A test method and system for checking brake efficiency by using a k & c test bench

Abstract

The application relates to a test method and system for checking braking efficiency by using a K&C test bench, and relates to the technical field of vehicle braking, which comprises the following steps: placing a test vehicle on an angle platform, the angle platform being provided with a friction disc and an angle sensor; after fixing the vehicle body and the steering wheel and applying maximum braking force to the brake pedal, the angle platform is controlled to move backward relative to the vehicle body and gradually increase the longitudinal force of the angle platform on the wheels; the friction force applied to the wheels by the angle platform is obtained by processing the friction coefficient of the friction disc and the longitudinal force; the rotation angle of the wheel center is collected by a plurality of data collection sensors; and an analysis report of the vehicle braking efficiency check is obtained by processing the friction force, the rotation angle, the displacement amount of the angle platform and the output braking force of the test vehicle. The application can control the movement of the angle platform relative to the wheels and the longitudinal force applied to the wheels during the movement, collect relevant parameters for analysis, and determine whether the vehicle braking efficiency meets the standard and the specific reason for the braking deficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle braking, in particular to a test method and system for checking braking efficiency by using a K&C test bench. BACKGROUND

[0002] K&C is the abbreviation of Kinematics&Compliance, which refers to the rigid kinematics and elastic kinematics of automobile suspension. The hardware of the K&C test bench mainly consists of four parts: a test bench base and a vehicle body fixing module, a loading module, a measurement and control system, and a user interactive interface. The base provides stiffness support and also facilitates platform module adjustment and alignment to adapt to vehicle tests of different wheelbases and track widths, including four corner platforms. The vehicle body fixing device can help fix the vehicle body during testing, and has various clamping fixing mechanisms such as hydraulic, electromagnetic and mechanical. The loading module mainly applies displacement and force to the wheels, including a loading platform and a power source. The measurement and control system mainly controls the movement of the wheels and acquires data, which is stored or output to the upper computer after corresponding conversion processing, including wheel center displacement sensors arranged on the outer side of the corner platforms for measuring the toe angle and camber angle of the wheels. The wheel center displacement sensor includes a mechanical arm, a connecting disc connected to the mechanical arm, and a plurality of sensors arranged at the junction of the mechanical arm and the connecting disc, which can measure the change values of the toe angle and camber angle of the tires during K&C testing. The user interactive interface is mainly used to provide users with control buttons and control screens of various switches to control the test operation, and also to observe the running status of the main equipment.

[0003] The automobile braking system refers to a series of special devices that apply a certain force to some parts of the automobile (mainly the wheels) to forcibly brake them to a certain extent. The functions of the braking system are: to make the moving automobile decelerate or even stop according to the requirements of the driver; to make the stopped automobile stable on various road conditions (including on slopes); and to keep the speed of the downhill running automobile stable. The automobile braking system mainly includes disc brakes, also known as disc brakes. The disc brakes on the automobile are composed of a brake oil pump, a brake disc connected to the wheels, and brake calipers on the disc. When braking, high-pressure brake oil pushes the piston in the brake caliper to press the brake shoes against the brake disc, thereby producing a braking effect.

[0004] In the early stage of vehicle development, especially the first batch of test vehicles, it is easy to cause the braking performance of the vehicle to be not high due to various reasons (sample quality, manufacturing error, calibration, etc.). After the test vehicle is trial-produced and driven on the road, the vehicle can be stopped, but it is difficult to judge whether the braking performance reaches the designed value. For example, the test vehicle can be stopped on the road, but the braking effect of the braking system is not good, and the braking distance is also longer. When the test vehicle is tested on some test benches, according to the test process, the test vehicle needs to be braked so that the wheels cannot rotate. The vehicle that can be stopped on the road may slip on some test benches because the force applied by the test bench is relatively large, and the wheels will slip because they cannot be stopped, thereby causing the test to be unable to proceed normally.

[0005] There are three kinds of situations of insufficient braking as follows:

[0006] 1) If there is no slip between the wheel and the ground, and slip occurs between the brake caliper and the brake disc, it indicates that the brake caliper braking force is insufficient and the brake disc cannot be locked.

[0007] 2) If slip occurs between the wheel and the ground, and no slip occurs between the brake caliper and the brake disc, that is, the friction between the ground and the tire is insufficient.

