A method for building a braking condition of a light vehicle

Abstract

The application provides a light vehicle braking condition construction method, comprising the following steps: vehicle single trip segment duration distribution calculation; single trip segment library construction; short trip library construction; short trip library segment screening; short trip library feature parameter calculation; segment number calculation; alternative condition library construction; typical condition set construction; optimal braking condition selection; and condition steady state. The light vehicle braking condition construction method is rationally designed, collects vehicle speed and brake pedal opening degree data in actual vehicle driving process, constructs a representative braking condition set by a short trip method, and selects an optimal braking condition by using a chi-square test. The condition is used as a test condition, and more actual road conditions of automobile non-tail gas emissions can be measured by a laboratory drum test. Meanwhile, the steady state condition can help enterprises to realize part-level non-tail gas emission testing on a test bench.

Description

Technical Field

[0001] This invention belongs to the field of transportation, and in particular relates to a method for constructing braking conditions for light vehicles. Background Technology

[0002] When assessing particulate matter emissions from motor vehicles, the focus is primarily on the quantity of particulate matter in vehicle exhaust. Current national standards only specify the numerical value of particulate matter in exhaust emissions. However, during vehicle operation, particulate matter emissions originate not only from exhaust but also from brake discs, tires, crankcases, and road surfaces. Furthermore, with the increasing number of electric vehicles, the proportion of non-exhaust-source particulate matter emissions will rise. Non-exhaust-source emissions are closely related to vehicle braking. To more accurately measure non-exhaust-source particulate matter emissions during braking, Europe has developed braking conditions based on the WLTC test cycle database to represent real-world European road conditions for non-exhaust-source emission testing. Currently, my country lacks a unified testing curve for non-exhaust-source emissions. Therefore, developing a braking condition that conforms to my country's actual road conditions is crucial for further reducing vehicle particulate matter emissions, improving air quality, and winning the "Blue Sky Protection Campaign." Summary of the Invention

[0003] In view of this, the present invention aims to propose a method for constructing braking conditions for light vehicles, which constructs a condition curve that can truly reflect the actual braking scenarios of light vehicles on Chinese roads by collecting two key parameters, namely vehicle speed and brake pedal opening, during the actual road driving process of the vehicle, and provides a unified condition curve for non-exhaust particulate matter emission testing of light vehicles in my country.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A method for constructing braking conditions for light vehicles includes the following steps:

[0006] S1: Based on the original vehicle data, calculate the duration distribution of a single trip segment, and calculate the duration T1 to T1 corresponding to the typical quantile values. 10 ;

[0007] S2: T1 to T1 respectively 10 As boundary conditions, the vehicle single trip segment data in step S1 are divided into single trip segment libraries J1 to J2. 10 middle;

[0008] S3; Using the short-distance method, the single-trip segment library J1~J 10 The single trip segment of a vehicle is divided into J1 to J2. 10 Each short-stroke segment consists of an idle segment and an adjacent motion segment, based on J1 to J2.10 Constructing short trip library K1 ~ K 10 ;

[0009] S4: Calculate the length of each idle segment and the highest speed, maximum acceleration, maximum deceleration and motion duration of each motion segment in short trip library K1 ~ K 10 , and clean the idle and motion segments obtained in step S3, deleting segments that do not meet the screening rules (when deleting a motion segment or an idle segment, the corresponding idle segment or motion segment is also deleted); number each motion segment in short trip library K1 ~ K 10 , the first segment in K2 is numbered as the last segment in K1 plus 1, and so on;

[0010] S5: Calculate the characteristic parameters of each short trip segment in short trip library K1 ~ K 10 , including braking parameters and duration parameters, and determine the braking parameters according to the braking rules;

[0011] S6: Based on short trip library K1 ~ K 10 in step S5, divide the short trips in K1 ~ K 10 into low, medium and high speed intervals according to the highest speed, and calculate the number of low speed segments, medium speed segments, high speed segments and idle segments required in each short trip library in combination with T1 ~ T 10 ;

[0012] S7: According to the calculation results of step S5, select motion segments and corresponding idle segments in K1 ~ K 10 whose characteristic parameters have an error within 15% of the short trip library to which they belong, to form working condition library L1 ~ L 10 ;

[0013] S8: According to the results of step S6, randomly select corresponding number of motion segments in working condition library L1 ~ L 10 for combination, and insert corresponding duration of idle segments between adjacent two motion segments, to obtain typical working condition set C1 ~ C 10 of working condition library L1 ~ L 10 ;

[0014] S9: Perform chi-square test on the average speed and average deceleration of the typical working conditions in typical working condition set C1 ~ C 10 , and select the working condition with the optimal average chi-square value as the optimal working condition of the set, and sequentially connect the optimal working conditions in typical working condition set C1 ~ C 10 to obtain the braking working condition curve;

[0015] S10: Perform steady-state processing on the working condition curve obtained in step S9.

