Method and system for controlling wheel slip in a vehicle brake system using BbW technology

Abstract

A method (500) for controlling wheel slip in a vehicle braking system includes the steps of: receiving (501) information representative of the vehicle and information representative of an estimate of the vehicle's state by an input interface module of a slip control module; and outputting (502) the input wheel slip control information by the input interface module. The method includes a step (503) of determining wheel slip control parameters by a parameter self-loading module of the input interface module based on representative information of the vehicle and representative information of the vehicle state; a step (505) of determining a plurality of wheel slip control enable signals by a plurality of wheel slip control enable modules of the slip control module based on the received input wheel slip control information and the received wheel slip control parameters; and a step (506) of determining, by each closed-loop wheel slip control module of the plurality of closed-loop wheel slip control modules of the slip control module, a set value of a control variable to be applied to each vehicle corner based on a defined slip set value and an estimated wheel slip value, thereby minimizing an error between the defined slip set value and the estimated wheel slip. [Figure 5]

Description

Technical Field

[0005] , ,

[0006]

[0001] The present invention relates to a braking system for a vehicle, and more particularly to a method and a system for controlling wheel slip in a braking system using the B-b-W technology of the vehicle.

Background Art

[0002] Wheel slip control is very important in a vehicle, and is added to the configuration of the braking system. In this regard, it is necessary to ensure the optimization and flexibility of control at a high level.

[0003] In a conventional braking system characterized by an operating circuit having a large number of valves, brake management is usually performed by a discrete cycle control algorithm (application and release of periodic brake requests). However, for example, it does not allow separation between vehicle wheel slip control and continuous force modulation control of an actuator adapted to apply a braking action to the wheel, thereby actually limiting all kinds of optimizations and flexibility of the whole method for controlling the braking system to achieve optimal performance in terms of wheel control. At the same time, there is an architecture that limits tuning technology to empirical methods.

[0004] Very recently, innovative architectures have proposed braking systems equipped with electronic braking systems having B-b-W (“brake-by-wire”, braking by electrical connection) technology. In this system, for example, the braking operation of a brake caliper on a wheel is achieved by using one or more electromechanical or electrohydraulic actuators.

[0005] However, based on the foregoing considerations regarding conventional braking systems, the method for controlling the slip of a vehicle wheel that can be used in a conventional braking system is not optimal for application in a braking system equipped with an electronic braking system using B-b-W technology.

[0006] Today, even in braking systems equipped with electronic braking systems using BbW technology, there is a need to define specific optimized modes for controlling the slip of the vehicle's wheels, and it is possible to configure these control modes as a function of evaluating the state of one or more wheels and / or the vehicle itself. [Overview of the project]

[0007] The object of the present invention is to ensure greater flexibility and further privilege and optimization of wheel slip control, responsiveness and performance, and brake comfort by devising and making available a method for controlling wheel slip in a vehicle's braking system that enables at least partial avoidance of the drawbacks described above with reference to the prior art, and in particular enables the possibility of configuring such control modes as a function of evaluating the state of one or more wheels and / or the vehicle itself.

[0008] Such objectives are achieved by the method described in claim 1.

[0009] The present invention further relates to a system for controlling wheel slip in a vehicle's braking system.

[0010] Further advantageous embodiments are subject to the dependent claims. [Brief explanation of the drawing]

[0011] Further features and advantages of the methods and systems according to the present invention will become apparent from the following description of preferred embodiments, given by explanatory and non-limiting examples with reference to the accompanying figures.

