A transfer case shift control method with gear position redundant signals

Abstract

The present invention provides a transfer case shift control method with gear position redundant signals, comprising the following steps: S100, determining whether there is a fault in the transfer case control system. If there is a fault, step S200 is executed; otherwise, step S300 is executed; S200, determining whether it is a motor position fault. If so, enter the position diagnosis program; otherwise, record the fault code and perform corresponding processing; S300, determining whether the transfer case is in gear. If it is in gear, step S400 is executed; otherwise, enter the position self-learning mode; S400, determining whether the transfer case gear position is consistent with the switch required gear position. If they are consistent, the program ends; otherwise, enter the normal shift mode and the program ends. According to the transfer case shift control method with gear position redundant signals of the embodiments of the present invention, based on the dual gear signals, the robustness of the system is improved, it is convenient to diagnose the fault type, find out the fault location, reduce the after-sales workload. At the same time, the adverse effects caused by occasional faults to users are reduced, and the user experience is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and particularly relates to a transfer case shift control method with gear position redundant signals. Background Art

[0002] Generally, four-wheel drive vehicles are equipped with a transfer case to meet the requirements of two-wheel drive and four-wheel drive transmissions. Transfer cases are generally divided into three types: part-time four-wheel drive, on-demand four-wheel drive, and full-time four-wheel drive. The ways for the transfer case to achieve four-wheel drive include gear drive and sprocket drive, and the vast majority of transfer cases use sprocket drive. The part-time four-wheel drive transfer case generally has three gears: 2H, 4H, and 4L. Generally, the 2H gear is for rear-wheel drive, the 4H gear is for four-wheel high-speed drive, and the 4L gear is for four-wheel low-speed drive. The part-time transfer case is divided into manual shift and manual electric control shift according to the shift method. The electric control part-time transfer case is a common type of transfer case installed in off-road vehicles. When shifting the electric control part-time transfer case, the driver manipulates the four-wheel drive switch to send the shift signal to the transfer case control unit. The transfer case control unit judges whether there is a fault and whether the shift condition is met. When the shift condition is met, the transfer case control unit drives the shift motor to rotate to reach the target gear, and the motor stops rotating.

[0003] Generally, the position where the transfer case shift motor rotates is realized by the motor position encoder. The problems existing in this kind of shift system are as follows: The motor position signal failure may cause the signal to be unrecognizable, the motor cannot shift gears, and the display instrument gives a false alarm, seriously affecting the customer experience; if a signal failure occurs during the shift process, it will also lead to unpredictable risks; in addition, it is difficult to troubleshoot the motor position failure. Summary of the Invention

[0004] The technical problem to be solved in the embodiment of the present invention is that when the motor has an occasional instantaneous failure, it is difficult to judge the cause of the failure, which affects normal shifting and the user experience.

[0005] In view of this, the present invention provides a transfer case shift control method with gear position redundant signals.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The transfer case shift control method with gear position redundant signals according to the embodiment of the present invention includes the following steps:

[0008] S100. Judge whether there is a fault in the transfer case control system. If there is a fault, execute step S200; otherwise, execute step S300;

[0009] S200. Judge whether it is a motor position fault. If so, enter the position diagnosis program; otherwise, record the fault code and perform corresponding processing;

[0010] S300. Determine whether the transfer case is in gear. If it is in gear, execute step S400; otherwise, enter the position self-learning mode.

[0011] S400. Determine whether the transfer case gear position is consistent with the switch required gear position. If they are consistent, the program ends; otherwise, enter the normal gear shifting mode and the program ends.

[0012] The transfer case gear shifting control method with redundant gear position signals according to the embodiment of the present invention may further include the following technical features:

[0013] Further, in step S200, the entering the position diagnosis program includes the following steps:

[0014] S210. Determine whether the transmission is in the N gear. If it is, execute step S220; otherwise, prompt and wait for the transmission to be in the N gear.

[0015] S220. Control the motor to rotate in the direction of the 2H gear position, and prompt the transfer case for self-diagnosis.