[0016] Further, in the step S2, the vehicle single trip segment data in the step S1 is respectively divided into single trip segment library J1-J9. 10 In the step S2, the following steps are included:

[0017] S21, judging whether the vehicle single trip time t is in the range of T i ≤t<T i+1 , where i=1, 2, …, 9, if yes, the vehicle trip segment is divided into single trip segment library J i+1 , if no, go to step S22;

[0018] S22, judging whether the vehicle single trip time t is in the range of t≥T 10 , if yes, the vehicle trip segment is discarded, if no, go to step S23;

[0019] S23, judging whether the vehicle single trip time t is in the range of t<T1, if yes, the vehicle trip segment is divided into single trip segment library J1.

[0020] Further, in the step S5, the brake type parameters include average deceleration, brake time, brake distance, brake initial speed, brake times per kilometer; the time type parameters include movement time, idling time, total time.

[0021] Further, in the step S6, the low speed, medium speed, high speed segment intervals are divided according to the following rules:

[0022] S61a, judging whether the highest speed of the movement segment is less than or equal to 60km / h, if yes, the movement segment is divided in the low speed interval, the movement segment is low speed movement segment, if no, go to step S62a;

[0023] S62a, judging whether the highest speed of the movement segment is greater than 60km / h, less than or equal to 80km / h, if yes, the movement segment is divided in the medium speed interval, the movement segment is medium speed movement segment, if no, go to step S63a;

[0024] S63a, judging whether the highest speed of the movement segment is greater than 80km / h, if yes, the movement segment is divided in the high speed interval, the movement segment is high speed movement segment.

[0025] Further, in the step S6, the number of low speed segments, medium speed segments, high speed segments and idling segments required in each short trip library is calculated, including the following steps:

[0026] S61b, calculate the average duration of low-speed segments, the average duration of medium-speed segments, and the average duration of high-speed segments in each short-trip library, respectively;

[0027] S62b, obtain the number of low-speed segments by the low-speed segment number calculation formula, obtain the number of medium-speed segments by the medium-speed segment number calculation formula, and obtain the number of high-speed segments by the high-speed segment number calculation formula;

[0028] S63b, obtain the number of idle-speed segments by the idle-speed segment number calculation formula.

[0029] Further, the low-speed segment number calculation formula is: low-speed segment number n1=T i * low-speed segment duration proportion / low-speed segment average duration.

[0030] Further, the medium-speed segment number calculation formula is: medium-speed segment number n2=T i * medium-speed segment duration proportion / medium-speed segment average duration.

[0031] Further, the high-speed segment number calculation formula is: high-speed segment number n3=T i * high-speed segment duration proportion / high-speed segment average duration.

[0032] Further, the idle-speed segment number calculation formula is: n4=n1+n2+n3

[0033] Wherein, n4 is the number of idle-speed segments, n1 is the number of low-speed segments, n2 is the number of medium-speed segments, and n3 is the number of high-speed segments.

[0034] Further, the steady-state processing in step S10 includes the following steps:

[0035] S101, according to the brake initial speed, brake duration and average brake deceleration of the corresponding short-trip segment in step S5, the deceleration segment is changed into a uniform deceleration process, and the initial speed of the deceleration segment is recorded as v1, and the corresponding time is t2;

[0036] S102, find the time when the speed in the acceleration segment reaches v1, recorded as t1;

[0037] S103, replace the uniform speed segment between t1 and t2, and the vehicle speed is v1;

[0038] S104, calculate the average vehicle speed of each acceleration segment;

[0039] S105, take the average speed of 5 km / h and the acceleration of 0.1 m / s 2 as the interval, calculate K1~K 10 The acceleration cumulative distribution of all motion segments at different average speeds;

[0040] S106. Select the 50th percentile value of the cumulative distribution of acceleration at the corresponding average vehicle speed in step S105 as the acceleration value of the acceleration segment, and transform the acceleration segment into a uniform acceleration process.

