A slope estimation method, system and vehicle

Abstract

The embodiment of the present application provides a slope estimation method, system and vehicle, the method comprises the following steps: firstly, a first slope estimation value is estimated based on a vehicle dynamics formula, and a second slope estimation value is obtained based on sensor measurement; then, a confidence factor is introduced based on the first slope estimation value and the second slope estimation value, the confidence factor is used to increase the credibility of the slope estimation value, that is, the accuracy of the slope estimation value is increased; then, a comprehensive slope value of the current working condition of the vehicle is obtained based on the accurate slope estimation value; the comprehensive slope value is passivated to prevent the frequent jump of the control state caused by the fluctuation of the slope value; finally, the torque is accurately corrected according to the passivated comprehensive slope value, so that the purpose of accurately controlling the vehicle is achieved, thereby reducing the energy consumption and improving the driving experience of the driver.

Description

Technical Field

[0001] This application relates to the field of new energy vehicles, and in particular to a slope estimation method, system, and vehicle. Background Technology

[0002] With strong support from the government, vehicle control has developed a relatively mature R&D system. In the R&D process of new energy vehicles, refined vehicle control plays a very important role in reducing vehicle energy consumption and improving driving comfort.

[0003] Current vehicle drive torque control strategies obtain the target torque by looking up the accelerator pedal and vehicle speed in different driving modes, and then adjust the target torque based on the current vehicle weight. This torque control strategy is suitable for flat road conditions with little gradient change. However, on road conditions with significant gradient change, the driving experience is poor and the vehicle's energy consumption is high. In addition, the method of estimating the gradient based on the dynamic equation results in a large variation in gradient, which is not conducive to precise torque control. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a slope estimation method, system, and vehicle, which can effectively improve the accuracy of slope estimation, facilitate precise torque correction, achieve refined vehicle control, and enhance driving comfort.

[0005] A first aspect of the present invention provides a slope estimation method, comprising:

[0006] Based on the vehicle dynamics formula, obtain the estimated first slope of the road surface where the vehicle is currently traveling;

[0007] The second slope estimate of the road surface on which the vehicle is currently traveling is obtained using a slope sensor;

[0008] Based on the current operating conditions of the vehicle, a first slope confidence factor based on the vehicle dynamics formula and a second slope confidence factor based on sensor measurements are determined;

[0009] The comprehensive slope value of the road surface on which the vehicle is currently traveling is determined based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor.

[0010] Optionally, obtaining the first slope estimate of the road surface where the vehicle is currently traveling based on the vehicle dynamics formula includes:

[0011] Based on the vehicle dynamics formula, a rough estimate of the first slope of the road surface on which the vehicle is currently traveling is determined;

[0012] The first slope estimate is determined by correcting the rough estimate using the least squares method.

[0013] Optionally, determining a first slope confidence factor based on a vehicle dynamics formula and a second slope confidence factor based on sensor measurements, based on the vehicle's current operating condition, includes:

[0014] Determine the first confidence factor increment for n calculation cycles, and sum the first confidence factor increments for the n calculation cycles to obtain the first slope confidence factor for the current calculation cycle;

[0015] Determine the second confidence factor increments for n calculation cycles, and sum the second confidence factor increments for the n calculation cycles to obtain the second slope confidence factor for the current calculation cycle;

[0016] The current calculation cycle is the nth calculation cycle.

[0017] Optionally, determining the first confidence factor increment over n calculation periods and determining the second confidence factor increment over n calculation periods include:

[0018] Based on the analysis of the actual vehicle test data, the first proportional coefficient and the second proportional coefficient, the first inflection point coefficient and the second inflection point coefficient are determined.

[0019] The confidence factor increment for each calculation cycle is assumed to have a linear relationship with the acceleration. Based on this linear relationship, the first confidence factor increment and the second confidence factor increment are determined. The linear relationship is shown in the following formula:

[0020]

[0021]

[0022] Where β s The first proportionality coefficient, β e The second proportionality coefficient, m s The coefficient of the first inflection point, m e The coefficient of the second inflection point, a n For the acceleration in the nth calculation cycle, For the increment of the first confidence factor in the nth calculation period, The second confidence factor increment is the value of the second confidence factor in the nth calculation period, where n is the calculation period.