[0016] S230. When the motor rotates to the 2H gear position, stop rotating, and determine whether the current motor code is the designed value. If it is, execute step S240; otherwise, execute step S250.

[0017] S240. Determine whether the number of motor code matching values is less than the set number. If it is, enter the position self-learning mode; otherwise, enter the normal gear shifting mode and rotate according to the switch required gear position.

[0018] S250. Enter the fault diagnosis mode.

[0019] Further, in step S300, the position self-learning mode includes the following steps:

[0020] S310. Control the motor to rotate in the direction of the 4L gear position, record the sequentially appeared motor code values and gear position switch values, and prompt the transfer case for self-diagnosis.

[0021] S320. Compare the motor code value and the gear position switch value with the designed value to determine whether they match. If they do, execute step S330; otherwise, enter the fault type confirmation mode.

[0022] S330. Determine whether the motor has stopped rotating. If it has stopped, execute step S340; otherwise, under the condition that the number of matching values is less than the set number, the motor continues to rotate. When the number of matching values is not less than the set value, the motor stops rotating and enters the normal gear shifting mode.

[0023] S340. Determine whether the number of motor code matching values is less than the set number. If it is, enter the attempt gear shifting mode; otherwise, enter the normal gear shifting mode and rotate according to the switch required gear position.

[0024] Further, in step S250, the fault diagnosis mode includes the following steps:

[0025] S251. Determine whether the motor has completed rotating in the direction of the 2H gear. If so, execute step S252; otherwise, control the motor to rotate in the direction of the 2H gear, record the sequentially appeared motor code values and gear position switch values, and execute step S252;

[0026] S252. Determine whether the number of fault code values that match is less than the set number. If less, execute step S253; otherwise, enter the fault type confirmation mode;

[0027] S253. Control the motor to rotate in the direction of the 4L gear, record the sequentially appeared motor code values, and determine whether the number of fault code values that match is less than the set number. If so, prompt a gear shifting fault and prohibit gear shifting; otherwise, enter the fault type confirmation mode.

[0028] Further, in step S320, the fault type confirmation mode includes the following steps:

[0029] S321. Determine whether the switch combination value is consistent with the designed value. If so, enter the function degradation gear shifting mode; otherwise, prompt a position sensor fault and prohibit gear shifting.

[0030] Further, the function degradation gear shifting mode includes:

[0031] Use the gear position switch signal as the gear position signal to control the transfer case to shift gears; and prompt a motor position fault.

[0032] Further, in the step S400, the normal gear shifting mode includes:

[0033] S410. Receive the four-wheel drive switch gear position demand signal and compare it with the current gear position of the transfer case;

[0034] S420. Determine whether to enter the normal gear shifting mode according to the vehicle state signal.

[0035] The above technical solution of the present invention has at least the following technical effects:

[0036] According to the transfer case gear shifting control method with redundant gear position signals in the embodiment of the present invention, based on the dual gear position signals, the robustness of the system is improved, the fault type is easy to diagnose, the fault location is found, the after-sales workload is reduced. At the same time, the adverse effects caused by occasional faults to users are reduced, and the user experience is improved. Brief Description of the Drawings

[0037] Figure 1Flow chart of the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of the transfer case motor position encoder disk structure in the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention;

[0039] Figure 3 Flow chart of the position diagnosis program in the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention;

[0040] Figure 4 Flow chart of the position self - learning mode in the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention;

[0041] Figure 5 Flow chart of the fault diagnosis mode in the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention;

[0042] Figure 6 Flow chart of the fault type confirmation mode in the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention;

[0043] Figure 7 Flow chart of entering the normal shift mode in the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention.

[0044] Reference numerals

[0045] Motor position encoder 1. Detailed implementation manners

[0046] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0047] The transfer case shift control method with gear position redundant signals according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings first.

