according to the following steps:

[0034] Take the product of the pressure angle and the pitch diameter of the driving wheel as the seventh value;

[0035] Multiply the second preset coefficient by the seventh value to obtain the radius of curvature of the driving wheel;

[0036] Take the ratio of the number of teeth of the driving wheel to the number of teeth of the driven wheel as the eighth value;

[0037] Take the difference between the eighth value and the second preset coefficient as the ninth value;

[0038] Multiply the seventh value by the ninth value to obtain the radius of curvature of the driven wheel;

[0039] Add the reciprocal of the radius of curvature of the driving wheel to the reciprocal of the radius of curvature of the driven wheel to obtain the comprehensive radius of curvature.

[0040] Add the reciprocal of the radius of curvature of the driving wheel to the reciprocal of the radius of curvature of the driven wheel to obtain the comprehensive radius of curvature.

[0041] To achieve the above object, a second aspect of the embodiments of the present application provides an optimization device for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization. The device includes:

[0042] An acquisition module, configured to acquire multiple groups of initial tooth profile modification parameters, where the initial tooth profile modification parameters are used to modify the gears in the NW-type compound planetary gear train;

[0043] A calculation module, configured to calculate according to multiple groups of the initial tooth profile modification parameters to obtain the fitness value of each group of the initial tooth profile modification parameters, where the fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters;

[0044] An iteration module, configured to perform iterative calculation on multiple groups of the initial tooth profile modification parameters through an intelligent optimization algorithm to obtain target tooth profile modification parameters, where the target tooth profile modification parameters are tooth profile modification parameters that meet preset conditions, the intelligent optimization algorithm includes a multi-objective genetic algorithm, and the preset conditions are used to indicate the transmission efficiency and frictional loss of the gears;

[0045] An adjustment module, configured to adjust the tooth profile of the gears in the NW-type compound planetary gear train by using the target tooth profile modification parameters.

[0046] To achieve the above object, a third aspect of the embodiments of the present application provides an electronic device, where the electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the method for optimizing the transmission efficiency of the NW-type compound planetary gear train based on intelligent optimization described in the first aspect above.

[0047] To achieve the above object, a fourth aspect of the embodiments of the present application provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the method for optimizing the transmission efficiency of the NW-type compound planetary gear train based on intelligent optimization described in the first aspect above.

[0048] The optimization method, device, electronic device and storage medium for the transmission efficiency of the NW-type compound planetary gear train based on intelligent optimization proposed in this application obtain multiple groups of initial tooth profile modification parameters, calculate the fitness value of each group of initial tooth profile modification parameters, comprehensively consider the transmission efficiency and friction loss of each group of initial tooth profile modification parameters through the fitness value, perform iterative calculations on multiple groups of initial tooth profile modification parameters through an intelligent optimization algorithm until the preset conditions are met, stop the iteration to obtain the target tooth profile modification parameters, determine the optimal solution when the tooth profile modification parameters take into account both transmission efficiency and friction loss through the intelligent optimization algorithm, and adjust the contour of the gears in the NW-type compound planetary gear train through the target tooth profile modification parameters to obtain an NW-type compound planetary gear train with better transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 FIG. is a schematic flowchart of the optimization method for the transmission efficiency of the NW-type compound planetary gear train based on intelligent optimization provided by an embodiment of the present application;

[0050] Figure 2 FIG. is a schematic diagram of the model of the NW-type compound planetary gear train provided by an embodiment of the present application;

[0051] Figure 3 FIG. is a schematic diagram of the single and double tooth alternating meshing phenomenon in the NW-type compound planetary gear train provided by an embodiment of the present application;

[0052] Figure 4 FIG. is a schematic structural diagram of the optimization device for the transmission efficiency of the NW-type compound planetary gear train based on intelligent optimization provided by an embodiment of the present application;

[0053] Figure 5 FIG. is a schematic hardware structure diagram of the electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0055] It should be noted that although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from the module division in the device or the flowchart. Terms such as "first" and "second" in the specification, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0057] The NW type compound planetary gear train has the phenomenon of alternating single and double teeth meshing, which causes a sudden change in the load distribution of the gears at different time points, easily leading to local stress concentration and increased impact load, thereby affecting the transmission smoothness and gear life. When the traditional power method calculates the gear transmission efficiency, it is usually assumed that the load distribution is uniform, and the problem of sudden load changes in actual operation is not fully considered. Therefore, when designing the tooth shape of the NW type compound planetary gear train, it is impossible to perform targeted optimization according to the meshing characteristics of the NW type compound planetary gear train, resulting in a low transmission efficiency of the NW type compound planetary gear train.

[0058] Based on this, the embodiments of the present application provide a method, device, electronic device and storage medium for optimizing the transmission efficiency of a NW-type compound planetary gear train based on intelligent optimization, aiming to solve the problem of low transmission efficiency of the existing NW-type compound planetary gear train.

[0059] The embodiments of the present application provide a method, device, electronic device and storage medium for optimizing the transmission efficiency of a NW-type compound planetary gear train based on intelligent optimization, which are specifically illustrated through the following embodiments. First, a method for optimizing the transmission efficiency of a NW-type compound planetary gear train based on intelligent optimization in the embodiments of the present application is described.

[0060] The embodiments of the present application can acquire and process relevant data based on artificial intelligence technology. Artificial Intelligence (AI) is the theory, method, technology and application system that uses digital computers or machines controlled by digital computers to simulate, extend and expand human intelligence, perceive the environment, acquire knowledge and use knowledge to obtain the best results.

[0061] AI basic technologies generally include sensors, dedicated AI chips, cloud computing, distributed storage, big data processing technology, operation / interaction systems, mechatronics, etc. AI software technologies mainly include computer vision technology, robotics technology, biometrics technology, speech processing technology, natural language processing technology, and machine learning / deep learning.

[0062] An optimization method for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization provided by an embodiment of the present application relates to the mechanical field. The optimization method for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization provided by an embodiment of the present application can be applied to a terminal, can also be applied to a server side, or can also be software running on a terminal or a server side. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, etc.; the server side can be configured as an independent physical server, can also be configured as a server cluster or a distributed system composed of multiple physical servers, or can also be configured as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application for implementing an optimization method for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization, etc., but is not limited to the above forms.

