A method and system for optimizing braking noise

Abstract

This invention discloses a method and system for optimizing braking noise, belonging to the field of vehicle technology. The method includes: determining the energy contribution of each component through simulation calculation when braking noise is detected during road and bench tests; identifying the key components inducing braking noise based on the energy contribution of each component; determining the key free modes of the key components inducing braking noise; and adjusting the structure of the key components based on the key free modes to eliminate braking noise. This invention not only identifies which component is the key component but also determines the key free modes inducing braking noise, allowing engineers to modify designs specifically to optimize for the key free modes, thus improving development efficiency and success rate.

Description

Technical Field

[0001] This invention belongs to the field of vehicle technology, specifically relating to a method and system for optimizing braking noise. Background Technology

[0002] Braking noise is high-frequency noise generated by vibration during braking system operation, which can seriously affect the user's driving experience. Current technologies typically address this by altering the material properties of brake pads or adding components such as sound-absorbing pads to absorb sound and vibration. However, the causes of braking noise are complex; braking noise under different operating conditions may be generated by different components of the braking system. Current technologies cannot accurately pinpoint the specific component generating the braking noise, resulting in low accuracy. Furthermore, regarding low-frequency noise, due to the large energy of structural vibrations and the limited vibration absorption capacity of sound-absorbing pads, the problem cannot be effectively solved. Summary of the Invention

[0003] One objective of this invention is to provide a braking noise optimization method and system that can solve the technical problem in the prior art of not being able to accurately locate the specific component that generates braking noise.

[0004] According to a first aspect of the present invention, a method for optimizing braking noise is provided, comprising:

[0005] When braking noise is detected during brake road tests and bench tests, the energy contribution of each component is determined through simulation calculations.

[0006] The key components that induce braking noise are determined based on the energy contribution of each component.

[0007] Identify the key free modes of the critical components that induce braking noise;

[0008] The key components are structurally adjusted based on the key free modes to eliminate braking noise.

[0009] Optionally, determining the energy contribution of each component through simulation calculation includes:

[0010] The unstable modes of the braking angle assembly were determined based on finite element complex modal analysis;

[0011] Modal strain energy of each component is calculated for the unstable mode in which noise occurs, and the energy contribution of each component is calculated.

[0012] Optionally, the determination of the unstable modes of the braking angle assembly based on finite element complex modal analysis includes:

[0013] A modal finite element analysis model of the braking angle assembly under braking conditions was constructed.

[0014] Calculate the mass matrix and stiffness matrix of the braking angle assembly under braking force to form the differential equation of structural vibration motion;

[0015] Solve for the system's eigenvalues ​​using the frequency calculation formula;

[0016] The damping ratio is calculated based on the eigenvalues, and the damping ratio represents the stability of the corresponding mode.

[0017] Optionally, after determining the unstable modes of the braking angle assembly based on finite element complex modal analysis, the method further includes:

[0018] Compare the unstable modal frequencies calculated by benchmark simulation with the actual noise occurrence frequencies;

[0019] Compare the unstable mode shapes with the measured ODS mode shapes;

[0020] The accuracy of the system simulation model is determined by two dimensions: the noise occurrence frequency and the mode shape.

[0021] Optionally, determining the key free modes of the critical component that induces braking noise includes:

[0022] Perform free modal calculations on key components;

[0023] The unstable and free modes of the key components are convolved for computation.

[0024] The key free modes that induce braking noise were determined based on the calculation results.

[0025] Optionally, the method further includes:

[0026] When braking noise is detected during brake road tests and bench tests, noise signals are collected.

[0027] Perform Fast Fourier Analysis on the noise signal to confirm the frequency range and peak frequency of the noise;

[0028] Determine whether the noise belongs to low-frequency structural noise based on the frequency range of the noise;

[0029] If the noise is low-frequency structural noise, use a vibration meter to conduct an ODS deformation test, and expand the ODS data in the frequency domain to obtain the mode shape of the braking system at the noise frequency.

[0030] According to a second aspect of the present invention, a system for applying a braking noise optimization method according to a first aspect of the present invention is provided, comprising:

[0031] The calculation module is used to determine the energy contribution of each component through simulation calculation when braking noise is detected during brake road tests and bench tests.

