Calibration method and calibration system for double-clutch two-gear electric drive assembly

Abstract

The invention discloses a calibration method and system for a double-clutch two-gear electric drive assembly. The method comprises the following steps: calibrating a static rotating speed-pressure curve of a clutch, determining a rotating speed-pressure relation of a pump, and checking an oil path; performing motor calibration; torque-pressure mapping relation calibration is conducted on the first clutch and the second clutch, and pressure values when different torques reach the target sliding friction rotating speed under the multiple working conditions are recorded; and performing a power gear shifting test. The invention further discloses a corresponding calibration system, electronic equipment and a storage medium. The method comprehensively evaluates the performance of the assembly and verifies the torque transmission function through a systematic process, can assist in diagnosing hardware problems, provides a basis for control optimization, and fills the blank of calibration methods in the field.

Description

Technical Field

[0001] The present invention belongs to the field of electric drive assembly test methods, and in particular relates to a method and system for motor calibration, clutch calibration, and non-power interruption shift testing of a dual-clutch two-speed electric drive assembly. Background Art

[0002] With the development of new energy vehicle technology, the performance of the electric drive system, as a core component, directly affects the vehicle's power, economy, and driving experience. Currently, mainstream pure electric vehicles on the market mostly use single-speed reducers, which feature simple structures, relatively mature control strategies, and well-established calibration and testing methods.

[0003] However, to further enhance the performance of pure electric vehicles, particularly in terms of energy efficiency and top speed at high speeds, as well as acceleration at low speeds, dual-clutch, two-speed electric drive systems have begun to attract industry attention and are gradually being adopted in mass-produced vehicles. Compared to single-speed electric drives, two-speed electric drive systems utilize an additional shift mechanism to select the optimal transmission ratio for varying vehicle speeds and operating conditions, thereby optimizing the motor's operating range and improving overall efficiency. The dual-clutch mechanism is designed to minimize or eliminate power interruptions during gear shifts, enhancing driving comfort.

[0004] Despite the aforementioned advantages, dual-clutch, two-speed electric drive assemblies are more complex in structure and control. The precise control of the two clutches, the dynamic response of the motors, and the coordinated coordination between them are key to achieving their performance. Currently, the industry lacks systematic, standardized calibration and testing methods for these dual-clutch, two-speed electric drive assemblies. There is a lack of a set of guiding testing procedures that can comprehensively evaluate and verify motor performance, clutch torque transmission capacity, and shift quality. As a result, during product development and verification, engineers often rely on experience for debugging, which is inefficient and makes it difficult to ensure the accuracy and consistency of calibration results.

[0005] Therefore, the market urgently needs a motor calibration and clutch calibration method for dual-clutch two-speed electric drive assemblies to guide related testing work, ensure that the performance of the electric drive assembly meets the design requirements, and verify the clutch's torque transmission function and gear shifting smoothness. Summary of the Invention

[0006] The main purpose of the present invention is to provide a calibration method and calibration system for a dual-clutch two-speed electric drive assembly to solve the technical problem raised in the background technology that there is currently a lack of a systematic calibration test method for a dual-clutch two-speed electric drive assembly.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a calibration method for a dual-clutch two-speed electric drive assembly, the method comprising the following steps:

[0008] Calibrate the clutch static speed-pressure characteristic curve (PN curve) to determine the relationship between the speed of each pressure pump and the corresponding clutch pressure in the first clutch pressure pump and the second clutch pressure pump that cooperate with the dual clutch assembly, and check the patency of the oil circuit;

[0009] Perform motor calibration to determine the basic control parameters of the drive motor that works with the dual clutch assembly;

[0010] Calibrate the torque-pressure mapping relationship (TP Map) of the first clutch and the second clutch respectively to establish the torque-pressure correspondence relationship of the first clutch and the second clutch under different working conditions;

[0011] Perform powershift tests to verify torque interaction and speed regulation during upshifts and downshifts.

[0012] As a preferred technical solution, the clutch static speed-pressure characteristic curve calibration includes: adjusting the speed of the first clutch pressure pump and the second clutch pressure pump respectively under multiple preset oil temperature conditions (for example, 25±5°C, 40±5°C, 90±5°C), and measuring and recording the corresponding pressure values ​​of the first clutch and the second clutch at different pump speeds.

[0013] As a preferred technical solution, the clutch static speed-pressure characteristic curve calibration also includes: comparing the measured speeds of each clutch pressure pump with a preset reference value; if the measured clutch pressure pump speed is much smaller than the preset reference value when the clutch pressure reaches the design maximum value, it is judged that the oil circuit is blocked; if the measured clutch pressure pump speed is much larger than the preset reference value and the clutch pressure still does not reach the expected design pressure, it is judged that the pressure cannot be established, and the potential cause may be clutch leakage or oil channel leakage.

[0014] As a preferred technical solution, the motor calibration includes: calibrating the drive motor when the first clutch or the second clutch is in a fully tightened state; the motor calibration includes: at least one of: resolver zero position calibration, maximum torque to current ratio (MTPA) calibration, flux calibration, inductance calibration and maximum torque to voltage ratio (MTPV) calibration.

[0015] As a preferred technical solution, the torque-pressure mapping relationship calibration of the first clutch and the second clutch includes: for the first clutch and / or the second clutch, under multiple preset oil temperatures and multiple slip speed conditions, by adjusting the pressure applied to the clutch and the output torque of the drive motor, and recording the pressure value when the clutch reaches the target slip speed under different output torques.