[0063] The present application can be used in many general or specific computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet-type devices, multi-processor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network PCs, small computers, large computers, distributed computing environments including any of the above systems or devices, and so on. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0064] It should be noted that in each specific embodiment of the present application, when it comes to performing relevant processing based on data related to the user's identity or characteristics such as user information, user behavior data, user historical data, and user location information, the user's permission or consent will be obtained first, and moreover, the collection, use, and processing of these data will comply with relevant laws, regulations, and standards. In addition, when an embodiment of the present application needs to obtain sensitive personal information of the user, the user's separate permission or separate consent will be obtained through methods such as pop-up windows or redirecting to a confirmation page. After clearly obtaining the user's separate permission or separate consent, the necessary user-related data for enabling the normal operation of the embodiment of the present application will be obtained.

[0065] Figure 1The following is a schematic flowchart of an optimization method for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization provided by an embodiment of the present application. Please refer to Figure 1 An optimization method for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization provided by an embodiment of the present application may include, but is not limited to, steps S101 to S104.

[0066] Step S101: Obtain multiple groups of initial tooth profile modification parameters, where the initial tooth profile modification parameters are used to modify the gears in the NW-type compound planetary gear train.

[0067] In this step, each group of initial tooth profile modification parameters can be randomly generated or historical tooth profile modification parameters, which are not limited herein. Each group of initial tooth profile modification parameters includes, but is not limited to, the maximum modification amount, the modification length, and the modification curve.

[0068] In this implementation, as Figure 2 shown, the NW-type compound planetary gear train includes an upper-level first-stage planetary gear and a sun gear forming a gear pair, a lower-level first-stage planetary gear and a sun gear forming a gear pair, the upper and lower first-stage planetary gears are respectively connected to the second-stage planetary gears, and the upper and lower second-stage planetary gears and the fixed ring gear form a gear pair. (Definition of gear pair: The basic structure composed of two meshing gears)

[0069] Step S102: Calculate according to multiple groups of the initial tooth profile modification parameters to obtain the fitness value of each group of the initial tooth profile modification parameters, where the fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters.

[0070] In this step, according to each group of initial tooth profile modification parameters, a corresponding gear tooth profile model is generated. By calculating the fitness value of the gear tooth profile model corresponding to each group of initial tooth profile modification parameters, the fitness value of the gear tooth profile model is used as the fitness value of the corresponding initial tooth profile modification parameters.

[0071] Furthermore, a fitness value calculation function is established according to actual requirements, and the fitness value of each gear tooth profile model is calculated through a preset fitness calculation function. The fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters.

[0072] In some embodiments, after obtaining the fitness value corresponding to each group of initial tooth profile modification parameters, the fitness values corresponding to each group of initial tooth profile modification parameters are sorted to improve the iteration efficiency of the intelligent optimization method.

[0073] Exemplarily, a fitness value calculation function is established according to the transmission efficiency and friction loss of the gear. The fitness value calculation function can be expressed by Equation 1 below:

[0074] Fitness = a * A + b * B + U (1);

[0075] In the formula, Fitness represents the fitness value, a represents the weight corresponding to the transmission efficiency, b represents the weight corresponding to the friction loss, A represents the transmission efficiency, B represents the friction loss, and U represents the penalty term.

[0076] Among them, the weight corresponding to the transmission efficiency, the weight corresponding to the friction loss, and the penalty term can be set according to the actual situation. The penalty term is used to handle the problem of parameter out-of-bounds. For example, when the modification amount exceeds the allowable range, the fitness value is increased.

[0077] Step S103: Perform iterative calculations on multiple groups of the initial tooth profile modification parameters through an intelligent optimization algorithm to obtain the target tooth profile modification parameters. The target tooth profile modification parameters are tooth profile modification parameters that meet the preset conditions. The intelligent optimization algorithm includes a multi-objective genetic algorithm, and the preset conditions are used to indicate the transmission efficiency and friction loss of the gear.

[0078] In this step, the intelligent optimization algorithm includes a multi-objective genetic algorithm. The iterative optimization process of the multi-objective genetic algorithm is as follows: Obtain multiple groups of initial tooth profile modification parameters as the initial population, and each group of initial tooth profile modification parameters is used as an individual; Calculate the fitness value of each group of initial tooth profile modification parameters; Sort the individuals in the population according to the Pareto dominance relationship to determine the non-dominated solution sets of different levels. Among them, the dominance relationship means that one solution is better than another solution in all objectives. In the non-dominated solution set, the individuals in the population are divided into different fronts, and the first front contains all non-dominated solutions; Calculate the crowding degree of the individuals in each front; Use binary tournament selection to select parent individuals, and generate a new generation of solutions through simulated binary crossover and polynomial mutation; If the objective function converges to a stable Pareto solution set, output the target tooth profile modification parameters.

[0079] It should be noted that the objective function can be set according to the actual situation and is not limited here.

[0080] Step S104: Adjust the tooth profile of the gears in the NW type compound planetary gear train by using the target tooth profile modification parameters.

[0081] In this step, the target tooth profile modification parameters include but are not limited to the rolling angle of the pinion in the modification section, the rolling angle at the starting point of the pinion modification, the rolling angle at the starting point of the pinion modification, the modification power exponent, the maximum modification amount, and the modification length.

[0082] Furthermore, determine the modification curve through the rolling angle of the pinion in the modification section, the rolling angle at the starting point of the pinion modification, the rolling angle at the starting point of the pinion modification, the modification power exponent, and the maximum modification amount.

[0083] It should be noted that the pinion is the gear with fewer teeth in the gear pair.

[0084] Specifically, the modification curve can be expressed by the following formula (2):

[0085] (2);

[0086] In the formula, represents the modification curve, represents the rolling angle of the pinion in the modification section, represents the maximum modification amount, represents the rolling angle at the starting point of the pinion modification, represents the rolling angle at the ending point of the pinion modification, represents the modification power exponent.

[0087] In the NW-type compound planetary gear train, due to the phenomenon of single and double tooth alternate meshing, in the single tooth meshing area, the load is completely borne by a pair of teeth, while in the double tooth meshing area, the load is shared by two pairs of teeth. Since the load in the single tooth meshing area is significantly higher than that in the double tooth meshing area, it is easy to cause excessive local tooth surface stress, exacerbate fatigue damage, and the load distribution during gear meshing shows periodic changes.

