Brake sound acquisition method, device and system

Abstract

The embodiment of the application discloses a brake sound acquisition method, device and system, and belongs to the technical field of vehicle testing. The method comprises the following steps: setting a test environment by controlling an environment bin, wherein the test environment comprises environmental humidity and environmental temperature; controlling a driving motor to output torque and controlling a brake caliper of a hydraulic brake to brake under the test environment based on a test working condition, wherein the test working condition is used for simulating a working condition of a vehicle starting on a slope; and acquiring brake sound collected by a microphone in the case that the state of a brake disc meets the test working condition, wherein the brake sound is generated by friction between a brake pad to be tested and the brake disc. The technical scheme provided by the embodiment of the application can improve the accuracy of the brake sound acquisition result.

Description

Technical Field

[0001] This application relates to the field of vehicle testing technology, and in particular to a braking sound acquisition method, device and system. Background Technology

[0002] The noise level during vehicle start-up and braking (groan noise) has a significant impact on the comfort of vehicle use. Related technologies involve manually operating the vehicle at low speeds and having the driver subjectively evaluate the braking sound.

[0003] However, the whole vehicle Groan sound test is conducted outdoors, which is greatly affected by the ambient temperature and humidity, and can easily lead to deviations in the results of the brake sound collection. Summary of the Invention

[0004] This application provides a braking sound acquisition method, device, and system, the technical solution of which includes the following contents.

[0005] On one hand, this application provides a braking sound acquisition method for a braking sound acquisition system. The braking sound acquisition system includes: a suspension, a hydraulic brake, a drive motor, a microphone, an environmental chamber, and a control console. The hydraulic brake is mounted on the suspension, and the suspension and the hydraulic brake are mounted in the environmental chamber. The torque output end of the drive motor is connected to the brake disc of the hydraulic brake via a connecting shaft. The brake caliper of the hydraulic brake is equipped with a brake pad to be tested. The control console is connected to the environmental chamber, the hydraulic brake, the drive motor, and the microphone.

[0006] The method is executed by the console in the brake sound acquisition system, and the method includes:

[0007] The environmental chamber is controlled to set up the test environment, which includes ambient humidity and ambient temperature.

[0008] Under the test environment, the drive motor is controlled to output torque based on the test conditions, and the brake caliper of the hydraulic brake is controlled to brake. The test conditions are used to simulate the conditions when the vehicle starts on a slope.

[0009] When the brake disc is in a condition that meets the test conditions, the braking sound collected by the microphone is obtained. The braking sound is generated by the friction between the brake pad under test and the brake disc.

[0010] On the other hand, embodiments of this application provide a braking sound acquisition device, the device comprising:

[0011] An environmental control module is used to control the setting of the test environment in the environmental chamber, the test environment including ambient humidity and ambient temperature;

[0012] The working condition control module is used to control the drive motor to output torque based on the test working condition under the test environment, and to control the brake caliper of the hydraulic brake to brake, wherein the test working condition is used to simulate the working condition of the vehicle when starting on a slope.

[0013] The acquisition module is used to acquire the braking sound collected by the microphone when the brake disc is in a condition that meets the test conditions. The braking sound is generated by the friction between the brake pad under test at the brake caliper and the brake disc.

[0014] On the other hand, embodiments of this application provide a braking sound acquisition system, the braking sound acquisition system comprising:

[0015] The system includes a suspension, a hydraulic brake, a drive motor, a microphone, an environmental chamber, and a control console. The hydraulic brake is mounted on the suspension, and the suspension and the hydraulic brake are located in the environmental chamber. The torque output end of the drive motor is connected to the brake disc of the hydraulic brake via a connecting shaft. The brake caliper of the hydraulic brake is equipped with a brake pad to be tested. The control console is connected to the environmental chamber, the hydraulic brake, the drive motor, and the microphone.

[0016] The console is used to control the environmental chamber to set the test environment, which includes ambient humidity and ambient temperature;

[0017] The console is also used to control the drive motor to output torque based on the test conditions in the test environment, and to control the brake caliper of the hydraulic brake to brake, wherein the test conditions are used to simulate the conditions when the vehicle starts on a slope.

[0018] The control console is also used to acquire the braking sound collected by the microphone when the brake disc is in the condition that the test conditions are met. The braking sound is generated by the friction between the brake pad under test and the brake disc.

[0019] In related technologies, braking sounds are generated by manually controlling a vehicle to creep at low speed, and then the braking sounds are subjectively evaluated. This method is easily affected by environmental factors, leading to biased results.

[0020] In this embodiment, the control console can adjust the ambient temperature and humidity of the environment where the brake pads are located through the environmental chamber, so as to avoid the influence of changes in ambient temperature and humidity on the acquisition results. The control console can also simulate the working conditions of a vehicle starting on a slope by controlling the brake calipers of the drive motor and hydraulic brake, and collect the braking sound generated by the friction between the brake pads and the brake disc, which helps to reduce the result deviation caused by human error. In summary, the technical solution provided by this embodiment can improve the accuracy of the brake sound acquisition results. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a braking sound acquisition system provided in an exemplary embodiment of this application;

[0022] Figure 2 This is a schematic diagram of the structure of a suspension angle module with brake assembly provided in an exemplary embodiment of this application;

[0023] Figure 3 This is a flowchart of a braking sound acquisition method provided in an exemplary embodiment of this application;

[0024] Figure 4 A flowchart is shown showing the control process for controlling the drive motor to output torque.

[0025] Figure 5 A flowchart illustrating the control process of controlling the brake caliper braking of a hydraulic brake is shown.

