Method for calculating clutch engagement speed

Abstract

The present application relates to a kind of clutch combination speed calculation method, to solve the problem that traditional clutch combination control strategy is not quantified to sliding abrasion power L and the problem of large amount of calculation.The present application includes the following steps: step 1, judge the current state of vehicle, if in starting state, then turn to step 2, if in driving shift state, then turn to step 3;Step 2, the calculation of clutch optimal combination speed when vehicle starts;Step 3, the shift condition when vehicle normally travels;By the maximum combination speed calculation formula of clutch when N gear is combined, the maximum combination speed corresponding to each gear is obtained, and finally the optimal combination speed under each gear is obtained.

Description

Technical Field

[0001] This invention relates to clutch control, and more specifically to a method for calculating clutch engagement speed. Background Technology

[0002] The clutch is a key component in a vehicle's transmission system, serving to connect and disconnect power. Its performance evaluation indicators include impact J and sliding work L. The control objective of the clutch is the engagement speed. Clutch control must balance both impact J and sliding work L, requiring impact J to be within an acceptable range and sliding work L to be as small as possible. However, impact J and sliding work L are a pair of contradictory physical quantities: when impact J is small, sliding work L is large; conversely, when sliding work L is small, impact J is significantly large. The clutch engagement principle is to engage at the fastest possible speed while satisfying the impact J requirement. Clutch engagement speed not only affects shift quality but also has a strong correlation with clutch lifespan and the overall smoothness of the vehicle.

[0003] Traditional clutch engagement control strategies typically employ control algorithms such as fuzzy control, PID control, and dynamic programming. However, none of these algorithms quantify the slippage work L, meaning they fail to fully consider the impact of slippage work L. Furthermore, these algorithms involve a large amount of computation, while the computing power of the vehicle controller is relatively weak. Therefore, traditional clutch engagement control strategies no longer meet current requirements.

[0004] Chinese invention patent application CN102705398A discloses a method for controlling clutch synchronous impact. However, this method does not quantify the sliding friction work L, resulting in unclear results. Summary of the Invention

[0005] This invention provides a method for calculating clutch engagement speed, which solves the problems of traditional clutch engagement control strategies that do not quantify the slippage work L and have excessive computational complexity.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for calculating clutch engagement speed, the steps of which are as follows:

[0008] Step 1: Determine the current state of the vehicle. If it is in the starting state, proceed to Step 2. If it is in the state of shifting gears while driving, proceed to Step 3.

[0009] Step 2: Calculation of the optimal clutch engagement speed when the vehicle starts;

[0010] Step 2.1, obtain the vehicle mass rotation coefficient. Vehicle quality Wheel working radius Clutch friction coefficient Effective working radius of friction plate linearized spring stiffness coefficient N gear main drive ratio Main reducer transmission ratio Mechanical transmission efficiency and maximum impact ;

[0011] Step 2.2: Based on the data obtained in Step 2.1, calculate the maximum clutch engagement speed in N gear. The maximum clutch engagement speed when in neutral (N) gear. The fastest engagement time t is obtained from the distance between the clutch's partial engagement point and the engagement point. 快 ;

[0012] Step 2.3, preset the speed of the clutch driven plate. With the independent variable time The polynomial; and through the impact degree J formula, the sliding work L formula, and the clutch driven plate speed The polynomial yields simplified formulas for the impact intensity J and the grinding work L.

[0013] Step 2.4: Take the value of impact J, and obtain the value of the corresponding sliding work L, the corresponding bonding speed, and the corresponding bonding time through the simplified formula of impact J and sliding work L;

[0014] Step 2.5: Process the impact J and sliding work L obtained in Step 2.4 to select a suitable impact J, as well as the corresponding sliding work L and bonding speed.

[0015] Step 3, Calculation of the optimal clutch engagement speed during gear shifting while the vehicle is in motion:

[0016] Based on the main drive ratio and target speed corresponding to each gear, the maximum clutch engagement speed when engaged in neutral (N) gear is determined. The calculation formula yields the maximum engagement speed corresponding to each gear. Ultimately, the optimal engagement speed for each gear is obtained.

