An AMT gearbox output shaft speed sensor fault diagnosis method, control unit and vehicle

Abstract

The application relates to the field of signal processing and fault diagnosis of an AMT gearbox output shaft rotating speed sensor, and particularly discloses an AMT gearbox output shaft rotating speed sensor fault diagnosis method, a control unit and a vehicle. According to the vehicle state, a corresponding verification mode is selected to verify the actual output shaft rotating speed collected by the output shaft rotating speed sensor, so as to compare the actual output shaft rotating speed signal with a related signal, and according to the signal difference, the output shaft sensor is predicted and diagnosed for faults. The rotating speed value of the output shaft rotating speed sensor is verified in real time, the corresponding verification mode is selected according to the vehicle state, the verification accuracy is improved, the rotating speed signal abnormality and fault are diagnosed in advance, and the safety of vehicle driving is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of signal processing and fault diagnosis of AMT gearbox output shaft speed sensor, and specifically discloses an AMT gearbox output shaft speed sensor fault diagnosis method, a control unit and a vehicle. BACKGROUND

[0002] The AMT gearbox is a new type of gearbox structure, which adds an electronic control unit on the basis of a traditional manual gearbox to have the advantages of automatic gearbox automatic gear shifting and retain the advantages of manual gearbox, such as high gear transmission efficiency, simple structure and low production cost. The electronic control unit (TCU) of the AMT gearbox collects signals such as engine speed, vehicle speed and clutch, gear shifting actuator position to keep track of the vehicle state at all times. The TCU controls the vehicle in combination with the corresponding signals and control strategies such as engine oil supply, clutch separation and combination, and gearbox gear selection, to achieve the best coordination of the engine, clutch and gearbox.

[0003] The output shaft speed sensor of the AMT gearbox is located at the flange position of the gearbox output shaft to provide the output shaft speed information for the TCU, and generally selects a Hall type or magneto type speed sensor. When the speed sensor is demagnetized, damaged or has unreasonable installation gap, the speed sensor cannot work normally. The TCU relies on the speed information to perform gear selection and shifting operation of the vehicle. If the signal accuracy of the output shaft speed sensor decreases, the vehicle motion state cannot be accurately identified, gear shifting jerk and impact will occur, which greatly reduces the gear shifting quality and affects the driving comfort. If the output shaft speed sensor is damaged or the output speed is abnormal, the vehicle will be prohibited from engaging the step gear, resulting in the vehicle unable to continue driving. The existing output shaft speed sensor diagnosis technology directly judges the signal collected by the sensor. If the signal value is not within the normal measurement range, the sensor is judged to be damaged. This method only diagnoses the signal collected by the output shaft speed sensor itself and cannot diagnose speed abnormality and other conditions, and does not consider the related replacement method after the speed signal is abnormal. Once the sensor is abnormal, the vehicle cannot drive, which exists a driving risk.

[0004] The patent application with publication number CN110173562A discloses a use method of an AMT output shaft speed sensor, which proposes to verify the output shaft speed by calculating the difference between the instrument and ABS, EBS converted speed and the directly measured output shaft speed. This method can diagnose the output shaft speed abnormality, but it does not consider the gear engagement abnormality caused by sudden change of speed, and when the vehicle is in the gear shifting process, the clutch is not fully engaged. The output shaft speed verified by this method is prone to false positives. SUMMARY

[0005] To solve the above problems, the application provides an AMT gearbox output shaft speed sensor fault diagnosis method, a control unit and a vehicle, the speed value of the output shaft speed sensor is verified in real time, and a corresponding verification method is selected according to the vehicle state, the verification accuracy is improved, the abnormality and fault of the speed signal are diagnosed in advance, and the safety of vehicle driving is improved.

[0006] In a first aspect, the technical solution of the application provides an AMT gearbox output shaft speed sensor fault diagnosis method, comprising the following steps:

[0007] Step 1, the pulse signal frequency of the output shaft speed sensor is obtained and converted into a period value, it is detected whether the period value is within the measurement range, if yes, the actual output shaft speed collected by the output shaft speed sensor is calculated according to the period value and step 2 is executed, otherwise, an abnormal fault of the output shaft speed sensor is output and step 4 is executed;

[0008] Step 2, the actual output shaft speed collected by the output shaft speed sensor is verified, if the verification is passed, step 3 is executed, if the verification is not passed, an untrusted fault of the actual output shaft speed is output and step 4 is executed;

[0009] Step 2.1, the gear state, clutch state and vehicle speed of the vehicle are detected;

[0010] Step 2.2, if the detection result meets the first condition, the actual output shaft speed is verified based on the collected speed of the input shaft speed sensor and the intermediate shaft speed sensor, if the detection result meets the second condition, the actual output shaft speed is verified based on the ABS speed;

[0011] Step 3, the actual output shaft speed is used to control the vehicle;

[0012] Step 4, a speed replacement program is started, and the vehicle is controlled by using the replacement speed.

