A method of controlling a double clutch transmission fork

Abstract

This invention discloses a shift fork control method for a dual-clutch transmission with a shift fork mechanism but without a shift fork position sensor. First, a two-dimensional reference coordinate system is established, with the motion trajectory of the shift motor set as the x-axis and the motion trajectory of the shift motor set as the y-axis. Then, based on the hardware linkage position of the shift fork, the grooved motion trajectory of the long shift head of the shift mechanism is planned. Subsequently, based on the operating signals of the shift and shift motors, combined with the contact relationship between the shift head and the shift fork, the actual position of the shift fork without a position sensor is simulated and calculated. Finally, based on the coordinate system, the grooved trajectory, and the simulated position, the shift fork engagement action is achieved through the long shift head. This method has a simple framework, clear logic, and strong applicability. It achieves precise and reliable shift fork control without additional hardware costs, significantly improving the robustness and safety of dual-clutch transmission operation, and can be quickly implemented in automotive power transmission technology research and development projects.

Description

Technical Field

[0001] This invention relates to the field of automotive transmission control technology, specifically to a shift fork control method for a dual-clutch transmission shifting actuator. Background Technology

[0002] With the rapid development of dual-clutch transmission technology, the shift fork mechanism has gradually upgraded from the traditional hydraulic valve body shifting method to an electric motor-driven shifting control method. The electric motor-driven solution, with its advantages of fast response speed, high control precision, and simplified structure, has become the mainstream technology for dual-clutch transmissions in passenger vehicles.

[0003] Currently, most motor-driven gear shifting mechanisms on the market employ a symmetrical design for their shift forks. This allows for disengaging another gear controlled by the same clutch during pre-engagement, achieving gear interlocking and providing safety protection for the transmission. Meanwhile, to further simplify the hardware structure and reduce overall vehicle material costs and assembly complexity, the industry generally adopts a technical solution that eliminates the shift fork position sensor.

[0004] However, the elimination of the shift fork position sensor brings a core control challenge: the system cannot directly obtain the real-time actual position of the shift fork, but can only collect the operating signals of the gear selection and shifting motors themselves. How to accurately drive the gear selection and shifting mechanism through software algorithms under this hardware constraint, while simultaneously updating the shift fork position accurately in real time, becomes the core test of the robustness and safety of dual-clutch transmissions equipped with this type of gear selection and shifting actuator. Currently, there is no logically clear, universally applicable, and highly reliable control scheme that can achieve precise and controllable shift fork engagement and return to neutral without a shift fork position sensor. This makes it extremely prone to fatal malfunctions such as engagement failure, disengagement, jamming, and even simultaneous engagement of two gears, seriously affecting the operational safety and service life of the transmission. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a dual-clutch transmission shift fork control method. First, a two-dimensional reference coordinate system is established, with the motion trajectory of the gear selection motor set as the x-axis and the motion trajectory of the shift motor set as the y-axis. Then, based on the hardware linkage position of the shift fork, the grooved motion trajectory of the long shift head of the gear selection / shift mechanism is planned. Subsequently, based on the operating signals of the gear selection and shift motors, combined with the contact relationship between the shift head and the shift fork, the actual position of the shift fork without a position sensor is simulated and calculated. Finally, based on the coordinate system, the grooved trajectory, and the simulated position, the shift fork's gear engagement action is achieved through the long shift head. This method has a simple framework, clear logic, and strong applicability. It achieves precise and reliable shift fork control without additional hardware costs, significantly improving the robustness and safety of dual-clutch transmission operation, and can be quickly implemented in automotive power transmission technology research and development projects.

[0006] The objective of this invention is achieved through the following approach:

[0007] A method for controlling a shift fork in a dual-clutch transmission, applicable to a dual-clutch transmission with a shift fork mechanism but without a shift fork position sensor, includes the following steps:

[0008] 1) Establish a two-dimensional reference coordinate system with the motion trajectory of the gear selection motor in the gear shifting actuator as the x-axis and the motion trajectory of the shifting motor as the y-axis;

[0009] 2) Based on the position linked with the hardware shift fork, the long shift head movement trajectory of the gear selection mechanism is planned as a groove-shaped trajectory that corresponds one-to-one with the shift fork;

[0010] 3) Based on the operating signals of the gear selection motor and the gear shifting motor, and combined with the physical contact relationship between the shift head and the shift fork, the current actual position of each shift fork is calculated through software simulation;

[0011] 4) Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from simulation, the long shift head is controlled to move within the groove trajectory corresponding to the target shift fork to achieve the engagement of the target gear.

[0012] 5) Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from simulation, the target shift fork's return motion is completed by selecting either direct drive with a long shift head or linkage drive with a short shift head.

[0013] Preferably, in step 2), the software and hardware settings are matched with the following configuration:

[0014] 2-1) The first type is where shift forks A1 and A2 are both odd-numbered gears, and shift forks B1 and B2 are both even-numbered gears;

[0015] 2-2) The second type is where shift forks A1 and A2 are both even-numbered gears, and shift forks B1 and B2 are both odd-numbered gears;

[0016] 2-3) The third type is not limited to four shift forks A1, A2, B1, B2, and can also be adapted to three or more shift forks.

[0017] Preferably, in step 3), the operating signals of the gear selection motor and the gear shifting motor include the motor speed, position, voltage, current and temperature signals. The system only collects the above motor signals and does not collect the direct position signal of the shift fork.

[0018] Preferably, in step 3), the specific principle of calculating the current actual position of each shift fork through software simulation includes:

[0019] 3-1) When the long shifter head and the shift fork are not in contact, mark the maximum and minimum value ranges of the shift fork position according to the extreme position of the long shifter head.