[0008] 3) If slip occurs between the wheel and the ground, and slip occurs between the brake caliper and the brake disc, it indicates that the brake caliper braking force is insufficient and the friction between the ground and the tire is insufficient. SUMMARY

[0009] In view of the defects in the prior art, the purpose of the present application is to provide a test method and system for checking braking efficiency by using a K&C test bench, which can control the relative movement of the angle platform to the wheel and the longitudinal force applied to the wheel during movement, collect relevant parameters for analysis, and determine whether the vehicle braking efficiency meets the standard and the specific reason for insufficient braking.

[0010] To achieve the above purpose, the technical scheme adopted is:

[0011] A test method for checking braking efficiency by using a K&C test bench, comprising:

[0012] Placing four wheels of a test vehicle on four angle platforms, respectively, and setting friction discs on the upper surfaces of the four angle platforms in contact with the wheels, and setting an angle sensor on the wheel center;

[0013] Fixing the vehicle body and the steering wheel, and applying the maximum braking force to the brake pedal, then controlling the four angle platforms to move backward relative to the vehicle body, and gradually increasing the longitudinal force of the four angle platforms on the four wheels during movement;

[0014] According to the friction coefficient of the friction disc and the longitudinal force, a friction force applied to the wheel by the angle platform is processed, and a rotation angle of a wheel center of the wheel is collected by the plurality of angle sensors;

[0015] According to the friction force, the rotation angle, the displacement of the angle platform, and a braking force output by the test sample vehicle, an analysis report of a vehicle braking performance check is processed.

[0016] In some embodiments, the maximum braking force is 500 N.

[0017] In some embodiments, the method comprises performing the test by using friction discs with different friction coefficients to obtain the analysis report.

[0018] The friction coefficient of the friction disc ranges from 0.1 to 1.3.

[0019] In some embodiments, the friction coefficients of the friction discs on the four angle platforms are the same.

[0020] In some embodiments, the diameter of the friction disc is not less than 50 cm.

[0021] In some embodiments, the longitudinal forces applied to the two angle platforms corresponding to the two front wheels are the same, and the longitudinal forces applied to the two angle platforms corresponding to the two rear wheels are the same.

[0022] In some embodiments, the analysis report of the vehicle braking performance check is processed according to the friction force, the rotation angle, the displacement of the angle platform, and the braking force output by the test sample vehicle, and specifically comprises the following steps:

[0023] A first curve is generated with the friction force as the horizontal coordinate and the rotation angle as the vertical coordinate;

[0024] A second curve is generated with the friction force as the horizontal coordinate and the displacement of the angle platform as the vertical coordinate;

[0025] The mutation of the first curve and the second curve is determined:

[0026] If neither the first curve nor the second curve has a mutation, the analysis report is that the braking force of the braking system meets the standard;

[0027] If the first curve has a mutation and the second curve does not have a mutation, the analysis report is that the braking force of the braking system does not meet the standard;

[0028] If the first curve does not have a mutation and the second curve has a mutation, the analysis report is that the braking force of the braking system meets the standard and the friction force between the tire and the ground is insufficient;

[0029] If both the first curve and the second curve have a mutation, the analysis report is that the braking force of the braking system does not meet the standard and the friction force between the tire and the ground is insufficient.

[0030] In some embodiments, during the test, the braking force output by the braking system is the same as the friction force before the first curve and the second curve have a mutation;

[0031] During the test, if any one of the two curves has a mutation, the corresponding braking force and angular displacement at the mutation point are calculated, the braking force is taken as the maximum braking force and the maximum braking distance of the braking system, and the analysis report includes the maximum braking force and the maximum braking distance.

[0032] In some embodiments, the braking force output by the braking system on the two front wheels and the braking force output by the braking system on the two rear wheels are calculated using the following formula:

[0033]

[0034] Wherein,

[0035] is used to represent the braking force output by the braking system on the two front wheels;

[0036] is used to represent the braking force output by the braking system on the two rear wheels;

[0037] G is used to represent the gravity of the whole vehicle;

[0038] L is used to represent the wheelbase of the vehicle;

[0039] is used to represent the horizontal distance from the center of mass of the vehicle to the center line of the front axle of the vehicle;

[0040] is used to represent the horizontal distance from the center of mass of the vehicle to the center line of the rear axle of the vehicle;

[0041] is used to represent the friction coefficient of the friction disc;

[0042] is used to represent the height of the center of mass of the vehicle.

