Dynamic repair control method for gear-in failure of electric drive axle

Abstract

The invention relates to the technical field of electric drive axle gear shifting control, in particular to a dynamic repair control method for gear shifting failure of an electric drive axle, which comprises the following steps of: S1, monitoring a gear shifting state, and monitoring a target gear state and an actual gear state in real time; s2, gear shifting failure recognition is carried out, and corresponding time threshold values are set based on gear shifting stages divided by the gear shifting process; s3, confirming the number of times of continuous gear shifting failures, and identifying and counting the continuous gear shifting failures; s4, judging the severity level of the continuous gear-shifting failure, and formulating a judgment standard of the severity level of the continuous gear-shifting failure; and S5, carrying out dynamic post-processing on the continuous gear-shifting failure, and establishing a post-processing mechanism of each severity level. According to the invention, the working condition compatibility and the overall gear shifting success rate of the gear shifting mechanism of the electric drive axle product in the actual application process of the whole vehicle are improved, and meanwhile, the gear shifting quality control and the gear shifting mechanism protection can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric drive axle shift control, in particular to a commercial vehicle electric drive axle abnormal condition under the repair control implementation scheme of the failure of the forward gear. BACKGROUND

[0002] With the rapid advancement of automobile electrification, the commercial vehicle industry is also actively seeking electrification. Under the impetus of the trend of automobile electrification, the application of electric drive axle products in the field of commercial vehicles has been rapidly popularized, and various powertrain manufacturers have increased their research and development efforts on electric drive axle products. Although the high-efficiency drive speed range of the motor has been greatly improved compared to the traditional engine, due to the particularity of the large variation of the actual use condition and load of commercial vehicles, it is still necessary to retain the necessary gear.

[0003] In the prior art, there is a processing scheme for static continuous gear failure, which adjusts the rotation state of the shift motor by closed-loop control to achieve precise adjustment of the rotation state of the shift motor by increasing the target torque in stages and dynamically correcting the drive duty cycle of the shift motor. If the three retries fail, the safety state is triggered, the power output is cut off, and a fault alarm is triggered. However, this method has some limitations. On the one hand, although the target torque is increased in stages to compensate for the speed difference to some extent, it cannot guarantee the rationality of the speed regulation result, and the torque fluctuation during the shift process may cause uncontrollable vehicle feeling; on the other hand, the gradient of the dynamic correction of the shift motor drive is too large, although it can exclude the failure of the forward gear due to insufficient shift force, but multiple high-torque impacts may increase the wear rate of the synchronizer tooth surface, and it is not friendly to the shift mechanism and the shift motor.

[0004] The prior art has problems such as insufficient speed regulation accuracy, uncontrollable vehicle feeling, and insufficient protection of the shift mechanism and the motor when dealing with continuous gear failure of the electric drive axle. This indicates the need for a more effective, gentler, and friendly dynamic repair control scheme for the shift mechanism to improve the shift success rate and reliability of the electric drive axle product under extreme conditions, while also considering shift quality and mechanism protection. SUMMARY

[0005] The purpose of the present application is to provide a dynamic repair control scheme for continuous gear failure under abnormal conditions of an electric drive axle, to improve the compatibility of the shift mechanism and the overall shift success rate of the electric drive axle product in the actual application process of the vehicle, while also being able to control the shift quality and protect the shift mechanism.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present application provides an electric drive axle gear failure dynamic repair control method, comprising the following steps: Step S1, shift state monitoring is performed, the target gear position and the actual gear state are monitored in real time, if the target gear monitoring value changes, it is judged that there is a shift demand, if the target gear monitoring value and the actual gear monitoring value are the same and not in the shift process, it is judged that there is no shift demand; Step S2, shift failure identification is performed, based on the shift stage setting of the shift process division, the corresponding time threshold value is set, if the shift stage execution time exceeds the corresponding time threshold value, it is judged as timeout failure; Step S3, the number of consecutive upshift failures is confirmed, according to the shift failure identification in step S2, the consecutive upshift failure identification and counting are performed; Step S4, the severity level of consecutive upshift failure is judged, according to the number of consecutive upshift failures in step S3, the severity level of consecutive upshift failure is determined; Step S5, the dynamic post-processing of consecutive upshift failure is performed, according to the severity level of consecutive upshift failure in step S4, the post-processing mechanism of each severity level is established.