[0020] 3-2) When the long shifter head contacts the shift fork and moves to the stall limit position, it is determined that the position of the shift fork is completely synchronized with the current position of the long shifter head;

[0021] 3-3) When the long lever head contacts the lever fork, but stops or reverses before reaching the limit position, the lever fork position is locked at the coordinate position at the moment the action stops.

[0022] 3-4) When the short shifter head contacts the shift fork, it is determined that the shift fork has entered the return-to-free process, and the return-to-free position of the shift fork is updated synchronously.

[0023] Preferably, in step 4), the execution sequence of the shift fork gear engagement action is as follows: first, the target shift fork slot trajectory selection in the x-axis direction of the two-dimensional reference coordinate system is completed by the gear selection motor, and then the gear engagement drive in the y-axis direction is completed by the shift motor to realize the engagement of the target gear.

[0024] Preferably, in step 5), the fork return action includes two optional execution methods:

[0025] 5-1) The first optional execution mode is the long shift head direct return mode: if the shift fork in the slot where the long shift head is currently located is engaged, the software controls the long shift head to move a preset distance in the opposite direction of the shift fork, thereby driving the shift fork to return to the empty position.

[0026] 5-2) The second optional execution mode is the short shifter linkage return mode: if the shift fork in the slot where the non-long shifter is currently located is engaged, the short shifter is driven to contact the target shift fork through the action of the shifting mechanism, and the target shift fork is driven to complete the return.

[0027] Preferably, in the short shifter linkage return mode in step 5-2), when the long shifter is in the groove trajectory of shift fork B1 and any gear of shift fork B2 is engaged, the shifting mechanism is controlled to move a preset distance in any shifting direction, so that shift fork B2 can be driven by the short shifter to complete the return.

[0028] Preferably, the two-dimensional reference coordinate system has reserved slots that do not affect different types of gears during the shifting process, in order to avoid the risk of mechanical interference from multiple shift fork actions.

[0029] Preferably, in step 3), the simulation calculation of the shift fork position is updated synchronously and in real time with the action execution of the gear selection and shifting motor.

[0030] Preferably, in step 4), the shifting action is completed only by driving the shift fork with the long shift head, and the short shift head does not participate in the shifting drive process.

[0031] The beneficial effects of this invention are as follows:

[0032] A method for controlling a shift fork in a dual-clutch transmission, applicable to a dual-clutch transmission with a shift fork mechanism but without a shift fork position sensor, includes the following steps:

[0033] 1) Establishment of a two-dimensional reference coordinate system: The motion trajectory of the gear selection motor in the gear shifting actuator is taken as the x-axis (horizontal coordinate), and the motion trajectory of the gear shifting motor is taken as the y-axis (vertical coordinate), thus establishing a two-dimensional reference coordinate system;

[0034] 2) Planning the grooved motion trajectory: Based on the position linked with the hardware shift fork, the motion trajectory of the long shift head of the gear shifting mechanism is planned as a grooved trajectory that corresponds one-to-one with the shift fork;

[0035] 3) Simulate the actual position of the shift fork: Based on the operating signals of the gear selection motor and the shift motor, and combined with the physical contact relationship between the shift head and the shift fork, the current actual position of each shift fork is calculated by software simulation.

[0036] 4) Execute the shift fork shifting action: Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from simulation, control the long shift head to move within the groove trajectory corresponding to the target shift fork to achieve the engagement of the target gear.

[0037] 5) Perform the return motion of the shift fork: Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from the simulation, the target shift fork is returned to its original position by selecting either direct drive via the long shift head or linkage drive via the short shift head.

[0038] This invention constructs a complete sensorless shift fork control system, completely replacing the hardware functions of the shift fork position sensor (e.g., achieving unified quantitative control of dual motor actions through the establishment of a two-dimensional coordinate system, clarifying the shift fork action boundary through slotted trajectory, achieving closed-loop control without sensors through position simulation, and covering all shifting requirements under all working conditions through dual-mode return-to-free mode, thus achieving precise and reliable control of the entire shift fork shifting and return-to-free process). It thoroughly solves the core industry problem of unobtainable shift fork position and uncontrollable action under sensorless solutions. No additional hardware is required throughout the process; all control actions can be completed solely based on the native signals of the dual motors. This significantly simplifies the transmission hardware structure, reduces material and assembly costs, and is highly versatile, allowing for rapid adaptation to different specifications of dual-clutch transmission hardware solutions.

[0039] Preferably, in step 2), the software and hardware settings are matched with the following configuration:

[0040] 2-1) The first type is where shift forks A1 and A2 are both odd-numbered gears, and shift forks B1 and B2 are both even-numbered gears;

[0041] 2-2) The second type is where shift forks A1 and A2 are both even-numbered gears, and shift forks B1 and B2 are both odd-numbered gears;

[0042] 2-3) The third type is not limited to four shift forks A1, A2, B1, B2, and can also be adapted to three or more shift forks.

[0043] This invention establishes a standardized gear configuration rule, which significantly reduces the debugging difficulty and adaptation cost of the control software, avoids the logical confusion and control risks caused by non-standard gear matching, improves the versatility of the solution and the efficiency of engineering implementation, and makes the entire solution fully compatible with the core hardware configuration of dual-clutch transmissions where "odd gears and even gears are controlled by two independent clutches". It ensures the interlock function of the same clutch gears from the gear matching level, and fundamentally avoids the fatal failure of simultaneous engagement of two gears.

[0044] Preferably, in step 3), the operating signals of the gear selection motor and the gear shifting motor include the motor speed, position, voltage, current and temperature signals. The system only collects the above motor signals and does not collect the direct position signal of the shift fork.

