A road environment simulation control method and system for a new energy vehicle test bench

Abstract

The present application relates to the field of new energy vehicle test bench control, in particular to a road environment simulation control method and system for a new energy vehicle test bench, comprising: S1, calculating the theoretical total road resistance and the predicted comprehensive friction loss of the target road, summing to obtain the initial torque of the dynamometer motor; obtaining the vehicle driving force; S2, calculating the actual road resistance based on the vehicle longitudinal mechanics model, subtracting the vehicle driving force to obtain the vehicle force deviation, if the slope correction condition is met, then calculating the slope angle correction amount through the deviation, updating the target slope, and adjusting the drum height difference to realize slope simulation; calculating the deviation between the predicted and actual comprehensive friction loss as the bench loss deviation, weighting and fusing it with the vehicle force deviation into a comprehensive deviation signal; when the comprehensive deviation exceeds the set threshold, generating a torque correction amount, superimposing it with the initial torque to obtain the final target torque of the dynamometer motor. The present application makes the error correction more accurate and efficient, and improves the stability of the test bench.

Description

Technical Field

[0001] This invention relates to the field of control technology for new energy vehicle test benches, specifically to a road environment simulation control method and system for new energy vehicle test benches. Background Technology

[0002] The test bench provides a realistic testing environment for the new energy vehicles being tested by simulating the slope resistance, rolling resistance, and air resistance encountered by vehicles when driving on real roads.

[0003] In existing technologies, road resistance simulation typically employs control methods based on fixed parameter lookup tables or simple physical models. However, this approach cannot accurately compensate for the complex mechanical friction losses of the test bench itself, as well as the energy losses caused by slippage between the tire and the roller during dynamic testing. These unaccounted losses can lead to inaccurate test results. Secondly, traditional slope simulations are mostly static or segmented, making it impossible to perform high-precision, dynamic calibration of the slope during testing. Summary of the Invention

[0004] This invention provides a road environment simulation control method and system for a new energy vehicle test bench.

[0005] The technical solution of this invention is as follows:

[0006] A method for simulating and controlling the road environment of a new energy vehicle test bench includes:

[0007] S1. Obtain the theoretical total road resistance and predicted comprehensive friction loss of the target road environment. Add the two together to obtain the initial torque of the test bench dynamometer motor.

[0008] Obtain vehicle driving force.

[0009] S2. Based on the longitudinal mechanical model of the vehicle, obtain the actual road resistance, subtract the vehicle driving force, and obtain the vehicle force deviation. Determine whether the slope correction condition is met. If it is met, divide the vehicle force deviation by the product of the vehicle weight and the cosine value of the existing slope angle to obtain the slope angle correction amount. Add it to the existing slope angle to obtain the target slope. Based on the target slope, obtain the height difference of the target roller group on the test bench. Control the lifting platform to make the height difference of the test bench roller group reach the height difference of the target roller group.

[0010] The actual comprehensive friction loss is obtained, and the test bench loss deviation is obtained by subtracting the predicted comprehensive friction loss from the actual comprehensive friction loss. The test bench loss deviation and the vehicle force deviation are weighted and fused to obtain the comprehensive deviation signal. When the comprehensive deviation is greater than or equal to the first error, the torque correction amount is obtained based on the comprehensive deviation signal. The initial load and the torque correction amount are added together to obtain the target torque. The output of the test bench dynamometer motor is controlled to reach the target torque.

[0011] The slope correction condition is that the following conditions must be met simultaneously:

[0012] Vehicle speed fluctuation < vehicle speed threshold, acceleration < acceleration threshold, vehicle force deviation at consecutive times is greater than vehicle force deviation threshold, and the time interval between two consecutive slope correction operations is greater than the interval threshold.

[0013] In S2, the height difference of the target roller group on the test bench is obtained based on the target slope. The specific operation is as follows:

[0014] Based on the mechanical structure hard limit, a mechanical upper limit is set; based on the current vehicle speed, a dynamic amplitude that is inversely proportional to the vehicle speed is set; and based on the product of the existing slope angle change rate threshold and the time interval between adjacent batches, an interval amplitude threshold is set.

