A shift control method and system of a two-gear electrically-controlled AMT without clutch
By constructing a multi-objective optimization function and a multi-objective optimization algorithm, the problem of balancing smoothness and speed during gear shifting in a clutchless AMT was solved. Optimized timing control commands were generated, improving the smoothness and speed of the gear shifting process, avoiding synchronizer failure, and enhancing overall vehicle performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DONGFENG AUTOMOBILE COMPANY
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-12
AI Technical Summary
Clutchless AMTs struggle to balance smoothness and speed during gear shifts, which can easily lead to synchronizer mechanical failures.
A multi-objective optimization function incorporating shift smoothness and shift time is constructed, and a multi-objective optimization algorithm is used to solve it, generating a Pareto optimal solution set. The optimal solution is then selected based on the vehicle's performance positioning to generate timing control commands for the motor and synchronizer.
It achieves a balance between smoothness and speed during gear shifting, avoids synchronizer gear wear and mechanical wear, and improves the overall driving comfort and power response of the vehicle.
Smart Images
Figure CN122191290A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of new energy vehicle power system technology, and in particular to a shift control method and system for a two-speed electronically controlled clutchless AMT. Background Technology
[0002] With the rapid development of the new energy vehicle industry, two-speed AMT has become one of the mainstream transmission solutions for pure electric and hybrid vehicles because it can match the wide speed range of the motor and improve the power and economy of the whole vehicle. In order to reduce costs and simplify the structure, clutchless two-speed AMT has gradually replaced the traditional clutch structure. Its shifting process relies on the coordinated control of the electronic control synchronizer and the power source, without the need for the disengagement and engagement of the clutch.
[0003] However, precisely because the slippage buffering effect of the traditional clutch is eliminated, the coupling contradiction between shift smoothness and shift time becomes particularly prominent. Specifically: if an aggressive control strategy is adopted to pursue shorter shift times, such as significantly increasing the torque adjustment rate of the power source and increasing the shifting force of the synchronizer, although the power interruption time can be shortened, it is very easy for the longitudinal impact of the vehicle during the shift process to exceed the human comfort threshold due to the system's excessively rapid dynamic response and violent inertial shock, resulting in obvious jerking and discomfort, seriously affecting the driving experience. Conversely, if a conservative control strategy is adopted to focus on improving shift smoothness, such as excessively reducing the torque adjustment rate and delaying the synchronizer's action, although the shock can be suppressed, it will inevitably lead to a significant increase in the total shift time, weakening the vehicle's power response agility and failing to meet users' expectations for the instantaneous torque response of electric vehicles. The above-mentioned unreasonable parameter matching not only affects performance but also easily causes mechanical failures such as gear grinding, abnormal wear, or even jamming of the synchronizer when it engages due to excessive speed difference in actual working conditions, thereby reducing the working reliability and service life of the synchronizer and even the entire transmission system. Summary of the Invention
[0004] This application provides a shift control method and system for a two-speed electronically controlled clutchless AMT to solve the problem in related technologies that it is difficult to balance smoothness and speed during shifting in a clutchless two-speed AMT, and that it is easy to cause mechanical failure of the synchronizer.
[0005] Firstly, a shift control method for a two-speed electronically controlled clutchless automatic manual transmission (AMT) is provided, comprising: Determine the current shifting condition based on vehicle operating parameters; Construct an optimization function, which includes a shift smoothness objective function and a shift time objective function. The input parameters of the optimization function include a set of optimization variables corresponding to the shift condition. A multi-objective optimization algorithm is used to solve the optimization function under the constraints, and the optimal solution set is obtained, which consists of multiple sets of objective function values for shift smoothness and objective function values for shift time. Select a set of optimal optimization variables from the set of optimal solutions; Based on the values of each optimization variable in the optimal set of optimization variables, control commands are output to the power source and synchronizer according to a preset timing sequence.