[0041] Compared with existing technologies, the method for constructing braking conditions for light vehicles described in this invention has the following advantages:

[0042] (1) The braking condition construction method for light vehicles described in this invention is reasonably designed. By collecting data such as vehicle speed and brake pedal opening during actual vehicle operation, a braking condition that conforms to the actual road conditions in my country is constructed. Using this condition as a test condition, a vehicle non-exhaust particulate matter emission that is more consistent with actual road conditions can be measured through laboratory drum tests, providing a theoretical basis for further reducing overall vehicle particulate matter emissions.

[0043] (2) After the operating conditions are stabilized, the non-exhaust gas particulate matter emission test at the component level can be carried out on the laboratory bench, which can effectively reduce the enterprise's R&D costs. Attached Figure Description

[0044] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0045] Figure 1 This is a flowchart illustrating the overall operating condition construction process as described in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram illustrating the travel time distribution according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the working condition database as described in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the short-stroke method described in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the short-stroke library according to an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram illustrating a typical operating condition (C1) as described in an embodiment of the present invention.

[0051] Figure 7 This is a schematic diagram comparing segments before and after stabilization according to an embodiment of the present invention. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0053] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] Definitions:

[0055] Chi-square test: The chi-square test is a widely used hypothesis testing method. Its applications in statistical inference of categorical data include chi-square tests comparing two rates or two proportions; chi-square tests comparing multiple rates or multiple proportions; and correlation analysis of categorical data.

[0056] Short-stroke method: Short stroke refers to the cycle of a car between two adjacent parking points. It can be defined as starting from one idling start point and ending at another idling start point. A complete short stroke consists of an idling segment and a motion segment.

[0057] like Figures 1 to 7 As shown, a method for constructing braking conditions for a light vehicle includes the following steps:

[0058] Step 1: Based on the vehicle's original data (actual road driving data), calculate the cumulative distribution of the duration of a single trip segment (the journey from point A to point B), and calculate the durations T1 to T1 corresponding to the typical quantiles. 10 Specifically, T1 to T 10 The durations corresponding to the 5%, 15%, 25%, 35%, 45%, 55%, 65%, 75%, 85%, and 95% percentiles, respectively;

[0059] Step 2: Using T1 to T1 respectively 10 As boundary conditions, the data for a single vehicle trip are divided into operating condition databases J1 to J2. 10 In this context, the specific division method is as follows: if the duration of a single trip for a vehicle is T... i ≤t <T i+1 Then this trip will be assigned to the operating condition database J. i In the given information, i = 1, 2, ..., 9, if t ≥ T 10 This trip will then be classified as J. 10 middle.

[0060] Step 3: Use the short-stroke method to convert the operating condition database J1 to J2. 10 A single trip segment is divided into short-distance segments (each short-distance segment consists of an idling segment and an adjacent motion segment), and a short-distance library K1 to K is constructed. 10 .

[0061] Step 4: Calculate K1 to K1 respectively. 10The idle and motion segments obtained in step 3 are cleaned up, and segments that do not meet the conditions are deleted. When deleting an idle segment or a motion segment, the corresponding motion or idle segment is also deleted. K1~K 10 Each motion segment is numbered, and the number of the first segment in K2 is one more than the number of the last segment in K1, and the same applies to the rest.

[0062] Step 5: Calculate short trip library K1~K 10 and two categories of feature parameters for each short trip segment, a total of 8. The brake parameters include average deceleration, braking duration, braking distance, braking initial speed, and braking frequency per kilometer. The duration parameters include motion duration, idle duration, and total duration.

[0063] Step 6: Calculate short trip library K1~K 10 The proportion of low-speed, medium-speed, high-speed motion segments, and idle segment duration. Combine T1~T 10 Calculate the number of low-speed, medium-speed, high-speed, and idle segments required in each short trip library. For example, the number of low-speed segments n1 = T1 * low-speed segment duration proportion / low-speed segment average duration, the number of medium-speed segments n2 = T1 * medium-speed segment duration proportion / medium-speed segment average duration, the number of high-speed segments n3 = T1 * high-speed segment duration proportion / high-speed segment average duration, and the number of idle segments n4 = n1 + n2 + n3. The idle segment duration = T1 * idle segment duration proportion / n4. The above calculation results need to be rounded.