[0016] As a preferred technical solution, the specific steps of calibrating the torque-pressure mapping relationship include:

[0017] a. Lock the first clutch or the second clutch and control its pressure to the maximum pressure;

[0018] b. at a first preset oil temperature, setting the wheel speed to a first preset sliding speed, and setting the initial input torque of the drive motor;

[0019] c. Gradually reduce the clutch pressure from the maximum pressure and observe the slipping speed. When the slipping speed increases to the first preset slipping speed and stabilizes, record the clutch pressure at that moment.

[0020] d. increasing the output torque of the drive motor by a preset torque step size until the maximum output torque of the motor is reached, repeating step c, and recording the pressure values ​​of the clutch at different torques;

[0021] e. Draw a pressure-torque curve based on the recorded torque and pressure values, and determine the pressure value corresponding to zero output torque by extrapolation as the half-engagement point pressure.

[0022] As a preferred technical solution, it also includes at least one of the following steps: controlling the sliding friction speed to multiple different second preset sliding friction speeds, and repeating steps c to e for the first clutch and / or the second clutch; adjusting the oil temperature to multiple different second preset oil temperatures, and repeating steps b to e for the first clutch and / or the second clutch.

[0023] As a preferred technical solution, the upshift test in the power shift test includes: under preset initial oil temperature and initial vehicle speed conditions, placing the dual-clutch two-speed electric drive assembly in a first-gear locked state; increasing the test bench speed to a speed corresponding to the shift point to trigger upshifting; performing torque interaction: the second clutch increases pressure and torque, and the first clutch decreases pressure and torque until the torque of the first clutch drops to the torque corresponding to its half-engagement point pressure; and performing drive motor speed regulation: reducing the drive motor speed to a speed corresponding to the second gear to complete the upshift.

[0024] As a preferred technical solution, the downshift test in the power shift test includes: reducing the test bench speed to a preset speed lower than the upshift shift point to trigger downshifting; regulating the drive motor speed: increasing the drive motor speed to a speed corresponding to the first gear; and performing torque interaction: the first clutch increases the pressure and torque, and the second clutch decreases the pressure and torque, until the torque of the second clutch decreases to the torque corresponding to its half-engagement point pressure, thereby completing the downshift.

[0025] In a second aspect, the present invention provides a calibration system for a dual-clutch two-speed electric drive assembly, comprising:

[0026] A clutch static characteristic calibration module, configured to execute the clutch static speed-pressure characteristic curve calibration step in the above method;

[0027] A motor calibration module, configured to execute the motor calibration steps in the above method;

[0028] A clutch torque-pressure mapping calibration module, configured to execute the torque-pressure mapping relationship calibration step in the above method;

[0029] The power shift test module is used to execute the power shift test step in the above method.

[0030] In a third aspect, the present invention provides an electronic device comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; the memory is used to store computer programs; and the processor is used to implement any of the methods described in the first aspect when executing the programs stored in the memory.

[0031] In a fourth aspect, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements any of the methods described in the first aspect.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. Systematicity and Completeness: This invention provides a complete calibration and testing process, from static characteristics to dynamic performance, and from the component level (motor, clutch) to the system level (gear shifting). It can comprehensively evaluate the key performance of the dual-clutch two-speed electric drive assembly, filling the gap in systematic calibration methods in this field.

[0034] 2. Strong guidance and practicality: The test conditions, operating steps, key parameters and judgment basis of each calibration item are specified in detail, providing engineers with clear test guidance and improving the efficiency and accuracy of calibration work.

[0035] 3. Fault Diagnosis: Preliminary diagnostic methods for common faults such as oil line blockage and leakage are incorporated into PN curve calibration, facilitating early detection and resolution of hardware issues. During power shift testing, monitoring the alignment of measured pressure with target pressure effectively determines whether clutch hydraulic system interactions or delayed response are occurring, enabling identification of potential hardware design flaws.

[0036] 4. Verify torque transmission function: Through the calibration of the torque-pressure map, the actual torque transmission capacity of the clutch under different working conditions can be accurately grasped, providing accurate data support for optimizing the clutch control strategy and ensuring the smoothness and reliability of the shifting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments disclosed in the present invention, the drawings of the embodiments will be briefly introduced below. These drawings are only used for illustrative purposes and are not intended to limit the scope of protection of the present invention.

[0038] Figure 1 The figure is a flow chart of a calibration method for a dual-clutch two-speed electric drive assembly provided in an embodiment of the present invention.

[0039] Figure 2 The estimated reference speed values ​​of the clutch pressure pumps (CAP1 pump and CAP2 pump) at different target pressures are shown at an oil temperature of 25°C ± 5°C.

[0040] Figure 3 2 is a schematic diagram of the present invention, showing a case of judging oil channel blockage in a PN curve test according to an embodiment of the present invention (the actual measured speed at the deadlock is much smaller than the design value).

[0041] Figure 4 2 is a schematic diagram of the present invention, showing a situation in which clutch or oil channel leakage is determined in a PN curve test according to an embodiment of the present invention (pressure cannot be built up, the speed is very high but the pressure cannot be increased).

[0042] Figure 5 2 is a schematic diagram of the present invention, showing a clutch torque-pressure relationship curve obtained by calibration according to an embodiment of the present invention and determination of a half-engagement point.