[0015] The minimum value among the mechanical upper limit, dynamic amplitude, and interval amplitude threshold is selected as the maximum value for a single height difference adjustment.

[0016] In S2, the torque correction amount is obtained based on the comprehensive deviation signal. The specific operation is as follows:

[0017] ,

[0018] in, This is the torque correction amount. , , They are the first coefficient, the second coefficient, and the third coefficient, respectively. , , These are the comprehensive deviation signal at the current time, the comprehensive deviation signal at the previous time, and the comprehensive deviation signal at the time before that, respectively.

[0019] In S2, the test bench wear deviation and vehicle stress deviation are weighted and fused to obtain a comprehensive deviation signal. Specifically, the weight of the vehicle stress deviation is greater than the weight of the test bench wear deviation.

[0020] The sum of the weights of the vehicle stress deviation and the bench wear deviation equals 1.

[0021] The specific method for obtaining the predicted comprehensive friction loss described in S1 is as follows: obtain the speed change curve of the roller group under the initial speed during free deceleration, calculate the internal friction overcome in this process, fit the functional relationship between internal friction and speed and the center distance of the roller group, and obtain the basic curve of internal friction loss.

[0022] By using the controlled variable method for tire pressure, vehicle axle load, mounting angle, and vehicle speed, the slip friction under each condition is obtained. Based on the wheel speed, the dynamic rolling radius of the tire, the speed of the roller assembly, and the radius of the roller assembly, the slip ratio is calculated, resulting in a slip friction loss model that combines slip ratio, mounting angle, and vehicle speed.

[0023] The predicted total friction loss is obtained by adding the internal friction loss and the sliding friction loss.

[0024] A road environment simulation control system for a new energy vehicle test bench, used to implement the aforementioned road environment simulation control method for a new energy vehicle test bench, includes:

[0025] The control module obtains the theoretical total road resistance and predicted comprehensive friction loss of the target road environment. The two are added together to obtain the initial torque of the test bench dynamometer motor.

[0026] Obtain vehicle driving force.

[0027] Based on the longitudinal mechanical model of the vehicle, the actual road resistance is obtained, the vehicle driving force is subtracted, and the vehicle force deviation is obtained. It is then determined whether the slope correction condition is met. If it is met, the vehicle force deviation is divided by the product of the vehicle weight and the cosine value of the existing slope angle to obtain the slope angle correction amount. This correction amount is added to the existing slope angle to obtain the target slope. Based on the target slope, the height difference of the target roller group on the test bench is obtained. The lifting platform is then controlled to make the height difference of the test bench roller group reach the target roller group height difference.

[0028] The actual comprehensive friction loss is obtained, and the test bench loss deviation is obtained by subtracting the predicted comprehensive friction loss from the actual comprehensive friction loss. The test bench loss deviation and the vehicle force deviation are weighted and fused to obtain the comprehensive deviation signal. When the comprehensive deviation is greater than or equal to the first error, the torque correction amount is obtained based on the comprehensive deviation signal. The initial load and the torque correction amount are added together to obtain the target torque. The output of the test bench dynamometer motor is controlled to reach the target torque.

[0029] The lifting platform is driven by hydraulic cylinders to ensure the vertical lifting of the roller assembly and receives instructions from the control module to adjust the height difference.

[0030] The roller assembly is located above the lifting platform, and its shaft is rigidly connected to the dynamometer motor via a coupling.

[0031] The dynamometer motor is located above the lifting platform. The rotor of the dynamometer motor is connected to the roller assembly. It receives instructions from the control module, changes the torque, and simulates road conditions.

[0032] The control module weights and fuses the test bench wear deviation and the vehicle stress deviation to obtain a comprehensive deviation signal. Specifically, the weight of the vehicle stress deviation is greater than the weight of the test bench wear deviation.

