Novel driving unit hybrid braking force distribution test method and system

Abstract

The invention provides a novel driving unit hybrid braking force distribution testing method and system, and relates to the technical field of automobile braking performance testing. The method comprises the steps that multiple braking working conditions are set; under each braking working condition, simulation testing is carried out based on the whole vehicle dynamics model and the input parameters, and simulation performance data of the novel driving unit under each braking working condition are obtained; converting a load curve obtained by the simulation test into a driving parameter of the novel driving unit; brake actual measurement is conducted on the novel driving unit based on the driving parameters, and actual measurement performance data are obtained; calculating a root-mean-square error of the simulation performance data and the actual measurement performance data, and if the root-mean-square error is smaller than a preset threshold value, completing the test; and otherwise, taking the wheel end external force data obtained in the actual measurement process as a modified input parameter, and performing the simulation test again based on the whole vehicle dynamics model and the modified input parameter until the root-mean-square error is smaller than the preset threshold value. Technical support can be provided for vehicle type braking force distribution strategy development.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile braking performance testing, and in particular to a new driving unit hybrid braking force distribution test method and system. BACKGROUND

[0002] The new driving unit (corner module) is a highly integrated intelligent chassis technology that integrates driving, steering, braking and suspension systems into one wheel to achieve multi-system collaborative control, thereby improving vehicle energy efficiency and dynamic performance and providing key technical support for future intelligent transportation and autonomous driving. The electronic mechanical braking system is a key subsystem of the new driving unit, which usually includes two sources of braking force: a mechanical friction braking unit and a motor regenerative braking unit. Motor braking can maximize energy recovery and reduce brake wear, but is limited by motor power and battery state; friction braking can provide stable and reliable braking force, but reduces energy recovery rate and increases wear. The key to the distribution strategy is to dynamically coordinate the proportion of the two, which is adjusted in real time based on parameters such as vehicle speed, deceleration, battery state, etc. through intelligent algorithms to ensure braking efficiency while improving energy recovery rate, so it directly affects the safety, energy recovery efficiency and driving experience of the vehicle.

[0003] Currently, there is a lack of standardized test methods for the dynamic coupling characteristics of the two braking force sources in the industry, therefore, a new driving unit hybrid braking force distribution test method for multiple working conditions needs to be developed to systematically verify the performance of the electronic mechanical braking system in the new driving unit, thereby promoting technological innovation in China's new energy vehicle industry. SUMMARY

[0004] To solve the above technical problems, the present application provides a new driving unit hybrid braking force distribution test method and system.

[0005] According to an aspect of the present application, a new driving unit hybrid braking force distribution test method is provided, which comprises: setting multiple braking conditions; under each braking condition, performing simulation testing based on a vehicle dynamics model and input parameters to obtain simulation performance data of the new driving unit under each braking condition; the simulation performance data includes a load curve; converting the load curve obtained from the simulation testing into driving parameters for the new driving unit, the driving parameters being used to apply dynamic load to the new driving unit; under each braking condition, performing braking measurement on the new driving unit based on the driving parameters to obtain measured performance data of the new driving unit under each braking condition; Calculate the root mean square error (RMSE) of the simulated performance data and the measured performance data. If the RMSE is less than a preset threshold, the test is completed. Otherwise, use the wheel-end external force data obtained during the actual test as the modified input parameters, and re-perform the simulation test based on the whole vehicle dynamics model and the modified input parameters. Repeat all the above steps until the RMSE is less than the preset threshold.