[0007] Preferably, in step S2, the shift stage includes disengagement, speed regulation in neutral and upshift, and the upshift stage is further divided into Gap empty stroke segment, Fric sliding film segment and Enter into gear segment.

[0008] Preferably, in step S2, after each upshift failure is identified, the shift fork is controlled to return to N position again, the main drive motor shift speed regulation is performed again, and the upshift is tried again after the speed regulation is completed.

[0009] Preferably, in step S3, the counting zero mechanism is set, when the upshift success is identified or the current driving cycle is ended, the number of consecutive upshift failures is zero.

[0010] Preferably, in step S5, the post-processing mechanism includes speed difference compensation of speed regulation, speed difference compensation of upshift and shift motor drive compensation, the values of speed difference compensation of speed regulation, speed difference compensation of upshift and shift motor drive compensation increase with the increase of the severity level of consecutive upshift failure.

[0011] Preferably, in step S5, if the severity level of consecutive upshift failure reaches severe, and the shift attempt fails for 5 times in succession, the shift failure is diagnosed, and the shift attempt is stopped.

[0012] Preferably, the shift speed difference is the shift sleeve end and the shift tooth speed difference, that is, the main drive motor output shaft end is converted to the shift fork sleeve end speed minus the output shaft end converted to the shift tooth hub end speed according to the speed ratio.

[0013] Preferably, the shift motor drive compensation value is the percentage increase based on the basic shift force.

[0014] Preferably, the shift motor driving duty cycle strategy is only applicable to the upshift slip film stage.

[0015] Preferably, in step S5, the upshift speed difference compensation adopts a pulse speed regulation mode, and is assisted by main drive motor torque protection.

[0016] In summary, the present application includes the following beneficial technical effects: The present application significantly improves the stability and reliability of shift control through the continuous upshift failure speed difference compensation post-processing strategy. This strategy can meet the upshift speed difference demand under normal conditions, while effectively improving the robustness of shift control under extreme working conditions, thereby improving the success rate of shift. Specifically, through speed difference compensation, the system can adjust the speed difference during the shift process according to different severity levels to ensure sufficient speed difference during the shift process, thereby avoiding upshift failure due to insufficient speed difference. This dynamic adjustment mechanism not only improves the success rate of shift, but also enhances the adaptability of the electric drive axle product under complex working conditions, making the shift process more stable and reliable.

[0017] The upshift speed difference compensation strategy of the present application further improves the speed difference compensation accuracy in the upshift process, effectively reducing the uncertainty of the speed regulation result of the transmission system. Through accurate speed difference compensation control, the system can more accurately adjust the speed difference between the shift sleeve and the shift hub, making the upshift process more stable and accurate. This high degree of accuracy and stability not only reduces the impact and vibration during the shift process, but also significantly improves the shift quality. By reducing the uncertainty of the speed regulation result, the system can achieve more consistent shift performance under various working conditions, thereby improving the overall success rate of shift and improving the driving experience.

[0018] In addition, the continuous upshift failure shift motor driving post-processing strategy of the present application improves the success rate of shift while providing more friendly protection for the shift motor and shift mechanism. By reasonably adjusting the driving force of the shift motor, the system can reduce the wear of the shift motor and shift mechanism while ensuring the success of the shift, thereby prolonging its service life. Specifically, the shift motor driving compensation mechanism moderately increases the driving force according to the severity level of continuous upshift failure to ensure sufficient force for upshift, while avoiding unnecessary overdrive, thereby reducing the load of the shift motor and shift mechanism. This intelligent adjustment of the driving strategy not only improves the success rate of shift, but also helps to maintain the long-term stability and reliability of the shift mechanism, reduces maintenance requirements and equipment wear, and reduces long-term operating costs. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The present application is an electric drive axle continuous upshift failure post-processing control flowchart for the electric drive axle upshift failure dynamic repair control method. Figure 2A continuous gear progression failure severity level division chart of the electric drive axle in the control method for dynamically repairing the gear progression failure of the electric drive axle is provided in the control method for dynamically repairing the gear progression failure of the electric drive axle. Figure 3 A post-processing mechanism chart of the electric drive axle after continuous gear progression failure is provided in the control method for dynamically repairing the gear progression failure of the electric drive axle. Figure 4 A gear position design chart of the electric drive axle is provided in the control method for dynamically repairing the gear progression failure of the electric drive axle. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0021] Embodiment 1: The embodiments of the present application disclose a dynamic repair control scheme after continuous gear progression failure of an electric drive axle under extreme working conditions, aiming to improve the extreme working condition compatibility of the gear shifting mechanism and the overall gear shifting success rate of the electric drive axle product in the actual application process of the vehicle, while being able to control the gear shifting quality and protect the gear shifting mechanism. The present application comprises the following steps: S1, gear shifting state monitoring.

