A four-wheel synchronization method and system based on EMB

Abstract

The application relates to a four-wheel synchronous method and system based on EMB and relates to the technical field of vehicle braking. The method is applied to EMB, and the method comprises the following steps: acquiring the response time length of each EMB to a target clamping force request sent by a main controller; for each EMB, if the response time length of the EMB is greater than a preset response time length threshold, the EMB is determined as a response lag EMB; the EMB with the shortest response time length is determined as a standard response EMB; the first clamping force of the standard response EMB, the current motor speed and the second clamping force of the response lag EMB are respectively acquired; the clamping force adjustment amount of the response lag EMB is determined; the target motor speed of the response lag EMB is determined according to the first clamping force of the standard response EMB, the current motor speed, the second clamping force of the response lag EMB and a preset speed proportional adjustment coefficient; and the response lag EMB operates according to the clamping force adjustment amount and the target motor speed. The application can improve the consistency of four-wheel braking response.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle braking, in particular to a four-wheel synchronization method and system based on EMB. BACKGROUND

[0002] At present, in the automobile braking system, the electromechanical brake (EMB) is widely used in various vehicles due to its fast response speed, high control precision, high energy utilization efficiency and other advantages. However, in actual application, when the EMB system responds to the braking request issued by the response domain controller (i.e. upper controller), the response of the four-wheel EMB is often difficult to achieve complete synchronization, resulting in the possibility of vehicle lateral swing during braking, especially in the case of emergency braking or high-speed driving, the driving safety of the vehicle is threatened.

[0003] Therefore, how to realize the synchronous response of the four-wheel EMB and improve the braking stability and safety of the vehicle has become a technical problem to be solved. SUMMARY

[0004] Therefore, it is necessary to provide a four-wheel synchronization method and system based on EMB in view of the above technical problems.

[0005] In a first aspect, a four-wheel synchronization method based on EMB is provided, the method is applied to EMB, and the method comprises:

[0006] Obtaining the response time of each EMB to the target clamping force request sent by the master controller;

[0007] For each EMB, if the response time of the EMB is greater than a preset response time threshold, the EMB is determined as a response lag EMB;

[0008] The EMB with the shortest response time is determined as a standard response EMB;

[0009] Respectively obtaining the first clamping force, the current motor speed of the standard response EMB and the second clamping force of the response lag EMB;

[0010] According to the first clamping force of the standard response EMB and the second clamping force of the response lag EMB, the clamping force adjustment amount of the response lag EMB is determined;

[0011] According to the first clamping force of the standard response EMB, the current motor speed, the second clamping force of the response lag EMB and a preset speed proportional adjustment coefficient, the target motor speed of the response lag EMB is determined;

[0012] The response-lag EMB operates according to the clamping force adjustment amount and the target motor speed.

[0013] As an optional implementation, the method further comprises:

[0014] acquiring a first time point at which the master controller sends a target clamping force request and a second time point at which each EMB reaches the target clamping force;

[0015] for each EMB, determining a response time of the EMB to the target clamping force request sent by the master controller as a difference between the second time point and the second time point at which the EMB reaches the target clamping force.

[0016] As an optional implementation, the preset response time threshold is 50 ms.

[0017] As an optional implementation, the method further comprises:

[0018] for each EMB, if the response time of the EMB is less than or equal to the response time threshold, determining that the EMB is a response-normal EMB.

[0019] As an optional implementation, the formula for determining the clamping force adjustment amount of the response-lag EMB according to the first clamping force of the standard response EMB and the second clamping force of the response-lag EMB is:

[0020] ΔF = F1 - F2;

[0021] wherein ΔF is the clamping force adjustment amount of the response-lag EMB, F1 is the first clamping force of the standard response EMB, and F2 is the second clamping force of the response-lag EMB.

[0022] As an optional implementation, the formula for determining the target motor speed of the response-lag EMB according to the first clamping force of the standard response EMB, the current motor speed, the second clamping force of the response-lag EMB, and a preset speed proportional adjustment coefficient is:

[0023] V1 = V0 + K (F1 - F2);

[0024] wherein V1 is the target motor speed, V0 is the current motor speed of the standard response EMB, F1 is the first clamping force of the standard response EMB, F2 is the second clamping force of the response-lag EMB, and K is the preset speed proportional adjustment coefficient.

