Method for optimizing torsional vibration characteristic simulation data of vehicle transmission system based on PSO (Particle Swarm Optimization)

Abstract

The invention provides a vehicle transmission system torsional vibration characteristic simulation data optimization method based on PSO. The method comprises the steps that S1, a transmission system torsional vibration characteristic simulation model is built in torsional vibration characteristic simulation software according to simulation information of a whole vehicle; s2, simulation analysis of a vehicle transmission system is conducted through simulation software, and second-order angular acceleration data of a transmission input shaft after vibration of a power source is damped through a damper are extracted; s3, optimizing parameters in the process of calculating the RMS value of the second-order angular acceleration of the input shaft of the transmission by using a particle swarm optimization method; and S4, calculating a second-order angular acceleration RMS value of the input shaft of the transmission according to parameters obtained by particle swarm optimization. According to the method, the points are selected from the RMS, optimization of the points is calculated repeatedly, and the obtained RMS value can reflect trend change of original data to the maximum extent.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle transmission simulation, and in particular relates to a method for optimizing simulation data of torsional vibration characteristics of a vehicle transmission system based on PSO. Background Art

[0002] In view of the continuous expansion and widening of the scale of the domestic and foreign automobile markets at this stage, more and more cars are pouring into the trading market. Before delivering the car to the user, its riding comfort must be fully considered, which is directly related to the vibration suppression performance of the vehicle. Generally speaking, the main vibration of the vehicle comes from the irregular excitation of the engine or other power sources, which then spreads throughout the transmission system to the body, seats and other positions. The original component that plays a key role in reducing torsional vibration in the transmission system is the torsional vibration damper (or dual mass flywheel, etc.).

[0003] In view of the high cost, complex construction process and long development cycle of traditional vehicle transmission test benches, spare parts companies can verify the adaptability of the developed vibration reduction products and vehicle models based on the simulation software related to the torsional vibration characteristics of the vehicle transmission system, and provide solutions for the parts required by the vehicle manufacturers to improve the product adaptation effect and shorten the development cycle of new models. Vehicle manufacturers and spare parts manufacturers are particularly concerned about the RMS value of the second-order angular acceleration of the transmission input shaft after the irregular vibration of the source engine is damped by the shock absorber. Therefore, in order to make the RMS value better reflect the size and trend of the original data, it is particularly important to optimize the relevant parameters in the RMS calculation process. Summary of the invention

[0004] The purpose of the present invention is to provide a method for optimizing simulation data of torsional vibration characteristics of a vehicle transmission system based on PSO, and to solve the RMS value of the simulation data obtained by the vehicle torsional vibration characteristics simulation software. The RMS is calculated by calculating one RMS for every few data points, rather than a parameter optimization method for all data points.

[0005] Vehicle manufacturers and parts manufacturers are particularly concerned about the second-order angular acceleration RMS value of the transmission input shaft in the vehicle transmission system, which is used to characterize the vibration reduction effect of the source engine vibration through the torsional vibration damper. Therefore, it is necessary to export the numerical value obtained by the simulation software and then post-process it through matlab to calculate the RMS value. The present invention uses a particle swarm optimization algorithm to optimize the number of selected points and repeated calculation points for RMS value calculation. The RMS calculated by optimizing the parameters can reflect the main characteristics of the original data to a greater extent. The technical scheme adopted is as follows:

[0006] A method for optimizing simulation data of torsional vibration characteristics of a vehicle transmission system based on PSO comprises the following steps:

[0007] Step S1: construct a simulation model of the torsional vibration characteristics of the transmission system in the torsional vibration characteristics simulation software according to the simulation information of the whole vehicle, specifically:

[0008] Step S1.1: Based on the transmission system topology diagram of the vehicle, the whole framework of the torsional vibration characteristics of the vehicle transmission system is modeled by the concentrated mass method in the simulation software.