[0022] This is the starting step of the entire control scheme, and the core is to monitor the gear shifting state in real time to obtain the gear shifting demand in time. Specifically, this step monitors the target gear position and the actual gear position state in real time. If the target gear position monitoring value changes, for example, from N to 1, 1 to 2, 2 to 3, or from 3 to 2, 2 to 1, 1 to N, etc., it is judged that there is a gear shifting demand. On the contrary, if the target gear position monitoring value is the same as the actual gear position monitoring value, and the current is not in the gear shifting process, it is judged that there is no gear shifting demand. This monitoring step is crucial for timely responding to the gear shifting request and is the basis for subsequent gear shifting operation.

[0023] S2, gear shifting failure identification.

[0024] This is a key step in the control scheme, and its role is to establish a judgment mechanism for gear shifting failure. According to the different gear shifting stages (emptying, emptying speed regulation, gear progression) divided by the gear shifting process, specific time thresholds are set. If the execution time of a specific gear shifting stage exceeds the preset time threshold, it is diagnosed as a timeout failure.

[0025] Further, the engagement stage is divided into Gap gap section (shift fork clearance between the shift dog tooth surface), Fric sliding film section (shift control allowed range for easy shift control near the top tooth point) and Enter engagement section (shift dog tooth point to shift target position) according to the structural characteristics of the shift mechanism. Each stage is divided according to the design shift travel and shift fork displacement sensor signal of different gears, and the actual threshold value allowed to execute is set for failure judgment. In addition, this step also establishes the judgment standard of continuous engagement failure, that is, as long as it is diagnosed as failure at any stage in the shift process, it is judged that the shift fails. In particular, after each failure of the engagement is identified, the shift fork needs to be controlled to return to the N position, and the main drive motor shift speed regulation is performed again. After the speed regulation is completed, the engagement is tried again. Such design helps to take measures quickly after the shift fails, and creates conditions for subsequent shift attempts.

[0026] S3, continuous engagement failure number confirmation.

[0027] In this step, according to the shift failure judgment mechanism in step S2, the identification and counting of continuous engagement failure are performed. When the engagement failure is identified, the number of continuous engagement failures is accumulated. For example, if the actual gear position does not reach the target gear position before the target gear position changes, the first time the engagement failure is identified, the number of continuous engagement failures n = 1; if the engagement failure is identified again, the number n = 1 + 1; if the engagement failure is identified again, the number of continuous engagement failures n = 1 + 1 + 1... and so on. At the same time, a counting zero mechanism is set, that is, when the engagement is successful (the actual gear position is equal to the target gear position) or the current driving cycle is ended, the number of continuous engagement failures is zero. This mechanism helps to dynamically track the continuous engagement failure, and provides accurate data support for subsequent severity level judgment.

[0028] S4, continuous engagement failure severity level judgment.

[0029] In this step, according to the number of continuous engagement failures in step S3, the continuous engagement failure severity level judgment standard is formulated. Specifically, a continuous engagement failure severity level evaluation mechanism is established, and the continuous engagement failure is 1 time for light, 2 times for medium low, 3 times for medium, 4 times for medium high, and 5 times for heavy. In this way, the continuous engagement failure can be classified, thereby providing a basis for subsequent dynamic post-processing. This judgment standard helps to quantify the degree of continuous engagement failure, so that the subsequent processing measures are more targeted.

[0030] S5, continuous engagement failure dynamic post-processing.

[0031] This is the final step of the control scheme, which is based on the classification of the severity level of the continuous upshift failure. Specifically, for different severity levels, the corresponding post-processing mechanism is established. For example, for mild failure, the speed difference compensation is ± 10 rpm, the upshift speed difference compensation is ± 5 rpm, and the shift motor drive compensation is ± 5%; while for severe failure, the corresponding compensation values are increased to ± 30 rpm, ± 30 rpm and ± 50%.