[0088] In this implementation manner, according to the modification curve, the maximum modification amount, and the modification length, the tooth profile of the gears in the NW-type compound planetary gear train is adjusted and modified to optimize the contact state of the gears in the NW-type compound planetary gear train, improve the uniformity of the load distribution during the entire meshing process, reduce the local stress concentration effect, thereby improving the fatigue life and transmission efficiency of the NW-type compound planetary gear train. Among them, the tooth profile modification is to remove a part of the interfering material from the tooth surface along the tooth height direction, thereby changing the shape of the tooth profile and the load distribution.

[0089] In this implementation manner, by obtaining multiple groups of initial tooth profile modification parameters, calculating the fitness value of each group of initial tooth profile modification parameters, comprehensively considering the transmission efficiency and friction loss of each group of initial tooth profile modification parameters through the fitness value, performing iterative calculations on multiple groups of initial tooth profile modification parameters through an intelligent optimization algorithm until the preset conditions are met and the iteration stops to obtain the target tooth profile modification parameters, determining the optimal solution when the tooth profile modification parameters take into account both transmission efficiency and friction loss through the intelligent optimization algorithm, and adjusting the contour of the gears in the NW-type compound planetary gear train through the target tooth profile modification parameters to obtain a NW-type compound planetary gear train with better transmission efficiency.

[0090] In some implementation manners, in the calculation according to multiple groups of the initial tooth profile modification parameters in step S102 to obtain the fitness value of each group of the initial tooth profile modification parameters, it may include but is not limited to steps S1021 to S1023.

[0091] Step S1021: Calculate the friction loss of each group of the initial tooth profile modification parameters through the rolling friction force calculation equation, where the rolling friction force calculation equation is used to calculate the friction loss of the gear.

[0092] Step S1022: Calculate the transmission efficiency of each group of the initial tooth profile modification parameters through the instantaneous transmission efficiency calculation equation, where the instantaneous transmission efficiency calculation equation is used to calculate the transmission efficiency of the gear.

[0093] Step S1023: Obtain the fitness value of each group of the initial tooth profile modification parameters according to the friction loss and transmission efficiency of each group of the tooth profile modification parameters.

[0094] In this implementation manner, both the rolling friction force calculation equation and the instantaneous efficiency calculation equation can be set according to the actual situation and are not limited herein. For example, the rolling friction force calculation equation can adopt the elastohydrodynamic lubrication (EHL) equation, and the instantaneous efficiency calculation equation can adopt the ratio of the output power to the input power of the NW-type compound planetary gear train.

[0095] In this implementation manner, a fitness value calculation function is preset in advance. The setting method of the fitness value calculation function can be referred to the description in Step S102 and will not be elaborated herein; according to each group of the initial tooth profile modification parameters, a corresponding gear tooth profile model is generated. The rolling friction loss of the gear tooth profile model corresponding to each group of the initial tooth profile modification parameters is calculated through the rolling friction force calculation equation, and the rolling friction loss of the gear tooth profile model is used as the rolling friction loss of the corresponding initial tooth profile modification parameters. The transmission efficiency of the gear tooth profile model corresponding to each group of the initial tooth profile modification parameters is calculated through the instantaneous transmission efficiency calculation equation, and the transmission efficiency of the gear tooth profile model is used as the transmission efficiency of the corresponding initial tooth profile modification parameters. The rolling friction loss and transmission efficiency corresponding to each group of the initial tooth profile modification parameters are substituted into the preset fitness value calculation function to obtain the fitness value of each group of the initial tooth profile modification parameters.

[0096] In this embodiment, the friction loss and transmission efficiency of the NW-type compound planetary gear train are accurately calculated through the rolling friction force calculation equation and the instantaneous efficiency calculation equation, so as to accurately calculate the fitness value of each group of the initial tooth profile modification parameters, which is convenient for iteratively obtaining more tooth profile modification parameters that meet the actual requirements in the subsequent steps.

[0097] In some embodiments, the rolling friction force calculation equation is constructed based on the rolling friction coefficient and the load force, and the load force is determined according to the load distribution of the NW-type compound planetary gear train.

[0098] Furthermore, based on the influence of tooth surface error on the load distribution coefficient, a deformation coordination equation is established to determine the load distribution coefficient at the meshing position. The load distribution is determined according to the load distribution coefficient, thereby obtaining the load force.

[0099] Furthermore, the deformation coordination equation can be expressed by Equation (3) below:

[0100] (3);

[0101] In the formula, represents the gear transmission flexibility matrix, which is used to describe the influence of local deformation at the contact point; represents the overall deformation flexibility matrix of the gear, which is used to describe the elastic deformation influence of the gear at different meshing points; represents the influence flexibility matrix of tooth profile modification on deformation; represents the deformation flexibility matrix considering errors; represents the identity matrix.

[0102] Furthermore, the load vector at the meshing point can be expressed by Equation (4) below:

[0103] (4);

[0104] In the formula, represents the load vector at the meshing point.

[0105] The clearance vector can be expressed by Equation (5) below:

[0106] (5);

[0107] In the formula, represents the clearance vector.

[0108] Among them, the clearance of the th meshing point can be calculated by Equation (6) below:

[0109] (6);

[0110] In the formula, represents the clearance of the th meshing point, represents the gear separation distance, which is used to describe the phenomenon of early engagement and delayed disengagement of the loaded gear, represents the tooth surface error correction amount.