[0012] [Figure 1] Figure 1 shows a vehicle and electronic brake system using brake-by-wire technology, as illustrated by a block chart, in which a system for controlling wheel slip in the brake system of the vehicle, which is the subject of the present invention, can be employed. [Figure 2] Figure 2 shows the vehicle and the electronic brake system with brake-by-wire technology from Figure 1, along with details of each of their internal components, using a block chart. [Figure 3A] Figure 3A shows, by block chart, a system for controlling vehicle wheel slip according to various embodiments of the present invention. [Figure 3B] Figure 3B shows, through various block charts, a system for controlling vehicle wheel slip according to different embodiments of the present invention. [Figure 3C] Figure 3C shows, by block chart, a system for controlling vehicle wheel slip according to various embodiments of the present invention. [Figure 4A] Figure 4A schematically shows the components of a system for controlling wheel slip in a vehicle brake system according to the present invention. [Figure 4B] Figure 4B schematically shows the components of a system for controlling wheel slip in a vehicle brake system according to the present invention. [Figure 4C] Figure 4C schematically shows the components of a system for controlling wheel slip in a vehicle brake system according to the present invention. [Figure 4D] Figure 4D schematically shows the components of a system for controlling wheel slip in a vehicle brake system according to the present invention. [Figure 4E] Figure 4E schematically shows the components of a system for controlling wheel slip in a vehicle brake system according to the present invention. [Figure 4F] Figure 4F schematically shows the components of a system for controlling wheel slip in a vehicle brake system according to the present invention. [Figure 4G]Figure 4G schematically shows each component of a system for controlling wheel slip in a vehicle braking system according to the present invention. [Figure 5] Figure 5 shows, by means of a block diagram, a method for controlling wheel slip in a vehicle braking system according to an embodiment of the present invention; and [Figure 6] Figure 6 shows, by means of a block chart, an example of the operation of components of a system for controlling wheel slip in a vehicle braking system. DETAILED DESCRIPTION OF THE INVENTION

[0013] Referring now to the foregoing figures, reference numeral 100 generally designates a system for controlling wheel slip in a vehicle braking system (hereinafter also simply referred to as a "system") according to the present invention.

[0014] Note that equal or similar elements in the figures are denoted by the same numerical or alphanumerical references.

[0015] As used herein, a "vehicle" shown only schematically in the figures is also of a commercial type and means any vehicle or motorcycle having two, three, four, or more wheels.

[0016] Furthermore, a "braking system" means the entirety of all components (mechanical and / or electrical or electronic, as well as brake fluid) that contribute to the generation of the service brakes of a vehicle or the generation of the parking brakes of a vehicle.

[0017] System 100 is an electronic system having brake-by-wire technology.

[0018] System 100 is operatively associated with vehicle 1.

[0019] More specifically, system 100 includes a slip control module 101.

[0020] Wheel slip means the behavior of a wheel due to the relative difference between the wheel speed and the vehicle speed.

[0021] The slip control module 101 is, for example, a hardware module or a software logic module within the braking system or more generally within the main hardware modules of vehicle 1.

[0022] System 100 further includes a plurality of actuator modules 102.

[0023] Each module of the plurality of actuator modules 102 includes a respective actuator control module and a respective actuator adapted to execute a braking command based on the control received from the respective actuator control module.

[0024] Each actuator control module is, for example, a hardware module or a software logic module in the braking system or more generally in the main hardware modules of vehicle 1.

[0025] Each actuator is either electro-mechanical or electro-hydraulic.

[0026] The slip control module 101 is configured to receive information MD representative of vehicle 1 and transmit one or more commands representative of a braking request BR to the plurality of actuator modules 102 based on such information MD.

[0027] In this specification, “Vehicle-Representative Information MD” means detected and / or estimated information from a vehicle, i.e., a detection device (real or virtual sensor) installed in a corner (front or rear of the vehicle), but not necessarily limited to the vehicle’s braking system.

[0028] Multiple actuator modules 102 are configured to apply one or more braking actions BA to the corners 110 of the vehicle 1 based on one or more commands representing a braking request BR received from the slip control module 101.

[0029] Please note that "braking action" refers to the braking force / torque applied by the actuator module on the corresponding wheel.

[0030] It is worth noting that, in addition to transmitting one or more braking request BR commands, the slip control module 101 is configured to provide control mode MC and configuration parameters CP, which will be described in more detail below, to multiple actuator modules 102.

[0031] Referring to Figure 2, the wheel slip control module 101 is configured to include a plurality of wheel slip control submodules 103.

[0032] The wheel slip control submodules of the multiple wheel slip control submodules 103 are configured to control each corner of the vehicle 1.

[0033] More specifically, if vehicle 1 has four wheels (two on the front axle and two on the rear axle), the multiple wheel slip control submodules 103 include the following:

[0034] The first wheel slip control submodule C-FL for the front left corner.

[0035] The second wheel slip control submodule C-FR for the front right corner.

[0036] The third wheel slip control submodule C-RL for the rear left corner.

[0037] The fourth wheel slip control submodule (C-RR) for the rear right corner.

[0038] Referring again to Figure 2, the multiple actuator control modules 102 are located at the corners of the vehicle 1.