[0009] Step S1.2: Set the corresponding parameters in the model according to the geometric shape, torsional stiffness, rotational inertia, torsional damping and gear ratio of each component of the vehicle transmission system.

[0010] Step S1.3: Build a steady-state torque output module at each speed according to the external characteristic curve of the vehicle power source.

[0011] Step S2: Use simulation software to perform simulation analysis on the vehicle transmission system, and extract the second-order angular acceleration data of the transmission input shaft after the power source vibration is damped by the shock absorber, specifically:

[0012] Step S2.1: Perform simulation using the vehicle transmission system torsional vibration simulation model built based on the simulation software in step S1.

[0013] Step S2.2: After that, an order analysis is performed, and the second-order angular acceleration of the gearbox input shaft, which is of most concern to the manufacturer, is extracted using a fast Fourier transform (FFT).

[0014] Step S3: Optimizing the parameters in the process of calculating the RMS value of the second-order angular acceleration of the transmission input shaft by using the particle swarm optimization method, specifically:

[0015] Step S3.1: Preprocess the original data and group the original data according to the number of groups calculated by the RMS value.

[0016] Step S3.2: The original value, i.e., the second-order angular acceleration of the transmission input shaft, is used as the comparison value after preprocessing, and the square algebraic sum of the difference between the RMS calculation value and the comparison value is used as the particle fitness. The particle swarm optimization algorithm is used to optimize the two parameters of the number of selected points and the number of repeated calculation points for RMS value calculation, in order to minimize the cost of penalizing the particle fitness.

[0017] Step S4: Calculate the RMS value of the second-order angular acceleration of the transmission input shaft using the parameters obtained by particle swarm optimization: the number of selected points for RMS value calculation and the number of repeated calculation points.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] The optimization of the parameters in the RMS calculation of the torsional vibration simulation of the vehicle transmission system based on the simulation software, the optimization of the number of points selected in the calculation of RMS, and the optimization of the number of points repeatedly calculated, so that the RMS value can reflect the trend changes of the original data to the greatest extent. At the same time, the parameter optimization idea of ​​particle swarm optimization can save time, avoid manual parameter setting, waste time and the data characteristics are too far from the original data. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 for Figure 1 It is the flow chart of the parameter optimization technology based on PSO;

[0021] Figure 2 It is the structural topology diagram of the vehicle transmission system;

[0022] Figure 3 The concentrated mass method model for torsional vibration simulation of a vehicle transmission system built based on the transmission system torsional vibration characteristic simulation software in the present invention;

[0023] Figure 4 It is the amplitude-frequency diagram of the second-order angular acceleration order analysis in the angular acceleration order analysis of the transmission input shaft;

[0024] Figure 5 is the original data diagram of the angular acceleration of the transmission input shaft;

[0025] Figure 6 This is a diagram of the RMS solution results of simulation parameters using PSO tuning parameters. DETAILED DESCRIPTION

[0026] The following will be described in more detail with reference to the schematic diagram of the vehicle transmission system torsional vibration characteristics simulation data optimization method based on PSO of the present invention, wherein the preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein, while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation of the present invention.

[0027] A PSO-based method for optimizing simulation data of torsional vibration characteristics of vehicle transmission system, such as Figure 1 As shown, specifically including:

[0028] Step S1: Building a simulation model of the torsional vibration characteristics of the transmission system in the simulation software according to the simulation information of the whole vehicle. Specifically:

[0029] Step S1.1: The transmission system topology diagram of the vehicle is simulated in the simulation software using the concentrated mass method. Figure 2 The vehicle transmission system structural topology diagram shown is used to model the torsional vibration characteristics of the entire vehicle transmission system.

[0030] Design a transmission system model that includes mass points and connection elements, clarify the types of connection elements, and their associated physical quantities, such as stiffness, damping, transmission ratio and other parameters that may be involved.

