Modularized multi-shaft redundant braking system and distributed calculation and distribution method for braking pressure of modularized multi-shaft redundant braking system

Abstract

The invention provides a modular multi-shaft redundant braking system and a braking pressure distributed calculation and distribution method thereof. The system comprises an air storage tank, a battery and a plurality of redundant brake units arranged on all axles of the multi-axle vehicle respectively, and each axle of the multi-axle vehicle is independently provided with one redundant brake unit. The shaft redundant brake unit comprises a redundant brake module, and a shaft left wheel brake cylinder, a shaft right wheel brake cylinder, a shaft left wheel speed sensor and a shaft right wheel speed sensor which are respectively connected with the redundant brake module; the redundant braking module is connected with the air storage tank and the battery so as to obtain a braking air source and a working power source. The communication networks of all the redundant brake modules are mutually connected and are connected with a whole vehicle network; the problems that an existing redundant braking system is high in cost and low in redundancy are solved.

Description

Technical Field

[0001] This invention belongs to the field of vehicle redundant braking technology, specifically relating to a modular multi-axle redundant braking system and its distributed calculation and allocation method for braking pressure. Background Technology

[0002] For vehicles that were not designed with redundant braking functionality from the outset, adding a redundant module can achieve redundancy at a relatively low cost. For example, the redundant braking systems in patents CN116767165A and CN202111442855.6 both add a redundant module with redundant functionality to the existing braking system (each axle has an axle module + a master controller). This approach has a simple configuration and requires minimal modification to the original braking system. However, for vehicles that require redundant braking functionality from the outset, this solution requires adding a redundant module, and each module also needs to have an integrated ECU and a dedicated controller. The central control ECU (Electronic Control Unit) increases the cost of such vehicles. The above solution, applied to multi-axle vehicles (e.g., the technical solution in patent CN118560443B), requires three ECUs for nine-axle vehicles, further increasing system costs. Furthermore, the system distributes braking pressure to each axle module via the central control unit; if the central control unit fails, the braking of each axle also fails. If redundant modules also fail, the entire system fails. In systems with high safety requirements (e.g., military vehicles, high-speed trains), the redundancy level of this system is still insufficient, and further increasing redundancy requires adding redundant modules, which in turn further increases system costs.

[0003] In view of this, the present invention proposes a modular multi-axis redundant braking system and a method for distributed calculation and allocation of braking pressure. Summary of the Invention

[0004] The purpose of this invention is to propose a modular multi-axis redundant braking system and its distributed calculation and allocation method for braking pressure, so as to solve the problems of high system cost and low redundancy.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A modular multi-axle redundant braking system includes 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. The axle redundant braking unit includes a redundant braking module, and left wheel brake cylinders, right wheel brake cylinders, 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 source and operating power. The communication networks of all redundant braking modules are interconnected and connected to the vehicle network.

[0007] The redundant braking module calculates the wheel slip ratio based on the wheel speeds of the left and right wheels of the axle collected by the left and right wheel speed sensors and the vehicle longitudinal acceleration obtained from the vehicle network; it calculates the integral value of insufficient slip ratio based on the wheel slip ratio to determine whether the axle braking pressure is sufficient; and it sends the current axle status information to the outside using the communication network in combination with the sufficiency of the axle braking pressure.

[0008] The redundant braking module performs distributed calculations of braking pressure based on braking requests received from the vehicle network and status information of other axles obtained from the communication network. It then controls the output pressure of the left and right wheel brake cylinders based on the calculated target braking pressure to achieve redundant braking.

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

[0011] 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.

[0012] The redundant braking modules corresponding to the even-numbered axles arranged sequentially along the longitudinal direction of the vehicle are connected to another set of air tanks and batteries.

[0013] A method for distributed calculation and allocation of braking pressure in a modular multi-axle redundant braking system, wherein the method is implemented using any of the aforementioned modular multi-axle redundant braking systems, specifically including the following steps:

[0014] 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 the preset threshold, the current wheel is determined to have insufficient braking force. If both wheels on the current axle are determined to have insufficient braking force, the current axle is determined to have a braking force insufficient fault. Otherwise, it is considered that there is no braking force insufficient fault.

[0015] S2. Each axle of the vehicle sends its current axle status information to the outside world through the redundant braking module via the communication network, including fault flag bits representing fault conditions and heartbeat information indicating that the microcontroller is working normally; the fault conditions include insufficient braking force.

[0016] 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.

[0017] The vehicle target acceleration is obtained based on the braking request, and fault judgment is performed on other axes except its own axis cyclically 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 axle based on the vehicle's target acceleration, the expression for the braking pressure of its own axle, and the broadcast braking force that needs to be compensated.

