Method for optimizing electromagnetic force characteristics of proportional electromagnet for power shifting transmission of cotton picker

Abstract

The invention provides a method for optimizing electromagnetic force characteristics of a proportion electromagnet for a cotton picker power gear-shifting transmission by researching the proportion electromagnet for the cotton picker power gear-shifting transmission. The method comprises the steps that firstly, a proportion electromagnet finite element model is constructed, static simulation analysis is conducted on a proportion electromagnet, and parameterized control and automatic simulation of a proportion electromagnet model are achieved by constructing an Isight and Maxwell joint simulation model; then selecting a proportion electromagnet optimization variable according to the structural characteristics of the proportion electromagnet, sampling sample points by adopting an optimal Latin hypercube test design method, constructing an agent model, carrying out fitting precision verification, replacing an actual model with the agent model to carry out simulation analysis, and determining a constraint condition and an optimization target; and then, optimizing the key parameters of the proportion electromagnet by adopting a multi-island genetic algorithm, and finally, verifying the optimized parameters to obtain a final result of structure optimization of the proportion electromagnet. According to the method for optimizing the electromagnetic force characteristics of the proportion electromagnet for the cotton picker power gear shifting transmission, the displacement-electromagnetic force horizontal characteristics of the proportion electromagnet can be obviously improved, and the method is of great significance to gear shifting accurate control and stable operation of a cotton picker power gear shifting system.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of proportional electromagnet electromagnetic force characteristics optimization method, especially to a kind of proportional electromagnet electromagnetic force characteristics optimization method for power shift transmission of cotton picker. BACKGROUND

[0002] In modern agricultural mechanization operation, cotton picker as the key equipment of cotton harvesting, it not only improves the harvesting efficiency of cotton, also directly affects the harvesting quality of cotton. The shift performance of cotton picker is the key indicator to measure its operation effect. Proportional electromagnet as a precise and adjustable electrical-mechanical conversion device, it occupies the core position in the shift control system of power shift transmission of cotton picker, it adjusts shift hydraulic system by accurately controlling electromagnetic force, ensures the smoothness and accuracy of shift process, which is crucial for improving the operating efficiency of cotton picker and the harvesting quality of cotton. Since the electromagnetic force characteristics of proportional electromagnet are influenced by many factors, many studies focus on single or partial indicators, resulting in unstable electromagnetic force output and response delay in actual work, and the research is missing in the specific application scenarios such as power shift transmission of cotton picker, therefore, by optimizing the electromagnetic force characteristics of proportional electromagnet for power shift transmission of cotton picker, improving its control precision and reliability, it is of great significance to further improve the shift quality of cotton picker. SUMMARY

[0003] To overcome the limitations of the existing proportional electromagnet electromagnetic force characteristics optimization in the above background art and the problem of missing research in specific application scenarios such as power shift transmission of cotton picker, the present application provides a proportional electromagnet electromagnetic force characteristics optimization method for power shift transmission of cotton picker.

[0004] To achieve the above purpose, the present application adopts the following technical solutions:

[0005] The proportional electromagnet electromagnetic force characteristics optimization method for power shift transmission of cotton picker of the present application, the proportional electromagnet is mainly composed of rear yoke 1, coil skeleton 2, coil 3, front yoke 4, shell 5 and armature 6; the specific steps of proportional electromagnet electromagnetic force characteristics optimization method are as follows:

[0006] Step 1: Establishing finite element model of proportional electromagnet;

[0007] Step 2: Static simulation analysis of proportional electromagnet;

[0008] Step 3: Joint simulation of Isight and Maxwell;

[0009] Step 4: Selecting optimization variables of proportional electromagnet;

[0010] Step 5: Optimal Latin hypercube design;

[0011] Step 6: Proxy model establishment and fitting precision detection;

[0012] Step 7: Constraint condition and optimization target establishment;

[0013] Step 8: Multi-island genetic algorithm is used to optimize key parameters of proportional electromagnet;

[0014] Step 9: The final optimized solution is obtained through verification of optimized parameters.

[0015] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the power shift transmission of the cotton picker is characterized in that the proportional electromagnet finite element model establishment and the proportional electromagnet static simulation analysis are both performed in the Ansys Maxwell software, and in the simulation process, the core mathematical model relied on is the Maxwell equation group, and in view of the axial symmetry of the structure of the proportional electromagnet, the finite element simulation model of 1 / 4 proportional electromagnet is constructed according to the Z-axis symmetry characteristic.

[0016] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the power shift transmission of the cotton picker is characterized in that: in step 3, Isight and Maxwell are simulated jointly, this step utilizes the integrated advantages of Isight platform and Maxwell software to realize parameterized control and automatic simulation of the proportional electromagnet model. The design parameters are automatically modified by Isight to drive Maxwell to perform simulation calculation, and the results are processed. This method can systematically study the influence of multi-parameter coupling, and improve the optimization efficiency and comprehensiveness.