[0025] As an optional implementation, the method further comprises:

[0026] acquiring a clamping force change rate of the response-lag EMB;

[0027] dynamically reducing a motor speed of the response-lag EMB when the clamping force change rate is greater than a preset rate change safety threshold.

[0028] As an optional implementation, the method further comprises:

[0029] The EMB control of the front wheel group and the rear wheel group is independent of each other.

[0030] In a second aspect, an EMB-based four-wheel synchronization system is provided, which comprises a main controller and an EMB as described in any of the first aspect.

[0031] The application provides an EMB-based four-wheel synchronization method and system. The technical solution provided by the embodiments of the application brings at least the following beneficial effects. The method is applied to an EMB, and the method comprises: acquiring a response time of each EMB to a target clamping force request sent by a main controller; for each EMB, if the response time of the EMB is greater than a preset response time threshold, the EMB is determined to be a response-lag EMB; an EMB with the shortest response time is determined to be a standard response EMB; a first clamping force of the standard response EMB, a current motor speed of the standard response EMB, and a second clamping force of the response-lag EMB are acquired respectively; a clamping force adjustment amount of the response-lag EMB is determined according to the first clamping force of the standard response EMB and the second clamping force of the response-lag EMB; a target motor speed of the response-lag EMB is determined according to the first clamping force of the standard response EMB, the current motor speed, the second clamping force of the response-lag EMB, and a preset speed proportion adjustment coefficient; and the response-lag EMB operates according to the clamping force adjustment amount and the target motor speed. By acquiring the response time of each EMB and determining the response-lag EMB, the motor speed and the clamping force output of the lag EMB are adjusted based on the standard response EMB, which can significantly improve the consistency of four-wheel response and effectively solve the problems of poor braking stability and loss of control in extreme conditions caused by different responses in the prior art.

[0032] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the application. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0034] Figure 1 A structural schematic diagram of an EMB-based four-wheel synchronization system provided for an embodiment of the present application is shown in the figure;

[0035] Figure 2 A flowchart of an EMB-based four-wheel synchronization method provided for an embodiment of the present application is shown in the figure;

[0036] Figure 3 A flowchart of an EMB response duration calculation method provided for an embodiment of the present application is shown in the figure;

[0037] Figure 4 A flowchart of an EMB adjustment process monitoring method provided for an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0039] An EMB-based four-wheel synchronization method provided by an embodiment of the present application can be applied to an EMB-based four-wheel synchronization system. As shown in the figure, Figure 1 The system includes a main controller 110 and a plurality of EMBs 120. The main controller 110 is connected to all EMBs 120 through a vehicle communication bus (such as a CAN bus, a FlexRay bus or an Ethernet), for sending control instructions and receiving running state data. Each EMB 120 is independently connected to the communication bus, shares data and accepts instructions through the bus, and constitutes a distributed brake control architecture. The main controller 110 can also calculate the target clamping force request of each wheel according to the driver's braking demand or the intervention signal of the vehicle stability control system, and send it to the corresponding EMB 120. A plurality of EMBs 120 integrate a synchronization monitoring program. Each EMB 120 can collect its own running state parameters in real time, including actual clamping force, relative position, motor speed, current and response duration, etc. The collected parameters are uploaded to the main controller 110 through the communication bus, and broadcasted to other EMBs 120. The state data of other EMBs is read through the communication bus, and the clamping force difference and motor speed difference between itself and the standard response EMB are calculated. According to the adjustment instruction issued by the main controller 110, the motor speed and clamping force output of itself are adjusted to catch up with the standard response EMB. According to the target clamping force request sent by the main controller 110, the motor generates a corresponding braking torque, and is adjusted in real time to realize fast response. The motor current and clamping force change rate are monitored. If it exceeds the safety threshold, the protection mechanism is triggered, and the motor speed is dynamically reduced and the abnormal state is reported.