[0043] A test system for checking the braking efficiency of a vehicle using a K&C test bench, the system comprising a K&C test bench; the system further comprises:

[0044] A mechanical arm for placing the four wheels of the test vehicle on the four angle platforms respectively after the upper surfaces of the four angle platforms in contact with the wheels are respectively provided with friction discs, and for setting angle sensors on the wheel centers of the wheels;

[0045] A control component is configured to fix the vehicle body and the steering wheel, and to apply a maximum braking force to the brake pedal, and to control the four corner platforms to move rearward relative to the vehicle body and gradually increase the longitudinal force of the four corner platforms on the four wheels during the movement;

[0046] A processing component is configured to process the friction force of the corner platforms on the wheels according to the friction coefficient of the friction disc and the longitudinal force, to collect the rotation angle of the wheel center of the wheels by the plurality of angle sensors, and to process the analysis report of the vehicle braking performance verification according to the friction force, the rotation angle, the displacement amount of the corner platforms, and the braking force output by the test vehicle.

[0047] The technical scheme provided by the present application has the beneficial effects that the movement of the corner platforms relative to the wheels and the longitudinal force applied to the wheels during the movement of the K&C test bench are controlled, and the related parameters are collected and analyzed to determine whether the vehicle braking performance meets the standard and the specific reason for the braking deficiency.

[0048] The friction disc is arranged at the position where the corner platform contacts the wheel, and the friction disc with different friction coefficients can be replaced during the test, so that the braking performance of the vehicle running on the road surface with different friction coefficients can be verified.

[0049] The first curve is generated by taking the friction force as the horizontal coordinate and the rotation angle as the vertical coordinate, and the second curve is generated by taking the friction force as the horizontal coordinate and the displacement amount of the corner platforms as the vertical coordinate, and the specific reason for the braking deficiency of the vehicle is analyzed according to the mutation of the first curve and the second curve, so that the braking deficiency of the test vehicle can be quickly detected and improved later.

[0050] The braking force corresponding to the positions where the first curve and the second curve start to mutate is taken as the maximum braking force of the current braking system of the vehicle, which can be compared with the ideal value to determine whether the braking force meets the ideal design state, and the vehicle can be improved later. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 The flowchart of the test method for verifying the braking performance by using the K&C test bench in the embodiments of the present application.

[0052] Figure 2 The schematic diagram of the force condition during the braking process for verifying the braking performance by using the K&C test bench in the embodiments of the present application.

[0053] Figure 3 The schematic diagram of the first curve in the embodiments of the present application.

[0054] Figure 4 The schematic diagram of the first curve in the embodiments of the present application.

[0055] Figure 5 Fig. 2 is a schematic diagram of a second curve in an embodiment of the present application.

[0056] Figure 6 Fig. 3 is a schematic diagram of a second curve in an embodiment of the present application.

[0057] Figure 7 Fig. 4 is a schematic diagram of a function module of a test system for checking brake efficiency using a K&C test bench in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0059] A test sample vehicle refers to various sample vehicles produced by an automobile manufacturer during the development of new products, mainly used for various evaluations and performance tests of new products. According to the design data verification test vehicle production in the new vehicle development process, the design problem points are analyzed and corrected in advance. The vehicle that can be evaluated is produced in advance to meet the technical requirements of sufficient verification and evaluation. It can find the irrationality of part design and structure design, and feedback to the design and development department to shorten the development period and development cost. In the development and production stage of the test sample vehicle, according to the design data, the sample parts and sample vehicles are produced in the shortest period of time by using trial production process. The formability of the body stamping parts and the unreasonable factors of the design structure can be checked before the formal mold is put into production. It can control the change of design node in the early stage of the body design stage, thereby saving the development cycle and reducing the development cost.