[0043] Figure 6 It is a schematic diagram of the present invention, showing the good followability of the measured pressures of the two clutches and the target pressure under ideal conditions during the power shift process.

[0044] Figure 7 It is a schematic diagram of the present invention, showing the problem that the measured pressures of the two clutches affect each other and do not follow the target pressure during the power shift process.

[0045] Figure 8 This is a schematic diagram of the present invention, showing the problem of sudden change in wheel torque caused by clutch pressure during power shifting.

[0046] Figure 9 It is a schematic diagram of the present invention, showing the problem of nonlinearity of the motor speed regulation curve during upshifting and the ideal linearity of the motor speed regulation curve during downshifting.

[0047] Figure 10 It is a schematic diagram of the present invention, showing the problem of torque following sudden change when torque switches interactively during gear shifting.

[0048] Figure 11 This is a schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following further describes the technical solutions (including preferred technical solutions) of the present invention through accompanying drawings and by enumerating some optional embodiments of the present invention. It should be understood that the embodiments described are merely some, and not all, of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0050] Example 1

[0051] like Figure 1 As shown, the present invention provides a calibration method for a dual-clutch two-speed electric drive assembly, which includes the following core steps:

[0052] 1. Calibrate the clutch static speed-pressure characteristic curve (PN curve): This step aims to determine the precise correspondence between the clutch pressure pump speed and the actual pressure established by the clutches (including the first clutch C1 and the second clutch C2). This is crucial for subsequent precise clutch pressure control. This calibration process also effectively verifies the clutch oil circuit's unobstructed flow and any abnormalities such as blockages and leaks. This calibration is typically performed under various preset oil temperature conditions (e.g., 25±5°C, 40±5°C, and 90±5°C). By gradually adjusting the clutch pressure pump speed, the pressure values ​​of each clutch at each pump speed are measured and recorded. Pressure adjustment can be performed in fixed increments (e.g., 0.5 bar).

[0053] 2. Motor calibration: After completing the basic clutch characteristic check, the drive motor requires comprehensive performance calibration. This step is typically performed with one clutch (for example, the first clutch C1, simulating the starting gear) fully engaged (i.e., transmitting maximum torque). Motor calibration is similar to conventional permanent magnet synchronous motor calibration, primarily including resolver zero position calibration, maximum torque-to-current (MTPA) calibration, magnetic flux calibration, inductance calibration, and maximum torque-to-voltage (MTPV) calibration. The accuracy of these calibrations directly impacts the precision and efficiency of motor control.

[0054] 3. Calibrate the torque-pressure mapping relationship of the two clutches to establish the torque-pressure correspondence of the first and second clutches at different sliding speeds and oil temperatures; including:

[0055] Calibrate the torque-pressure mapping (Torque-Pressure Map) for the first clutch, C1. This step aims to accurately determine the relationship between the torque capable of transmitting through the first clutch and the control pressure applied to it under various operating conditions (e.g., varying oil temperatures and slipping speeds). Calibration typically begins by locking the clutch to maximum pressure. Then, at a specific oil temperature and set wheel slipping speed (e.g., initially 50 rpm), starting with a low motor output torque (e.g., 10 Nm), the clutch pressure is gradually reduced until clutch slippage is observed and the target slipping speed is reached. The pressure at this point is recorded. The motor output torque is then gradually increased (e.g., in 10 Nm increments), and the pressure adjustment and recording process is repeated until the maximum motor output torque is reached. These data points are used to plot a torque-pressure curve, and the pressure at 0 Nm of torque, known as the "half-engagement point," is extrapolated to the pressure. This process is repeated at multiple different sliding speed points (such as a series of points from 300rpm to 6000rpm) and multiple different oil temperature points (such as 30℃, 60℃, 90℃, 120℃) to obtain comprehensive map data.

[0056] Calibrate the torque-pressure mapping relationship of the second clutch (C2): This step is similar to the calibration method of the first clutch. The purpose is to obtain the torque-pressure characteristics of the second clutch under various operating conditions.

[0057] 4. Powershift testing: After completing the static and quasi-static calibrations described above, dynamic shift testing is required to verify shift quality under simulated real-world driving conditions, including shift smoothness, speed, and torque continuity. Powershift testing primarily includes upshift and downshift testing.

[0058] In some embodiments of the present invention, during the clutch static speed-pressure characteristic curve calibration step, the measured clutch pressure pump speed is compared with a preset reference design value. If the measured pump speed is significantly lower than the design reference value when the clutch reaches the designed maximum pressure (locked state), this may indicate a blockage in the clutch oil circuit, necessitating an oil circuit inspection. Conversely, if the measured pump speed is significantly higher than the design reference value, but the clutch pressure still fails to reach the expected design pressure, this may indicate a clutch leak or an inability of the oil pump to effectively build pressure, necessitating inspection of the clutch seals and oil channels.

[0059] In some embodiments of the present invention, when calibrating the torque-pressure mapping relationship of the first clutch (or second clutch), the initial set conditions may be: an oil temperature of 30°C, a wheel speed (or equivalent test bench output end) set to 50 rpm (this low speed is mainly used to calibrate the slip characteristics and does not significantly affect the core of the slip-torque relationship), and an initial motor input torque of 10 Nm. The clutch pressure is then gradually lowered from the maximum pressure. When the slip speed is observed to begin a positive increase and stabilize at 50 rpm, the current clutch pressure is recorded. Thereafter, the motor output torque is increased in steps of 10 Nm until the motor reaches its maximum output torque Tmax. This operation is repeated, and the corresponding clutch pressure values ​​at different torques are recorded. After plotting the pressure-torque curve, the pressure value corresponding to a transmitted torque of 0 Nm is extrapolated using a linear equation (or other fitting method) to determine the pressure value corresponding to the half-engagement point pressure under this operating condition.