[0026] Figure 6 This is a flowchart of a braking sound acquisition method provided in another exemplary embodiment of this application;

[0027] Figure 7 This is a structural block diagram of a braking sound acquisition device provided in an exemplary embodiment of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0029] The following section will first explain some of the technical terms used in this application.

[0030] Hydraulic brakes: Brakes that use hydraulic pressure to control the brake calipers. When the driver presses the brake pedal, the pressure of the brake fluid changes, causing the brake calipers to engage.

[0031] Brake calipers: Components installed in the braking system that press the brake pads against the brake disc under the pressure of brake fluid to achieve a braking effect.

[0032] Brake pads: In a vehicle's braking system, these are the components that perform the braking function. The quality of the brake pads plays a decisive role in the braking effect.

[0033] Braking noise: also known as groan noise, is produced by the friction and vibration between brake pads when the vehicle is slowly starting or stopping.

[0034] Brake fluid: A liquid with incompressible properties that, when subjected to pressure within a sealed container, can transmit pressure to all parts of the liquid to achieve hydraulic braking.

[0035] Groan noise during vehicle start-up (braking noise) has a significant impact on vehicle comfort. Currently, groan noise testing is conducted manually on the vehicle, on flat and sloping roads, where the driver controls the vehicle speed and brake fluid by pressing the brake pedal to maintain a very low crawling motion forward or backward, and then subjectively evaluates the groan noise under these conditions.

[0036] However, the whole vehicle Groan sound test is conducted outdoors, which is greatly affected by the ambient temperature and humidity, and can easily lead to deviations in the brake sound acquisition results.

[0037] This application provides a braking sound acquisition method. The method simulates the working conditions of a vehicle starting on a slope in the braking sound acquisition system, and controls the ambient temperature and humidity through an environmental chamber to reduce the impact of the test environment on the brake pads, thereby improving the accuracy of the acquisition results.

[0038] See Figure 1 , Figure 1 This is a schematic diagram of the structure of a braking sound acquisition system provided in an exemplary embodiment of this application. The braking sound acquisition system includes: a hydraulic brake 101, a suspension 102, an environmental chamber 103, a drive motor 104, a control console 105, and a microphone 106.

[0039] The hydraulic brake 101 is mounted on the suspension 102, and the suspension 102 and the hydraulic brake 101 are housed in the environmental chamber 103. The torque output end of the drive motor 104 is connected to the brake disc of the hydraulic brake 101 via a connecting shaft. The brake caliper of the hydraulic brake 101 is equipped with the brake pad to be tested. The control console 105 is connected to the environmental chamber 103, the hydraulic brake 101, the drive motor 104, and the microphone 106.

[0040] The braking principle of the hydraulic brake 101 is to increase the pressure of the brake fluid inside the pipeline (brake hydraulic pressure) and transmit the pressure to the brake caliper of the hydraulic brake 101, so that the brake pads on the brake caliper contact the brake disc of the hydraulic brake 101, preventing the brake disc from rotating, thereby achieving the braking effect.

[0041] Optionally, the braking hydraulic pressure of the hydraulic brake 101 can be controlled by an additional hydraulic pressurization module (not shown in the figure) to simulate the actual use of the hydraulic brake 101 in a vehicle.

[0042] The suspension 102 is used to support the hydraulic brake 101, making it easy to connect the hydraulic brake 101 to other devices so as to simulate the arrangement of the hydraulic brake 101 on the whole vehicle.

[0043] The environmental chamber 103 is used to control the environment in which the brake pads under test are located, thereby reducing the impact of the environment on the test results.

[0044] The drive motor 104 is used to drive the brake disc of the hydraulic brake 101 to rotate. Since the drive motor 104 and the brake disc of the hydraulic brake 101 are connected by a connecting shaft, the speed of the brake disc is the same as the speed of the motor. A speed sensor for measuring the motor speed can be set on this connecting shaft. Optionally, the drive motor 104 can be a servo motor.

[0045] Because the pressure applied to the brake disc by the brake caliper of the hydraulic brake 101 is controlled by the brake hydraulic fluid, the braking torque of the hydraulic brake 101 is not the same as the motor torque output by the drive motor 104. When the motor torque is less than the braking torque, the brake disc decelerates.

[0046] The control console 105 is used to control the environmental chamber 103 to set the test environment, which includes ambient humidity and ambient temperature; it is also used to control the drive motor 104 to output torque based on the test conditions under the test environment, and to control the brake caliper of the hydraulic brake 101 to brake, the test conditions being used to simulate the vehicle's condition when starting on a slope; it is also used to acquire the braking sound collected by the microphone 106 when the brake disc is in a condition that meets the test conditions, the braking sound being generated by the friction between the brake pads under test and the brake disc.

[0047] In order to improve the accuracy of the data collection, additional components and tooling are required to connect the hydraulic brake 101 and the suspension 102 in the environmental chamber 103 so that the test conditions match the actual usage conditions on the vehicle.

[0048] See Figure 2 , Figure 2 This is a schematic diagram of a suspension angle module with brake assembly provided in an exemplary embodiment of this application. The suspension angle module with brake assembly is located within an environmental chamber and includes a suspension 201, a suspension spring 202, a shock absorber 203, a hydraulic brake 204, and other tooling. The suspension 201 is connected to the suspension spring 202, the suspension spring 202 is connected to the shock absorber 203, the shock absorber 203 is connected to the hydraulic brake 204, and the other tooling supports the aforementioned connection structure.

[0049] In the hydraulic brake, the brake caliper 205 contacts the surface of the brake disc 206 when the brake hydraulic pressure increases, and separates from the brake disc 206 when the brake hydraulic pressure decreases. The rotation axis of the hydraulic brake 204 is coaxial with the torque output end of the drive motor.

