Automobile brake jitter evaluation method and system

Abstract

The invention belongs to the technical field of automobile testing, and discloses an automobile brake jitter evaluation method and system, and the method comprises the steps: setting a plurality of working conditions, and simulating the cold state, temperature rise, high temperature, cooling and low temperature experiment processes of a whole automobile road test; and under multiple working conditions, brake shake evaluation of a low disc temperature section, a middle disc temperature section and a high disc temperature section is carried out on the vehicle, and the multiple working conditions have different vehicle speed changes, brake strengths and gears. According to the invention, automobile brake jitter evaluation is carried out by adopting different automobile speed changes, different brake intensities and different gears, so that the product development process is closer to the use condition requirements of customers, and the use conditions of the customers can be fully simulated. The method has multiple application verification dimensions, verification working conditions meet the use requirements of customers, and the test quality is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile testing, and in particular relates to an automobile braking jitter evaluation method and system. Background Art

[0002] With the continuous improvement of brake system development technology, brake friction pads have gradually extended from low metal materials to NAO ceramic materials. NAO ceramic formula brake friction pads are superior to low metal formulas in terms of braking performance, pedal feel, thermal decay, water decay, etc. However, during long-term braking wear, NAO ceramic materials have uneven wear of brake discs and pads, which leads to brake judder.

[0003] As cars become more and more popular, customers have higher and higher requirements for braking comfort. Braking is a common working condition of vehicles. Braking tremor will seriously affect the comfort and sense of security of users. At the same time, braking tremor will greatly reduce the service life of various vehicle parts. Therefore, verifying braking tremor during the development process is the top priority of braking evaluation, and how to evaluate braking tremor has become a problem that needs to be solved.

[0004] The existing brake judder evaluation only requires that the evaluation be carried out in accordance with the method of continuous braking temperature rise (neutral gear, fixed vehicle speed, fixed braking deceleration). It does not fully consider the impact of road conditions, terrain, environment, user driving habits, etc. on brake judder, and often generalizes the particular to the general. There are insufficient verification dimensions, a single state, and it does not fully meet the actual usage needs of users. Summary of the invention

[0005] In view of the above problems, the present invention provides a method and system for evaluating automobile brake jitter, which adopts the following technical solutions:

[0006] A method for evaluating automobile brake jitter comprises the following steps:

[0007] Set up multiple working conditions to simulate the cold, heating, high temperature, cooling and low temperature experimental processes of vehicle road tests;

[0008] Under multiple operating conditions, the vehicle's brake judder is evaluated in low, medium and high disc temperature ranges, wherein the multiple operating conditions have different vehicle speed changes, braking intensities and gears.

[0009] Furthermore, under multiple working conditions, the vehicle is subjected to brake judder evaluation in low disc temperature section, middle disc temperature section and high disc temperature section, including the following steps:

[0010] The vehicle travels a first distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in neutral without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated;

[0011] In the first operating condition, the vehicle's brake jitter is evaluated in low disk temperature section, middle disk temperature section and high disk temperature section in turn; the first operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a first deceleration in a neutral state to reduce the vehicle speed to a second speed, wherein the first speed is greater than the second speed.

[0012] Furthermore, under multiple working conditions, the vehicle is subjected to brake judder evaluation in low disc temperature section, middle disc temperature section and high disc temperature section, and the following steps are also included:

[0013] The vehicle travels a second distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in neutral without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated;

[0014] In the second working condition, the vehicle is subjected to brake judder evaluation in the low disc temperature section. The second working condition includes: when the vehicle is traveling at the third speed on the highway, the brake pedal is depressed at the first deceleration in the neutral state to reduce the vehicle speed to the fourth speed;

[0015] In the third working condition, the vehicle is subjected to brake judder evaluation in the middle disc temperature section, wherein the third working condition includes: when the vehicle is traveling at the fifth speed on the highway, the brake pedal is depressed at the first deceleration in the neutral state to reduce the vehicle speed to the third speed;

[0016] In the fourth operating condition, the vehicle is evaluated for brake judder in a high disc temperature section, wherein the fourth operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a second deceleration in a neutral state to reduce the vehicle speed to a second speed.

