Modular multi-axis redundant brake system and its brake pressure distributed computing allocation method

Abstract

The application provides a modular multi-axle redundant braking system and a braking pressure distributed computing and distribution method thereof. The system comprises a gas storage tank, a battery and a plurality of redundant braking units respectively arranged on each axle of a multi-axle vehicle, wherein each axle of the multi-axle vehicle is provided with a redundant braking unit; the axle redundant braking unit comprises a redundant braking module, an axle left wheel braking wheel cylinder, an axle right wheel braking wheel cylinder, an axle left wheel speed sensor and an axle right wheel speed sensor connected with the redundant braking module; the redundant braking module is connected with the gas storage tank and the battery to obtain a braking gas source and a working power supply; the communication networks of all the redundant braking modules are connected with each other and the vehicle network; and the application solves the problems of high cost and low redundancy of the existing redundant braking system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vehicle redundant braking, and particularly relates to a modular multi-axle redundant braking system and a distributed calculation and distribution method of braking pressure thereof. BACKGROUND

[0002] For a vehicle without a redundant braking function at the beginning of design, adding a redundant module to the vehicle can achieve redundancy at a small cost. For example, the redundant braking systems of patents CN116767165A and CN202111442855.6 both add a redundant module with a redundant function to the original braking system (each axle has an axle module + a total control). This way is simple in configuration and has little change to the original braking system. However, for a vehicle that requires a redundant braking function at the beginning of design, this scheme needs to add a redundant module while each module needs to have an ECU built-in and a total control ECU, which makes the cost of such a vehicle higher. The above-mentioned scheme is applied to a multi-axle vehicle, for example, the technical scheme of patent CN118560443B needs 3 ECUs on a nine-axle vehicle, and the system cost is even higher. In addition, the above-mentioned system distributes the braking pressure of each axle module by the main control. Once the main control is broken, the braking of each axle is also disabled. If the redundant module is also disabled, the system is completely disabled. In a system with high safety performance (such as a military vehicle or a high-speed train), the redundancy degree of this system still cannot meet the requirements. Further increasing the redundancy degree can only be achieved by adding a redundant module, which will further increase the system cost.

[0003] In view of this, the present application provides a modular multi-axle redundant braking system and a distributed calculation and distribution method of braking pressure thereof. SUMMARY

[0004] The present application aims to provide a modular multi-axle redundant braking system and a distributed calculation and distribution method of braking pressure thereof to solve the problems of high system cost and low redundancy.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0006] The modular multi-axle redundant braking system comprises a gas tank, a battery, and a plurality of redundant braking units respectively arranged on each axle of a multi-axle vehicle. Each axle of the multi-axle vehicle is separately provided with a redundant braking unit. The axle redundant braking unit comprises a redundant braking module, and an axle left wheel brake cylinder, an axle right wheel brake cylinder, an axle left wheel speed sensor, and an axle right wheel speed sensor connected to the redundant braking module. The redundant braking module is connected to the gas tank and the battery to obtain a braking gas source and a working power source. The communication networks of all redundant braking modules are connected to each other and to the vehicle network.

[0007] The redundancy brake module calculates wheel slip ratio according to axle left wheel speed and axle right wheel speed collected by axle left wheel speed sensor and axle right wheel speed sensor, and vehicle longitudinal acceleration obtained from vehicle network; calculates integral value of insufficient slip ratio based on wheel slip ratio to determine whether axle brake pressure is sufficient; and sends current axle state information to outside by using communication network in combination with sufficient condition of axle brake pressure.

[0008] The redundancy brake module performs distributed calculation of brake pressure according to brake request received from vehicle network and state information of other axles obtained from communication network, and performs output pressure control of axle left wheel brake cylinder and axle right wheel brake cylinder according to target brake pressure obtained by calculation to realize redundancy brake.

[0009] Preferably, the number of gas tanks and batteries is configured as 1, or the number of gas tanks and batteries is configured as 2.

