Zero drift correction method for DCT transmission pressure sensor

Abstract

The invention aims to provide a null drift correction method for a pressure sensor of a DCT (Discrete Cosine Transformation) transmission, which aims to overcome the corresponding defects in the prior art, and comprises the following steps of: setting a plurality of variable quantity thresholds and a plurality of pressure calculation formulas, and comparing the variable quantity of a voltage value of the pressure sensor of the DCT transmission with the variable quantity thresholds, so as to correct the null drift of the pressure sensor of the DCT transmission. According to the comparison result, the pressure of the clutch is calculated through a pressure calculation formula, the output result of the pressure sensor can be corrected, no additional correction element needs to be additionally arranged, in other words, the cost of the whole vehicle is not increased, the pressure error (within the altitude range of 0-5000 m) generated due to the influence of the altitude can be reduced to the maximum extent, and the reliability of the whole vehicle is improved. And the maximum value of the pressure error is not greater than or equal to 0.5 bar, so that the problem that the output precision of the pressure sensor is reduced due to null drift abnormity of the pressure sensor in the DCT transmission in negative pressure environments such as high altitude and the like is effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of DCT transmission systems, and in particular to a zero drift correction method for a DCT transmission pressure sensor. Background Art

[0002] The DCT transmission utilizes two clutches, each equipped with a pressure sensor. Each pressure sensor monitors the clutch hydraulic system pressure in real time, converting the clutch hydraulic pressure signal into an electrical signal that is transmitted to the DCT transmission control unit (TCU). The TCU, upon receiving the pressure sensor signal, regulates clutch hydraulic pressure by controlling components such as the electromagnetic threshold in the clutch hydraulic system, thereby achieving precise control over the degree of clutch engagement and disengagement.

[0003] However, the DCT transmission's pressure sensor, a sensing element that converts pressure signals into measurable electrical or other signals, is extremely sensitive to changes in ambient air pressure. When ambient air pressure drops significantly (for example, when a vehicle travels from a low altitude to a high altitude), the pressure balance within the pressure sensor is disrupted, causing zero drift. This reduces the accuracy of the pressure sensor's output signal, affecting the TCU's clutch control accuracy, potentially causing vehicle shock or even drivability. Summary of the Invention

[0004] The purpose of the present invention is to address the corresponding deficiencies of the existing technology and provide a zero drift correction method for a DCT transmission pressure sensor. By setting multiple change thresholds and multiple pressure calculation formulas, and comparing the voltage value change of the DCT transmission pressure sensor with the change thresholds, the pressure calculation formula is used to calculate the clutch pressure based on the comparison result, so as to correct the output result of the pressure sensor.

[0005] The purpose of the present invention is to adopt the following scheme to achieve: A zero drift correction method for a DCT transmission pressure sensor comprises the following steps: 1) Setting a first change threshold and a second change threshold to serve as a basis for correcting the first pressure sensor and the second pressure sensor; 2) reading a basic static voltage value of a first pressure sensor of the DCT transmission and using it as a first basic static voltage value, and reading a basic static voltage value of a second pressure sensor of the DCT transmission and using it as a second basic static voltage value; 3) collecting a voltage value of the first pressure sensor in a static state and using it as a first static voltage value, and collecting a voltage value of the second pressure sensor in a static state and using it as a second static voltage value; 4) Calculating the difference between the first basic static voltage value and the first static voltage value to obtain a change in the first static voltage value; 5) Calculating the difference between the second basic static voltage value and the second static voltage value to obtain a change in the second static voltage value; 6) Correcting the first pressure sensor and the second pressure sensor according to the first change threshold, the second change threshold, the first static voltage value change, and the second static voltage value change.

