Automatic transmission shift control method

Abstract

The present invention discloses a method for controlling gear disengagement in an automatic transmission. The main design concept of the present invention is that after the gear selection electric cylinder moves the gear selection push rod to the shift fork position point where the control gear position is located, the current shift fork is pushed from the in-gear position to the intermediate position according to the control gear position; based on the control gear position, the first shift electric cylinder and the second shift electric cylinder are determined to be forward electric cylinders or reverse electric cylinders; and at multiple stages in the orderly gear disengagement process, the forward electric cylinder force and the reverse electric cylinder force are coordinated and controlled based on the shift fork movement speed and the shift displacement position. The present invention can ensure smooth gear disengagement during vehicle shifting, while taking into account the influence of the gear selection and shifting mechanical structure on the resistance during the gear disengagement process. By controlling the forward and reverse electric cylinder forces at different stages, the impact on the gear sleeve, meshing teeth, and synchronizer ring during the gear disengagement process is reduced, thereby extending the service life of the clutch.

Description

Technical Field

[0001] The present invention relates to the field of gear shift control of a transmission, and in particular to a gear shift control method for an automatic transmission. Background Art

[0002] The process of disengaging gear is actually the process of separating the gear sleeve from the engaging teeth, that is, the process of moving the gear sleeve to the neutral position within a given time is called disengaging gear (shifting from the current gear to the neutral gear during the gear shifting operation). The driving force transmission path is the same as that of engaging gear. The shift fork pushes the gear sleeve to move, and the component force generates torque to make the gear engaging teeth rotate a small angle, and the gear sleeve disengages.

[0003] The resistance to shifting gears is related to the system inertia (parts structure), drag torque (oil temperature, speed, clutch state, etc.), and other aspects include the resistance of the synchronizer slider, the resistance of the shift fork positioning pin (spring), the corresponding friction force and the deformation of the shift fork. During the linear sliding process of the shift fork (shaft), the overturning torque acts when the shift fork is under force. The shift fork (shaft) puts pressure on the shift fork (shaft) bushing or the shift fork shaft hole on the housing, and the sliding generates friction resistance, and there is also a deformation effect. Summary of the Invention

[0004] In view of the above, the present invention aims to provide a method for controlling shifting of an automatic transmission to solve the above-mentioned technical problems.

[0005] The technical solution adopted in the present invention is as follows:

[0006] The present invention provides a method for controlling shifting of an automatic transmission, which includes:

[0007] After the gear selection electric cylinder moves the gear selection push rod to the shift fork position point where the gear is controlled, the current shift fork is pushed from the in-gear position to the middle position according to the gear control position;

[0008] Based on the control gear position, determining whether the first shift electric cylinder and the second shift electric cylinder are forward electric cylinders or reverse electric cylinders;

[0009] From the beginning to the end of the gear shifting process, the forward and reverse electric cylinder forces are coordinated and controlled based on the shift fork movement speed and the gear shift displacement position.

[0010] In at least one possible implementation, in the first stage of the gear shifting control, the forward electric cylinder force is the sum of the estimated friction force obtained by querying a preset mapping table based on the desired gear, the initial value of the shifting force, and the growth rate over time.

[0011] In at least one possible implementation manner, in the first stage of the gear disengagement control, the reverse electric cylinder force is 0.

[0012] In at least one possible implementation method, in the second stage of gear disengagement control, the forward electric cylinder force is: the sum of the forward force at the previous moment and the growth rate over time obtained by querying the preset mapping table of shift fork displacement and shift fork angular velocity, and the forward force in this stage does not exceed the preset maximum forward force value.

[0013] In at least one possible implementation, in the second stage of the gear disengagement control, the reverse electric cylinder force is: in the preset low temperature mode, the reverse electric cylinder force is 0; in the preset normal mode, the reverse electric cylinder force obtains a preset constant force according to the desired gear position lookup table.

[0014] In at least one possible implementation, in the third stage of the gear disengagement control, during the movement to the neutral position under the action of the delayed forward current, when the gear sleeve approaches the neutral position and the forward speed is greater than the established standard, a reverse electric cylinder force is provided to avoid gear disengagement overshoot.