[0033] The sum of the weights of the vehicle stress deviation and the bench wear deviation equals 1.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This invention does not treat errors in a general way, but decomposes them into vehicle stress deviation and test bench wear deviation. By judging the former, slope correction is triggered, eliminating systematic steady-state errors at their source. This invention combines continuous deviation monitoring for batch adjustments, so that slope simulation is no longer a simple signal simulation, but based on real attitude changes.

[0036] This invention generates precise torque to drive a dynamometer motor. By calculating the test bench loss deviation and the vehicle's force deviation, and then weighting and fusing the two, a comprehensive deviation signal is obtained. When this deviation exceeds the allowable range, the required torque correction is calculated based on the comprehensive deviation signal and superimposed on the initial torque to form the final target torque. This enables the dynamometer motor to output torque quickly and accurately, thereby achieving high-fidelity dynamic reproduction of road loads. It ensures that the load force experienced by the vehicle on the test bench is highly consistent with the force state on a real road, providing a reliable load environment for vehicle performance testing. This makes torque correction more accurate and efficient, greatly improving the steady-state level of the control system.

[0037] Furthermore, the road resistance and slope angle generated by this invention can be used for subsequent vehicle testing, providing a reliable and efficient road environment for the test bench and reducing the risks of road surface testing. Attached Figure Description

[0038] In the attached diagram:

[0039] Figure 1 This is a schematic diagram of the test bench roller assembly.

[0040] The components represented by the various reference numerals in the diagram are:

[0041] 1. Lifting platform; 2. Roller assembly; 3. Dynamometer motor. Detailed Implementation

[0042] The technical solution of this invention is as follows:

[0043] A method for simulating and controlling the road environment of a new energy vehicle test bench includes:

[0044] Analyzing the driving dynamics characteristics, driver assistance system control strategies, and working principles of new energy vehicles, we determined benchtop testing items suitable for the autonomous driving functions of new energy vehicles. To simulate the road conditions of new energy vehicles during bench testing, we designed the following structure: Figure 1 The test bench shown.

[0045] During the whole vehicle bench test, traffic scene simulation is achieved through the visual scene restoration system and VRTS radar simulation system, and road condition simulation is achieved based on the high dynamic vehicle test bench. The longitudinal assisted driving function of the new energy vehicle under test is tested and evaluated by utilizing the real-time interaction between the new energy vehicle under test, the test bench and the scene.

[0046] S1. Obtain the theoretical total road resistance and predicted comprehensive friction loss of the target road environment. Add the two together to obtain the initial torque of the test bench dynamometer motor 3.

[0047] Obtain vehicle driving force.

[0048] Specifically, the method for predicting comprehensive friction loss is as follows: obtain the speed change curve of the roller group 2 when it decelerates freely at the initial speed, calculate the internal friction overcome in this process, fit the functional relationship between internal friction and speed and the center distance of roller group 2, and obtain the basic curve of internal friction loss.

[0049] The control variable method is used to obtain the slip friction under each condition, including tire pressure, vehicle axle load, placement angle, and vehicle speed. The slip ratio is calculated based on the wheel speed, the dynamic rolling radius of the tire, the speed of roller group 2, and the radius of roller group 2, resulting in a slip friction loss model with slip ratio, placement angle, and vehicle speed.

[0050] The predicted total friction loss is obtained by adding the internal friction loss and the sliding friction loss.

[0051] The total road resistance calculated based on the target road environment, plus the predicted comprehensive friction loss, is the initial torque of the dynamometer motor 3 on the test bench.

[0052] Input this initial torque onto the test bench to start the simulation, and obtain the vehicle's driving force after the simulation begins, providing a basis for subsequent simulation steps.

[0053] S2. Based on the longitudinal mechanical model of the vehicle, obtain the actual road resistance, subtract the vehicle driving force, and obtain the vehicle force deviation. Determine whether the slope correction condition is met. If it is met, divide the vehicle force deviation by the product of the vehicle weight and the cosine value of the existing slope angle to obtain the slope angle correction amount. Add it to the existing slope angle to obtain the target slope. Based on the target slope, obtain the height difference of the target roller group 2 on the test bench. Control the lifting platform 1 to make the height difference of the test bench roller group 2 reach the height difference of the target roller group 2.