[0013] In an optional embodiment, step 2.2 specifically comprises:

[0014] If the vehicle is not in the shifting process, the gear is not neutral and the vehicle speed is greater than a first preset vehicle speed threshold, the actual output shaft speed is verified based on the collected speed of the input shaft speed sensor and the intermediate shaft speed sensor;

[0015] If the clutch is completely closed and the engine is normal, the actual output shaft speed is verified based on the ABS speed.

[0016] In an optional embodiment, the actual output shaft speed is verified based on the collected speed of the input shaft speed sensor and the intermediate shaft speed sensor, specifically comprising:

[0017] Calculate the first converted output shaft speed V using the following formula. OutputSpeedbyInput ,

[0018]

[0019] In the formula, V InputSpeed For the rotational speed acquired by the input shaft speed sensor, Rat Trans This refers to the gearbox transmission ratio;

[0020] Calculate the second converted output shaft speed V using the following formula. OutputSpeedbyLysft ,

[0021]

[0022] In the formula, V LysftSpeed The rotational speed is collected by the intermediate shaft speed sensor, Rat Constant This is the constant meshing speed ratio;

[0023] Calculate V respectively OutputSpeedbyInput V OutputSpeedbyLysft With V OutputSpeed The difference between them, where V OutputSpeed This refers to the actual output shaft speed;

[0024] If any speed difference exceeds the corresponding speed difference threshold, the verification fails and the actual output shaft speed is deemed unreliable; otherwise, the verification passes and the actual output shaft speed is deemed reliable.

[0025] In one optional implementation, the actual output shaft speed is verified based on the ABS vehicle speed, specifically including:

[0026] Calculate the third converted output shaft speed V using the following formula. Outputspeedclcd ,

[0027]

[0028] In the formula, V abs For the vehicle speed collected by the ABS sensors, Val vton Rd is the conversion factor between vehicle speed and engine speed. Tire The radius of the tire;

[0029] Calculate V OutputSpeedclcd V between OutputSpeed Difference, where V Outputspeed This refers to the actual output shaft speed;

[0030] If the speed difference exceeds the corresponding speed difference threshold, the verification fails and the actual output shaft speed is deemed unreliable; otherwise, the verification passes and the actual output shaft speed is deemed reliable.

[0031] In an optional implementation, the method further includes the following steps:

[0032] Step 0, configuring each rotation speed difference threshold value in a low speed state and a driving state of the vehicle; wherein the low speed state is that the vehicle speed is less than a second preset vehicle speed threshold value, and the driving state is that the vehicle speed is greater than the second preset vehicle speed threshold value;

[0033] After the rotation speed difference is calculated, the vehicle driving state is detected, if the vehicle is in the low speed state, the rotation speed difference threshold value in the state is obtained, if the vehicle is in the driving state, the rotation speed difference threshold value in the state is obtained.

[0034] In an optional embodiment, step 2 further comprises,

[0035] Step 2.3, verifying the actual output shaft rotation speed slope;

[0036] The actual output shaft rotation speed slope K is calculated by the following formula,

[0037]

[0038] In the formula, V OutputSpeed (t) is the rotation speed collected by the output shaft rotation speed sensor in the current period, V OutputSpeed (t-1) is the rotation speed collected by the output shaft rotation speed sensor in the last period, and T is the time of a sampling period;

[0039] If the slope K exceeds the preset slope range, the verification is not passed, it is determined that the actual output shaft rotation speed is not reliable, otherwise the verification is passed, it is determined that the actual output shaft rotation speed is reliable.

[0040] In an optional embodiment, the vehicle is controlled by using the replacement rotation speed, specifically comprising:

[0041] The output shaft sensor rotation speed is replaced by the output shaft rotation speed converted by the ABS vehicle speed or the rotation speed of the odometer sensor.