[0006] In some embodiments, the shift smoothness objective function is calculated as follows: Calculate the ratios of the maximum impact, net torque fluctuation amplitude, and input shaft speed fluctuation amplitude to their respective preset reference thresholds; Multiply the three ratios by the preset impact weighting coefficient, torque fluctuation weighting coefficient, and input shaft speed fluctuation weighting coefficient respectively, and then add them together; The sum of the three weighting coefficients is 1.
[0007] In some embodiments, the impact weighting coefficient is configured according to the vehicle performance positioning: For comfort-oriented models, the configuration is greater than or equal to the first threshold. For sporty models, the configuration is less than or equal to the second threshold; The first threshold is greater than the second threshold.
[0008] In some embodiments, the shifting conditions include upshifting and downshifting. The set of optimization variables corresponding to the shifting condition includes: Under upshifting conditions, the set of optimized variables includes the power source torque unloading rate, torque recovery rate, synchronizer shifting force, and synchronizer start-up timing. In downshifting mode, the set of optimized variables, in addition to the optimized variables included in upshifting mode, also includes the input shaft speed adjustment rate.
[0009] In some embodiments, the constraints include at least: The speed difference when the synchronizers are engaged is less than or equal to a preset speed difference threshold. The torque interruption time is less than or equal to the preset torque interruption time threshold. The synchronizer shift force is less than or equal to the preset shift force threshold. The values of the power source torque unloading rate and torque recovery rate are within the preset torque adjustment rate range; In the downshifting operation, the input shaft speed adjustment rate is also within the preset speed adjustment rate range.
[0010] In some embodiments, a multi-objective optimization algorithm is employed to solve the optimization function under the given constraints, including the following steps: Initialize the population, where each individual in the population is a combination of values from the set of optimization variables; Calculate the objective function value for each individual in the population; Perform non-dominated sorting of individuals in the population and calculate crowding distance; Based on the non-dominated sorting structure and crowding distance, the next generation population is generated through selection, crossover, and mutation operations. Repeat the above steps until the maximum number of iterations is reached, then output the optimal solution set.
[0011] In some embodiments, selecting an optimal set of optimization variables from the optimal solution set includes: For comfort models, the solution to the objective function of minimizing ride comfort is chosen, while for sport models, the solution to the objective function of minimizing shift time is chosen.
[0012] In some embodiments, the preset timing is: the synchronizer start-up action begins within a preset time after the power source torque is unloaded to the target torque.
[0013] In some embodiments, based on the values of each optimization variable in the optimal set of optimization variables, control commands are output to the power source and synchronizer according to a preset timing sequence, including: If the current operation is upshifting, the control commands include: the power source unloads torque at the torque unloading rate, delays the synchronizer start-up sequence, the electronically controlled synchronizer applies shifting force according to the synchronizer shifting force, and the power source restores torque at the torque recovery rate. If the current operation is downshifting, the control commands include: the power source unloads torque at the torque unloading rate, adjusts the speed at the speed adjustment rate, delays the synchronizer start-up sequence, the electronically controlled synchronizer applies shifting force according to the synchronizer shifting force, and the power source restores torque at the torque recovery rate.
[0014] Secondly, a shift control system for a two-speed electronically controlled clutchless automatic manual transmission (AMT) is provided, characterized in that it includes: The judgment module is used to determine the current shifting condition based on vehicle operating parameters; A construction module is used to construct an optimization function, which includes a shift smoothness objective function and a shift time objective function. The input parameters of the optimization function include a set of optimization variables corresponding to the shift condition. The calculation module is used to solve the optimization function under the constraint conditions using a multi-objective optimization algorithm to obtain the optimal solution set consisting of multiple sets of shift smoothness objective function values and shift time objective function values; A filtering module is used to filter a set of optimal optimization variables from the set of optimal solutions; The control module is used to output control commands to the power source and synchronizer according to a preset timing sequence based on the values of each optimization variable in the optimal set of optimization variables.
