A novel test method and system for hybrid braking force distribution of a running unit

Abstract

The application provides a novel driving unit hybrid braking force distribution test method and system, and relates to the technical field of automobile braking performance test. The method comprises the following steps: setting multiple braking conditions; under each braking condition, performing simulation test based on a vehicle dynamics model and input parameters to obtain simulation performance data of the novel driving unit under each braking condition; converting the load curve obtained by the simulation test into driving parameters of the novel driving unit; performing braking measurement on the novel driving unit based on the driving parameters to obtain measured performance data; calculating the root mean square error of the simulation performance data and the measured performance data, and if the root mean square error is less than a preset threshold, the test is completed; otherwise, the wheel end external force data obtained in the measurement process is taken as modified input parameters, and the simulation test is performed again based on the vehicle dynamics model and the modified input parameters until the root mean square error is less than the preset threshold. The application can provide technical support for the development of vehicle braking force distribution strategies.

Description

TECHNICAL FIELD

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

[0002] The new type of 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 type of 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 type of driving unit hybrid braking force distribution test method under multiple working conditions is needed to systematically verify the performance of the electronic mechanical braking system in the new type of 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 type of driving unit hybrid braking force distribution test method and system.

[0005] According to an aspect of the present application, a new type of driving unit hybrid braking force distribution test method is provided, which comprises:

[0006] Setting multiple braking conditions;

[0007] Under each braking condition, simulation testing is performed based on the vehicle dynamics model and input parameters to obtain simulation performance data of the new type of driving unit under each braking condition; the simulation performance data includes a load curve;

[0008] Converting the load curve obtained from the simulation testing into driving parameters for the new type of driving unit, the driving parameters being used to apply dynamic load to the new type of driving unit;

[0009] Under each braking condition, braking measurement is performed on the new type of driving unit based on the driving parameters to obtain measured performance data of the new type of driving unit under each braking condition;

[0010] a root mean square error of the calculated simulation performance data and the measured performance data is calculated, and if the root mean square error is less than a preset threshold, the test is completed; otherwise, wheel end external force data obtained in the measured process is taken as modified input parameters, and the simulation test is performed again based on the 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.

[0011] Further, the braking conditions include: an emergency full braking condition, a medium-speed partial braking condition, a low-speed energy recovery condition, and a continuous braking degradation condition. The emergency full braking condition is that when the vehicle travels at a high speed on a flat road, the take-off time of the brake pedal is not more than a preset time, the pedal opening degree is 100%, and the vehicle speed is reduced to 0. The medium-speed partial braking condition is that when the vehicle travels at a medium speed on a flat road, the take-off time of the brake pedal is not more than a preset time, the pedal opening degree is 50%, and the vehicle speed is reduced to 0. The low-speed energy recovery condition is that when the vehicle travels at a low speed on a flat road, the accelerator pedal is released until the vehicle enters an idle state for a certain time. The continuous braking degradation condition is that the vehicle travels at a high initial speed on a flat road, and the brake is applied at an opening degree of 80% every 30 seconds, and the brake is repeated for a plurality of times.

[0012] Further, the vehicle dynamics model is established based on actual parameters of the target vehicle, including vehicle size, mass, center of mass 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 further includes brake force curve, brake response time, motor torque response, vehicle deceleration, pitch and roll angle.

[0013] Further, the calculation formula of the root mean square error is:

[0014]

[0015] wherein N represents the total sampling time; represents the measured performance data at the i th sampling time represents the simulation performance data at the i th sampling time .

[0016] Further, the method further includes: each braking condition is tested multiple times according to the test method, and the final measured performance data is obtained by averaging the multiple test results. The final measured performance data includes: braking distance, brake response time, motor braking force, total braking force, single wheel lateral deflection angle, maximum braking force at first braking, maximum braking force at n th continuous braking, and motor peak torque before and after the test. ​

[0017] Further, the method further comprises: after obtaining the final measured performance data, evaluating the braking performance of the new driving unit based on the final measured performance data, and the evaluation indexes of 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; a regenerative braking contribution rate is calculated according to the ratio of the motor braking force to the 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; a difference between the maximum braking force at the first braking and the maximum braking force at the n th continuous braking is calculated, and a braking force decay rate is calculated according to the ratio of the difference to the maximum braking force at the first braking, and the braking force decay rate is less than a preset braking decay threshold; a motor torque decay rate is calculated based on the motor peak torque before and after the test, and the motor torque decay rate is less than a preset torque decay threshold.