[0060] In some embodiments of the present invention, in order to obtain a more comprehensive torque-pressure map, the above calibration process is repeated at multiple different sliding speeds (e.g., 300 rpm, 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm) and multiple different oil temperatures (e.g., 60°C, 90°C, 120°C).

[0061] In some embodiments of the present invention, the upshift process in the power shift test is as follows:

[0062] Initial conditions: For example, the oil temperature is 30°C, the simulated vehicle speed is 0 km / h (the test bench speed is 0), and after the controller is powered on, the system automatically selects and locks in first gear.

[0063] Preparation stage: Increase the half-shaft speed of the test bench to a lower speed, such as 50 rpm, which is lower than the minimum speed corresponding to the shift point of the first gear.

[0064] Applying a load: The drive motor is given a target output torque, which is usually derived from the vehicle control strategy or preset test conditions.

[0065] Trigger upshift: gradually increase the speed of the test bench (simulating vehicle acceleration). When the speed reaches the preset shift point from first gear to second gear (the speed at this shift point is determined based on the conversion relationship between vehicle speed and half-axle speed, for example, by the formula V=N 半轴 *2πR * 60 / 1000, where V is the vehicle speed (km / h), N 半轴 is the half-shaft speed (rpm), R is the tire rolling radius (m), the transmission controller (TCU) triggers the upshift logic.

[0066] During the torque exchange phase, the TCU controls the second clutch (C2, the target upshift clutch) to begin increasing pressure and gradually transmitting torque. Simultaneously, it controls the first clutch (C1, the current clutch) to begin decreasing pressure and gradually reducing transmitted torque. This process requires smooth and coordinated torque changes in both clutches to prevent significant fluctuations in output torque. Torque exchange is essentially complete when the transmitted torque of the first clutch C1 drops to the torque corresponding to its half-engagement point pressure (or close to 0 Nm).

[0067] Speed ​​synchronization stage: After the torque interaction is completed or during the process, the TCU sends a speed control command to the motor controller (MCU) to control the speed of the drive motor to smoothly transition from the speed corresponding to the current first gear to the speed corresponding to the second gear.

[0068] Upshift completed: the drive motor speed and output torque are stable in the second gear state, the second clutch C2 is fully engaged or in a controlled slip state as required, and the system is locked in second gear.

[0069] In some embodiments of the present invention, the downshift process (e.g., from second gear to first gear) in the power shift test is as follows:

[0070] Trigger downshift: Gradually reduce the speed of the test bench (simulating vehicle deceleration). When the speed drops to the preset shift point from second gear to first gear (this shift point is usually lower than the corresponding upshift point by a set speed difference, such as 5-10km / h), the TCU triggers the downshift logic.

[0071] Speed ​​synchronization stage: The TCU sends a speed control command to the MCU to control the speed of the drive motor to smoothly transition from the speed corresponding to the current second gear to the speed corresponding to the first gear.

[0072] During the torque interaction phase, either simultaneously or after the motor speed is adjusted, the TCU controls the first clutch (C1, the downshift target clutch) to begin increasing pressure and gradually transmitting torque. Simultaneously, the TCU controls the second clutch (C2, the current clutch) to begin decreasing pressure and gradually reducing transmitted torque. Torque interaction is essentially complete when the transmitted torque of second clutch C2 drops to the torque corresponding to its half-engagement point pressure (or close to 0 Nm).

[0073] Downshift is completed: the drive motor speed and output torque are stable in first gear, the first clutch C1 is fully engaged or in a controlled slip state as required, and the system is locked in first gear.

[0074] Example 2

[0075] This invention provides a systematic calibration method for dual-clutch, two-speed electric drive assemblies, designed to comprehensively evaluate motor performance, clutch characteristics, and shift quality. This method primarily includes calibration of the clutch static PN (speed-pressure) curve, motor calibration, clutch 1 torque-pressure map calibration, clutch 2 torque-pressure map calibration, and power shift testing. These steps are performed in a logical sequence to ensure the accuracy and validity of the calibration data.

[0076] Before formal calibration begins, the prototype installation check is performed to ensure the dual-clutch, two-speed electric drive assembly is correctly and securely mounted on the test bench and that all sensors are properly connected. A low-voltage fault check is then performed on the controller to eliminate any electrical faults within the controller itself. Next, hardware and software parameter settings are performed, including preliminary configuration of test bench parameters and internal parameters of the controllers (TCU, MCU) to prepare for subsequent testing.

[0077] 1. Clutch static PN (speed-pressure) curve calibration:

[0078] The purpose of this step is to determine the relationship between the speed of the clutch pressure pumps (usually two, corresponding to the CAP1 and CAP2 pumps, controlling the first clutch C1 and the second clutch C2) and the actual clutch pressure buildup. This is the basis for achieving precise clutch pressure control. This test also provides a preliminary assessment of oil line blockage or leakage.

[0079] The test temperature points are set at 25±5℃, 40±5℃ and 90±5℃. Temperature control is achieved through a dedicated temperature control system to ensure that the oil temperature is stable within the specified range.