[0023] Optionally, determining the first slope confidence factor based on the vehicle dynamics formula based on the vehicle's current operating conditions includes:

[0024] The first confidence factor is incremented and a value is assigned to determine the first slope confidence factor;

[0025] When the increment of the first confidence factor is greater than or equal to the upper threshold value H, the first slope confidence factor is the upper threshold value H;

[0026] When the increment of the first confidence factor is less than or equal to 0, the first slope confidence factor is 0;

[0027] When the increment of the first confidence factor is greater than 0 and less than the upper limit value H, the first slope confidence factor is the sum of the increments of the first confidence factor accumulated over the n calculation cycles.

[0028] Optionally, determining the second slope confidence factor based on sensor measurements, based on the vehicle's current operating condition, includes:

[0029] The second confidence factor is incremented and a value is assigned to determine the second slope confidence factor;

[0030] When the increment of the second confidence factor is greater than or equal to the upper threshold value H, the second slope confidence factor is the upper threshold value H;

[0031] When the increment of the second confidence factor is less than or equal to 0, the second slope confidence factor is 0;

[0032] When the increment of the second confidence factor is greater than 0 and less than the upper limit value H of the threshold, the second slope confidence factor is the sum of the increments of the second confidence factor accumulated over the n calculation cycles.

[0033] Optionally, determining the comprehensive slope value of the road surface where the vehicle is currently traveling based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor includes:

[0034] The first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor are processed using the following formula to determine the comprehensive slope value of the road surface where the vehicle is currently traveling:

[0035]

[0036] Where i is the comprehensive slope value in the nth calculation cycle, The first slope confidence factor for the nth calculation period. This is the estimated slope value for the nth calculation cycle. The second slope confidence factor for the nth calculation period. H is the second slope estimate for the nth calculation cycle, and H is the upper limit of the threshold.

[0037] Optionally, after determining the comprehensive gradient value of the road surface where the vehicle is currently traveling, the process includes:

[0038] The overall slope value is then subjected to passivation processing;

[0039] The torque is corrected based on the overall slope value after passivation treatment;

[0040] The vehicle is driven according to the corrected torque.

[0041] A second aspect of the present invention provides a slope estimation system, comprising:

[0042] The acquisition module is used to obtain the slope estimate value;

[0043] The determination module is used to determine a first slope confidence factor based on vehicle dynamics formulas and a second slope confidence factor based on sensor measurements, based on the current operating conditions of the vehicle.

[0044] The calculation module is used to determine the comprehensive slope value of the road surface where the vehicle is currently traveling based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor.

[0045] Optionally, the acquisition module includes:

[0046] The first acquisition submodule is used to determine a rough estimate of the first slope based on the vehicle dynamics formula.

[0047] The first correction submodule is used to correct the first rough estimate of the slope using the least squares method to determine the first estimate of the slope.

[0048] The second acquisition submodule is used to acquire a second slope estimate value through a slope sensor.

[0049] Optionally, the determining module includes:

[0050] The first determination submodule is used to determine the first confidence factor increment over n calculation cycles;

[0051] The second determination submodule is used to determine the second confidence factor increment over n calculation cycles;

[0052] The third determining submodule is used to assign incremental values ​​to the first confidence factor and determine the first slope confidence factor;

[0053] The fourth determination submodule is used to assign incremental values ​​to the second confidence factor and determine the second slope confidence factor.

[0054] Optionally, the computing module includes:

[0055] The first calculation submodule is used to process the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor using the following formula to determine the comprehensive slope value:

[0056]

[0057] Where i is the comprehensive slope value in the nth calculation cycle, The first slope confidence factor for the nth calculation period. This is the estimated slope value for the nth calculation cycle. The second slope confidence factor for the nth calculation period. H is the second slope estimate for the nth calculation cycle, and H is the upper limit of the threshold.

[0058] Optionally, the acquisition module further includes:

[0059] The passivation submodule is used to passivate the comprehensive slope value;

[0060] The second correction submodule is used to correct the torque based on the comprehensive slope value after passivation treatment;

[0061] A control submodule is used to control the vehicle's movement according to the corrected torque.