[0042] In an optional embodiment, step 4 further comprises:

[0043] If the output shaft rotation speed sensor is restored to normal within the preset verification times, the rotation speed replacement is cancelled.

[0044] In a second aspect, the technical scheme of the present application provides an AMT gearbox control unit configured to execute any of the above-mentioned methods.

[0045] In a third aspect, the technical scheme of the present application provides a vehicle configured with the above-mentioned gearbox control unit.

[0046] The AMT gearbox output shaft speed sensor fault diagnosis method, control unit and vehicle provided by the application have the following beneficial effects: the output signal in the working process of the output shaft speed sensor is verified in real time, compared with the related signal, and the output shaft sensor is fault predicted and diagnosed according to the signal difference. The working state of the AMT gearbox can be grasped at any time, the fault is timely warned, the user is reminded to maintain and replace the output shaft speed sensor, the safety and reliability of the AMT gearbox are improved, the vehicle is prevented from having a major problem due to the fault of the output shaft speed sensor, the verification accuracy is improved and the false alarm rate is reduced by detecting the vehicle state and selecting the corresponding verification mode according to the vehicle state. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor based on these drawings.

[0048] Figure 1 It is a flowchart of the AMT gearbox output shaft speed sensor fault diagnosis method provided by the embodiment of the application.

[0049] Figure 2 It is a fault diagnosis architecture schematic diagram of a specific embodiment.

[0050] Figure 3 It is a fault diagnosis flowchart schematic diagram of a specific embodiment. DETAILED DESCRIPTION

[0051] In order to make the person skilled in the art better understand the application scheme, the application will be further described in detail below in combination with the drawings and specific embodiments. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application belongs. The terms used in the specification of the application herein are only for the purpose of describing the specific embodiments and are not intended to limit the application.

[0053] Figure 1is a flowchart of a method for diagnosing faults of an AMT gearbox output shaft speed sensor, according to different requirements, the order of steps in the flowchart can be changed, and some steps can be omitted.

[0054] As shown in the figure, the method comprises the following steps. Figure 1

[0055] S1, acquiring the pulse signal frequency of the output shaft speed sensor and converting it into a period value, detecting whether the period value is within the measurement range, if yes, calculating the actual output shaft speed collected by the output shaft speed sensor according to the period value and performing S2, otherwise outputting an abnormal fault of the output shaft speed sensor and performing S4.

[0056] S2, verifying the actual output shaft speed collected by the output shaft speed sensor, if the verification is passed, performing S3, if the verification is not passed, outputting an untrusted fault of the actual output shaft speed and performing S4.

[0057] S2.1, detecting the gear state, clutch state and vehicle speed of the vehicle.

[0058] S2.2, if the detection result meets the first condition, verifying the actual output shaft speed based on the collected speeds of the input shaft speed sensor and the intermediate shaft speed sensor; if the detection result meets the second condition, verifying the actual output shaft speed based on the ABS speed.

[0059] S3, using the actual output shaft speed to control the vehicle.

[0060] S4, starting a speed replacement program, using the replacement speed to control the vehicle.

[0061] This embodiment mainly includes two aspects of gearbox bottom layer and application layer control for diagnosing faults of the output shaft speed sensor, the gearbox control unit needs to sample the output shaft sensor speed signal in real time, and verify the sampling signal with other related sensor signals to determine whether the output shaft sensor is abnormal, if so, the speed needs to be replaced, and the user is prompted to maintain or replace the sensor in time. First, the signal is diagnosed through the controller bottom layer, that is, whether the sampling frequency of the output shaft speed sensor is within a reasonable range is directly detected, and then the actual output shaft speed is further verified through the controller application layer, and the verification process selects different verification forms according to the vehicle state to improve the verification accuracy.