[0040] A four-wheel synchronization method based on EMBs provided by the embodiment of the application will be described in detail below in combination with specific embodiments. Figure 2 A flowchart of the four-wheel synchronization method based on EMBs provided by the embodiment of the application is shown in FIG. 2. Figure 2 The method is applied to EMBs, and the specific steps are as follows:

[0041] In step 201, the response time of each EMB to the target clamping force request sent by the master controller is obtained.

[0042] In implementation, the response time is the time interval for each EMB to reach the target clamping force after the master controller sends the target clamping force request. By comparing the response times, it can be determined which EMBs have normal or delayed responses. For example, the master controller sends a target clamping force request and records the time stamp of the request sending. Each EMB adjusts the clamping force according to the request, and records the time stamp when the clamping force reaches the target value. Then, the time interval between the time stamps is determined to determine the response time.

[0043] As an optional implementation, Figure 3 A flowchart of the calculation method of the EMB response time provided by the embodiment of the application is shown in FIG. 3. Figure 3 The specific steps of obtaining the response time of each EMB to the target clamping force request sent by the master controller in step 201 are as follows:

[0044] In step 301, the first time when the master controller sends a target clamping force request and the second time when each EMB reaches the target clamping force are obtained.

[0045] In implementation, the master controller sends a target clamping force request instruction to each EMB and records the time when the instruction is sent, which is recorded as the first time (T1). Each EMB starts to perform a clamping action after receiving the instruction and monitors the clamping force output in real time. When the actual clamping force of a certain EMB reaches the target clamping force requested by the master controller, the time is recorded, which is recorded as the second time (T2).

[0046] In step 302, for each EMB, the difference between the second time and the second time when the EMB reaches the target clamping force is determined as the response time of the EMB to the target clamping force request sent by the master controller.

[0047] In implementation, each EMB can determine the time used by each EMB to actually reach the target clamping force from receiving the target clamping force request of the master controller. The response time reflects the execution efficiency of the EMB to the instruction of the master controller.

[0048] Step 202, for each EMB, if the response duration of the EMB is greater than the preset response duration threshold, it is determined that the EMB is a response lag EMB.

[0049] In implementation, by comparing the response duration of each EMB with the preset response duration threshold (for example, 50ms), the response lag EMB is determined, so that the subsequent step takes synchronization compensation measures. For example: the preset response duration threshold is 50ms, the response duration of EMB1 is 40ms, the response duration of EMB2 is 60ms, and EMB2 is determined to be a response lag EMB.

[0050] As an optional implementation, the preset response duration threshold is 50ms.

[0051] As an optional implementation, for each EMB, if the response duration of the EMB is less than or equal to the response duration threshold, it is determined that the EMB is a response normal EMB.

[0052] Step 203, the EMB with the shortest response duration is determined as the standard response EMB.

[0053] In implementation, the EMB with the shortest response duration is selected as the reference, and its state parameters are used to calculate the compensation parameters of other response lag EMBS. For example: the response durations of four EMBS are respectively: EMB1 40ms, EMB2 60ms, EMB3 45ms, and EMB4 50ms, then the EMB with the shortest response duration is EMB1, and other EMBS determine EMB1 as the standard response EMB.

[0054] Step 204, the first clamping force of the standard response EMB, the current motor speed and the second clamping force of the response lag EMB are respectively acquired.

[0055] In implementation, each EMB can acquire the actual clamping force (first clamping force) and the current motor speed of the standard response EMB through the communication bus, and the lag EMB acquires its own actual clamping force (second clamping force), which provides basic data for subsequent synchronization adjustment. For example: the first clamping force of the standard response EMB (EMB1) is 950N, and the current motor speed is 1500rpm. The second clamping force of the response lag EMB (EMB2) is 900N.

[0056] Step 205, according to the first clamping force of the standard response EMB and the second clamping force of the response lag EMB, the clamping force adjustment amount of the response lag EMB is determined.

[0057] In implementation, the response lag EMB can calculate the clamping force adjustment amount, which is used to quickly approach the clamping force of the standard response EMB.