[0032] The first determining module is used to determine the key components that induce braking noise based on the energy contribution of each component.

[0033] The second determining module is used to determine the key free modes of the key components that induce braking noise;

[0034] An adjustment module is used to perform structural adjustments on the key components based on the key free modes in order to eliminate braking noise.

[0035] Optionally, the computing module is further configured to:

[0036] The unstable modes of the braking angle assembly were determined based on finite element complex modal analysis;

[0037] Modal strain energy of each component is calculated for the unstable mode in which noise occurs, and the energy contribution of each component is calculated.

[0038] Optionally, the computing module is further configured to:

[0039] A modal finite element analysis model of the braking angle assembly under braking conditions was constructed.

[0040] Calculate the mass matrix and stiffness matrix of the braking angle assembly under braking force to form the differential equation of structural vibration motion;

[0041] Solve for the system's eigenvalues ​​using the frequency calculation formula;

[0042] The damping ratio is calculated based on the eigenvalues, and the damping ratio represents the stability of the corresponding mode.

[0043] Optionally, the computing module is further configured to:

[0044] Compare the unstable modal frequencies calculated by benchmark simulation with the actual noise occurrence frequencies;

[0045] Compare the unstable mode shapes with the measured ODS mode shapes;

[0046] The accuracy of the system simulation model is determined by two dimensions: the noise occurrence frequency and the mode shape.

[0047] The beneficial effects of this invention are as follows: This invention can not only identify which component is the key component, but also identify the key free modes that induce braking noise, allowing engineers to modify the design in a targeted manner and optimize specifically for the key free modes, thereby improving development efficiency and the success rate of solving noise problems. Attached Figure Description

[0048] Figure 1 This is a flowchart of a braking noise optimization method according to an embodiment of the present invention. Detailed Implementation

[0049] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0050] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0051] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0053] In the specification of this invention, the terms "first" and "second" may explicitly or implicitly include one or more of the same feature. In the description of this invention, unless otherwise stated, "multiple" means two or more. Furthermore, in the specification, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0054] like Figure 1 As shown in the figure, this embodiment introduces a braking noise optimization method, including steps 1100-1400.

[0055] Step 1100: If braking noise is detected during brake road tests and bench tests, determine the energy contribution of each component through simulation calculations.

[0056] A braking system comprises multiple components, such as brake pads, brake discs, brake calipers, pistons, and steering knuckles. When braking noise occurs, its energy originates from friction. Although all components vibrate, the contribution of different components to braking noise varies. Some components absorb energy, while others release it. The energy contribution of each component represents the modal strain energy of the vibrations of each component in the system excited by friction.

[0057] Step 1200: Determine the key components that induce braking noise based on the energy contribution of each component.

[0058] After calculating the energy contribution of each component, the key components that induce braking noise can be identified based on the magnitude of their energy contributions. For example, by ranking the components according to their energy contributions, the component with the largest energy contribution is identified as the key component that induces braking noise.

[0059] Step 1300: Determine the key free modes of the critical components that induce braking noise.

[0060] Free modes represent the inherent vibration characteristics of a component in a free state. Critical free modes correspond to the occurrence of braking noise, and their frequencies are close to the frequencies at which the critical component generates noise in the braking system. Modal decomposition of the previously obtained unstable modes (operating modes) of the critical component in its free mode space yields the critical free modes that induce braking noise.

[0061] Step 1400: Based on the key free mode, perform structural adjustments on the key components to eliminate braking noise.

[0062] Based on the mode shapes of key free modes, the design of key components is modified to change their natural frequencies, thus avoiding the frequency range that easily induces noise. Frequency shifting moves the key components away from the main excitation frequency region during braking, thereby preventing resonance. For example, stiffness can be increased by adding reinforcing ribs or changing thickness, thereby raising the natural frequency; torsional stiffness can be increased by changing the structural shape or adding connection points, thus raising the frequency; or mass blocks can be designed to lower the frequency.

[0063] In this embodiment, determining the energy contribution of each component through simulation calculation includes: determining the unstable modes of the braking angle assembly based on finite element complex modal analysis; calculating the modal strain energy of each component corresponding to the unstable modes in which noise occurs, and calculating the energy contribution of each component.