[0006] Preferably, in step 6), the specific manner of correcting the first pressure sensor and the second pressure sensor according to the first change threshold, the second change threshold, the first static voltage value change, and the second static voltage value change includes: 6-1) Calculate the absolute value of the first static voltage value change and the absolute value of the second static voltage value change respectively, and combine them with the first change threshold to correct the first pressure sensor and the second pressure sensor in the following manner: ① If |the change in the first static voltage value| is less than or equal to the first change threshold, and |the change in the second static voltage value| is less than or equal to the first change threshold, the first and second pressure sensors are corrected using the default pressure calculation formula; ② If |the change in the first static voltage value| is greater than the first change threshold, or |the change in the second static voltage value| is greater than the first change threshold, the first pressure sensor and the second pressure sensor are corrected using the first pressure calculation formula; ③ If |the change in the first static voltage value| is greater than the first change threshold, and |the change in the second static voltage value| is greater than the first change threshold, then the first pressure sensor and the second pressure sensor are corrected in combination with the second change threshold; 5-2) Based on the second change threshold, the first and second pressure sensors are corrected in the following manner: ① If || first static voltage value change|-| second static voltage value change|| < second change threshold, the first pressure sensor and the second pressure sensor are corrected using the second pressure calculation formula; ② If |the change in the first static voltage value|-|the change in the second static voltage value|≥the second change threshold, the first pressure sensor and the second pressure sensor are corrected using the third pressure calculation formula; ③ If |the second static voltage value change|-|the first static voltage value change|≥the second change threshold, the first pressure sensor and the second pressure sensor are corrected using the fourth pressure calculation formula.

[0007] Preferably, the default pressure calculation formula is: P=a×Vout / Vcc+b Wherein, P is the clutch pressure, Vout is the output voltage of the clutch pressure sensor, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0008] Preferably, the specific method of correcting the first pressure sensor and the second pressure sensor using the first pressure calculation formula includes: If |the change in the first static voltage value| is greater than or equal to the first change threshold, and |the change in the second static voltage value| is less than the first change threshold, the pressure of the first pressure sensor is corrected according to the following formula: P1=a(Vout1+ΔU1) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant; If |the change in the first static voltage value| is less than the first change threshold, and |the change in the second static voltage value| is greater than or equal to the first change threshold, the pressure of the second pressure sensor is corrected according to the following formula: P2=a(Vout2+ΔU2) / Vcc+b Wherein, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0009] Preferably, the second pressure calculation formula is: P1=a(Vout1+ΔU1) / Vcc+b P2=a(Vout2+ΔU2) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0010] Preferably, the third pressure calculation formula is: P1=a(Vout1+ΔU1) / Vcc+b P2=a(Vout2+ΔU1) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0011] Preferably, the fourth pressure calculation formula is: P1=a(Vout1+ΔU2) / Vcc+b P2=a(Vout2+ΔU2) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0012] Preferably, the value range of the first change threshold is 8±1 mV, and the value range of the second change threshold is 16±1 mV.

[0013] The beneficial effects of the present invention are as follows: A zero drift correction method for a DCT transmission pressure sensor comprises the following steps: 1) Setting a first change threshold and a second change threshold to serve as a basis for correcting the first pressure sensor and the second pressure sensor; 2) reading a basic static voltage value of a first pressure sensor of the DCT transmission and using it as a first basic static voltage value, and reading a basic static voltage value of a second pressure sensor of the DCT transmission and using it as a second basic static voltage value; 3) collecting a voltage value of the first pressure sensor in a static state and using it as a first static voltage value, and collecting a voltage value of the second pressure sensor in a static state and using it as a second static voltage value; 4) Calculating the difference between the first basic static voltage value and the first static voltage value to obtain a change in the first static voltage value; 5) Calculating the difference between the second basic static voltage value and the second static voltage value to obtain a change in the second static voltage value; 6) Correcting the first pressure sensor and the second pressure sensor according to the first change threshold, the second change threshold, the first static voltage value change, and the second static voltage value change.

[0014] By setting two change thresholds and using the static voltage value changes of the two pressure sensors for mutual verification and correction, the present invention can avoid vehicle impact or inability to drive caused by zero drift abnormality of a pressure sensor in the transmission in a negative pressure environment such as high altitude, thereby improving the comfort of the transmission system.