[0050] The vehicle has four wheels, each of which can correspond to a hydraulic brake 204. (This is from an embodiment of the application.) Figure 2The connection of a single hydraulic brake 204 within the environmental chamber is shown. Optionally, the brake sound acquisition system may include four hydraulic brakes 204 for synchronous testing with four brake pads as a group, or the number of hydraulic brakes 204 within the brake sound acquisition system may be adjusted based on actual testing requirements.

[0051] See Figure 3 , Figure 3 This is a flowchart of a braking sound acquisition method provided in an exemplary embodiment of this application. In this embodiment, the braking sound acquisition method is executed by a console in a braking sound acquisition system. The method includes the following steps.

[0052] Step 301: Control the environment chamber to set up the test environment, which includes ambient humidity and ambient temperature.

[0053] In one possible implementation, the console reads the ambient temperature and humidity corresponding to the test conditions, and then instructs the environmental chamber to adjust the temperature and humidity to the corresponding ambient temperature and humidity.

[0054] Optionally, the control console can pre-set the test environment in the environmental chamber before testing the brake pads, and then maintain the ambient temperature and humidity for a fixed period of time, so that the brake pads to be tested are fully affected by the ambient temperature and humidity, before executing step 302. For example, the control console controls the environmental chamber to maintain the ambient temperature and humidity, so that the hydraulic brake with the brake pads to be tested is placed in the environmental chamber overnight.

[0055] Step 302: In the test environment, the drive motor is controlled to output torque based on the test conditions, and the brake calipers of the hydraulic brake are controlled to brake. The test conditions are used to simulate the conditions when the vehicle starts on a slope.

[0056] In some embodiments, the drive motor simulates the downward rolling tendency of a vehicle due to gravity on a slope by outputting torque. Since the vehicle's rolling tendency when starting on a slope is affected by various factors, such as the slope gradient and vehicle weight, various test conditions exist. The motor torque output by the drive motor varies under different test conditions.

[0057] In some possible test scenarios, the control console first controls the hydraulic brake calipers to increase braking torque and controls the drive motor to output torque. The braking torque of the hydraulic brake is greater than the motor torque output by the drive motor, ensuring the brake disc remains stable (zero rotation speed) to simulate the brake disc state when the vehicle is parked on a slope. Then, the control console slowly releases the brake calipers, causing the drive motor to begin rotating the brake disc, simulating the vehicle's transition from parking to starting.

[0058] Optionally, the control console controls the brake calipers by controlling the brake hydraulic pressure. The brake hydraulic pressure is positively correlated with the braking torque of the brake.

[0059] It should be noted that the simulated vehicle hill start condition (test condition) in this application embodiment does not refer to the uphill start condition where the engine provides power to overcome gravity and climb the hill, but rather to the dismount start condition controlled by the brake pedal. The control console only needs to control the brake calipers of the hydraulic brake to obtain the braking sound when the vehicle starts, without the need for additional devices or tooling to simulate the situation where the engine provides power to start the vehicle.

[0060] Furthermore, the test conditions simulate the vehicle's start-up on an incline, which can extend the duration of the braking sound by reducing the starting speed, thus enabling accurate identification of the braking sound. In contrast, the braking sound when the vehicle comes to a stop is generated when the brake pedal is slammed on while the vehicle is moving, resulting in a braking sound that is too short and difficult to control. Since the braking sound when the vehicle comes to a stop and the braking sound when the vehicle starts are caused by the same factors, this embodiment of the application obtains the braking sound by simulating the vehicle's start-up on an incline.

[0061] Step 303: Under the condition that the brake disc is in the same condition as the test, the braking sound collected by the microphone is obtained. The braking sound is generated by the friction between the brake pad under test and the brake disc.

[0062] The test condition is used to simulate the vehicle's operation when starting on a slope. Under this condition, the vehicle is in a state of slow forward creeping, that is, in a critical state between a stationary state and a forward moving state. Correspondingly, the brake disc is in a state of vibration with a rotational tendency.

[0063] In some embodiments, the brake disc is in a state consistent with the test conditions, meaning it is in a critical state about to disengage from the brake caliper. In this critical state, the friction type between the brake pads and the brake disc alternates between dynamic and static friction, causing the brake disc to vibrate. In this embodiment, the control console controls the drive motor to output torque and controls the brake caliper of the hydraulic brake to bring the brake disc under test into the aforementioned critical state, generating a braking sound.

[0064] In some embodiments, a microphone is positioned around the brake to capture braking sounds.

[0065] In this embodiment, the control console can adjust the ambient temperature and humidity of the environment where the brake pads are located through the environmental chamber, so as to avoid the impact of changes in ambient temperature and humidity on the acquisition results. The control console can also simulate the working conditions of a vehicle starting on a slope by controlling the brake calipers of the drive motor and hydraulic brake, and collect the braking sound generated by the friction between the brake pads and the brake disc, which helps to reduce the result deviation caused by human error. In summary, the technical solution provided by this embodiment can improve the accuracy of the brake sound acquisition results.

[0066] In some embodiments, the vehicle parameters and slope angles differ under different test conditions. These vehicle parameters and slope angles affect the braking torque of the hydraulic brakes.

[0067] See Figure 4 , Figure 4 A flowchart illustrating the control process for controlling the drive motor to output torque is shown. This process includes the following steps.

[0068] 3021A, based on the vehicle parameters and slope angle under test conditions, determines the parking braking torque corresponding to the slope angle. The parking braking torque is the minimum braking torque required for parking on a slope.

[0069] Optionally, vehicle parameters may include vehicle weight, vehicle roll radius, etc., where vehicle weight can be determined based on vehicle mass and gravity coefficient.

