Synchronizer parameter multi-objective optimization method based on NSGA (II)-PSO

Abstract

The invention discloses a synchronizer parameter multi-objective optimization method based on NSGA (II)-PSO, and the method comprises the following steps: S1, building a gear shifting process dynamical model based on gear shifting system analysis; s2, selecting the gear shifting time, the maximum inter-tooth impact degree and the sliding friction work as gear shifting performance evaluation indexes, and selecting the gear shifting motor rated power as an economic performance evaluation index; s3, analyzing influence rules of different structure parameters and control parameters on gear shifting performance and economic performance, exploring influence degrees of the parameters on evaluation indexes, and determining optimization variables; s4, the gear shifting performance and the economic performance serve as optimization objectives, normalization processing is conducted on the optimization objectives, constraint conditions of objective functions and optimization variables are determined, and multi-objective optimization is conducted on the structure parameters and the control parameters through an NSGA (II)-PSO optimization algorithm. The gear shifting performance and the economic performance are comprehensively considered, the effective method suitable for forward optimization design of the synchronizer is provided, optimization of parameters of the synchronizer is achieved, and the overall performance of the synchronizer is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of synchronizers, and in particular to a synchronizer parameter multi-objective optimization method based on NSGA(II)-PSO. Background Art

[0002] The synchronizer is a key component of the automobile transmission. It ensures smooth gear shifting, reduces gear impact, and improves driving comfort and transmission life by synchronizing the speed. The structural parameters and control parameters of the synchronizer have an important impact on the smoothness, rapidity, reliability and economy of gear shifting. Traditional synchronizer parameter optimization methods often use trial and error methods or experience-based adjustment methods. These methods often only focus on a single performance indicator and ignore other equally important performance indicators.

[0003] The above optimization methods often lead to conflicts between shifting performance and economic performance, making it difficult to achieve optimal comprehensive performance. In addition, there are often complex coupling relationships between parameters, and traditional optimization methods often find it difficult to accurately describe these relationships, resulting in inaccurate and unreliable optimization results. Therefore, there is an urgent need for an optimization method that can comprehensively consider multiple performance indicators and accurately describe the relationship between synchronizer parameters. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a synchronizer parameter multi-objective optimization method based on NSGA(Ⅱ)-PSO, which realizes the optimization of synchronizer parameters and effectively improves the overall performance of the synchronizer by combining the advantages of non-dominated sorting genetic algorithm II with elite strategy and particle swarm optimization algorithm.

[0005] In order to achieve the above object, the present invention provides a synchronizer parameter multi-objective optimization method based on NSGA (II)-PSO, comprising the following steps:

[0006] S1: Based on the shifting system analysis, a dynamic model of the shifting process is established;

[0007] S2: Select shifting time, maximum impact between teeth, and sliding friction work as shifting performance evaluation indicators, and rated power of the shifting motor as the economic performance evaluation indicator;

[0008] S3: Analyze the influence of different structural parameters and control parameters on shifting performance and economic performance, use importance analysis to explore the influence of parameters on evaluation indicators, and determine the optimization variables;

[0009] S4: Taking shifting performance and economic performance as optimization objectives, the optimization objectives are normalized, the constraints of the objective function and optimization variables are determined, and the NSGA(II)-PSO optimization algorithm is used to perform multi-objective optimization of the structural parameters and control parameters.

[0010] Furthermore, in step S1, the gear shifting process dynamics model includes a power source model and a gear shifting process model.

[0011] Furthermore, in step S2, the shift time calculation equation is: shift =∑t i ;

[0012] In the formula, t shift is the shift time, t i The time used for each stage of gear shifting;

[0013] The impact degree calculation equation is: max =max(m slv )|v slv (t i+1 )-v slv (t i )|;

[0014] In the formula, I max is the maximum impact between teeth, m slv is the mass of the joint sleeve, v slv is the axial moving speed of the coupling sleeve;

[0015] The sliding friction work calculation equation is:

[0016] Where W s is the friction work, T syn is the synchronous friction torque, Δω is the speed difference;

[0017] The rated power equation of the shift motor is:

[0018] Where P r F is the rated power of the shift motor; shift is the shifting force; R cam is the camshaft rotation radius; a cam is the camshaft rotation angle; μ1 and μ2 are the friction coefficients; x slv is the displacement of the coupling sleeve; η is the transmission efficiency of the reduction mechanism; t is the gear shifting time.