[0060] Brake efficiency refers to the ratio of the deceleration generated by the vehicle during braking to the weight of the vehicle during braking, which is an important indicator of measuring the braking performance of the automobile. The indicators for evaluating brake efficiency mainly include braking distance, braking time and braking stability, etc. The braking distance refers to the distance required from the start of braking to the complete stop of the vehicle, which is usually measured based on the vehicle speed. The braking time refers to the time required from the start of braking to the complete stop of the vehicle, which is also one of the important indicators for measuring brake efficiency. The braking stability refers to the stability performance of the vehicle during braking, including the attitude of the vehicle during braking, the stability of the suspension and the grip of the tire, etc. In summary, the indicators for evaluating the brake efficiency of the automobile are multifaceted, and various factors need to be considered comprehensively to make an accurate conclusion.

[0061] The embodiment of the present application provides a test method for checking braking efficiency by using a K&C test bench, which comprises the following steps: placing four wheels of a test vehicle on four corner platforms respectively, arranging a friction disc on the upper surface of each corner platform in contact with the wheel, and arranging an angle sensor on the wheel hub.

[0062] In the embodiment, the movement of the corner platform relative to the wheel and the longitudinal force applied to the wheel during the movement can be controlled, and relevant parameters can be collected and analyzed to determine whether the braking efficiency of the vehicle meets the standard and the specific reason for the braking deficiency.

[0063] The corner platform is provided with a friction disc at the position in contact with the wheel, and the friction disc with different friction coefficients can be replaced during the test, so that the braking efficiency of the vehicle running on the road surface with different friction coefficients can be checked.

[0064] In one specific embodiment, as shown in Figure 1 The test method for checking braking efficiency by using the K&C test bench specifically comprises the following steps:

[0065] Step S1, placing four wheels of a test vehicle on four corner platforms respectively, arranging a friction disc on the upper surface of each corner platform in contact with the wheel, and arranging an angle sensor on the wheel hub.

[0066] Step S2, fixing the vehicle body and steering wheel, applying the maximum braking force to the brake pedal, controlling the four corner platforms to move backward relative to the vehicle body, and gradually increasing the longitudinal force of the four corner platforms on the four wheels during the movement.

[0067] Step S3, according to the friction coefficient of the friction disc and the longitudinal force, the friction force of the corner platform applied to the wheel is obtained, and the rotation angle of the wheel hub is collected by the angle sensor.

[0068] Step S4, according to the friction force, rotation angle, corner platform displacement, and braking force output by the test vehicle, an analysis report of the vehicle braking efficiency check is obtained.

[0069] During the test, if the wheel and the ground are determined to have no slip according to the friction force and the rotation angle, and the brake caliper and the brake disc slip, it indicates that the brake caliper is insufficient in braking force and fails to lock the brake disc. If the wheel and the ground slip, and the brake caliper and the brake disc do not slip, it indicates that the friction force between the ground and the tire is insufficient. If the wheel and the ground slip, and the brake caliper and the brake disc slip, it indicates that both the brake caliper is insufficient in braking force and the friction force between the ground and the tire is insufficient.

[0070] In the embodiment, since the tire itself has elasticity, during the movement of the angle platform to the rear relative to the tire, the friction force between the friction disc and the tire increases with the increase of the longitudinal force applied by the angle platform, and the braking force output by the braking system also increases with the increase of the friction force. At the same time, the elastic deformation of the tire caused by the friction force further causes the rotation angle of the wheel center to gradually change. If the friction force and the displacement of the angle platform increase to a certain extent, if the braking force of the braking system is insufficient, the brake caliper and the brake disc may slip, and correspondingly, the rotation angle may suddenly change. If the friction force between the tire and the ground is insufficient, the wheel and the ground may slip, and the displacement of the angle platform may suddenly change. If both the braking force of the braking system and the friction force between the tire and the ground are insufficient, both the rotation angle and the displacement of the angle platform may suddenly change. The braking force corresponding to the sudden change point is the maximum braking force of the current braking system, and the displacement of the angle platform corresponding to the sudden change point is the maximum braking distance of the current braking system.

[0071] The application can control the movement of the angle platform relative to the wheel and the longitudinal force applied to the wheel, collect relevant parameters for analysis, to determine whether the braking efficiency of the vehicle meets the standard and the specific reason for the insufficient braking.