[0017] Furthermore, in step 2.2, the maximum clutch engagement speed in neutral (N) gear. The calculation formula is as follows:

[0018]

[0019] Furthermore, in step 2.3, it is assumed that the speed of the clutch driven plate is... With the independent variable time The polynomial is: a, b, and c are quantities to be determined; when the clutch is not engaged. When the clutch is fully engaged ;

[0020] The simplified formula for the impact intensity J is:

[0021]

[0022] Sliding work The simplified formula is:

[0023]

[0024] in, The angular velocity of the clutch drive disc. For wind resistance, Let t be the moment of inertia of the driven disc of the clutch, and t be time.

[0025] Further, step 2.4 is as follows: Take a series of discrete values ​​for the impact J starting from the minimum value 0, and then obtain the corresponding values ​​of a and b. Through the values ​​of a and b, obtain the corresponding value of the sliding friction work L, the corresponding bonding speed, and the corresponding bonding time.

[0026] Step 2.5 is as follows: The impact intensity J and the sliding friction work L obtained in step 2.4 are standardized. The data obtained after standardization are then processed using the least squares method to obtain the sum of squares corresponding to each impact intensity J. Based on the minimum value obtained from the sum of squares, the corresponding optimal impact intensity J, sliding friction work L, and bonding speed can be determined.

[0027] Furthermore, step 3 is detailed below:

[0028] Step 3.1: Based on the main drive ratio and target speed corresponding to each gear, determine the maximum clutch engagement speed when engaging N gear. The calculation formula yields the maximum engagement speed corresponding to each gear. ; through the maximum engagement speed of the clutch The fastest engagement time t is obtained from the distance between the clutch's partial engagement point and the engagement point. 快 ;

[0029] Maximum clutch engagement speed in neutral (N) The calculation formula is as follows:

[0030]

[0031] Step 3.2: Substitute the time when the clutch is not engaged and the speed of the clutch driven plate, as well as the time when the clutch is fully engaged and the speed of the clutch driven plate, into the formulas for impact degree J, slip work L, and clutch driven plate speed. The polynomial yields simplified formulas for the impact intensity J and the grinding work L.

[0032] Step 3.3: Take a series of discrete values ​​for the impact J starting from the minimum value of 0, and then obtain the corresponding value of the sliding work L, the corresponding bonding speed, and the corresponding bonding time through the simplified formula of impact J and sliding work L.

[0033] Step 3.4: The impact intensity J and the sliding friction work L obtained in Step 3.3 are standardized and processed using the least squares method. The optimal impact intensity J, sliding friction work L and bonding speed are obtained based on the results of the least squares method.

[0034] Furthermore, it also includes step 4, which reflects driving requirements in the clutch engagement speed:

[0035] To express different driving intentions, the combined speed is multiplied by a corresponding weighting factor; the weighting factor is one of: 0.8, 0.9, 1, 1.1, 1.2.

[0036] The beneficial effects of this invention are:

[0037] In this invention, the relationship between the driven disk rotation speed and time t is obtained by calculating the driven disk rotation speed, and then simplified calculation formulas for impact J and sliding wear work L are obtained. By combining the simplified calculation formulas for impact J and sliding wear work L with the expected boundary conditions under various working conditions, the specific values ​​of impact J and sliding wear work L are obtained, providing an accurate calculation method for the values ​​of impact J and sliding wear work L for subsequent calculations.

[0038] The present invention provides a method for calculating the clutch engagement speed, which uses the optimal engagement speed as the control input of the clutch, thereby maximizing the balance between clutch mechanical wear and driver / passenger comfort. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0040] This invention provides a method for calculating clutch engagement speed. Based on the boundary conditions of vehicle start-up and gear shifting, a time-speed polynomial for the clutch driven plate is established. The clutch performance evaluation indicators, impact J and slippage work L, are serialized, and the least squares method is further applied to obtain the optimal clutch engagement speed. Furthermore, the influence of driving requirements on engagement speed is reflected through a weighting factor. The quantification of slippage work L allows its influence to be fully considered when determining the clutch engagement speed. Additionally, the least squares method simplifies the calculations involved in clutch engagement speed applications.