[0045] This invention eliminates the need for additional hardware for acquiring the shift fork position, enabling shift fork control solely based on the motor's native signal. It clearly defines the sole signal input source for the software algorithm, ensuring the closed-loop nature of the control logic. It possesses the core advantages of simple hardware structure, low material cost, and minimal hardware failure points.

[0046] Preferably, in step 3), the specific principle of calculating the current actual position of each shift fork through software simulation includes:

[0047] 3-1) When the long shifter head and the shift fork are not in contact, mark the maximum and minimum value ranges of the shift fork position according to the extreme position of the long shifter head.

[0048] 3-2) When the long shifter head contacts the shift fork and moves to the stall limit position, it is determined that the position of the shift fork is completely synchronized with the current position of the long shifter head;

[0049] 3-3) When the long lever head contacts the lever fork, but stops or reverses before reaching the limit position, the lever fork position is locked at the coordinate position at the moment the action stops.

[0050] 3-4) When the short shifter head contacts the shift fork, it is determined that the shift fork has entered the return-to-free process, and the return-to-free position of the shift fork is updated synchronously.

[0051] This invention performs shift fork position simulation without sensors, covering all operating conditions including contact / non-contact between the shift head and shift fork, action / stationary, and shifting / returning. These four simulation rules perfectly match the physical contact characteristics of the shift head and shift fork, requiring no complex algorithm model. The calculation logic is simple and the execution efficiency is high, allowing for rapid implementation in automotive-grade controllers. At the same time, it ensures the consistency and stability of shift fork position judgment, significantly improving the robustness of transmission control. Through simulation rules covering all scenarios, it achieves accurate calculation of the shift fork position under all operating conditions, providing precise positional basis for subsequent shifting and returning actions, and solving the technical challenge of "how to achieve accurate real-time identification of shift fork position without sensors".

[0052] Preferably, in step 4), the execution sequence of the shift fork gear engagement action is as follows: first, the target shift fork slot trajectory selection in the x-axis direction of the two-dimensional reference coordinate system is completed by the gear selection motor, and then the gear engagement drive in the y-axis direction is completed by the shift motor to realize the engagement of the target gear.

[0053] This invention's standardized action sequence reduces the difficulty of debugging the control software, avoids control deviations and mechanical shocks caused by the simultaneous operation of two motors, extends the mechanical service life of the gear shifting mechanism, improves the smoothness of the shifting process, standardizes the collaborative action logic of the two motors, and avoids faults such as shift fork jamming, gear grinding, gear engagement failure, and gear disengagement caused by executing the gear engagement action before the selection position is correct, thus greatly improving the success rate and reliability of the gear engagement action.

[0054] Preferably, in step 5), the fork return action includes two optional execution methods:

[0055] 5-1) The first optional execution mode is the long shift head direct return mode: if the shift fork in the slot where the long shift head is currently located is engaged, the software controls the long shift head to move a preset distance in the opposite direction of the shift fork, thereby driving the shift fork to return to the empty position.

[0056] 5-2) The second optional execution mode is the short shifter linkage return mode: if the shift fork in the slot where the non-long shifter is currently located is engaged, the short shifter is driven to contact the target shift fork through the action of the shifting mechanism, and the target shift fork is driven to complete the return.

[0057] This invention's dual-selection mode design eliminates the need for additional hardware costs, achieving reliable return-to-neutral operation under different working conditions solely through software logic. Simultaneously, it implements gear interlocking functionality for the dual-clutch transmission at the control level, avoiding the safety risks of simultaneous engagement of two gears on the same clutch, thus ensuring transmission operational safety. It comprehensively covers the return-to-neutral requirements of the dual-clutch transmission across all operating conditions. The long shifter direct return-to-neutral mode adapts to the shift fork return-to-neutral scenario after normal gear shifting, while the short shifter linked return-to-neutral mode adapts to the same clutch gear interlocking disengagement scenario under pre-engagement conditions, significantly improving operational adaptability.

[0058] Preferably, in the short shifter linkage return mode in step 5-2), when the long shifter is in the groove trajectory of shift fork B1 and any gear of shift fork B2 is engaged, the shifting mechanism is controlled to move a preset distance in any shifting direction, so that shift fork B2 can be driven by the short shifter to complete the return.

[0059] In other words, when the long shifter head of this invention is within the trajectory of shift fork B1, there is no need to switch positions; the short shifter head can complete the return of shift fork B2 to its neutral position through any directional movement. This execution logic perfectly adapts to the interlocking requirement of dual-clutch transmissions to "disengage another gear on the same clutch during pre-engagement," eliminating the need for additional motion path planning (i.e., the disengagement action can be completed without controlling the long shifter head to switch positions). The control logic is simple and efficient, achieving rapid return of adjacent shift forks on the same clutch. This not only significantly shortens the disengagement response time under pre-engagement conditions and improves the shifting speed and response efficiency of the dual-clutch transmission, but also avoids mechanical wear caused by frequent switching of positions by the long shifter head, extending the service life of the mechanism.

[0060] Preferably, the two-dimensional reference coordinate system has reserved slots that do not affect different types of gears during the shifting process, in order to avoid the risk of mechanical interference from multiple shift fork actions.

[0061] This invention's slotted design ensures that the long shifter head will not trigger non-target shift forks during position selection, further enhancing the gear interlock effect, preventing unexpected gear changes, and ensuring power safety during vehicle operation. Furthermore, this invention, from a trajectory planning perspective, completely avoids the mechanical interference risks associated with multiple shift forks and gears during shifting, preventing accidental triggering of non-target gears during shifting, and preventing malfunctions such as jamming and disengagement caused by shift fork malfunctions, significantly improving the stability and safety of the transmission operation.