[0062] A third aspect of the present invention provides a vehicle that includes the slope estimation system described above. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is a schematic flowchart of a slope estimation method provided in an embodiment of the present invention;

[0065] Figure 2 This is a schematic flowchart of S100 provided in an embodiment of the present invention;

[0066] Figure 3 This is a schematic diagram of the S300 process provided in an embodiment of the present invention;

[0067] Figure 4 This is a schematic diagram of a process for determining a slope confidence factor provided by an embodiment of the present invention;

[0068] Figure 5 This is a system schematic diagram of a slope estimation method provided in an embodiment of the present invention. Detailed Implementation

[0069] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0070] This invention provides a slope estimation method, referring to... Figure 1 , Figure 1 This is a flowchart illustrating a slope estimation method provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the method includes:

[0071] S100, based on the vehicle dynamics formula, obtain the estimated first slope of the road surface where the vehicle is currently traveling;

[0072] In this embodiment of the invention, the slope is first estimated based on the vehicle dynamics formula to determine a rough estimate of the first slope of the road surface on which the vehicle is currently traveling.

[0073] Then, the first rough estimate of the slope is corrected by the least squares method to determine the first slope estimate.

[0074] S200, using a slope sensor, obtains a second slope estimate of the road surface where the vehicle is currently traveling;

[0075] In this embodiment of the invention, a slope sensor installed at a specific location on the vehicle can be used to measure the angle between the road surface currently being driven by the vehicle and the horizontal plane. The angle is the slope angle of the road surface currently being driven by the vehicle, and the tangent of the slope angle is the slope value of the road surface currently being driven by the vehicle.

[0076] S300, based on the current operating conditions of the vehicle, determine a first slope confidence factor based on the vehicle dynamics formula and a second slope confidence factor based on sensor measurements.

[0077] In this embodiment of the invention, the first slope estimate obtained by the vehicle dynamics formula and the second slope estimate obtained by the sensor are often affected by the actual working conditions of the vehicle. Therefore, the first slope estimate obtained by the vehicle dynamics formula and the second slope estimate obtained by the sensor often differ significantly from the actual situation. In view of this, this embodiment of the invention takes into account the influence of different working conditions on the slope estimate and introduces a confidence factor to increase the reliability of the first slope estimate and the second slope estimate.

[0078] By analyzing a large amount of real-vehicle test data of the current vehicle, the first proportional coefficient and the second proportional coefficient, the first inflection point coefficient and the second inflection point coefficient were determined.

[0079] The proportionality coefficient is a parameter used to characterize how quickly the confidence factor changes with vehicle speed; the inflection point coefficient is used to characterize the inflection point of the increase or decrease of the confidence factor, reflecting the starting point of the change in the direction of the accuracy of the slope estimation value obtained by the above two methods.

[0080] In one feasible embodiment, the entire driving process can be divided into multiple calculation cycles, wherein the multiple calculation cycles can be n calculation cycles. In this embodiment of the invention, the confidence factor increment of each calculation cycle is linearly related to the acceleration, and the linear relationship is shown in the following formula:

[0081]

[0082]

[0083] Where β s The first proportionality coefficient, β e The second proportionality coefficient, m s The coefficient of the first inflection point, m e a is the coefficient of the second inflection point. n The acceleration in the nth calculation cycle. For the increment of the first confidence factor in the nth calculation period, This is the increment of the second confidence factor in the nth calculation period, where n is the calculation period.

[0084] In this embodiment of the invention, after obtaining the acceleration of the nth calculation cycle, the first confidence factor increment and the second confidence factor increment of the nth calculation cycle can be obtained based on the above formulas (3) and (4). The acceleration can be obtained by an acceleration sensor or by any other means. This embodiment of the invention does not limit the method.

[0085] Based on this, the first confidence factor increment for the n calculation cycles can be determined through multiple calculations. The first confidence factor increments for the n calculation cycles are then superimposed to obtain the first slope confidence factor for the current calculation cycle, where the current calculation cycle can be the nth calculation cycle.

[0086] Similarly, the second confidence factor increment for n calculation cycles can be determined through multiple calculations. The second confidence factor increments for the n calculation cycles are then superimposed to obtain the second slope confidence factor for the current calculation cycle, where the current calculation cycle can be the nth calculation cycle.

[0087] S400, based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor, determine the comprehensive slope value of the road surface where the vehicle is currently traveling.

[0088] In this embodiment of the invention, due to the influence of the actual operating conditions of the vehicle, the first slope estimate obtained by the vehicle dynamics formula and the second slope estimate obtained by the sensor measurement have significant differences compared with the actual slope value. In this embodiment, a confidence factor is introduced to increase the reliability of the slope estimate.

[0089] Specifically, the product of the first slope estimate and the first slope confidence factor can be used to obtain a first slope estimate with higher confidence; the product of the second slope estimate and the second slope confidence factor can be used to obtain a second slope estimate with higher confidence.