[0064] Complex modal analysis (CMA) is a dynamic method used to analyze non-conservative systems. In braking systems, friction is a source of noise energy. CMA can solve for the eigenvalues ​​of the system; the real part represents the mode stability, and the imaginary part represents the mode frequency. CMA can identify which modes become unstable under braking conditions; these unstable modes are potential sources of noise.

[0065] Modal strain energy is the energy stored internally by a structure due to its deformation when it vibrates in a specific mode. In unstable modes, this study analyzes whether each component contributes positively or negatively to noise energy during frictional contact.

[0066] Specifically, the determination of the unstable modes of the braking angle assembly based on finite element complex modal analysis includes: building a finite element analysis model of the braking angle assembly under braking conditions; calculating the mass matrix and stiffness matrix of the braking angle assembly under braking force to form the structural vibration motion differential equation; solving the eigenvalues ​​of the system according to the frequency calculation formula; and calculating the damping ratio according to the eigenvalues, wherein the damping ratio represents the stability of the corresponding mode.

[0067] First, a 3D digital model of the braking angle assembly is required, including all components within the assembly. Then, the complex 3D geometry is discretized into numerous simple, small elements (such as tetrahedrons and hexahedrons), connected by nodes. Material properties are defined for each component, including parameters such as density, Young's modulus, and Poisson's ratio. A simulation model is then constructed based on braking conditions. During manufacturing and machining, tolerance factors can lead to discrepancies between the actual product and the design; therefore, parameter calibration is necessary to ensure consistency between the simulation results and the actual structural data.

[0068] The differential equations of motion for structural vibration are as follows:

[0069] ;

[0070] in, For the quality matrix, Here is the stiffness matrix.

[0071] The formula for calculating frequency is:

[0072] ;

[0073] The system eigenvalues ​​represent the system's natural frequencies. Due to the friction between the brake disc and the friction pads, the system stiffness matrix... Non-positive definite system eigenvalues The solution is:

[0074] ;

[0075] in The real part of the eigenvalue represents the damping coefficient; The imaginary part of the eigenvalues ​​represents the natural frequency of the system.

[0076] The damping ratio formula is:

[0077] ;

[0078] Damping ratio Indicates the modal stability of the system, when This indicates that the corresponding mode is unstable, and the vibration amplitude diverges over time, inducing braking noise.

[0079] In this embodiment, after determining the unstable modes of the braking angle assembly based on finite element complex modal analysis, the method further includes: benchmarking the unstable mode frequencies calculated by simulation with the actual noise occurrence frequencies; benchmarking the unstable mode shapes with the measured ODS (Operating Deflection Shape) shapes; and determining the accuracy of the system simulation model from the two dimensions of noise occurrence frequency and mode shape.

[0080] The results of the complex modal analysis also need to be verified to prove that the simulation model is reliable. Only after the simulation model is verified to be accurate can the subsequent optimization process proceed. The accuracy of the simulation model is verified using both frequency and mode shape dimensions.

[0081] Complex modal analysis yields unstable modes and their frequency values, which are the simulated values. In the experiment, braking noise signals are detected by sensors, and the noise spectrum is obtained through Fast Fourier Transform (FFT), thus providing the actual noise frequency, which is the experimental value. The relative error between the simulated and experimental values ​​is then calculated. If the relative error is within a specified range, the frequency calibration result is considered accurate.

[0082] Unstable mode shapes are obtained through complex modal analysis. ODS mode shapes are obtained through ODS deformation testing. The unstable mode shapes are compared with the ODS mode shapes; if the agreement is high, the comparison results are considered accurate.

[0083] In this embodiment, determining the key free modes of the key components that induce braking noise includes: performing free mode calculation on the key components; performing convolution calculation on the unstable modes and free modes of the key components; and determining the key free modes that induce braking noise based on the calculation results.

[0084] By performing free modal calculations on key components, the inherent vibration characteristics of those components can be obtained. Specifically, the key component is separated from the assembly model, and its free modes are calculated in finite element software without any constraints. The free modal calculations yield the free modal frequencies and corresponding mode shapes. These properties are determined by the component's material and geometry.

[0085] The purpose of convolution computation is to decouple the working mode, calculate the contribution of each free mode, comprehensively score each free mode, and identify the free mode most relevant to the unstable mode of the system, which is the critical free mode. Usually, the free mode with the highest score is the critical free mode.

