Brake-by-wire control system

Abstract

The application provides a brake-by-wire control system, and relates to the technical field of automobile electronics, which comprises a signal input module, a brake function module and a hydraulic control module which are sequentially connected in communication; the signal input module is used for collecting state observation data of a vehicle and sending the state observation data to the brake function module; the brake function module is used for determining a wheel cylinder pressure request signal based on the state observation data and sending the wheel cylinder pressure request signal to the hydraulic control module; and the hydraulic control module is used for outputting a target brake torque based on the wheel cylinder pressure request, and the target brake torque is used for controlling the vehicle to brake. The above-mentioned modules can improve the flexibility of the Onebox brake-by-wire control system.

Description

Technical Field

[0001] This application relates to the field of automotive electronics technology, and in particular to a brake-by-wire control system. Background Technology

[0002] Onebox is a vehicle safety braking solution, essentially the underlying electronic control system of a car. Onebox represents the future trend of brake-by-wire systems. Onebox offers advantages such as fast response, high functional integration, effective integration with energy recovery and autonomous driving functions, small footprint, and low cost.

[0003] Onebox boasts a high degree of functional integration, encompassing over a dozen functions including service braking, comfort-enhancing braking, differential braking for vehicle longitudinal and lateral stability control, assisted braking for autonomous driving, and delayed braking for energy recovery. Functionally, these functions are both independent and interdependent, requiring careful planning of their dependencies and priorities to ensure their proper operation. At the execution level, due to the complexity of real-world operating conditions, each wheel may receive multiple braking control commands simultaneously, necessitating effective arbitration of these commands to guarantee driving safety. This places extremely high demands on the Onebox system's software architecture. However, Onebox products are not yet fully widespread, and the related architectural design is still immature, resulting in a high degree of coupling and low flexibility in the existing Onebox system's software architecture. Summary of the Invention

[0004] This application provides a brake-by-wire control system that can rationally divide the functions of the Onebox brake-by-wire system to improve its flexibility.

[0005] In a first aspect, embodiments of this application provide a linear braking control system, including:

[0006] The signal input module, braking function module, and hydraulic control module are connected in sequence via communication.

[0007] The signal input module is used to collect vehicle status observation data and send the status observation data to the braking function module;

[0008] The braking function module is used to determine the wheel cylinder pressure request signal based on the state observation data, and send the wheel cylinder pressure request signal to the hydraulic control module;

[0009] The hydraulic control module is used to request the output of a target braking torque based on the wheel cylinder pressure, and the target braking torque is used to control the vehicle to brake.

[0010] In the brake-by-wire control system of this application embodiment, a signal input module, a braking function module, and a hydraulic control module are sequentially connected in communication. The braking function module determines the wheel pressure request of the vehicle, and the hydraulic control module outputs the braking torque corresponding to the wheel cylinder pressure request to achieve vehicle braking control. This enables the hydraulic control module to execute the target braking torque, and the braking function module to calculate the wheel pressure. The hydraulic control module is completely decoupled from the upstream functions and only serves as the pressure request execution module. This makes the module design relatively independent and does not affect each other, reducing the coupling degree of the brake-by-wire control system, improving flexibility, and facilitating distributed development and reuse. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of a linear braking control system provided in one embodiment of this application;

[0013] Figure 2 This is a schematic diagram of the structure of a linear braking control system provided in another embodiment of this application. Detailed Implementation

[0014] The features and exemplary embodiments of various aspects of this application will now be described in detail. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain this application and are not configured to limit this application. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples of this application.

[0015] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0016] To address the problems of the prior art, embodiments of this application provide a brake-by-wire control system. The linear braking control system provided in this application embodiment will be described below.

[0017] Figure 1 A schematic diagram of the structure of a linear braking control system provided in one embodiment of this application is shown. Figure 1 As shown, the system may specifically include:

[0018] The signal input module 1, the braking function module 2, and the hydraulic control module 3 are connected in sequence via communication.

[0019] Specifically, the communication connection may include wired and wireless connections, and this application does not limit it.

[0020] Signal input module 1 can be used to collect vehicle status observation data and send the status observation data to braking function module 2;

[0021] The aforementioned state observation data can be obtained by further estimating the sensor data collected by the sensors on the vehicle and the vehicle network data sent by other control systems on the vehicle, or it can be obtained by manually importing it into the signal input module 1, thereby enabling the signal input module 1 to acquire state observation data, etc. This application does not impose specific limitations on this.

[0022] Braking module 2 can be used to determine the wheel cylinder pressure request based on state observation data and send the wheel cylinder pressure request to hydraulic control module 3;

[0023] The aforementioned wheel cylinder pressure request can be a signal that includes the wheel cylinder pressure value.