[0070] For example, the method for determining the parking braking torque is shown in Formula 1:

[0071] Formula 1: T1 = mg * sin(a) * R / 2

[0072] Where T1 is the parking braking torque (in Nm), m is the vehicle mass (in kg), g is the gravity coefficient, mg is the vehicle weight, a is the slope angle, and R is the vehicle rolling radius (in m).

[0073] In some embodiments, the vehicle is prone to sliding due to gravity, and the parking braking torque of the hydraulic brake is the minimum braking torque required to overcome this sliding tendency and ensure that the vehicle comes to a stop.

[0074] 3021B, determining the motor torque of the drive motor under test conditions based on the parking braking torque.

[0075] Since the parking braking torque is the minimum braking torque required for parking on a slope, using the same amount of torque can simulate the downward slipping tendency of a vehicle under the influence of gravity under the same working conditions, so that the brake disc has a rotational tendency similar to that of a vehicle when it is slipping downhill.

[0076] In some embodiments, the controller sets the motor torque to the same magnitude as the parking braking torque, outputs the motor torque by driving the motor, and applies it to the brake disc, so that the brake disc has a rotational tendency when the vehicle rolls downhill.

[0077] 3021C is a motor torque control drive motor for torque output.

[0078] In one possible implementation, the control console adjusts the current or voltage of the drive motor to cause the drive motor to output the motor torque.

[0079] In another possible implementation, the console sends a torque setting command to the drive motor to set the motor torque.

[0080] In some embodiments, the console controls the braking of the brake calipers by controlling the brake hydraulic pressure.

[0081] See Figure 5 , Figure 5 A flowchart illustrating the control process for controlling the brake caliper of a hydraulic brake is shown. This process includes the following steps.

[0082] 3022A, based on the parking braking torque and the brake parameters of the hydraulic brake, determines the brake hydraulic pressure.

[0083] Optionally, the braking fluid pressure is positively correlated with the braking torque generated by the hydraulic brake. When the braking fluid pressure increases, the braking torque increases; when the braking fluid pressure decreases, the braking torque decreases.

[0084] To simulate the vehicle's transition from parking to starting on a slope, the brake hydraulic pressure needs to be greater than or equal to the hydraulic pressure required to generate the parking braking torque. Specifically, when the hydraulic brake torque is greater than the parking braking torque, the vehicle remains stably parked on the slope. As the vehicle transitions from a parking to a starting state on the slope, the braking torque generated by the hydraulic brake gradually decreases, and the brake hydraulic pressure gradually drops. When the hydraulic brake torque equals the parking braking torque, the vehicle exhibits a tendency to start on a downhill slope.

[0085] As can be deduced from the above reasoning, under test conditions, when the braking torque generated by the hydraulic brake is equal to the braking hydraulic pressure corresponding to the parking braking torque, the brake disc tends to rotate.

[0086] Optionally, the brake parameters of the hydraulic brake may include the front brake caliper cylinder diameter, the effective braking radius of the front wheel, the front braking friction coefficient, the rear brake caliper cylinder diameter, the effective braking radius of the rear wheel, and the rear braking friction coefficient.

[0087] For example, the braking torque generated by a hydraulic brake is determined as shown in Formula 2:

[0088] Formula 2: T2 = P * (D1 / 2) 2 *π*r1*u1*4+P*(D2 / 2) 2 *π*r²*u²*4

[0089] Where T2 is the braking torque generated by the hydraulic brake (in Nm), P is the brake hydraulic pressure (in Pa), D1 is the front brake caliper cylinder diameter (in m), r1 is the effective braking radius of the front wheel (in m), u1 is the front brake friction coefficient, D2 is the rear brake caliper cylinder diameter (in m), r2 is the effective braking radius of the rear wheel (in m), and u2 is the rear brake friction coefficient. With the parking braking torque T1 determined, the control console, based on the tendency of the brake disc to rotate when T1 = T2 (used to simulate the vehicle's downhill start tendency), substitutes the parking braking torque into Formula 2 to determine the brake hydraulic pressure P.

[0090] 3022B, based on brake hydraulic control brake caliper braking.

[0091] In some possible implementations, the control console first controls the pressure of the hydraulic fluid to exceed the brake fluid pressure, allowing the brake disc to remain stationary while the drive motor outputs its torque. After the brake fluid pressure is continuously increased for a period of time, the control console controls the brake fluid pressure to slowly decrease until the brake disc's condition meets the test requirements.

[0092] It should be noted that, due to the error in the coefficient of friction, the control console cannot directly control the brake caliper to brake and make the brake disc state meet the test conditions by setting the brake hydraulic pressure. Instead, the brake fluid pressure needs to exceed the brake hydraulic pressure first, and then the state of the brake disc is determined during the hydraulic pressure drop.

[0093] In one exemplary example, the controller sets the brake hydraulic pressure, then applies hydraulic pressure for approximately 20 seconds until the brake fluid pressure exceeds the set brake hydraulic pressure. After 20 seconds, the hydraulic pressure is released to determine if the brake disc condition meets the test conditions. If the test conditions are met, the braking sound collected by the microphone is acquired.

[0094] In this embodiment, the control console determines the motor torque based on the parking brake torque, enabling the drive motor to simulate the downward slipping trend of the vehicle under gravity during parking on a slope. Furthermore, the control console determines the brake hydraulic pressure based on the parking brake torque to adjust the brake calipers of the hydraulic brake, ensuring that the brake disc is in a state consistent with the test conditions. This improves the efficiency of the control console in controlling the brake disc to enter a state consistent with the test conditions, allowing the microphone to quickly capture the braking sound.

[0095] In some embodiments, to prolong the duration of the braking sound for more accurate identification, the control console can control the motor speed. The braking sound captured by the microphone can be used to test the brake pads.