[0080] Pressure step: In steps of 0.5 bar, gradually increase from the lowest pressure (such as 0 bar or an initial pressure close to 0 bar) to the maximum working pressure designed for the clutch.

[0081] Testing process:

[0082] a. Under the selected oil temperature condition (for example, 25±5°C), first target the first clutch C1 (supplied by CAP1 pump).

[0083] b. Control the speed of the CAP1 pump to build up a pressure of 0.5 bar at C1 and record the actual speed of the CAP1 pump at this time.

[0084] c. Continue to increase the CAP1 pump speed until the C1 pressure reaches 1.0 bar and record the pump speed.

[0085] d. Continue this process, increasing the pressure of C1 step by step in 0.5 bar increments until the maximum design pressure is reached (e.g., 12 bar or 13 bar). Record the CAP1 pump speed corresponding to each pressure point.

[0086] e. Repeat steps ad above for the second clutch C2 (supplied by the CAP2 pump), and record the speed of the CAP2 pump at different pressures.

[0087] f. Change the oil temperature to 40±5℃ and 90±5℃, and repeat the above steps a.e.

[0088] Data analysis and fault diagnosis:

[0089] Compare the measured pump speed-pressure data with the design reference value, such as Figure 2 The reference data at 25℃±5℃ is shown for comparison. Figure 2 Recommended pump speeds for the CAP1 pump (driving C1) and the CAP2 pump (driving C2) at different target pressures are given. For example, when the C1 target pressure is 1 bar, the estimated pump speed for CAP1 is 534 rpm; when the C2 target pressure is 13 bar, the estimated pump speed for CAP2 is 1396 rpm.

[0090] Judgment of oil circuit blockage: Figure 3 , if the clutch pressure reaches the designed maximum value (locked state), the measured clutch pressure pump speed is much smaller than (for example, Figure 3 The measured speed at 12 bar is 700 rpm, while the design value may be 1200 rpm. This indicates that the required pump displacement (corresponding to the speed) is abnormally low when reaching the target pressure. This is probably because there is a blockage in the oil circuit, resulting in excessive resistance to the actual oil flow, or the pump itself is extremely efficient (unlikely). In this case, you should check whether the oil circuit is unobstructed, for example, whether the oil circuit is fully drilled as designed, or whether there are impurities blocking the oil circuit or the pressure limiting valve (such as Figure 3 (Note: "Pressure limiting valve is blocked by impurities" and "Oil passage is not drilled through" are marked in the figure.)

[0091] Leakage or failure to build pressure judgment: Figure 4 , if the measured clutch pressure pump speed is much greater than the design reference value, but the clutch pressure still cannot reach the expected design pressure (for example, Figure 4The figure shows that at a high speed of 4000 rpm, the pressure only reaches 3.3 bar, far below the design value. The design value of 3.3 bar may correspond to a pump speed of only 800 rpm. This indicates a leak in the clutch or oil circuit, or the pump's volumetric efficiency is too low, preventing effective pressure buildup. In this case, check the clutch seals (such as the piston seal ring for damage), the housing mating surface, and the space between the piston and the main hub for abnormal wear that could cause leakage, or any undiscovered leaks in the oil passages.

[0092] All data are recorded and the calibrated PN curve data is written into the control software as the basis for clutch pressure closed-loop control.

[0093] 2. Motor calibration:

[0094] After confirming that the clutch oil circuit and basic pressure building function are normal, calibrate the drive motor.

[0095] During motor calibration, fully engage clutch 1 and shift the vehicle into first gear. This position eliminates slip between the motor and wheels, facilitating accurate motor parameter identification. While this step only mentions first gear, second gear can also be used for motor calibration.

[0096] The motor calibration follows the general permanent magnet synchronous motor (PMSM) calibration method, which mainly includes:

[0097] Resolver zero calibration: This procedure determines the zero point of the motor's rotor position sensor. During calibration, the motor is first brought to a standstill. A specific current excitation method is then used to position the rotor to a known position, thereby determining the zero point of the resolver signal. This process needs to be repeated multiple times to ensure calibration accuracy.

[0098] MTPA (Maximum Torque Per Ampere) calibration: This process finds the current vector angle that produces maximum torque at a given current, optimizing motor efficiency and torque output. Under different speed and torque conditions, the ratio of the d-axis and q-axis currents is adjusted to find the current combination that produces maximum torque. This calibration process covers the full operating range of the motor and establishes a complete MTPA current table.

[0099] Flux Calibration: Determines the motor's flux characteristics for accurate motor control. By measuring the motor's flux under different current conditions, a flux vs. current curve is constructed.

[0100] Inductance calibration: This measures the motor's d / q-axis inductance, taking into account its nonlinear characteristics as it changes with current. Inductance calibration measures the motor's inductance parameters under different operating conditions. Because the motor's inductance varies with current, measurements are performed at multiple operating points to create an inductance parameter table.

[0101] MTPV (Maximum Torque Per Voltage) calibration: This technique seeks a control strategy that maximizes electromagnetic torque under voltage constraints (typically in the high-speed field-weakening region) and determines the motor's maximum voltage output capability at various speeds. MTPV calibration primarily targets high-speed operating conditions, optimizing the current control strategy to achieve maximum torque under voltage constraints.

[0102] These calibration steps are typically completed on-site by professional electronic control engineers using the motor control unit (MCU)'s debugging interface and dedicated calibration software. The calibration results (such as motor parameter tables and control maps) are stored in the MCU for real-time motor control.