[0111] Further, set the initial contact force and iteration conditions. Specifically, during the solution process, to simplify the starting state and facilitate subsequent iterative solution, initially, it is assumed that the contact forces borne by all potential meshing points are equal, that is, the load at each meshing point is evenly distributed. The initial contact force can be expressed by Equation 7 below; according to the overall force balance, the sum of the meshing forces at all potential meshing points must be equal to the total load of the system , thus obtaining the iteration conditions, which can be expressed by Equation 8 below:

[0112] (7);

[0113] (8);

[0114] Combining the above Equations 3 to 8, the final load distribution coefficient can be obtained, and the load distribution coefficient can be expressed by Equation 9 below:

[0115] (9);

[0116] In the formula, represents the load distribution coefficient, indicating the proportion of the load at a certain meshing point to the total load, represents the total load, represents the meshing force of the

[0117] By constructing a deformation coordination equation, setting the initial load, introducing the meshing clearance and error effects, and satisfying the total load balance constraint, the actual forces on each meshing point can finally be solved, and then the load distribution coefficient can be determined. Among them, the rolling friction coefficient is calculated according to the following steps S201 to S203:

[0118] Step S201: Calculate according to the geometric parameters of the driving wheel and the geometric parameters of the driven wheel to obtain a recovery coefficient, which is used to characterize the ability of the gear material to return to its original state after being deformed by force;

[0119] Step S202: Calculate according to the load force, the comprehensive curvature radius, the recovery coefficient, the cylindrical axial length, and the pressure angle to obtain an elastic hysteresis coefficient. The comprehensive curvature radius is determined according to the curvature radius of the driving wheel and the curvature radius of the driven wheel. The elastic hysteresis coefficient is used to characterize the delay phenomenon when the gear returns to its original state after being deformed by force;

[0120] Step S203: Calculate according to the recovery coefficient, the elastic hysteresis coefficient, the comprehensive curvature radius, and the cylindrical axial length to obtain the rolling friction coefficient.

[0121] In this implementation, each gear pair in the NW type compound planetary gear train includes a driving gear and a driven gear. The rolling friction coefficient can be multiplied by the load force to obtain the rolling friction force. The rolling friction force calculation equation can be expressed by Equation (10) below:

[0122] (10);

[0123] In the formula, represents the rolling friction force, represents the rolling friction coefficient, represents the load force.

[0124] According to the change of the gear load distribution coefficient, determine the load distribution in the gear contact area to obtain the change of the normal load during single and double tooth alternation. Considering the material properties of the gear, calculate the recovery coefficient k and the elastic hysteresis loss coefficient ξ to obtain the dynamic rolling friction coefficient.

[0125] Specifically, the rolling friction coefficient can be calculated by Equation (11) below:

[0126] (11);

[0127] In the formula, represents the rolling friction coefficient, represents the tangential force, represents the normal force, represents the elastic hysteresis coefficient, represents the half-width of the contact area, represents the comprehensive curvature radius, represents the load force, represents the elastic modulus, represents the recovery coefficient.

[0128] In this embodiment, combining the tooth surface lubrication characteristics and the elastohydrodynamic lubrication theory to construct a dynamic friction coefficient equation can more accurately reflect the actual operating state of the gear, improve the accuracy of the transmission efficiency calculation, and provide a more reliable theoretical support for the tooth profile optimization design.

[0129] In some embodiments, in the calculation according to the geometric parameters of the driving gear and the geometric parameters of the driven gear in step S201 to obtain the recovery coefficient, it may include but is not limited to steps S2011 to S2014.

[0130] Step S2011: Take the ratio of the elastic modulus of the driving gear to the Poisson's ratio of the driving gear as the first value.

[0131] Step S2012: Take the ratio of the elastic modulus of the driven gear to the Poisson's ratio of the driven gear as the second value.

[0132] Step S2013: Take the sum of the first value and the second value as the third value.

[0133] Step S2014: Obtain the recovery coefficient according to the product of the third value and a preset first coefficient.

[0134] Specifically, the recovery coefficient can be calculated by the following formula (12):

[0135] (12);

[0136] In the formula, represents the recovery coefficient, represents the elastic modulus of the driving wheel, represents the elastic modulus of the driven wheel, represents the Poisson's ratio of the driving wheel, represents the Poisson's ratio of the driven wheel.

[0137] Among them, is denoted as the first value, is denoted as the second value, is denoted as the third value, is denoted as the first coefficient.

[0138] In some embodiments, in step S202, calculating the elastic hysteresis coefficient according to the load force, the comprehensive curvature radius, the recovery coefficient, the cylindrical axial length, and the pressure angle may include, but is not limited to, steps S2021 to S2024.

[0139] Step S2021: Take the ratio of the tangent value of the pressure angle to the recovery coefficient as the fourth value.

[0140] Step S2022: Take the product of the comprehensive curvature radius and the cylindrical axial length as the fifth value.

[0141] Step S2023: Take the ratio of the fifth value to the load force as the sixth value.

[0142] Step S2024: Calculate the elastic hysteresis coefficient according to the fourth value and the sixth value.

[0143] Specifically, the elastic hysteresis loss coefficient can be calculated by the following formula (13):

[0144] (13);

[0145] In the formula, represents the elastic hysteresis loss coefficient, represents the pressure angle, represents the comprehensive curvature radius, represents the cylindrical axial length, Indicates the load force.

[0146] in, Recorded as the fourth value, Recorded as the fifth value, Recorded as the sixth value.

[0147] It should be noted that, under normal circumstances, two gears can only mesh with each other when the pressure angles are the same, so when calculating, it is not distinguished whether the pressure angle belongs to the driving wheel or the driven wheel.

[0148] In some embodiments, the instantaneous transfer efficiency calculation equation is obtained according to the following steps S301 to S302:

[0149] Step S301, constructing an initial instantaneous transfer efficiency calculation equation according to the output power and input power of the NW type compound planetary gear train;

[0150] Step S302: adjusting the initial instantaneous transmission efficiency calculation equation according to the single- and double-tooth alternating meshing phenomenon and the rolling friction coefficient when the NW type compound planetary gear train is running, to obtain an instantaneous transmission efficiency calculation equation.

[0151] like Figure 3 As shown in the figure, in the NW type compound planetary gear system, in order to ensure the continuity of the fixed transmission ratio transmission of the gears, the meshing line length must be greater than or equal to the base circle pitch to ensure that when the first pair of teeth separates, the second pair of teeth has entered into meshing. In the transmission process, the low overlap gears will have single-tooth meshing areas and double-tooth meshing areas, that is, the single and double teeth are alternately meshed.

[0152] The gear is in front of the node P and after node P Meshing at the meshing point For analysis, assume that the tangential speeds of the driving wheel and the driven wheel at this point are and , It can be expressed by the following formula 14: It can be expressed by the following formula 15:

[0153] (14);

[0154] (15);

[0155] In the formula, represents the tangential speed of the driving wheel at the meshing point, represents the tangential speed of the driven gear at the meshing point, represents the base circle radius of the driving wheel, represents the base circle radius of the driven wheel, represents the pressure angle of the driving wheel, represents the pressure angle of the driven wheel, represents the rotation angle of the driving wheel, represents the meshing point and the meshing point the distance of, represents the meshing point and the meshing point the distance of, represents the rotation angle of the driven wheel.