[0096] See Figure 6 , Figure 6 This is a flowchart of a braking sound acquisition method provided in another exemplary embodiment of this application. The method includes the following steps.

[0097] Step 601: Control the environment chamber to set up the test environment, which includes ambient humidity and ambient temperature.

[0098] Step 602: In the test environment, the drive motor is controlled to output torque based on the test conditions, and the brake calipers of the hydraulic brake are controlled to brake. The test conditions are used to simulate the conditions when the vehicle starts on a slope.

[0099] For a detailed description of steps 601 and 602, please refer to steps 301 and 302. The specific details of these steps will not be repeated in this embodiment.

[0100] Step 603: Obtain the motor speed of the drive motor.

[0101] Optionally, a speed sensor is installed on the connecting shaft between the hydraulic brake and the drive motor to measure the motor speed, which is the same as the brake disc speed. The control console receives the motor speed data acquired by the speed sensor.

[0102] Step 604: Determine whether the condition of the brake disc meets the test conditions based on the motor speed.

[0103] In some embodiments, when the brake disc is in a condition that meets the test conditions, the motor speed is approximately zero.

[0104] Optionally, the control console determines that the brake disc condition meets the test conditions if the motor speed is less than the upper limit of the speed under the test conditions.

[0105] It should be noted that the upper limit of the motor's speed corresponds to the vehicle's speed range when crawling forward at low speeds. For example, the motor speed is ≤3 r / min.

[0106] In one exemplary case, the upper limit of the rotational speed is 3 r / min. When the motor speed is less than 3 r / min, the control console determines that the state of the brake disc meets the test conditions and can collect the braking sound.

[0107] Optionally, the control panel can determine that the brake disc's condition does not meet the test conditions if the motor speed exceeds the upper limit of the test speed.

[0108] In one exemplary case, the maximum speed limit is 3 r / min. When the motor speed is greater than 3 r / min, the control console determines that the state of the brake disc does not meet the test conditions and needs to adjust the state of the brake disc in order to collect the braking sound.

[0109] The following explains how to adjust the brake disc status using the control console.

[0110] Optionally, when the motor speed exceeds the upper limit of the test operating conditions, the control console increases the brake hydraulic pressure based on the pressure increase step size. The pressure increase step size characterizes the pressure increase rate, i.e., the amount of increase in brake hydraulic pressure per second.

[0111] Since there is a positive correlation between brake hydraulic pressure and braking torque, when brake hydraulic pressure increases, braking torque increases, thus the speed of the brake disc gradually decreases, and the speed of the drive motor coaxial with the brake disc gradually decreases as well.

[0112] For example, the control console increases the brake hydraulic pressure by 0.5 bar in the first second when the motor speed is greater than the upper speed limit, and then increases it by another 0.5 bar in the second second... until the motor speed is less than the upper speed limit under the test conditions.

[0113] Optionally, if the motor speed is lower than the upper speed limit under test conditions, the control console maintains the brake fluid pressure for a set duration to prevent the motor speed from exceeding the upper speed limit, so that the microphone can collect braking sounds. For example, the control console controls the brake fluid to remain at the upper speed limit for 10 seconds when the motor speed is lower than the upper speed limit under test conditions.

[0114] Step 605: Under the condition that the brake disc is in the same condition as the test, the braking sound collected by the microphone is obtained. The braking sound is generated by the friction between the brake pad under test and the brake disc.

[0115] For a detailed explanation of step 605, please refer to step 303; the specific details will not be repeated in this embodiment.

[0116] Step 606: Determine the brake pad test results based on the braking sound under different test conditions and test environments.

[0117] Optionally, the console can repeat the test a fixed number of times under the same test conditions and environment, such as 3 times, to improve the accuracy of the brake pad test results.

[0118] Optionally, the console can test brake pads under different test conditions in the same test environment, or test brake pads under the same test conditions in different test environments.

[0119] Regarding the determination of brake pad test results, optionally, the control console can determine that the brake pad passes the test if the sound pressure level of the braking sound is below the sound pressure threshold, and determine that the brake pad fails the test if the sound pressure level of the braking sound is above the sound pressure threshold. Optionally, the brake pad test results can also be determined in conjunction with the subjective evaluation results of technical experts. Optionally, the brake pad test results can also be determined based on the output results of a machine learning model.

[0120] In this embodiment, the control console determines whether the brake disc meets the test conditions based on the motor speed, so that the braking sound collected by the microphone can be acquired when the conditions are met. Since the braking sound produced by the same brake pad may differ at different motor speeds, the control console determines the timing of brake sound acquisition based on the motor speed, which helps improve the accuracy of the brake sound acquisition results.

[0121] The control console provides a unified standard for the timing of brake sound acquisition. Specifically, when the motor speed is less than the upper limit of the test speed, the state of the brake disc is determined to be in line with the test conditions. This ensures that the motor speed is consistent with the low-speed forward creeping state of the vehicle and reduces the impact of motor speed on brake sound.

[0122] If the above standards are not met, the control console can increase the braking hydraulic pressure to make the motor speed less than the upper limit of the speed under the test conditions. This helps the control console maintain a stable motor speed, prolongs the time for the microphone to collect braking sounds, and improves the accuracy of the braking sound collection results.

[0123] By collecting braking sounds under different test conditions and environments, the accuracy of brake pad test results can be improved.

[0124] In some embodiments, the testing environment inside the environment chamber may be affected by the external environment. For example, if the external ambient temperature rises, the ambient temperature inside the environment chamber will also rise. To maintain a stable testing environment, the console needs to adjust the testing environment inside the environment chamber in real time.