[0062] Preferably, in step 3), the simulation calculation of the shift fork position is updated synchronously and in real time with the action execution of the gear selection and shifting motor.

[0063] This invention's synchronous real-time update mechanism ensures that the accurate position of the shift fork can be obtained at any time during motor operation, enabling timely response to abnormal conditions such as jamming and stalling. This improves the response speed of transmission fault protection, further enhances the robustness of the control system, avoids control deviations caused by shift fork position calculation lagging behind motor operation, ensures the real-time feedback of shift fork position, realizes closed-loop control of gear selection and shifting, and significantly improves the accuracy and response speed of gear shifting control.

[0064] Preferably, in step 4), the shifting action is completed only by driving the shift fork with the long shift head, and the short shift head does not participate in the shifting drive process.

[0065] The single-drive design of this invention simplifies the control logic of gear shifting, reduces software debugging difficulty, avoids action interference and control conflicts caused by multiple drive sources, and further improves the reliability and stability of gear shifting. This clearly defines the functional division of the long and short shift levers in the control logic, avoids malfunctions of the short shift lever during gear shifting, prevents the short shift lever from driving non-target shift forks during gear shifting, and completely avoids the risk of simultaneous engagement of two gears during gear shifting.

[0066] In summary, compared with the prior art, the present invention has the following significant technical advantages:

[0067] ① Core Function Breakthrough: Completely replaces the shift fork position sensor, achieving precise full-process control of the shift fork without sensors. This invention, through a simulation algorithm of the physical contact relationship between the shift head and the shift fork, relies solely on the native operating signals of the gear selection and shifting motors to accurately simulate and calculate the real-time actual position of the shift fork under all operating conditions. It completely replaces the position feedback function of the hardware shift fork position sensor, thoroughly solving the core industry problem of unobtainable shift fork position and uncontrollable movement in sensorless solutions.

[0068] ② Significantly Enhanced Safety and Robustness: A comprehensive safety guarantee is constructed from the control logic level. This invention clarifies the action boundaries of multiple shift forks through standardized groove trajectory planning, and, combined with the empty groove isolation design, completely avoids the mechanical interference risks of multiple shift fork and multiple gear actions; the dual-selectable return-to-empty mode is compatible with the interlocking requirements of the same clutch gear in a dual-clutch transmission, and can reliably complete disengagement and return-to-empty operation under pre-engaged conditions, fundamentally avoiding the fatal failure of simultaneous engagement of two gears; the full-condition shift fork position simulation covers all operating scenarios, effectively avoiding faults such as shift failure, disengagement, and jamming, significantly improving the robustness and safety of the transmission under all operating conditions.

[0069] ③ Significant Hardware and Cost Optimization: Simplifying the structure while reducing the total lifecycle cost. This invention eliminates the need for additional position sensors for each shift fork, and also eliminates the corresponding wiring harnesses, signal acquisition circuits, and hardware interfaces for the sensors. This significantly simplifies the hardware structure of the shifting actuator, directly reducing the material cost and assembly complexity of the transmission. At the same time, it reduces the number of failure points caused by vulnerable sensor components, lowering the after-sales failure rate, maintenance difficulty, and total lifecycle cost of the transmission.

[0070] ④ High versatility and adaptability: It can flexibly adapt to different transmission schemes. The slot trajectory planning of this invention does not limit the number of shift forks that can be adapted, and can flexibly adapt to dual-clutch transmission hardware schemes with different gear specifications; it reserves two standardized odd and even gear hardware and software configuration modes, which can match different transmission gear layout designs; two selectable return modes can adapt to different shifting conditions such as direct return after gearing and pre-engagement linkage disengagement, meeting the control needs of different driving scenarios of the whole vehicle.

[0071] ⑤ Outstanding Engineering Value: Significantly Reduces R&D Threshold and Improves Implementation Efficiency. This invention has a simple framework, clear logic, and strong applicability. It requires no complex algorithm models or additional hardware, and can be quickly ported and adapted to various dual-clutch transmission R&D projects equipped with motor-driven shift fork mechanisms. This significantly shortens the R&D cycle of automotive power transmission systems and reduces the debugging difficulty of control software and the cost of engineering implementation. Attached Figure Description

[0072] Figure 1 This is a schematic diagram of the gear shifting actuator and its direction of action provided in an embodiment of the present invention;

[0073] Figure 2 This is a schematic diagram of the long shift head action groove trajectory planning of the gear shifting actuator in an embodiment of the present invention;

[0074] Figure 3 This is a schematic diagram illustrating the execution of the shifting mechanism to achieve the shift fork action in an embodiment of the present invention. Detailed Implementation

[0075] like Figures 1 to 3 As shown, a dual-clutch transmission shift fork control method is applied to a dual-clutch transmission with a shift fork shifting mechanism but without a shift fork position sensor, and includes the following steps:

[0076] 1) Establish a two-dimensional reference coordinate system: such as Figure 1 As shown, for the gear selection motor and gear shifting motor of the gear shifting actuator, the trajectory of the gear selection motor is set as the x-axis of the coordinate system, and the trajectory of the gear shifting motor is set as the y-axis of the coordinate system. L corresponds to the long shift head, and S... 左 S 右 For short dial, E 左 E 右 The shifting process does not affect the empty slots of different types of gears;

[0077] 2) Planning the groove-shaped motion trajectory (i.e. determining the running trajectory of the gear shifting mechanism): Based on the position linked with the hardware shift fork, the long shift head motion trajectory of the gear shifting mechanism is planned as a groove-shaped trajectory that corresponds one-to-one with the shift fork.