[0062] To further understand the present application, a specific embodiment is provided below to further illustrate the present application, Figure 2 ​is a schematic diagram of a fault diagnosis architecture of the embodiment, and first, the controller bottom layer directly diagnoses the signal fault of the output shaft speed sensor. After the fault diagnosis passes, the output shaft speed sensor signal is input to the controller application layer through the controller bottom layer, and further speed verification is performed. The application layer judges whether the speed is abnormal through the following three ways. One is to verify through other speed sensor signals, two is to judge through the ABS sensor vehicle speed signal value, and three is to judge through the slope value of the output shaft sensor in the sampling period. When one of the verification methods does not pass, the transmission controller reports an output shaft sensor speed untrustworthy fault. Among them, method one and method two correspond to different vehicle states, and the verification method is selected under the condition of meeting the corresponding vehicle state. The embodiment can greatly ensure the comfort of vehicle shifting, avoid the phenomenon of gear shifting jerk and impact of the vehicle, and reduce the driving experience of the user. At the same time, when the transmission control unit receives an output shaft abnormality or an output shaft sensor speed signal untrustworthy fault, the speed replacement function is activated. According to different working conditions of the vehicle, the ABS speed and the speedometer speed signal are selected to replace the speed to ensure that the vehicle can normally drive.

[0063] Figure 3 is a schematic diagram of a fault diagnosis process of the embodiment, as shown in Figure 3 The embodiment specifically includes the following steps.

[0064] SS1, the controller bottom layer software performs direct collection of the output shaft speed sensor signal value rationality judgment.

[0065] When a gear of the transmission gear passes through the sensor, a pulse signal will be generated, and the controller bottom layer judges whether the collected periodic pulse is within a reasonable range. If yes, the periodic signal is converted into a speed signal; otherwise, the user is prompted that the output shaft sensor is abnormal at this time, and the sensor installation gap needs to be checked, and whether the sensor itself is damaged or there is a demagnetization phenomenon.

[0066] Specifically, when the output shaft gear rotates, each tooth on the gear passes through the speed sensor probe, which generates a voltage pulse. The frequency of this voltage pulse is proportional to the gear speed, and the controller bottom layer software converts the collected pulse signal frequency into a period value and performs rationality verification. If the signal period value is out of the measurement range of the speed sensor, an output shaft sensor fault is reported.

[0067] If the signal period is within a reasonable range, the collected periodic signal is converted into a speed signal through the following formula.

[0068]

[0069] Num TeethN is the number of teeth of the output shaft, T0 is the period of the output shaft speed sensor, V OutputSpeed is the actual output shaft speed. It can be understood that the actual output shaft speed is the output shaft speed actually collected by the output shaft speed sensor.

[0070] SS2, the controller application layer verifies the actual output shaft speed.

[0071] Verifying the actual output shaft speed includes conversion by other speed sensor values, ABS vehicle speed conversion, and the slope value of the output shaft sensor speed itself.

[0072] First, the gear state, clutch state and vehicle speed of the vehicle are detected. If the vehicle is not in the process of shifting, the gear is not neutral, and the vehicle speed is greater than a first preset vehicle speed threshold (such as 10 km / h), the actual output shaft speed is verified based on the collected speeds of the input shaft speed sensor and the intermediate shaft speed sensor. If the clutch is fully closed and the engine is not abnormal, the actual output shaft speed is verified based on the ABS speed.

[0073] SS2.1, verifying the actual output shaft speed based on the collected speeds of the input shaft speed sensor and the intermediate shaft speed sensor.

[0074] When verifying the output shaft speed by other speed sensors, it is necessary to exclude the case where the sensor speed does not meet the corresponding transmission rule, including when the vehicle is in the process of shifting and when the gear is neutral. The other speed sensors of this specific embodiment are the input shaft speed sensor and the intermediate shaft speed sensor.

[0075] SS2.1.1, the first converted output shaft speed V OutpSutSpeedbyInput is calculated using the following formula

[0076]

[0077] where V InputSpeed is the speed collected by the input shaft speed sensor, Rat Trans is the transmission speed ratio of the gearbox.

[0078] SS2.1.2, the second converted output shaft speed V OutputSpeedbyLysft is calculated using the following formula

[0079]

[0080] where V LysftSpeed is the speed collected by the intermediate shaft speed sensor, Rat Constant is the constant meshing speed ratio.

[0081] SS2.1.3, V OutputSpeedbyInput , V OutputSpeedbyLysft and VOutputspeed the difference between V OutputSpeed is the actual output shaft speed.

[0082] SS2.1.4, if any of the speed difference values exceeds the corresponding speed difference value threshold, the verification fails, and it is determined that the actual output shaft speed is not reliable, otherwise the verification passes, and it is determined that the actual output shaft speed is reliable.

[0083] SS2.2, verifying the actual output shaft speed based on the ABS vehicle speed.