[0058] As an optional implementation, the formula for determining the clamping force adjustment amount of the response-lagging EMB according to the first clamping force of the standard response EMB and the second clamping force of the response-lagging EMB in step 205 is as follows:

[0059] ΔF = F1 - F2;

[0060] wherein, ΔF is the clamping force adjustment amount of the response-lagging EMB, F1 is the first clamping force of the standard response EMB, and F2 is the second clamping force of the response-lagging EMB.

[0061] In implementation, the first clamping force (F1) of the standard response EMB is the clamping force applied by the EMB that responds the fastest under the current conditions, which can be used as the target clamping force reference of the entire system. The second clamping force (F2) of the response-lagging EMB is the actual clamping force value applied by the response-lagging EMB. By calculating ΔF = F1 - F2, the clamping force difference between the response-lagging EMB and the standard response EMB can be obtained, that is, the amount of clamping force that the response-lagging EMB needs to increase or decrease to achieve the synchronization target. For example, the clamping force of the standard response EMB is F1 = 950N, and the clamping force of the response-lagging EMB is F2 = 920N; according to the formula: ΔF = F1 - F2 = 950N - 920N = 30N. The response-lagging EMB needs to adjust its motor output or control parameters to increase its clamping force by 30N, so that its clamping force is synchronized with that of the standard response EMB.

[0062] In step 206, the target motor speed of the response-lagging EMB is determined according to the first clamping force of the standard response EMB, the current motor speed, the second clamping force of the response-lagging EMB, and the preset speed proportional adjustment coefficient.

[0063] In implementation, the response-lagging EMB can calculate the target motor speed through the current motor speed of the standard response EMB and the clamping force difference, to ensure that the adjustment speed of the response-lagging EMB meets the synchronization requirement.

[0064] As an optional implementation, the formula for determining the target motor speed of the response-lagging EMB according to the first clamping force of the standard response EMB, the current motor speed, the second clamping force of the response-lagging EMB, and the preset speed proportional adjustment coefficient in step 206 is as follows:

[0065] V1 = V0 + K (F1 - F2);

[0066] wherein, V1 is the target motor speed, V0 is the current motor speed of the standard response EMB, F1 is the first clamping force of the standard response EMB, F2 is the second clamping force of the response-lagging EMB, and K is the preset speed proportional adjustment coefficient.

[0067] In implementation, V1 is the target motor speed of the response-lag EMB, representing the adjusted motor running speed to achieve the purpose of synchronous clamping force. V0 is the current motor speed of the standard response EMB, serving as a reference value, reflecting the motor running state of the response-fastest EMB. F1 and F2 are the first clamping force of the standard response EMB and the second clamping force of the response-lag EMB, respectively, reflecting the difference between the two in clamping force. K is a preset speed ratio adjustment coefficient, used to balance the relationship between the clamping force and the motor speed, avoiding excessive or insufficient adjustment. When the clamping force (F2) of the response-lag EMB is less than the clamping force (F1) of the standard response EMB, the motor speed needs to be increased, and the target speed V1 > V0. The greater the clamping force difference (F1-F2), the higher the adjustment range of the motor speed, ensuring the fast response of synchronous action. The speed ratio adjustment coefficient K can control the sensitivity of speed adjustment, which needs to be preset according to the specific braking requirements of the vehicle to ensure that the adjusted clamping force gradually approaches the target value without causing overshoot or oscillation. For example: the current motor speed V0 of the standard response EMB is 1500 rpm, the clamping force F1 of the standard response EMB is 950 N, the clamping force F2 of the response-lag EMB is 900 N, and the speed ratio adjustment coefficient K is 5 rpm / N. According to the formula, the target motor speed of the response-lag EMB can be calculated as 1750 rpm, which is 250 rpm higher than the current motor speed of the standard response EMB, aiming to reduce the clamping force difference (ΔF).

[0068] Step 207, the response-lag EMB operates according to the clamping force adjustment amount and the target motor speed.