[0090] After obtaining the first and second slope estimates with relatively high reliability, the comprehensive slope value of the road surface where the vehicle is currently traveling can be determined using the following formula:

[0091]

[0092] Where i is the comprehensive slope value in the nth calculation cycle, The first slope confidence factor for the nth calculation period. This is the estimated slope value for the nth calculation cycle. The second slope confidence factor for the nth calculation period. H is the second slope estimate for the nth calculation cycle, and H is the upper limit of the threshold.

[0093] In this embodiment of the invention, considering that fluctuations in the slope value may cause frequent changes in the control state, it is necessary to passivate the slope value. This can be achieved using the quantizer built into Simulink, with the resolution set to 0.5 degrees, to passivate the overall slope value. It should be noted that the Simulink passivation method used in this invention is only one method well-known in the art, and other passivation methods are not limited herein.

[0094] Then, the torque is corrected based on the comprehensive slope value after passivation treatment, and the vehicle is controlled to drive according to the corrected torque.

[0095] Furthermore, such as Figure 2 As shown, based on the vehicle dynamics formula, the estimated first slope of the road surface where the vehicle is currently traveling is obtained, including:

[0096] S101, A preliminary estimate of the slope is made based on the vehicle dynamics formula, which is shown below:

[0097]

[0098] Wherein: T D Motor output torque, i0; transmission ratio, i j η: gearbox ratio, r: wheel radius, mg: vehicle weight, f: rolling resistance coefficient, C D Air drag coefficient, A: vehicle frontal area, u: vehicle speed, θ: gradient, δ: rotational mass conversion factor. Acceleration.

[0099] In this embodiment, based on actual road conditions, in Formula 1, cosθ≈1 and sinθ≈θ, Formula 1 can be simplified as follows:

[0100]

[0101] Furthermore, in this embodiment of the invention, variables y and b are introduced, and formula (2) is decomposed to obtain the following formula:

[0102]

[0103] The above formula based on the variables y and b can be further transformed into:

[0104]

[0105] Given the vehicle's mass, the driving force of the entire vehicle is calculated based on parameters such as driving torque, transmission ratio, gearbox ratio, tire radius, and transmission efficiency. The air resistance is calculated based on parameters such as air drag coefficient, vehicle frontal area, and vehicle speed. The variable y is obtained by subtracting the longitudinal acceleration resistance and air resistance from the driving force of the entire vehicle.

[0106] Furthermore, the rolling resistance coefficient f can be calculated by obtaining the vehicle's real-time speed u. The formula for calculating the rolling resistance coefficient is as follows:

[0107]

[0108] Furthermore, a rough estimate of the first slope can be obtained according to formula (5).

[0109] S102, the first rough estimate of the slope is corrected by the least squares method to determine the first slope estimate.

[0110] Since the noise of actual signals is generally large, the slope calculated by directly applying formula (2) will have large oscillations. Therefore, it is necessary to use the least squares method to estimate and regress the slope. Since the rough estimate of the first slope obtained based on the vehicle dynamics formula changes in real time with the current working condition of the vehicle, a forgetting factor λ is introduced into the recursive squares method to obtain a criterion formula based on the forgetting factor, which can overcome the phenomenon of data saturation. The criterion formula is as follows:

[0111]

[0112] The larger the forgetting factor λ, the higher the accuracy but the slower the convergence speed; the smaller the forgetting factor λ, the lower the accuracy but the faster the convergence speed. Where 0 < λ ≤ 1.

[0113] Furthermore, by differentiating the criterion function described in formula (7), we obtain the following function:

[0114]

[0115]

[0116]

[0117] in, Let λ be the criterion function, λ be the forgetting factor, and y be the longitudinal driving force of the wheel minus acceleration drag and air resistance. Here, k and i represent the estimated value of the slope function, and k and i represent different times.

[0118] right Assign initial values ​​to P(0) and select A parameter that is 0 or small. P(0) = α2 , where α is a sufficiently large parameter.

[0119] The above formula can be used to estimate the value of variable b at each time point, and further, the estimated value of the first slope of the road surface can be obtained according to formula (5).

[0120] Furthermore, such as Figure 3 As shown, based on the current operating condition of the vehicle, a first slope confidence factor based on the vehicle dynamics formula and a second slope confidence factor based on sensor measurements are determined, including:

[0121] First, it is necessary to analyze a large amount of real-vehicle test data of the current vehicle to determine the first proportional coefficient, the second proportional coefficient, the first inflection point coefficient, and the second inflection point coefficient.