[0015] Preferably, in step 6), the specific manner of correcting the first pressure sensor and the second pressure sensor according to the first change threshold, the second change threshold, the first static voltage value change, and the second static voltage value change includes: 6-1) Calculate the absolute value of the first static voltage value change and the absolute value of the second static voltage value change respectively, and combine them with the first change threshold to correct the first pressure sensor and the second pressure sensor in the following manner: ① If |the change in the first static voltage value| is less than or equal to the first change threshold, and |the change in the second static voltage value| is less than or equal to the first change threshold, the first and second pressure sensors are corrected using the default pressure calculation formula; ② If |the change in the first static voltage value| is greater than the first change threshold, or |the change in the second static voltage value| is greater than the first change threshold, the first pressure sensor and the second pressure sensor are corrected using the first pressure calculation formula; ③ If |the change in the first static voltage value| is greater than the first change threshold, and |the change in the second static voltage value| is greater than the first change threshold, then the first pressure sensor and the second pressure sensor are corrected in combination with the second change threshold; 6-2) Based on the second change threshold, the first pressure sensor and the second pressure sensor are corrected in the following manner: ① If || first static voltage value change|-| second static voltage value change|| < second change threshold, the first pressure sensor and the second pressure sensor are corrected using the second pressure calculation formula; ② If |the change in the first static voltage value|-|the change in the second static voltage value|≥the second change threshold, the first pressure sensor and the second pressure sensor are corrected using the third pressure calculation formula; ③ If |the second static voltage value change|-|the first static voltage value change|≥the second change threshold, the first pressure sensor and the second pressure sensor are corrected using the fourth pressure calculation formula.

[0016] By comparing the first and second change thresholds with the static voltage changes of the two pressure sensors, and correcting the outputs of the pressure sensors based on the comparison results, the present invention can comprehensively cover situations that may occur when a vehicle equipped with a DCT transmission travels from a low altitude to a high altitude. The advantage of the present invention is that it eliminates the need for any additional correction elements. By simply setting multiple change thresholds and multiple pressure calculation formulas, the two existing pressure sensors in the DCT transmission are cross-calibrated, and the clutch pressure is calculated using the pressure calculation formula. This allows correction of the pressure sensor output without increasing vehicle cost, minimizing pressure errors caused by altitude (within the range of 0 to 5000 meters), with the maximum value of the pressure error being no greater than or equal to 0.5 bar. This effectively addresses the issue of reduced pressure sensor output accuracy caused by abnormal zero drift in negative pressure environments such as high altitudes, such as those at high altitudes.

[0017] Glossary DCT transmission: (Dual Clutch Transmission) is a new type of automatic transmission based on the manual transmission. It uses two sets of clutches to control different gears respectively, and works together through the electronic control unit and hydraulic system to realize automatic gear shifting operation of the vehicle.

[0018] Basic static voltage value: This refers to the voltage value exhibited when the system or circuit is in a stable, static state without dynamic changes, such as in power systems or electronic circuits. In this application, this refers to the static voltage value detected by the pressure sensor at the factory (this value is stored internally in the pressure sensor as the basic value). BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the present invention; Figure 2 Schematic diagram of the process of this embodiment. DETAILED DESCRIPTION

[0020] like Figures 1 to 2 As shown, a zero drift correction method for a DCT transmission pressure sensor includes the following steps: 1) Setting a first change threshold and a second change threshold to serve as a basis for correcting the first pressure sensor and the second pressure sensor; 2) reading a basic static voltage value of a first pressure sensor of the DCT transmission and using it as a first basic static voltage value, and reading a basic static voltage value of a second pressure sensor of the DCT transmission and using it as a second basic static voltage value; 3) collecting a voltage value of the first pressure sensor in a static state and using it as a first static voltage value, and collecting a voltage value of the second pressure sensor in a static state and using it as a second static voltage value; 4) Calculating the difference between the first basic static voltage value and the first static voltage value to obtain a change in the first static voltage value; 5) Calculating the difference between the second basic static voltage value and the second static voltage value to obtain a change in the second static voltage value; 6) Correcting the first pressure sensor and the second pressure sensor according to the first change threshold, the second change threshold, the first static voltage value change, and the second static voltage value change.

[0021] According to the above method, the following embodiments are made: 1) Set the first change threshold value to x, i.e., the clutch pressure sensor static value change threshold value, with a range of 8 ± 1 mV; set the second change threshold value to y, i.e., the difference between the two clutch pressure sensor static value change threshold values, with a range of 16 ± 1 mV; In this embodiment, the first and second change thresholds are empirically determined through multiple calibration experiments and serve as a basis for calibration of the first and second pressure sensors. In this embodiment, the ranges of the first and second change thresholds are determined based on the assumption that the driver and passengers experience no noticeable shock during vehicle-wide gear shifting during vehicle calibration experiments.

[0022] It is worth noting that the method of this embodiment is also applicable to the situation where the pressure sensor has zero drift when the external air pressure increases significantly (such as when a vehicle drives from a high-altitude area to a low-altitude area). By simply making appropriate adjustments to the first change threshold, the second change threshold, and the pressure calculation formula, the output result of the pressure sensor can be corrected when the external air pressure increases significantly.