[0086] This embodiment achieves precise penetration from identifying which component is faulty to pinpointing the specific areas of the problem within that component. Traditional methods only identify the critical component, leading to blind modifications such as simple thickening. This method, however, not only determines the critical component but also identifies the key free modes that induce braking noise. This allows engineers to make targeted design modifications, specifically optimizing for the key free modes, thus improving development efficiency and success rate.

[0087] After making structural adjustments to the key components, it is also necessary to recalculate the new structure, solve for the damping ratio of the new structure, and verify whether the new structure is effective.

[0088] In this embodiment, the method further includes: when braking noise is detected during brake road tests and bench tests, collecting noise signals; performing fast Fourier analysis on the noise signals to confirm the frequency range and peak frequency of the noise; determining whether the noise belongs to low-frequency structural noise based on the frequency range of the noise; if it belongs to low-frequency structural noise, using a vibration meter to conduct ODS deformation tests, and expanding the ODS data in the frequency domain to obtain the mode shape of the braking system at the noise frequency.

[0089] Noise signals are collected by sensors, and sound signals during the braking noise process are recorded. The sound pressure wave is converted into an electrical signal whose voltage changes over time.

[0090] The time-domain signal is then converted into a frequency-domain signal using Fast Fourier Analysis to obtain the spectrum of the noise signal, and thus the frequency range of the noise.

[0091] Structural noise is typically related to the natural vibrations of a structure and occurs at higher frequencies. It usually manifests as one or more sharp, high-amplitude single peaks. In contrast, other noises, such as aerodynamic noise, typically have lower frequencies and exhibit a continuous, wide-band spectrum. If the spectrum shows clear high-frequency spikes, it can be determined that the noise is braking noise caused by structural vibration and is therefore structural noise.

[0092] Low-frequency structural noise typically ranges from 1kHz to 3kHz. After identifying it as low-frequency structural noise, it is necessary to further determine how the entire braking system vibrates at a specific noise frequency. During ODS testing, numerous sensors are placed on all potentially vibrating components to simultaneously collect vibration data from all sensor channels while reproducing the braking noise. One sensor is used as a reference point to determine the relative phase of the vibration at all other measuring points.

[0093] Fast Fourier analysis was performed on all vibration data to obtain the spectrum of each measuring point. The peak noise frequency was then identified within the spectrum of all measuring points. The vibration amplitude and phase difference relative to a reference point at this frequency were extracted for each measuring point. Finally, the amplitude and phase information of each measuring point at the peak noise frequency were mapped onto the geometric model of the braking system to obtain the deformation process.

[0094] This embodiment describes a system applied to a braking noise optimization method described in any embodiment of the present invention, comprising:

[0095] The calculation module is used to determine the energy contribution of each component through simulation calculation when braking noise is detected during brake road tests and bench tests.

[0096] The first determining module is used to determine the key components that induce braking noise based on the energy contribution of each component.

[0097] The second determining module is used to determine the key free modes of the key components that induce braking noise;

[0098] An adjustment module is used to perform structural adjustments on the key components based on the key free modes in order to eliminate braking noise.

[0099] In this embodiment, the calculation module is further used for:

[0100] The unstable modes of the braking angle assembly were determined based on finite element complex modal analysis;

[0101] Modal strain energy of each component is calculated for the unstable mode in which noise occurs, and the energy contribution of each component is calculated.

[0102] In this embodiment, the calculation module is further used for:

[0103] A modal finite element analysis model of the braking angle assembly under braking conditions was constructed.

[0104] Calculate the mass matrix and stiffness matrix of the braking angle assembly under braking force to form the differential equation of structural vibration motion;

[0105] Solve for the system's eigenvalues ​​using the frequency calculation formula;

[0106] The damping ratio is calculated based on the eigenvalues, and the damping ratio represents the stability of the corresponding mode.

[0107] In this embodiment, the calculation module is further used for:

[0108] Compare the unstable modal frequencies calculated by benchmark simulation with the actual noise occurrence frequencies;

[0109] Compare the unstable mode shapes with the measured ODS mode shapes;

[0110] The accuracy of the system simulation model is determined by two dimensions: the noise occurrence frequency and the mode shape.

[0111] While specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention.