[0017] Furthermore, under multiple working conditions, the vehicle is subjected to brake judder evaluation in low disc temperature section, middle disc temperature section and high disc temperature section, and the following steps are also included:

[0018] The vehicle travels a second distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in a gear state without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated;

[0019] In the fifth working condition, the vehicle is evaluated for brake judder in the low disk temperature section, the middle disk temperature section and the high disk temperature section in sequence. The fifth working condition includes that when the vehicle is traveling on the highway at the first speed, the brake pedal is pressed at the first deceleration in the gear state to reduce the vehicle speed to the second speed;

[0020] The vehicle travels a second distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in a gear state without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated;

[0021] In the sixth working condition, the vehicle is subjected to brake judder evaluation in the low disc temperature section, wherein the sixth working condition includes: when the vehicle is traveling at the third speed on the highway, the brake pedal is pressed at the first deceleration in the gear state to reduce the vehicle speed to the fourth speed;

[0022] In the seventh working condition, the vehicle is subjected to brake judder evaluation in the middle disc temperature section, wherein the seventh working condition includes: when the vehicle is traveling at the fifth speed on the highway, the brake pedal is pressed at the first deceleration in the gear state to reduce the vehicle speed to the third speed;

[0023] In the eighth operating condition, the vehicle is evaluated for brake judder in a high disk temperature section, wherein the eighth operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a second deceleration in a gear state to reduce the vehicle speed to a second speed.

[0024] Further, the brake judder evaluation includes the following steps:

[0025] Before, after and during the vehicle road test, measure the brake disc thickness change and brake disc end face runout;

[0026] Determine whether the brake disc thickness change and brake disc end face runout are less than or equal to the set values ​​during and after the vehicle road test;

[0027] Based on the jitter evaluation index, the brake jitter is scored, and the satisfaction with the brake jitter is determined according to the scored value.

[0028] Furthermore, the jitter evaluation indicators include the degree of jitter of the vehicle body, floor, brake pedal, and steering wheel during braking, the degree of reproducibility of brake jitter, the duration of brake jitter, the vehicle speed when brake jitter occurs, the pressure range when brake jitter occurs, the brake disc temperature range when brake jitter occurs, and the frequency of brake jitter.

[0029] Furthermore, the measurement of brake disc thickness variation and brake disc end face runout is performed, including the following steps: the vehicle is not moved during measurement, and the brake disc thickness variation and brake disc end face runout are measured at multiple measurement points on both sides of the brake disc friction surface.

[0030] Furthermore, the fifth speed is greater than the first speed, and the third speed is less than the first speed.

[0031] Furthermore, the second deceleration is greater than the first deceleration.

[0032] The present invention also provides a vehicle brake jitter evaluation system, comprising:

[0033] The working condition setting module is used to set multiple working conditions to simulate the experimental process of cold state, heating, high temperature, cooling and low temperature of the whole vehicle road test;

[0034] The jitter evaluation module is used to evaluate the braking jitter of the vehicle in low disc temperature range, medium disc temperature range and high disc temperature range under multiple working conditions, wherein the multiple working conditions have different vehicle speed changes, braking intensities and gears.

[0035] Beneficial effects of the present invention:

[0036] The present invention uses different vehicle speed changes, different braking strengths, and different gears to carry out automobile brake jitter evaluation, making the product development process closer to customer usage requirements and fully simulating customer usage conditions. The present invention has multiple application verification dimensions, and the verification conditions meet customer usage requirements, greatly improving the test quality.

[0037] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram showing the main flow of a method for evaluating automobile brake jitter according to an embodiment of the present invention is shown;

[0040] Figure 2 A detailed flow chart of a method for evaluating automobile brake jitter according to an embodiment of the present invention is shown;

[0041] Figure 3 A diagram showing the arrangement of measurement points on the friction surface of a brake disc according to an embodiment of the present invention is shown;

[0042] Figure 4 A structural schematic diagram of a vehicle brake jitter evaluation system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0044] It should be noted that the terms "first", "second", etc. in the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0045] The present invention provides a method and system for evaluating automobile brake jitter, which use different vehicle speed changes, different braking intensities, and different gears to carry out automobile brake jitter evaluation. The application of the present invention has the operating characteristics of comprehensive use conditions, sufficient verification conditions, and high reliability of verification results.

[0046] like Figure 1 As shown, a method for evaluating automobile brake jitter includes the following steps: setting multiple working conditions to simulate the experimental process of cold state, heating, high temperature, cooling and low temperature of the whole vehicle road test; in the multiple working conditions, the vehicle is evaluated for brake jitter in the low disk temperature section, the middle disk temperature section and the high disk temperature section, wherein the multiple working conditions have different vehicle speed changes, braking strengths and gears, such as Figure 2 As shown, the details are as follows:

[0047] S1. The vehicle travels a first distance at a set speed on a highway. At this time, the vehicle is in a normal driving mode, and the number of braking times is minimized while ensuring safety. For example, the first distance may be 50 km.