[0023] 2) Read the basic static voltage value U of the first pressure sensor of the DCT transmission (pressure sensor of transmission 1) 01 And as the first basic static voltage value, read the basic static voltage value U of the second pressure sensor of the DCT transmission (pressure sensor of transmission 2) 02 And serve as the second basic static voltage value; 3) Collecting the output voltage value of the clutch 1 pressure sensor (i.e., the first pressure sensor) when the clutch 1 electromagnetic threshold current is 0 mA and using it as the first static voltage value; collecting the output voltage value of the clutch 2 pressure sensor (i.e., the second pressure sensor) when the clutch 2 electromagnetic threshold current is 0 mA and using it as the second static voltage value; 4) Calculating the difference ΔU1 between the first basic static voltage value and the first static voltage value to obtain a change in the first static voltage value; 5) Calculating the difference ΔU2 between the second basic static voltage value and the second static voltage value to obtain a change in the second static voltage value; 6) Correcting the output results of the first pressure sensor and the second pressure sensor according to the first change threshold x, the second change threshold y, the first static voltage value change ΔU1, and the second static voltage value change ΔU2, specifically by: 6-1) Calculate the absolute value of the first static voltage value change ΔU1 and the absolute value of the second static voltage value change ΔU2 respectively, and, in combination with the first change threshold x, correct the output results of the first pressure sensor and the second pressure sensor in the following manner: ① If |the change in the first static voltage value| is less than or equal to the first change threshold, and |the change in the second static voltage value| is less than or equal to the first change threshold, the first and second pressure sensors are corrected using the default pressure calculation formula. In other words, both the first and second pressure sensors can use the default pressure calculation formula to calculate the clutch pressure, thereby correcting the output results. The default pressure calculation formula is: P=a×Vout / Vcc+b Wherein, P is the clutch pressure, Vout is the output voltage of the clutch pressure sensor, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0024] ② If |the change in the first static voltage value| is greater than the first change threshold, or |the change in the second static voltage value| is greater than the first change threshold, the first pressure sensor and the second pressure sensor are corrected using the first pressure calculation formula. Specifically, the correction method includes: If |the change in the first static voltage value| is greater than or equal to the first change threshold, and |the change in the second static voltage value| is less than the first change threshold, the pressure of the first pressure sensor is corrected according to the following formula: P1=a(Vout1+ΔU1) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant; If |the change in the first static voltage value| is less than the first change threshold, and |the change in the second static voltage value| is greater than or equal to the first change threshold, the pressure of the second pressure sensor is corrected according to the following formula: P2=a(Vout2+ΔU2) / Vcc+b Wherein, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0025] ③ If |the change in the first static voltage value| is greater than the first change threshold, and |the change in the second static voltage value| is greater than the first change threshold, then the first pressure sensor and the second pressure sensor are corrected in combination with the second change threshold; 6-2) Based on the second change threshold, the output results of the first pressure sensor and the second pressure sensor are corrected in the following manner: ① If | |first static voltage value change| - |second static voltage value change| | < second change threshold, the first pressure sensor and the second pressure sensor are corrected using the second pressure calculation formula, where the second pressure calculation formula is: P1=a(Vout1+ΔU1) / Vcc+b P2=a(Vout2+ΔU2) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0026] ② If |first static voltage value change|-|second static voltage value change|≥second change threshold, the first pressure sensor and the second pressure sensor are corrected using the third pressure calculation formula, which is: P1=a(Vout1+ΔU1) / Vcc+b P2=a(Vout2+ΔU1) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0027] ③ If |the second static voltage value change|-|the first static voltage value change|≥the second change threshold, the first pressure sensor and the second pressure sensor are corrected using the fourth pressure calculation formula, wherein the fourth pressure calculation formula is: P1=a(Vout1+ΔU2) / Vcc+b P2=a(Vout2+ΔU2) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

[0028] 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 scope of protection of the present invention.