[0112] Those skilled in the art will recognize that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0113] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and equipment can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0114] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0115] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0116] In addition, the functional modules in the embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0117] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0118] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0119] It should be understood that the sequence numbers of the steps in the invention's content and embodiments do not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention. The foregoing description of embodiments of this disclosure has been provided for illustrative and descriptive purposes. The foregoing description is not exhaustive and is not intended to limit this disclosure to the exact form disclosed. Various modifications and variations may exist based on the foregoing teachings, or various modifications and variations may be derived from the practice of this disclosure. These embodiments were chosen and described to illustrate the principles of this disclosure and its practical application, so that those skilled in the art can utilize this disclosure in various implementations and modifications suitable for the specific purpose of the concept.

Claims

1. A method of brake noise optimization, characterized by, The method comprises the following steps: In the case of detecting brake road test and brake noise in the bench test, the energy contribution of each component is determined by simulation calculation; According to the energy contribution of each component, the key component inducing brake noise is determined; according to the size of the energy contribution of each component, the components are sorted, and the component with the largest energy contribution is the key component inducing brake noise; Determine the key free modal of the key component inducing brake noise; Based on the key free modal, the structure of the key component is adjusted to eliminate brake noise; The energy contribution of each component is determined by simulation calculation, which comprises the following steps: Determine the unstable modal of the brake angle assembly based on finite element complex modal analysis; According to the unstable modal corresponding to the noise, the modal strain energy of each component is calculated, and the energy contribution of each component is calculated.

2. The method of claim 1, wherein, The method comprises the following steps: Build a modal finite element analysis model of the brake angle assembly under braking condition; Calculate the mass matrix and stiffness matrix of the brake angle assembly under braking force, and form the structure vibration motion differential equation; Solve the characteristic value of the system according to the frequency calculation formula; Calculate the damping ratio according to the characteristic value, which represents the stability of the corresponding modal.

3. The method of claim 1, wherein, After determining the unstable modal of the brake angle assembly based on finite element complex modal analysis, the method further comprises the following steps: Compare the unstable modal frequency of simulation calculation with the actual noise frequency; Compare the unstable modal shape with the measured ODS modal shape; Determine the accuracy of the system simulation model from the two dimensions of noise frequency and modal shape.

4. The method of claim 1, wherein, The method further comprises the following steps: In the case of detecting brake road test and brake noise in the bench test, collect noise signal; Perform fast Fourier analysis on the noise signal to confirm the frequency range and peak frequency of the noise; Determine whether it belongs to low-frequency structural noise according to the frequency range of the noise; 5. The method of claim 1, wherein, If it belongs to low-frequency structural noise, use the vibration measuring instrument to carry out ODS deformation test, and spread the ODS data in frequency domain to obtain the modal shape of the brake system under the noise frequency. The method comprises the following steps: A calculation module is configured to determine the energy contribution of each component by simulation calculation in the case of detecting brake road test and brake noise in the bench test; A first determination module is configured to determine the key component inducing brake noise according to the energy contribution of each component; A second determination module is configured to determine the key free modal of the key component inducing brake noise; 6. A system for use in a brake noise optimisation method according to any one of claims 1 to 5, characterised in that, An adjustment module is configured to adjust the structure of the key component based on the key free modal to eliminate brake noise. The calculation module is further configured to: Determine the unstable modal of the brake angle assembly based on finite element complex modal analysis; According to the unstable modal corresponding to the noise, the modal strain energy of each component is calculated, and the energy contribution of each component is calculated. The calculation module is further configured to:

7. The system of claim 6, wherein, ​ ​ ​ 8. The system of claim 7, wherein, ​ Build a modal finite element analysis model of the brake corner assembly under the braking condition; Calculate the mass matrix and the stiffness matrix of the brake corner assembly under the braking force, and form a structure vibration motion differential equation; Solve the characteristic value of the system according to a frequency calculation formula; Calculate a damping ratio according to the characteristic value, the damping ratio representing the stability of the corresponding mode.

9. The system of claim 7, wherein, The computing module is further configured to: Compare the unstable mode frequency of the simulation calculation with the actual noise generation frequency; Compare the unstable mode shape with the measured ODS mode shape; Determine the accuracy of the system simulation model from the two dimensions of the noise generation frequency and the mode shape.

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