[0125] Optionally, during the testing process, the console first obtains the real-time environment parameters in the environment repository, and then controls the environment repository to adjust the test environment based on the real-time environment parameters to keep the test environment stable.

[0126] Optionally, real-time environmental parameters may include the ambient temperature collected by the temperature sensor inside the environmental chamber and the ambient humidity collected by the humidity sensor.

[0127] In one possible implementation, if the ambient temperature is higher than the temperature set by the control console, the control console controls the air conditioning system inside the environmental chamber to lower the ambient temperature. If the ambient humidity is higher than the humidity set by the control console, the control console controls the air conditioning system inside the environmental chamber to lower the ambient humidity.

[0128] In another possible implementation, if the ambient temperature is lower than the temperature set by the control console, the control console controls the air conditioning system inside the environmental chamber to raise the ambient temperature. If the ambient humidity is lower than the humidity set by the control console, the control console controls the air conditioning system inside the environmental chamber to raise the ambient humidity.

[0129] In this embodiment, the control console can adjust the test environment in real time according to real-time environmental parameters, which helps to stabilize the test environment and improve the accuracy of brake pad test results during the test.

[0130] In some embodiments, the console may determine the brake pad test result of the brake pad to be tested in the following manner.

[0131] Method 1: Generate the braking sound pressure curve of the brake pad to be tested. This method includes the following two steps.

[0132] Step 1: Based on the test condition parameters, environmental parameters of the test environment, and sound pressure parameters of the braking sound, generate the braking sound pressure curve of the brake pad to be tested. The braking sound pressure curve is used to characterize the correspondence between the test conditions, the test environment, and the sound pressure parameters.

[0133] Optionally, the environmental parameters of the test environment may include ambient temperature and ambient humidity, the test condition parameters may include vehicle parameters, slope angle and brake parameters, and the sound pressure parameters of the braking sound may include sound pressure and sound pressure level.

[0134] In some embodiments, the braking sound pressure curve can characterize the changes in the braking sound pressure parameters under different test conditions and in different test environments.

[0135] Step 2: Determine the brake pad test results based on the brake sound pressure curve.

[0136] Different brake pads correspond to different braking sound pressure curves.

[0137] Optionally, the console can also display the braking sound pressure curves of different brake pads, and then determine the brake pad test results based on the evaluation of the braking sound pressure curves by technical experts.

[0138] Optionally, the console can also compare the braking sound pressure curves of different brake pads and then determine the brake pad test results.

[0139] Method 2: The brake sound evaluation model outputs the brake pad test results. This method includes the following two steps.

[0140] Step 1: Combine the test condition parameters, environmental parameters of the test environment, and sound pressure parameters of the braking sound under different test conditions to obtain the brake pad data of the brake pad to be tested.

[0141] Optionally, the environmental parameters of the test environment may include ambient temperature and ambient humidity, the test condition parameters may include vehicle parameters, slope angle and brake parameters, and the sound pressure parameters of the braking sound may include sound pressure and sound pressure level.

[0142] In an exemplary example, the ambient temperature in the environmental parameters is 20℃, the slope angle in the test conditions is 2°, and the braking sound pressure is 0.75dB. Then the brake pad data of the brake pad to be tested is 20℃|2°|0.75dB.

[0143] Step 2: Input the brake pad data into the brake pad evaluation model to obtain the brake pad test results output by the brake sound evaluation model. The brake pad evaluation model is trained based on the sample brake pad data and the sample brake pad test results of the sample brake pads.

[0144] Optionally, the console can perform vectorization representation of the spliced ​​brake pad data, or it can first perform vectorization representation of each parameter among the test condition parameters, test environment parameters, and brake sound sound pressure parameters, and then obtain the feature vector representing the brake pad data through vector splicing. The console then inputs the vectorized brake pad data into the brake pad evaluation model.

[0145] Optionally, the sample brake pad data and sample brake pad test results can be determined based on the subjective evaluation of the vehicle driver.

[0146] Optionally, the brake pad evaluation model can be a classification model, where the classification result is the brake pad test result output by the brake sound evaluation model. For example, if the brake sound evaluation model outputs 1, it indicates that the brake pad has passed the test; if the brake sound evaluation model outputs 0, it indicates that the brake pad has failed the test.

[0147] In this embodiment, the console can determine the brake pad test result by generating a brake sound pressure curve, thereby improving the efficiency of determining the brake pad test result.

[0148] The console can also determine the brake pad test results based on the output of the brake pad evaluation model, reducing the impact of errors caused by human evaluation and improving the accuracy of brake pad test results.

[0149] See Figure 7 , Figure 7 This is a structural block diagram of a braking sound acquisition device provided in an exemplary embodiment of this application. The device includes the following modules.

[0150] The environmental control module 701 is used to control the setting of the test environment in the environmental chamber, the test environment including environmental humidity and environmental temperature;

[0151] The working condition control module 702 is used to control the drive motor to output torque based on the test working condition under the test environment, and to control the brake caliper of the hydraulic brake to brake, wherein the test working condition is used to simulate the working condition of the vehicle when starting on a slope.

[0152] The acquisition module 703 is used to acquire the braking sound collected by the microphone when the brake disc is in a condition that meets the test conditions. The braking sound is generated by the friction between the brake pad under test at the brake caliper and the brake disc.

[0153] Optionally, the operating condition control module 702 is further configured to:

[0154] Based on the vehicle parameters and slope angle under the test conditions, the parking braking torque corresponding to the slope angle is determined, and the parking braking torque is the minimum braking torque required for parking on a slope.

[0155] The motor torque of the drive motor under the test condition is determined based on the parking braking torque.