[0017] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the power shift transmission of the cotton picker is characterized in that: in step 4, proportional electromagnet optimization variable selection, according to the working principle of the proportional electromagnet, combined with actual engineering demand and manufacturing process, the design parameters which have significant influence on the electromagnetic force characteristic of the proportional electromagnet are selected as optimization variables.

[0018] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the power shift transmission of the cotton picker is characterized in that: in step 5, optimal Latin hypercube experimental design, this step adopts the optimal Latin hypercube experimental design method to uniformly select sample points in the value range of the optimization variables. By dividing the variable interval and uniformly sampling, sample aggregation is avoided, and representative data is obtained with fewer test times.

[0019] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the cotton picker power shift transmission is characterized in that: in the step 6, the agent model is established and the fitting accuracy is detected. 2 The fitting accuracy of the agent model and the actual sample points is detected by using the error analysis method.

[0020] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the cotton picker power shift transmission is characterized in that: in the step 7, the constraint condition and the optimization target are established, and in this step, the constraint condition of the proportional electromagnet optimization is established according to the actual design requirement, and the optimization target is also determined.

[0021] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the cotton picker power shift transmission is characterized in that: in the step 8, the multi-island genetic algorithm is used to optimize the key parameters of the proportional electromagnet, and in this step, the multi-island genetic algorithm is used to perform global search on the agent model. The population is divided into multiple sub-populations for parallel evolution, and the individuals are optimized through selection, crossover and mutation operations, and the individuals between islands are migrated. The agent model is used as the fitness function, and the optimal solution is output through iterative search. The optimization parameters of the multi-island genetic algorithm are set as follows: the sub-population size is set to 30, the island number is set to 10, the generation number is set to 5, the crossover rate is set to 0.9, the mutation rate is set to 0.01, the migration rate is set to 0.01, the migration interval is set to 5, and the elite size is set to 1.

[0022] Preferably, the proportional electromagnet electromagnetic force characteristic optimization method for the cotton picker power shift transmission is characterized in that: in the step 9, the final optimization solution is obtained by verifying the optimization parameters, and in this step, the optimization parameters are substituted into the finite element model for simulation verification, the electromagnetic force characteristics before and after optimization are compared, and whether the constraint condition is met is detected.

[0023] The beneficial effects of the present application are as follows:

[0024] The proportional electromagnet electromagnetic force characteristic optimization method for the cotton picker power shift transmission can effectively overcome the problem of the lack of research on the proportional electromagnet in the specific application scenario of the cotton picker power shift transmission in the prior art, can obviously improve the displacement-electromagnetic force level characteristic of the proportional electromagnet, and has important significance for realizing the shift accurate control and smooth operation of the cotton picker power shift system. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The optimization method flow of the present application is shown in the figure;

[0026] Figure 2 The two-dimensional simulation model of the proportional electromagnet of the present application is shown in the figure;

[0027] Figure 3 Static simulation process of the proportional electromagnet of the application;

[0028] Figure 4 Optimization parameter of the proportional electromagnet of the application;

[0029] Figure 5 Optimization flow chart of the multi-island genetic algorithm of the application;

[0030] Figure 6 Proportional electromagnet displacement-magnetic force curve comparison chart before and after optimization of the application.

[0031] The figure label: 1 - rear yoke; 2 - coil skeleton; 3 - coil; 4 - front yoke; 5 - shell; 6 - armature. DETAILED DESCRIPTION

[0032] The application will be described in detail below in combination with the drawings and specific examples.

[0033] The proportional electromagnet electromagnetic force characteristic optimization method for the power gear shifting transmission of the cotton picker has the characteristics that the proportional electromagnet is mainly composed of a rear yoke 1, a coil skeleton 2, a coil 3, a front yoke 4, a shell 5 and an armature 6; and the specific steps of the proportional electromagnet electromagnetic force characteristic optimization method are as follows:

[0034] Step 1: proportional electromagnet finite element model establishment;

[0035] Step 2: proportional electromagnet static simulation analysis;

[0036] Step 3: Isight and Maxwell joint simulation;

[0037] Step 4: proportional electromagnet optimization variable selection;

[0038] Step 5: optimal Latin hypercube experimental design;

[0039] Step 6: proxy model establishment and fitting precision detection;

[0040] Step 7: constraint condition and optimization target establishment;

[0041] Step 8: multi-island genetic algorithm is adopted to optimize the key parameters of the proportional electromagnet;

[0042] Step 9: optimization parameter verification to obtain the final optimization solution.