[0032] In addition, this step also involves the adjustment of the shift speed difference, upshift speed difference compensation and shift motor driving force. For example, when the upshift speed difference is identified to be less than the speed difference allowed range during the upshift process, the upshift speed difference compensation intervention strategy is started, and the main drive motor torque protection is supplemented by pulse speed regulation to prevent upshift failure. The shift motor driving force is moderately increased with the increase of the severity level of the continuous upshift failure to provide upshift force guarantee. In particular, if the severity level of the continuous upshift failure reaches severe, and the continuous 5 shift attempts fail, the shift failure is diagnosed, and the continuous shift attempt is stopped to protect the shift motor and the shift mechanism.

[0033] The dynamic repair control scheme for continuous upshift failure under extreme working conditions of the electric drive axle proposed in the embodiment of the present application can effectively improve the shift success rate of the electric drive axle product in the actual application of the vehicle, while taking into account the shift quality control and the shift mechanism protection. The scheme fully considers the continuous upshift failure of different severity levels and takes corresponding dynamic post-processing measures to ensure the reliability and durability of the electric drive axle under extreme working conditions.

[0034] The dynamic repair control scheme for continuous upshift failure under extreme working conditions of the electric drive axle of the embodiment of the present application effectively improves the shift performance and reliability of the electric drive axle under complex working conditions through fine monitoring and management of the shift process.

[0035] Embodiment 2: This embodiment is based on embodiment 1, in order to make the personnel in this technical field better understand the scheme of the present application, the following will be further explained in detail in combination with the drawings: In the shift state monitoring stage of step S1, the 6 key gear positions (N0, G1, N1, G2, N2, G3) of the 3rd gear spiral shift mechanism of the SQ350 electric drive axle are monitored in real time. Among them, N is the nominal empty gear position of the shift control, N0 is the 1st empty gear position of the S350 electric drive axle shift mechanism, G1 is the 1st gear position of the S350 electric drive axle shift mechanism, N1 is the 2nd empty gear position of the S350 electric drive axle shift mechanism, G2 is the 2nd gear position of the S350 electric drive axle shift mechanism, N2 is the 3rd empty gear position of the S350 electric drive axle shift mechanism, and G3 is the 3rd gear position of the S350 electric drive axle shift mechanism.

[0036] The monitoring of these gear positions ensures that any changes between the target gear position and the actual gear position can be captured in a timely manner. When the target gear position monitoring value changes, it is quickly determined that there is a shift demand, thereby triggering the subsequent shift operation process. This real-time monitoring mechanism is the basis for ensuring the timeliness and accuracy of the shift, and provides the necessary premise for the effective implementation of the entire control scheme.

[0037] In the shift failure identification stage of step S2, according to the different stages of the shift process (emptying, emptying speed regulation, and gear engaging) and the subdivided Gap empty stroke stage, Fric sliding film stage, and Enter gear engaging stage, specific time thresholds are set for each stage. If the execution time of a specific shift stage exceeds the preset time threshold, it is diagnosed as a timeout failure. For example, the execution time for emptying is 300ms, the execution time for speed regulation is 400ms, and the execution time for gear engaging is also 400ms. Once the execution time of a stage exceeds the set threshold, it is immediately diagnosed as a timeout failure. This failure judgment mechanism based on time threshold can timely identify abnormal situations in the shift process, and provide timely feedback for subsequent shift repair measures. At the same time, after identifying a gear engaging failure each time, the shift fork is controlled to return to the N gear position and the shift speed regulation is performed again. This measure helps to quickly recover to a stable state after a shift failure, creating conditions for the next shift attempt. The overall design of the shift fork moves in the order of N0->G1->N1->G2->N2->G3->N2->G2->N1->G1->N0.

[0038] In the continuous gear engaging failure number confirmation stage of step S3, the shift failure conditions are counted and tracked. Each time a shift failure is identified, the counter is incremented by 1 to accumulate the number of consecutive gear engaging failures. At the same time, a zeroing mechanism is provided, which resets the count when the shift is successful or the driving cycle ends. This mechanism ensures that the continuous gear engaging failure conditions can be dynamically tracked and reset at appropriate times to avoid unnecessary cumulative effects. In this way, the number of consecutive gear engaging failures can be accurately recorded to provide reliable data support for subsequent severity level judgment.