[0122] S301, by establishing a linear relationship between the confidence factor increment and acceleration for each calculation cycle, the first confidence factor increment is determined based on this linear relationship. The linear relationship is shown in the following formula:

[0123] ΔK s = s (am s (11)

[0124] Where β s The first proportionality coefficient, m s Let 'a' be the coefficient at the first inflection point, 'a' be the acceleration, and 'ΔK' be s This is the increment of the first confidence factor.

[0125] The first confidence factor increment of the vehicle in the current calculation period can be determined using the above linear relationship formula (11) and the acceleration of the vehicle in the current calculation period.

[0126] In one feasible embodiment, the entire driving process can be divided into multiple calculation cycles, which can be n calculation cycles, and the current calculation cycle can be the nth calculation cycle.

[0127] In a specific embodiment of the present invention, a calculation cycle can be set to 5 seconds. Therefore, the n calculation cycles can be 5 seconds, 10 seconds, 15 seconds, 20 seconds...(5n) seconds.

[0128] Therefore, the above formula can be transformed into the following formula (3):

[0129] Where β s The first proportionality coefficient, m s The coefficient of the first inflection point, a n The acceleration in the nth calculation cycle, The increment of the first confidence factor is the value in the nth calculation period, where n is the calculation period.

[0130] The first confidence factor increment of the vehicle in the nth calculation cycle can be determined by using the modified formula (3) of the above linear relationship and the acceleration of the vehicle in the nth calculation cycle.

[0131] S302, by establishing a linear relationship between the confidence factor increment and the acceleration in each calculation cycle, the second confidence factor increment is determined based on this linear relationship. The linear relationship is shown in the following formula:

[0132] ΔK e =β e (am e (12)

[0133] Where β e The second proportionality coefficient, m e Here, ΔK is the coefficient at the second inflection point, a is the acceleration, and ΔK is the coefficient at the second inflection point. e This is the increment of the second confidence factor.

[0134] The second confidence factor increment of the vehicle in the current calculation period can be determined using the above linear relationship formula (12) and the acceleration of the vehicle in the current calculation period.

[0135] Similarly, in one feasible embodiment, the entire driving process can be divided into multiple calculation cycles, which can be n calculation cycles, and the current calculation cycle can be the nth calculation cycle. In a specific embodiment of the present invention, each calculation cycle can be set to 5 seconds. Therefore, the n calculation cycles can be 5 seconds, 10 seconds, 15 seconds, 20 seconds...(5n) seconds.

[0136] Therefore, the above formula can be transformed into the following formula (4):

[0137] Where β e The second proportionality coefficient, m e The coefficient of the second inflection point, a n For the acceleration in the nth calculation cycle, This is the increment of the second confidence factor in the nth calculation period, where n is the calculation period.

[0138] The second confidence factor increment of the vehicle in the nth period can be determined by using the modified formula (4) of the above linear relationship and the acceleration of the vehicle in the nth calculation period.

[0139] S303, assign an incremental value to the first confidence factor to determine the first slope confidence factor.

[0140] For specific assignment relationships, please refer to the following: Figure 4 The diagram shows the process for determining the confidence factor.

[0141] When the increment of the first confidence factor is greater than or equal to the upper threshold value H, the first slope confidence factor is the upper threshold value H;

[0142] When the increment of the first confidence factor is less than or equal to 0, the first slope confidence factor is 0;

[0143] When the increment of the first confidence factor is greater than 0 and less than the upper limit value H, the first slope confidence factor is the sum of the increments of the first confidence factor accumulated over the n calculation cycles.

[0144] For example, in a feasible embodiment of the present invention, the upper limit of the threshold can be 100, that is, when the increment of the first confidence factor is greater than or equal to 100, the first slope confidence factor is 100.

[0145] When the increment of the first confidence factor is less than or equal to 0, the first slope confidence factor is 0;

[0146] When the increment of the first confidence factor is between 0 and 100, the first slope confidence factor is the sum of the increments of the first confidence factor accumulated over the n calculation cycles.

[0147] S304, assign an incremental value to the second confidence factor to determine the second slope confidence factor.

[0148] For specific assignment relationships, please refer to the following: Figure 4 The diagram shows the process for determining the confidence factor.