[0084] When the clutch is fully engaged and the engine is not abnormal, the ABS vehicle speed can be used for output shaft sensor verification.

[0085] SS2.2.1, the third converted output shaft speed V OutputSpeedclcd is calculated using the following formula:

[0086]

[0087] In the formula, V abs is the vehicle speed collected by the ABS sensor, Val vton is the vehicle speed to speed conversion coefficient, and Rd Tire is the tire radius.

[0088] For example, Val vton = 30 / 3.6 is the conversion relationship between vehicle speed and speed.

[0089] SS2.2.2, the difference between V OutputSpeedclcd and V Outputspeed is calculated, where V OutputSpeed is the actual output shaft speed.

[0090] SS2.2.3, if the speed difference value exceeds the corresponding speed difference value threshold, the verification fails, and it is determined that the actual output shaft speed is not reliable, otherwise the verification passes, and it is determined that the actual output shaft speed is reliable.

[0091] In this specific embodiment, considering that when the vehicle is in the coasting state, the vehicle speed is low and does not reach the minimum recognition speed of the sensor, when the speed is replaced, the vehicle state needs to be distinguished, and the speed difference value judgment when coasting is correspondingly increased. Specifically, before fault diagnosis, the speed difference value threshold of each vehicle in the low speed state and the driving state is configured; the low speed state is that the vehicle speed is less than a second preset vehicle speed threshold, and the driving state is that the vehicle speed is greater than the second preset vehicle speed threshold. After calculating the speed difference value, the vehicle driving state is detected, if the vehicle is in the low speed state, the speed difference value threshold in this state is obtained, if the vehicle is in the driving state, the speed difference value threshold in this state is obtained.

[0092] SS2.3, verifying the slope of the actual output shaft speed.

[0093] SS2.3.1, the actual output shaft speed slope K is calculated by the following formula,

[0094]

[0095] V (t) - V (t-1) T OutputSpeed V (t) is the current cycle collected speed of the output shaft speed sensor, V OutputSpeed V (t-1) is the last cycle collected speed of the output shaft speed sensor, and T is the time of a sampling period.

[0096] SS2.3.2, if the slope K exceeds the preset slope range, the verification fails, it is determined that the actual output shaft speed is not reliable, otherwise the verification passes, and it is determined that the actual output shaft speed is reliable.

[0097] It can be understood that if the slope is too large, it means that the output shaft speed signal collected at this time has a sudden change, and the user needs to be prompted that the current output shaft speed is not reliable.

[0098] SS3, the output shaft speed is replaced.

[0099] After activating the output shaft sensor fault and the speed signal unreliable abnormal warning, the output shaft speed needs to be replaced. This embodiment selects the ABS speed converted to the output shaft speed or the odometer sensor speed to replace the output shaft signal. According to different working conditions of the vehicle, the ABS speed and the odometer speed signal can be selected to replace the speed to ensure that the vehicle can run normally.

[0100] If the output shaft speed sensor returns to normal within the preset verification times, the speed replacement is cancelled. Specifically, after the corresponding driving cycle, the controller will continue to judge the signal state of the output shaft speed sensor. If the signal is continuously abnormal, the user needs to be prompted to repair and replace the sensor in time. If the sensor signal is a transient abnormality, the speed sensor abnormal warning prompt can be cleared after the corresponding driving cycle times are judged, and the output shaft speed sensor signal is used to control the AMT gearbox selection, gear shifting, clutch and other control strategies.

[0101] The embodiment provides an AMT gearbox control unit configured to execute the AMT gearbox output shaft speed sensor fault diagnosis method of the above embodiment.

[0102] The embodiment provides a vehicle configured with the AMT gearbox control unit of the above embodiment.

[0103] The above disclosed are only the preferred embodiments of the present application, but the present application is not limited thereto, any non-creative changes and several improvements and refinements made by any person skilled in the art without departing from the principles of the present application shall fall within the protection scope of the present application.