[0069] In implementation, the response-lag EMB performs synchronous adjustment, so that its clamping force and click speed gradually approach the standard response EMB, and finally realizes four-wheel synchronous response. For example: the response-lag EMB (EMB2) adjusts the motor speed to 2000 rpm, and increases the clamping force by 40 N, so that it reaches the target clamping force 950 N required by the main controller.

[0070] As an optional implementation, Figure 4 The flow chart of the monitoring method of the EMB adjustment process provided by the embodiment of the application is shown in Figure 4 As shown in the figure, the specific steps are as follows:

[0071] Step 401, the clamping force change rate of the response-lag EMB is obtained.

[0072] In implementation, the clamping force change rate refers to the change amount of the clamping force per unit time. If the clamping force change rate is too fast, there is a risk of overshoot, which may cause vibration or instability of the brake system, and even affect the braking effect of the whole vehicle. By monitoring the clamping force change rate in real time, the motor speed of the response-lag EMB can be intervened in time to avoid safety hazards.

[0073] Step 402, when the clamping force change rate is greater than the preset rate change safety threshold, the motor speed of the response lag EMB is dynamically reduced.

[0074] In implementation, the technician can preset the safety threshold of the clamping force change rate. If the response lag EMB detects that the clamping force change rate is greater than the preset rate change safety threshold, it means that the clamping force adjustment is too fast, and the adjustment process can be slowed down by reducing the motor speed. For example, set a dynamic adjustment coefficient negatively related to the clamping force change rate.

[0075] As an optional implementation, the EMB control of the front wheel group and the rear wheel group is independent of each other.

[0076] In implementation, the EMB control of the front wheel group and the rear wheel group is independent of each other, which ensures the synchronization of EMB response within the front wheel group and the rear wheel group. Specifically, cross-coupling control can be used. In the synchronous control of four-wheel EMB, cross-coupling control is mainly applied between the front wheel group and the rear wheel group. The two EMBs in each wheel group share parameters such as clamping force and motor speed, calculate the error of each other (such as clamping force difference and motor speed difference), and adjust the control output according to the error to achieve synchronization effect. Independent control between the front wheel group and the rear wheel group can avoid the influence of the difference in front and rear wheel adhesion conditions on the dynamic stability of each other.

[0077] The embodiment of the application provides a four-wheel synchronous method based on EMB. The method is applied to EMB, and the method comprises the following steps: acquiring the response time length of each EMB to a target clamping force request sent by a main controller; for each EMB, if the response time length of the EMB is greater than a preset response time length threshold, the EMB is determined as a response lag EMB; the EMB with the shortest response time length is determined as a standard response EMB; the first clamping force of the standard response EMB, the current motor speed and the second clamping force of the response lag EMB are acquired respectively; the clamping force adjustment amount of the response lag EMB is determined according to the first clamping force of the standard response EMB and the second clamping force of the response lag EMB; the target motor speed of the response lag EMB is determined according to the first clamping force of the standard response EMB, the current motor speed, the second clamping force of the response lag EMB and a preset speed proportion adjustment coefficient; and the response lag EMB operates according to the clamping force adjustment amount and the target motor speed. According to the embodiment of the application, the response time length of each EMB is acquired, and the response lag EMB is determined, the motor speed and the clamping force output of the lag EMB are adjusted by taking the standard response EMB as a reference, the consistency of four-wheel response can be significantly improved, and the problems of poor braking stability and out-of-control in the extreme working condition caused by different responses in the prior art can be effectively solved. Through independent control of the front and rear wheel groups, the left-right swing of the vehicle body caused by uneven clamping force can be effectively reduced. In the condition of low adhesion road surface or split road surface, the lag EMB can be quickly compensated, the braking stability of the vehicle can be ensured, and the risk of out-of-control can be avoided. The motor speed and the clamping force output of the lag EMB are dynamically adjusted, the target clamping force request of the main controller can be quickly responded, and different vehicle running states and braking working conditions can be adapted. The speed proportion adjustment coefficient is adjusted according to the vehicle speed, the yaw rate and the acceleration, the robustness and the control precision of the system in complex working conditions are improved. The motor current and the clamping force change rate are monitored in real time, when the safety threshold is exceeded, the motor speed is dynamically adjusted and a warning signal is generated, and the motor damage caused by overload can be avoided. Through accurate adjustment of the response lag EMB, unnecessary energy consumption caused by different responses is reduced, the overall energy utilization efficiency of the system is optimized, and the service life of the equipment is prolonged.