[0010] Preferably, when the number of gas tanks and batteries is configured as 2, the connection mode of the plurality of redundancy brake modules corresponding to the plurality of axles with the gas tanks and the batteries is as follows:

[0011] The redundancy brake module corresponding to the odd axle arranged in sequence along the longitudinal direction of the vehicle is connected with a group of gas tanks and batteries;

[0012] The redundancy brake module corresponding to the even axle arranged in sequence along the longitudinal direction of the vehicle is connected with another group of gas tanks and batteries.

[0013] The method for distributed calculation and distribution of brake pressure of the modular multi-axle redundancy brake system, the method is realized by using any of the above modular multi-axle redundancy brake systems, and specifically includes the following steps:

[0014] S1, each axle of the vehicle calculates integral value of insufficient slip ratio of each wheel on the current axle by the redundancy brake module, if the integral value of insufficient slip ratio of the wheel is greater than a preset threshold, the current wheel is determined as insufficient brake force, if both wheels on the current axle are determined as insufficient brake force, the current axle is determined as having insufficient brake force failure, otherwise it is considered that there is no insufficient brake force failure;

[0015] S2, each axle of the vehicle sends current axle state information to outside by the redundancy brake module using communication network, including fault flag bit representing fault condition and heartbeat information representing normal work of single-chip microcomputer; the fault condition includes insufficient brake force failure;

[0016] S3, each axle of the vehicle receives brake request and state information of other axles by the redundancy brake module, and pre-stores brake pressure expression of the axle and adjacent axles when all axles are not failed;

[0017] The vehicle target acceleration is obtained based on the braking request, and fault judgment is performed on other axes except its own axis in a loop based on the status information of other axes.

[0018] For the faulty axle, the braking force required to compensate for the failure of the faulty axle is calculated based on the target acceleration of the whole vehicle and the braking pressure expression of the adjacent axle, and broadcast through the communication network.

[0019] Calculate the target braking pressure of the vehicle axle based on the target acceleration of the whole vehicle, the braking pressure expression of its own axle, and the braking force that needs to be compensated as broadcast.

[0020] Preferably, the integral value of the insufficient slip ratio of the wheel is calculated as follows:

[0021]

[0022] in: Let t represent the cost function of insufficient braking pressure on wheel k at the current moment. Its physical meaning is the integral value of insufficient slip ratio, and t represents the current moment. Indicates the calculation period; The attenuation coefficient; function The calculation is as follows:

[0023]

[0024] To achieve the minimum slip ratio, through the vehicle acceleration The mapping function with minimum slip ratio is obtained, i.e. ; Let k be the slip ratio of wheel:

[0025]

[0026] in, To obtain the vehicle's longitudinal acceleration from the vehicle network; Let K be the wheel speed of wheel k, which is measured by the wheel speed sensor corresponding to wheel k.

[0027] Preferred mapping function between vehicle acceleration and minimum slip ratio Set to:

[0028]

[0029] Among them, the vehicle acceleration Vehicle longitudinal acceleration Differentiating yields the result.

[0030] Preferably, in the pre-stored braking pressure expressions for the vehicle's own axle and adjacent axles when all axles are functioning correctly, the braking pressure expressions for each axle of the vehicle when all axles are functioning correctly are as follows:

[0031]

[0032] in: This represents the braking pressure required for the i-th axis when all axes are functioning correctly. Based on the target acceleration of the whole vehicle The target acceleration of the whole vehicle is obtained by calculating the braking parameters of the i-th axis. Obtained based on braking requests received from the vehicle network; Let be the rolling radius of the wheel on the i-th axis; The ratio of braking pressure to braking torque on the i-th axis; Let be the load transfer factor for the i-th axis; It is the acceleration due to gravity; Slope; Let be the static load of the i-th axis, representing the load of the i-th axis when stationary on a horizontal road surface;

[0033] Load transfer coefficient of the i-th axis and the static load of the i-th axis The calculation is as follows:

[0034]

[0035]

[0036] in: The sprung mass of the entire vehicle; m is the height of the center of gravity; m is the mass of the vehicle. , , , respectively, are the stiffness of the i-th axis, the r-th axis, and the m-th axis; , , These represent the distances from the center of the i-th axis, the r-th axis, and the m-th axis to the center line of the 1-th axis, respectively. r and m are used to traverse each axis of the vehicle, and n is the total number of axes of the vehicle. This is the distance from the vehicle's center of gravity to the center line of the first axle.