[0048] As Figure 1 shown, the transfer case shift control method with gear position redundant signals according to an embodiment of the present invention includes the following steps:

[0049] S100. Judge whether there is a fault in the transfer case control system. If there is a fault, execute step S200; otherwise, execute step S300;

[0050] S200. Determine whether there is a motor position fault. If so, enter the position diagnosis program; otherwise, record the fault code and perform corresponding processing;

[0051] S300. Determine whether the transfer case is in gear. If it is in gear, execute step S400; otherwise, enter the position self - learning mode;

[0052] S400. Determine whether the transfer case gear position is consistent with the switch - required gear position. If it is consistent, the program ends; otherwise, enter the normal gear - shifting mode and the program ends.

[0053] Specifically, the position where the transfer case shift motor rotates is usually achieved through the motor position encoder 1. As Figure 2 shown, there are multiple concentric discontinuous sector rings on the motor position encoder 1. One of the five pins of the motor position encoder 1, pin P0, is grounded, and the other four pins, P1, P2, P3, and P4, are connected to or disconnected from the ground loop through the sector rings. In this way, at different positions, the four pins each contact different rings. If the pin is grounded as 0 and floating as 1, then at the same position, a group of codes appears for the four different pin values, and the codes are different at different positions (there can also be the same values at intervals). The principle of the shift motor position encoder 1 is simple and the cost is low, so it has been widely used.

[0054] When the transfer case control unit controls the shift motor to shift gears, the motor drives the motor position encoder 1 to rotate. When the motor position encoder 1 rotates to different positions, the control unit reads different coding information to identify the gear position. Usually, it is determined whether the transfer case needs to shift gears based on the state of the whole vehicle, the position of the four - wheel drive operation switch, and the motor position. When the actual position of the transfer case corresponding to the motor position of the transfer case does not match the gear position required by the four - wheel drive operation switch, a gear shift is performed. Therefore, it is crucial whether the position signal of the transfer case shift motor reflects the actual position of the transfer case gear.

[0055] In the encoder scheme of the motor position encoder 1, any open - circuit or ground - short - circuit fault in any signal line will cause the control unit to be unable to identify the motor position, resulting in the inability to shift gears. In particular, if the signal coding after the fault is the same as the signal coding without fault, especially if several consecutive codings are the same, but actually not at the same position, in this case, the control unit cannot identify, and the transfer case control unit controlling the shift motor to shift gears may pose a danger to the vehicle.

[0056] Therefore, in order to meet the increasingly high safety requirements, a sensor for detecting the actual gear position signal of the transfer case is added. Such a sensor can be a Hall sensor, a gear position switch signal, etc. Since there is a rigid connection between the transfer case shift motor and the shift mechanism, the encoded signal represents the shift position of the transfer case. However, if a fault occurs in the shift mechanism, the motor rotates and the encoding changes, but the actual position of the shift mechanism may not change. The newly added sensor for detecting the gear position of the transfer case is usually directly arranged on the shift mechanism and is not affected by the system fault between the motor and the shift mechanism. Therefore, this signal can be used to judge the actual position of the shift mechanism.

[0057] The present invention is to solve the problem of judging the cause of the fault of the shift system and taking measures to better realize the shift control of the transfer case when adding a sensor for detecting the gear position of the transfer case.

[0058] That is to say, the present invention establishes an initial shift control method based on dual gear signals. When the vehicle is powered on and the transfer case control unit is initialized, the system is self-checked to judge whether there is a fault: if there is a fault, it is judged whether it is a motor position fault. If it is a motor fault, it enters the position diagnosis program. If there is no fault, it is judged whether the transfer case is in gear. If it is not in gear, it enters the position self-learning mode.