[0019] Furthermore, in step S3, the structural parameters analyzed include the chamfer angle a of the tooth end of the coupling sleeve and the coupling ring gear. gear , Synchronous ring friction cone angle a cone , equivalent input moment of inertia J in , Synchronous ring moment of inertia J syn , the mass of the joint sleeve m slv , Average radius of friction cone surface of synchronizer ring r cone , friction coefficient between the teeth of the coupling sleeve and the coupling ring gear μ slvgr And the friction coefficient μ of the synchronizer ring conecone ;

[0020] Through importance analysis, the friction coefficient μ of the synchronizer ring cone is selected. cone , Average radius of friction cone surface of synchronizer ring r cone , Synchronous ring friction cone angle a cone , chamfer angle a of the tooth end of the coupling sleeve and the coupling ring gear gear , the mass of the joint sleeve m slv and equivalent input moment of inertia J in Optimize; the selected control parameters include shift force F shift and the speed difference Δω.

[0021] Furthermore, in step S4, the selected optimization target is normalized, and the formula is as follows:

[0022]

[0023] In the formula, t shift is the shift time; Q1(t shift ) is the normalized value of the shift time; I max is the maximum impact between teeth; Q2(I max ) is the normalized value of the maximum impact between teeth; W s is the sliding friction work; Q3(W s ) is the normalized value of sliding friction work; P r is the rated power of the shift motor; Q4(P r ) is the normalized value of the rated power of the shift motor;

[0024] The optimization objective function is:

[0025] Q=λ1f(Q1(t shift ), Q2(I max ), Q3(W s ))+λ2Q4(P r );

[0026] In the formula, λ1 is the weight factor of shifting performance; λ2 is the weight factor of economic performance;

[0027] The constraints are:

[0028]

[0029] In the formula, a cone is the friction cone angle of the synchronizer ring, T b is the tooth end locking torque, T syn is the synchronous friction torque, X min is the minimum value of the structural parameter, X is the structural parameter, X max is the maximum value of the structural parameter, Y minis the minimum value of the control parameter, Y is the control parameter, Y max is the maximum value of the control parameter.

[0030] Furthermore, in the optimization stage, the inner layer uses the non-dominated sorting genetic algorithm II with elite strategy to balance the contradictions among shifting time, maximum impact degree between teeth, and sliding friction work, and the outer layer uses the particle swarm optimization algorithm to optimize the shifting performance weight factor and the economic performance weight factor.

[0031] Beneficial effects of the present invention:

[0032] The present invention balances the contradiction between shifting performance and economic performance by optimizing the parameters of the synchronizer, can comprehensively consider multiple performance indicators, and improve the comprehensive performance of the synchronizer; by constructing a combination of a dynamic simulation model and an optimization algorithm, an effective method suitable for the forward optimization design of the synchronizer is provided, and the optimization result is more accurate and reliable, which is helpful to promote the further development and application of the synchronizer technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a flowchart of a synchronizer parameter multi-objective optimization method based on NSGA (II)-PSO.

[0034] Figure 2 It is a line graph showing the influence of the synchronizer structural parameters on the shifting time in the shifting performance evaluation index of the present invention.

[0035] Figure 3 It is a line graph showing the influence of the synchronizer structural parameters on the maximum impact between teeth in the shifting performance evaluation index of the present invention.

[0036] Figure 4 It is a line graph showing the influence of the synchronizer structural parameters on the sliding friction work in the shifting performance evaluation index of the present invention.

[0037] Figure 5 It is a line graph showing the influence of the synchronizer structural parameters on the rated power of the shift motor in the economic performance evaluation index of the present invention.

[0038] Figure 6 This is a bar chart analyzing the importance of the synchronizer structural parameters of the present invention to the shifting performance and economic performance.

[0039] Figure 7 This is a simulation result diagram of the influence of the synchronizer control parameters on the shifting performance and economic performance of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The invention discloses a synchronizer parameter multi-objective optimization method based on NSGA(II)-PSO.

[0042] Reference Figures 1 to 7 , a synchronizer parameter multi-objective optimization method based on NSGA(Ⅱ)-PSO, the method comprises the following steps:

[0043] S1: Based on the analysis of the gear shifting system, a gear shifting process dynamics model is established. The gear shifting process dynamics model includes a power source model and a gear shifting process model.

[0044] S2: The shifting time, the maximum impact between teeth and the sliding friction work are selected as the shifting performance evaluation indicators, and the rated power of the shifting motor is selected as the economic performance evaluation indicator.

[0045] Among them, the shift time refers to the time required for the synchronizer to drive the shift fork from the current gear to the target gear and the power source torque to recover to the target value after the TCU issues a shift command. The formula is as follows:

[0046] t shift =∑t i ;

[0047] In the formula, t shift is the shift time, t i The time taken for each gear shifting stage.