[0054] The actual comprehensive friction loss is obtained, and the test bench loss deviation is obtained by subtracting the predicted comprehensive friction loss from the actual comprehensive friction loss. The test bench loss deviation and the vehicle force deviation are weighted and fused to obtain the comprehensive deviation signal. When the comprehensive deviation is greater than or equal to the first error, the torque correction amount is obtained based on the comprehensive deviation signal. The initial load and the torque correction amount are added together to obtain the target torque. The output of the test bench dynamometer motor 3 is controlled to reach the target torque.

[0055] The rolling resistance of a tire on the test bench roller assembly differs from that on an actual road. During the longitudinal movement of a new energy vehicle, the axle load and the slippage between the tire and the test bench roller assembly cause tire deformation at the contact surface, generating longitudinal forces. Based on test bench data, a tire characteristic curve is fitted to reflect the contact mechanism between the tire and the vehicle test bench. Based on the mathematical model of rolling resistance on the test bench and the longitudinal kinematic model of the new energy vehicle, a longitudinal dynamics model of the vehicle is constructed using a combination of theoretical analysis and fitting of test bench data.

[0056] Based on the current road environment and sensor data, the longitudinal mechanical model of the vehicle is substituted to obtain the actual road resistance of the new energy vehicle under the current test bench environment, which directly reflects the total resistance currently experienced by the vehicle.

[0057] Subtracting the vehicle's driving force yields the vehicle's force deviation, which quantifies the difference between the resistance applied by the simulated environment and the resistance actually felt by the vehicle.

[0058] If the force deviation of the vehicle is greater than 0, it indicates that the resistance of the current road environment is less than that of the target road environment, which means that the resistance simulated by the test bench is insufficient and needs to be increased.

[0059] If the force deviation of the vehicle is less than 0, it indicates that the simulated resistance is greater than the target road environment, which means that the resistance simulated by the test bench is excessive and needs to be reduced.

[0060] If the force deviation of the vehicle is approximately 0, it indicates that the simulated resistance meets the requirements and the simulation is accurate.

[0061] Furthermore, if the force deviation of the vehicle is not equal to 0, it is necessary to determine whether to perform slope correction. The core objective of slope correction is to eliminate systematic and continuous slope simulation errors caused by factors such as inaccurate initial slope calibration, long-term deformation of mechanical structure, or temperature drift.

[0062] This is a slow, high-precision calibration loop. It does not pursue a fast response, but rather determines whether the initial gradient setting is accurate by monitoring the long-term cumulative amount of force deviation on the vehicle, and then makes fine adjustments.

[0063] Determine if the following slope correction conditions are met simultaneously to ensure that slope correction is initiated only at appropriate times:

[0064] Vehicle speed fluctuation < vehicle speed threshold, acceleration < acceleration threshold, vehicle force deviation at consecutive times is greater than vehicle force deviation threshold, and the time interval between two consecutive slope correction operations is greater than the interval threshold.

[0065] Vehicle speed fluctuation is a steady-state criterion. The test bench must be in a steady state to avoid misjudging dynamic inertial force as slope error. Furthermore, vehicle speed fluctuation must be continuous. If it is only an instantaneous fluctuation, it may be an occasional situation caused by interference, which is not considered in this application.

[0066] There must be a minimum time interval between two consecutive slope correction operations to prevent the mechanism from operating too frequently.

[0067] When the above slope correction conditions are met, under constant speed, the main resistances of the vehicle are rolling resistance, air resistance, and slope resistance. Air resistance is determined by vehicle speed and is accurate, while rolling resistance is relatively stable. Therefore, the continuous deviation in vehicle force mainly originates from slope resistance error. The slope angle correction is calculated as follows:

[0068] ,

[0069] in Given the existing slope angle, For vehicle force deviation, This refers to the vehicle's weight.

[0070] The slope angle correction is added to the existing slope angle to obtain the target slope.