[0024] Hydraulic control module 3 can be used to output a target braking torque based on wheel cylinder pressure requests, and the target braking torque is used to control the vehicle to brake.

[0025] When the vehicle brakes, the target braking torque is output to the corresponding wheel or drive shaft through the wheel cylinder. After receiving the wheel cylinder pressure request output by the braking function module 2, the wheel cylinder pressure value in the wheel cylinder pressure request needs to be converted into the target braking torque and then output to the wheel to complete the vehicle braking control.

[0026] This application provides a brake-by-wire control system that sequentially connects a signal input module 1, a braking function module 2, and a hydraulic control module 3. The braking function module 2 determines the wheel pressure request of the vehicle, and the hydraulic control module 3 outputs the braking torque corresponding to the wheel cylinder pressure request to achieve vehicle braking control. This allows the hydraulic control module 3 to execute the target braking torque, while the braking function module 2 calculates the wheel pressure. By completely decoupling the hydraulic control module 3 from the upstream functions, it serves only as the pressure request execution module. This makes the module design relatively independent and does not affect each other, reducing the coupling degree of the brake-by-wire control system, improving flexibility, and facilitating distributed development and reuse.

[0027] In one embodiment of this application, the signal input module 1 includes a signal acquisition submodule 10 and an estimation submodule 11;

[0028] The signal acquisition submodule 10 is used to acquire basic data collected on the vehicle, including sensor data collected by sensors on the vehicle and vehicle network data.

[0029] The sensor data includes wheel speed sensor signals, such as wheel speed and wheel acceleration; inertial navigation signals, such as vehicle acceleration and angular velocity; pressure sensor signals, such as electric master cylinder pressure; and pedal displacement signals. The vehicle network includes steering system signals, such as steering wheel angle and angular velocity; and powertrain system signals, such as engine drive torque, gear position, and accelerator pedal signals.

[0030] It should be noted that, in addition to collecting basic data, the signal acquisition submodule 10 is also responsible for preprocessing the signal to facilitate its use by the subsequent braking function module 2, such as filtering, range checking, unit and type conversion, and fault diagnosis. The processed signal will be synchronously distributed to different submodules in the braking function module 2.

[0031] The estimation submodule 11 is used to estimate the vehicle's state observation data based on the basic data and output the state observation data to the braking function module 2.

[0032] This module is responsible for estimating vehicle observation data, providing a basis for the longitudinal and lateral control of the vehicle. The inputs to the estimation submodule 11 include wheel speed, wheel acceleration, front wheel steering angle, vehicle yaw rate, and vehicle longitudinal / lateral acceleration. The outputs of the estimation submodule 11 include longitudinal and lateral vehicle speeds, tire sideslip angle, center of gravity sideslip angle, tire load force, road adhesion coefficient, actual slip ratio and target slip ratio, vehicle mass, road gradient, and caliper braking torque.

[0033] The state observation module is the most important link in ensuring that all functions in the brake-by-wire control system can be realized. It outputs the estimated state observation data to all sub-functional modules in the braking function module 2, including the service brake sub-module 23, the automatic driving sub-module 22, and the differential brake sub-module 21.

[0034] In this embodiment, state observation data is obtained through the estimation submodule 11 and signal acquisition submodule 10 in the signal input module 1, providing a calculation basis for the braking function module 2. At the same time, the signal input module 1 can be decoupled from its downstream modules, which is highly flexible.

[0035] In one embodiment of this application, the braking function module 2 includes a service brake submodule 23, an automatic driving submodule 22, and a differential brake submodule 21. The service brake submodule 23, the automatic driving submodule 22, and the differential brake submodule 21 are all communicatively connected to the signal input module 1, and the differential brake submodule 21 is communicatively connected to the hydraulic control module 3.

[0036] The service brake submodule 23 can generate a service brake signal when the state observation data reaches the preset service brake triggering conditions, and output the service brake signal to the differential brake submodule 21;

[0037] Service braking is the braking process when the driver actively presses the brake pedal during vehicle operation. It aims to respond to the driver's request and meet comfort requirements. During the service braking process, the torque output from the wheel cylinders to all wheels is consistent.

[0038] Since the service brake submodule 23 includes multiple functional units, and each functional unit has its corresponding triggering condition, the service brake triggering condition includes the triggering conditions of all functional units in the service brake submodule 23. Accordingly, each functional unit has a corresponding service brake signal. Specifically, for the service brake triggering condition and the service brake signal, please refer to the following embodiment.

[0039] In one embodiment of this application, the service brake submodule 23 includes a plurality of service brake units 231, which are communicatively connected to the signal input module 1 and the torque arbitration unit 213, respectively.