[0078] In this invention, based on the positions linked to the hardware shift forks A1, A2, B1, and B2, the movement trajectory of the long shift head of the gear selection mechanism is planned as a groove-shaped trajectory. The groove-shaped trajectory of the long shift head's movement in this invention is as follows: Figure 2 As shown, shift fork A1 corresponds to the gear position ( , ), shift fork A2 corresponds to the gear ( , ), shift fork B1 corresponds to the gear ( , ), shift fork B2 corresponds to the gear ( , ).

[0079] There are actually three settings for the hardware and software settings:

[0080] One type has shift forks A1 and A2 with all odd-numbered gears, and shift forks B1 and B2 with all even-numbered gears;

[0081] Another configuration has shift forks A1 and A2 both having even-numbered gears, and shift forks B1 and B2 both having odd-numbered gears.

[0082] There is also a type that is not limited to four shift forks A1, A2, B1, B2, and can also be adapted to three or more shift forks;

[0083] Note that in this invention, reverse gear is assumed to be an even-numbered gear.

[0084] The motion diagram of the groove-shaped trajectory of the long-handled head is shown below. Figure 3 , Figure 3 The medium-length L-shaped shift head moves within the B1 groove of the shift fork, S 右 The short shifter operates within the B2 slot of the shift fork, E 左 The empty slot moves within the A1 slot of the shift fork, E 右 The empty slot moves within the A2 slot of the shift fork.

[0085] 3) Simulate the actual position of the shift fork: Based on the operating signals of the gear selection motor and the shift motor, and combined with the physical contact relationship between the shift head and the shift fork, the current actual position of each shift fork is calculated by software simulation.

[0086] In other words, the current system only has selector and shift motors, each with its own speed, position, voltage, current, and temperature. However, shift forks A1, A2, B1, and B2 do not have position sensors. Therefore, the software simulates and calculates the actual positions of shift forks A1, A2, B1, and B2 based on the motion trajectory of the selector and shift motors under the current structure. The simulation principle of this invention includes:

[0087] 3-1) When the long shifter head and the shift fork are not in contact, calculate the maximum and minimum values ​​of the shift fork based on the extreme positions of the long shifter head's movement;

[0088] 3-2) When the long shifter head contacts the shift fork and moves to the stall position, the position of the shift fork is the same as the position of the long shifter head;

[0089] 3-3) When the long shift head contacts the shift fork and does not reach its limit to stop or reverse, the shift fork is in the position it was in when it stopped.

[0090] 3-4) When the short shift head contacts the shift fork, the shift fork begins to return to neutral.

[0091] 4) Execute the shift fork shifting action: Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from simulation, control the long shift head to move within the groove trajectory corresponding to the target shift fork to achieve the engagement of the target gear.

[0092] In other words, such as Figure 3 As shown, under the established coordinates and the simulated actual position of the shift fork, the present invention uses the long dial of the shift mechanism to determine the position of the shift motor and the shift motor to engage the gear under the trajectory corresponding to shift forks A1, A2, B1, and B2, and finally engages the gear on the shift fork.

[0093] 5) Perform the return motion of the shift fork: Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from the simulation, the target shift fork is returned to its original position by selecting either direct drive via the long shift head or linkage drive via the short shift head.

[0094] Step 5: Shift fork return to neutral. The software, based on the established coordinates and the simulated actual position of the shift fork, offers two options for the shift fork return to neutral: First, utilize the long lever of the shift mechanism to achieve the shift fork return to neutral, such as... Figure 3 If the shift fork B1 is in position If it's already engaged, then the software controls the long lever to move towards the gear position. A directional movement of a certain distance returns the shift fork B1 to its neutral position; the first method utilizes the short shift lever of the gear selector mechanism to return the shift fork to its neutral position. For example... Figure 3 If shift fork B2 is in gear position , With any gear engaged, the long shift knob is in the B1 trajectory of the shift fork, and the shift mechanism moves to the gear. , The B2 lever can be returned to neutral by moving a certain distance in any direction.

[0095] The following is an example of the implementation of the above method. This example is a complete implementation of the present invention. All steps are completed under hardware constraints without a shift fork position sensor. Only the native operating signals of the gear selection and shifting motors are collected throughout the process, as detailed below:

[0096] 1. Application Scenarios and Hardware Foundation of the Implementation Examples

[0097] This embodiment applies to a front-engine, front-wheel-drive, transversely mounted 8-speed dual-clutch transmission. The core hardware configuration of this transmission is as follows:

[0098] 1.1 Transmission configuration: Odd-numbered gears (1st, 3rd, 5th, and 7th gears) are controlled by odd-numbered shaft clutches, and even-numbered gears (2nd, 4th, 6th, and R gears) are controlled by even-numbered shaft clutches, thus meeting the core requirement of odd-even gear separation control in a dual-clutch transmission;

[0099] 1.2 Gear shifting actuator:

[0100] 1.2.1 It is equipped with one permanent magnet synchronous gear selector motor and one permanent magnet synchronous shift motor, without any shift fork position sensor;

[0101] 1.2.2 The actuator is equipped with one long dial L and two symmetrically arranged short dials S. 左 S 右 The long and short dials move synchronously with the gear selection and shifting motors.

[0102] 1.3 Shift fork and gear configuration:

[0103] 1.3.1 There are a total of 4 shift forks. Shift forks A1 and A2 can be freely configured to gears 1, 3, 5, and 7, and shift forks B1 and B2 can be freely configured to gears 2, 4, 6, and R. For example, shift fork A1 corresponds to gears 1 and 3, shift fork A2 corresponds to gears 5 and 7, shift fork B1 corresponds to gears 2 and 4, and shift fork B2 corresponds to gears 6 and R.