[0015] In at least one possible implementation, in the third stage of the gear disengagement control, the positive electric cylinder force is:

[0016] At the moment of entering the third stage, the positive electric cylinder force is equal to the difference between the positive electric cylinder force at the previous moment and the first gain obtained by looking up the table of the desired gear position and shift angular velocity;

[0017] At the next moment of the third stage, if the shift angular velocity is greater than the preset first angular velocity threshold, the positive cylinder force is equal to the difference between the positive cylinder force at the previous moment and the second gain obtained by looking up the table based on the desired gear position and shift angular velocity. If the difference is negative, the positive cylinder force is set to 0.

[0018] If the shift angular velocity is less than or equal to the first angular velocity threshold: when the shift angular velocity is less than the preset second angular velocity threshold, the forward electric cylinder force is equal to the forward electric cylinder force at the previous moment and the third gain obtained by looking up the table of desired gear position and shift angular velocity; when the shift angular velocity is greater than or equal to the preset second angular velocity threshold, the forward electric cylinder force is equal to the forward electric cylinder force at the previous moment.

[0019] In at least one possible implementation, in the third stage of the gear disengagement control, the reverse electric cylinder force is:

[0020] When entering the third stage, the reverse electric cylinder force is 0;

[0021] At the next moment of entering the third stage, if the angular velocity is greater than the preset first angular velocity threshold and the forward electric cylinder force = 0, the reverse electric cylinder force is equal to the sum of the reverse electric cylinder force at the previous moment and the fourth gain obtained by looking up the table of the desired gear position and the shift angular velocity. If the sum is greater than or equal to the preset maximum reverse force value for this stage, the reverse electric cylinder force is the said maximum reverse force value.

[0022] If the angular velocity is greater than the preset first angular velocity threshold and the forward electric cylinder force = 0, then when the angular velocity is less than the second angular velocity threshold and the forward electric cylinder force is not 0, the reverse electric cylinder force is 0; when the angular velocity is not less than the second angular velocity threshold and the forward electric cylinder force is not 0, the reverse electric cylinder force is equal to the reverse electric cylinder force at the previous moment.

[0023] In at least one possible implementation, in the fourth stage of the gear disengagement control, the forward electric cylinder force is:

[0024] If the angular displacement is less than or equal to the preset first angular displacement threshold, the positive electric cylinder force is 0;

[0025] If both the angular acceleration is less than or equal to the angular acceleration limit obtained by looking up the desired gear position and angular displacement table, the angular velocity is less than or equal to the angular velocity limit obtained by looking up the desired gear position and angular displacement table, and the reverse electric cylinder force is 0, then the forward electric cylinder force is equal to the sum of the reverse electric cylinder force at the previous moment, the estimated friction force obtained by looking up the desired gear position table, the deviation value obtained by looking up the desired gear position, angular displacement, and angular velocity table, and the compensation value obtained by looking up the desired gear position, angular displacement, and angular velocity table.

[0026] If the conditions that the angular acceleration is less than or equal to the angular acceleration limit obtained by looking up the desired gear position and angular displacement table and the angular velocity is less than or equal to the angular velocity limit obtained by looking up the desired gear position and angular displacement table are not simultaneously met, and the reverse electric cylinder force is 0, then the forward electric cylinder force is equal to the difference between the forward electric cylinder force at the previous moment and the deviation value obtained by looking up the desired gear position and angular velocity table, and the forward electric cylinder force is not greater than 0.

[0027] In at least one possible implementation, in the fourth stage of the gear disengagement control, the reverse electric cylinder force is:

[0028] If the angular displacement is less than or equal to the preset second angular displacement threshold, the reverse electric cylinder force is 0;

[0029] If both the angular acceleration is greater than or equal to the angular acceleration limit value obtained by looking up the desired gear position and angular displacement table, the angular velocity is greater than or equal to the angular velocity limit value obtained by looking up the desired gear position and angular displacement table, and the forward electric cylinder force is 0, then the reverse electric cylinder force is equal to the sum of the forward electric cylinder force at the previous moment, the estimated friction force obtained by looking up the desired gear position table, the deviation value obtained by looking up the desired gear position, angular displacement, and angular velocity table, and the compensation value obtained by looking up the desired gear position, angular displacement, and angular velocity table.