[0031] Step S1.2: Set corresponding parameters in the model according to the torsional stiffness, rotational inertia, torsional damping and gear ratio of each transmission component designed for the vehicle transmission system.

[0032] Among them, the concentrated mass method should be used to convert the translational inertia of the vehicle body into rotational inertia. According to the law of conservation of energy, its movement is converted into a rotation with the wheel radius as the radius, and the inertia force of the vehicle body is converted into an inertia moment with a lever arm as the wheel radius.

[0033] Step S1.3: Build a steady-state torque output module at each speed according to the external characteristic curve of the vehicle power source.

[0034] Power modules can be flexibly added or removed for single or multiple power sources of gasoline and diesel engine vehicles, pure electric vehicles, and hybrid vehicles.

[0035] Step S2: Use simulation software to perform simulation analysis on the automobile transmission system, and extract the second-order angular acceleration data of the transmission input shaft after the vibration reduction treatment by the torsional vibration damper (or dual-mass flywheel, etc.).

[0036] Step S2.1: Using the Figure 3 , simulation is carried out based on the vehicle transmission system torsional vibration simulation model built by simulation software.

[0037] If it is a pure electric vehicle, set the opening to 1; if it is a fuel vehicle, set the opening to 1; if it is a hybrid electric vehicle, consider the special working condition that when the throttle opening is 1, set the opening according to the external characteristics of the drive motor so that the torque output to the transmission system by the fuel engine and the drive motor is equal.

[0038] In addition to the three commonly used typical types of vehicles mentioned above, the settings of other types of vehicles are also considered in the above method. The setting of the load can be added after the body module.

[0039] Step S2.2: Use the fast Fourier transform method to process the vibration angular acceleration data, calculate the vibration order amplitude-frequency characteristics, and then obtain the RMS value for evaluating the vibration characteristics. The present invention only cares about the second-order angular acceleration of the transmission input shaft, see Figures 4-5 .

[0040] Figure 4 In , the horizontal axis is the frequency, and the vertical axis is the speed of the transmission input shaft;

[0041] Figure 5 In , the horizontal axis is the transmission input shaft speed, and the vertical axis is the transmission input shaft angular acceleration;

[0042] "2" means the second-order angular acceleration of the transmission input shaft.

[0043] Step S3: Optimizing the parameters for calculating the RMS value of the second-order angular acceleration of the transmission input shaft by using a particle swarm optimization method.

[0044] Step S3.1: Preprocessing the original data, ie, the value of the second-order angular acceleration of the transmission input shaft (data of the second-order angular acceleration in the speed domain).

[0045] The original data is approximately considered to obey the normal distribution, so the outliers are eliminated based on the 3σ principle. 99.73% of the data will fall within u±3σ, that is, the probability that the data is distributed in (u-3σ,u+3σ) is 0.9973.

[0046] The removed abnormal points are replaced by the corresponding values ​​of the previous speed value calculated by the simulation software, see Figure 5 .

[0047]

[0048] - Second order angular acceleration of the transmission input shaft.

[0049] The original data is grouped, and the number of groups is the same as the number of groups for calculating the RMS value.

[0050] If there are any remaining numerical points after grouping, they should be the second-order angular acceleration corresponding to the highest speed, which is not very important for evaluating the vibration reduction effect of the shock absorber. Therefore, they are not considered.

[0051]

[0052] x represents the number of groups for calculating the RMS value, m represents the number of original data points obtained by the simulation software, k represents the number of repeated calculation points for calculating the RMS value (referring to the number of repeated calculation points between two adjacent groups), and n represents the number of values ​​in each group.

[0053] Step S3.2: The original value, i.e., the second-order angular acceleration value of the transmission input shaft, is used as the comparison value after preprocessing. Since the original data is divided into multiple groups for RMS value calculation, the RMS value of each group of data is calculated.

[0054]

[0055] In formula (3), i is each group, RMS i The RMS value calculated for each data group, n i The number of data in each data group, d ij is the value of the jth data point in the i-th data group.