[0040] The service braking unit 231 is used to generate a third request signal when the state observation data reaches the service braking trigger condition, and output the third request signal to the torque arbitration unit 213. The third request signal includes the third torque request signal of the corresponding wheel and the third activation flag corresponding to the service braking unit 231.

[0041] The aforementioned service braking unit 231 includes a caliper heat fade compensation unit (FBS), a brake warning unit (RAB), a brake assist system unit (BAS), a downhill speed control unit (HDC), a hill start assist system unit (HSA), and a comfort parking assist unit (CST), etc.

[0042] Taking the caliper heat fade compensation unit as an example, the service braking trigger condition for the caliper heat fade compensation unit is that the caliper temperature reaches a preset temperature value, whereby the caliper temperature can be obtained through state observation data. The trigger conditions for the other service braking units 231 are not described in detail here.

[0043] The third torque request indicates that the service brake unit 231, corresponding to the third request signal, outputs a torque value to the vehicle after activation, so that the wheel cylinders of the vehicle respond, thereby controlling the vehicle. The third activation mark indicates that the corresponding service brake unit 231 has been activated, and it corresponds one-to-one with the third torque request. For example, after the caliper heat fade compensation unit is activated, a third request signal is issued, in which the fourth torque request indicates that the torque value requested by the caliper heat fade compensation unit is requested, so as to realize the control of the vehicle by the caliper heat fade compensation unit; the third activation mark indicates that the torque value request is issued by the caliper heat fade compensation unit after activation, and it corresponds to the torque value request.

[0044] The autonomous driving submodule 22 can be used to generate an autonomous driving signal when the state observation data reaches the preset autonomous driving triggering conditions, and output the autonomous driving signal to the differential braking submodule 21;

[0045] Autonomous driving typically requires a brake-by-wire control system to achieve speed and acceleration tracking control. The triggering conditions for autonomous driving can be determined by perception data from the state observation data, which is used to determine whether to trigger the autonomous driving unit 221 in the autonomous driving submodule 22. This perception data is detected by the vehicle's perception systems, such as data detected by cameras or vehicle radar. Autonomous driving signals include an autonomous driving torque request and an autonomous driving activation flag. The autonomous driving torque request indicates a torque value request issued by the corresponding autonomous driving unit 221, and the autonomous driving activation flag indicates that the torque request was sent by the corresponding autonomous driving unit 221.

[0046] Specifically, in one embodiment, the autonomous driving submodule 22 includes a speed and acceleration control unit 222 and a plurality of autonomous driving units 221, all of which are communicatively connected to the speed and acceleration control unit 222.

[0047] The autonomous driving unit 221 is used to generate an autonomous driving activation flag and a control target request when the state observation data reaches the autonomous driving triggering condition, and send them to the speed and acceleration control unit 222. The control target request includes a speed request or an acceleration request. The autonomous driving activation flag is used to activate the corresponding speed and acceleration control unit 222 based on the control target request.

[0048] The autonomous driving unit 221 includes an AEB function unit, an APA function unit, and an AVP function unit. APA stands for Automatic Parking Assist, AVP stands for Automatic Valet Parking, and AEB stands for Automatic Emergency Braking.

[0049] Autonomous driving typically requires braking systems to achieve speed and acceleration tracking control, such as AEB, APA, and AVP. This system sets up "AEB functional units," "APA functional units," and "AVP functional units" for these functions, mainly for condition judgment and function configuration, and outputting their respective autonomous driving activation flags and control target requests, which include speed requests or acceleration requests.

[0050] The speed and acceleration control unit 222 is used to perform closed-loop control on the control target request based on the autonomous driving activation flag, obtain the autonomous driving torque request, and send the autonomous driving torque request and the autonomous driving activation flag to the torque arbitration unit 213.

[0051] The speed and acceleration control unit 222 performs closed-loop control of speed and acceleration and outputs a braking torque request. This unit also needs to perform necessary arbitration to ensure the reasonableness and uniqueness of the request. The priority of the arbitration is determined based on real-time vehicle conditions. For example, when the AVP function is running (the system is in speed tracking control mode), if the perception system detects an obstacle rapidly approaching, the low-speed AEB function is activated. In this vehicle condition, this function has higher priority, so the system needs to switch from speed tracking control to torque tracking control. Ultimately, torque tracking control still reflects speed or acceleration control.

[0052] The differential braking submodule 21 can generate a differential braking signal when the state observation data reaches the preset differential braking triggering conditions, and arbitrate the differential braking signal, the service braking signal and the automatic driving signal to obtain the wheel cylinder pressure request, and output the wheel cylinder pressure request to the hydraulic control module 3.