Claims

1. A zero drift correction method for a DCT transmission pressure sensor, characterized in that: The following steps are involved: 1) Setting a first change threshold and a second change threshold to serve as a basis for correcting the first pressure sensor and the second pressure sensor; 2) reading a basic static voltage value of a first pressure sensor of the DCT transmission and using it as a first basic static voltage value, and reading a basic static voltage value of a second pressure sensor of the DCT transmission and using it as a second basic static voltage value; 3) collecting a voltage value of the first pressure sensor in a static state and using it as a first static voltage value, and collecting a voltage value of the second pressure sensor in a static state and using it as a second static voltage value; 4) Calculating the difference between the first basic static voltage value and the first static voltage value to obtain a change in the first static voltage value; 5) Calculating the difference between the second basic static voltage value and the second static voltage value to obtain a change in the second static voltage value; 6) Correcting the first pressure sensor and the second pressure sensor according to the first change threshold, the second change threshold, the first static voltage value change, and the second static voltage value change.

2. The zero drift correction method according to claim 1, characterized in that: In step 6), the specific method of correcting the first pressure sensor and the second pressure sensor according to the first change threshold, the second change threshold, the first static voltage value change, and the second static voltage value change includes: 6-1) Calculate the absolute value of the first static voltage value change and the absolute value of the second static voltage value change respectively, and combine them with the first change threshold to correct the first pressure sensor and the second pressure sensor in the following manner: ① If |the change in the first static voltage value| is less than or equal to the first change threshold, and |the change in the second static voltage value| is less than or equal to the first change threshold, the first and second pressure sensors are corrected using the default pressure calculation formula; ② If |the change in the first static voltage value| is greater than the first change threshold, or |the change in the second static voltage value| is greater than the first change threshold, the first pressure sensor and the second pressure sensor are corrected using the first pressure calculation formula; ③ If |the change in the first static voltage value| is greater than the first change threshold, and |the change in the second static voltage value| is greater than the first change threshold, then the first pressure sensor and the second pressure sensor are corrected in combination with the second change threshold; 6-2) Based on the second change threshold, the first pressure sensor and the second pressure sensor are corrected in the following manner: ① If || first static voltage value change|-| second static voltage value change|| < second change threshold, the first pressure sensor and the second pressure sensor are corrected using the second pressure calculation formula; ② If |the change in the first static voltage value|-|the change in the second static voltage value|≥the second change threshold, the first pressure sensor and the second pressure sensor are corrected using the third pressure calculation formula; ③ If |the second static voltage value change|-|the first static voltage value change|≥the second change threshold, the first pressure sensor and the second pressure sensor are corrected using the fourth pressure calculation formula.

3. The zero drift correction method according to claim 1, characterized in that: The default pressure calculation formula is: P=a×Vout / Vcc+b Wherein, P is the clutch pressure, Vout is the output voltage of the clutch pressure sensor, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

4. The zero drift correction method according to claim 1, characterized in that: The specific method of correcting the first pressure sensor and the second pressure sensor using the first pressure calculation formula includes: If |the change in the first static voltage value| is greater than or equal to the first change threshold, and |the change in the second static voltage value| is less than the first change threshold, the pressure of the first pressure sensor is corrected according to the following formula: P1=a(Vout1+ΔU1) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant; If |the change in the first static voltage value| is less than the first change threshold, and |the change in the second static voltage value| is greater than or equal to the first change threshold, the pressure of the second pressure sensor is corrected according to the following formula: P2=a(Vout2+ΔU2) / Vcc+b Wherein, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

5. The zero drift correction method according to claim 1, characterized in that: The second pressure calculation formula is: P1=a(Vout1+ΔU1) / Vcc+b P2=a(Vout2+ΔU2) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

6. The zero drift correction method according to claim 1, characterized in that: The third pressure calculation formula is: P1=a(Vout1+ΔU1) / Vcc+b P2=a(Vout2+ΔU1) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, ΔU1 is the change in the first static voltage value, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, Vcc is the power supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

7. The zero drift correction method according to claim 1, characterized in that: The fourth pressure calculation formula is: P1=a(Vout1+ΔU2) / Vcc+b P2=a(Vout2+ΔU2) / Vcc+b Wherein, P1 is the pressure of the first clutch, Vout1 is the output voltage of the first pressure sensor, P2 is the pressure of the second clutch, Vout2 is the output voltage of the second pressure sensor, ΔU2 is the change in the second static voltage value, Vcc is the supply voltage of the pressure sensor, a is the first constant, and b is the second constant.

8. The zero drift correction method according to claim 1, characterized in that: The value range of the first change threshold is 8±1 mV, and the value range of the second change threshold is 16±1 mV.

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