[0156] According to the definition of instantaneous efficiency, that is, the ratio of output power to input power, an initial instantaneous transmission efficiency calculation equation is constructed, and the initial instantaneous transmission efficiency calculation equation can be expressed by Equation (16) below:

[0157] (16);

[0158] In the formula, represents the instantaneous transmission efficiency, represents the input torque, represents the output torque, represents the rotation angle of the driving wheel, represents the rotation angle of the driven wheel, represents the base circle radius of the driving wheel, represents the base circle radius of the driven wheel.

[0159] To ensure the continuity of the fixed transmission ratio of the gears, when the gears are meshing, it is necessary to meet the continuous transmission condition that the length of the meshing line is greater than or equal to the base pitch, that is, the contact ratio of the gears ≥ 1. When the gears are actually meshing, it is also necessary to consider the phenomenon of single and double tooth alternating meshing and rolling friction. For the convenience of subsequent analysis, in the NW-type compound planetary gear train, two sets of gear pairs are defined as the main meshing tooth pair and the other as the secondary meshing tooth pair. Here, it is not limited which specific gear pair is the main meshing tooth pair and which is the secondary meshing tooth pair.

[0160] Specifically, when the main meshing tooth pair is at the meshing point , and the secondary meshing tooth pair is at the meshing point , the corresponding torque equations can be expressed by Equations (17) and (18) below:

[0161] (17);

[0162] (18);

[0163] In the formula, represents the base circle radius of the driving wheel, represents the base circle radius of the driven wheel, represents the normal load at the first meshing point, represents the normal load at the second meshing point, denotes the distance between the meshing point K and the meshing point ; denotes the base pitch; denotes the coefficient of sliding friction of the driving wheel; denotes the coefficient of sliding friction of the driven wheel; denotes the meshing point and the meshing point ; denotes the radial force component of the first meshing point; denotes the radial component of the second meshing point.

[0164] It should be noted that the coefficient of sliding friction can be set according to the actual situation and is not limited here; generally, the coefficient of sliding friction takes a value between 0.03 and 0.07.

[0165] Among them, the base pitch can be calculated by the following formula (19):

[0166] (19);

[0167] In the formula, denotes the base pitch; denotes the module; denotes the pressure angle.

[0168] Combining the above formulas (16), (17), and (18), the instantaneous transmission efficiency here can be expressed by the following formula (20):

[0169] (20);

[0170] In the formula, denotes the rotation angle of the driving wheel; denotes the rotation angle of the driven wheel, and N denotes the normal load ratio of the driving wheel and the driven wheel, that is, N = .

[0171] Among them, the rotation angle of the driven wheel can be calculated by the following formula (21):

[0172] (21);

[0173] When the main meshing tooth pair is at the meshing point , and the secondary meshing tooth pair is at the meshing point , the corresponding torque equations can be expressed by the following formulas (22) and (23):

[0174] (22);

[0175] (23);

[0176] Combining the above equations 16, 22, and 23, the instantaneous transmission efficiency here can be expressed by the following equation 24:

[0177] (24);

[0178] Combining the above equation 20 and equation 24, and based on the rolling friction and the single and double tooth alternating meshing phenomenon, the calculation equation of the instantaneous transmission efficiency of the NW compound planetary gear train can be derived. The calculation equation of the instantaneous transmission efficiency of the NW compound planetary gear train can be expressed by the following equation 25:

[0179] (25);

[0180] In the formula, represents the rolling friction coefficient of the driving wheel, represents the rolling friction coefficient of the driven wheel, represents the distance from the tooth-out point to the node, represents the distance from the tooth-in point to the node, represents the pressure angle.

[0181] It should be noted that the node is the intersection point between the common normal of the tooth profile contact point and the center line.

[0182] Among them, the distance from the tooth-out point to the node can be calculated by the following equation 26:

[0183] (26);

[0184] The distance from the tooth-in point to the node can be calculated by the following equation 27:

[0185] (27);

[0186] In this embodiment, based on the single and double tooth meshing phenomenon and the rolling friction coefficient of the NW compound planetary gear train, a calculation equation for the instantaneous transmission efficiency is constructed to improve the accuracy of calculating the instantaneous transmission efficiency.

[0187] In some other implementation manners, the above equation 25 can be used as the objective function in step S103.

[0188] In some embodiments, the comprehensive curvature radius is calculated according to the following steps S401 to S406:

[0189] Step S401: Take the product of the pressure angle and the pitch diameter of the driving wheel as the seventh value;

[0190] Step S402: Multiply the second preset coefficient by the seventh value to obtain the curvature radius of the driving wheel;

[0191] Step S403: Take the ratio of the number of teeth of the driving wheel to the number of teeth of the driven wheel as the eighth value;

[0192] Step S404: Take the difference between the eighth value and the second preset coefficient as the ninth value;

[0193] Step S405: Multiply the seventh value by the ninth value to obtain the radius of curvature of the driven wheel;

[0194] Step S406: Add the reciprocal of the radius of curvature of the driving wheel to the reciprocal of the radius of curvature of the driven wheel to obtain the comprehensive radius of curvature.

[0195] Specifically, the radius of curvature of the driving wheel at the meshing point can be calculated by Equation (28) below:

[0196] (28);

[0197] In the formula, represents the radius of curvature of the driving wheel at the meshing point, represents the dimensionless parameter on the meshing line, represents the pitch diameter of the driving wheel, represents the pressure angle.

[0198] The radius of curvature of the driven wheel at the meshing point can be calculated by Equation (29) below:

[0199] (29);

[0200] In the formula, represents the transmission ratio, which is equal to the ratio of the number of teeth of the driving wheel to the number of teeth of the driven wheel.

[0201] Further, when at the tangent point of the meshing line and the base circle of the driving wheel, the dimensionless parameter is equal to 1.

[0202] Further, at the lower bound point of the contact locus, the lower bound point of the contact locus is the lowest point on the tooth surface contact locus, that is, the position where the tooth surface starts to contact during the meshing process, and the dimensionless parameter can be calculated by Equation (30) below:

[0203] (30);

[0204] In the formula, represents the number of teeth of the driving wheel, represents the number of teeth of the driven wheel, represents the addendum circle pressure angle of the driven wheel, represents the pressure angle.