[0048] S2. When the vehicle speed increases from the first speed to the second speed in neutral without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated, wherein the first speed is greater than the second speed, for example, the first speed may be 120 km / h, and the second speed may be 80 km / h.

[0049] S3. In the first working condition, the brake judder of the vehicle is evaluated in the low disc temperature section, the middle disc temperature section and the high disc temperature section in sequence.

[0050] The first operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a first deceleration in a neutral state to reduce the vehicle speed to a second speed.

[0051] For example, the low disk temperature section is 50-100℃, the middle disk temperature section is 100-250℃, the high disk temperature section is greater than 250℃, and the first deceleration is 1.5-2m / s 2 , the first deceleration is an indicator of braking intensity.

[0052] S4. The vehicle travels a second distance at a set speed on the highway. At this time, the vehicle is in a normal driving mode, and the number of braking times is minimized while ensuring safety. For example, the second distance is 100 km.

[0053] S5. After the vehicle speed is increased to the first speed, it glides to the second speed in neutral without braking. The non-braking vibration caused by the vehicle itself and the ground is evaluated.

[0054] S6. In the second working condition, the vehicle is subjected to brake judder evaluation in the low disc temperature section, wherein the second working condition includes: when the vehicle is driving at the third speed on the highway, the brake pedal is pressed at the first deceleration in the neutral state to reduce the vehicle speed to the fourth speed. The third speed is less than the first speed, and the fourth speed is less than the third speed. For example, the third speed is 100 km / h and the fourth speed is 60 km / h.

[0055] S7. In the third working condition, the vehicle is subjected to brake judder evaluation in the middle disc temperature range, wherein the third working condition includes: when the vehicle is driving at the fifth speed on the highway, the brake pedal is pressed at the first deceleration in the neutral state to reduce the vehicle speed to the third speed. The fifth speed is greater than the first speed, for example, the fifth speed is 140 km / h.

[0056] S8. In the fourth working condition, the vehicle is subjected to brake judder evaluation in the high disc temperature section, wherein the fourth working condition includes: when the vehicle is driving on the highway at the first speed, the brake pedal is pressed at the second deceleration in the neutral state to reduce the vehicle speed to the second speed. The second deceleration is greater than the first deceleration, for example, the second deceleration is 3m / s 2 .

[0057] The present invention characterizes the braking strength through the first deceleration and the second deceleration. The greater the deceleration value, the greater the braking strength.

[0058] In the present invention, through steps S1 to S6, the Type I test process (cold state, heating, high temperature, cooling, low temperature) is simulated, and the brake jitter evaluation is performed; compared with step S3, steps S6 to S8 perform brake jitter evaluations with different vehicle speed changes and different braking intensities, which are more in line with user usage.

[0059] S9. The vehicle travels a second distance at a set speed on the highway. At this time, the vehicle is in normal driving mode, and the number of braking times is minimized while ensuring safety.

[0060] S10, after the vehicle speed is increased to the first speed, the vehicle glides to the second speed in the gear state without braking, and non-braking vibration caused by the vehicle itself and the ground is evaluated.

[0061] For example, the gear state of an automatic transmission vehicle is D gear, and the neutral state of a manual transmission vehicle is the highest gear or the second highest gear.

[0062] S11. In the fifth operating condition, the vehicle is evaluated for brake judder in low disk temperature section, middle disk temperature section and high disk temperature section in sequence, wherein the fifth operating condition includes when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a first deceleration in a gear state to reduce the vehicle speed to a second speed.

[0063] S12. The vehicle travels a second distance at a set speed on the highway. At this time, the vehicle is in a normal driving mode, and the number of braking times is minimized while ensuring safety.

[0064] S13, after the vehicle speed is increased to the first speed, the vehicle glides to the second speed in the gear state without braking, and non-braking vibration caused by the vehicle itself and the ground is evaluated.

[0065] S14. In the sixth working condition, the vehicle is subjected to brake judder evaluation in the low disc temperature section, wherein the sixth working condition includes: when the vehicle is traveling at the third speed on the highway, the brake pedal is pressed at the first deceleration in the gear state to reduce the vehicle speed to the fourth speed. For example, the third speed is 100 km / h and the fourth speed is 60 km / h.

[0066] S15. In the seventh operating condition, the vehicle is subjected to brake judder evaluation in the middle disc temperature range, wherein the seventh operating condition includes: when the vehicle is traveling at the fifth speed on the highway, the brake pedal is depressed at the first deceleration in the gear state to reduce the vehicle speed to the third speed.

[0067] S16. In the eighth operating condition, the vehicle is subjected to brake judder evaluation in a high disk temperature section, wherein the eighth operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a second deceleration in a gear state to reduce the vehicle speed to a second speed.