[0059] Further, the transfer case control unit TCCU reads the four-wheel drive command gear position. This command gear position comes from the four-wheel drive operation switch or the actual gear position of the transfer case stored when the other system last powered off. This signal will be used as the gear position demand of the transfer case. In step S400, when the current motor position of the transfer case read by the TCCU is a certain gear position among 2H\4H\4L and is consistent with the command gear position requirement, it enters the waiting shift state; when the current motor position of the transfer case read by the TCCU is inconsistent with the received command gear position requirement, a gear self-switching is required and it enters the normal shift program. During normal shifting, the motor position encoding is used as the target position for control. When the gear position switch and the motor position encoding are both in place, a shift-to-gear signal is sent to the instrument panel. This shift method judges the fault step by step in different cases, finds out the possible fault positions and fault types, and decides whether to continue shifting or report a fault, improving the accuracy of fault judgment, avoiding the influence of the transfer case motor position encoder harness fault or occasional harness poor contact on the normal shifting of the transfer case, and at the same time, avoiding directly feedbacking the occasional fault signal without further judgment to the customer, which affects the customer experience. In addition, in the case of normal shifting, the transfer case motor encoding value is stored in the non-volatile storage area of the transfer case controller. At the same time, the transfer case encoding values that may have various faults are also stored in the non-volatile storage area of the transfer case controller.

[0060] Therefore, according to the transfer case shift control method with gear position redundant signals according to the embodiments of the present invention, based on the dual gear position signals, the robustness of the system is improved, which is convenient for diagnosing the type of fault, finding out the fault location, reducing the after-sales workload. At the same time, the adverse effects caused by occasional faults to users are reduced, and the user experience is improved.

[0061] According to an embodiment of the present invention, as Figure 3 shown, in step S200, entering the position diagnosis program includes the following steps:

[0062] S210. Determine whether the transmission is in the N gear. If so, execute step S220; otherwise, prompt and wait for the transmission to be in the N gear;

[0063] S220. Control the motor to rotate in the direction of the 2H gear position, and prompt the transfer case for self-diagnosis;

[0064] S230. When the motor rotates to the 2H gear position, stop rotating, and determine whether the current motor code is the designed value. If so, execute step S240; otherwise, execute step S250;

[0065] S240. Determine whether the number of motor code matching values is less than the set number. If so, enter the position self-learning mode; otherwise, enter the normal shift mode and rotate according to the switch demand gear position;

[0066] S250. Enter the fault diagnosis mode.

[0067] Specifically, the specific steps of the position diagnosis program are as follows: The TCCU confirms whether the automatic transmission is currently in the N gear. If it is not in the N gear, a prompt of "Enter the motor position diagnosis, please put the automatic transmission in the N gear" is sent through the instrument, and at this time, the transmission is put in the N gear. If it is in the N gear, the shift motor is controlled to rotate in the direction of the 2H gear position, and a prompt of "Transfer case self-diagnosis, please wait" is sent through the instrument. After the motor cannot rotate, the current motor code value is compared with the stored theoretical value. If the value does not exist, it indicates that the motor is stuck and enters the fault diagnosis mode. If the value exists and the number of motor code matching values is less than the set number, enter the position self-learning mode to judge the fault in advance; otherwise, enter the normal shift mode.

[0068] According to an embodiment of the present invention, as Figure 4 shown, in step S300, the position self-learning mode includes the following steps:

[0069] S310. Control the motor to rotate in the direction of the 4L gear position, record the sequentially appeared motor code values and gear position switch values, and prompt the transfer case for self-diagnosis;

[0070] S320. Compare the motor coding value and the gear position switch value with the designed values to determine whether they match. If so, execute step S330; otherwise, enter the fault type confirmation mode.

[0071] S330. Determine whether the motor has stopped rotating. If it has, execute step S340; otherwise, under the condition that the number of matching values is less than the set value, the motor continues to rotate. When the number of matching values is not less than the set value, the motor stops rotating and enters the normal gear shifting mode.

[0072] S340. Determine whether the number of motor coding matching values is less than the set value. If so, enter the attempt gear shifting mode; otherwise, enter the normal gear shifting mode and rotate according to the switch required gear position.

[0073] In other words, the specific steps of the position self - learning mode are as follows: First, control the motor to rotate in the direction of the 4L gear position, record the sequentially appeared coding values and gear position switch values or signals with equivalent functions (if any), and at the same time prompt "transfer case self - diagnosis" through the instrument, and compare the coding values and gear position switch values with the designed values (in the case of no fault). If there are unmatched values, enter the fault type confirmation mode; otherwise, under the condition that the number of matching values is less than the set value, the motor continues to rotate. When the number of matching values is not less than the set value, the motor stops rotating and enters the normal gear shifting mode, and control the motor to rotate towards the gear position matching the four - wheel drive control switch.