Claims

1. A method for diagnosing faults in the output shaft speed sensor of an AMT transmission, characterized in that, Includes the following steps: Step 1: Obtain the pulse signal frequency of the output shaft speed sensor and convert it into a period value. Check whether the period value is within the measurement range. If it is, calculate the actual output shaft speed collected by the output shaft speed sensor based on the period value and execute Step 2. Otherwise, output the output shaft speed sensor as abnormal and execute Step 4. Step 2: Verify the actual output shaft speed collected by the output shaft speed sensor. If the verification passes, proceed to Step 3. If the verification fails, output an unreliable actual output shaft speed fault and proceed to Step 4. Step 2.1: Check the vehicle's gear position, clutch status, and vehicle speed; Step 2.2: If the detection result meets the first condition, the actual output shaft speed is verified based on the speeds collected by the input shaft speed sensor and the intermediate shaft speed sensor; if the detection result meets the second condition, the actual output shaft speed is verified based on the ABS vehicle speed. Step 3: Control the vehicle using the actual output shaft speed; Step 4: Start the speed replacement program and use the replacement speed to control the vehicle; Step 2.2 specifically includes: If the vehicle is not in the process of shifting gears, the gear is not in neutral, and the vehicle speed is greater than the first preset vehicle speed threshold, the actual output shaft speed is verified based on the speed collected by the input shaft speed sensor and the intermediate shaft speed sensor. If the clutch is fully engaged and the engine is functioning normally, the actual output shaft speed is verified based on the ABS vehicle speed. The actual output shaft speed is verified based on the speeds collected by the input shaft speed sensor and the intermediate shaft speed sensor, specifically including: Calculate the first converted output shaft speed using the following formula. , In the formula, The input shaft speed sensor collects the rotational speed. This refers to the gearbox transmission ratio; Calculate the second converted output shaft speed using the following formula. , In the formula, The rotational speed is collected by the intermediate shaft speed sensor. This is the constant meshing speed ratio; Calculate separately , and The difference between them, where This refers to the actual output shaft speed; If any speed difference exceeds the corresponding speed difference threshold, the verification fails and the actual output shaft speed is deemed unreliable; otherwise, the verification passes and the actual output shaft speed is deemed reliable.

2. The method for diagnosing faults in the output shaft speed sensor of an AMT transmission according to claim 1, characterized in that, The actual output shaft speed is verified based on the ABS vehicle speed, specifically including: Calculate the third converted output shaft speed using the following formula. , In the formula, The vehicle speed is collected by the ABS sensor. This is the conversion coefficient between vehicle speed and engine speed. The radius of the tire; calculate and The difference between them, where This refers to the actual output shaft speed; If the speed difference exceeds the corresponding speed difference threshold, the verification fails and the actual output shaft speed is deemed unreliable; otherwise, the verification passes and the actual output shaft speed is deemed reliable.

3. The method for diagnosing faults in the output shaft speed sensor of an AMT transmission according to claim 1 or 2, characterized in that, The method also includes the following steps: Step 0: Configure the threshold values ​​for the speed difference between the vehicle in low-speed state and driving state; where the low-speed state is when the vehicle speed is less than the second preset vehicle speed threshold, and the driving state is when the vehicle speed is greater than the second preset vehicle speed threshold. After calculating the speed difference, the vehicle's driving status is detected. If the vehicle is in a low-speed state, the speed difference threshold for that state is obtained; if the vehicle is in a driving state, the speed difference threshold for that state is obtained.

4. The method for diagnosing faults in the output shaft speed sensor of an AMT transmission according to any one of claims 1-3, characterized in that, Step 2 also includes, Step 2.3: Verify the slope of the actual output shaft speed; The slope K of the actual output shaft speed is calculated using the following formula. K= In the formula, The output shaft speed sensor collects the rotational speed in the current cycle. The output shaft speed sensor collects the speed in the previous cycle, and T is the time of one sampling cycle. If the slope K exceeds the preset slope range, the verification fails and the actual output shaft speed is deemed unreliable; otherwise, the verification passes and the actual output shaft speed is deemed reliable.

5. The method for diagnosing faults in the output shaft speed sensor of an AMT transmission according to claim 4, characterized in that, Using alternative speed control for the vehicle specifically includes: The output shaft speed is replaced by the output shaft sensor speed, which is calculated from the ABS vehicle speed or the speed of the odometer sensor.

6. The method for diagnosing faults in the output shaft speed sensor of an AMT transmission according to claim 5, characterized in that, Step 4 also includes: If the output shaft speed sensor returns to normal within the preset number of calibrations, then the speed replacement will be cancelled.

7. An AMT transmission control unit, characterized in that, Configured to perform the method described in any one of claims 1-6.

8. A vehicle, characterized in that, It is equipped with the gearbox control unit as described in claim 7.

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