[0006] Furthermore, the braking conditions include: emergency full braking, medium-speed partial braking, low-speed energy recovery, and continuous braking deterioration. The emergency full braking condition is as follows: when the vehicle is traveling at a high speed on a smooth road, the initial braking time of depressing the brake pedal does not exceed a preset time, the pedal opening is 100%, until the vehicle speed drops to 0. The medium-speed partial braking condition is as follows: when the vehicle is traveling at a medium speed on a smooth road, the initial braking time of depressing the brake pedal does not exceed a preset time, the pedal opening is 50%, until the vehicle speed drops to 0. The low-speed energy recovery condition is as follows: when the vehicle is traveling at a low speed on a smooth road, the accelerator pedal is released until the vehicle enters idle mode for a certain period. The continuous braking deterioration condition is as follows: when the vehicle is traveling at a high initial speed on a smooth road, braking with 80% pedal opening is performed every 30 seconds, and this braking is repeated several times.

[0007] Furthermore, the vehicle dynamics model is established based on the actual parameters of the target vehicle, including vehicle dimensions, mass, center of gravity position, moment of inertia, subsystem characteristics, suspension, and tire characteristics; the input parameters include throttle opening, brake opening, steering wheel angle, and road adhesion coefficient; the simulation performance data also includes: braking force curve, braking response time, motor torque response, vehicle deceleration, pitch, and roll angles.

[0008] Furthermore, the formula for calculating the root mean square error is as follows:

[0009] In the formula, N represents the total number of sampling times; Represents the i-th sampling time. Actual performance data, Represents the i-th sampling time. The simulation performance data.

[0010] Furthermore, the method also includes: testing each braking condition multiple times according to the test method, and averaging the results of the multiple tests to obtain the final measured performance data; the final measured performance data includes: braking distance, braking response time, motor power, total braking force, single wheel lateral offset angle, maximum braking force during the first braking, maximum braking force during the nth consecutive braking, and peak motor torque before and after the test.

[0011] Furthermore, the method also includes: after obtaining the final measured performance data, evaluating the braking performance of the new driving unit based on the final measured performance data. Evaluation indicators for excellent braking performance include: the braking distance is less than a preset distance threshold; the braking response time is less than a preset time threshold; the regenerative braking contribution rate is calculated based on the ratio of motor power to total braking force, and the regenerative braking contribution rate is greater than a preset contribution threshold; the single-wheel lateral offset angle is less than a preset angle threshold; the difference between the maximum braking force during the first braking and the maximum braking force during the nth consecutive braking is calculated, and the braking force attenuation rate is calculated based on the ratio of the difference to the maximum braking force during the first braking, and the braking force attenuation rate is less than a preset braking attenuation threshold; the motor torque attenuation rate is calculated based on the peak motor torque before and after the test, and the motor torque attenuation rate is less than a preset torque attenuation threshold.

[0012] According to another aspect of the present invention, a novel hybrid braking force distribution test system for a driving unit is proposed for implementing the method described above; the system includes: The simulation test module is configured to set multiple braking conditions; under each braking condition, simulation tests are performed based on the vehicle dynamics model and input parameters to obtain simulation performance data of the new driving unit under each braking condition; the simulation performance data includes load curves. The test module is configured to convert the load curves obtained from simulation tests into driving parameters for the novel driving unit, which are used to apply dynamic loads to the novel driving unit. Under each braking condition, the new driving unit is subjected to actual braking tests based on the driving parameters to obtain the actual performance data of the new driving unit under each braking condition. The error comparison module is configured to calculate the root mean square error of the simulated performance data and the measured performance data. If the root mean square error is less than a preset threshold, the test is completed; otherwise, the wheel end external force data obtained during the actual test is used as the modified input parameters, and the simulation test is re-performed based on the whole vehicle dynamics model and the modified input parameters. All the above steps are repeated until the root mean square error is less than the preset threshold.

[0013] According to another aspect of the invention, an electronic device is also proposed, comprising a memory, a processor, and a computer program; wherein the computer program is stored in the memory and configured to be executed by the processor to implement a novel hybrid braking force distribution test method for a driving unit as described above.

[0014] According to another aspect of the invention, a computer-readable storage medium is also provided, on which a computer program is stored; the computer program is executed by a processor to implement a novel driving unit hybrid braking force distribution test method as described above.