[0068] In the present invention, step S9 to step S16 are used to evaluate the brake judder in the gear, which is more suitable for the user's use.

[0069] For example, brake judder evaluation includes the following steps:

[0070] S21. Before the vehicle road test, after the test and during the test, measure the change in brake disc thickness and the runout of the brake disc end face.

[0071] For example, during the vehicle road test, the brake disc thickness change and brake disc end face runout are measured every 2,000 km.

[0072] For example, the measurement of brake disc thickness variation and brake disc end face runout includes the following steps: the vehicle is not moved during measurement, and the brake disc thickness variation and brake disc end face runout are measured at multiple measurement points on both sides of the brake disc friction surface.

[0073] like Figure 3 As shown, for example, the multiple measurement points include measurement point 1 and measurement point 2 about 10 mm outward from the inner edges on both sides of the brake disc friction surface, measurement point 3 and measurement point 4 in the middle of both sides of the brake disc friction surface, and measurement point 5 and measurement point 6 about 10 mm inward from the outer edges on both sides of the brake disc friction surface.

[0074] S22. Determine whether the brake disc thickness variation and the brake disc end face runout are less than or equal to set values ​​during and after the vehicle road test.

[0075] For example, during and after the vehicle road test, the change in brake disc thickness is ≤20μm, and the brake disc end face runout is ≤70μm.

[0076] S23. Score the brake jitter based on the jitter evaluation index, and determine the satisfaction with the brake jitter according to the scored value.

[0077] For example, the jitter evaluation indicators include the degree of jitter of the vehicle body, floor, brake pedal, and steering wheel during braking, the degree of reproducibility of brake jitter, the duration of brake jitter, the vehicle speed when brake jitter occurs, the pressure range when brake jitter occurs, the brake disc temperature range when brake jitter occurs, and the frequency of brake jitter.

[0078] For example, the brake jitter is scored, and whether the brake jitter meets the requirements is determined based on the score value, as shown in Table 1. When braking, the car body, floor, brake pedal, and steering wheel shake continuously and violently, with a score of 1-2 points, and the customer is very dissatisfied; when braking, the car body, floor, brake pedal, and steering wheel shake continuously and obviously, with a score of 3-4 points, and the customer is very dissatisfied; when braking, the car body, floor, brake pedal, and steering wheel shake slightly continuously, with a score of 5 points, and the customer is slightly dissatisfied; when braking, the brake pedal and steering wheel shake slightly continuously, with a score of 6 points, and the customer is basically satisfied; when braking, the brake pedal and steering wheel occasionally shake slightly, with a score of 7 points, and the customer is basically satisfied; when braking, the brake pedal shakes slightly, with a score of 8 points, and the customer is very satisfied; when braking, the shaking is difficult to detect or no shaking is found, and the customer is very satisfied.

[0079] Table 1

[0080]

[0081] Based on the above-mentioned automobile brake jitter evaluation method, such as Figure 4As shown, the present invention also provides a vehicle brake jitter evaluation system, including a working condition setting module and a jitter evaluation module.

[0082] Among them, the working condition setting module is used to set multiple working conditions to simulate the cold, heating, high temperature, cooling and low temperature experimental processes of the whole vehicle road test.

[0083] The jitter evaluation module is used to evaluate the braking jitter of the vehicle in low disc temperature range, medium disc temperature range and high disc temperature range under multiple working conditions, wherein the multiple working conditions have different vehicle speed changes, braking intensities and gears.

[0084] The test process of the present invention and the use of different vehicle speed changes, different braking intensities, and different gears to carry out brake jitter evaluation make the product development process closer to the customer's use condition requirements and can fully simulate the customer's use conditions. The application verification of the present invention has multiple dimensions, and the verification conditions meet the customer's use requirements, which greatly improves the test quality.

[0085] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating automobile brake jitter, characterized in that: The following steps are involved: Set up multiple working conditions to simulate the cold, heating, high temperature, cooling and low temperature experimental processes of vehicle road tests; Under multiple operating conditions, the vehicle's brake judder is evaluated in low, medium and high disc temperature ranges, wherein the multiple operating conditions have different vehicle speed changes, braking intensities and gears.

2. The automobile brake judder evaluation method according to claim 1, characterized in that: Under multiple working conditions, the vehicle's brake judder is evaluated at low, medium and high disc temperatures, including the following steps: The vehicle travels a first distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in neutral without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated; In the first operating condition, the vehicle's brake jitter is evaluated in low disk temperature section, middle disk temperature section and high disk temperature section in turn; the first operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a first deceleration in a neutral state to reduce the vehicle speed to a second speed, wherein the first speed is greater than the second speed.