[0205] Among them, It can be calculated by Equation 31 as follows:

[0206] (31);

[0207] Furthermore, at the upper bound point of the contact locus, the upper bound point of the contact locus is the highest point on the tooth surface contact locus, that is, the position where the tooth surface contact ends during the meshing process. The dimensionless parameter It can be calculated by Equation 32 as follows:

[0208] (32);

[0209] In the formula, represents the addendum circle pressure angle of the driving gear, represents the pressure angle.

[0210] Among them, It can be calculated by Equation 33 as follows:

[0211] (33);

[0212] In the formula, represents the addendum circle diameter, represents the pitch circle diameter of the driving gear, represents the pressure angle.

[0213] It should be noted that is denoted as the seventh value, is denoted as the eighth value, is denoted as the ninth value, is denoted as the second preset coefficient.

[0214] In this embodiment, since the comprehensive curvature radius determines the characteristics of the tooth surface rolling friction, the larger the curvature radius, the more uniform the contact pressure distribution. By accurately calculating the comprehensive curvature radius, the calculation accuracy of the rolling friction force and the instantaneous efficiency can be improved.

[0215] Figure 4 is a schematic structural diagram of an intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization device provided by an embodiment of the present application. Please refer to Figure 4 , an embodiment of the present application also provides an intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization device 800, which can implement the above-mentioned intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization method. The intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization device 800 includes:

[0216] An acquisition module 801, configured to acquire multiple groups of initial tooth profile modification parameters, where the initial tooth profile modification parameters are used to modify the gears in the NW-type compound planetary gear train;

[0217] A calculation module 802, configured to calculate according to multiple groups of the initial tooth profile modification parameters to obtain the fitness value of each group of the initial tooth profile modification parameters, where the fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters;

[0218] An iteration module 803, configured to perform iterative calculation on multiple groups of the initial tooth profile modification parameters through an intelligent optimization algorithm to obtain target tooth profile modification parameters, where the target tooth profile modification parameters are tooth profile modification parameters that meet preset conditions, and the intelligent optimization algorithm includes a multi-objective genetic algorithm, and the preset conditions are used to indicate the transmission efficiency and friction loss of the gear;

[0219] An adjustment module 804, configured to adjust the tooth profile of the gear in the NW-type compound planetary gear train by using the target tooth profile modification parameters.

[0220] In some embodiments, the calculation module 802 includes:

[0221] A first calculation sub-module, configured to calculate each group of the initial tooth profile modification parameters through a rolling friction force calculation equation to obtain the friction loss of each group of the tooth profile modification parameters, where the rolling friction force calculation equation is used to calculate the friction loss of the gear;

[0222] A second calculation sub-module, configured to calculate each group of the initial tooth profile modification parameters through an instantaneous transmission efficiency calculation equation to obtain the transmission efficiency of each group of the tooth profile modification parameters, where the instantaneous transmission efficiency calculation equation is used to calculate the transmission efficiency of the gear;

[0223] A third calculation sub-module, configured to obtain the fitness value of each group of the initial tooth profile modification parameters according to the friction loss and transmission efficiency of each group of the tooth profile modification parameters.

[0224] In some embodiments, the NW-type compound planetary gear train includes a driving wheel and a driven wheel;

[0225] The rolling friction force calculation equation is constructed according to a rolling friction coefficient and a load force, and the load force is determined according to the load distribution of the NW-type compound planetary gear train;

[0226] Wherein, the rolling friction coefficient is calculated according to the following steps:

[0227] Calculate according to the geometric parameters of the driving wheel and the geometric parameters of the driven wheel to obtain a recovery coefficient, where the recovery coefficient is used to characterize the ability of the material of the gear to return to its original state after being deformed by force;

[0228] Calculations are performed based on the load force, the comprehensive radius of curvature, the recovery coefficient, the axial length of the cylinder, and the pressure angle to obtain an elastic hysteresis coefficient. The comprehensive radius of curvature is determined based on the radius of curvature of the driving wheel and the radius of curvature of the driven wheel. The elastic hysteresis coefficient is used to characterize the delay phenomenon when the gear returns to its original state after being deformed by force.

[0229] Calculations are performed based on the recovery coefficient, the elastic hysteresis coefficient, the comprehensive radius of curvature, and the axial length of the cylinder to obtain the rolling friction coefficient.

[0230] In some embodiments, the geometric parameters of the driving wheel include the elastic modulus of the driving wheel and the Poisson's ratio of the driving wheel, and the geometric parameters of the driven wheel include the elastic modulus of the driven wheel and the Poisson's ratio of the driven wheel.

[0231] The calculation of the recovery coefficient based on the geometric parameters of the driving wheel and the geometric parameters of the driven wheel includes:

[0232] Taking the ratio of the elastic modulus of the driving wheel to the Poisson's ratio of the driving wheel as a first value;

[0233] Taking the ratio of the elastic modulus of the driven wheel to the Poisson's ratio of the driven wheel as a second value;

[0234] Taking the sum of the first value and the second value as a third value;

[0235] Obtaining the recovery coefficient based on the product of the third value and a preset first coefficient.

[0236] In some embodiments, the calculation of the elastic hysteresis coefficient based on the load force, the comprehensive radius of curvature, the recovery coefficient, the axial length of the cylinder, and the pressure angle includes:

[0237] Taking the ratio of the tangent value of the pressure angle to the recovery coefficient as a fourth value;

[0238] Taking the product of the comprehensive radius of curvature and the axial length of the cylinder as a fifth value;

[0239] Taking the ratio of the fifth value to the load force as a sixth value;

[0240] Calculating the elastic hysteresis coefficient based on the fourth value and the sixth value.

[0241] In some embodiments, the instantaneous transmission efficiency calculation equation is obtained according to the following steps:

[0242] Based on the output power and the input power of the NW-type compound planetary gear train, an initial instantaneous transmission efficiency calculation equation is constructed;

[0243] Adjust the initial instantaneous transmission efficiency calculation equation according to the single and double tooth alternating meshing phenomenon during the operation of the NW-type compound planetary gear train and the rolling friction coefficient to obtain the instantaneous transmission efficiency calculation equation.