[0053] In this embodiment, differential braking refers to controlling the braking force of each of the four wheels separately, so that the vehicle generates a more reasonable braking force distribution and yaw moment than the driver's braking request, achieving the goal of both fully responding to the driver's request and ensuring vehicle stability. For example, during emergency braking, the driver requests a very large braking force. If the braking force is output according to this request, the tires will lose lateral force due to sudden locking. At this time, the anti-lock braking system (ABS) function is activated, and the system actively reduces the braking force to prevent the tires from locking up. As another example, when the vehicle has an oversteer tendency to become unstable, the active yaw control system function is activated. Even if the driver does not press the brake pedal, the system still applies a certain amount of force to the outer wheels individually to prevent oversteer.

[0054] Since the differential braking submodule 21 includes a slip ratio control unit 211 and a non-slip ratio control unit 212, the slip ratio control unit 211 determines whether the differential braking trigger condition is met based on the slip ratio of each wheel. In the non-slip ratio control unit 212, the trigger condition corresponding to the subunits it contains determines whether the non-slip ratio control unit 212 is triggered. For the specific triggering logic, please refer to the following embodiment; it will not be elaborated upon here.

[0055] Since the differential braking signal, service braking signal, and automatic driving signal may be triggered simultaneously and require simultaneous response, and the vehicle cannot respond to all three signal requests at the same time, arbitration is necessary to achieve simultaneous response to all three signals. Accordingly, after arbitrating the three signals, a wheel cylinder pressure request is obtained, causing the hydraulic control module 3 to respond to its wheel cylinder pressure request and output the corresponding torque value to each wheel.

[0056] Specifically, in one embodiment of this application, the differential braking submodule 21 includes a slip ratio control unit 211, a non-slip ratio control unit 212, and a torque arbitration unit 213, wherein the slip ratio control unit 211 and the non-slip ratio control unit 212 are both communicatively connected to the torque arbitration unit 213;

[0057] The slip ratio control unit 211 can be used to generate a slip ratio request signal for each wheel on the vehicle based on the actual slip ratio and the target slip ratio when the actual slip ratio is less than or equal to the preset slip ratio, and send it to the torque arbitration unit 213.

[0058] The slip ratio control unit 211 detects the actual slip ratio of the wheel and then determines whether to trigger a specific slip ratio function subunit 2111 within the slip ratio control unit 211 by comparing the actual slip ratio with a preset slip ratio. Correspondingly, the number of slip ratio request signals corresponds to the number of slip ratio function subunits 2111.

[0059] The nonslip ratio control unit 212 can be used to generate a nonslip ratio request signal for each wheel on the vehicle based on state observation data and send it to the torque arbitration unit 213;

[0060] In this embodiment, functions that belong to differential braking and are not triggered by slip ratio are classified as non-slip ratio control unit 212. The non-slip ratio request signal is obtained by triggering the triggering condition corresponding to each specific non-slip ratio function subunit 2121 in the non-slip ratio control unit 212.

[0061] The torque arbitration unit 213 can be used to receive slip ratio request signals, non-slip ratio request signals, automatic driving signals and service braking signals for arbitration, obtain target torque request signals, and convert the target torque request signals into wheel cylinder pressure request signals.

[0062] Since the vehicle cannot simultaneously respond to multiple torque request signals sent by the service braking submodule 23, the automatic driving submodule 22, and the differential braking submodule 21, and to ensure the rationality and uniqueness of the final torque command, the torque arbitration unit 213 receives the service braking signal sent by the service braking submodule 23, the automatic driving signal sent by the automatic driving submodule 22, and the slip ratio request signal and non-slip ratio request signal sent by the differential braking submodule 21. It then arbitrates these signals, calculating the final torque of each wheel as the target torque request signal, which is then converted into a wheel cylinder pressure request signal. The target torque request signal includes the torque request signal for each wheel.

[0063] In this embodiment, by setting up a slip ratio control unit 211, a non-slip ratio control unit 212, and a torque arbitration unit 213, the uniqueness and rationality of the target torque request signal can be guaranteed.

[0064] In one embodiment of this application, the slip ratio control unit 211 includes a slip ratio arbitration subunit 2112, a slip ratio controller 2113, and a plurality of slip ratio functional subunits 2111;

[0065] The slip ratio function subunit 2111 can be used to generate a set of first request signals when the actual slip ratio is less than or equal to the preset slip ratio, and send the first request signals to the slip ratio arbitration subunit 2112. Each first request signal in the set of first request signals includes a first activation flag corresponding to the slip ratio function subunit 2111.