[0103] 3. Clutch torque-pressure map calibration:

[0104] Perform torque-pressure map calibration for the first clutch C1 and the second clutch C2 respectively. Take the first clutch C1 as an example:

[0105] Initial conditions:

[0106] The first clutch C1 is loaded to the maximum pressure through oil pressure control to ensure that it is in a locked state.

[0107] Adjust the oil temperature to the target value, for example 30°C.

[0108] Set the wheel speed (or the driven end speed of the test bench) to a low slip speed, such as 50 rpm. This speed setting is to observe clear slip when the clutch begins to transmit torque but is not completely locked.

[0109] The drive motor outputs an initial torque, for example 10 Nm.

[0110] Calibration process:

[0111] a. Find the engagement pressure at a specific torque: Under the aforementioned initial conditions, gradually reduce the pressure applied to C1 from maximum pressure. At the same time, closely observe C1's slip speed (the difference between the driving and driven speeds, or directly measure the slip at the beginning of wheel rotation). When the slip speed begins to increase from 0 (or close to 0) and stabilizes at the preset 50 rpm, record the actual C1 pressure at that moment. This pressure is the minimum engagement pressure required for C1 to transmit 10 Nm of torque at the current oil temperature and a slip speed of 50 rpm.

[0112] b. Increase torque and repeat: Maintaining the oil temperature and target friction speed (50 rpm), increase the drive motor's output torque by one step, for example, to 20 Nm. Starting again from a higher pressure (ensuring that C1 can transmit 20 Nm without excessive friction), reduce the pressure on C1 until the friction speed stabilizes at 50 rpm. Record the pressure at this point.

[0113] c. Repeat step b, increasing the motor output torque in 10 Nm increments until the motor reaches its maximum output torque, Tmax (or the maximum torque the clutch is designed to withstand). Record the C1 pressure value corresponding to each torque point.

[0114] d. Draw the torque-pressure curve and extrapolate the half-engagement point: Based on a series of recorded (torque, pressure) data points, draw the torque-pressure curve at the oil temperature and 50 rpm sliding speed. Figure 5 This curve is typically approximately linear. By performing a linear fit (or other suitable curve fit) on these data points, we can derive the functional relationship between torque T and pressure P: T = kP + b. Then, setting T = 0, we solve for the corresponding pressure value, P_half_engagement = -b / k. This pressure value is the theoretical "half-engagement" pressure, representing the critical pressure at which the clutch initially engages but has not yet transmitted macroscopic torque.

[0115] e. Calibration at Different Sliding Speeds: Maintaining the oil temperature constant (e.g., 30°C), set the target sliding speed to a series of different values, such as 300 rpm, 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, and 6000 rpm. Repeat steps a through d above at each sliding speed to obtain torque-pressure characteristic data and the half-engagement pressure at each sliding speed.

[0116] f. Calibration at different oil temperatures: Adjust the oil temperature to different target values, such as 60°C, 90°C, and 120°C. Repeat step e at each oil temperature (i.e., calibrate for all preset sliding speed points).

[0117] g. Repeat all the above calibration processes for the second clutch C2.

[0118] Data application: All calibrated torque-pressure map data (usually stored in the form of a multi-dimensional lookup table) will be written into the TCU, serving as the core basis for the TCU to accurately control the clutch engagement pressure and transmitted torque.

[0119] 4. Power shift test:

[0120] After completing the static and quasi-static calibration of the motor and clutch, a power shift test is carried out to verify the coordinated matching performance and shift quality of the entire system under dynamic conditions.

[0121] Preparation:

[0122] Set the initial oil temperature, for example 30°C.

[0123] Ensure that the vehicle (or the test bench simulated vehicle) is stationary (vehicle speed 0 km / h, test bench speed 0).

[0124] When the controller (TCU / MCU) is powered on, the system should automatically select first gear and lock it.

[0125] Increase the half-shaft speed of the test bench (representing the wheel speed) to a lower initial speed, such as 50rpm. This speed should be lower than the half-shaft speed corresponding to the lowest shift speed from first gear to second gear.

[0126] The drive motor is given a target output torque, which is usually set according to the test requirements (for example, to simulate medium load acceleration).

[0127] Upshift test (from first gear to second gear):

[0128] a. Trigger upshift: gradually and steadily increase the test bench speed to simulate the vehicle acceleration process. The TCU will monitor the vehicle speed in real time (calculated by parameters such as half-axle speed and tire radius, vehicle speed V = N 半轴 *2πR * 60 / 1000, where V is the vehicle speed (km / h), N 半轴 is the half-shaft speed (rpm), and R is the tire rolling radius (m). When the vehicle speed reaches the preset shift point from first gear to second gear (for example, a certain vehicle speed V_upshift), the TCU issues an upshift command.

[0129] b. Torque interaction:

[0130] The TCU controls the second clutch C2 (target gear clutch) to start increasing pressure, causing it to gradually transmit torque.

[0131] At the same time, the TCU controls the first clutch C1 (current gear clutch) to start reducing the pressure, so that the torque it transmits gradually decreases.

[0132] Ideally, the reduction in C1 torque should be matched in real time with the increase in C2 torque, so that the total torque output to the wheels remains stable or changes along the desired trajectory to avoid gear shift shock.