[0030] If the conditions that the angular acceleration is greater than or equal to the angular acceleration limit obtained by looking up the desired gear position and angular displacement table and the angular velocity is greater than or equal to the angular velocity limit obtained by looking up the desired gear position and angular displacement table are not simultaneously met, and the forward electric cylinder force is 0, then the reverse electric cylinder force is equal to the difference between the reverse electric cylinder force at the previous moment and the deviation value obtained by looking up the desired gear position and angular velocity table, and the reverse electric cylinder force is not greater than 0.

[0031] Compared to the prior art, the main design concept of this invention lies in that, after the shift selector cylinder moves the shift selector push rod to the shift fork position corresponding to the control gear position, the current shift fork is pushed from the in-gear position to the intermediate position according to the control gear position; based on the control gear position, the first and second shift cylinders are determined to be forward or reverse cylinders; and at multiple stages during the orderly shift disengagement process, the forward and reverse cylinder forces are coordinated and controlled based on the shift fork movement speed and shift displacement position. This invention ensures smooth shifting during vehicle shifting while also taking into account the impact of the shift selector mechanical structure on the resistance during the shift disengagement process. By controlling the forward and reverse cylinder forces at different stages, the impact on the gear sleeve, meshing teeth, and synchronizer ring during the shift disengagement process is reduced, thereby extending the service life of the clutch.

[0032] Furthermore, the overshoot of gear disengagement is controlled to prevent the gear sleeve from impacting the coaxial reverse gear synchronizer ring or meshing teeth due to over-gearing, and to prevent the coaxial reverse gear from being directly engaged during the gear disengagement process, so that the synchronizer gear sleeve is smoothly separated from the engaging teeth and synchronizer ring during the gear disengagement process, reducing the separation impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0034] Figure 1 A flow chart of an automatic transmission shift control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0036] The present invention proposes an embodiment of an automatic transmission shift control method, specifically, Figure 1 shown, including:

[0037] Step S1: After the gear selection electric cylinder moves the gear selection push rod to the shift fork position point where the control gear position is located, the current shift fork is pushed from the in-gear position to the middle position according to the control gear position;

[0038] Step S2: determining whether the first shift electric cylinder and the second shift electric cylinder are forward electric cylinders or reverse electric cylinders based on the control gear position;

[0039] Here is an example: if the control gear is 1 / 3 / 5, the first shift cylinder is the forward cylinder and the second shift cylinder is the reverse cylinder; if the control gear is 2 / 4 / 6 / R, the second shift cylinder is the forward cylinder and the first shift cylinder is the reverse cylinder.

[0040] Step S3: From the beginning to the end of the gear shifting process, based on the shift fork movement speed and the gear shifting displacement position, coordinately control the forward electric cylinder and the reverse electric cylinder to generate the gear shifting force required for the gear shifting process.

[0041] The overall idea is: when the shift fork moves too fast, switch to controlling the reverse electric cylinder; if the shift fork moves slowly and the shift displacement has not reached the middle position, continue to control the forward electric cylinder until the shift displacement reaches the middle position.

[0042] The specific implementation process of the above embodiment can be referred to as follows:

[0043] The unblocking control process can be specifically named as the following four stages in sequence: initial stage Init, separation stage DisEngmt, change stage Ramp, and ending stage Final;

[0044] (1) The Init stage is the first stage. When the shift fork is in the gear position, there is a certain gap between the edge of the gear sleeve and the cone angle of the gear sleeve and the cone angle of the mating gear. The main goal of the Init stage is to eliminate the gap between the shift fork and the gear sleeve and the gap between the gear sleeve and the mating gear ring, overcome the static friction of the system and establish sliding friction.