[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 have not failed, the braking pressure expressions for each axle of the vehicle when all axles have not failed 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 wheel's rolling radius.

[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 Figure 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 cyclically 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 axle based on the vehicle's target acceleration, the expression for the braking pressure of its own axle, and the broadcast braking force that needs to be compensated.

[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 wheel's rolling radius.

[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 system includes an air tank, a battery, and multiple redundant braking units 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 and a left-wheel brake cylinder, a right-wheel brake cylinder, a left-wheel wheel speed sensor, and a right-wheel wheel speed sensor, all 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. The communication networks of all redundant braking modules are interconnected and connected to the vehicle network. The redundant braking module calculates the wheel slip ratio based on the wheel speeds of the left and right wheels of the axle collected by the left and right wheel speed sensors and the vehicle longitudinal acceleration obtained from the vehicle network; it calculates the integral value of insufficient slip ratio based on the wheel slip ratio to determine whether the axle braking pressure is sufficient; and it sends the current axle status information to the outside using the communication network in combination with the sufficiency of the axle braking pressure. The redundant braking module performs distributed calculations of braking pressure based on braking requests received from the vehicle network and status information of other axles obtained from the communication network. It then controls the output pressure of the left and right wheel brake cylinders based on the calculated target braking pressure to achieve redundant braking.

2. The modular multi-axis redundant braking system according to claim 1, characterized in that, 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.

3. The modular multi-axis redundant braking system according to claim 1, characterized in that, 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: 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. The redundant braking modules corresponding to the even-numbered axles arranged sequentially along the longitudinal direction of the vehicle are connected to another set of air tanks and batteries.

4. A distributed calculation and allocation method for braking pressure in a modular multi-axle redundant braking system, characterized in that, The method is implemented using any of the modular multi-axis redundant braking systems described in claims 1-3, and specifically includes the following steps: 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 the preset threshold, the current wheel is determined to have insufficient braking force. If both wheels on the current axle are determined to have insufficient braking force, the current axle is determined to have a braking force insufficient fault. Otherwise, it is considered that there is no braking force insufficient fault. S2. Each axle of the vehicle sends its current axle status information to the outside world through the redundant braking module via the communication network, including fault flag bits representing fault conditions and heartbeat information indicating that the microcontroller is working normally; the fault conditions include insufficient braking force. 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. The vehicle target acceleration is obtained based on the braking request, and fault judgment is performed on other axes except its own axis cyclically based on the status information of other axes. 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. Calculate the target braking pressure of the axle based on the vehicle's target acceleration, the expression for the braking pressure of its own axle, and the broadcast braking force that needs to be compensated.

5. The modular multi-axis redundant braking system brake pressure distributed calculation and allocation method according to claim 4, characterized in that, The integral value of the insufficient slip ratio of the wheel is calculated as follows: 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: 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: 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.

6. The modular multi-axis redundant braking system brake pressure distributed calculation and allocation method according to claim 5, characterized in that, Mapping function between vehicle acceleration and minimum slip ratio Set to: Among them, the vehicle acceleration Vehicle longitudinal acceleration Differentiating yields the result.

7. The modular multi-axis redundant braking system brake pressure distributed calculation and allocation method according to claim 4, characterized in that, The pre-stored braking pressure expressions for the vehicle's own axle and adjacent axles when all axles are functioning correctly are as follows: 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 coefficient 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; Load transfer coefficient of the i-th axis and the static load of the i-th axis The specific calculation is as follows: 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. Taking the i-th axis as its own axis, then the adjacent axis i* is the (i+1)-th axis or the (i-1)-th axis. The expression for the braking pressure of its own axis when all axes have not failed is stored in advance. And the braking pressure expression for adjacent shafts ; when And when i=n, ​​adjacent axes This refers to the first axis; when And when i=1, adjacent axes It refers to the nth axis.

8. The modular multi-axis redundant braking system brake pressure distributed calculation and allocation method according to claim 7, characterized in that, The fault diagnosis of other axes (excluding the self axis) is performed cyclically based on the status information of other axes, as follows: 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. 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. 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.

9. The modular multi-axis redundant braking system brake pressure distributed calculation and allocation method according to claim 8, characterized in that, The calculation of the braking force required to compensate for the failure of the faulty axle is based on the target acceleration of the whole vehicle and the braking pressure expression of the adjacent axle. The specific calculation is as follows: 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 wheel's rolling radius.

10. The modular multi-axis redundant braking system brake pressure distributed calculation and allocation method according to claim 8, characterized in that, The target braking pressure of the vehicle's own axle is calculated based on the target acceleration of the entire vehicle, the expression for the braking pressure of its own axle, and the broadcast braking force that needs to be compensated, as follows: 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.

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