[0072] Further, the friction disc is arranged at the contact position between the angle platform and the wheel, and friction discs with different friction coefficients can be replaced during the test, so as to check the braking efficiency of the vehicle running on the road surface with different friction coefficients.

[0073] The braking system of the test vehicle is intended to use the front and rear brake types of the benchmark vehicle, and adopts hydraulic assistance. The front brake is a ventilated disc brake, and the rear brake is a leading and following shoe drum brake. The front and rear wheel cylinders are intended to use the size of the benchmark vehicle. The brake pedal is a hanging pedal with a vacuum booster. Since the intersection point of the kingpin extension line and the ground is inside the wheel contact point, in order to improve the braking stability, the brake pipeline needs to adopt a type II double-circuit front and rear axle separation structure form, and a load sensing proportional valve is also assembled. The parking brake system is a mechanical manual type, which brakes the rear wheel and adopts a long-distance ratchet cable control mechanism.

[0074] In one specific embodiment, as Figure 2As shown, using the K&C test bench to verify vehicle braking performance can identify problems with insufficient braking performance through testing methods. The test method includes clamping the test vehicle onto the K&C test bench, applying a maximum braking force of 500N to the brake pedal, fixing the steering wheel, and mounting a 50cm diameter friction disc on the surface disc of the angle platform acting on the tires. The friction coefficient of the friction disc can be replaced. Assuming the car brakes at a deceleration of 'a', applying a braking force of 'a' to the front axle... A vertically upward force is applied to the rear axle. The force that is vertically upward, because , Then the force situation during its braking process is as follows: Figure 2 As shown, by taking moments about the contact points of the front and rear wheels respectively, we can obtain:

[0075] (1)

[0076] In the above formula, , These are the normal reaction forces exerted by the friction disk on the front and rear wheels, respectively, in N. The total vehicle weight is expressed in kg. For the weight of the whole vehicle, The unit is N. This is the horizontal distance from the vehicle's center of gravity to the center line of the front axle, expressed in mm. This is the horizontal distance from the vehicle's center of gravity to the rear axle centerline, expressed in mm. The height of the vehicle's center of gravity is measured in mm. This refers to the wheelbase, in mm.

[0077] During braking, the ideal braking state is that both the front and rear wheels lock up simultaneously. This occurs when the coefficient of friction is... On a road surface, the condition for both the front and rear wheels to lock up simultaneously is that the sum of the braking forces of the front and rear wheels equals the adhesion force (i.e., friction force), and the braking forces of the front and rear wheels are each equal to their respective adhesion forces.

[0078] (2)

[0079] in, , These represent the frictional forces exerted by the friction disc on the front and rear wheels, respectively.

[0080] In addition, when both wheels lock up, the vehicle's braking deceleration is: Substituting into formula (1) above, we get:

[0081] (3)

[0082] Substituting formula (3) into formula (2), we get:

[0083] (4)

[0084] Eliminate variables The adhesion coefficient can be obtained as follows: The relationship between the braking forces of the front and rear brakes when both wheels lock up simultaneously on a road surface:

[0085] (5)

[0086] Before the wheels lock up, the braking force exerted by the ground on the wheels is equal to the braking force of the brakes, that is... , .

[0087] When processing the analysis report, the braking force of the front wheel can be obtained by processing the relevant data of the front wheel, and then the braking force of the rear wheel can be derived according to formula (5) to improve the calculation efficiency.

[0088] In a preferred embodiment, the maximum braking force is 500 N.

[0089] In this embodiment, 500N is the theoretical braking force on the brake pedal during emergency braking.

[0090] In a preferred embodiment, the method includes conducting the tests using friction disks with different coefficients of friction to obtain the analysis report.

[0091] The friction coefficient of the friction disk ranges from 0.1 to 1.3.

[0092] In a preferred embodiment, the friction discs on the four corner platforms have the same coefficient of friction.

[0093] In a preferred embodiment, the diameter of the friction disk is not less than 50 cm.

[0094] In this embodiment, the diameter of the friction disk must be no less than the maximum width of the contact surface between the test vehicle and the friction disk.

[0095] In a preferred embodiment, the longitudinal forces applied to the two corner platforms corresponding to the two front wheels are the same, and the longitudinal forces applied to the two corner platforms corresponding to the two rear wheels are the same.