[0071] Based on the target slope, the height difference of the target roller group 2 on the test bench is obtained. The lifting platform 1 is controlled to make the height difference of the test roller group 2 reach the height difference of the target roller group 2. When adjusting the height of the roller group 2 to simulate the road slope, if the single adjustment is too large, it will cause a sudden change in the vehicle posture, which may cause the vehicle suspension system to extend and retract violently, causing impact or damage to the test vehicle, especially its chassis and sensors.

[0072] Drastic changes in attitude can also cause instability in the vehicle's dynamic response, rendering the test data for that period invalid. In extreme cases, it may compromise the vehicle's stability on the roller assembly, leading to a safety accident.

[0073] Therefore, this application first determines the maximum permissible adjustment range in a single instance. The maximum permissible adjustment range in a single instance is determined by the following factors, and the minimum value among them is taken:

[0074] Based on the mechanical structure hard limit, a mechanical upper limit is set; based on the current vehicle speed, a dynamic amplitude that is inversely proportional to the vehicle speed is set; and based on the product of the existing slope angle change rate threshold and the time interval between adjacent batches, an interval amplitude threshold is set.

[0075] The minimum value among the mechanical upper limit, dynamic amplitude, and interval amplitude threshold is selected as the maximum value for a single height difference adjustment.

[0076] The mechanical upper limit is an absolute safety limit, a physical upper limit determined by the mechanical structure of the test bench itself; the dynamic limit based on vehicle speed requires that the adjustment range be inversely proportional to the vehicle speed, and the higher the vehicle speed, the more cautious the adjustment must be; the limit based on the existing slope angle change rate is to prevent the cumulative change from being too rapid during continuous adjustment, so the change rate between adjacent batches needs to be limited.

[0077] After slope correction, it is also necessary to obtain the actual comprehensive friction loss. The predicted comprehensive friction loss minus the actual comprehensive friction loss is used to obtain the test bench wear deviation. The test bench wear deviation and the vehicle stress deviation are weighted and fused to obtain the comprehensive deviation signal. The specific weighting rules for the test bench wear deviation and the vehicle stress deviation are as follows: the weight of the vehicle stress deviation is greater than the weight of the test bench wear deviation, and the sum of the weights of the vehicle stress deviation and the test bench wear deviation is equal to 1.

[0078] This is because the deviation in vehicle stress is the ultimate goal that needs to be corrected, while the deviation in bench wear is only a secondary cause of the error in that goal.

[0079] Vehicle force deviation is a result that directly reflects the accuracy of the simulation, i.e. whether the road resistance actually felt by the vehicle is consistent with the theoretical value. The most fundamental task of this application is to eliminate this deviation.

[0080] Bench wear deviation is a secondary cause; it only indicates inaccuracies within the test bench. Correcting it is for optimizing control and making the test bench more accurate. Giving it more weight, a momentary, unreliable deviation measurement could cause severe disturbances to the overall system, ultimately affecting stability and accuracy.

[0081] The purpose of this invention is to quickly and smoothly compensate for the deviation in road resistance simulation caused by errors, acceleration / deceleration dynamic conditions, and high-frequency disturbances.

[0082] For this purpose, the weighted fusion-derived composite bias signal can be regarded as a force that needs to be quickly counteracted.

[0083] Before processing the comprehensive deviation signal, a first-order Butterworth filter is used to filter out high-frequency noise caused by mechanical vibration of the test bench. The cutoff frequency is usually set to 10-20Hz, which is much higher than the main frequency of the vehicle's longitudinal dynamics, to ensure signal quality.

[0084] A first error is set. When the overall deviation is less than the first error, it means that the deviation is within an acceptable range, and no torque correction is performed. This can avoid the test bench from frequently operating near the zero point, reduce mechanical wear and actuator fatigue, and improve system stability.

[0085] When the overall deviation is greater than or equal to the first error, the PID control algorithm is used to adjust the torque. The PID control algorithm has a simple structure, fast response to dynamic signals, and is mature in practical engineering applications. It is highly reliable and easy to implement in control systems.