[0045] The first stage forward electric cylinder force control idea is: the forward electric cylinder force sets an estimated friction force F obtained by looking up the desired gear table 摩 , plus an initial shift force value F obtained by looking up the desired gear table 初 And it grows with time at the growth rate K obtained by looking up the desired gear table, that is, F 正 =F 摩 +F 初 +K*t; The control idea of ​​the reverse electric cylinder force in the first stage is: the reverse electric cylinder force is set to 0;

[0046] The control strategy for exiting the first stage is: when the shift fork displacement X>X ExitRelsInit and the shift fork angular velocity V 角 >V ExitRelsInit When the duration exceeds the limit, it enters the DisEngmt stage.

[0047] (2) The DisEngmt stage is the second stage. The main control target is to push the gear sleeve through the shift fork so that the gear sleeve cone angle and the combined tooth cone angle are staggered and separated. The exit angular displacement of the second stage is set according to the minimum statistical value of the staggered position of the gear sleeve cone angle and the combined tooth cone angle. The shift fork in the second stage overcomes the resistance formed by the positioning pin and the groove, the drag resistance of the gear sleeve and the combined tooth cone angle, the friction force of the shift fork (shaft), and the resistance of the synchronizer slider. This process determines the maximum disengagement force F 摘 =F 销 +F 拖 +F 摩 +F 同 .

[0048] The control idea of ​​the reverse electric cylinder force in the second stage is: the reverse electric cylinder force is 0 in low temperature mode, and the reverse electric cylinder force in normal mode is obtained by looking up the table according to the expected gear position to obtain a constant force; the control idea of ​​the forward electric cylinder force in the second stage is: the forward electric cylinder force is equal to the forward force F at the previous moment 正_Z Plus the growth rate K obtained by looking up the table of shift fork displacement and shift fork angular velocity as time increases, that is, F 正 =F 正_Z +K*t, and F 正 ≤F 正max , F of different gears 正max It can be obtained by looking up the desired gear table.

[0049] The control idea of ​​exiting the second stage is: when the angular displacement X is satisfied 角 ≤X ExitRelsDisEngmt , and satisfy V ExitRelsDisEngmt ≤V 角 <V ExitRelsDisEngmtToFinal When the gear is disengaged, the process normally exits DisEngmt and enters the Ramp phase; and when the angular displacement X is satisfied 角 ≤X ExitRelsDisEngmt , and the angular velocity V 角 ≥V ExitRelsDisEngmtToFinal When the block is released, the process skips the Ramp phase, exits DisEngmt, and directly enters the Final phase.

[0050] (3) The ramp stage is the third stage. At this time, the coupling teeth and the gear sleeve cone angle have been separated. After that, the maximum force for shifting gears is mainly the shift fork positioning pin overcoming the groove force and maintaining linear movement. The main control goal of this third stage is that the gear sleeve continues to move toward the neutral position under the action of the delayed forward current. When the gear sleeve approaches the neutral position and the forward speed is too high, the appropriate reverse electric cylinder force is applied in time to ensure that the gear can be shifted to the neutral position smoothly without overshooting and the phenomenon of symmetrical gear shifting.

[0051] The third stage forward electric cylinder force control idea is: just entering the Ramp stage forward electric cylinder force F 正Equal to the positive electric cylinder force F at the previous moment 正_Z Subtract the first gain F obtained by looking up the table of desired gear and shift angular velocity 正DwnGrdt , that is, F 正 =F 正_Z -F 正DwnGrdt ; At the next moment of entering the Ramp phase, if the shift angular velocity V 角 >V UpOfAngSpdInRamp , then the positive electric cylinder force F 正 Equal to the positive electric cylinder force F at the previous moment 正_Z Subtract the second gain F obtained by looking up the table of desired gear and shift angular velocity 正DwnGrdt2 , that is, F 正 =F 正_Z -F 正DwnGrdt2 , if the difference is negative, then F 正 =0;

[0052] If V 角 ≤V UpOfAngSpdInRamp ①If V 角 <V DwnOfAngSpdInRamp , then the positive electric cylinder force F 正 Equal to the positive electric cylinder force F at the previous moment 正_Z Add the third gain F obtained by looking up the table of desired gear and shift angular velocity 正UpGrdt , that is, F 正 =F 正_Z +F 正UpGrdt ② If V 角 ≥V DwnOfAngSpdInRamp , then the positive electric cylinder force F 正 Equal to the positive electric cylinder force F at the previous moment 正_Z , that is, F 正 =F 正_Z .