[0096] In a preferred embodiment, the step of processing the friction force, rotation angle, angular platform displacement, and braking force output by the test vehicle to obtain the vehicle braking performance verification analysis report specifically includes the following steps:

[0097] A first curve is generated with the frictional force as the abscissa and the rotation angle as the ordinate. A second curve is generated with the frictional force as the abscissa and the angular platform displacement as the ordinate.

[0098] Determine the abrupt changes in the first and second curves:

[0099] If neither the first curve nor the second curve shows any abrupt change, then the analysis report indicates that the braking force of the braking system meets the standard.

[0100] If the first curve shows a sudden change and the second curve does not, the analysis report indicates that the braking force of the braking system is substandard.

[0101] If the first curve shows no abrupt change but the second curve shows abrupt change, then the analysis report indicates that the braking force of the braking system meets the standard and the friction between the tire and the ground is insufficient.

[0102] If both the first and second curves show abrupt changes, the analysis report indicates that the braking force of the braking system is insufficient and the friction between the tires and the ground is inadequate.

[0103] Furthermore, during the test, before the abrupt changes in the first and second curves, the braking force output by the braking system was the same as the frictional force.

[0104] During the test, if either of the two curves shows a sudden change, the braking force and angular platform displacement corresponding to the sudden change point are calculated. The braking force is used as the maximum braking force and maximum braking distance of the braking system, and the analysis report includes the maximum braking force and maximum braking distance.

[0105] Furthermore, the braking force output by the braking system on the two front wheels and the braking force output by the braking system on the two rear wheels are calculated using the following formulas:

[0106] (6)

[0107] in, Used to indicate the braking force output by the braking system on the two front wheels. This indicates the braking force output by the braking system on the two rear wheels. G represents the total weight of the vehicle; L represents the wheelbase. Used to indicate the horizontal distance from the center of gravity of a car to the center line of the front axle. Used to indicate the horizontal distance from the center of gravity of a car to the center line of the rear axle. The coefficient of friction is used to represent the friction coefficient of a friction disk. Used to indicate the height of a car's center of gravity.

[0108] In one specific embodiment, during the test, the lateral forces and moments about the Z-axis of the left and right corner platforms remained zero, while the vertical positions and roll angles of the left and right corner platforms remained unchanged. A rearward longitudinal force was applied to the front wheel corner platform along the X-axis. The rear wheel angle platform applies a rearward longitudinal force along the X-axis direction. With a brake pedal applied at 500N, if a rearward longitudinal force is applied to the front wheel angle platform along the X-axis... The rear wheel angle platform applies a rearward longitudinal force along the X-axis direction. If the wheels do not slip or rotate, it verifies that the braking performance of the manufactured vehicle meets the design value.

[0109] The longitudinal force limit is 0.5G (if the wheel slips / rotates, the maximum longitudinal force when the wheel does not slip / rotate is taken as the limit).

[0110] If the wheel slips / rotates, the maximum longitudinal force when the wheel does not slip / rotate is taken as the limit.

[0111] At the same time, there is also a design value for the force applied to the brake pedal. We can apply a rearward longitudinal force along the X-axis through the front wheel platform under the condition of applying the design value. The rear wheel platform applies a rearward longitudinal force along the X-axis. This is used to verify whether the wheels slip or rotate, and then to determine whether the design requirements are met.

[0112] The output and monitoring data include the platform displacement X, the longitudinal force Fx applied by the platform, and the rotation angle A of the wheel center.

[0113] If the first scenario in the aforementioned background technology occurs due to insufficient braking: the wheel does not slip with the ground, but the brake caliper slips between itself and the brake disc. That is, the brake caliper's braking force is insufficient and it fails to lock the brake disc. This is determined by monitoring the wheel's rotation angle A and the applied longitudinal force Fx. Figure 3 The curve represents normal braking, with the horizontal axis representing the longitudinal force Fx applied by the platform and the vertical axis representing the rotation angle A. If the first scenario occurs, the curve will look like... Figure 4 The rotation angle of the wheel's center will undergo a sudden change.