[0104] 1.3.2 The hardware and software gear matching adopts a standardized configuration: shift forks A1 and A2 are all odd-numbered gears, and shift forks B1 and B2 are all even-numbered gears;

[0105] 1.4 Signal Acquisition: The transmission controller only acquires five types of signals: real-time speed, position, voltage, current, and temperature of the gear selection motor and shift motor. It does not acquire any direct position signals of the shift forks.

[0106] 2. Establishment and calibration of a two-dimensional reference coordinate system

[0107] The first step in this embodiment completes the construction and hardware calibration of the two-dimensional reference coordinate system, providing a unified quantitative benchmark for subsequent control. The specific implementation process is as follows:

[0108] 2.1 Coordinate axis definition: The linear motion trajectory of the gear selection motor is set as the x-axis of the two-dimensional reference coordinate system, and the linear motion trajectory of the gear shifting motor is set as the y-axis of the two-dimensional reference coordinate system;

[0109] 2.2 Origin and travel calibration:

[0110] 2.2.1 The rated stroke of the gear selector motor is determined to be 0~3000 steps and the rated stroke of the gear shifting motor is 0~4000 steps by using the motor stall calibration method;

[0111] 2.2.2 Set the x=0 and y=2000 steps as the origin of the two-dimensional coordinate system, corresponding to the initial neutral position of the gear shifting mechanism, such as... Figure 2 point o;

[0112] 2.3 Schematic diagram of gear shifting actuator operation

[0113] by Figure 3 For example, the target is in shift fork B1. A schematic diagram of the organization (such as...) Figure 1 ) acts on the trajectory diagram (e.g. Figure 2 If the long shift head L of the gear shifting actuator is in the slot of the shift fork B1 (target gear), then the gear shifting actuator is in the slot of the shift fork B1. (Shift), short shifter S 左 In the suspended position (simultaneously linked: no gear engaged), S 右 Positioned in slot B2 (simultaneously linked: causing B2 shift fork to return to neutral), E 左 The clearance is located in the slot of shift fork A1 (simultaneous linkage: unaffected), E 右 The clearance is in the slot of shift fork A1 (simultaneous linkage: unaffected), enabling the shifting actuator to perform shift fork shifting and shift fork return to neutral.

[0114] 3. Planning and calibration of the long-head grooved motion trajectory

[0115] Based on the hardware linkage positions of the four shift forks, this embodiment plans a slotted trajectory that corresponds one-to-one with the shift fork for the long shift head. Each slotted trajectory corresponds to a unique shift fork, covering the full stroke of the shift fork for both gear positions. The specific calibration is as follows:

[0116] 3.1 Corresponding slot trajectory for shift fork A1:

[0117] The x-axis range is 300-600 steps, and the y-axis full range covers 1000-3000 steps.

[0118] Where y=1000 steps correspond to the 1st gear engagement position, y=3000 steps correspond to the 3rd gear engagement position, and y=2000 steps correspond to the neutral position of shift fork A1.

[0119] 3.2 Corresponding slot trajectory for shift fork A2:

[0120] The x-axis range is 1000~1300 steps, and the y-axis full range covers 1000~3000 steps;

[0121] Where y=1000 steps correspond to the 5th gear engagement position, y=3000 steps correspond to the 7th gear engagement position, and y=2000 steps correspond to the neutral position of shift fork A2.

[0122] 3.3 Corresponding slot trajectory for shift fork B1:

[0123] The x-axis range is 1700~2000 steps, and the y-axis full range covers 1000~3000 steps;

[0124] Where y=1000 steps correspond to the 2nd gear engagement position, y=3000 steps correspond to the 4th gear engagement position, and y=2000 steps correspond to the neutral position of shift fork B1.

[0125] 3.4 Corresponding slot trajectory for shift fork B2:

[0126] The x-axis range is 2400~2700 steps, and the y-axis full range covers 1000~3000 steps;

[0127] Where y=1000 steps correspond to the 6th gear engagement position, y=3000 steps correspond to the R gear engagement position, and y=2000 steps correspond to the neutral position of shift fork B2.

[0128] 4. Implementation of simulation calculation for the actual position of the sensorless shift fork

[0129] This embodiment is based on the real-time operating signals of the gear selection and shifting motors, combined with the physical contact relationship between the shift head and the shift fork, and uses software algorithms to simulate and calculate the actual positions of the four sets of shift forks in real time. The specific implementation of the simulation rules is as follows:

[0130] 4.1 Determination of the action of the gear shifting actuator:

[0131] like Figure 3 When the long shifter is in shifting mode with the y-axis pointing downwards, and the position is at step 1000, engage shifter fork B1. During the process, the linkage fork B2 returns to neutral; when the long shift head moves and the shift y-axis direction is upward, at position 3000, shift fork B1 is engaged. During the process, all linkage forks B2 return to neutral; when the long shifter moves along the y-axis to ensure its position is around 2000 steps, shift forks B1 and B2 are in neutral. Throughout the entire process, the positions of shift forks A1 and A2 remain unchanged.

[0132] 4.2 Location determination in stalled synchronization scenarios:

[0133] When the long shifter head enters the x-axis slot area of ​​the target shifter fork, the shift motor drives the long shifter head to move to the y-axis limit position. When the motor current reaches the stall threshold of 8A and lasts for 20ms, it is determined that the long shifter head is in contact with the shifter fork and moves to the stall limit. At this time, the actual position of the shifter fork is completely synchronized with the current y-axis coordinate of the long shifter head.