[0149] When the increment of the second confidence factor is greater than or equal to the upper threshold value H, the second slope confidence factor is the upper threshold value H;

[0150] When the increment of the second confidence factor is less than or equal to 0, the second slope confidence factor is 0;

[0151] When the increment of the second confidence factor is greater than 0 and less than the upper limit value H of the threshold, the second slope confidence factor is the sum of the increments of the second confidence factor accumulated over the n calculation cycles.

[0152] Similarly, for example, in a feasible embodiment of the present invention, the upper limit of the threshold can be 100, that is, when the increment of the second confidence factor is greater than or equal to 100, the second slope confidence factor is 100.

[0153] When the increment of the second confidence factor is less than or equal to 0, the second slope confidence factor is 0;

[0154] When the increment of the second confidence factor is between 0 and 100, the second confidence factor is the sum of the increments of the second confidence factor accumulated over the n calculation periods.

[0155] In this embodiment of the invention, in step S400, the comprehensive slope value of the road surface where the vehicle is currently traveling is determined based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor. This specifically includes the following steps:

[0156] S401, in this embodiment of the invention, after determining the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor, the comprehensive slope value of the road surface where the vehicle is currently traveling can be determined. The comprehensive slope value can be calculated according to the following formula:

[0157]

[0158] Where i is the comprehensive slope value in the nth calculation cycle, The first slope confidence factor for the nth calculation period. This is the estimated slope value for the nth calculation cycle. The second slope confidence factor for the nth calculation period. H is the second slope estimate for the nth calculation cycle, and H is the upper limit of the threshold.

[0159] Similarly, in one feasible embodiment of the present invention, the upper limit of the threshold can be set to 100. Therefore, the above formula for calculating the comprehensive slope value can be:

[0160]

[0161] S402, the comprehensive slope value is passivated.

[0162] In this embodiment of the invention, considering that fluctuations in the slope value may cause frequent changes in the control state, it is necessary to passivate the slope value. This can be achieved using the quantizer built into Simulink, with the resolution set to 0.5 degrees, to passivate the overall slope value. It should be noted that the Simulink passivation method used in this invention is only one method well-known in the art, and other passivation methods are not limited herein.

[0163] S403, the torque is corrected based on the overall slope value after passivation treatment.

[0164] In this embodiment of the invention, in order to achieve accurate correction of torque based on the comprehensive slope value after passivation treatment, the comprehensive slope value after passivation treatment is divided into different slope levels.

[0165] When the overall slope value is greater than or equal to G1, the slope level is set to a large uphill slope.

[0166] When the overall slope value is between G2 and G1, the slope grade is set to a small uphill slope, where G2 is less than G1.

[0167] When the overall slope value is greater than or equal to -G2 and less than or equal to G2, the slope grade is set to flat slope.

[0168] When the overall slope value is greater than -G1 and less than -G2, the slope level is set to a slight downhill slope.

[0169] When the overall slope value is less than or equal to -G1, the slope level is set to a steep downhill slope.

[0170] S404, controlling the vehicle's movement according to the corrected torque.

[0171] In a feasible embodiment of the present invention, G1 can be set to 3.4 and G2 to 0.5. Therefore, the above slope grade division can be:

[0172] When the overall slope value is greater than or equal to 3.4, the slope level is set to a steep uphill slope.

[0173] When the overall slope value is between 0.5 and 3.4, the slope level is set to a slight uphill slope.

[0174] When the overall slope value is greater than or equal to -0.5 and less than or equal to 0.5, the slope grade is set to flat slope.

[0175] When the overall slope value is greater than -3.4 and less than -0.5, the slope grade is set to a slight downhill slope.

[0176] When the overall slope value is less than or equal to -3.4, the slope grade is set to a steep downhill slope.

[0177] Then, the torque is precisely adjusted according to different slope levels, which can also avoid frequent torque jumps.

[0178] After the torque is precisely corrected according to different slope levels, the vehicle can be precisely controlled in real time according to the corrected torque.

[0179] By adopting the technical solution of the present invention, a confidence factor can be introduced on the basis of the slope value estimated based on the vehicle dynamics formula and the slope measured by the sensor, thereby increasing the reliability of the slope estimation value, that is, increasing the accuracy of the slope estimation value. This allows the vehicle to accurately adjust the target torque by accurately estimating the slope even under conditions with large slope fluctuations, thereby improving the driving experience and reducing energy consumption.

[0180] This invention also provides a slope estimation system, comprising:

[0181] The acquisition module is used to obtain the slope estimate value;

[0182] The determination module is used to determine a first slope confidence factor based on vehicle dynamics formulas and a second slope confidence factor based on sensor measurements, based on the current operating conditions of the vehicle.