[0039] In the step S4, the severity level of the continuous failure of the gear engagement is determined according to the accumulated number of failures. Specifically, 1 failure is mild, 2 failures are low, 3 failures are moderate, 4 failures are high, and 5 failures are severe. This evaluation criterion quantifies the continuous failure of the gear engagement into different levels, so that the subsequent processing measures can be responded to according to the severity. For example, in the case of mild failure, a relatively mild compensation measure can be taken, while in the case of severe failure, a more aggressive strategy can be taken, or even the gear shifting attempt can be stopped to protect the gear shifting mechanism.

[0040] In the step S5, the corresponding post-processing measures are taken according to the severity level defined in step S4. These measures include speed difference compensation, gear engagement speed difference compensation, and gear motor driving compensation. For example, for the case of moderate failure, the speed difference compensation is -15 rpm, the gear engagement speed difference compensation is -10 rpm, and the gear motor driving compensation is +10%, which aims to improve the success rate of gear shifting by adjusting the key parameters in the gear shifting process. In particular, the gear engagement speed difference compensation adopts a pulse speed regulation mode, and is assisted by the main drive motor torque protection, which not only improves the accuracy of the speed regulation, but also avoids the unexpected power impact caused by excessive torque. In addition, the appropriate increase of the driving force of the gear motor provides sufficient power for the gear engagement, which helps to overcome the gear engagement resistance in abnormal working conditions. For the case of severe failure, after 5 consecutive gear shifting attempts fail, the gear shifting failure is diagnosed and the gear shifting attempt is stopped to protect the gear motor and the gear shifting mechanism from further damage.

[0041] The gear shifting speed difference in the present application is the speed difference between the gear shifting sleeve end and the gear shifting tooth, i.e. the speed of the output shaft end converted according to the speed ratio to the gear shifting sleeve end minus the speed of the output shaft end converted according to the speed ratio to the gear shifting hub end (ΔS=S mot -S Outspd ). The sign of the speed difference depends on the acceleration direction of the vehicle. If the vehicle is accelerating, the sign of the gear shifting speed difference is negative, and the sign of the speed difference compensation is also negative. Conversely, if the vehicle is decelerating, the sign of the gear shifting speed difference is positive, and the sign of the speed difference compensation is also negative. By taking full advantage of the characteristics of the large inertia of the vehicle wheel end and the small inertia of the motor end, the speed difference over 0 point during the gear engagement is avoided as much as possible, so as to ensure that the gear engagement has sufficient speed difference.

[0042] According to the step 2, the gear shifting fails to attempt mechanism, each time the gear shifting fails to re-empty the gear shifting speed regulation. The speed difference is increased moderately with the continuous gear shifting failure severity level, which aims to provide the speed difference guarantee and eliminate the gear shifting failure caused by the insufficient speed difference. Secondly, the moderate increase of the gear shifting speed difference helps to improve the low speed regulation caused by the inaccurate speed sensor, which leads to the low speed of the output shaft and the speed sensor output value may be 0, such as the output shaft speed is lower than 3 rpm, and the speed sensor identification value is 0.

[0043] The gear shifting speed difference compensation is started when the gear shifting speed difference is less than the speed difference allowable range in the gear shifting process, which aims to prevent the gear shifting failure caused by the small gear shifting speed difference due to the increasing top tooth force in the gear shifting process, and further improves the gear shifting success rate. The innovation of the gear shifting speed difference compensation is to use the pulse speed regulation method, supplemented by the main drive motor torque protection. This method can regulate the speed more accurately compared with the traditional torque intervention method, and prevent the unexpected power impact on the vehicle caused by the excessive torque in the gear shifting process. The gear shifting motor driving force is increased moderately with the continuous gear shifting failure severity level, which aims to provide the gear shifting force guarantee and eliminate the gear shifting failure caused by the insufficient gear shifting force in the abnormal working condition. The gear shifting motor driving compensation value of the present application is the percentage increase based on the basic gear shifting force, such as the basic gear shifting driving duty cycle is 50% at the top tooth point sliding film stage, the gear shifting motor driving needs to be increased by 5% based on the 50% driving duty cycle after the light gear shifting failure, that is, the comprehensive gear shifting driving is increased to 55%.

[0044] The gear shifting motor driving symbol and the continuous gear shifting failure gear shifting driving sliding film compensation symbol described in the present application depend on the gear shifting mechanism and the gear position design. The present application refers to the characteristics of the 3-gear gear shifting mechanism of the existing SQ350 electric drive bridge product, and the gear shifting motor driving symbol is positive from the low gear position to the high gear position, and the gear shifting motor driving symbol is negative from the high gear position to the low gear position (SQ350 is a type of electric drive bridge).