[0043] The proportional electromagnet electromagnetic force characteristic optimization method for the power gear shifting transmission of the cotton picker has the characteristics that the proportional electromagnet finite element model establishment and the proportional electromagnet static simulation analysis are both carried out in the Ansys Maxwell software, Figure 2A two-dimensional simulation model of the proportional electromagnet, Figure 3 For the static simulation process of the proportional electromagnet, the core mathematical model relied on in the simulation process is the Maxwell equation set. In view of the fact that the structure of the proportional electromagnet has axial symmetry, a finite element simulation model of 1 / 4 of the proportional electromagnet is constructed according to the Z-axis symmetry characteristic. The materials of each part of the proportional electromagnet, such as the rear yoke, the coil skeleton, the coil, the front yoke, the shell and the armature, are set in the Ansys Maxwell software according to the material characteristics of each part.

[0044] The method for optimizing the electromagnetic force characteristics of the proportional electromagnet for the power shift transmission of the cotton picker, characterized in that step 3 is the joint simulation of Isight and Maxwell, which utilizes the integrated advantages of the Isight platform and the Maxwell software to realize the parameterized control and automatic simulation of the proportional electromagnet model. The design parameters are automatically modified by Isight to drive Maxwell to perform simulation calculation, and the results are processed. This method can systematically study the influence of multiple parameter coupling and avoid the limitations of traditional single-parameter optimization methods, so as to more comprehensively optimize the electromagnetic force characteristics of the proportional electromagnet and further improve the optimization efficiency and comprehensiveness.

[0045] The method for optimizing the electromagnetic force characteristics of the proportional electromagnet for the power shift transmission of the cotton picker, characterized in that step 4 is the selection of the optimization variables of the proportional electromagnet, which selects the design parameters that have a significant influence on the electromagnetic force characteristics of the proportional electromagnet as optimization variables according to the working principle of the proportional electromagnet and in combination with the actual engineering requirements and manufacturing processes, Figure 4 For the optimization parameters of the proportional electromagnet, the changes of these variables will directly affect the magnetic field distribution and electromagnetic force size inside the proportional electromagnet. By reasonably selecting the optimization variables, the optimization difficulty and cost can be reduced while ensuring the optimization effect. The specific mathematical model of the optimization variables of the proportional electromagnet can be expressed as:

[0046] Optimization variables:

[0047] The method for optimizing the electromagnetic force characteristics of the proportional electromagnet for the power shift transmission of the cotton picker, characterized in that step 5 is the optimal Latin hypercube experimental design, which adopts the optimal Latin hypercube experimental design method to uniformly select sample points within the value range of the optimization variables. By dividing the variable interval and uniformly sampling, the local bias caused by the concentration of sample points can be reduced, thereby improving the efficiency of the experiment and the reliability of the results.

[0048] The method for optimizing the electromagnetic force characteristics of the proportional electromagnet of the cotton picker power shift transmission is characterized in that step 6, the proxy model is established and the fitting accuracy is detected, the proxy model uses the RBF neural network model built in Isight, and the relationship between the input variables and the output response of the proxy model is:

[0049]

[0050] In the formula, y(x) is an actual value of a response, an unknown function; is an approximate value of the response, a known polynomial; and epsilon is an error between the actual value and the approximate value.

[0051] The RBF neural network model is used to establish the proxy model. 2 An error analysis method is used to test the fitting accuracy of the proxy model and the actual sample points, and when R 2 is greater than 0.9, it is indicated that the fitting accuracy is high enough, and the prediction model can be used to replace the actual model for simulation.

[0052] The method for optimizing the electromagnetic force characteristics of the proportional electromagnet of the cotton picker power shift transmission is characterized in that step 7, the constraint condition and the optimization target are established, the constraint condition of the proportional electromagnet optimization is established according to the actual design requirement, and the optimization target is also determined, and the specific mathematical model of the constraint condition and the optimization target of the proportional electromagnet optimization can be expressed as:

[0053] The constraint condition is s.t.: -32 <= F0, F1, F2, F3 <= 30.

[0054] The optimization target is obj: Min(F0, F1, F2, F3).

[0055] In the formula, F0, F1, F2 and F3 are electromagnetic forces of the proportional electromagnet armature displacement at 0 um, 100 um, 250 um and 400 um.

[0056] The method for optimizing the electromagnetic force characteristics of the proportional electromagnet of the cotton picker power shift transmission is characterized in that step 8, the multi-island genetic algorithm is used to optimize the key parameters of the proportional electromagnet, the multi-island genetic algorithm is used to perform global search on the proxy model, the population is divided into multiple sub-populations for parallel evolution, the individuals are optimized through selection, crossover and mutation operations, and the individuals are migrated between islands. The proxy model is used as the fitness function, and the optimal solution is output through iterative search. The optimization setting parameters of the multi-island genetic algorithm are as follows: the sub-population size is set to 30, the island number is set to 10, the generation number is set to 5, the crossover rate is set to 0.9, the mutation rate is set to 0.01, the migration rate is set to 0.01, the migration interval is set to 5, the elite size is set to 1, and the multi-island genetic algorithm flowchart is as shown in Figure 5 .