[0015] This application provides a shift control method and system for a two-speed electronically controlled clutchless AMT. By constructing a multi-objective optimization function that includes two conflicting objectives—shift smoothness and shift time—and introducing a multi-objective optimization algorithm to solve it, the trade-off between smoothness and speed is transformed into an optimization problem of finding the Pareto optimal solution set. Based on this, the system autonomously selects the optimal solution that matches the vehicle's performance positioning from the optimal solution set, rather than relying on a single fixed parameter or empirical tuning. Finally, the optimized combination of variables is transformed into timing control commands for the motor and synchronizer. This mechanism ensures that the shifting process can actively control the impact to guarantee smoothness while reasonably compressing the shift time to guarantee power response. Simultaneously, by setting constraints, the risks of synchronizer gear wear and mechanical damage caused by excessive speed differences or excessive torque adjustment are avoided. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 A flowchart of a shift control method for a two-speed electronically controlled clutchless AMT provided in an embodiment of this application; Figure 2 This is a block diagram of the shift control system of a two-speed electronically controlled clutchless AMT provided in an embodiment of this application. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0019] The clutchless structure lacks the slippage buffering effect of a clutch, making the coupling contradiction between shift smoothness and shift time particularly prominent: if the goal is to shorten the shift time, the torque adjustment rate and synchronizer shift force need to be increased, but this can easily lead to excessive shock and a noticeable jerking sensation; if the focus is on smoothness, reducing the torque adjustment rate will prolong the shift time and affect the power response.
[0020] Existing AMT shifting optimization technologies are mostly designed for clutch-equipped structures. The optimization function needs to take into account parameters such as clutch pressure and slippage work, which cannot adapt to the unique characteristics of clutchless structures. At the same time, existing optimization schemes for clutchless AMTs mostly adopt single-objective optimization or generalized multi-objective optimization, without fine-tuning the upshifting and downshifting conditions of two-speed structures. This results in unreasonable timing matching and problems such as synchronizer tooth wear or excessive impact.
[0021] This application provides a shift control method for a two-speed electronically controlled clutchless AMT, which can solve the problem in related technologies that it is difficult to balance smoothness and speed during shifting in a clutchless two-speed AMT, and that it is easy to cause mechanical failure of the synchronizer.
[0022] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.
[0023] TCU: Automatic Transmission Control Unit; AMT: Mechanical Automatic Transmission; NSGA-II: A non-dominated sorting genetic algorithm with an elitist strategy.
[0024] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0025] In a first aspect, this application provides a shift control method for a two-speed electronically controlled clutchless automatic transmission (AMT), comprising the following steps: S100: Determines the current shifting condition based on vehicle operating parameters.
[0026] The system acquires real-time vehicle operating parameters, including vehicle speed signals obtained through wheel speed sensors, motor speed signals obtained through motor encoders, throttle opening signals obtained through accelerator pedal position sensors, battery SOC status obtained through the BMS system, and current gear status obtained through gear position sensors.
[0027] Based on the vehicle's real-time operating parameters, the current gear shift condition is determined to be either upshifting (1→2) or downshifting (2→1). The conditions for upshifting are: the motor speed reaches the upper limit of the efficient operating range (e.g., 8000 r / min) or the vehicle speed reaches the preset upshift threshold (e.g., 60 km / h); the conditions for downshifting are: the motor speed is below the lower limit of the efficient operating range (e.g., 2000 r / min) or the throttle opening is greater than the preset power demand threshold (e.g., 80%).
[0028] The high-efficiency operating range is preset in the TCU, usually the peak efficiency range of the motor (e.g., 2000-8000r / min). The preset upshift threshold is set according to the vehicle characteristics, such as 60km / h.
[0029] By fusing multi-source sensor data and intelligently identifying operating conditions, accurate identification of shifting conditions is achieved, providing a foundation for subsequent optimization of the differentiated configuration of variable sets, avoiding control strategy mismatch caused by misjudgment of operating conditions, and improving the scenario adaptability of shifting control.