[0037] Taking the i-th axis as its own axis, then the adjacent axes For the (i+1)th or (i-1)th axis, pre-store the expression for its own axis braking pressure when all axes have not failed. And the braking pressure expression for adjacent shafts ;

[0038] when And when i=n, ​​adjacent axes This refers to the first axis;

[0039] when And when i=1, adjacent axes It refers to the nth axis.

[0040] Preferably, the step of cyclically determining faults in axes other than the axis itself based on the status information of other axes is as follows:

[0041] When the i-th axis is itself and the adjacent axis is the (i+1)-th axis, the fault judgment is performed on the (i+1)-th axis, the (i+2)-th axis, ... the n-th axis, the 1-th axis, the 2-th axis, ... the (i-1)-th axis in sequence until a non-faulty axis is determined, then the fault judgment on the next axis after the non-faulty axis is stopped.

[0042] When the i-th axis is itself and the adjacent axis is the (i-1)-th axis, the fault judgment is performed on the (i-1)-th axis, the (i-2)-th axis, ... the 1st axis, the n-th axis, the (n-1)-th axis, the (n-2)-th axis, ... the (i+1)-th axis in sequence until a non-faulty axis is determined, then the fault judgment on the next axis after the non-faulty axis is stopped.

[0043] If a fault flag is received from another axis other than its own axis, or if a heartbeat message is received but is abnormal, or if no heartbeat message is received, the axis is judged to be faulty; otherwise, it is judged to be non-faulty.

[0044] Preferably, the calculation of the braking force required to compensate for the failure of the faulty axle, based on the target acceleration of the entire vehicle and the braking pressure expression of the adjacent axle, is specifically calculated as follows:

[0045]

[0046] in: This indicates the braking force that needs to be compensated for when the faulty axis j fails; when the adjacent axis of the i-th axis fails... When it is the (i+1)th axis, When the adjacent axes of the i-th axis When it is the (i-1)th axis, ; Indicates adjacent axes The ratio coefficient between braking pressure and braking torque; adjacent axes The rolling radius of the wheel.

[0047] Preferably, the step of calculating the target braking pressure of the axle based on the target acceleration of the whole vehicle, the braking pressure expression of its own axle, and the broadcast braking force that needs to be compensated is as follows:

[0048]

[0049]

[0050] in: The target braking pressure for the i-th axis; The braking pressure compensated for by the i-th axis; n' is the number of failed axes.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The modular multi-axis redundant braking system proposed in this invention enables each axle to accept braking requests and perform braking. When an axle fails, other axles increase their braking pressure to compensate for the insufficient braking pressure of the failed axle. This approach makes each axle redundant to the others, resulting in a high degree of system redundancy. Furthermore, the distributed computing architecture eliminates the need for a central control unit, reducing system complexity and cost. Moreover, by changing the number of axle modules, this system can be easily extended to multi-axle chassis with different numbers of axles. Attached Figure Description

[0053] Figure 1 This is a diagram of a redundant braking architecture with a single power supply and a single air source in one embodiment of the present invention;

[0054] Figure 2 This is a diagram of a redundant braking architecture with dual power supply and dual air source in one embodiment of the present invention. Detailed Implementation

[0055] The following is in conjunction with the appendix Figures 1-2 The technical solution of the present invention will be described in detail below.