[0066] The slip ratio control unit 211 mentioned above may include an ABS+EBD functional unit, a TCS functional unit, and an AYC+ARP functional unit, wherein ABS represents anti-lock braking system, EBD represents electronic brake force distribution, TCS represents traction control system, AYC represents active yaw control system, and ARP represents active rollover protection.

[0067] Since ABS and EBD are both longitudinal control functions under braking conditions and are complementary (ABS is braking control under extreme conditions, and EBD is braking control under non-extreme conditions), these two functions are grouped into one module, namely the "ABS+EBD functional unit". ABS and EBD each generate their own activation signals. Since the two activation signals are mutually exclusive, there is no need for slip ratio arbitration. TCS is longitudinal control under driving conditions and is assigned to a separate module, namely the "TCS functional unit". Both AYC and ARP are lateral control (yaw control), therefore they are grouped into one module, namely "AYC+ARP functional unit state observation data". Since differential braking brakes each wheel separately, each wheel has a corresponding actual slip ratio, preset slip ratio, and target slip ratio. When generating the slip ratio request signal, the ABS+EBD functional unit is used as an example for explanation. Since the ABS and EBD functions are mutually exclusive, only one function will be activated for braking. Therefore, the activation of ABS is used as an example for explanation. When the ABS+EBD functional unit detects that the actual slip ratio of one or more wheels of the vehicle is less than the preset slip ratio, the ABS+EBD functional unit is activated and sends the first activation flag indicating that the ABS+EBD functional unit has been activated to the slip ratio arbitration subunit 2112.

[0068] The aforementioned set of first request signals includes a first request signal for each wheel, and the first activation marker in the first request signal indicates which slip ratio function subunit 2111 issued the first request signal and the target it is applied to. For example, if the ABS+EBD function unit issues the first request signal, the first activation marker could be the ABS+EBD function unit and the right rear wheel.

[0069] The slip ratio arbitration subunit 2112 can be used to sort and mark multiple sets of first request signals based on the preset priority and first activation flag of multiple slip ratio functional subunits 2111, and input the marked first request signals to the slip ratio controller 2113 in sequence.

[0070] Under certain special operating conditions, multiple functions among AYC, ARP, ABS, EBD, and TCS can be triggered simultaneously, with the priority defined as follows: ARP > AYC > ABS = TCS > EBD. There are also cases where different wheels trigger different functions, resulting in different target slip ratios. Therefore, it is necessary to first arbitrate the target slip ratio for each wheel, using the arbitration result as the target. Thus, a "slip ratio arbitration subunit 2112" is designed in the system. This slip ratio arbitration subunit 2112 simultaneously receives the first activation flags and target slip ratio signals from TCS, ABS, EBD, AYC, and ARP functions. After arbitration according to priority, it re-marks and sorts the first activation flags in the first request signals of each wheel, and finally sends the sorted first request signals to the slip ratio controller 2113.

[0071] For example, if ARP and AYC are triggered simultaneously and torque needs to be applied to the same wheel, the slip ratio arbitration subunit 2112 will receive the target slip ratios of ARP and AYC at the same time. Since ARP has a higher priority than AYC, the first activation flag in the first request signal sent by ARP will be marked as 1 again, and the second activation flag in the first request signal sent by AYC will be marked as 2 again. Based on the flags 1 and 2, the first request signals sent by ARP and AYC will be sorted. Finally, the first request signals sent by ARP and AYC will be input to the slip ratio controller 2113 in sequence according to the sorting.

[0072] The slip ratio controller 2113 can be used to determine the first torque request signal corresponding to each wheel in each group of first request signals when the actual slip ratio reaches the target slip ratio.

[0073] The slip ratio controller 2113 is responsible for calculating the braking torque required to maintain the actual slip ratio of each tire at the target slip ratio, and generating a first torque request signal containing that braking torque. Additionally, the slip ratio controller 2113 provides a drive torque limit to prevent mutual wear between the braking and drive systems.

[0074] In this embodiment, by setting up a slip ratio arbitration subunit 2112, a slip ratio controller 2113, and multiple slip ratio functional subunits 2111, multiple first request signals issued by multiple slip ratio functional subunits 2111 can be arbitrated, preventing multiple first request signals from acting on the same wheel at the same time and causing response confusion, thereby realizing the reasonable division, classification, and decoupling of each functional subunit.

[0075] In one embodiment of this application, the differential braking submodule 21 further includes a drive limiting unit 214, and the service braking submodule 23, the automatic driving submodule 22, the slip ratio control unit 211, and the non-slip ratio control unit 212 are all communicatively connected to the drive limiting unit 214.