[0053] The control idea of ​​the reverse electric cylinder force in the third stage is: when entering the Ramp stage, the reverse electric cylinder force F 反 =0; at the next moment of entering the Ramp phase, if the angular velocity V 角 >V UpOfAngSpdInRamp and F 正 =0, then the reverse electric cylinder force F 反 Equal to the reverse electric cylinder force F at the previous moment 反_Z Add the fourth gain F obtained by looking up the table of desired gear and shift angular velocity 反UpGrdt , that is, F 反 =F 反_Z +F 反UpGrdt , if F 反 ≥F 反maxInRamp , then F 反 =F 反maxInRamp ;

[0054] If the angular velocity V is not satisfied at the same time 角 >V UpOfAngSpdInRamp and F 正 =0, ①If the angular velocity V 角 <V DwnOfAngSpdInRamp And F 正 ≠0, then F 反 =0;②If the angular velocity V is not satisfied 角 <V DwnOfAngSpdInRamp And F 正 ≠0, then F 反 =F 反_Z .

[0055] The control strategy for exiting the third stage is: satisfying the angular displacement X≤X ExitRamp After the conditions are met, the gear shifting process can exit the Ramp and enter the Final stage normally; if the angular displacement X ExitRamp <X<X ExitRelsRampToFinal , and the angular velocity satisfies V 角 ≥V ExitRelsRampToFinal The gear-shifting process can exit Ramp and enter the Final stage normally and quickly.

[0056] (4) The final stage is the fourth stage, and its main control goal is to ensure that the final gear position stops at the neutral position, which is the theoretical position where the gear is fully disengaged.

[0057] The control idea of ​​the positive electric cylinder force in the fourth stage is: if the angular displacement X 角 ≤X NoPosvFinalRels , then F 正 =0; if angular acceleration a is satisfied at the same time 角 Less than or equal to the desired gear position and angular displacement X 角 The angular acceleration limit a obtained by looking up the table PosvActRelsFinal And the angular velocity V 角 Less than or equal to the angular velocity limit V obtained by looking up the table based on the desired gear position and angular displacement PosvActRelsFinal And F 反 =0, then the positive electric cylinder force F 正 Equal to the reverse electric cylinder force F at the previous moment 反_Z Plus an estimated friction force F obtained by looking up the desired gear table 摩 , plus a deviation value F obtained by looking up the table of desired gear position, angular displacement and angular velocity 正Offs , plus a compensation value F obtained by looking up the table of desired gear position, angular displacement and angular velocity 正Comp , that is, F 正 =F 反_Z +F 摩 +F 正Offs +F 正Comp ;

[0058] Otherwise, the positive electric cylinder force F 正 Equal to the positive electric cylinder force F at the previous moment 正_Z Subtract a deviation value F obtained by looking up the table of desired gear and angular velocity DecOfPosvRelsFinal , that is, F 正 =F 正_Z -F DecOfPosvRelsFinal , and F 正 ≤0.

[0059] The control idea of ​​the reverse electric cylinder force in the fourth stage is: if the angular displacement X 角 ≤X NoNegvFinalRels , then F 反 =0; if angular acceleration a is satisfied at the same time 角 Greater than or equal to the desired gear position and angular displacement X 角 The angular acceleration limit a obtained by looking up the table NegvActRelsFinal And the angular velocity V 角 Greater than or equal to the angular velocity limit V obtained by looking up the table based on the desired gear position and angular displacement NegvActRelsFinal And F 正 =0, then the reverse electric cylinder force F 反 Equal to the positive electric cylinder force F at the previous moment 正_Z Plus an estimated friction force F obtained by looking up the desired gear table 摩 , plus a deviation value F obtained by looking up the table of desired gear position, angular displacement and angular velocity 反Offs , plus a compensation value F obtained by looking up the table of desired gear position, angular displacement and angular velocity 反Comp , that is, F 反 =F 正_Z +F 摩 +F 反Offs +F 反Comp ;

[0060] Otherwise, the reverse electric cylinder force F 反 Equal to the reverse electric cylinder force F at the previous moment 反_Z Subtract a deviation value F obtained by looking up the table of desired gear and angular velocity DecOfNegvRelsFinal , that is, F 正 =F 正_Z -F DecOfNegvRelsFinal , and F 反 ≤0.