[0183] The calculation module is used to determine the comprehensive slope value of the road surface where the vehicle is currently traveling based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor.

[0184] Optionally, the acquisition module includes:

[0185] The first acquisition submodule is used to determine a rough estimate of the first slope based on the vehicle dynamics formula.

[0186] The first correction submodule is used to correct the first rough estimate of the slope using the least squares method to determine the first estimate of the slope.

[0187] The second acquisition submodule is used to acquire a second slope estimate value through a slope sensor.

[0188] Optionally, the determining module includes:

[0189] The first determination submodule is used to determine the first confidence factor increment over n calculation cycles;

[0190] The second determination submodule is used to determine the second confidence factor increment over n calculation cycles;

[0191] The third determining submodule is used to assign incremental values ​​to the first confidence factor and determine the first slope confidence factor;

[0192] The fourth determination submodule is used to assign incremental values ​​to the second confidence factor and determine the second slope confidence factor.

[0193] Optionally, the computing module includes:

[0194] The first calculation submodule is used to process the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor using the following formula to determine the comprehensive slope value:

[0195]

[0196] Where i is the comprehensive slope value in the nth calculation cycle, The first slope confidence factor for the nth calculation period. This is the estimated slope value for the nth calculation cycle. The second slope confidence factor for the nth calculation period. H is the second slope estimate for the nth calculation cycle, and H is the upper limit of the threshold.

[0197] Optionally, the acquisition module further includes:

[0198] The passivation submodule is used to passivate the comprehensive slope value;

[0199] The second correction submodule is used to correct the torque based on the comprehensive slope value after passivation treatment;

[0200] A control submodule is used to control the vehicle's movement according to the corrected torque.

[0201] This invention also provides a vehicle that includes the slope estimation system described above.

[0202] This invention provides a slope estimation method, system, and vehicle. The method includes: firstly, estimating a first slope estimate based on vehicle dynamics formulas and obtaining a second slope estimate based on sensor measurements; then, introducing a confidence factor based on the first and second slope estimates to increase the reliability of the slope estimates, i.e., increasing their accuracy; then, obtaining a comprehensive slope value for the current operating condition of the vehicle based on the accurate slope estimates; and finally, performing a passivation process on the comprehensive slope value to prevent fluctuations in the slope value from causing frequent changes in the control state; and finally, precisely correcting the torque based on the passivated comprehensive slope value to achieve precise vehicle control, thereby reducing energy consumption and improving the driver's driving experience.

[0203] The above description represents preferred embodiments of the present invention. It should be noted that although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

[0204] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0205] The above provides a detailed description of the slope estimation method, system, and vehicle provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A slope estimation method, characterized in that, The method includes: Based on the vehicle dynamics formula, obtain the estimated first slope of the road surface where the vehicle is currently traveling; The second slope estimate of the road surface on which the vehicle is currently traveling is obtained using a slope sensor; Based on the current operating conditions of the vehicle, a first slope confidence factor based on the vehicle dynamics formula and a second slope confidence factor based on sensor measurements are determined; The determination of a first slope confidence factor based on a vehicle dynamics formula and a second slope confidence factor based on sensor measurements, based on the vehicle's current operating condition, includes: Determine the first confidence factor increment for n calculation cycles, and sum the first confidence factor increments for the n calculation cycles to obtain the first slope confidence factor for the current calculation cycle; Determine the second confidence factor increments for n calculation cycles, and sum the second confidence factor increments for the n calculation cycles to obtain the second slope confidence factor for the current calculation cycle; The current calculation cycle is the nth calculation cycle; Based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor, the comprehensive slope value of the road surface where the vehicle is currently traveling is determined; The step of determining the comprehensive slope value of the road surface where the vehicle is currently traveling based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor includes: The first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor are processed using the following formula to determine the comprehensive slope value of the road surface where the vehicle is currently traveling: Where i is the comprehensive slope value in the nth calculation cycle, The first slope confidence factor for the nth calculation period. This is the estimated slope value for the nth calculation cycle. The second slope confidence factor for the nth calculation period. This is the estimated second slope value for the nth calculation cycle. This is the upper limit of the threshold.

2. The slope estimation method according to claim 1, characterized in that, The step of obtaining the estimated first slope of the road surface where the vehicle is currently traveling based on the vehicle dynamics formula includes: Based on the vehicle dynamics formula, a rough estimate of the first slope of the road surface on which the vehicle is currently traveling is determined; The first slope estimate is determined by correcting the rough estimate using the least squares method.