[0076] The drive limiting unit 214 can be used to receive service braking signals, automatic driving signals, slip ratio request signals and non-slip ratio request signals, and obtain front and rear axle torque limiting requests and suspension adjustment requests. Both front and rear axle torque limiting requests and suspension adjustment requests are used to limit vehicle body sway.

[0077] To reduce simultaneous losses during driving and braking, the drive torque output needs to be appropriately reduced when the braking system is operating. Under certain conditions (such as CTC and TCS), a torque increase request may also be issued. Considering vehicle comfort and stability, the suspension damping characteristics need to be altered under high dynamic conditions to limit body roll. Therefore, a "drive limit unit 214" is provided. This module receives activation signals and torque limit signals from all functions, integrates them, and outputs front and rear axle torque limit requests and suspension adjustment requests.

[0078] In one embodiment of this application, the non-slip rate request signal includes a second request signal;

[0079] The non-slip ratio control unit 212 includes multiple non-slip ratio functional subunits 2121. Each non-slip ratio functional subunit 2121 is used to generate a set of second request signals when the state observation data reaches the preset non-slip ratio function triggering condition, and send the second request signals to the torque arbitration unit 213. Each second request signal in the set of second request signals includes a second torque request signal corresponding to the wheel and a second activation flag corresponding to the non-slip ratio functional subunit 2121.

[0080] In this embodiment, the non-slip ratio control unit 212 includes a CTC functional unit, a CBC functional unit, and a CCO functional unit, wherein CTC represents cornering traction control, CBC represents cornering braking force control, and CCO represents low-speed off-road cruise.

[0081] The triggering conditions for the CTC function unit include triggering the CTC function unit when the traction force exceeds a preset traction force while the vehicle is turning. The triggering conditions for the CBC function unit include triggering the CBC function unit when the braking force exceeds a preset braking force while the vehicle is turning. The triggering conditions for each unit in the non-slip ratio control unit 212 can be set by the user, and this application does not impose any restrictions on this.

[0082] CTC and CBC functions typically employ open-loop control strategies, eliminating the need for slip ratio closed-loop control. Therefore, separate modules, "CTC Functional Unit" and "CBC Functional Unit," are designed. These two units output their respective second activation flag and second torque request signals.

[0083] It should be noted that the CCO function also requires slip ratio closed-loop control, but due to the complexity of the operating conditions, a separate control logic is needed. Furthermore, when this function is activated, other functions must be disabled, making the aforementioned "slip ratio controller 2113" unusable. Therefore, a separate unit, the "CCO function unit," is designed, containing an independent slip ratio controller 2113. In addition to outputting the second torque request signal and the second activation flag, this CCO function unit also outputs a drive torque limit signal.

[0084] It should also be noted that the generation logic of the second torque request signal and the second activation flag corresponding to the CCO functional unit is the same as the generation logic of the first torque request signal and the first activation flag in the slip ratio control unit 211, which will not be elaborated here. However, since the target slip ratio in the CCO functional unit is preset by the CCO functional unit, it is not necessary to obtain the target slip ratio through the estimation submodule 11. It can be considered that the CCO functional unit does not need to perform slip ratio closed-loop control. Therefore, the CCO functional unit, the CTC functional unit, and the CBC functional unit are classified together as non-slip ratio control unit 212.

[0085] In this embodiment, by setting a non-slip ratio control unit 212 and sending the second request signal generated by the non-slip ratio control unit 212 to the torque arbitration unit 213, the differential braking function controlled by the non-slip ratio can be reasonably allocated, and the addition or deletion of the non-slip ratio control unit 212 can be realized, thereby improving the flexibility of the braking system.

[0086] In one embodiment of this application, the torque arbitration unit 213 further includes an energy recovery subunit 2231, which is used to obtain a remaining torque request and convert the remaining torque request into a wheel cylinder pressure request. The remaining torque request includes a remaining torque, which is the difference between the target torque included in the target torque request signal and the pre-acquired braking torque.

[0087] In this embodiment, the basic principle of energy recovery is to force the drive motor to operate in generator mode during braking, which consumes the vehicle's kinetic energy to produce a braking effect, while simultaneously converting the kinetic energy into electrical energy for recovery. When braking occurs, this module delays and reduces the intervention of the braking system, making full use of the motor's counter-torque to create a braking effect, and outputs the remaining torque request to achieve energy saving and reduced wear.

[0088] The remaining torque request refers to the remaining value after subtracting the braking torque provided by the motor's reverse drag from the target torque included in the arbitrated target torque request signal. For vehicles without energy recovery function, the energy recovery module can be removed, and the arbitrated target torque request signal can be directly converted into a wheel cylinder pressure request and output to the hydraulic control module 3. For vehicles with energy recovery function, the remaining torque request is directly converted into a wheel cylinder pressure request and output to the hydraulic control module 3.