[0244] In some embodiments, the comprehensive radius of curvature is calculated according to the following steps:

[0245] Take the product of the rolling angle of the driving wheel and the pitch diameter of the driving wheel as the seventh value;

[0246] Multiply the second preset coefficient by the first value to obtain the radius of curvature of the driving wheel;

[0247] Take the product of the rolling angle of the driven wheel and the pitch diameter of the driven wheel as the eighth value;

[0248] Take the ratio of the number of teeth of the driving wheel to the number of teeth of the driven wheel as the ninth value;

[0249] Take the difference between the ninth value and the second preset coefficient as the tenth value;

[0250] Multiply the eighth value by the tenth value to obtain the radius of curvature of the driven wheel;

[0251] Add the reciprocal of the radius of curvature of the driving wheel to the reciprocal of the radius of curvature of the driven wheel to obtain the comprehensive radius of curvature.

[0252] The specific implementation manner of the NW-type compound planetary gear train transmission efficiency optimization device 800 based on intelligent optimization is basically the same as the specific embodiment of the above-mentioned NW-type compound planetary gear train transmission efficiency optimization method based on intelligent optimization, and will not be elaborated here.

[0253] The embodiment of the present application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the above-mentioned NW-type compound planetary gear train transmission efficiency optimization method based on intelligent optimization. The electronic device can be any intelligent terminal including a desktop computer, a tablet computer, a mobile phone, and a vehicle-mounted computer, etc.

[0254] Please refer to Figure 5 , Figure 5 , which is the hardware structure schematic diagram of the electronic device provided by the embodiment of the present application. The electronic device includes:

[0255] The processor 901 can be implemented in the form of a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application;

[0256] The memory 902 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM), etc. The memory 902 can store an operating system and other application programs. When implementing the technical solutions provided in the embodiments of this specification through software or firmware, the relevant program codes are stored in the memory 902 and are called by the processor 901 to execute the intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization method in the embodiments of the present application;

[0257] The input / output interface 903 is used to implement information input and output;

[0258] The communication interface 904 is used to implement communication interaction between this device and other devices, and can communicate through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.);

[0259] The bus 905 transmits information between various components of the device (such as the processor 901, the memory 902, the input / output interface 903, and the communication interface 904);

[0260] Among them, the processor 901, the memory 902, the input / output interface 903, and the communication interface 904 are communicatively connected to each other inside the device through the bus 905.

[0261] The embodiments of the present application also provide a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization method is implemented.

[0262] As a non-transitory computer-readable storage medium, the memory can be used to store non-transitory software programs and non-transitory computer-executable programs. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory may optionally include a memory remotely disposed relative to the processor, and these remote memories can be connected to the processor through a network. Examples of the above networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0263] The method for optimizing the transmission efficiency of the NW-type compound planetary gear train based on intelligent optimization provided by the embodiments of the present application includes obtaining multiple groups of initial tooth profile modification parameters, calculating the fitness value of each group of initial tooth profile modification parameters, comprehensively considering the transmission efficiency and friction loss of each group of initial tooth profile modification parameters through the fitness value, performing iterative calculations on multiple groups of initial tooth profile modification parameters through an intelligent optimization algorithm until a preset condition is met, stopping the iteration to obtain the target tooth profile modification parameters, determining the optimal solution when the tooth profile modification parameters take into account both transmission efficiency and friction loss through the intelligent optimization algorithm, and adjusting the profiles of the gears in the NW-type compound planetary gear train through the target tooth profile modification parameters to obtain an NW-type compound planetary gear train with better transmission efficiency.

[0264] The embodiments described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art will know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0265] Those skilled in the art can understand that the technical solutions shown in the figures do not limit the embodiments of the present application, and may include more or fewer steps than those shown, or combine certain steps, or different steps.

[0266] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0267] Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices can be implemented as software, firmware, hardware, and appropriate combinations thereof.

[0268] In the description of the present application and the above-mentioned accompanying drawings, terms such as "first", "second", "third", "fourth", etc. (if any) are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0269] It should be understood that in the present application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may mean: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally means that the associated objects before and after are in an "or" relationship. "At least one (one) of the following" or similar expressions refer to any combination of these items, including any combination of single items (ones) or plural items (ones). For example, at least one (one) of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or plural.

[0270] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the above-mentioned division of units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces, and the indirect coupling or communication connection of devices or units can be in electrical, mechanical or other forms.

[0271] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0272] In addition, in each embodiment of the present application, each functional unit may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0273] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product. The computer software product is stored in a storage medium and includes multiple instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in the various embodiments of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs that can store programs.

[0274] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings, and thus do not limit the scope of the rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the rights of the embodiments of the present application.

Claims

1. An optimization method for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization, characterized in that, The method includes: Obtaining multiple groups of initial tooth profile modification parameters, which are used to modify the gears in the NW-type compound planetary gear train; Calculating according to the multiple groups of the initial tooth profile modification parameters to obtain the fitness value of each group of the initial tooth profile modification parameters, and the fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters; Performing iterative calculation on the multiple groups of the initial tooth profile modification parameters through the fitness values corresponding to the multiple groups of the initial tooth profile modification parameters and an intelligent optimization algorithm to obtain target tooth profile modification parameters. The target tooth profile modification parameters are tooth profile modification parameters that meet preset conditions. The intelligent optimization algorithm includes a multi-objective genetic algorithm. The preset conditions are used to indicate the transmission efficiency and friction loss of the gears. Among them, the iterative optimization process of the multi-objective genetic algorithm is as follows: Obtain multiple groups of the initial tooth profile modification parameters as the initial population, and each group of the initial tooth profile modification parameters is used as an individual; Calculate the fitness value of each group of the initial tooth profile modification parameters; Sort the individuals in the initial population according to the Pareto dominance relationship to determine non-dominated solution sets of different levels, and divide the individuals in the initial population into different fronts in the non-dominated solution sets. The first front contains all non-dominated solutions; Calculate the crowding degree of the individuals in each front; Use the binary tournament selection method to select parent individuals, and generate a new generation of solutions through simulated binary crossover and polynomial mutation; If the objective function converges to a stable Pareto solution set, output the target tooth profile modification parameters; Adjusting the tooth profile of the gears in the NW-type compound planetary gear train by using the target tooth profile modification parameters.