[0064] Step 7: According to the calculation results of step 5, select motion segments and corresponding idle segments in K1~K 10 with feature parameters and their corresponding working condition library error within 15%, and form working condition library L1~L 10 ;

[0065] Step 8: According to the results of step 6, randomly select corresponding number of motion segments in L1~L 10 , and insert corresponding duration idle segments between adjacent two motion segments, to obtain typical working condition set C1~C 10 ; 10

[0066] Step 9: Perform chi-square test on the average speed and average brake deceleration of the typical working conditions in C1~C 10 , and select the working condition with the optimal average chi-square value as the optimal working condition of the set. Connect the optimal working conditions in C1~C 10 head to tail to obtain a brake working condition curve that can represent the actual road conditions in China.​

[0067] Step 10: To ensure the braking performance curve is operable on the laboratory drum, the performance curve obtained in Step 9 needs to be stabilized. The specific method is as follows:

[0068] 1) Based on the initial braking velocity, braking duration, and average braking deceleration of the corresponding segment in step 5, the deceleration segment is transformed into a uniform deceleration process. The initial velocity of the deceleration segment is denoted as v1, and the corresponding time is t2.

[0069] 2) Find the moment when the speed reaches v1 in the acceleration segment, and denote it as t1;

[0070] 3) The section between t1 and t2 is replaced by a constant speed segment with a vehicle speed of v1;

[0071] 4) Calculate the average vehicle speed for each acceleration segment;

[0072] 5) At an average speed of 5 km / h and an acceleration of 0.1 m / s² 2 Calculate K1 to K as intervals. 10 The cumulative distribution of acceleration at different average velocities across all motion segments;

[0073] 6) Select the 50th percentile of the cumulative distribution of acceleration at the corresponding average vehicle speed in step 5 as the acceleration value of the acceleration segment, and transform the acceleration segment into a uniform acceleration process.

[0074] Example 1

[0075] Step 1: First, use the raw data to calculate the distribution of user single trip duration, such as... Figure 2 As shown in the figure. In this embodiment, the duration of a single trip refers to the time it takes for a user to travel from point A to destination point B.

[0076] Based on the cumulative distribution frequency of travel duration, calculate the travel durations T1 to T2 corresponding to the percentages of travel duration at 5%, 15%, 25%, 35%, 45%, 55%, 65%, 75%, 85%, and 95%. 10 like Figure 2 As shown, in this invention, T1 to T 10 The values ​​are 408s, 619s, 892s, 1217s, 1579s, 1969s, 2421s, 3034s, 4065s, and 6616s, respectively.

[0077] Step 2: Using T1 to T1 respectively 10 To determine the target duration, the single trip segments from step 1 are divided into work condition databases J1 to J2. 10 In, such as Figure 3 As shown.

[0078] Step 3: Cut the segments in J1-J 10 to build short-trip libraries K1-K 10 using short-trip method (each short-trip consists of an idle segment and an adjacent motion segment). The short-trip diagram is shown in Figure 4 . The short-trip library is shown in Figure 5 .

[0079] Step 4: Calculate the length of each idle segment and the maximum speed, maximum acceleration, maximum deceleration and motion length of each motion segment in K1-K 10 , and clean the idle and motion segments obtained in Step 3 by deleting the segments that do not meet the conditions. When deleting an idle segment or a motion segment, the corresponding motion or idle segment should also be deleted. Number each motion segment in K1-K 10 . The first segment in K2 is numbered as the last segment in K1 plus 1, and so on.

[0080] The screening rules in this embodiment are as follows:

[0081] 1) Running time: the length of each short-trip motion segment is greater than or equal to 5s

[0082] 2) Acceleration absolute value: less than 4.5m / s 2 ;

[0083] 3) Speed range: 5km / h < v < 130km / h;

[0084] 4) Idle time length: idle time is not more than 200s;

[0085] 5) Missing rate: data missing rate is not more than 5%.