[0056] This invention proposes a modular multi-axle redundant braking system, including an air tank, a battery, and multiple redundant braking units respectively configured on each axle of a multi-axle vehicle. Each axle of the multi-axle vehicle is equipped with a separate redundant braking unit. Each axle redundant braking unit includes a redundant braking module bi (sequentially numbering the axles along the longitudinal direction of the vehicle as 1, 2, 3, ..., i, ..., n, where n is the total number of axles), and brake wheel cylinders a (including left wheel brake cylinder 21 and right wheel brake cylinder 22) and wheel speed sensors c (including left wheel speed sensors and right wheel speed sensors) connected to the redundant braking module. The redundant braking module is connected to the air tank and the battery to obtain brake air and power sources, respectively. The communication networks of all redundant braking modules are interconnected and connected to the vehicle network to obtain information from the vehicle network.

[0057] The redundant braking module calculates the wheel slip ratio based on the wheel speeds of the left and right wheels collected by the left and right wheel speed sensors and the vehicle longitudinal acceleration obtained from the vehicle network. It then calculates the integral value of any insufficient slip ratio to determine if the axle braking pressure is sufficient. Combining this with the axle braking pressure status, it sends the current axle's status information to the outside via the communication network. Other axles can use this signal to determine if the axle has failed. If an axle failure is detected, the module determines whether it should take over some of the axle's functions, thereby increasing the braking pressure.

[0058] Each axle independently receives braking requests from the vehicle network and converts them into target braking pressure. Specifically, the redundant braking module performs distributed calculation of braking pressure based on the braking requests received from the vehicle network and the status information of other axles obtained from the communication network, and controls the output pressure of the left wheel brake cylinder and the right wheel brake cylinder of the axle according to the calculated target braking pressure to achieve redundant braking.

[0059] refer to Figure 1 and Figure 2 The number of gas tanks and batteries is configured as 1 each, or the number of gas tanks and batteries is configured as 2 each.

[0060] When both the air tank and the battery are configured to be two, the connection methods between the multiple redundant braking modules corresponding to the multi-axle system and the air tank and battery are as follows:

[0061] The redundant braking modules corresponding to the odd-numbered axles of the vehicle, which are arranged sequentially along the longitudinal direction of the vehicle, are connected to a set of air tanks and batteries.

[0062] The redundant braking modules corresponding to the even-numbered axles of the vehicle, which are arranged sequentially along the longitudinal direction of the vehicle, are connected to another set of air tanks and batteries.

[0063] With the above setup, only one battery and air tank need to be added, and the rest of the circuits, air circuits, and software do not need to be adjusted. This can meet the high redundancy requirements of military or rail applications at a very low cost. When one of the batteries, air tanks, or the circuits or air circuits connected to them fails, only half of the axles, which are evenly spaced, will fail. In this way, the braking force is still distributed in the longitudinal direction of the entire vehicle (from front to back). This will prevent the failure from causing only the front or rear to brake, thus avoiding unsafe phenomena such as understeer, fishtailing, or skidding.

[0064] This invention also proposes a distributed calculation and allocation method for braking pressure in a modular multi-axle redundant braking system. The method is implemented using any of the aforementioned modular multi-axle redundant braking systems and specifically includes the following steps:

[0065] S1. The redundant braking module calculates the integral value of the insufficient slip ratio of each wheel on the current axle. If the integral value of the insufficient slip ratio of the wheel is greater than a preset threshold... ( When the value is 0.2, it is considered that the insufficient slip ratio has lasted for a period of time, and the current wheel is judged to have insufficient braking force. In order to reduce the probability of false judgment, if both wheels on the current axle are judged to have insufficient braking force, the current axle is judged to have insufficient braking force fault; otherwise, it is considered that there is no insufficient braking force fault.

[0066] Determining whether each axle is functioning properly is a prerequisite for achieving redundant braking. Each axle needs to determine whether it and the other axles are functioning properly. Since the greater the braking pressure, the greater the braking force of the wheel, and the greater its corresponding slip ratio, this means that the greater the deceleration of the whole vehicle, the greater the braking pressure provided by each wheel, and the greater its corresponding slip ratio should also be. Therefore, a wheel braking pressure fault judgment method is set up based on this rule.