[0114] If the second type of insufficient braking occurs: the wheel slips off the ground, but the brake caliper and brake disc do not slip, meaning there is insufficient friction between the ground and the tire, this is determined by monitoring the platform's displacement X and the applied longitudinal force Fx. Figure 5 The curve represents normal braking, with the horizontal axis representing the longitudinal force Fx applied by the platform and the vertical axis representing the platform's displacement X. If the first scenario occurs, the curve will look like... Figure 6 The platform's displacement X will undergo a sudden change.

[0115] If the third type of insufficient braking occurs—where the wheel slips off the ground and the brake caliper rotates between the brake disc and the brake caliper—it is a superposition of the two sudden changes mentioned above.

[0116] In summary, the technical solution of the present invention can detect braking performance problems in the early stages of research and development, and can verify whether the design and manufacturing of the braking system have achieved the design values.

[0117] like Figure 7 As shown, this invention also provides an embodiment of a test system for verifying braking performance using a K&C test bench, including a K&C test bench, a robotic arm, a control component, and a processing component. The robotic arm is used to place the four wheels of the test vehicle on the four corner platforms after setting friction discs on the upper surfaces of the four corner platforms that contact the wheels. It is also used to set angle sensors at the wheel centers. The control component is used to fix the vehicle body and steering wheel, and after applying maximum braking force to the brake pedal, it controls the four corner platforms to move backward relative to the vehicle body, gradually increasing the longitudinal force exerted by the four corner platforms on the four wheels during the movement. The processing component is used to process the friction force applied to the wheels by the corner platforms based on the friction coefficient of the friction discs and the longitudinal force, collect the rotation angle of the wheel centers through the multiple angle sensors, and process the friction force, rotation angle, corner platform displacement, and braking force output by the test vehicle to obtain an analysis report on vehicle braking performance verification.

[0118] In this embodiment, by controlling the movement of the control angle platform relative to the wheel and the longitudinal force applied to the wheel during movement, relevant parameters can be collected and analyzed to determine whether the vehicle's braking performance meets the standard and the specific reasons for insufficient braking.

[0119] Friction discs are installed at the contact points between the corner platform and the wheels. During testing, friction discs with different coefficients of friction can be replaced to verify the braking performance of the vehicle on road surfaces with different coefficients of friction.

[0120] A first curve is generated with the friction force as the abscissa and the rotation angle as the ordinate, and a second curve is generated with the friction force as the abscissa and the angular platform displacement as the ordinate. Based on the abrupt changes of the first and second curves, the specific reasons for insufficient braking of the vehicle can be analyzed. This allows for the rapid detection of insufficient braking of the test vehicle, facilitating its subsequent improvement.

[0121] The braking force corresponding to the point where the first and second curves begin to change abruptly is taken as the maximum braking force of the vehicle's current braking system. This force can be compared with the set ideal value to determine whether the braking force has reached the ideal design state, which facilitates future improvements.

[0122] The test system in this embodiment is applicable to the above-described test methods.

[0123] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A test method for verifying braking performance using a K&C test bench, characterized in that, The method includes: The four wheels of the test vehicle were placed on the four corner platforms. Friction discs were set on the upper surfaces of the four corner platforms that contacted the wheels, and angle sensors were set at the wheel centers. After fixing the vehicle body and steering wheel and applying maximum braking force to the brake pedal, control the four corner platforms to move backward relative to the vehicle body, and gradually increase the longitudinal force of the four corner platforms on the four wheels during the movement. The frictional force applied to the wheel by the angle platform is obtained based on the friction coefficient of the friction disk and the longitudinal force processing, and the rotation angle of the wheel center is collected by multiple angle sensors. Based on the friction force, rotation angle, angular platform displacement, and braking force output by the test vehicle, an analysis report on vehicle braking performance verification is obtained. This process of obtaining the analysis report on vehicle braking performance verification based on the friction force, rotation angle, angular platform displacement, and braking force output by the test vehicle specifically includes the following steps: A first curve is generated with the frictional force as the abscissa and the rotation angle as the ordinate; A second curve is generated with the frictional force as the abscissa and the angular platform displacement as the ordinate; Determine the abrupt changes in the first and second curves: If neither the first curve nor the second curve shows any abrupt change, then the analysis report indicates that the braking force of the braking system meets the standard. If the first curve shows a sudden change and the second curve does not, then the analysis report indicates that the braking force of the braking system is substandard. If the first curve has no sudden change but the second curve has a sudden change, then the analysis report indicates that the braking force of the braking system meets the standard and the friction between the tire and the ground is insufficient. If both the first and second curves show abrupt changes, the analysis report indicates that the braking force of the braking system is insufficient and the friction between the tires and the ground is inadequate.