2. The method according to claim 1, characterized in that The calculating according to the multiple groups of the initial tooth profile modification parameters to obtain the fitness value of each group of the initial tooth profile modification parameters includes: Calculating each group of the initial tooth profile modification parameters through a rolling friction force calculation equation to obtain the friction loss of each group of the tooth profile modification parameters. The rolling friction force calculation equation is used to calculate the friction loss of the gears; Calculating each group of the initial tooth profile modification parameters through an instantaneous transmission efficiency calculation equation to obtain the transmission efficiency of each group of the tooth profile modification parameters. The instantaneous transmission efficiency calculation equation is used to calculate the transmission efficiency of the gears; Obtaining the fitness value of each group of the initial tooth profile modification parameters according to the friction loss and transmission efficiency of each group of the tooth profile modification parameters.

3. The method according to claim 2, wherein The NW-type compound planetary gear train includes a driving wheel and a driven wheel; The rolling friction force calculation equation is constructed according to the rolling friction coefficient and the load force, and the load force is determined according to the load distribution of the NW-type compound planetary gear train; Among them, the rolling friction coefficient is calculated according to the following steps: Calculating according to the geometric parameters of the driving wheel and the geometric parameters of the driven wheel to obtain a recovery coefficient, and the recovery coefficient is used to characterize the ability of the gear material to return to its original state after being deformed by force; Calculations are performed based on the load force, the comprehensive radius of curvature, the restitution coefficient, the axial length of the cylinder, and the pressure angle to obtain the elastic hysteresis coefficient. The comprehensive radius of curvature is determined according to the radius of curvature of the driving wheel and the radius of curvature of the driven wheel. The elastic hysteresis coefficient is used to characterize the delay phenomenon when the gear returns to its original state after being deformed by force. Calculations are performed based on the restitution coefficient, the elastic hysteresis coefficient, the comprehensive radius of curvature, and the axial length of the cylinder to obtain the rolling friction coefficient.

4. The method according to claim 3, characterized in that The geometric parameters of the driving wheel include the elastic modulus of the driving wheel and the Poisson's ratio of the driving wheel. The geometric parameters of the driven wheel include the elastic modulus of the driven wheel and the Poisson's ratio of the driven wheel. The calculation of the restitution coefficient based on the geometric parameters of the driving wheel and the geometric parameters of the driven wheel includes: Taking the ratio of the elastic modulus of the driving wheel to the Poisson's ratio of the driving wheel as the first value; Taking the ratio of the elastic modulus of the driven wheel to the Poisson's ratio of the driven wheel as the second value; Taking the sum of the first value and the second value as the third value; Obtaining the restitution coefficient according to the product of the third value and a preset first coefficient.

5. The method according to claim 3, wherein The calculation of the elastic hysteresis coefficient based on the load force, the comprehensive radius of curvature, the restitution coefficient, the axial length of the cylinder, and the pressure angle includes: Taking the ratio of the tangent function of the pressure angle to the restitution coefficient as the fourth value; Taking the product of the comprehensive radius of curvature and the axial length of the cylinder as the fifth value; Taking the ratio of the fifth value to the load force as the sixth value; Calculating the elastic hysteresis coefficient according to the fourth value and the sixth value.

6. The method according to claim 3, characterized in that The instantaneous transmission efficiency calculation equation is obtained according to the following steps: Constructing an initial instantaneous transmission efficiency calculation equation based on the output power and input power of the NW-type compound planetary gear train; Adjusting the initial instantaneous transmission efficiency calculation equation according to the single-double tooth alternating meshing phenomenon during the operation of the NW-type compound planetary gear train and the rolling friction coefficient to obtain the instantaneous transmission efficiency calculation equation.

7. The method according to claim 3, wherein The comprehensive radius of curvature is calculated according to the following steps: Taking the product of the pressure angle and the pitch diameter of the driving wheel as the seventh value; Multiplying the second preset coefficient by the seventh value to obtain the radius of curvature of the driving wheel; Taking the ratio of the number of teeth of the driving wheel to the number of teeth of the driven wheel as the eighth value; Taking the difference between the eighth value and the second preset coefficient as the ninth value; Multiplying the seventh value by the ninth value to obtain the radius of curvature of the driven wheel; Adding the reciprocal of the radius of curvature of the driving wheel and the reciprocal of the radius of curvature of the driven wheel to obtain the comprehensive radius of curvature.

8. An optimization device for the transmission efficiency of an NW-type compound planetary gear train based on intelligent optimization, characterized in that, The device includes: An acquisition module for acquiring multiple groups of initial tooth profile modification parameters, which are used to modify the gears in the NW-type compound planetary gear train; A calculation module for calculating, according to multiple groups of the initial tooth profile modification parameters, the fitness value of each group of the initial tooth profile modification parameters, where the fitness value is used to characterize the quality of the corresponding initial tooth profile modification parameters. An iterative module, configured to perform iterative calculations on multiple groups of the initial tooth profile modification parameters through the fitness values corresponding to the multiple groups of the initial tooth profile modification parameters and an intelligent optimization algorithm to obtain target tooth profile modification parameters, where the target tooth profile modification parameters are tooth profile modification parameters that meet preset conditions, the intelligent optimization algorithm includes a multi-objective genetic algorithm, and the preset conditions are used to indicate the transmission efficiency and frictional loss of the gear. Among them, the iterative optimization process of the multi-objective genetic algorithm is as follows: Obtain multiple groups of the initial tooth profile modification parameters as the initial population, and each group of the initial tooth profile modification parameters serves as an individual; Calculate the fitness value of each group of the initial tooth profile modification parameters; Sort the individuals in the initial population according to the Pareto dominance relationship to determine non-dominated solution sets of different levels, and divide the individuals in the initial population into different fronts in the non-dominated solution sets, where the first front contains all non-dominated solutions; Calculate the crowding degree of the individuals in each front; Select parent individuals using the binary tournament selection method and generate a new generation of solutions through simulated binary crossover and polynomial mutation; If the objective function converges to a stable Pareto solution set, output the target tooth profile modification parameters; An adjustment module, configured to adjust the tooth profile of the gears in the NW-type compound planetary gear train by using the target tooth profile modification parameters.

9. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it implements the intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the intelligent optimization-based NW-type compound planetary gear train transmission efficiency optimization method according to any one of claims 1 to 7.

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