[0030] S200: Construct an optimization function, which includes a shift smoothness objective function and a shift time objective function. The input parameters of the optimization function include a set of optimization variables corresponding to the shift condition.
[0031] Construct an optimization function with shift smoothness and shift time as dual objectives.
[0032] S201: Construct the objective function for shift smoothness.
[0033] The objective function for shift smoothness is calculated as follows: Calculate the ratios of the maximum impact, net torque fluctuation amplitude, and input shaft speed fluctuation amplitude to their respective preset reference thresholds. The maximum impact is the maximum value of the rate of change of acceleration during the gear shift; the net torque fluctuation amplitude is the difference between the maximum and minimum values of the actual output torque on the drive wheels during the gear shift; and the input shaft speed fluctuation amplitude is the difference between the maximum and minimum values of the input shaft speed of the gearbox during the gear shift.
[0034] Multiply the three ratios by the preset impact weighting coefficient, torque fluctuation weighting coefficient, and input shaft speed fluctuation weighting coefficient respectively, and then add them together; The sum of the three weighting coefficients is 1.
[0035] Specifically, the mathematical expression for the objective function of shift smoothness is: ; In the formula, X is the set of optimization variables; J represents the impact force, T represents the torque, and n represents the input shaft speed. This is the impact weighting coefficient. This is the torque fluctuation weighting coefficient. This is the input shaft speed fluctuation weighting coefficient, and + + =1; For maximum impact, This refers to the net torque fluctuation amplitude of the drive wheels. This refers to the amplitude of the input shaft speed fluctuation. As the impact reference threshold, it takes the value of ≤8m / s 3 ; The reference threshold for torque fluctuation is set to a value of [value to be filled in]. ≤15% T rated , T rated The rated torque of the power source; The reference threshold for speed fluctuation is set to a value of ≤200r / min.
[0036] Among them, the impact weighting coefficient Based on the vehicle's performance positioning, the configuration for comfort models is greater than or equal to the first threshold. For sporty models, the configuration is less than or equal to the second threshold; The first threshold is greater than the second threshold, and both the first and second thresholds are values between 0 and 1.
[0037] In this embodiment, for comfort-type vehicles ≥0.6, for sports cars ≤0.4.
[0038] The 0.6 indicates that 60% of the focus is on smoothness and 40% on shift time and fluctuations. Comfort models prioritize a smooth ride, no jerking, and low impact, and shift speed can be compromised to a certain extent. The 0.4 indicates that 40% of the focus is on smoothness and 60% on shift speed. Sporty models accept slight impacts but are very sensitive to delays and power interruptions.
[0039] S202: Construct the objective function for shift time.
[0040] The objective function for shift time is expressed as follows: ; In the formula, This is the total shift time, including torque unloading time, speed synchronization time, shift execution time, and torque recovery time.
[0041] S203: Construct a set of optimization variables based on the operating conditions.
[0042] In the above objective functions for shift smoothness and shift time, the set of optimization variables X has different parameters under different operating conditions.
[0043] Under upshifting conditions, the set of optimized variables includes the power source torque unloading rate. Torque recovery rate Synchronizer shifting force and synchronizer startup sequence .
[0044] Under downshifting conditions, the set of optimized variables includes the power source torque unloading rate. Torque recovery rate Synchronizer shifting force Synchronizer startup sequence and speed regulation rate .
[0045] in, The target torque for unloading the power source is set to 5% to 15% of the rated torque of the power source, and not lower than the idle torque of the power source.
[0046] A comprehensive smoothness evaluation function is constructed, incorporating three dimensions: impact, torque fluctuation, and speed fluctuation, to fully characterize shift quality. Simultaneously, a shift time objective function is introduced, forming a typical multi-objective optimization problem with contradictions. Through vehicle-specific configurations with weighted coefficients, adaptive adaptation to different product positioning is achieved within the same algorithm framework. The condition-differentiated design of the optimization variable set fully considers the essential differences in dynamic characteristics during upshifting and downshifting, improving the relevance of the optimization problem.