[0015] The embodiments of the present invention have the following technical effects: This invention provides a novel method and system for testing hybrid braking force distribution in a driving unit. By testing this novel hybrid braking force distribution, it can provide technical support for the development of vehicle braking force distribution strategies, optimize braking force distribution, effectively improve vehicle safety, economy, and comfort, shorten the R&D cycle, and reduce R&D costs. Establishing a scientific testing process and indicators fills the gap in industry standards for electromechanical composite braking testing, promotes the development of new energy vehicle braking systems towards greater safety, efficiency, and intelligence, and has guiding significance for promoting technological upgrading in the automotive industry. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart of a novel hybrid braking force distribution test method for a driving unit as described in this invention; Figure 2 This is a simplified structural diagram of the novel driving unit test bench in an embodiment of the present invention; Figure 3 This is another flowchart of a novel hybrid braking force distribution test method for a driving unit as described in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are part of this invention.

[0019] This invention proposes a novel test method for the distribution of hybrid braking force in a driving unit, such as... Figure 1 As shown, the method includes: Multiple braking conditions can be set; Under each braking condition, simulation tests are conducted based on the vehicle dynamics model and input parameters to obtain simulation performance data of the new driving unit under each braking condition; the simulation performance data includes load curves. The load curves obtained from simulation tests are converted into driving parameters for the new driving unit, which are used to apply dynamic loads to the new driving unit. Under each braking condition, the new driving unit is subjected to actual braking tests based on the driving parameters to obtain the actual performance data of the new driving unit under each braking condition. Calculate the root mean square error (RMSE) of the simulated performance data and the measured performance data. If the RMSE is less than a preset threshold, the test is completed. Otherwise, use the wheel-end external force data obtained during the actual test as the modified input parameters, and re-perform the simulation test based on the whole vehicle dynamics model and the modified input parameters. Repeat all the above steps until the RMSE is less than the preset threshold.

[0020] In this embodiment, optionally, the braking conditions include: emergency full braking condition, medium-speed partial braking condition, low-speed energy recovery condition, and continuous braking deterioration condition; the emergency full braking condition is: when the vehicle is traveling at a high speed on a flat road, the start time of pressing the brake pedal does not exceed a preset time, the pedal opening is 100%, until the vehicle speed drops to 0; the medium-speed partial braking condition is: when the vehicle is traveling at a medium speed on a flat road, the start time of pressing the brake pedal does not exceed a preset time, the pedal opening is 50%, until the vehicle speed drops to 0; the low-speed energy recovery condition is: when the vehicle is traveling at a low speed on a flat road, the accelerator pedal is released until the vehicle enters an idling state for a certain period of time; the continuous braking deterioration condition is: when the vehicle is traveling at a high initial speed on a flat road, braking with 80% pedal opening is performed every 30 seconds, and the braking is repeated several times.

[0021] In this embodiment, optionally, the vehicle dynamics model is established based on the actual parameters of the target vehicle, including vehicle size, mass, center of gravity position, moment of inertia, subsystem characteristics, suspension and tire characteristics; the input parameters include throttle opening, brake opening, steering wheel angle and road adhesion coefficient; the simulation performance data also includes: braking force curve, braking response time, motor torque response, vehicle deceleration, pitch and roll angles.

[0022] In this embodiment, optionally, the method further includes: testing each braking condition multiple times according to the test method, and averaging the results of the multiple tests to obtain the final measured performance data; the final measured performance data includes: braking distance, braking response time, motor power, total braking force, single wheel lateral offset angle, maximum braking force during the first braking, maximum braking force during the nth continuous braking, and peak motor torque before and after the test.