[0086] In its implementation, this application employs incremental PID control, which outputs the increment of the control quantity, offering better fault tolerance and preventing integral saturation. The specific operation is as follows:

[0087] ,

[0088] in, This is the torque correction amount. , , They are the first coefficient, the second coefficient, and the third coefficient, respectively. , , These are the comprehensive deviation signal at the current time, the comprehensive deviation signal at the previous time, and the comprehensive deviation signal at the time before that, respectively.

[0089] It mainly affects the response speed; the larger the value, the faster the response, but too large a value can cause oscillation. It is used to eliminate steady-state error. For persistent small deviations, it gradually accumulates and outputs a correction amount. However, if the amount is too large, it can easily lead to integral saturation, resulting in overshoot and oscillation. Predictive correction based on the changing trend of the overall deviation signal helps suppress overshoot and improve system stability, but it is sensitive to noise and is usually used in conjunction with filtering.

[0090] As a further optimization, two groups were set up. , , One set is used for uniform motion. A slightly larger value can be used to minimize the steady-state error, meaning the current moment's comprehensive deviation signal has the largest proportion, and the torque correction is obtained primarily from the real-time comprehensive deviation signal; another set... , , For situations involving acceleration, and Higher weight, Reduce or freeze to suppress integral saturation.

[0091] The initial torque and the torque correction amount are added together to obtain the target torque, and the output of the dynamometer motor 3 on the test bench is controlled to reach the target torque.

[0092] The ultimate goal of this step is to generate precise torque to drive the dynamometer motor 3. By calculating the bench loss deviation and the vehicle force deviation, and then weighting and fusing them, a comprehensive deviation signal is obtained. When this deviation exceeds the allowable range, the required torque correction is calculated based on the comprehensive deviation signal and superimposed on the initial torque to form the final target torque. This ensures that the torque output by the dynamometer motor 3 is fast and accurate, thereby achieving high-fidelity dynamic reproduction of road loads. It ensures that the load force experienced by the vehicle on the test bench is highly consistent with the force state on a real road, providing a reliable load environment for vehicle performance testing.

[0093] A road environment simulation control system for a new energy vehicle test bench, used to implement the aforementioned road environment simulation control method for a new energy vehicle test bench, includes:

[0094] The control module obtains the theoretical total road resistance and predicted comprehensive friction loss of the target road environment. The two are added together to obtain the initial torque of the test bench dynamometer motor 3.

[0095] Obtain vehicle driving force.

[0096] Based on the longitudinal mechanical model of the vehicle, the actual road resistance is obtained, the vehicle driving force is subtracted, and the vehicle force deviation is obtained. It is then determined whether the slope correction condition is met. If it is met, the vehicle force deviation is divided by the product of the vehicle weight and the cosine value of the existing slope angle to obtain the slope angle correction amount. This correction amount is added to the existing slope angle to obtain the target slope. Based on the target slope, the height difference of the target roller group 2 on the test bench is obtained. The lifting platform 1 is controlled to make the height difference of the test bench roller group 2 reach the height difference of the target roller group 2.

[0097] The actual comprehensive friction loss is obtained, and the test bench loss deviation is obtained by subtracting the predicted comprehensive friction loss from the actual comprehensive friction loss. The test bench loss deviation and the vehicle force deviation are weighted and fused to obtain the comprehensive deviation signal. When the comprehensive deviation is greater than or equal to the first error, the torque correction amount is obtained based on the comprehensive deviation signal. The initial load and the torque correction amount are added together to obtain the target torque. The output of the test bench dynamometer motor 3 is controlled to reach the target torque.

[0098] The lifting platform 1 is driven by a hydraulic cylinder to ensure that the roller assembly 2 is raised and lowered vertically, and receives instructions from the control module to adjust the height difference.

[0099] Roller assembly 2 is located above lifting platform 1, and the shaft of roller assembly 2 is rigidly connected to dynamometer motor 3 through coupling.

[0100] The dynamometer motor 3 is located above the lifting platform 1. The rotor of the dynamometer motor 3 is connected to the roller assembly 2. It receives instructions from the control module, changes the torque, and simulates road conditions.