[0061] The control strategy for exiting the fourth stage is: satisfying the absolute value of the angular displacement |X 角 |≤X ExitFinalRels and the absolute value of the angular velocity |V 角 |≤V ExitFinalRels , and exit the Final stage after the duration exceeds the preset limit.

[0062] In summary, the main design concept of the present invention is that after the shift selector cylinder moves the shift selector push rod to the shift fork position point where the control gear position is located, the current shift fork is pushed from the in-gear position to the intermediate position according to the control gear position; based on the control gear position, the first shift cylinder and the second shift cylinder are determined to be forward cylinders or reverse cylinders; and at multiple stages in the orderly shifting process, the forward cylinder force and the reverse cylinder force are coordinated and controlled based on the shift fork movement speed and shift displacement position. This invention can ensure smooth shifting during vehicle shifting, while taking into account the impact of the shift selector mechanical structure on the resistance during the shifting process. By controlling the forward and reverse cylinder forces at different stages, the impact on the gear sleeve, meshing teeth, and synchronizer ring during the shifting process is reduced, thereby extending the service life of the clutch.

[0063] In the embodiment of the present invention, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a, b and c, where a, b, c can be single or multiple.

[0064] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred modes can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A method for controlling shifting of an automatic transmission, characterized in that: include: After the gear selection electric cylinder moves the gear selection push rod to the shift fork position point where the gear is controlled, the current shift fork is pushed from the in-gear position to the middle position according to the gear control position; Based on the control gear position, determining whether the first shift electric cylinder and the second shift electric cylinder are forward electric cylinders or reverse electric cylinders; From the beginning to the end of the gear shifting process, the forward and reverse electric cylinder forces are coordinated and controlled based on the shift fork movement speed and the shift displacement position. The above includes: in the first stage of the gear shifting control, the forward electric cylinder force is: the sum of the estimated friction force obtained by querying the preset mapping table of the desired gear, the initial value of the gear shifting force, and the growth rate over time; In the second stage of the shift disengagement control, the positive electric cylinder force is the sum of the positive force at the previous moment and the growth rate over time obtained by querying the preset mapping table of the shift fork displacement and the shift fork angular velocity. The positive force in this stage does not exceed the preset maximum positive force value. In the third stage of gear disengagement control, the positive electric cylinder force is: At the moment of entering the third stage, the positive electric cylinder force is equal to the difference between the positive electric cylinder force at the previous moment and the first gain obtained by looking up the table of the desired gear position and shift angular velocity; At the next moment of the third stage, if the shift angular velocity is greater than the preset first angular velocity threshold, the positive cylinder force is equal to the difference between the positive cylinder force at the previous moment and the second gain obtained by looking up the table based on the desired gear position and shift angular velocity. If the difference is negative, the positive cylinder force is set to 0. If the shift angular velocity is less than or equal to the first angular velocity threshold: when the shift angular velocity is less than the preset second angular velocity threshold, the forward electric cylinder force is equal to the forward electric cylinder force at the previous moment and the third gain obtained by looking up the table of desired gear position and shift angular velocity; when the shift angular velocity is greater than or equal to the preset second angular velocity threshold, the forward electric cylinder force is equal to the forward electric cylinder force at the previous moment.

2. The automatic transmission shift control method according to claim 1, characterized in that: In the first stage of gear disengagement control, the reverse electric cylinder force is 0.

3. The automatic transmission shift control method according to claim 1, characterized in that: In the second stage of the gear disengagement control, the reverse electric cylinder force is: in the preset low temperature mode, the reverse electric cylinder force is 0; in the preset normal mode, the reverse electric cylinder force obtains a preset constant force according to the desired gear position lookup table.