[0156] The drive motor outputs torque based on the motor torque control;

[0157] The operating condition control module 702 is also used for:

[0158] Based on the parking braking torque and the brake parameters of the hydraulic brake, the braking hydraulic pressure is determined;

[0159] The brake caliper is braked based on the brake hydraulic control.

[0160] Optionally, the device further includes a state determination module, used for:

[0161] Obtain the motor speed of the drive motor;

[0162] The condition of the brake disc is determined based on the motor speed to determine whether it meets the test conditions.

[0163] Optionally, the state determination module is further configured to:

[0164] If the motor speed is less than the upper limit of the speed under the test conditions, it is determined that the state of the brake disc meets the test conditions.

[0165] If the motor speed is greater than the upper limit of the speed under the test conditions, it is determined that the state of the brake disc does not meet the test conditions.

[0166] Optionally, the device further includes a hydraulic adjustment module for:

[0167] When the motor speed is greater than the upper limit of the speed under the test conditions, the braking hydraulic pressure of the hydraulic brake is increased based on the boost step size.

[0168] Optionally, the device further includes an environmental control module for:

[0169] During the test, real-time environmental parameters within the environmental chamber were acquired.

[0170] Based on the real-time environmental parameters, the environment chamber is controlled to adjust the test environment to keep the test environment stable.

[0171] Optionally, the apparatus further includes a result determination module, used for:

[0172] Based on the braking sound under different test conditions and test environments, the test results of the brake pad under test are determined.

[0173] Optionally, the result determination module is further configured to:

[0174] Based on the test condition parameters under different test conditions, the environmental parameters of the test environment, and the sound pressure parameters of the braking sound, a braking sound pressure curve of the brake pad to be tested is generated. The braking sound pressure curve is used to characterize the correspondence between the test conditions, the test environment, and the sound pressure parameters. The test result of the brake pad to be tested is determined based on the braking sound pressure curve.

[0175] The result determination module is also used for:

[0176] The test condition parameters under different test conditions, the environmental parameters of the test environment, and the sound pressure parameters of the braking sound are spliced ​​together to obtain the brake pad data of the brake pad to be tested; the brake pad data is input into the brake pad evaluation model to obtain the brake pad test result output by the brake sound evaluation model, and the brake pad evaluation model is trained based on the sample brake pad data of the sample brake pad and the sample brake pad test result of the sample brake pad.

[0177] In this embodiment, the control console can adjust the ambient temperature and humidity of the environment where the brake pads are located through the environmental chamber, so as to avoid the influence of changes in ambient temperature and humidity on the acquisition results. The control console can also simulate the working conditions of a vehicle starting on a slope by controlling the brake calipers of the drive motor and hydraulic brake, and collect the braking sound generated by the friction between the brake pads and the brake disc, which helps to reduce the result deviation caused by human error. In summary, the technical solution provided by this embodiment can improve the accuracy of the brake sound acquisition results.

[0178] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware, or by a program guiding the relevant hardware to be implemented. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0179] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for collecting braking sound, characterized in that, The method is used in a braking sound acquisition system, which includes: a suspension, a hydraulic brake, a drive motor, a microphone, an environmental chamber, and a control console. The hydraulic brake is mounted on the suspension, and the suspension and the hydraulic brake are mounted in the environmental chamber. The torque output end of the drive motor is connected to the brake disc of the hydraulic brake via a connecting shaft. The brake caliper of the hydraulic brake is equipped with a brake pad to be tested. The control console is connected to the environmental chamber, the hydraulic brake, the drive motor, and the microphone. The method is executed by the console in the brake sound acquisition system, and the method includes: The environmental chamber is controlled to set up the test environment, which includes ambient humidity and ambient temperature. Under the test environment, the parking braking torque is determined based on the test conditions. The parking braking torque is the minimum braking torque required for parking on a slope. The test conditions are downhill start conditions controlled by the brake pedal. The parking braking torque T1 = mg. sin(a) R / 2, where m is the vehicle mass, g is the gravity coefficient, a is the slope angle, and R is the vehicle rolling radius; The parking braking torque is determined to be the motor torque of the drive motor under the test conditions; The drive motor is controlled to output torque based on the motor torque. The output motor torque is applied to the brake disc, causing the brake disc to have a rotational tendency when the vehicle rolls downhill. Based on the parking braking torque and the brake parameters of the hydraulic brake, the braking hydraulic pressure P is determined; the braking torque generated by the hydraulic brake under the braking hydraulic pressure P is equal to the parking braking torque. The pressure of the brake fluid is controlled to exceed the brake fluid pressure P, so that the brake disc can remain stationary when the drive motor outputs motor torque; after the brake fluid pressure is continuously increased for a period of time, the pressure of the brake fluid is controlled to slowly decrease until the state of the brake disc meets the test conditions; When the brake disc is in a condition that meets the test conditions, the braking sound collected by the microphone is obtained. The braking sound is generated by the friction between the brake pad under test and the brake disc. The condition that the brake disc is in a condition that meets the test conditions means that the brake disc is in a critical state that is about to disengage from the brake caliper. In the critical state, the friction type between the brake pad and the brake disc alternates between dynamic friction and static friction, and the brake disc vibrates. Specifically, if the motor speed of the drive motor is less than the upper limit of the speed under the test conditions, the brake disc state is determined to meet the test conditions.

2. The method according to claim 1, characterized in that, Before acquiring the braking sound collected by the microphone when the brake disc is in the condition that meets the test conditions, the method includes: Obtain the motor speed of the drive motor; The condition of the brake disc is determined based on the motor speed to determine whether it meets the test conditions.

3. The method according to claim 2, characterized in that, The step of determining whether the state of the brake disc meets the test conditions based on the motor speed includes: If the motor speed is greater than the upper limit of the speed under the test conditions, it is determined that the state of the brake disc does not meet the test conditions.