2. The test method for verifying braking performance using a K&C test bench as described in claim 1, characterized in that, The maximum braking force is 500N.

3. The test method for verifying braking performance using a K&C test bench as described in claim 1, characterized in that, The method includes conducting the experiment using friction disks with different coefficients of friction and obtaining the analysis report; The friction coefficient of the friction disk ranges from 0.1 to 1.

3.

4. The test method for verifying braking performance using a K&C test bench as described in claim 1, characterized in that, The friction coefficients of the friction disks on the four corner platforms are the same.

5. The test method for verifying braking performance using a K&C test bench as described in claim 1, characterized in that, The diameter of the friction disk is not less than 50 cm.

6. The test method for verifying braking performance using a K&C test bench as described in claim 1, characterized in that, The longitudinal forces applied to the two corner platforms corresponding to the two front wheels are the same, and the longitudinal forces applied to the two corner platforms corresponding to the two rear wheels are the same.

7. The test method for verifying braking performance using a K&C test bench as described in claim 1, characterized in that, During the test, before the abrupt change in the first curve and the second curve, the braking force output by the braking system was the same as the friction force. During the test, if either the first curve or the second curve has a sudden change, the braking force and angular platform displacement corresponding to the sudden change point are calculated. The braking force is used as the maximum braking force and maximum braking distance of the braking system, and the analysis report includes the maximum braking force and maximum braking distance.

8. The test method for verifying braking performance using a K&C test bench as described in claim 1, characterized in that, The braking force output by the braking systems on the two front wheels and the braking force output by the braking systems on the two rear wheels are calculated using the following formulas: in, Used to indicate the braking force output by the braking system on the two front wheels; Used to indicate the braking force output by the braking system on the two rear wheels; G is used to represent the total weight of the vehicle; L is used to indicate the vehicle's wheelbase; Used to indicate the horizontal distance from the vehicle's center of gravity to the center line of the vehicle's front axle; Used to indicate the horizontal distance from the vehicle's center of gravity to the center line of the rear axle; Used to represent the coefficient of friction of a friction disk; Used to indicate the height of a car's center of gravity.

9. A test system for verifying braking performance using a K&C test bench, the system comprising a K&C test bench; characterized in that, The system also includes: The robotic arm is used to place the four wheels of the test vehicle on the four corner platforms after friction discs are set on the upper surfaces of the four corner platforms that contact the wheels. It is also used to set angle sensors at the wheel centers. The control component is used to fix the vehicle body and steering wheel, and after applying maximum braking force to the brake pedal, controls the four corner platforms to move backward relative to the vehicle body, and gradually increases the longitudinal force of the four corner platforms on the four wheels during the movement. The processing component is used to obtain the frictional force applied to the wheel by the angular platform based on the friction coefficient of the friction disk and the longitudinal force, and to collect the rotation angle of the wheel center through multiple angle sensors; it is also used to obtain an analysis report on vehicle braking performance verification based on the frictional force, rotation angle, angular platform displacement, and braking force output by the test vehicle; the specific steps of obtaining the analysis report on vehicle braking performance verification based on the frictional force, rotation angle, angular platform displacement, and braking force output by the test vehicle include the following: A first curve is generated with the frictional force as the abscissa and the rotation angle as the ordinate; A second curve is generated with the frictional force as the abscissa and the angular platform displacement as the ordinate; Determine the abrupt changes in the first and second curves: If neither the first curve nor the second curve shows any abrupt change, then the analysis report indicates that the braking force of the braking system meets the standard. If the first curve shows a sudden change and the second curve does not, then the analysis report indicates that the braking force of the braking system is substandard. If the first curve has no sudden change but the second curve has a sudden change, then the analysis report indicates that the braking force of the braking system meets the standard and the friction between the tire and the ground is insufficient. If both the first and second curves show abrupt changes, the analysis report indicates that the braking force of the braking system is insufficient and the friction between the tires and the ground is inadequate.

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