[0041] A method for calculating clutch engagement speed, the process of which is as follows: Figure 1As shown, the specific steps are as follows:

[0042] Step 1: Calculate the optimal clutch engagement speed when starting the vehicle.

[0043] Clutch engagement speed in 2nd gear The calculation formula is as follows:

[0044] ...(1)

[0045] The parameters are as follows:

[0046] Table 1 Examples of Clutch-Related Parameters

[0047]

[0048] Impact strength J range references German standard Since heavy trucks typically start in second gear, and passenger cars should also start in second gear on slippery roads, second gear start-up is used as an example. Substitute the parameters listed in Table 1 into the clutch engagement speed... In the calculation formula, the maximum impact J is set to 10. The calculation shows the maximum clutch engagement speed during second-gear start-up. Assuming the distance from the clutch half-engagement point (where the clutch transmits torque just enough to overcome the vehicle's driving resistance) to the engagement point is 6mm, then the fastest engagement time is 0.8s.

[0049] Assuming the speed of the clutch driven plate With the independent variable time The polynomial is: (Where a, b, and c are quantities to be determined). When the clutch is not engaged, the driven plate rotates at 0 speed; when fully engaged, it rotates at engine idle speed (engine speed is taken as 600 r / min). The expression is:

[0050] ...(2)

[0051] The formula for impact J is:

[0052] ...(3)

[0053] in, This refers to the clutch torque. For wind resistance, The moment of inertia of the clutch driven plate. This is the main drive ratio for gear N.

[0054] Sliding work The formula is:

[0055] ... (4)

[0056] in, The angular velocity of the clutch drive disc. The moment when the clutch driving plate and driven plate just begin to make contact. The moment when the speed of the clutch driven plate is greater than 0. This is the moment when the speeds of the clutch driving plate and driven plate are synchronized.

[0057] Speed ​​of the clutch driven plate Combining the formula and the formula for impact J, we can obtain:

[0058] ... (5)

[0059] Speed ​​of the clutch driven plate Formulas and grinding work Combining the formulas, we get:

[0060] ... (6)

[0061] For a clutch product It has its own inherent parameter values. The value is related to the specific vehicle model. In this embodiment... , The specific calculation results are shown in Table 2 below:

[0062] Table 2 Calculation results of impact intensity J and frictional work L

[0063]

[0064] Based on the calculated impact intensity J and sliding wear work L, the impact intensity J and sliding wear work L are first standardized, and then the least squares method is applied to obtain the minimum distance. Standardization refers to the process of removing dimensions from different physical quantities for comparison. Here, normalization is specifically used.

[0065] After standardizing the impact energy and the grinding energy L, the following matrix is ​​obtained:

[0066]

[0067] The values ​​in the first row of the matrix above represent the results after standardizing the impact intensity J; the values ​​in the second row represent the results after standardizing the frictional work L. The least squares method is applied to the standardized data to obtain the sum of squared distances corresponding to each impact intensity J, as follows:

[0068]

[0069] From the vector above, we can see that the minimum value is 0.003, corresponding to an impact intensity J of 7. Therefore, when the impact intensity J is 7, the combined impact intensity J and the frictional work L are optimal. At this point, the bonding speed is 5.256. To obtain a more accurate value for the impact intensity J, the impact intensity J can be divided into smaller steps, and then the above calculation process can be used to obtain a more accurate value.

[0070] Using the engagement speed to control the clutch during vehicle start-up can increase clutch lifespan and improve overall vehicle smoothness.