[0074] If the motor stops rotating and the number of motor coding matching values is less than the set value, enter the attempt gear shifting program. If successful, enter the normal gear shifting; if not successful, enter the 2H gear and prompt gear shifting failure. Among them, the number of set values depends on the transfer case coding design scheme and generally can be taken as 6. If the motor stops rotating and the number of motor coding matching values is not less than the set value, enter the normal gear shifting mode and rotate according to the switch required gear position.

[0075] In an embodiment of the present invention, as Figure 5 shown, in step S250, the fault diagnosis mode includes the following steps:

[0076] S251. Determine whether the motor has completed rotating in the direction of the 2H gear position. If so, execute step S252; otherwise, control the motor to rotate in the direction of the 2H gear position, record the sequentially appeared motor coding values and gear position switch values, and execute step S252.

[0077] S252. Determine whether the number of matching fault coding values is less than the set value. If less, execute step S253; otherwise, enter the fault type confirmation mode.

[0078] S253. Control the motor to rotate in the direction of the 4L gear position, record the motor code values that appear in sequence, and determine whether the number of matching fault code values is less than the set value. If so, prompt a shifting fault and prohibit shifting; otherwise, enter the fault type confirmation mode.

[0079] That is to say, the fault diagnosis mode is to compare the sequence code values that appear in sequence with the stored theoretical fault values to determine whether it is a shifting fault or further fault type confirmation is required.

[0080] In an embodiment of the present invention, in step S320, as Figure 6 shown, the fault type confirmation mode includes the following steps:

[0081] S321. Determine whether the switch combination value is consistent with the design value. If so, enter the function degradation shifting mode; otherwise, prompt a position sensor fault and prohibit shifting.

[0082] In other words, in the table corresponding to the fault type, check whether the gear position switch combination values that appear in sequence are consistent with the design values. If they are consistent, enter the function degradation shifting mode, which does not affect normal shifting; if they are inconsistent, display a transfer case position sensor fault and prohibit shifting.

[0083] It should be noted that when a certain fault occurs, what code value the control unit reads out, and what values are read out when various types of faults occur, these values are all stored in the non-volatile memory of the control unit. Matching means that the code value read out by the control unit is consistent with the numerical value and the number of codes in the stored value. Mismatching means that the code value read out by the control unit is consistent with the numerical value in the stored value, but the number read out is less than the number of codes set in the storage.

[0084] Preferably, the function degradation shifting mode includes: using the gear position switch signal as the gear position signal to control the transfer case to shift gears; and outputting an instrument prompt for a motor position fault.

[0085] Specifically, the function degradation shifting mode includes: using the gear position switch signal as the gear position signal to control the transfer case to shift gears; storing a motor position fault, and the instrument prompts "There is a fault in the motor position. The current is in the function degradation mode. It is recommended to eliminate the fault as soon as possible."

[0086] Further, in step S400, as Figure 7 shown, entering the normal shifting mode includes:

[0087] S410. Receive the four-wheel drive switch gear position demand signal and compare it with the current gear position of the transfer case;

[0088] S420. Determine whether to enter the normal shifting mode according to the vehicle state signal.

[0089] In other words, the shift control method includes receiving the four-wheel drive switch gear position demand signal, comparing it with the current gear position of the transfer case, and determining whether the transfer case shifts gears according to the vehicle state. The vehicle state includes vehicle speed, four-wheel drive operation switch position, transmission gear position, and other system states of the vehicle. In addition, it may further include the following function: the interaction between the control unit and the instrument, that is, when the shift condition is not met, a shift reminder is given.

[0090] In summary, according to the transfer case shift control method with redundant gear signals of the embodiments of the present invention, based on the dual gear signals, when an accidental instantaneous failure occurs in the motor position signal, the actual state of the transfer case is determined according to the other gear signal, without interfering with the user through the instrument, improving the robustness of the system, facilitating the diagnosis of the fault type, finding the fault location, reducing the after-sales workload. At the same time, the adverse impact on the user caused by accidental faults is reduced, and the user experience is improved.