[0018] According to another aspect of the present application, a new driving unit hybrid braking force distribution test system is provided for implementing the above-mentioned method; the system comprises:

[0019] a simulation test module configured to set multiple braking conditions; under each braking condition, simulation test is performed based on the vehicle dynamics model and the input parameters to obtain the simulation performance data of the new driving unit under each braking condition; the simulation performance data includes a load curve;

[0020] a measured module configured to convert the load curve obtained by the simulation test into driving parameters of the new driving unit, and the driving parameters are used to apply dynamic load to the new driving unit;

[0021] under each braking condition, the new driving unit is subjected to braking measurement based on the driving parameters to obtain the measured performance data of the new driving unit under each braking condition;

[0022] an error comparison module configured to calculate the root mean square error of the simulation performance data and the measured performance data, and 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 measurement is taken as the modified input parameters, and the simulation test is performed again based on the 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.

[0023] According to another aspect of the present application, an electronic device is also provided, which comprises a memory, a processor and a computer program; wherein the computer program is stored in the memory and is configured to be executed by the processor to implement a new driving unit hybrid braking force distribution test method as described above.

[0024] According to another aspect of the present application, a computer readable storage medium is also provided, which 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 above.

[0025] The embodiments of the present application have the following technical effects:

[0026] The present application provides a novel driving unit hybrid braking force distribution test method and system, which can provide technical support for vehicle braking force distribution strategy development by testing the new driving unit hybrid braking force distribution, optimize braking force distribution, effectively improve the safety, economy and comfort of the vehicle, shorten the development cycle, and reduce the development cost. Establish a scientific test process and index, fill the gap in the testing standard of mechanical and electrical composite braking in the industry, promote the development of new energy vehicle braking system to be safer, more efficient and more intelligent, and has guiding significance for promoting the upgrading of automobile industry technology. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0028] Figure 1 is a flowchart of a novel driving unit hybrid braking force distribution test method according to the present application;

[0029] Figure 2 is a simple structure schematic diagram of a novel driving unit test bench in the embodiments of the present application;

[0030] Figure 3 is another flowchart of a novel driving unit hybrid braking force distribution test method according to the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present application more clear, the technical scheme of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the present application.

[0032] The present application provides a novel driving unit hybrid braking force distribution test method, as shown in Figure 1 The method comprises:

[0033] Multiple braking conditions can be set;

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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

[0043] 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.

[0044] 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:

[0045] Step 1: Set the braking conditions as follows:

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Step Six: Compare the measured performance data with the simulation data:

[0057] 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:

[0058]

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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:

[0063] 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.

[0064] 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.

[0065] 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:

[0066]

[0067] 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.

[0068] 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).

[0069] ⑤ Braking thermal fade performance: In the continuous braking thermal fade test, the system performance is evaluated through the following steps:

[0070] (a) Initial state: Record the peak torque value when the motor winding temperature is ≤50℃ before the experiment;

[0071] (b) Perform 10 cycles of 0.8g deceleration braking (15s interval);

[0072] (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. :

[0073]

[0074] 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.

[0075] (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:

[0076]

[0077] In the formula, , These represent the peak torque of the motor before and after the experiment.

[0078] 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.

[0079] 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:

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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; 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. 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 vehicle dynamics model and the modified input parameters. Repeat all the above steps except for setting multiple braking conditions 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 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.

3. 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.

4. The novel method for testing the hybrid braking force distribution of a driving unit according to claim 3, 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.

5. A novel hybrid braking force distribution test system for a driving unit, used to implement the method according to any one of claims 1-4, 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.

6. 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 4.

7. 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 4.

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