[0071] Step 2: Calculation of the optimal clutch engagement speed during vehicle gear shifting

[0072] When a vehicle shifts gears, the transmission ratio changes abruptly. Because the shift time is very short and the vehicle's inertia is large, the vehicle speed is assumed to remain constant during the shift. This abrupt change in transmission ratio is reflected in the clutch as a change in the driven disc's speed. The driven disc's speed before the shift is... for:

[0073] ... (7)

[0074] in, Refers to vehicle speed, This refers to the gear ratio of the transmission before a gear change.

[0075] Speed ​​of the driven plate after shifting gears for:

[0076] ... (8)

[0077] in, This represents the gear ratio of the transmission before the gear shift.

[0078] The engine speed changes drastically before and after the gear shift:

[0079] ... (9)

[0080] As can be seen from the above formula, due to the different transmission ratios of the new and original gears, there is a significant speed difference when the clutch driving plate and driven plate first engage. If speed synchronization is achieved through clutch slippage, it will lead to severe clutch wear. The usual solution is to make the speeds of the clutch driving and driven plates close to or equal before engaging a new gear, thus accommodating the sudden change in transmission ratio, reducing vehicle impact and clutch wear during gear shifting, and improving shift quality. Assuming a specific target gear is to be engaged, the engine speed in that target gear is taken as the target speed. Table 3 lists the calculated target engine speeds for various gears of a certain vehicle model:

[0081] Table 3 Calculation values ​​of engine target speed for each gear

[0082]

[0083] The impact J under shifting conditions is expressed as:

[0084] ... (10)

[0085] In the formula The translational and rotational masses of the vehicle are equivalent to the moment of inertia on the transmission input shaft. , .

[0086] During the torque growth phase of clutch engagement, using the impact J as the boundary condition and combining Equation 1, the maximum engagement speed for different gears (assuming the transmission has 12 gears) is obtained, as shown in Table 4:

[0087] Table 4 Maximum Clutch Engagement Speed ​​in Each Gear

[0088]

[0089] Based on the calculated maximum engagement speed and fastest engagement time for each gear, the time when the clutch is not engaged and the speed of the clutch driven plate, as well as the time when the clutch is fully engaged and the speed of the clutch driven plate, are substituted into the formulas for impact J, slip work L, and clutch driven plate speed. The polynomial yields simplified formulas for the impact intensity J and the frictional work L; by taking values ​​for the impact intensity J and using the simplified formulas for the impact intensity J and the frictional work L, the corresponding frictional work L, the corresponding bonding speed, and the corresponding bonding time can be obtained.

[0090] The obtained impact degree J and corresponding sliding work L are standardized and processed by the least squares method to select the optimal impact degree J. Based on the optimal impact degree J, the corresponding optimal sliding work L and optimal bonding speed are obtained.

[0091] Step 3: The driving requirements are reflected in the clutch engagement speed.

[0092] The effects of accelerator pedal displacement and accelerator opening on the clutch can be summarized as driving demand: to respond to an urgent desire to drive, the clutch should engage quickly; conversely, it should engage at a slower speed. To represent different driving intentions, the engagement speed is multiplied by a corresponding weighting factor, as shown in Table 5. During autonomous driving, the driver can input driving intentions and obtain the most suitable clutch engagement speed based on the corresponding weighting factor.

[0093] Table 5. Conversion of Driving Intent into Weighting Factors

[0094] .