[0057] The method for optimizing the electromagnetic force characteristics of the proportional electromagnet of the cotton picker power shift transmission is characterized in that: in step 9, the final optimization solution is obtained by verifying the optimization parameters, and in this step, the optimization parameters are substituted into the finite element model for simulation verification, and the electromagnetic force characteristics before and after optimization are compared. Figure 6 As shown in the figure, within the working stroke of the proportional electromagnet, the average electromagnetic force is increased from 29.49 N to 30.24 N, and the average electromagnetic force is increased by 2.54%. In order to more accurately quantify this difference, the electromagnetic force is calculated by using the variance formula, and the variance formula is:

[0058]

[0059] In the formula, S 2 is the sample variance; n is the sample size; x j is the value of the jth data point; and is the sample mean.

[0060] The calculation results show that the electromagnetic force variance of the proportional electromagnet before optimization is 2.31, and the electromagnetic force variance of the proportional electromagnet after optimization is reduced to 0.38, and the electromagnetic force variance is significantly reduced, and the degree of dispersion is reduced. The horizontal characteristics of the displacement-electromagnetic force curve of the proportional electromagnet are obviously improved, and the stability of the electromagnetic force is obviously improved.

[0061] The present application mainly proposes a method for optimizing the electromagnetic force characteristics of the proportional electromagnet of the cotton picker power shift transmission, which effectively overcomes the problem of lack of research on the proportional electromagnet in the specific application scenario of the cotton picker power shift transmission in the prior art, and can obviously improve the horizontal characteristics of the displacement-electromagnetic force of the proportional electromagnet. It is of great significance to realize the accurate control and smooth operation of the shift system of the cotton picker power shift transmission. The method for optimizing the electromagnetic force characteristics of the proportional electromagnet of the cotton picker power shift transmission proposed in the present application is not only suitable for the proportional electromagnet of the cotton picker power shift transmission, but also suitable for other proportional electromagnets of the same type.

[0062] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A method for optimizing electromagnetic force characteristics of a proportional electromagnet for a power shift transmission of a cotton picker, characterized by: The proportional electromagnet is mainly composed of a rear magnetic yoke (1), a coil frame (2), a coil (3), a front magnetic yoke (4), a housing (5), and an armature (6). The specific steps of the method for optimizing the electromagnetic force characteristics of the proportional electromagnet are as follows: Step 1: Establishment of finite element model of proportional electromagnet; Step 2: Static simulation analysis of proportional solenoid; Step 3: Joint simulation of Isight and Maxwell; Step 4: Select the optimized variables of proportional solenoid; Step 5: Optimal Latin hypercube experimental design; Step 6: Establishing the surrogate model and testing the fitting accuracy; Step 7: Establish constraints and optimization objectives; Step 8: Use multi-island genetic algorithm to optimize the key parameters of the proportional electromagnet; Step 9: Verify the optimization parameters to obtain the final optimization solution.

2. The method for optimizing electromagnetic force characteristics of a proportional electromagnet for a power shift transmission of a cotton picker according to claim 1, characterized in that: The establishment of the proportional electromagnet finite element model and the static simulation analysis of the proportional electromagnet are both performed in Ansys Maxwell software. During the simulation process, the core mathematical model relied on is the Maxwell equations.

3. The method for optimizing electromagnetic force characteristics of a proportional electromagnet for a power shift transmission of a cotton picker according to claim 1, characterized in that: The specific mathematical model of proportional electromagnet optimization variables, constraints and optimization objectives is: Optimize variable: var: Constraints: st: -32≤F0,F1,F2,F3≤30 Optimization objective: obj:Min(F0,F1,F2,F3).

4. The method for optimizing electromagnetic force characteristics of a proportional electromagnet for a power shift transmission of a cotton picker according to claim 1, characterized in that: The establishment of the proxy model and the fitting accuracy test are carried out in the software Isight. The proxy model uses the RBF neural network model built into Isight and adopts R 2 Error analysis method is used to test the fitting accuracy of the proxy model and the actual sample points.

5. The method for optimizing electromagnetic force characteristics of a proportional electromagnet for a power shift transmission of a cotton picker according to claim 1, characterized in that: The multi-island genetic algorithm is used to perform a global search for the agent model. The optimization setting parameters of the multi-island genetic algorithm are as follows: subpopulation size is set to 30, the number of islands is set to 10, the number of generations is set to 5, the crossover rate is set to 0.9, the mutation rate is set to 0.01, the migration rate is set to 0.01, the migration interval is set to 5, and the elite size is set to 1.

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