[0133] When the transmitted torque of C1 is reduced to the torque corresponding to its semi-engagement point pressure (or the preset minimum value, close to 0 Nm), C1 is basically separated and the torque interaction stage is completed.

[0134] c. Speed ​​synchronization: During or after the torque interaction, the TCU sends a speed control command to the MCU. The MCU controls the speed of the drive motor to smoothly reduce the speed from the current operating speed corresponding to the first gear to the operating speed corresponding to the second gear.

[0135] d. Upshift complete: C2 is fully engaged (or the target slip state is reached), the motor speed matches the load, and the system stabilizes in second gear. Key parameters throughout the upshift process are recorded, including clutch pressure, motor torque / speed, axle torque / speed, and slip power.

[0136] Downshift test (downshift from second gear to first gear):

[0137] a. Triggering a downshift: While the vehicle (or test bench) is traveling in second gear, gradually and steadily reduce the test bench's speed to simulate vehicle deceleration. When the vehicle speed drops to the preset shift point (e.g., vehicle speed V_downshift, typically V_downshift < V_upshift, with a hysteresis interval between the two, such as a 5-10 km / h speed difference), the TCU issues a downshift command.

[0138] b. Speed ​​synchronization: The TCU sends a speed control command to the MCU, which controls the drive motor to smoothly increase its speed from the current operating speed corresponding to second gear to the operating speed corresponding to first gear (because the first gear transmission ratio is larger, the motor speed is higher at the same vehicle speed).

[0139] c. Torque interaction:

[0140] The TCU controls the first clutch C1 (target gear clutch) to start increasing pressure, causing it to gradually transmit torque.

[0141] At the same time, the TCU controls the second clutch C2 (current gear clutch) to start reducing the pressure, so that the torque it transmits gradually decreases.

[0142] When the transmitted torque of C2 is reduced to the torque corresponding to its semi-engagement point pressure (or the preset minimum value), C2 is basically separated and the torque interaction stage is completed.

[0143] d. Downshift complete: C1 is fully engaged (or the target slip state is reached), the motor speed matches the load, and the system stabilizes in first gear. Record the key parameters throughout the downshift process.

[0144] Monitoring and problem diagnosis during power shifting:

[0145] During power shift testing, the following parameters need to be closely monitored to determine shift quality and potential problems:

[0146] Clutch pressure followability: Figure 6Ideally, the measured pressure of the two clutches should be able to quickly and accurately follow the target pressure command given by the TCU. Figure 7 If the measured pressure shown deviates significantly from the target pressure, or if the pressures of the two clutches interfere severely with each other (for example, the pressure buildup of one clutch affects the pressure maintenance of the other clutch), this indicates a problem with the clutch hydraulic control system or control strategy, requiring investigation of the hardware design (such as the oil circuit, accumulator) or optimization of the software control logic.

[0147] Wheel torque changes: Figure 8 During the torque interaction phase of a gear shift, the measured torque at the wheel (axle) should transition smoothly. If there's a sudden drop in torque (a sense of power interruption) or an excessive spike (a sense of impact), it indicates inaccurate or poorly coordinated clutch torque control. This may be related to the precision of pressure control, the accuracy of the torque-pressure mapping, and the torque interaction strategy.

[0148] Motor speed regulation curve: Figure 9 During the speed synchronization phase of gear shifting, the motor speed should change smoothly and linearly (or follow the desired curve). Figure 9 As shown in the figure, if the motor speed control curve shows obvious nonlinearity, steps or oscillations during the upshift process, it indicates that there is a problem with the MCU's motor speed control response or the coordination between the TCU and MCU. It is necessary to optimize the motor control algorithm or the communication and coordination strategy between the two. Figure 9 At the same time, it shows an ideal linear downshift speed curve.

[0149] Torque following and switching: Figure 10 After the torque interaction is completed and the clutch is switched from one dominant clutch to another, or when the speed control is switched back to the torque control, the actual output torque of the motor (or the clutch transmission torque) should be able to smoothly follow the target torque. Figure 10 The torque mutation shown in requires optimization of the torque estimation and control strategy during the shift process.

[0150] Example 3

[0151] The present invention also provides a calibration system for a dual-clutch two-speed electric drive assembly, which is used to perform the calibration method described in the above-mentioned embodiment 1 or 2. The calibration system at least includes:

[0152] Clutch static characteristic calibration module, used to perform clutch PN curve calibration;

[0153] Motor calibration module, used to calibrate various performance parameters of the drive motor;

[0154] Clutch torque-pressure mapping calibration module, used to calibrate the clutch TP Map;

[0155] Powershift test module for performing dynamic tests of upshifts and downshifts.

[0156] In some embodiments of the present invention, the clutch torque-pressure mapping calibration module includes:

[0157] A first clutch torque-pressure mapping calibration module, used to calibrate the TP Map of the first clutch;

[0158] The second clutch torque-pressure map calibration module is used to calibrate the TP Map of the second clutch.

[0159] Example 4

[0160] like Figure 11 As shown, the present invention provides an electronic device, including a processor 1, a communication interface 2, a memory 3 and a communication bus 4, wherein the processor 1, the communication interface 2, and the memory 3 communicate with each other through the communication bus 4; the memory 4 is used to store computer programs; the processor 1 is used to implement the calibration method of the dual-clutch two-speed electric drive assembly described in Example 1 or 2 when executing the program stored in the memory 3.

[0161] The processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0162] The memory may include a random access memory (RAM) or a non-volatile memory (NVM), such as at least one disk memory.