[0091] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the art to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right" are only used to represent relative position relationships, and when the absolute position of the object being described changes, the relative position relationship also changes accordingly.

[0092] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art of the present technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A transfer case shift control method with redundant gear position signals, characterized in that, It includes the following steps: S100. Determine whether there is a fault in the transfer case control system. If there is a fault, execute step S200; Otherwise, execute step S300; S200. Determine whether it is a motor position fault. If so, enter the position diagnosis program; otherwise, record the fault code and perform corresponding processing; S300. Determine whether the transfer case is in gear. If it is in gear, execute step S400; otherwise, enter the position self-learning mode; S400. Determine whether the transfer case gear position is consistent with the switch required gear position. If they are consistent, the program ends; Otherwise, enter the normal shifting mode and the program ends; Among them, in step S300, the position self-learning mode includes the following steps: S310. Control the motor to rotate in the direction of the 4L gear position, record the motor code values and gear switch values that appear in sequence, and prompt the transfer case for self-diagnosis; S320. Compare the motor code values and gear switch values with the design values to determine whether they match. If they match, execute step S330; otherwise, enter the fault type confirmation mode; S330. Determine whether the motor has stopped rotating. If it has stopped, execute step S340; otherwise, under the condition that the number of matching values is less than the set value, the motor continues to rotate. When the number of matching values is not less than the set value, the motor stops rotating and enters the normal shifting mode; S340. Determine whether the number of motor code matching values is less than the set value. If so, enter the attempt shifting mode; otherwise, enter the normal shifting mode and rotate according to the switch required gear position.

2. The transfer case shift control method with a gear position redundant signal according to claim 1, wherein, In step S200, the entering the position diagnosis program includes the following steps: S210. Determine whether the transmission is in the N gear position. If so, execute step S220; otherwise, prompt and wait for the transmission to be in the N gear position; S220. Control the motor to rotate in the direction of the 2H gear position and prompt the transfer case for self-diagnosis; S230. When the motor rotates to the 2H gear position, stop rotating, and determine whether the current motor code is the design value. If so, execute step S240; otherwise, execute step S250; S240. Determine whether the number of motor code matching values is less than the set value. If so, enter the position self-learning mode; otherwise, enter the normal shifting mode and rotate according to the switch required gear position; S250. Enter the fault diagnosis mode.

3. The transfer case shift control method with gear position redundant signals according to claim 2, characterized in that In step S250, the fault diagnosis mode includes the following steps: S251. Determine whether the motor has completed rotating in the direction of the 2H gear position. If so, execute step S252; otherwise, control the motor to rotate in the direction of the 2H gear position, record the motor code values and gear switch values that appear in sequence, and execute step S252; S252. Determine whether the number of matching fault code values is less than the set value. If it is less, execute step S253; otherwise, enter the fault type confirmation mode; S253. Control the motor to rotate in the direction of the 4L gear position, record the motor code values that appear in sequence, and determine whether the number of matching fault code values is less than the set value. If so, prompt for a shifting fault and prohibit shifting; otherwise, enter the fault type confirmation mode.

4. The transfer case shift control method with gear position redundant signals according to claim 3, characterized in that, In step S320, the fault type confirmation mode includes the following steps: S321. Determine whether the switch combination value is consistent with the designed value. If so, enter the function degradation gearshift mode; otherwise, prompt a position sensor failure and prohibit gear shifting.

5. The transfer case shift control method with gear position redundant signals according to claim 4, characterized in that The function degradation gearshift mode includes: Use the gear position switch signal as the gear position signal to control the transfer case to shift gears; and prompt a motor position failure.

6. The transfer case shift control method with gear position redundant signals according to claim 1, wherein In the step S400, the normal gearshift mode includes: S410. Receive the four-wheel drive switch gear position demand signal and compare it with the current gear position of the transfer case; S420. Determine whether to enter the normal gearshift mode according to the vehicle state signal.

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