[0023] In this embodiment, optionally, the method further includes: after obtaining the final valid data, evaluating the braking performance of the new driving unit based on the final valid data, wherein the evaluation indicators for excellent braking performance include: the braking distance is less than a preset distance threshold; the braking response time is less than a preset time threshold; the regenerative braking contribution rate is calculated based on the ratio of motor power to total braking force, and the regenerative braking contribution rate is greater than a preset contribution threshold; the single-wheel lateral offset angle is less than a preset angle threshold; the difference between the maximum braking force during the first braking and the maximum braking force during the nth consecutive braking is calculated, and the braking force attenuation rate is calculated based on the ratio of the difference to the maximum braking force during the first braking, and the braking force attenuation rate is less than a preset braking attenuation threshold; the motor torque attenuation rate is calculated based on the peak motor torque before and after the test, and the motor torque attenuation rate is less than a preset torque attenuation threshold. Specific Implementation Example 1 Figure 2 This is a schematic diagram of a test bench for a new type of driving unit. The new driving unit is placed on a road load simulation mechanism, and both the road load simulation mechanism and the motor are connected to a control console.

[0025] like Figure 3 As shown, this embodiment uses the development of a vehicle equipped with a novel driving unit (corner module) as an example to illustrate a novel driving unit hybrid braking force distribution test method, including the following steps: Step 1: Set the braking conditions as follows: ① Emergency full braking condition: The vehicle is traveling at a constant speed of 100±2 km / h on a flat Class B road. Immediately press the brake pedal (the start time does not exceed 0.2s), with the pedal opening at 100%, until the vehicle speed drops to 0. ② Medium-speed partial braking condition: The vehicle is traveling at a constant speed of 60±2 km / h on a flat Class B road surface. Immediately press the brake pedal (the start-up time does not exceed 0.2s), with the pedal opening at 50%, until the vehicle speed drops to 0. ③Low-speed energy recovery condition: The vehicle travels at a constant speed of 30±2 km / h on a flat Class B road surface. Release the accelerator pedal until the vehicle enters idle state for 3 seconds. ④ Continuous braking degradation condition: The vehicle travels at a constant initial speed of 100±2 km / h on a smooth Class B road surface, and brakes at 80% pedal opening every 30 seconds, repeating 10 times.

[0026] Step Two: Based on the test conditions, perform simulation tests on the vehicle dynamics model, output simulation data, and extract the time-domain curves of the loads on each wheel of the vehicle. Use simulation software to construct a vehicle dynamics model that matches the novel driving unit under test. This model is based on the actual parameters of the target vehicle, including overall vehicle dimensions, mass, center of gravity position, moment of inertia, subsystem characteristics, suspension, and tire characteristics.

[0027] Define the input and output interfaces of the vehicle dynamics model. The input interface receives test condition parameters, including throttle opening, brake opening, steering wheel angle and road adhesion coefficient. The output interface includes wheel loads, braking force curves, braking response time, motor torque response, vehicle deceleration, pitch and roll angles, etc.

[0028] Step 3: Convert the operating conditions from Step 1 into corresponding time-domain parameters and input them into the vehicle dynamics model of the new driving unit. Run the operating conditions and record and analyze the various parameters of the preset output interface of the simulation output.

[0029] Step 4: Secure the new driving unit to the tracked platform, ensuring the tires are in contact with the track surface. Connect the suspension mounting points to the tooling fixture, and adjust the suspension spring compression by tightening bolts to simulate wheel load. The fixture structure provides a movement space of ±30° for the tires' steering angle. It is connected to the track platform base by bolts and reinforced with ropes at the four corners of the track platform. The new driving unit is connected to a mobile battery simulator, with control signals input from a host computer. An external water pump establishes a circulating cooling system to ensure thermal management requirements.

[0030] Step 5: Perform bench testing based on the operating data from Steps 1 and 2. The extracted time-domain curves of the wheel loads on each wheel of the vehicle are imported into the control system of the drum test bench as the target load spectrum. The control system generates corresponding loading commands based on these time-domain curves, driving the vertical loading actuators of the test bench to apply dynamic loads to the suspension supports of the new driving unit. This ensures that the force between the tires and the drum surface changes over time in accordance with the simulated wheel load curves, thereby reproducing the dynamic load changes caused by acceleration, braking, steering, and road surface excitation during actual vehicle operation.