[0047] S300: Using a multi-objective optimization algorithm, under the condition of satisfying the constraints, the optimization function is solved to obtain the optimal solution set consisting of multiple sets of shift smoothness objective function values and shift time objective function values.
[0048] S301: Define the constraints.
[0049] The constraints differ under different operating conditions. The constraints must include at least the following: The speed difference when the synchronizers are engaged is less than or equal to a preset speed difference threshold. The torque interruption time is less than or equal to the preset torque interruption time threshold. The synchronizer shift force is less than or equal to the preset shift force threshold. The values of the power source torque unloading rate and torque recovery rate are within the preset torque adjustment rate range; In the downshifting operation, the input shaft speed adjustment rate is also within the preset speed adjustment rate range.
[0050] Specifically, for the upshifting operation, the constraints include: Speed difference when synchronizer engaged ≤50r / min; Torque interruption time ≤0.2s; Synchronizer shift force ≤300N; 50 N·m / s ≤ Power source torque unloading rate ≤200 N·m / s; 50 N·m / s ≤ Torque recovery rate ≤200N·m / s.
[0051] For downshifting conditions, in addition to the constraints mentioned above, the following also applies: 500 r / min·s ≤ Input shaft speed adjustment rate ≤1500r / min·s.
[0052] The setting of constraints effectively avoids the risk of mechanical failures such as synchronizer tooth breakage and excessive torque impact, thus improving system reliability.
[0053] It should be noted that step S301 can be placed in step S100 or step S200, and there is no hard and fast rule.
[0054] S302: Solve the optimization function.
[0055] After the constraints are determined, the NSGA-II multi-objective optimization algorithm is used to solve the optimization function, obtaining the optimal solution set, i.e., the Pareto optimal solution set. Specifically, this includes: S3021: Initialize the population. The individuals in the population are combinations of values from the set of optimization variables X. Set the population size to 50~100, the maximum number of iterations to 100~200, the crossover probability to 0.8~0.9, and the mutation probability to 0.05~0.1. S3022: Calculate the objective function value for each individual in the population, i.e., the compliance objective function. and shift time objective function The value; S3023: Perform non-dominated ranking of individuals in the population and calculate the crowding distance for each individual; S3024: Based on the non-dominated sorting structure and crowding distance, the next generation population is generated through selection, crossover, and mutation operations; S3025: Repeat steps b~d until the maximum number of iterations is reached, output the non-dominated solutions in the current population, and form the optimal solution set.
[0056] Taking a simulation of a 120kW pure electric vehicle as an example, the population size is set to 100, the maximum number of iterations to 200, the crossover probability to 0.85, and the mutation probability to 0.08. After optimization calculations, a set of optimal solutions is obtained, containing 30 non-dominated solutions. Five typical optimization results are shown below:
[0057] By employing multi-objective optimization algorithms such as NSGA-II, the original experience-based parameter tuning problem is transformed into a mathematical optimization problem. Under the premise of satisfying mechanical constraints, smoothness and speed are systematically balanced. The generated optimal solution set provides a rich set of candidate solutions for subsequent vehicle model adaptation, avoiding the performance imbalance problem caused by traditional single-point optimization.
[0058] S400: Select a set of optimal optimization variables from the set of optimal solutions.
[0059] Based on the current vehicle model positioning (comfort / sport), target optimization parameters are selected from the set of optimal solutions. Specifically, for comfort models, the solution that minimizes the ride comfort objective function is selected, while for sport models, the solution that minimizes the shift time objective function is selected.
[0060] Taking the above optimal solution set as an example, if the current vehicle is a comfort model, then solution P01 is selected. The values of each optimization variable in the corresponding X optimization variable set are as follows: =75 N·m / s, =68 N·m / s, =145N, =0.062s, corresponding to a smoothness objective function value of 0.38 and a shift time objective function value of 0.36s. The measured impact force is 4.2m / s². 3 .