[0089] In this embodiment, by setting an energy recovery subunit 2231 in the torque arbitration unit 213, the energy recovery of the vehicle can be realized. At the same time, the energy recovery subunit 2231 can be added or removed to improve the flexibility of the brake-by-wire control system.

[0090] In another embodiment of this application, the brake-by-wire control system further includes an output signal processing module. The signal output module is communicatively connected to the braking function module 2 and the hydraulic control module 3, respectively. Specifically, the signal output module is communicatively connected to the service brake submodule 23, the automatic driving submodule 22, the differential brake submodule 21, and the drive limiting unit 214 in the braking function module 2.

[0091] The output signal processing module, serving as the output interface of the entire brake-by-wire control system, collects and integrates the output signals from other modules. This integration includes signal filtering, unit and type conversion, range checking, and fault diagnosis. The processed signal is then sent to other application layer functions on the vehicle or transmitted to the vehicle network via CAN.

[0092] Figure 2 A schematic diagram of the structure of a linear braking control system provided in another embodiment of this application is shown. Figure 2As shown, the input signal processing module in this system is the signal acquisition submodule 10 in this application; the state observation module is the estimation submodule 11 in this application; the differential braking function area is the differential braking submodule 21 in this application; the automatic driving function area is the automatic driving submodule 22 in this application; the service braking function area is the service braking submodule 23 in this application; the ABS+EBD function unit, TCS function unit, and AYC+ARP function unit are the slip ratio function subunit 2111 in this application; the target slip ratio arbitration module is the slip ratio arbitration subunit 2112 in this application; the slip ratio controller is the slip ratio controller 2113 in this application; the torque arbitration module is the torque arbitration unit 213 in this application; and the energy recovery is the energy recovery subunit 2231 in this application. The TC function module, CBC function module, and CCO function module are the non-slip ratio function sub-unit 2121 in this application; the drive torque limiting and suspension request module are the drive limiting unit 214 in this application; the service braking function area is the service braking sub-module 23 in this application; the automatic driving function area is the automatic driving sub-module 22 in this application; the FBS function, RAB function, HSA function, BAS function, and HDC function are the service braking unit 231 in this application; the AEB function, AVP function, and APA function are the automatic driving unit 221 in this application; the speed and acceleration control unit is the speed and acceleration control unit 222 in this application; the hydraulic control module is the hydraulic control module 3 in this application; and the output signal processing module is the output signal processing module in this application.

[0093] The embodiments described above are not exhaustive and do not limit the invention to specific examples. Clearly, many modifications and variations can be made based on the above description. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to effectively utilize this application and its modifications. This application is limited only by the claims and their full scope and equivalents.

Claims

1. A brake-by-wire control system, characterized in that, include: The signal input module, braking function module, and hydraulic control module are connected in sequence via communication. The signal input module is used to collect vehicle status observation data and send the status observation data to the braking function module; The braking function module is used to determine a wheel cylinder pressure request signal based on the state observation data, and send the wheel cylinder pressure request signal to the hydraulic control module. The wheel cylinder pressure request is a signal that includes the wheel cylinder pressure value. The hydraulic control module is used to convert the wheel cylinder pressure value in the wheel cylinder pressure request into a target braking torque and output it to the wheel. The target braking torque is used to control the vehicle to brake. The braking function module includes a service brake submodule, an automatic driving submodule, and a differential brake submodule. The service brake submodule, the automatic driving submodule, and the differential brake submodule are all communicatively connected to the signal input module, and the differential brake submodule is communicatively connected to the hydraulic control module. The service brake submodule is used to generate a service brake signal when the state observation data reaches the preset service brake triggering condition, and output the service brake signal to the differential brake submodule. The autonomous driving submodule is used to generate an autonomous driving signal when the state observation data reaches the preset autonomous driving triggering conditions, and output the autonomous driving signal to the differential braking submodule. The differential braking submodule is used to generate a differential braking signal when the state observation data reaches the preset differential braking triggering conditions, and to arbitrate the differential braking signal, the service braking signal and the automatic driving signal to obtain a wheel cylinder pressure request, and output the wheel cylinder pressure request to the hydraulic control module.

2. The brake-by-wire control system as described in claim 1, characterized in that, The signal input module includes a signal acquisition submodule and an estimation submodule; The signal acquisition submodule is used to acquire basic data collected on the vehicle, including sensor data collected by sensors on the vehicle and vehicle network data. The estimation submodule is used to estimate the vehicle's state observation data based on the basic data, and output the state observation data to the braking function module.