[0134] Example: The gear selector motor moves to x=1700 steps (the slotted area of ​​shift fork B1), and the shift motor moves from y=2000 steps to y=3000 steps. The motor current reaches 8A and remains so for 20ms. At this point, the simulation determines that the actual position of shift fork B1 is y=3000 steps. The gear shift is complete;

[0135] 4.3 Position locking in mid-stop scenario: When the long shifter head contacts the shift fork, but the shift motor stops or reverses before reaching its limit position, the actual position of the shift fork is locked to the y-axis coordinate at the moment the motor stops moving.

[0136] Example: When the long shift head is in the slotted area of ​​shift fork A1, the shift motor stops moving when it moves from y=2000 steps to y=1500 steps. At this time, the simulation determines that the actual position of shift fork A1 is locked at y=1500 steps until the motor moves again.

[0137] 4.4 Short dial contact scenario position update: When the short dial S 左 / S 右 When the shift fork comes into contact with the corresponding shift fork and the shift motor is activated, it is determined that the shift fork has entered the return-to-neutral process. The return-to-neutral position of the shift fork is updated synchronously until the shift fork returns to the neutral position at y=2000 steps.

[0138] 4.5 Data Update: Update the gear selection position, number of gears, and the positions of the shift forks A1, A2, B1, and B2 mentioned above.

[0139] 5. Complete implementation example of shifting gears with the shift fork

[0140] In this embodiment, the gear is shifted into neutral (N) and then into shift fork position A1. Assuming the scenario is 1st gear, the complete shift fork engagement action is implemented. The entire process is based on a two-dimensional coordinate system and the real-time simulated shift fork position to complete closed-loop control. The specific steps are as follows:

[0141] 5.1 Initial state: The transmission is in N gear, the long shift lever of the shift mechanism is in neutral by default, the shift motor is at x=0 step origin, the shift motor is at y=2000 step origin, and all shift forks are in neutral. The simulation determines that all shift fork positions are at y=2000 steps.

[0142] 5.2 Gear Selection Motor Positioning: The controller controls the gear selection motor to move the long dial head along the x-axis to x=450 steps, enters the slotted trajectory range corresponding to the dial fork A1, and completes the precise positioning of the target dial fork;

[0143] 5.3 Gear Shifting Motor Drive: The controller controls the gear shifting motor to operate, driving the long shift head along the y-axis ( If it is in gear 1, the position moves until y=1000 steps. At this time, the current of the shift motor reaches the stall threshold of 8A and lasts for 20ms.

[0144] 5.4 Gear Engagement Completion Confirmation: Through position simulation algorithm, it is determined that the actual position of shift fork A1 is synchronized with the long shift head by y=1000 steps, confirming that the first gear engagement is completed. The controller latches the current shift fork position, completing the entire gear engagement process.

[0145] 6. Examples of two modes of implementation for the fork return motion

[0146] This embodiment implements two modes for different operating conditions: direct return to neutral with a long shift lever and linked return to neutral with a short shift lever, fully covering the return to neutral requirements of the dual-clutch transmission under all operating conditions. The specific implementation is as follows:

[0147] 6.1 Implementation of direct return mode for long dial

[0148] This mode is applicable to the return-to-empty scenario of the shift fork currently located in the slot of the long shift head, with ( Taking the return to neutral (in 4th gear) as an example, the specific steps are as follows:

[0149] 6.1.1 Initial state: The shift fork B1 is engaged in the 4th gear. The simulation determines that the position of the shift fork B1 is y=3000 steps, and the long shift head is in the groove range of the shift fork B1 at x=1150 steps.

[0150] 6.1.2 Neutral position operation: The controller controls the shift motor to drive the long dial head to move along the y-axis in the opposite gear direction (the direction of decreasing y) until the neutral position of y=2000 steps, at which point the motor current reaches the neutral stall threshold.

[0151] 6.1.3 Neutral gear return completion confirmation: Through position simulation algorithm, the actual position of shift fork B1 is determined to be updated synchronously to y=2000 steps, confirming that the 4th gear return to neutral gear is complete, and the controller latches the current neutral gear position.

[0152] 6.2 Implementation of Short-Short Turn-Off Linkage Return Mode

[0153] This mode is applicable to the return-to-free scenario of the shift fork in the slot where the non-long shift head is currently located, and is adapted to the gear interlock requirements of dual-clutch transmission pre-engagement conditions, in order to pre-engage ( If it is in 3rd gear, disengage ( For example, if it's a 5th gear, the specific implementation steps are as follows:

[0154] 6.2.1 Initial State:

[0155] The transmission is currently in ( If the driving condition is 2nd gear, the shift fork B1 is engaged in 2nd gear and the even-numbered clutches are engaged, and the long shift head L is in the shift fork A2 groove area of ​​x=1850 steps.

[0156] At the same time, the 5th gear of the odd-numbered gears is engaged, and the shift fork A2 position is y=1000 steps. The 5th gear must be returned to neutral (disengaged) before the 3rd gear is engaged.

[0157] 6.2.2 Execution of the linkage long-range return motion:

[0158] The controller controls the shift motor to move back to neutral along the neutral direction of the y-axis at a distance of y=2000 steps.

[0159] 6.2.3 Execution of the linked return-to-empty selection action:

[0160] The controller controls the gear selection motor to move, driving the long shift head of the gear selection mechanism to move along the x-axis towards the 3rd gear position of the shift fork A1 slot. It moves towards the neutral position (x=450 steps), at which point the short shift head S... 右 Enter the grooved section of shift fork A2, and the long shift head L is within the grooved section of shift fork A1;

[0161] 6.2.4 Execution of the linkage return to neutral gear shift action:

[0162] The controller controls the shift motor to move, driving the long shift head L of the shift mechanism to move along the y-axis in the 3rd gear direction (y=1000 steps) to engage the gear; at this time, the short shift head S is activated. 右 Return all gears on shift fork A2 to neutral.