[0061] If the current vehicle is a sports model, then solution P05 is selected. The values of each optimization variable in the corresponding X optimization variable set are as follows: =185 N·m / s, =172 N·m / s, =289N, =0.025s, corresponding to a smoothness objective function value of 0.85 and a shift time objective function value of 0.2s. The measured impact force is 7.1m / s². 3 It still meets the comfort requirements.
[0062] By employing an adaptive vehicle positioning selection mechanism based on the optimal solution set, a product development model of "one algorithm, multiple adaptations" is achieved, significantly shortening the calibration cycle for different vehicle models. The selection strategy is directly linked to user experience needs (comfort / sport), ensuring that the final control parameters are highly aligned with the product positioning and improving user satisfaction.
[0063] S500: Based on the values of each optimized variable in the optimal set of optimized variables, control commands are output to the power source and synchronizer according to a preset timing sequence. Here, the power source refers to the motor.
[0064] Based on the selected target optimization parameters, the TCU outputs control commands to the power source and the electronic synchronizer, completing torque adjustment and synchronizer operation according to a preset timing sequence to achieve the gear shifting process. Synchronizer activation must occur within 0.02~0.1 seconds after the power source torque is unloaded to the target torque; the specific timing sequence is as follows: If the current operation is upshifting, the control command includes: according to the power source torque unloading rate. Unloading torque, delaying synchronizer startup timing The electronically controlled synchronizer operates according to the synchronizer's shifting force. Applying shift force to achieve synchronization, the power source recovers according to the torque recovery rate. Restore torque to target value; If the current operation is a downshift, the control command includes: according to the power source torque unloading rate. Unloading torque, the power source adjusts the rate according to the speed. Accelerate to target speed, delay synchronizer startup timing The electronically controlled synchronizer operates according to the synchronizer's shifting force. Applying shift force to achieve synchronization, the power source recovers according to the torque recovery rate. Restore torque to the target value.
[0065] The optimized parameter combination is transformed into precise timing control commands, realizing a complete closed loop from theoretical optimization results to actual control execution. The timing design fully considers the dynamic characteristics of the clutchless structure, and ensures smooth, fast, and reliable gear shifting through the coordinated control of torque, speed, and synchronizer. Differentiated timing designs for upshifting and downshifting precisely match the physical process requirements under different operating conditions, improving the level of control precision.
[0066] Secondly, this application provides a shift control system for a two-speed electronically controlled clutchless automatic manual transmission (AMT), comprising: The judgment module is used to determine the current shifting condition based on vehicle operating parameters; A construction module is used to construct an optimization function, which includes a shift smoothness objective function and a shift time objective function. The input parameters of the optimization function include a set of optimization variables corresponding to the shift condition. The calculation module is used to solve the optimization function under the constraint conditions using a multi-objective optimization algorithm to obtain the optimal solution set consisting of multiple sets of shift smoothness objective function values and shift time objective function values; A filtering module is used to filter a set of optimal optimization variables from the set of optimal solutions; The control module is used to output control commands to the power source and synchronizer according to a preset timing sequence based on the values of each optimization variable in the optimal set of optimization variables.
[0067] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0068] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0069] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A shift control method for a two-speed electronically controlled clutchless AMT, characterized in that, include: Determine the current shifting condition based on vehicle operating parameters; Construct an optimization function, which includes a shift smoothness objective function and a shift time objective function. The input parameters of the optimization function include a set of optimization variables corresponding to the shift condition. A multi-objective optimization algorithm is used to solve the optimization function under the constraints, and the optimal solution set is obtained, which consists of multiple sets of objective function values for shift smoothness and objective function values for shift time. Select a set of optimal optimization variables from the set of optimal solutions; Based on the values of each optimization variable in the optimal set of optimization variables, control commands are output to the power source and synchronizer according to a preset timing sequence.
2. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 1, characterized in that, The objective function for shift smoothness is calculated as follows: Calculate the ratios of the maximum impact, net torque fluctuation amplitude, and input shaft speed fluctuation amplitude to their respective preset reference thresholds; Multiply the three ratios by the preset impact weighting coefficient, torque fluctuation weighting coefficient, and input shaft speed fluctuation weighting coefficient respectively, and then add them together; The sum of the three weighting coefficients is 1.
3. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 2, characterized in that, The impact weighting coefficient is configured based on the vehicle's performance positioning. For comfort-oriented models, the configuration is greater than or equal to the first threshold. For sporty models, the configuration is less than or equal to the second threshold; The first threshold is greater than the second threshold.
4. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 1, characterized in that, The shifting conditions include upshifting and downshifting. The set of optimization variables corresponding to the shifting condition includes: Under upshifting conditions, the set of optimized variables includes the power source torque unloading rate, torque recovery rate, synchronizer shifting force, and synchronizer start-up timing. In downshifting mode, the set of optimized variables, in addition to the optimized variables included in upshifting mode, also includes the input shaft speed adjustment rate.
5. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 4, characterized in that, The constraints include at least the following: The speed difference when the synchronizers are engaged is less than or equal to a preset speed difference threshold. The torque interruption time is less than or equal to the preset torque interruption time threshold. The synchronizer shift force is less than or equal to the preset shift force threshold. The values of the power source torque unloading rate and torque recovery rate are within the preset torque adjustment rate range; In the downshifting operation, the input shaft speed adjustment rate is also within the preset speed adjustment rate range.
6. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 1, characterized in that, A multi-objective optimization algorithm is used to solve the optimization function under the constraints, including the following steps: Initialize the population, where each individual in the population is a combination of values from the set of optimization variables; Calculate the objective function value for each individual in the population; Perform non-dominated sorting of individuals in the population and calculate crowding distance; Based on the non-dominated sorting structure and crowding distance, the next generation population is generated through selection, crossover, and mutation operations. Repeat the above steps until the maximum number of iterations is reached, then output the optimal solution set.
7. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 1, characterized in that, Select a set of optimal optimization variables from the set of optimal solutions, including: For comfort-oriented vehicles, the solution to the objective function of minimizing ride comfort is chosen, while for sporty vehicles, the solution to the objective function of minimizing shift time is chosen.
8. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 1, characterized in that, The preset timing sequence is as follows: the synchronizer start action begins within a preset time after the power source torque is unloaded to the target torque.
9. The shift control method for a two-speed electronically controlled clutchless AMT as described in claim 4, characterized in that, Based on the values of each optimization variable in the optimal set of optimization variables, control commands are output to the power source and synchronizer according to a preset timing sequence, including: If the current operation is upshifting, the control commands include: the power source unloads torque at the torque unloading rate, delays the synchronizer start-up sequence, the electronically controlled synchronizer applies shifting force according to the synchronizer shifting force, and the power source restores torque at the torque recovery rate. If the current operation is downshifting, the control commands include: the power source unloads torque at the torque unloading rate, adjusts the speed at the speed adjustment rate, delays the synchronizer start-up sequence, the electronically controlled synchronizer applies shifting force according to the synchronizer shifting force, and the power source restores torque at the torque recovery rate.
10. A shift control system for a two-speed electronically controlled clutchless AMT, characterized in that, include: The judgment module is used to determine the current shifting condition based on vehicle operating parameters; A construction module is used to construct an optimization function, which includes a shift smoothness objective function and a shift time objective function. The input parameters of the optimization function include a set of optimization variables corresponding to the shift condition. The calculation module is used to solve the optimization function under the constraint conditions using a multi-objective optimization algorithm to obtain the optimal solution set consisting of multiple sets of shift smoothness objective function values and shift time objective function values; A filtering module is used to filter a set of optimal optimization variables from the set of optimal solutions; The control module is used to output control commands to the power source and synchronizer according to a preset timing sequence based on the values of each optimization variable in the optimal set of optimization variables.