3. The automobile brake judder evaluation method according to claim 2, characterized in that: Under multiple working conditions, the vehicle is subjected to brake judder evaluation at low, medium and high disc temperatures, and the following steps are also included: The vehicle travels a second distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in neutral without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated; In the second working condition, the vehicle is subjected to brake judder evaluation in the low disc temperature section. The second working condition includes: when the vehicle is traveling at the third speed on the highway, the brake pedal is depressed at the first deceleration in the neutral state to reduce the vehicle speed to the fourth speed; In the third working condition, the vehicle is subjected to brake judder evaluation in the middle disc temperature section, wherein the third working condition includes: when the vehicle is traveling at the fifth speed on the highway, the brake pedal is depressed at the first deceleration in the neutral state to reduce the vehicle speed to the third speed; In the fourth operating condition, the vehicle is evaluated for brake judder in a high disc temperature section, wherein the fourth operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a second deceleration in a neutral state to reduce the vehicle speed to a second speed.

4. The automobile brake judder evaluation method according to claim 3, characterized in that: Under multiple working conditions, the vehicle is subjected to brake judder evaluation at low, medium and high disc temperatures, and the following steps are also included: The vehicle travels a second distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in a gear state without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated; In the fifth working condition, the vehicle is evaluated for brake judder in the low disk temperature section, the middle disk temperature section and the high disk temperature section in sequence. The fifth working condition includes that when the vehicle is traveling on the highway at the first speed, the brake pedal is pressed at the first deceleration in the gear state to reduce the vehicle speed to the second speed; The vehicle travels a second distance at a set speed on a highway, and when the vehicle speed increases to the first speed and then glides to the second speed in a gear state without braking, the non-braking vibration caused by the vehicle itself and the ground is evaluated; In the sixth working condition, the vehicle is subjected to brake judder evaluation in the low disc temperature section, wherein the sixth working condition includes: when the vehicle is traveling at the third speed on the highway, the brake pedal is pressed at the first deceleration in the gear state to reduce the vehicle speed to the fourth speed; In the seventh working condition, the vehicle is subjected to brake judder evaluation in the middle disc temperature section, wherein the seventh working condition includes: when the vehicle is traveling at the fifth speed on the highway, the brake pedal is pressed at the first deceleration in the gear state to reduce the vehicle speed to the third speed; In the eighth operating condition, the vehicle is evaluated for brake judder in a high disk temperature section, wherein the eighth operating condition includes: when the vehicle is traveling at a first speed on a highway, the brake pedal is depressed at a second deceleration in a gear state to reduce the vehicle speed to a second speed.

5. The automobile brake jitter evaluation method according to any one of claims 1 to 4, characterized in that: Brake judder evaluation includes the following steps: Before, after and during the vehicle road test, measure the brake disc thickness change and brake disc end face runout; Determine whether the brake disc thickness change and brake disc end face runout are less than or equal to the set values ​​during and after the vehicle road test; Based on the jitter evaluation index, the brake jitter is scored, and the satisfaction with the brake jitter is determined according to the scored value.

6. The automobile brake judder evaluation method according to claim 5, characterized in that: The jitter evaluation indicators include the degree of jitter of the vehicle body, floor, brake pedal, and steering wheel during braking, the degree of reproducibility of brake jitter, the duration of brake jitter, the vehicle speed when brake jitter occurs, the pressure range when brake jitter occurs, the brake disc temperature range when brake jitter occurs, and the frequency of brake jitter.

7. The automobile brake judder evaluation method according to claim 5, characterized in that: The measurement of brake disc thickness variation and brake disc end face runout includes the following steps: the vehicle is not moved during measurement, and the brake disc thickness variation and brake disc end face runout are measured at multiple measurement points on both sides of the brake disc friction surface.

8. The automobile brake judder evaluation method according to claim 4, characterized in that: The fifth speed is greater than the first speed, and the third speed is less than the first speed.

9. The automobile brake judder evaluation method according to claim 4, characterized in that: The second deceleration is greater than the first deceleration.

10. An automobile brake jitter evaluation system, characterized in that: include: The working condition setting module is used to set multiple working conditions to simulate the experimental process of cold state, heating, high temperature, cooling and low temperature of the whole vehicle road test; The jitter evaluation module is used to evaluate the braking jitter of the vehicle in low disc temperature range, medium disc temperature range and high disc temperature range under multiple working conditions, wherein the multiple working conditions have different vehicle speed changes, braking intensities and gears.

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