[0078] It should be understood that although Figures 2 to 4 The steps in the flowchart of the method are shown in sequence according to the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other orders. Moreover, Figures 2 to 4At least one of the steps in the above method can include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but can be performed at different times, and the order of the steps or stages is not necessarily sequential, but can be performed alternately or alternately with at least one of the other steps or steps in the other steps.

[0079] It can be understood that the same / similar parts between each embodiment of the above method in the specification can be referred to each other, and each embodiment focuses on the difference from other embodiments, and the related part can be referred to the description of other method embodiments.

[0080] It can be understood by those skilled in the art that all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments of the method. Among them, any reference to memory, storage, database or other medium used in each embodiment provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0081] It should be pointed out that, in this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between such entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0082] It should also be pointed out that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for display, data for analysis, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties.

[0083] Each embodiment in the specification is described in a relevant manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the description of the method embodiment.

[0084] The technical features of the above embodiments can be combined in any way. In order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description.

[0085] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A four-wheel synchronization method based on EMB, characterized in that, The method is applied to EMBs, and the method comprises: acquiring a response time of each EMB to a target clamping force request sent by a main controller; for each EMB, if the response time of the EMB is greater than a preset response time threshold, determining that the EMB is a response-lag EMB; determining an EMB with the shortest response time as a standard response EMB; acquiring a first clamping force of the standard response EMB, a current motor speed of the standard response EMB, and a second clamping force of the response-lag EMB, respectively; determining a clamping force adjustment amount of the response-lag EMB according to the first clamping force of the standard response EMB and the second clamping force of the response-lag EMB; determining a target motor speed of the response-lag EMB according to the first clamping force of the standard response EMB, the current motor speed of the standard response EMB, the second clamping force of the response-lag EMB, and a preset speed proportional adjustment coefficient; the response-lag EMB operates according to the clamping force adjustment amount and the target motor speed; a formula for determining the clamping force adjustment amount of the response-lag EMB according to the first clamping force of the standard response EMB and the second clamping force of the response-lag EMB is: ΔF = F1-F2; wherein ΔF is the clamping force adjustment amount of the response-lag EMB, F1 is the first clamping force of the standard response EMB, and F2 is the second clamping force of the response-lag EMB; a formula for determining the target motor speed of the response-lag EMB according to the first clamping force of the standard response EMB, the current motor speed of the standard response EMB, the second clamping force of the response-lag EMB, and the preset speed proportional adjustment coefficient is: V1=V0+K(F1-F2); wherein V1 is the target motor speed, V0 is the current motor speed of the standard response EMB, F1 is the first clamping force of the standard response EMB, F2 is the second clamping force of the response-lag EMB, and K is the preset speed proportional adjustment coefficient.

2. The method of claim 1, wherein, the acquiring of the response time of each EMB to the target clamping force request sent by the main controller comprises: acquiring a first time when the main controller sends the target clamping force request and a second time when each EMB reaches the target clamping force; for each EMB, determining a difference between the second time and the second time when the EMB reaches the target clamping force as the response time of the EMB to the target clamping force request sent by the main controller.

3. The method of claim 1, wherein, the preset response time threshold is 50 ms.

4. The method of claim 1, wherein, the method further comprises: for each EMB, if the response time of the EMB is less than or equal to the response time threshold, determining that the EMB is a response-normal EMB.

5. The method of claim 1, wherein, the method further comprises: acquiring a clamping force change rate of the response-lag EMB; when the clamping force change rate is greater than a preset rate change safety threshold, dynamically reducing the motor speed of the response-lag EMB.

6. The method of claim 1, wherein, the method further comprises: the EMB control of the front wheel group and the rear wheel group is independent of each other.

7. A four-wheel synchronization system based on EMB, characterized in that, the system comprises a main controller and the EMB as claimed in any one of claims 1-6.

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