Claims

1. A method for calculating clutch engagement speed, characterized in that, The steps are as follows: Step 1: Determine the current state of the vehicle. If it is in the starting state, proceed to Step 2. If it is in the state of shifting gears while driving, proceed to Step 3. Step 2: Calculation of the optimal clutch engagement speed when the vehicle starts; Step 2.1, obtain the vehicle mass rotation coefficient. Vehicle quality Wheel working radius Clutch friction coefficient Effective working radius of friction plate linearized spring stiffness coefficient N gear main drive ratio Main reducer transmission ratio Mechanical transmission efficiency and maximum impact ; Step 2.2: Based on the data obtained in Step 2.1, calculate the maximum clutch engagement speed in N gear. The maximum clutch engagement speed when in neutral (N) gear. The fastest engagement time t is obtained from the distance between the clutch's partial engagement point and the engagement point. 快 ; Maximum clutch engagement speed in neutral (N) The calculation formula is as follows: ； Step 2.3, preset the speed of the clutch driven plate. With the independent variable time The polynomial; and through the impact degree J formula, the sliding work L formula, and the clutch driven plate speed The polynomial yields simplified formulas for the impact intensity J and the grinding work L. Assuming the speed of the clutch driven plate With the independent variable time The polynomial is: a, b, and c are quantities to be determined; when the clutch is not engaged. When the clutch is fully engaged ; The simplified formula for the impact intensity J is: Sliding work The simplified formula is: in, The angular velocity of the clutch drive disc. For wind resistance, Let t be the moment of inertia of the clutch driven disc, and t be time. Step 2.4: Take the value of impact J, and obtain the value of the corresponding sliding work L, the corresponding bonding speed, and the corresponding bonding time through the simplified formula of impact J and sliding work L; Step 2.5: Process the impact J and sliding work L obtained in Step 2.4 to select a suitable impact J, as well as the corresponding sliding work L and bonding speed. Step 3, Calculation of the optimal clutch engagement speed during gear shifting while the vehicle is in motion: Based on the main drive ratio and target speed corresponding to each gear, the maximum clutch engagement speed when engaged in neutral (N) gear is determined. The calculation formula yields the maximum engagement speed corresponding to each gear. Ultimately, the optimal engagement speed for each gear is obtained.

2. The method for calculating clutch engagement speed according to claim 1, characterized in that, Step 2.4 is as follows: Take a series of discrete values ​​for the impact J starting from the minimum value 0, and then obtain the corresponding values ​​of a and b. Through the values ​​of a and b, obtain the corresponding sliding work L, the corresponding bonding speed, and the corresponding bonding time. Step 2.5 is as follows: The impact intensity J and the sliding friction work L obtained in step 2.4 are standardized. The data obtained after standardization are then processed using the least squares method to obtain the sum of squares corresponding to each impact intensity J. Based on the minimum value obtained from the sum of squares, the corresponding optimal impact intensity J, sliding friction work L, and bonding speed can be determined.

3. The method for calculating clutch engagement speed according to claim 1 or 2, characterized in that: Step 3 is as follows: Step 3.1: Based on the main drive ratio and target speed corresponding to each gear, determine the maximum clutch engagement speed when engaging N gear. The calculation formula yields the maximum engagement speed corresponding to each gear. ; the maximum engagement speed of the clutch corresponding to each gear The fastest engagement time t is obtained by measuring the distance from the clutch's partial engagement point to its full engagement point. 快 ; Maximum clutch engagement speed in neutral (N) The calculation formula is as follows: Step 3.2: Substitute the time when the clutch is not engaged and the speed of the clutch driven plate, as well as the time when the clutch is fully engaged and the speed of the clutch driven plate, into the formulas for impact degree J, slip work L, and clutch driven plate speed. The polynomial yields simplified formulas for the impact intensity J and the grinding work L. Step 3.3: Take a series of discrete values ​​for the impact J starting from the minimum value of 0, and then obtain the corresponding value of the sliding work L, the corresponding bonding speed, and the corresponding bonding time through the simplified formula of impact J and sliding work L. Step 3.4: The impact intensity J and the sliding friction work L obtained in Step 3.3 are standardized and processed using the least squares method. The optimal impact intensity J, sliding friction work L and bonding speed are obtained based on the results of the least squares method.

4. The method for calculating clutch engagement speed according to claim 1, characterized in that, It also includes step 4, which reflects driving requirements in terms of clutch engagement speed: To express different driving intentions, the combined speed is multiplied by a corresponding weighting factor; the weighting factor is one of: 0.8, 0.9, 1, 1.1, 1.2.

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