[0031] After completing the bench parameter debugging, start the bench test and run the test conditions to obtain the measured performance data, including but not limited to: motor output torque, motor speed, phase current, bus voltage, controller temperature, motor winding temperature, force on the reducer output end, and key physical quantities such as longitudinal force, lateral force and rotation torque at the tire grounding center.

[0032] Step Six: Compare the measured performance data with the simulation data: If the error exceeds the preset threshold, proceed to step seven for model correction. Key performance dimensions are selected for item-by-item comparison, including maximum braking force, motor power, and vehicle deceleration. The root mean square error (RMSE) is calculated using the following formula:

[0033] In the formula, N represents the total number of sampling times; Represents the i-th sampling time. Actual performance data, Represents the i-th sampling time. The simulation performance data.

[0034] The final judgment logic is as follows: if the RMSE of the measured and simulated data of each wheel end is not greater than 10%, then proceed to step eight; if the error of any wheel end is greater than 10%, then proceed to step seven.

[0035] Step 7: Replace the measured external forces at the wheel ends. When the error exceeds the limit, it is determined that the boundary conditions or system response characteristics of the current simulation model deviate significantly from the actual physical system. At this time, the wheel end external force data (including vertical force, longitudinal force, lateral force, and rotational torque) obtained during the actual measurement process is used as a new input signal and re-imported into the whole vehicle dynamics model established in Step 2 to replace the theoretical load boundary conditions at the corresponding wheel ends in the original simulation model. By rerunning the simulation, the time-domain distribution of the load on each wheel is updated, and a corrected load spectrum is generated. Based on the updated time-domain curve of the wheel load, bench testing is performed again. This process forms a closed-loop iterative mechanism of "simulation-bench testing-data feedback-model correction", continuously optimizing the accuracy of the simulation model until the comparison error between the measured performance data and the simulation data on key indicators converges to within the preset threshold.

[0036] Step 8: Once the error is within the limit, proceed to the performance evaluation stage. Tests are conducted sequentially on each wheel end. The completion of all tests constitutes one full test. At least three tests are performed under each working condition. After obtaining three sets of valid data, key performance indicators are extracted and statistically analyzed. Evaluation indicators include: ① Braking distance: The straight-line distance traveled along the direction of travel from the moment the braking command is activated (brake pedal travel is 100% triggered) until the tested module comes to a complete stop. Based on GB 21670-2008 "Technical Requirements and Test Methods for Braking Systems of Passenger Cars", a braking distance of ≤12.5m (preset distance threshold) is set to meet the requirements.

[0037] ② Braking response time: The time difference between when the brake pedal is applied and when the new driving unit generates effective braking force; setting the hybrid braking response to ≤120ms (preset time threshold) meets the requirements.

[0038] ③ Regenerative braking contribution rate: The ratio of motor power to total braking force, used to measure the initiative and efficiency of regenerative energy recovery. The regenerative braking contribution rate is calculated according to the following formula:

[0039] In the formula, Cr represents the contribution rate of regenerative braking. , These are the power torque of the electric motor or the braking torque of the electric motor. Total braking force (including friction braking). This is the torque for traditional friction braking.

[0040] ④ Braking Stability: Since the test subject is a 1 / 4 chassis, i.e., a single-wheel system, it does not possess the lateral force and lateral angular velocity of a complete vehicle. Therefore, only the change in lateral sway angle during braking is used as the basis for stability assessment. The range of wheel deflection angle change around the vertical axis (Z-axis) during braking is used to evaluate the lateral instability caused by braking. The lateral offset angle of a single wheel should be ≤2.0° (preset angle threshold).

[0041] ⑤ Braking thermal fade performance: In the continuous braking thermal fade test, the system performance is evaluated through the following steps: (a) Initial state: Record the peak torque value when the motor winding temperature is ≤50℃ before the experiment; (b) Perform 10 cycles of 0.8g deceleration braking (15s interval); (c) Within 15 seconds of braking ending, record the surface temperature of the brake disc, read the current braking force, and calculate the braking force decay rate using the following formula. :

[0042] In the formula, This is the maximum braking force during the initial braking. This represents the maximum braking force during the nth consecutive braking action.