3. The brake-by-wire control system as described in claim 1, characterized in that, The state observation data includes the actual slip ratio and the target slip ratio; the differential braking signal includes a slip ratio request signal and a non-slip ratio request signal; The differential braking submodule includes a slip ratio control unit, a non-slip ratio control unit, and a torque arbitration unit. Both the slip ratio control unit and the non-slip ratio control unit are communicatively connected to the torque arbitration unit. The slip ratio control unit is configured to generate a slip ratio request signal for each wheel on the vehicle based on the actual slip ratio and the target slip ratio when the actual slip ratio is less than or equal to a preset slip ratio, and send it to the torque arbitration unit. The non-slip ratio control unit is used to generate a non-slip ratio request signal for each wheel on the vehicle based on the state observation data, and send it to the torque arbitration unit. The torque arbitration unit is used to receive the slip ratio request signal, the non-slip ratio request signal, the automatic driving signal and the service braking signal, arbitrate them to obtain the target torque request signal, and convert the target torque request signal into a wheel cylinder pressure request signal.

4. The brake-by-wire control system as described in claim 3, characterized in that, The slip ratio request signal includes a first request signal; The slip ratio control unit includes a slip ratio arbitration subunit, a slip ratio controller, and multiple slip ratio functional subunits; The slip ratio function subunit is used to generate a set of first request signals when the actual slip ratio is less than or equal to the preset slip ratio, and send the first request signals to the slip ratio arbitration subunit. Each of the first request signals in the set of first request signals includes a first activation flag corresponding to the slip ratio function subunit. The slip ratio arbitration subunit is used to sort and mark multiple sets of the first request signals based on the preset priority of the multiple slip ratio functional subunits and the first activation flag, and input the marked first request signals to the slip ratio controller in sequence. The slip ratio controller is used to determine the first torque request signal corresponding to each wheel in each group of the first request signals when the actual slip ratio reaches the target slip ratio, wherein the first torque request signal is included in the first request signal.

5. The brake-by-wire control system as described in claim 3, characterized in that, The differential braking submodule also includes a drive limiting unit, and the service braking submodule, the automatic driving submodule, the slip ratio control unit, and the non-slip ratio control unit are all communicatively connected to the drive limiting unit; The drive limiting unit is used to receive the service braking signal, the automatic driving signal, the slip ratio request signal, and the non-slip ratio request signal, and to obtain the front and rear axle torque limiting request and the suspension adjustment request. Both the front and rear axle torque limiting request and the suspension adjustment request are used to limit vehicle body sway.

6. The brake-by-wire control system as described in claim 3, characterized in that, The non-slip rate request signal includes a second request signal; The non-slip ratio control unit includes multiple non-slip ratio functional sub-units. Each non-slip ratio functional sub-unit is used to generate a set of second request signals when the state observation data reaches a preset non-slip ratio function trigger condition, and send the second request signals to the torque arbitration unit. Each second request signal in the set of second request signals includes a second torque request signal corresponding to the wheel and a second activation flag corresponding to the non-slip ratio functional sub-unit.

7. The brake-by-wire control system as described in claim 3, characterized in that, The torque arbitration unit further includes an energy recovery subunit, which is used to obtain the remaining torque request and convert the remaining torque request into the wheel cylinder pressure request. The remaining torque request includes the remaining torque, which is the difference between the target torque included in the target torque request signal and the pre-acquired braking torque.

8. The brake-by-wire control system as described in claim 1, characterized in that, The service braking signal includes a third request signal; the differential braking submodule includes a torque arbitration unit; The service brake submodule includes multiple service brake units, which are communicatively connected to the signal input module and the torque arbitration unit, respectively. The service braking unit is used to generate a third request signal when the state observation data reaches the service braking trigger condition, and output the third request signal to the torque arbitration unit. The third request signal includes a third torque request signal for the corresponding wheel and a third activation flag corresponding to the service braking unit.

9. The brake-by-wire control system as described in claim 1, characterized in that, The autonomous driving signals include an autonomous driving torque request and an autonomous driving activation flag; the differential braking submodule includes a torque arbitration unit; The autonomous driving submodule includes a speed and acceleration control unit and multiple autonomous driving units, all of which are communicatively connected to the speed and acceleration control unit. The autonomous driving unit is used to generate an autonomous driving activation flag and a control target request when the state observation data reaches the autonomous driving triggering condition, and send them to the speed and acceleration control unit. The control target request includes a speed request or an acceleration request. The autonomous driving activation flag is used to activate the corresponding speed and acceleration control unit based on the control target request. The speed and acceleration control unit is used to perform closed-loop control on the control target request based on the autonomous driving activation flag, obtain the autonomous driving torque request, and send the autonomous driving torque request and the autonomous driving activation flag to the torque arbitration unit.

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