[0048] The impact is generated by the synchronizer during the movement process, mainly in the meshing stage between the clutch and the synchronizer ring, and between the clutch and the clutch gear ring. The greater the meshing speed difference between the teeth and the axial force on the clutch, the greater the impact. Therefore, reasonable control of the action process of the drive motor and the actuator will help reduce the gear shift impact and improve the smoothness and comfort of gear shifting. The formula is as follows:

[0049] I max =max(m slv )|v slv (t i+1 )-v slv (t i )|;

[0050] In the formula, I max is the maximum impact between teeth, m slv is the mass of the joint sleeve, v slvis the axial moving speed of the coupling sleeve.

[0051] Sliding friction work refers to the work generated by friction between the meshing gear ring and the synchronizer ring during synchronization. The greater the sliding friction work, the more severe the wear of the synchronizer friction elements, which seriously affects the service life of the synchronizer. Therefore, reasonably limiting the shift force and speed difference can effectively extend the service life of the synchronizer. The formula is as follows:

[0052]

[0053] Where W s is the friction work, T syn is the synchronous friction torque, and Δω is the speed difference.

[0054] The rated power of the shift motor refers to the maximum power value that can be continuously and stably output under normal working conditions. The formula is as follows:

[0055]

[0056] Where P r F is the rated power of the shift motor; shift is the shifting force; R cam is the camshaft rotation radius; a cam is the camshaft rotation angle; μ1 and μ2 are the friction coefficients; x slv is the displacement of the coupling sleeve; η is the transmission efficiency of the reduction mechanism; t is the gear shifting time.

[0057] S3: Analyze the influence of different structural parameters and control parameters on shifting performance and economic performance, use importance analysis to explore the influence of parameters on evaluation indicators, and determine the optimization variables.

[0058] The structural parameters analyzed include the chamfer angle a of the tooth end of the coupling sleeve and the coupling ring gear. gear , Synchronous ring friction cone angle a cone , equivalent input moment of inertia J in , Synchronous ring moment of inertia J syn , the mass of the joint sleeve m slv , Average radius of friction cone surface of synchronizer ring r cone , friction coefficient between the teeth of the coupling sleeve and the coupling ring gear μ slvgr And the friction coefficient μ of the synchronizer ring cone cone .

[0059] Through importance analysis, the friction coefficient μ of the synchronizer ring cone is selected. cone , Average radius of friction cone surface of synchronizer ring r cone , Synchronous ring friction cone angle a cone , chamfer angle a of the tooth end of the coupling sleeve and the coupling ring gear gear , the mass of the joint sleeve m slv, equivalent input moment of inertia J in The selected control parameters include the shift force F shift And the relative speed difference Δω between the clutch sleeve and the clutch ring gear.

[0060] S4: Taking shifting performance and economic performance as optimization objectives, the optimization objectives are normalized, the constraints of the objective function and optimization variables are determined, and the NSGA(II)-PSO optimization algorithm is used to perform multi-objective optimization of the structural parameters and control parameters.

[0061] In step S4, the selected optimization target is normalized, and the formula is as follows:

[0062]

[0063] In the formula, t shift is the shift time; Q1(t shift ) is the normalized value of the shift time; I max is the maximum impact between teeth; Q2(I max ) is the normalized value of the maximum impact between teeth; W s is the sliding friction work; Q3(W s ) is the normalized value of sliding friction work; P r is the rated power of the shift motor; Q4(P r ) is the normalized value of the rated power of the shift motor.

[0064] The optimization objective function is as follows:

[0065] Q=λ1f(Q1(t shift ), Q2(I max ), Q3(W s ))+λ2Q4(P r );

[0066] Where λ1 is the weight factor of shifting performance; λ2 is the weight factor of economic performance.

[0067] The constraints are as follows:

[0068]

[0069] In the formula, a cone is the friction cone angle of the synchronizer ring, T b is the tooth end locking torque, T syn is the synchronous friction torque, X min is the minimum value of the structural parameter, X is the structural parameter, X max is the maximum value of the structural parameter, Y min is the minimum value of the control parameter, Y is the control parameter, Y max is the maximum value of the control parameter.

[0070] In the optimization stage, the inner layer uses the non-dominated sorting genetic algorithm II (NSGA(II)) with elite strategy to balance the contradictions among the shift time, the maximum impact degree between teeth, and the sliding friction work, and the outer layer uses the particle swarm optimization algorithm (PSO) to optimize the shift performance weight factor and the economic performance weight factor. The NSGA-II algorithm can ensure the diversity and distribution uniformity of the solution set, and its computational efficiency and convergence speed are faster than traditional methods, which is suitable for solving the multi-objective optimization problem in the present invention; the PSO algorithm has the advantages of fast convergence speed and strong global search ability, and is suitable for optimizing the performance weight factor in the present invention.