[0043] (d) Obtain motor controller data via CAN bus, read the current winding temperature and real-time peak torque value; calculate the motor torque attenuation rate. The formula is as follows:

[0044] In the formula, , These represent the peak torque of the motor before and after the experiment.

[0045] Referring to GB / T 18488.2-2015 "Motor Controllers for Electric Vehicles - Part 2: Test Methods", the standard final braking force attenuation rate is set to ≤30% (preset braking attenuation threshold), and the motor torque attenuation rate is set to ≤15% (preset torque attenuation threshold). After calculation, a test report is output.

[0046] According to another aspect of the present invention, a novel hybrid braking force distribution test system for a driving unit is proposed, for implementing the novel hybrid braking force distribution test method for a driving unit described above; the system includes: The simulation test module is configured to set multiple braking conditions; under each braking condition, simulation tests are performed based on the vehicle dynamics model and input parameters to obtain simulation performance data of the new driving unit under each braking condition; the simulation performance data includes load curves. The test module is configured to convert the load curves obtained from simulation tests into driving parameters for the novel driving unit, which are used to apply dynamic loads to the novel driving unit. Under each braking condition, the new driving unit is subjected to actual braking tests based on the driving parameters to obtain the actual performance data of the new driving unit under each braking condition. The error comparison module is configured to calculate the root mean square error of the simulated performance data and the measured performance data. If the root mean square error is less than a preset threshold, the test is completed; otherwise, the wheel end external force data obtained during the actual test is used as the modified input parameters, and the simulation test is re-performed based on the whole vehicle dynamics model and the modified input parameters. All the above steps are repeated until the root mean square error is less than the preset threshold.

[0047] The function of the novel driving unit hybrid braking force distribution test system described in this embodiment of the invention can be explained by the aforementioned novel driving unit hybrid braking force distribution test method. Therefore, for the parts not described in detail in the system embodiment, please refer to the above method embodiment, and they will not be repeated here.

[0048] Another embodiment of the present invention provides an electronic device, including: at least one processor and a memory storing a computer program; when the computer program is read and executed by the processor, the electronic device performs a novel driving unit hybrid braking force distribution test method as described above.

[0049] Another embodiment of the present invention provides a readable storage medium storing a computer program, which, when read and executed by an electronic device, causes the electronic device to perform a novel driving unit hybrid braking force distribution test method as described above.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A novel method for testing the distribution of hybrid braking force in a driving unit, characterized in that, include: Multiple braking conditions can be set; Under each braking condition, simulation tests are conducted based on the vehicle dynamics model and input parameters to obtain simulation performance data of the novel driving unit under each braking condition. The simulation performance data includes load curves. The vehicle dynamics model is established based on the actual parameters of the target vehicle, including vehicle dimensions, mass, center of gravity position, moment of inertia, subsystem characteristics, suspension, and tire characteristics. The input parameters include throttle opening, brake opening, steering wheel angle, and road adhesion coefficient. The simulation performance data also includes: braking force curve, braking response time, motor torque response, vehicle deceleration, pitch, and roll angles. The load curves obtained from simulation tests are converted into driving parameters for the new driving unit, which are used to apply dynamic loads to the new driving unit. Under each braking condition, the new driving unit is subjected to actual braking tests based on the driving parameters to obtain the actual performance data of the new driving unit under each braking condition. Calculate the root mean square error (RMSE) of the simulated performance data and the measured performance data. If the RMSE is less than a preset threshold, the test is completed. Otherwise, use the wheel-end external force data obtained during the actual test as the modified input parameters, and re-perform the simulation test based on the whole vehicle dynamics model and the modified input parameters. Repeat all the above steps until the RMSE is less than the preset threshold.