[0101] The control module weights and fuses the test bench wear deviation and the vehicle stress deviation to obtain a comprehensive deviation signal. Specifically, the weight of the vehicle stress deviation is greater than the weight of the test bench wear deviation.

[0102] The sum of the weights of the vehicle stress deviation and the bench wear deviation equals 1.

[0103] This invention does not treat errors in a general way, but decomposes them into vehicle force deviation and test bench wear deviation. By judging the former, slope correction is triggered, eliminating systematic steady-state errors at their source; by fusing the comprehensive deviations to correct torque, error compensation becomes more accurate and efficient, greatly improving the steady-state level of the control system.

[0104] This invention combines continuous deviation monitoring with batch adjustments, so that slope simulation is no longer a simple signal simulation, but based on real attitude changes.

[0105] Furthermore, the road resistance and gradient information generated by this invention can be used for subsequent vehicle testing, providing a reliable and efficient road environment for the test bench and reducing the risks of road surface testing.

Claims

1. A road environment simulation control method for a new energy vehicle test bench, characterized in that, include: S1. Obtain the theoretical total road resistance and predicted comprehensive friction loss of the target road environment, and add the two together to obtain the initial torque of the test bench dynamometer motor. The specific method for predicting comprehensive friction loss is as follows: obtain the speed change curve of the roller assembly during free deceleration at the initial speed, calculate the internal friction overcome in this process, fit the functional relationship between internal friction and speed and the center distance of the roller assembly, and obtain the internal friction loss. The method of controlling variables is used to obtain the slip friction under each condition, including tire pressure, vehicle axle load, mounting angle and vehicle speed. The slip ratio is calculated based on the wheel speed, the dynamic rolling radius of the tire, the speed of the roller assembly and the radius of the roller assembly. The slip friction loss is obtained by considering the slip friction ratio, mounting angle and vehicle speed. The internal friction loss and the sliding friction loss are added together to obtain the predicted comprehensive friction loss; Obtain vehicle driving force; S2. Based on the longitudinal mechanical model of the vehicle, obtain the actual road resistance, subtract the vehicle driving force, and obtain the vehicle force deviation. Determine whether the slope correction condition is met. If it is met, divide the vehicle force deviation by the product of the vehicle weight and the cosine value of the existing slope angle to obtain the slope angle correction amount. Add it to the existing slope angle to obtain the target slope. Based on the target slope, obtain the height difference of the target roller group on the test bench. Control the lifting platform to make the height difference of the test bench roller group reach the height difference of the target roller group. The actual comprehensive friction loss is obtained, and the test bench loss deviation is obtained by subtracting the predicted comprehensive friction loss from the actual comprehensive friction loss. The test bench loss deviation and the vehicle force deviation are weighted and fused to obtain the comprehensive deviation signal. When the comprehensive deviation signal is greater than or equal to the first error, the torque correction amount is obtained based on the comprehensive deviation signal. The initial torque and the torque correction amount are added together to obtain the target torque. The output of the test bench dynamometer motor is controlled to reach the target torque.

2. The road environment simulation control method for a new energy vehicle test bench according to claim 1, characterized in that, The slope correction condition is that the following conditions must be met simultaneously: Vehicle speed fluctuation < vehicle speed threshold, acceleration < acceleration threshold, vehicle force deviation at consecutive times is greater than vehicle force deviation threshold, and the time interval between two consecutive slope correction operations is greater than the interval threshold.

3. The road environment simulation control method for a new energy vehicle test bench according to claim 1, characterized in that, In S2, the height difference of the target roller group on the test bench is obtained based on the target slope. The specific operation is as follows: Based on the mechanical structure hard limit, a mechanical upper limit is set; based on the current vehicle speed, a dynamic amplitude that is inversely proportional to the vehicle speed is set; based on the product of the existing slope angle change rate threshold and the time interval between adjacent batches, an interval amplitude threshold is set. The minimum value among the mechanical upper limit, dynamic amplitude, and interval amplitude threshold is selected as the maximum value for a single height difference adjustment.