3. The slope estimation method according to claim 1, characterized in that, The determination of the first confidence factor increment over n calculation periods and the determination of the second confidence factor increment over n calculation periods include: Based on the analysis of the actual vehicle test data, the first proportional coefficient and the second proportional coefficient, the first inflection point coefficient and the second inflection point coefficient are determined. The confidence factor increment for each calculation cycle is assumed to have a linear relationship with the acceleration. Based on this linear relationship, the first confidence factor increment and the second confidence factor increment are determined. The linear relationship is shown in the following formula: in The first proportionality coefficient, For the second proportionality coefficient, The coefficient of the first inflection point, The coefficient of the second inflection point, For the acceleration in the nth calculation cycle, For the increment of the first confidence factor in the nth calculation period, The increment of the second confidence factor in the nth calculation period, The calculation period is [number].

4. The slope estimation method according to claim 1, characterized in that, The determination of the first slope confidence factor based on the vehicle dynamics formula, based on the vehicle's current operating condition, includes: The first confidence factor is incremented and a value is assigned to determine the first slope confidence factor; When the increment of the first confidence factor is greater than or equal to the upper threshold value H, the first slope confidence factor is the upper threshold value H; When the increment of the first confidence factor is less than or equal to 0, the first slope confidence factor is 0; When the increment of the first confidence factor is greater than 0 and less than the upper limit value H, the first slope confidence factor is the sum of the increments of the first confidence factor accumulated over the n calculation cycles.

5. The slope estimation method according to claim 1, characterized in that, The determination of the second slope confidence factor based on sensor measurements, based on the vehicle's current operating condition, includes: The second confidence factor is incremented and a value is assigned to determine the second slope confidence factor; When the increment of the second confidence factor is greater than or equal to the upper threshold value H, the second slope confidence factor is the upper threshold value H; When the increment of the second confidence factor is less than or equal to 0, the second slope confidence factor is 0; When the increment of the second confidence factor is greater than 0 and less than the upper limit value H of the threshold, the second slope confidence factor is the sum of the increments of the second confidence factor accumulated over the n calculation cycles.

6. The slope estimation method according to claim 1, characterized in that, After determining the overall gradient value of the road surface where the vehicle is currently traveling, the process includes: The overall slope value is then subjected to passivation processing; The torque is corrected based on the overall slope value after passivation treatment; The vehicle is driven according to the corrected torque.

7. A slope estimation system, characterized in that, The system includes: The acquisition module is used to obtain the slope estimate value; The acquisition module includes: The first acquisition submodule is used to determine a rough estimate of the first slope based on the vehicle dynamics formula; The first correction submodule is used to correct the first rough estimate of the slope using the least squares method to determine the first slope estimate. The second acquisition submodule is used to acquire a second slope estimate value through a slope sensor; The determination module is used to determine a first slope confidence factor based on vehicle dynamics formulas and a second slope confidence factor based on sensor measurements, based on the current operating conditions of the vehicle. The determining module includes: The first determination submodule is used to determine the first confidence factor increment over n calculation cycles; The second determination submodule is used to determine the second confidence factor increment over n calculation cycles; The third determining submodule is used to assign incremental values ​​to the first confidence factor and determine the first slope confidence factor; The fourth determination submodule is used to assign incremental values ​​to the second confidence factor and determine the second slope confidence factor; The calculation module is used to determine the comprehensive slope value of the road surface where the vehicle is currently traveling based on the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor. The computing module includes: The first calculation submodule is used to process the first slope estimate, the second slope estimate, the first slope confidence factor, and the second slope confidence factor using the following formula to determine the comprehensive slope value: Where i is the comprehensive slope value in the nth calculation cycle, The first slope confidence factor for the nth calculation period. This is the estimated slope value for the nth calculation cycle. The second slope confidence factor for the nth calculation period. This is the estimated second slope value for the nth calculation cycle. This is the upper limit of the threshold.

8. The slope estimation system according to claim 7, characterized in that, The acquisition module further includes: The passivation submodule is used to passivate the comprehensive slope value; The second correction submodule is used to correct the torque based on the comprehensive slope value after passivation treatment; A control submodule is used to control the vehicle's movement according to the corrected torque.

9. A vehicle, characterized in that, The vehicle includes the slope estimation system as described in any one of claims 7 to 8.

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