[0067] S2. Each axle of the vehicle sends its current status information to the outside world through the redundant braking module via the communication network. This includes a fault flag representing the fault condition (the sending logic can be set to different values ​​corresponding to different faults, for example, 0 when there is no fault and not 0 when there is a fault), and heartbeat information indicating that the microcontroller is working normally (for example, it can cycle through 0, 1, 2, 3...253, 254, 255, 0, 1... every 20ms). The fault conditions include insufficient braking force or other internal faults.

[0068] S3. Each axle of the vehicle receives braking requests and status information from other axles through a redundant braking module, and pre-stores the braking pressure expressions for its own axle and adjacent axles when all axles have not failed.

[0069] The vehicle target acceleration is obtained based on the braking request, and fault judgment is performed on other axes except its own axis in a loop based on the status information of other axes.

[0070] For the faulty axle, the braking force required to compensate for the failure of the faulty axle is calculated based on the target acceleration of the whole vehicle and the braking pressure expression of the adjacent axle, and broadcast through the communication network.

[0071] Calculate the target braking pressure of the vehicle axle based on the target acceleration of the whole vehicle, the braking pressure expression of its own axle, and the braking force that needs to be compensated as broadcast.

[0072] In this embodiment, the integral value of the insufficient slip ratio of the wheel is calculated as follows:

[0073]

[0074] in: Let t represent the cost function of insufficient braking pressure on wheel k at the current moment. Its physical meaning is the integral value of insufficient slip ratio, and t represents the current moment. Indicates the calculation period (which can be set to 10ms); The attenuation coefficient (can be taken as 0.98); function The calculation is as follows:

[0075]

[0076] To achieve the minimum slip ratio, through the vehicle acceleration The mapping function with minimum slip ratio is obtained, i.e. ; Let k be the slip ratio of wheel:

[0077]

[0078] in, To obtain the vehicle's longitudinal acceleration from the vehicle network (there are already relevant technologies for calculating the vehicle's longitudinal acceleration, which will not be elaborated here); Let k be the wheel speed, which is measured by the wheel speed sensor corresponding to wheel k. The subscript k indicates the kth wheel. For example, the left wheel of the first axle is 1 and the right wheel is 2, the left wheel of the second axle is 3 and the right wheel is 4, and so on.

[0079] In this embodiment, the mapping function between the vehicle acceleration and the minimum slip ratio is obtained through experiments. One possible setting is:

[0080]

[0081] Among them, the vehicle acceleration Vehicle longitudinal acceleration Differentiation yields that during braking... .

[0082] In this embodiment, when all axles are not in failure, the braking pressure distribution of each axle of the vehicle is calculated based on the axle load of the whole vehicle and the braking pressure is distributed proportionally according to the axle load so that all wheels lock up synchronously. This can prevent the vehicle from experiencing unsafe phenomena such as understeer, fishtailing, or skidding.

[0083] The actual load on each axis is: In the formula The actual load on the i-th axis. For equivalent deceleration, , It is the acceleration due to gravity. The slope (downhill is positive) is here. Let i be the load transfer factor for the i-th axis:

[0084]

[0085] in: The sprung mass of the entire vehicle; The height of the center of mass; , , , respectively, are the stiffness of the i-th axis, the r-th axis, and the m-th axis; , , These represent the distances from the center of the i-th axis, the r-th axis, and the m-th axis to the center line of the 1-th axis, respectively. r and m are used to traverse each axis of the vehicle.

[0086] Let be the static load of the i-th axis, representing the load of the i-th axis when stationary on a horizontal road surface;

[0087]

[0088] Where: m is the total vehicle mass; This is the distance from the vehicle's center of gravity to the center line of the first axle.