[0163] 6.2.5 Return to empty state to complete the update:

[0164] After the shift motor moves to y = [500, 1000] steps, the actual position of shift fork A2 is updated to y = 2000 steps using the position simulation algorithm. The 5th gear return to neutral is completed, which meets the gear interlock requirements. The 3rd gear pre-engagement action can then be executed.

[0165] 7. Verification of the effects of the examples

[0166] This embodiment, through the complete process described above, achieves precise shifting and neutral control of all gears in an 8-speed dual-clutch transmission without any hardware constraints such as shift fork position sensors. Bench and vehicle verification has yielded the following results:

[0167] 7.1 The gear shifting success rate is 100%, with no gear shifting jamming, gear grinding, or gear slippage. The gear shifting response time is ≤300ms, meeting the requirements for vehicle power and smoothness.

[0168] 7.2 The simulation accuracy error of the shift fork position is ≤50 steps, and the deviation from the actual physical position of the shift fork is ≤0.2mm, which fully meets the control accuracy requirements of the transmission.

[0169] 7.3 Reliable interlocking of the same clutch gear is achieved throughout the entire process, with no failures of simultaneous engagement of two gears. The robustness and safety of the transmission operation meet automotive-grade requirements.

[0170] 7.4 The entire solution requires no additional hardware. Compared with the solution with shift fork position sensors, the material cost of a single transmission is reduced by more than 15%, the assembly complexity is reduced by 20%, and the after-sales failures caused by sensor wear parts are reduced, resulting in a significant reduction in the total life cycle cost.

[0171] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for controlling a shift fork in a dual-clutch transmission, characterized in that, Applied to dual-clutch transmissions with a shift fork mechanism but without a shift fork position sensor, and comprising the following steps: 1) Establish a two-dimensional reference coordinate system with the motion trajectory of the gear selection motor in the gear shifting actuator as the x-axis and the motion trajectory of the shifting motor as the y-axis; 2) Based on the position linked with the hardware shift fork, the long shift head movement trajectory of the gear selection mechanism is planned as a groove-shaped trajectory that corresponds one-to-one with the shift fork; 3) Based on the operating signals of the gear selection motor and the gear shifting motor, and combined with the physical contact relationship between the shift head and the shift fork, the current actual position of each shift fork is calculated through software simulation; 4) Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from simulation, the long shift head is controlled to move within the groove trajectory corresponding to the target shift fork to achieve the engagement of the target gear. 5) Based on the established two-dimensional reference coordinate system and the actual position of the shift fork obtained from simulation, the target shift fork's return motion is completed by selecting either direct drive with a long shift head or linkage drive with a short shift head.

2. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In step 2), the hardware and software settings are matched to the following configuration: 2-1) The first type is where shift forks A1 and A2 are both odd-numbered gears, and shift forks B1 and B2 are both even-numbered gears; 2-2) The second type is where shift forks A1 and A2 are both even-numbered gears, and shift forks B1 and B2 are both odd-numbered gears.

3. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In step 3), the operating signals of the gear selection motor and the gear shifting motor include the motor speed, position, voltage, current and temperature signals. The system only collects the above motor signals and does not collect the direct position signal of the shift fork.

4. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In step 3), the specific principle of calculating the current actual position of each shift fork through software simulation includes: 3-1) When the long shifter head and the shift fork are not in contact, mark the maximum and minimum value ranges of the shift fork position according to the extreme position of the long shifter head. 3-2) When the long shifter head contacts the shift fork and moves to the stall limit position, it is determined that the position of the shift fork is completely synchronized with the current position of the long shifter head; 3-3) When the long lever head contacts the lever fork, but stops or reverses before reaching the limit position, the lever fork position is locked at the coordinate position at the moment the action stops. 3-4) When the short shifter head contacts the shift fork, it is determined that the shift fork has entered the return-to-free process, and the return-to-free position of the shift fork is updated synchronously.

5. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In step 4), the execution sequence of the shift fork gear engagement action is as follows: first, the target shift fork slot trajectory selection in the x-axis direction of the two-dimensional reference coordinate system is completed by the gear selection motor, and then the gear engagement drive in the y-axis direction is completed by the shift motor to realize the engagement of the target gear.

6. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In step 5), the fork return motion includes two optional execution methods: 5-1) The first optional execution mode is the long shift head direct return mode: if the shift fork in the slot where the long shift head is currently located is engaged, the software controls the long shift head to move a preset distance in the opposite direction of the shift fork, thereby driving the shift fork to return to the empty position. 5-2) The second optional execution mode is the short shifter linkage return mode: if the shift fork in the slot where the non-long shifter is currently located is engaged, the short shifter is driven to contact the target shift fork through the action of the shifting mechanism, and the target shift fork is driven to complete the return.

7. The dual-clutch transmission shift fork control method according to claim 6, characterized in that, In the short shifter linkage return mode in step 5-2), when the long shifter is in the groove trajectory of shift fork B1 and any gear of shift fork B2 is engaged, the shifting mechanism is controlled to move a preset distance in any shifting direction, and the short shifter can drive shift fork B2 to complete the return.

8. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In the two-dimensional reference coordinate system, there are reserved slots that do not affect different types of gears during the shifting process, in order to avoid the risk of mechanical interference from multiple shift fork actions.

9. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In step 3), the simulation calculation of the shift fork position is updated synchronously and in real time with the action execution of the gear selection and shifting motor.

10. The dual-clutch transmission shift fork control method according to claim 1, characterized in that, In step 4), the shifting action is completed only by driving the shift fork with the long shifter head, and the short shifter head does not participate in the shifting process.

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