2. The novel method for testing the hybrid braking force distribution of a driving unit according to claim 1, characterized in that, The braking conditions include: emergency full braking, medium-speed partial braking, low-speed energy recovery, and continuous braking deterioration. The emergency full braking condition is as follows: when the vehicle is traveling at a high speed on a smooth road, the initial braking time of depressing the brake pedal does not exceed a preset time, the pedal opening is 100%, and the vehicle speed drops to 0. The medium-speed partial braking condition is as follows: when the vehicle is traveling at a medium speed on a smooth road, the initial braking time of depressing the brake pedal does not exceed a preset time, the pedal opening is 50%, and the vehicle speed drops to 0. The low-speed energy recovery condition is as follows: when the vehicle is traveling at a low speed on a smooth road, the accelerator pedal is released until the vehicle enters idle for a preset time. The continuous braking deterioration condition is as follows: when the vehicle is traveling at a high initial speed on a smooth road, braking with 80% pedal opening is performed every 30 seconds, and this braking is repeated several times.

3. The novel method for testing the hybrid braking force distribution of a driving unit according to claim 2, characterized in that, The formula for calculating the root mean square error is: ； In the formula, N represents the total number of sampling times; Represents the i-th sampling time. Actual performance data, Represents the i-th sampling time. The simulation performance data.

4. The novel method for testing the hybrid braking force distribution of a driving unit according to claim 1, characterized in that, The method further includes: testing each braking condition multiple times according to the test method, and averaging the results of multiple tests to obtain the final measured performance data; the final measured performance data includes: braking distance, braking response time, motor power, total braking force, single wheel lateral offset angle, maximum braking force during the first braking, maximum braking force during the nth consecutive braking, and peak motor torque before and after the test.

5. The novel method for testing the hybrid braking force distribution of a driving unit according to claim 4, characterized in that, The method further includes: after obtaining the final measured performance data, evaluating the braking performance of the new driving unit based on the final measured performance data. Evaluation indicators for excellent braking performance include: the braking distance is less than a preset distance threshold; the braking response time is less than a preset time threshold; the regenerative braking contribution rate is calculated based on the ratio of motor power to total braking force, and the regenerative braking contribution rate is greater than a preset contribution threshold; the single-wheel lateral offset angle is less than a preset angle threshold; the difference between the maximum braking force during the first braking and the maximum braking force during the nth consecutive braking is calculated, and the braking force attenuation rate is calculated based on the ratio of the difference to the maximum braking force during the first braking, and the braking force attenuation rate is less than a preset braking attenuation threshold; the motor torque attenuation rate is calculated based on the peak motor torque before and after the test, and the motor torque attenuation rate is less than a preset torque attenuation threshold.

6. A novel hybrid braking force distribution test system for a driving unit, used to implement the method according to any one of claims 1-5, characterized in that, The system includes: The simulation test module is configured to set multiple braking conditions; under each braking condition, simulation tests are performed based on the dynamic model of the whole vehicle to obtain the simulation curve of the load on each wheel changing with time under each braking condition. The actual measurement module is configured to process the simulation curve of the load on each wheel changing with time to obtain the actual braking control quantity; under each braking condition, the actual braking measurement is performed on the new driving unit based on the actual braking control quantity to obtain the actual curve of the load on each wheel changing with time under each braking condition. The error comparison module is configured to calculate the braking error based on the simulation curve of the load on each wheel changing with time and the measured curve of the load on each wheel changing with time. If the braking error is less than a preset threshold, the test is completed; otherwise, the simulation test input parameters are modified and the simulation test is performed again. All the above steps are repeated until the braking error is less than the preset threshold.

7. An electronic device, characterized in that, It includes a memory, a processor, and a computer program; wherein the computer program is stored in the memory and configured to be executed by the processor to implement a novel driving unit hybrid braking force distribution test method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, It stores a computer program; the computer program is executed by a processor to implement a novel driving unit hybrid braking force distribution test method as described in any one of claims 1 to 5.

Images