4. The method according to claim 3, characterized in that, The method further includes: When the motor speed is greater than the upper limit of the speed under the test conditions, the braking hydraulic pressure of the hydraulic brake is increased based on the boost step size.

5. The method according to claim 1, characterized in that, The method further includes: During the test, real-time environmental parameters within the environmental chamber were acquired. Based on the real-time environmental parameters, the environment chamber is controlled to adjust the test environment to keep the test environment stable.

6. The method according to claim 1, characterized in that, The method further includes: Based on the braking sound under different test conditions and test environments, the test results of the brake pad under test are determined.

7. The method according to claim 6, characterized in that, The method of determining the brake pad test result based on the braking sound under different test conditions and environments includes: Based on the test condition parameters under different test conditions, the environmental parameters of the test environment, and the sound pressure parameters of the braking sound, a braking sound pressure curve of the brake pad to be tested is generated. The braking sound pressure curve is used to characterize the correspondence between the test conditions, the test environment, and the sound pressure parameters. The test result of the brake pad to be tested is determined based on the braking sound pressure curve. or, The test condition parameters under different test conditions, the environmental parameters of the test environment, and the sound pressure parameters of the braking sound are spliced ​​together to obtain the brake pad data of the brake pad to be tested; the brake pad data is input into the brake pad evaluation model to obtain the brake pad test results output by the brake pad evaluation model, which is trained based on the sample brake pad data and the sample brake pad test results of the sample brake pad.

8. A braking sound acquisition device, characterized in that, The device includes: An environmental control module is used to control the setting of the test environment in the environmental chamber, the test environment including ambient humidity and ambient temperature; The operating condition control module is used to determine the parking braking torque based on the test operating conditions under the test environment. The parking braking torque is the minimum braking torque required for parking on a slope. The test operating conditions are downhill start conditions controlled by the brake pedal. The parking braking torque T1 = mg. sin(a) R / 2, where m is the vehicle mass, g is the gravity coefficient, a is the slope angle, and R is the vehicle's rolling radius; the parking braking torque is determined as the motor torque of the drive motor under the test conditions; based on the motor torque, the drive motor is controlled to output torque, which is then applied to the brake disc, causing the brake disc to have a rotational tendency when the vehicle rolls downhill; based on the parking braking torque and the brake parameters of the hydraulic brake, the brake hydraulic pressure P is determined; the braking torque generated by the hydraulic brake under the brake hydraulic pressure P is equal to the parking braking torque; the brake fluid pressure is controlled to exceed the brake hydraulic pressure P, so that the brake disc can remain stationary when the drive motor outputs motor torque; after the brake fluid pressure is continuously increased for a period of time, the brake fluid pressure is controlled to slowly decrease until the state of the brake disc meets the test conditions; The acquisition module is used to acquire the braking sound collected by the microphone when the brake disc is in a state that meets the test conditions. The braking sound is generated by the friction between the brake pad under test at the brake caliper and the brake disc. The state of the brake disc meeting the test conditions means that the brake disc is in a critical state that is about to disengage from the brake caliper and rotate. In the critical state, the friction type between the brake pad and the brake disc alternates between dynamic friction and static friction, and the brake disc vibrates. Specifically, if the motor speed of the drive motor is less than the upper limit of the speed under the test conditions, the brake disc state is determined to meet the test conditions.

9. A braking sound acquisition system, characterized in that, The braking sound acquisition system includes: The system includes a suspension, a hydraulic brake, a drive motor, a microphone, an environmental chamber, and a control console. The hydraulic brake is mounted on the suspension, and the suspension and the hydraulic brake are located in the environmental chamber. The torque output end of the drive motor is connected to the brake disc of the hydraulic brake via a connecting shaft. The brake caliper of the hydraulic brake is equipped with a brake pad to be tested. The control console is connected to the environmental chamber, the hydraulic brake, the drive motor, and the microphone. The console is used to control the environmental chamber to set the test environment, which includes ambient humidity and ambient temperature; The control console is also used to determine the parking braking torque based on the test conditions under the test environment, wherein the parking braking torque is the minimum braking torque required for parking on a slope; the test conditions are downhill start conditions controlled by the brake pedal; and the parking braking torque T1 = mg. sin(a) R / 2, where m is the vehicle mass, g is the gravity coefficient, a is the slope angle, and R is the vehicle's rolling radius; the parking braking torque is determined as the motor torque of the drive motor under the test conditions; based on the motor torque, the drive motor is controlled to output torque, which is then applied to the brake disc, causing the brake disc to have a rotational tendency when the vehicle rolls downhill; based on the parking braking torque and the brake parameters of the hydraulic brake, the brake hydraulic pressure P is determined; the braking torque generated by the hydraulic brake under the brake hydraulic pressure P is equal to the parking braking torque; the brake fluid pressure is controlled to exceed the brake hydraulic pressure P, so that the brake disc can remain stationary when the drive motor outputs motor torque; after the brake fluid pressure is continuously increased for a period of time, the brake fluid pressure is controlled to slowly decrease until the state of the brake disc meets the test conditions; The control console is also used to acquire the braking sound collected by the microphone when the brake disc is in the state of the test condition. The braking sound is generated by the friction between the brake pad under test and the brake disc. The state of the brake disc being in the test condition means that the brake disc is in a critical state about to disengage from the brake caliper. In the critical state, the friction type between the brake pad and the brake disc alternates between dynamic friction and static friction, and the brake disc vibrates. Specifically, if the motor speed of the drive motor is less than the upper limit of the speed under the test conditions, the brake disc state is determined to meet the test conditions.

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