[0086] Step 5: Calculate the two categories of 8 characteristic parameters of short-trip library K1-K 10 and each short-trip segment. The braking parameters include average deceleration, braking time, braking distance, braking initial speed, braking frequency per kilometer; the time length parameters include motion time length, idle time length, total time length. Taking K1 as an example, the characteristics of each segment in K1 are shown in Table 1, and K2-K9 are the same. The characteristics of K1-K 10 are shown in Table 2-1 and Table 2-2.

[0087] Table 1 Short-trip characteristics of working condition library K1

[0088]

[0089]

[0090] Table 2-1 Short-trip library characteristics

[0091]

[0092]

[0093] Table 2-2 Short-travel library characteristics

[0094]

[0095] In this embodiment, braking is determined by the following braking rules:

[0096] 1) deceleration: less than or equal to -0.15 m / s 2 ;

[0097] 2) brake pedal opening: greater than 5%;

[0098] 3) braking duration is not less than 2 s.

[0099] The acceleration and deceleration calculation formula is as follows:

[0100]

[0101] Where a i is in m / s 2 , v i+1 and v i-1 are in km / h, and the acceleration and deceleration values at the beginning and end of the motion segment are both 0 m / s 2 .

[0102] Step 6: Calculate the proportion of short-travel library K1~K 10 low-speed, medium-speed, high-speed motion segments and idle speed segments. Calculate the number of low-speed, medium-speed, high-speed and idle speed segments required in each short-travel library in combination with T1~T 10 In this embodiment, the low-speed, medium-speed and high-speed intervals are divided according to the following rules:

[0103] 1) low-speed interval: the highest speed of the motion segment is less than or equal to 60 km / h;

[0104] 2) medium-speed interval: the highest speed of the motion segment is greater than 60 km / h and less than or equal to 80 km / h;

[0105] 3) high-speed interval: the highest speed of the motion segment is greater than 80 km / h.

[0106] Taking the number of segments required in K1 as an example, the total duration of the typical working condition of the library is T1=408 s, and according to Table 2-1, the duration ratio of the moving segment is 70%, and the duration ratio of the idle segment is 30%. Combined with the duration ratio of low speed, medium speed and high speed, the number of low speed segments n1=408*0.7*0.71 / 59=3.43, the number of medium speed segments n2=408*0.7*0.24 / 120=0.57, and the number of high speed segments n3=408*0.7*0.05 / 151=0.09 can be calculated. After rounding, n1=3, n2=0, n3=0, and the number of idle segments n4=n1+n2+n3=3. The average duration of the idle segment is 408*0.3 / 3=41 s. The number of segments required for each sub-working condition library is shown in Table 3 according to the above method.

[0107] Table 3 Number of segments in different speed intervals of each working condition library

[0108]

[0109]

[0110] Step 7: According to the calculation results of step 5, the moving segments and the corresponding idle segments with an error of 15% or less in the feature parameters and the working condition library to which they belong are selected from K1 to K 10 , respectively, to form the working condition libraries L1 to L 10 .

[0111] Step 8: According to the results of step 6, a corresponding number of moving segments are randomly selected for combination in L1 to L 10 , and an idle segment with a corresponding duration is inserted between the adjacent two moving segments to obtain the typical working condition sets C1 to C 10 of L1 to L 10 . Figure 6 is a typical working condition in C1.

[0112] Step 9: The average speed and average brake deceleration of the typical working conditions in C1 to C 10 are subjected to chi-square test, and the working condition with the optimal average chi-square value is selected as the optimal working condition of the set. The optimal working conditions in C1 to C 10 are connected end to end to obtain a brake working condition curve that can represent the actual road conditions in China. Table 4 shows the chi-square test results of the typical working conditions in C1. From the table, it can be seen that the chi-square value of C1-1 is optimal, which is selected as the optimal working condition of C1. The selection of the optimal working conditions in C2 to C 10 is the same.