Claims

1. A synchronizer parameter multi-objective optimization method based on NSGA(Ⅱ)-PSO, characterized by: The following steps are involved: S1: Based on the shifting system analysis, a dynamic model of the shifting process is established; S2: Select shifting time, maximum impact between teeth, and sliding friction work as shifting performance evaluation indicators, and rated power of the shifting motor as the economic performance evaluation indicator; S3: Analyze the influence of different structural parameters and control parameters on shifting performance and economic performance, use importance analysis to explore the influence of parameters on evaluation indicators, and determine the optimization variables; S4: Taking shifting performance and economic performance as optimization objectives, the optimization objectives are normalized, the constraints of the objective function and optimization variables are determined, and the NSGA(II)-PSO optimization algorithm is used to perform multi-objective optimization of the structural parameters and control parameters.

2. The synchronizer parameter multi-objective optimization method based on NSGA(II)-PSO according to claim 1, characterized in that: In the step S1, the gear shifting process dynamics model includes a power source model and a gear shifting process model.

3. The synchronizer parameter multi-objective optimization method based on NSGA(II)-PSO according to claim 1, characterized in that: In step S2, the shift time calculation equation is: shift =∑t i ; In the formula, t shift is the shift time, t i The time used for each stage of gear shifting; The impact degree calculation equation is: max =max(m slv )|v slv (t i+1 )-v slv (t i )|; In the formula, I max is the maximum impact between teeth, m slv is the mass of the joint sleeve, v slv is the axial moving speed of the coupling sleeve; The sliding friction work calculation equation is: Where W s is the friction work, T syn is the synchronous friction torque, Δω is the speed difference; The rated power equation of the shift motor is: Where P r F is the rated power of the shift motor; shift is the shifting force; R cam is the camshaft rotation radius; a cam is the camshaft rotation angle; μ1 and μ2 are the friction coefficients; x slv is the displacement of the coupling sleeve; η is the transmission efficiency of the reduction mechanism; t is the gear shifting time.

4. The synchronizer parameter multi-objective optimization method based on NSGA(II)-PSO according to claim 1, characterized in that: In step S3, the structural parameters analyzed include the chamfer angle a between the tooth end of the coupling sleeve and the coupling ring gear. gear , Synchronous ring friction cone angle a cone , equivalent input moment of inertia J in , Synchronous ring moment of inertia J syn , the mass of the joint sleeve m slv , Average radius of friction cone surface of synchronizer ring r cone , friction coefficient between the teeth of the coupling sleeve and the coupling ring gear μ slvgr And the friction coefficient μ of the synchronizer ring cone cone ; Through importance analysis, the friction coefficient μ of the synchronizer ring cone is selected. cone , Average radius of friction cone surface of synchronizer ring r cone , Synchronous ring friction cone angle a cone , chamfer angle a of the tooth end of the coupling sleeve and the coupling ring gear gear , the mass of the joint sleeve m slv and equivalent input moment of inertia J in Optimize; the selected control parameters include shift force F shift and the speed difference Δω.

5. The synchronizer parameter multi-objective optimization method based on NSGA(II)-PSO according to claim 1, characterized in that: In step S4, the selected optimization target is normalized, and the formula is as follows: In the formula, t shift is the shift time; Q1(t shift ) is the normalized value of the shift time; I max is the maximum impact between teeth; Q2(I max ) is the normalized value of the maximum impact between teeth; W s is the sliding friction work; Q3(W s ) is the normalized value of sliding friction work; P r is the rated power of the shift motor; Q4(P r ) is the normalized value of the rated power of the shift motor; The optimization objective function is: Q=λ1f(Q1(t shift ),Q2(I max ),Q3(W s ))+λ2Q4(P r ); In the formula, λ1 is the weight factor of shifting performance; λ2 is the weight factor of economic performance; The constraints are: In the formula, a cone is the friction cone angle of the synchronizer ring, T b is the tooth end locking torque, T syn is the synchronous friction torque, X min is the minimum value of the structural parameter, X is the structural parameter, X max is the maximum value of the structural parameter, Y min is the minimum value of the control parameter, Y is the control parameter, Y max is the maximum value of the control parameter.

6. The synchronizer parameter multi-objective optimization method based on NSGA(II)-PSO according to claim 5, characterized in that: In the optimization stage, the inner layer uses the non-dominated sorting genetic algorithm II with elite strategy to balance the contradictions among shifting time, maximum impact degree between teeth, and sliding friction work. The outer layer uses the particle swarm optimization algorithm to optimize the shifting performance weight factor and economic performance weight factor.

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