4. The automatic transmission shift control method according to claim 1, characterized in that: In the third stage of the gear disengagement control, when the gear sleeve moves to the neutral position under the action of the delayed forward current and the forward speed is greater than the established standard, a reverse electric cylinder force is provided to avoid overshoot of the gear disengagement.

5. The automatic transmission shift-off control method according to claim 1, characterized in that: In the third stage of the gear shift control, the reverse electric cylinder force is: When entering the third stage, the reverse electric cylinder force is 0; At the next moment of entering the third stage, if the angular velocity is greater than the preset first angular velocity threshold and the forward electric cylinder force is 0, the reverse electric cylinder force is equal to the sum of the reverse electric cylinder force at the previous moment and the fourth gain obtained by looking up the table of the desired gear position and the shift angular velocity. If the sum is greater than or equal to the preset maximum reverse force value for this stage, the reverse electric cylinder force is the said maximum reverse force value. If the angular velocity is greater than the preset first angular velocity threshold and the forward electric cylinder force = 0, then when the angular velocity is less than the second angular velocity threshold and the forward electric cylinder force is not 0, the reverse electric cylinder force is 0; when the angular velocity is not less than the second angular velocity threshold and the forward electric cylinder force is not 0, the reverse electric cylinder force is equal to the reverse electric cylinder force at the previous moment.

6. The automatic transmission shift-off control method according to claim 1, characterized in that: In the fourth stage of gear disengagement control, the positive electric cylinder force is: If the angular displacement is less than or equal to the preset first angular displacement threshold, the positive electric cylinder force is 0; If both the angular acceleration is less than or equal to the angular acceleration limit obtained by looking up the desired gear position and angular displacement table, the angular velocity is less than or equal to the angular velocity limit obtained by looking up the desired gear position and angular displacement table, and the reverse electric cylinder force is 0, then the forward electric cylinder force is equal to the sum of the reverse electric cylinder force at the previous moment, the estimated friction force obtained by looking up the desired gear position table, the deviation value obtained by looking up the desired gear position, angular displacement, and angular velocity table, and the compensation value obtained by looking up the desired gear position, angular displacement, and angular velocity table. If the conditions that the angular acceleration is less than or equal to the angular acceleration limit obtained by looking up the desired gear position and angular displacement table and the angular velocity is less than or equal to the angular velocity limit obtained by looking up the desired gear position and angular displacement table are not simultaneously met, and the reverse electric cylinder force is 0, then the forward electric cylinder force is equal to the difference between the forward electric cylinder force at the previous moment and the deviation value obtained by looking up the desired gear position and angular velocity table, and the forward electric cylinder force is not greater than 0.

7. The automatic transmission shift-off control method according to claim 6, characterized in that: In the fourth stage of gear disengagement control, the reverse electric cylinder force is: If the angular displacement is less than or equal to the preset second angular displacement threshold, the reverse electric cylinder force is 0; If both the angular acceleration is greater than or equal to the angular acceleration limit value obtained by looking up the desired gear position and angular displacement table, the angular velocity is greater than or equal to the angular velocity limit value obtained by looking up the desired gear position and angular displacement table, and the forward electric cylinder force is 0, then the reverse electric cylinder force is equal to the sum of the forward electric cylinder force at the previous moment, the estimated friction force obtained by looking up the desired gear position table, the deviation value obtained by looking up the desired gear position, angular displacement, and angular velocity table, and the compensation value obtained by looking up the desired gear position, angular displacement, and angular velocity table. If the conditions that the angular acceleration is greater than or equal to the angular acceleration limit obtained by looking up the desired gear position and angular displacement table and the angular velocity is greater than or equal to the angular velocity limit obtained by looking up the desired gear position and angular displacement table are not simultaneously met, and the forward electric cylinder force is 0, then the reverse electric cylinder force is equal to the difference between the reverse electric cylinder force at the previous moment and the deviation value obtained by looking up the desired gear position and angular velocity table, and the reverse electric cylinder force is not greater than 0.

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