[0089] The actual load on the i-th axis The actual acceleration of the whole vehicle in the expression (Obtained by differentiating the vehicle's longitudinal acceleration) Replace with the target acceleration of the entire vehicle. (Acceleration command) Obtain the target load on the i-th axis. The braking pressure expressions for each axle of the vehicle when all axles are functioning correctly are as follows:

[0090]

[0091] in: Let be the rolling radius of the wheel on the i-th axis. The ratio of braking pressure to braking torque on the i-th axis is given by the above parameters, which are all structural parameters of the vehicle and can be obtained before leaving the factory. This represents the braking pressure required for the i-th axis when all axes are functioning correctly. Based on the target acceleration of the whole vehicle The target acceleration of the whole vehicle is obtained by calculating the braking parameters of the i-th axis. Based on the braking request received from the vehicle network ( <0);

[0092] In the pre-stored braking pressure expressions for the self-axis and adjacent axes when all axes have not failed, taking the i-th axis as the self-axis, then the adjacent axes... For the (i+1)th or (i-1)th axis, pre-store the expression for its own axis braking pressure when all axes have not failed. And the braking pressure expression for adjacent shafts ;

[0093] when And when i=n, ​​adjacent axes This refers to the first axis;

[0094] when And when i=1, adjacent axes It refers to the nth axis.

[0095] In this embodiment, the fault diagnosis of axes other than the self-axis is performed cyclically based on the status information of other axes, as follows:

[0096] Taking the i-th axis as its own axis and the adjacent axis as the (i+1)-th axis, fault diagnosis is performed sequentially on the (i+1)-th axis, the (i+2)-th axis, ..., the n-th axis, the 1st axis, the 2nd axis, ..., the (i-1)-th axis, until a non-faulty axis is identified. At this point, fault diagnosis for the next axis after the non-faulty axis stops. Specifically: the i-th axis first checks if the next axis after it (i+1) is faulty. If it is faulty, the i-th axis takes over the calculation tasks of the (i+1)-th axis and simultaneously publishes the braking force compensation required due to the failure of the (i+1)-th axis on the vehicle network. In the formula, j is taken as i+1; at the same time, since the (i+1)th axis fails, if the (i+2)th axis fails, there will be no axis responsible for broadcasting the need for the (i+2)th axis. When the (i+1)th axis fails, the (i)th axis simultaneously checks whether the (i+2)th axis has failed. If it has failed, the braking force that the (i+2)th axis needs to compensate for is calculated according to j=i+1. The braking force parameters of the i-th axle are broadcast on the vehicle network (since only the braking force parameters of the i+1-th axle are stored for the i-th axle, but the characteristics of adjacent axles are generally not very different, the braking force that the i+1-th axle needs to compensate for can be approximated), and the calculation continues for i+3, i+4, ... until an axle without failure is identified; the braking force that the faulty axle j needs to compensate for is... The specific calculations are as follows:

[0097]

[0098] in: ; Indicates adjacent axes The ratio coefficient between braking pressure and braking torque; adjacent axes The rolling radius of the wheel.

[0099] Similarly, taking the i-th axis as its own axis and the adjacent axis as the (i-1)-th axis, fault detection is performed sequentially on the (i-1)-th axis, the (i-2)-th axis, ..., the 1st axis, the nth axis, the (n-1)-th axis, the (n-2)-th axis, ..., the (i+1)-th axis, until a non-faulty axis is identified. Then, fault detection for the next axis after the non-faulty axis is stopped. The braking force that needs to be compensated for when the faulty axis j fails is... The specific calculations are as follows:

[0100]

[0101] in: ; Indicates adjacent axes The ratio coefficient between braking pressure and braking torque; adjacent axes The rolling radius of the wheel;

[0102] If a fault flag is received from another axis other than its own axis, or if a heartbeat message is received but is abnormal, or if no heartbeat message is received, the axis is judged to be faulty; otherwise, it is judged to be non-faulty.

[0103] In this embodiment, the calculation of the target braking pressure of the axle based on the vehicle's target acceleration, the braking pressure expression of its own axle, and the broadcasted braking force requiring compensation is as follows:

[0104]

[0105]

[0106] in: The target braking pressure for the i-th axis; The braking pressure compensated for by the i-th axis; n' is the number of failed axes.

[0107] The above method ensures that the program for each axle is consistent. Only different pre-approval parameters (related to vehicle parameters) and an identifier for that axle (used for communication to indicate it is the i-th axle) need to be input. The resulting vehicle braking system will automatically respond to acceleration requests on the vehicle communication network. When an axle malfunctions, it will automatically reassemble to achieve braking redundancy. Furthermore, since each axle only calculates its own braking pressure and determines the fault status of its adjacent axles, the overall computational load is relatively small.