[0056] The average for each group is calculated as follows:

[0057]

[0058] The particle fitness is penalized at the cost of the square algebraic sum of the difference between each group of RMS calculation values ​​and the average of each group of corresponding comparison values. As shown in formula (5):

[0059]

[0060] In formula (5), J is the fitness of the particle, d i The mean value for each data group, from 1 to x.

[0061] Using the particle swarm optimization algorithm, the initial value of the particle is given artificially, the initial position of the particle is [n, k], the initial velocity direction of the particle is [v n ,v k ], that is, each particle contains two-dimensional information.

[0062] The two parameters of the number of selected points and the number of repeated calculation points for RMS value calculation are optimized in order to minimize the cost penalty.

[0063] The particle's position and velocity are updated at each iteration as follows:

[0064]

[0065] In formula (6):

[0066] is the velocity of particle i at time t, is the velocity of particle i at time t+1, is the position of particle i at time t, is the position of particle i at time t+1;

[0067] p i is the historical optimal position of particle i, g is the global optimal position, w is the inertia weight, c1, c2 are learning factors, and r1, r2 are random numbers.

[0068] When the set iteration error condition is met or the maximum number of iterations is reached, the optimal parameter combination [n opt ,k opt ].

[0069] Step S4: Optimize the parameters obtained by particle swarm optimization [n opt ,k opt ], using matlab to calculate the second-order angular acceleration RMS value of the transmission input shaft. Finally, the fitting curve is obtained through cubic spline curve fitting.

[0070] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A method for optimizing simulation data of torsional vibration characteristics of vehicle transmission system based on PSO, characterized in that: The following steps are involved: Step S1: constructing a simulation model of the torsional vibration characteristics of the transmission system in the torsional vibration characteristics simulation software according to the simulation information of the whole vehicle; Step S2: using simulation software to perform simulation analysis on the vehicle transmission system, and extracting the second-order angular acceleration data of the transmission input shaft after the vibration of the power source is damped by the shock absorber; Step S3: Optimizing parameters in the process of calculating the RMS value of the second-order angular acceleration of the transmission input shaft by using a particle swarm optimization method; Step S4: Calculate the second-order angular acceleration RMS value of the transmission input shaft using the parameters obtained by particle swarm optimization.

2. The method for optimizing simulation data of torsional vibration characteristics of vehicle transmission system based on PSO according to claim 1, characterized in that: Step S1 specifically includes the following steps: Step S1.1, for the transmission system topology diagram of the vehicle, the whole framework modeling of the torsional vibration characteristics of the transmission system of the vehicle is performed by using the concentrated mass method in the simulation software; Step S1.2, setting corresponding parameters in the model; Step S1.3: construct a steady-state torque output module at each speed according to the external characteristic curve of the vehicle power source.

3. The method for optimizing simulation data of torsional vibration characteristics of vehicle transmission system based on PSO according to claim 1, characterized in that: Step S2 specifically includes the following steps: Step S2.1: Simulate the vehicle transmission system torsional vibration simulation model built based on the simulation software; Step S2.2: Perform order analysis to extract the second-order angular acceleration of the gearbox input shaft.

4. The method for optimizing simulation data of torsional vibration characteristics of vehicle transmission system based on PSO according to claim 1, characterized in that: Step S3 specifically includes the following steps: Step S3.1, pre-processing the original data, and grouping the original data according to the number of groups calculated by the RMS value; Step S3.2, using the original value, i.e., the second-order angular acceleration of the transmission input shaft, after numerical preprocessing as the comparison value, and using the square algebraic sum of the difference between the RMS calculated value and the comparison value as the particle fitness; The particle swarm optimization algorithm is used to optimize the two parameters of the number of selected points and the number of repeated calculation points for RMS value calculation, in order to minimize the cost of penalizing particle fitness.

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