[0045] In particular, the shift motor drive duty cycle strategy of the present application is only applicable to the forward gear sliding film stage, and is not applicable to other shift stages. The shift motor drive control scheme proposed in the present application has both strength and intensity. In the moderate and below severity level of continuous forward gear failure, the shift motor drive control is as gentle as possible. The early stage will not cause significant increase in shift impact due to additional intervention. The maximum limit is to reduce the problems such as severe wear of the shift fork caused by excessive shift force. And it also has the strength of shift force. In the continuous forward gear failure level higher than moderate, in order to achieve the purpose of forward gear, a certain degree of forward gear comfort is reduced, the shift motor drive is increased as much as possible to overcome the forward gear resistance required by abnormal working condition shift, and the forward gear force is sufficient. This strategy can bring the effect of control of both strength and flexibility. If the severity level of continuous forward gear failure reaches severe, and the shift attempt fails for 5 times in a row, it is diagnosed as a shift failure. In order to further protect the shift motor and the shift mechanism, it is necessary to stop the shift attempt.

[0046] Through the close cooperation and orderly execution of each stage, the control scheme of the embodiment of the present application can effectively cope with the problem of continuous forward gear failure that may occur in the electric drive axle under extreme working conditions. The scheme not only improves the success rate of shift, but also takes into account the quality of shift and the protection of mechanism, and has significant technical effect and practical application value.

[0047] Finally, it should be noted that: the above only describes the preferred embodiments of the present application, and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. An electric drive bridge failure dynamic repair control method, characterized in that, The method comprises the following steps: Step S1, shift state monitoring is performed, the target gear position and the actual gear state are monitored in real time, if the target gear monitoring value changes, it is judged that there is a shift demand, if the target gear monitoring value and the actual gear monitoring value are the same and not in the shift process, it is judged that there is no shift demand; Step S2, shift failure identification is performed, corresponding time thresholds are set based on the shift stage division, if the shift stage execution time exceeds the corresponding time threshold, it is judged as a timeout failure; Step S3, the number of consecutive upshift failures is confirmed, according to the shift failure identification in step S2, the consecutive upshift failure identification and counting are performed; Step S4, the severity level of consecutive upshift failure is judged, according to the number of consecutive upshift failures in step S3, the severity level judgment standard of consecutive upshift failure is formulated; Step S5, dynamic post-processing of consecutive upshift failure is performed, according to the severity level of consecutive upshift failure in step S4, the post-processing mechanism of each severity level is established.

2. The control method according to claim 1, wherein In step S2, the shift stage includes disengagement, neutral speed regulation and upshift, and the upshift stage is further divided into Gap empty stroke segment, Fric slip film segment and Enter into gear segment.

3. The control method according to claim 2, wherein In step S2, after identifying the upshift failure each time, the shift fork is controlled to return to the N position, the main drive motor shift speed regulation is performed again, and the upshift is tried again after the speed regulation is completed.

4. The control method according to claim 1, wherein In step S3, the counting zero mechanism is set, when the upshift attempt is successful or the current driving cycle is ended, the number of consecutive upshift failures is zeroed.

5. The control method of claim 1, wherein, In step S5, the post-processing mechanism includes speed difference compensation for speed regulation, upshift speed difference compensation and shift motor drive compensation, the values of speed difference compensation for speed regulation, upshift speed difference compensation and shift motor drive compensation increase with the increase of the severity level of consecutive upshift failure.

6. The control method according to claim 5, wherein In step S5, if the severity level of consecutive upshift failure reaches severe, and the shift attempt fails for 5 times in succession, the shift failure is diagnosed, and the shift attempt is stopped.

7. The control method according to claim 6, wherein The shift speed difference is the speed difference between the shift sleeve end and the shift tooth, that is, the speed of the main drive motor output shaft end converted to the shift fork sleeve end according to the speed ratio minus the speed of the output shaft end converted to the shift tooth hub end according to the speed ratio.

8. The control method according to claim 7, wherein The shift motor drive compensation value is the percentage increase based on the basic shift force.

9. The control method according to claim 8, wherein The shift motor drive duty cycle strategy is only applicable to the upshift slip film stage.

10. The control method according to claim 9, wherein In step S5, the upshift speed difference compensation adopts pulse speed regulation mode, and is assisted by main drive motor torque protection.

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