[0113] Table 4 Chi-square test results of typical working conditions in C1

[0114] Average vehicle speed chi-square value Average deceleration chi-square value Average chi-square value C1-1 75.58 65.70 57.88 C1-2 72.22 10.56 41.39 C1-3 3.97 75.36 75.47 C1-4 39.27 76.49 5.84 C1-5 39.14 46.02 42.58 C1-6 27.02 4.78 15.90 C1-7 72.00 18.78 45.39 C1-8 29.54 28.25 28.90 C1-9 8.90 7.72 37.30 C1-10 62.42 1.23 31.83 C1-11 31.18 3.44 17.31 C1-12 19.34 13.52 16.43 ..... ..... ...... ...... C1-14 32.31 51.93 42.12

[0115] Step 10: Since the braking condition curves obtained in step 9 are all composed of condition libraries K1~K 10 The present application takes a motion segment in K1 as an example to perform steady-state processing on the condition curves obtained in step 9, and the specific method is as follows:

[0116] 2) According to the braking initial speed, braking time and average braking deceleration of the corresponding segment in step 5, the deceleration section is changed into a uniform deceleration process, and the initial speed of the deceleration section is recorded as v1, and the corresponding time is t2;

[0117] 2) Find the time corresponding to the speed reaching v1 in the acceleration section, recorded as t1;

[0118] 3) Replace the uniform speed section between t1 and t2 with a uniform speed section with a speed of v1;

[0119] 4) Calculate the average speed of each acceleration section;

[0120] 5) Take the average speed of 5km / h and the acceleration of 0.1m / s 2 as the interval to calculate the acceleration cumulative distribution of all motion segments in K1~K 10 ;

[0121] 6) Select the 50% quantile value of the acceleration cumulative distribution corresponding to the average speed in step 5 as the acceleration value of the acceleration section, and change the acceleration section into a uniform acceleration process.

[0122] The segment schematic diagram before and after steady-state processing is shown in Figure 7 .

[0123] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for constructing braking conditions for light-duty vehicles, used for braking non-emission testing; characterized in that: Includes the following steps: S1: Based on the original vehicle data, calculate the duration distribution of a single trip segment, and calculate the duration T1~T corresponding to the typical quantile values. 10 ; S2: T1~T respectively 10 As boundary conditions, the vehicle single trip segment data in step S1 are divided into single trip segment libraries J1~J1 respectively. 10 middle; S3: Use the short-distance method to extract single-trip segment libraries J1~J 10 A single trip of a vehicle is divided into short-stroke segments. Each short-stroke segment consists of an idling segment and an adjacent motion segment, based on J1~J 10 Construct a short-stroke library K1~K 10 ; S4: Calculate the short-stroke libraries K1~K respectively. 10 The data includes the duration of each idle segment and the maximum speed, maximum acceleration, maximum deceleration, and duration of each motion segment. The idle and motion segments obtained in step S3 are then cleaned, and segments that do not meet the filtering rules are deleted. The short-stroke library K1~K... 10 Each motion segment is numbered, and the number of the first segment in K2 is the number of the last segment in K1 plus 1, and so on; S5: Calculate the short-stroke library K1~K 10 The feature parameters for each short-stroke segment include braking parameters and duration parameters. The braking parameters are determined based on the braking rules. S6: Based on the short-stroke library K1~K in step S5 10 Based on the maximum vehicle speed, K1~K 10 The short and medium-speed strokes are divided into low-speed, medium-speed, and high-speed ranges, and the short-speed stroke library K1~K is calculated for each range. 10 The duration percentages of low-to-medium speed, medium speed, high speed motion segments, and idling segments, combined with T1~T 10 Calculate the required number of low-speed segments, medium-speed segments, high-speed segments, and idle segments for each short-stroke library; S7: Based on the calculation results of step S5, in K1~K 10 Motion segments whose characteristic parameters are within 15% of the error between them and their corresponding short-stroke libraries, along with their corresponding idle speed segments, are selected to form the operating condition libraries L1~L2. 10 ; S8: Based on the results of step S6, in the working condition library L1~L 10 A corresponding number of motion segments are randomly selected and combined, and an idling segment of corresponding duration is inserted between two adjacent motion segments to obtain the operating condition library L1~L. 10 Typical operating condition set C1~C 10 ; S9: For typical working condition sets C1~C1 respectively 10 The average vehicle speed and average braking deceleration under typical working conditions are subjected to a chi-square test. The working condition with the optimal average chi-square value is selected as the optimal working condition of the set. Typical working condition sets C1 to C2 are then sequentially selected. 10 By connecting the optimal operating conditions end to end, the braking operating condition curve is obtained; S10: Steady-state processing is performed on the operating condition curves obtained in step S9; The stabilization process in step S10 includes the following steps: S101. Based on the initial braking velocity, braking duration, and average braking deceleration of the corresponding short-stroke segment in step S5, the deceleration segment is transformed into a uniform deceleration process. The initial velocity of the deceleration segment is denoted as v1, and the corresponding time is t2. S102. Find the moment when the speed reaches v1 in the acceleration segment and denote it as t1. S103, the section between t1 and t2 is replaced by a constant speed section with a vehicle speed of v1; S104. Calculate the average vehicle speed for each acceleration phase; S105, with an average speed of 5 km / h and an acceleration of 0.1 m / s². 2 Calculate K1~K as intervals. 10 The cumulative distribution of acceleration at different average velocities across all motion segments; S106. Select the 50th percentile value of the cumulative distribution of acceleration at the corresponding average vehicle speed in step S105 as the acceleration value of the acceleration segment, and transform the acceleration segment into a uniform acceleration process.