4. The road environment simulation control method for a new energy vehicle test bench according to claim 1, characterized in that, In S2, the torque correction amount is obtained based on the comprehensive deviation signal. The specific operation is as follows: ， in, This is the torque correction amount. , , They are the first coefficient, the second coefficient, and the third coefficient, respectively. , , These are the comprehensive deviation signal at the current time, the comprehensive deviation signal at the previous time, and the comprehensive deviation signal at the time before that, respectively.

5. The road environment simulation control method for a new energy vehicle test bench according to claim 1, characterized in that, In S2, the test bench wear deviation and vehicle stress deviation are weighted and fused to obtain a comprehensive deviation signal. Specifically, the weight of the vehicle stress deviation is greater than the weight of the test bench wear deviation.

6. The road environment simulation control method for a new energy vehicle test bench according to claim 5, characterized in that, The sum of the weights of the vehicle stress deviation and the bench wear deviation equals 1.

7. A road environment simulation control system for a new energy vehicle test bench, used to implement the road environment simulation control method for a new energy vehicle test bench as described in any one of claims 1-6, characterized in that, include: The control module obtains the theoretical total road resistance and predicted comprehensive friction loss of the target road environment, and adds the two together to obtain the initial torque of the test bench dynamometer motor. The specific method for predicting comprehensive friction loss is as follows: obtain the speed change curve of the roller assembly during free deceleration at the initial speed, calculate the internal friction overcome in this process, fit the functional relationship between internal friction and speed and the center distance of the roller assembly, and obtain the internal friction loss. The method of controlling variables is used to obtain the slip friction under each condition, including tire pressure, vehicle axle load, mounting angle and vehicle speed. The slip ratio is calculated based on the wheel speed, the dynamic rolling radius of the tire, the speed of the roller assembly and the radius of the roller assembly. The slip friction loss is obtained by considering the slip friction ratio, mounting angle and vehicle speed. The internal friction loss and the sliding friction loss are added together to obtain the predicted comprehensive friction loss; Obtain vehicle driving force; Based on the longitudinal mechanical model of the vehicle, the actual road resistance is obtained, the vehicle driving force is subtracted, and the vehicle force deviation is obtained. It is then determined whether the slope correction condition is met. If it is met, the vehicle force deviation is divided by the product of the vehicle weight and the cosine value of the existing slope angle to obtain the slope angle correction amount. This correction amount is then added to the existing slope angle to obtain the target slope. Based on the target slope, the height difference of the target roller group on the test bench is obtained. The lifting platform is then controlled to make the height difference of the roller group on the test bench reach the height difference of the target roller group. The actual comprehensive friction loss is obtained, and the predicted comprehensive friction loss is subtracted from the actual comprehensive friction loss to obtain the test bench loss deviation. The test bench loss deviation and the vehicle force deviation are weighted and fused to obtain the comprehensive deviation signal. When the comprehensive deviation signal is greater than or equal to the first error, the torque correction amount is obtained based on the comprehensive deviation signal. The initial torque and the torque correction amount are summed to obtain the target torque. The output of the test bench dynamometer motor is controlled to reach the target torque. The lifting platform is driven by a hydraulic cylinder to ensure the vertical lifting of the roller assembly and to adjust the height difference by receiving instructions from the control module. The roller assembly is located above the lifting platform, and the shaft of the roller assembly is rigidly connected to the dynamometer motor via a coupling. The dynamometer motor is located above the lifting platform. The rotor of the dynamometer motor is connected to the roller assembly. It receives instructions from the control module, changes the torque, and simulates road conditions.

8. The road environment simulation control system for a new energy vehicle test bench according to claim 7, characterized in that, The control module weights and fuses the test bench wear deviation and the vehicle stress deviation to obtain a comprehensive deviation signal. Specifically, the weight of the vehicle stress deviation is greater than the weight of the test bench wear deviation.

9. The road environment simulation control system for a new energy vehicle test bench according to claim 8, characterized in that, The sum of the weights of the vehicle stress deviation and the bench wear deviation equals 1.

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