[0163] The memory may be a volatile memory, such as random-access memory (RAM); a non-volatile memory, such as read-only memory, flash memory, a hard disk drive (HDD), or a solid-state drive (SSD); or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may be a combination of the above.

[0164] Example 5

[0165] The present invention provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, it is a calibration method for a dual-clutch two-speed electric drive assembly as described in Example 1 or 2.

[0166] The present invention can be implemented in whole or in part through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions. When loaded and executed on a computer, the computer program instructions fully or partially perform the processes or functions described in accordance with the embodiments of the present invention. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0167] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A calibration method for a dual-clutch two-speed electric drive assembly, characterized in that: The following steps are involved: Perform clutch static speed-pressure characteristic curve calibration to determine the relationship between the speed of each clutch pressure pump and the clutch pressure, and check the oil circuit patency; Perform motor calibration to determine the basic motor control parameters of the electric drive system; Calibrate the torque-pressure mapping relationship of the first clutch and the second clutch respectively to establish the torque-pressure corresponding relationship of the first clutch and the second clutch under different working conditions; Perform powershift tests to verify torque interaction and speed regulation during upshifts and downshifts.

2. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 1, characterized in that: The clutch static speed-pressure characteristic curve calibration includes: Under multiple preset oil temperature conditions, the rotational speeds of the first clutch pressure pump and the second clutch pressure pump are adjusted respectively, and the corresponding pressure values ​​of the first clutch and the second clutch at different pump rotational speeds are measured and recorded.

3. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 2, characterized in that: The clutch static speed-pressure characteristic curve calibration further includes: comparing the measured speed of each clutch pressure pump with a preset reference value; If the clutch pressure reaches the designed maximum value and the measured clutch pressure pump speed is much smaller than the preset reference value, it is determined that the oil circuit is blocked; If the measured clutch pressure pump speed is much greater than the preset reference value and the clutch pressure still does not reach the expected design pressure, it is determined that the pressure cannot be built up, and the potential cause is clutch leakage or oil channel leakage.

4. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 1, characterized in that: The motor calibration includes: When the first clutch or the second clutch is in a fully tightened state, calibrating the drive motor; The motor calibration includes at least one of resolver zero position calibration, maximum torque current ratio calibration, flux calibration, inductance calibration and maximum torque voltage ratio calibration.

5. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 1, characterized in that: The calibrating the torque-pressure mapping relationship of the first clutch and the second clutch includes: For the first clutch and / or the second clutch, under multiple preset oil temperatures and multiple slip speed conditions, by adjusting the pressure applied to the clutch and the output torque of the drive motor, the pressure value when the clutch reaches the target slip speed under different output torques is recorded.

6. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 5, characterized in that: The specific steps of calibrating the torque-pressure mapping relationship include: a. Lock the first clutch or the second clutch and control its pressure to the maximum pressure; b. at a first preset oil temperature, setting the wheel speed to a first preset sliding speed, and setting the initial input torque of the drive motor; c. Gradually reduce the clutch pressure from the maximum pressure and observe the slipping speed. When the slipping speed increases to the first preset slipping speed and stabilizes, record the clutch pressure at that moment. d. increasing the output torque of the drive motor by a preset torque step size until the maximum output torque of the motor is reached, repeating step c, and recording the pressure values ​​of the clutch at different torques; e. Draw a pressure-torque curve based on the recorded torque and pressure values, and determine the pressure value corresponding to zero output torque by extrapolation as the half-engagement point pressure.

7. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 6, characterized in that: Also includes at least one of the following steps: Controlling the sliding friction speed to a plurality of different second preset sliding friction speeds respectively, and repeating steps c to e for the first clutch and / or the second clutch; The oil temperature is adjusted to a plurality of different second preset oil temperatures respectively, and steps b to e are repeated for the first clutch and / or the second clutch.

8. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 1, characterized in that: The upshift test in the power shift test includes: Under the conditions of a preset initial oil temperature and an initial vehicle speed, the dual-clutch two-speed electric drive assembly is placed in a first-gear locked state; Increase the test bench speed to the speed corresponding to the shift point to trigger an upshift; Perform torque interaction: the second clutch increases pressure and torque, and the first clutch decreases pressure and torque, until the torque of the first clutch decreases to the torque corresponding to the pressure of its half-engagement point; Perform drive motor speed regulation: reduce the drive motor speed to the speed corresponding to the second gear to complete the upshift.

9. The calibration method of a dual-clutch two-speed electric drive assembly according to claim 1, characterized in that: The downshift test in the power shift test includes: reducing the bench speed to a preset speed below the upshift shift point to trigger a downshift; Carry out speed regulation of the driving motor: increase the speed of the driving motor to the speed corresponding to the first gear; Torque interaction is performed: the first clutch increases pressure and torque, and the second clutch decreases pressure and torque until the torque of the second clutch drops to the torque corresponding to its half-engagement point pressure, completing the downshift.

10. A calibration system for a dual-clutch two-speed electric drive assembly, comprising: A clutch static characteristic calibration module, configured to execute the clutch static speed-pressure characteristic curve calibration step as described in claim 2 or 3; A motor calibration module, configured to execute the motor calibration step according to claim 4; A clutch torque-pressure mapping calibration module, configured to perform the torque-pressure mapping relationship calibration step according to any one of claims 5 to 7; A power shift test module, used to execute the power shift test step described in claim 8 or 9.

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