2. The method for constructing braking conditions for a light vehicle according to claim 1, characterized in that: In step S2, the vehicle single-trip segment data from step S1 are divided into single-trip segment libraries J1~J1. 10 The process includes the following steps: S21. Determine the duration of a single trip for a vehicle. t Is it in T? i ≤ t <T i+1 Within the range where i=1, 2, ..., 9, if the value is true, then the current vehicle trip segment will be assigned to the single trip segment library J. i+1 If yes, then proceed to step S22; S22. Determine the duration of a single trip for a vehicle. t Is it in t ≥T 10 If yes, discard the current vehicle trip segment; otherwise, proceed to step S23. S23. Determine the single trip duration of the vehicle t Whether it is within t <Within the range of T1, if yes, divide this vehicle trip segment into the single trip segment library J1.

3. The method for constructing braking conditions for a light vehicle according to claim 1, characterized in that: The braking parameters in step S5 include average deceleration, braking duration, braking distance, initial braking speed, and number of braking operations per kilometer; the duration parameters include motion duration, idling duration, and total duration.

4. The method for constructing braking conditions for a light vehicle according to claim 1, characterized in that: The division of low-speed, medium-speed, and high-speed segment intervals in step S6 is based on the following rules: S61a. Determine whether the maximum speed of the motion segment is less than or equal to 60km / h. If yes, the motion segment is classified as a low-speed segment. If no, proceed to step S62a. S62a. Determine whether the maximum speed of the motion segment is greater than 60km / h and less than or equal to 80km / h. If yes, classify the motion segment into the medium speed range and the motion segment is a medium speed motion segment. If no, proceed to step S63a. S63a. Determine whether the maximum speed of the motion segment is greater than 80km / h. If yes, classify the motion segment as a high-speed segment.

5. The method for constructing braking conditions for a light vehicle according to claim 1, characterized in that: The calculation of the required number of low-speed segments, medium-speed segments, high-speed segments, and idle segments in each short-stroke library in step S6 includes the following steps: S61b Calculate the average duration of low-speed segments, average duration of medium-speed segments, and average duration of high-speed segments in each short-stroke library; S62b: The number of low-speed segments is obtained using the formula for calculating the number of low-speed segments; the number of medium-speed segments is obtained using the formula for calculating the number of medium-speed segments; and the number of high-speed segments is obtained using the formula for calculating the number of high-speed segments. S63b: The number of idle segments is obtained by using a formula based on the number of idle segments.

6. The method for constructing braking conditions for a light vehicle according to claim 5, characterized in that: The formula for calculating the number of low-speed segments is: Number of low-speed segments n1 = T i *Percentage of low-speed segments / Average duration of low-speed segments.

7. The method for constructing braking conditions for a light vehicle according to claim 5, characterized in that: The formula for calculating the number of medium-speed segments is: Number of medium-speed segments n2 = T i *Percentage of medium-speed segments / Average duration of medium-speed segments.

8. The method for constructing braking conditions for a light vehicle according to claim 5, characterized in that: The formula for calculating the number of high-speed segments is: Number of high-speed segments n3 = T i *Percentage of high-speed segment duration / Average duration of high-speed segment.

9. The method for constructing braking conditions for a light vehicle according to claim 5, characterized in that: The formula for calculating the number of idle speed segments is: n4 = n1 + n2 + n3 Where n4 is the number of idle speed segments, n1 is the number of low speed segments, n2 is the number of medium speed segments, and n3 is the number of high speed segments.

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