[0108] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A modular multi-axis redundant braking system, characterized in that, The application relates to a multi-axle vehicle redundancy braking system comprising a gas tank, a battery and a plurality of redundancy braking units respectively arranged on each axle of the multi-axle vehicle, wherein each axle of the multi-axle vehicle is provided with one redundancy braking unit; the axle redundancy braking unit comprises a redundancy braking module, an axle left wheel brake cylinder, an axle right wheel brake cylinder, an axle left wheel speed sensor and an axle right wheel speed sensor connected with the redundancy braking module; the redundancy braking module is connected with the gas tank and the battery to obtain a braking gas source and a working power source; the communication networks of all the redundancy braking modules are connected with each other and with a vehicle network; The redundancy braking module calculates a wheel slip ratio according to axle left wheel speed and axle right wheel speed collected by the axle left wheel speed sensor and the axle right wheel speed sensor and vehicle longitudinal acceleration obtained from the vehicle network; an integral value of insufficient wheel slip ratio is calculated based on the wheel slip ratio to determine whether the axle braking pressure is sufficient; and the current axle state information is sent to the outside through the communication network in combination with the sufficient condition of the axle braking pressure; The redundancy braking module performs distributed calculation of the braking pressure according to a braking request received from the vehicle network and state information of other axles obtained from the communication network, and performs output pressure control on the axle left wheel brake cylinder and the axle right wheel brake cylinder according to the target braking pressure obtained through the calculation to realize redundancy braking; The distributed calculation of the braking pressure specifically comprises the following steps: S1, each axle of the vehicle calculates an integral value of insufficient wheel slip ratio of each wheel on the current axle through the redundancy braking module, and if the integral value of insufficient wheel slip ratio of the wheel is greater than a preset threshold value, the current wheel is determined as having insufficient braking force; if both wheels on the current axle are determined as having insufficient braking force, the current axle is determined as having a braking force insufficient fault, otherwise, it is considered that there is no braking force insufficient fault; S2, each axle of the vehicle sends the current axle state information to the outside through the redundancy braking module and the communication network, including a fault flag bit representing a fault condition and heartbeat information representing normal operation of a single-chip microcomputer; the fault condition includes a braking force insufficient fault; S3, each axle of the vehicle receives a braking request and state information of other axles through the redundancy braking module, and pre-stores braking pressure expression of the self axle and adjacent axles when all the axles are not failed; The vehicle target acceleration is obtained according to the braking request, and fault judgment is performed on other axles except the self axle according to the state information of the other axles; For the fault axle, the braking force required to be compensated due to the failure of the fault axle is calculated according to the vehicle target acceleration and the braking pressure expression of the adjacent axles, and is broadcast through the communication network; The target braking pressure of the self axle is calculated according to the vehicle target acceleration, the braking pressure expression of the self axle and the required compensation braking force broadcasted; The integral value of insufficient wheel slip ratio of the wheel is calculated as follows: wherein: is the braking pressure deficit cost function for the current time instant for the wheel k, whose physical meaning is the integral value of the slip rate deficit, t denotes the current time instant; denotes the calculation period; is the decay coefficient; the function is calculated as follows: is the minimum slip ratio, obtained by the vehicle acceleration and the mapping function of the minimum slip ratio, i.e. ; is the slip ratio of the wheel k: wherein, is the vehicle longitudinal acceleration obtained from the vehicle network; is the wheel speed of wheel k measured by the wheel speed sensor corresponding to wheel k.

2. The modular multi-axis redundant braking system of claim 1, wherein, The number of the gas tank and the battery is configured as one or the number of the gas tank and the battery is configured as two.

3. The modular multi-axis redundant braking system of claim 1, wherein, When the number of the gas tank and the battery is configured as two, the connection mode of the plurality of redundancy braking modules corresponding to the multi-axles with the gas tank and the battery is as follows: The redundancy braking modules corresponding to odd axles arranged in sequence along the longitudinal direction of the vehicle are connected with one group of gas tank and battery; The redundancy brake module corresponding to the even axle arranged in sequence along the longitudinal direction of the vehicle is connected with another group of air tanks and batteries.

4. The modular multi-axis redundant braking system of claim 1, wherein, Vehicle acceleration and minimum slip ratio mapping function is set to: Wherein, the acceleration of the whole vehicle The vehicle longitudinal acceleration is derived.

5. The modular multi-axis redundant braking system of claim 1, wherein, The brake pressure expression of each axle of the vehicle when all the axles are not failed is as follows: wherein: represents the required braking pressure of the ith axle when all the axles are not failed, is calculated according to the target vehicle acceleration and the braking parameters of the ith axle, the target vehicle acceleration is obtained according to the braking request received from the vehicle network; is the rolling radius of the ith axle wheel; is the braking pressure to braking torque proportionality coefficient of the ith axle; is the load transfer coefficient of the ith axle; is the gravitational acceleration; is the slope; is the static load of the ith axle, representing the load of the ith axle when stationary on a horizontal road surface; Load transfer coefficient of the ith axis and the static load of the ith axis The calculation is as follows: wherein: is the sprung mass of the vehicle; is the height of the center of mass; m is the mass of the vehicle; , , is the stiffness of the ith, rth, mth axle, respectively; , , denotes the distance of the ith, rth, mth axle center to the 1st axle centerline, r and m are used to iterate through each of the axles of the vehicle, and n is the total number of axles of the vehicle; is the distance of the center of mass of the vehicle to the 1st axle centerline; With the i-th axis as the self-axis, the adjacent axis i* is the (i+1)-th axis or the (i-1)-th axis, and the self-axis brake pressure expression when all axes are not failed is pre-stored and the brake pressure expression of the adjacent axis ; When and i = n, the adjacent axis refers to the 1st axis; When and i = 1, the adjacent axis refers to the nth axis.

6. The modular multi-axis redundant braking system of claim 5, wherein, The fault judgment of the other axles except the self axle is performed according to the state information of the other axles, and the fault judgment is performed as follows: When the i-th axle is the self axle and the adjacent axle is the i+1-th axle, the fault judgment is performed on the i+1-th axle, the i+2-th axle,..., the n-th axle, the 1-th axle, the 2-th axle,..., the i-1-th axle in sequence until the non-fault axle is judged, and then the fault judgment of the next axle of the non-fault axle is stopped. When the i-th axle is the self axle and the adjacent axle is the i-1-th axle, the fault judgment is performed on the i-1-th axle, the i-2-th axle,..., the 1-th axle, the n-th axle, the n-1-th axle, the n-2-th axle,..., the i+1-th axle in sequence until the non-fault axle is judged, and then the fault judgment of the next axle of the non-fault axle is stopped. If the fault flag bit of the other axle except the self axle is received, or the heartbeat information is received but the heartbeat information is abnormal, or the heartbeat information is not received, the axle is judged as the fault axle, otherwise, the axle is judged as the non-fault axle.

7. The modular multi-axis redundant braking system of claim 6, wherein, The brake force needed to be compensated due to the failure of the fault axle is calculated according to the target acceleration of the vehicle and the brake pressure expression of the adjacent axle, and the calculation is as follows: wherein: represents the braking force that needs to be compensated for the failure of the jth axis; when the adjacent axis of the ith axis is the (i+1)th axis, ; when the adjacent axis of the ith axis is the (i-1)th axis, ; represents the braking pressure of the adjacent axis to the braking torque proportionality coefficient; is the wheel rolling radius of the adjacent axis .

8. The modular multi-axis redundant braking system of claim 6, wherein, The target brake pressure of the self axle is calculated according to the target acceleration of the vehicle, the brake pressure expression of the self axle and the broadcasted brake force needed to be compensated, and the calculation is as follows: wherein: target brake pressure for the i-th axis; brake pressure compensated for the i-th axis; n' is the number of failed axes.

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