[0039] More specifically, again, if vehicle 1 has four wheels (two on the front axle and two on the rear axle), the multiple actuator control modules 102 include the following:

[0040] Front left corner's first actuator control module A-FL.

[0041] The second actuator control module A-FR for the front right corner.

[0042] The third actuator control module A-RL at the rear left corner.

[0043] The fourth actuator control module A-RR at the rear right corner.

[0044] One or more commands representing the braking request BR, transmitted from the slip control module 101 to the multiple actuator control modules 102, include the following:

[0045] The first wheel slip control submodule C-FL for the front left corner provides the first braking request BR1 to the first actuator control module A-FL for the front left corner.

[0046] A second braking request BR2 is provided to the second actuator control module A-FR of the front right corner by the second wheel slip control submodule C-FR of the front right corner.

[0047] A third braking request BR3 is provided to the third actuator control module A-RL of the rear left corner by the third wheel slip control submodule C-RL of the rear left corner.

[0048] The fourth braking request BR4 is provided to the fourth actuator control module A-RR for the rear right corner by the fourth wheel slip control submodule C-RR for the rear right corner.

[0049] It is worth noting that each wheel slip module is configured to transmit its respective braking request BR1, BR2, BR3, or BR4, as well as to provide control modes MC-1, MC-2, MC-3, or MC-4 and configuration parameters CP-1, CP-2, CP3, or CP-4, which will be described in more detail below, to multiple actuator modules 102.

[0050] The one or more braking actions BA that the multiple actuator modules 102 can perform on the vehicle 1 include the following:

[0051] The first braking action BA1 is provided to the front left wheel W-FL of vehicle 1 by the first actuator control module A-FL of the front left corner.

[0052] A second braking action BA2 is provided to the front right wheel W-FR of vehicle 1 by the second actuator control module A-FR of the front right corner.

[0053] A third braking action BA3 is applied to the rear left wheel W-RL of vehicle 1 by the third actuator control module A-RL of the rear left corner.

[0054] A fourth braking action BA4 is provided to the rear right wheel W-RR of vehicle 1 by the fourth actuator control module A-RR of the rear right corner.

[0055] In Figure 2, note that vehicle 1 further includes a chassis CS to which a front axle consisting of a front left wheel W-FL and a front right wheel W-FR and a rear axle consisting of a rear left wheel W-RL and a rear right wheel W-RR are movably connected.

[0056] Furthermore, as again schematically shown in Figure 2, the vehicle 1 is configured to include a braking request module 111 which is configured to issue a braking request to the vehicle 1.

[0057] A braking request that the braking request module 111 can issue is one of the items of vehicle-representative information MD provided to the control module 100.

[0058] In the embodiment shown in Figure 2, the braking request module 111 is configured to include a brake pedal BP adapted to allow the driver of vehicle 1 to issue a braking request to vehicle 1.

[0059] In this embodiment, the braking request means the position and / or pressure of the brake pedal.

[0060] In combination with alternative or prior art, according to further embodiments shown by dashed lines in Figure 2, the braking request module 111 has one or more control logics BC configured to issue a braking request, such as automated vehicle driving assistance logic, e.g., of the Autonomous Emergency Braking (AEB) type, or automated autonomous driving logic.

[0061] According to various embodiments schematically shown in Figures 3a, 3b, and 3c, the system 100 can be configured from a software standpoint based on the distribution of one or more electronic control units in the vehicle 1.

[0062] One or more electronic control units have several tasks, one of which is to implement the slip control module 101.

[0063] It is worth noting that a single electronic control unit can be configured to implement up to N wheel slip control submodules.

[0064] In the case of a vehicle with N corners and a single electronic control unit configured to implement all N wheel slip control submodules, the system 100 is named centralized.

[0065] Instead, in the case of a vehicle having N corners and N electronic control units, each configured to implement a single wheel slip submodule, the system 100 is named distributed.

[0066] This modularity of the system 100 according to these embodiments increases the flexibility of the system 100 itself for various distribution configurations of one or more electronic control units in the vehicle 1.

[0067] According to the embodiment shown in Figure 3A, the system 100, in particular, a plurality of wheel slip control submodules 103 distributed at single corners C-1, C-2, ..., CN of the vehicle 1, can be configured to coordinately control a number of vehicle corners that is less than or equal to the total number of corners of the vehicle 1.

[0068] In this configuration, also known as the fully decentralized (BbW decentralized - full) system, the distribution of electronic control units and wheel slip control submodules is based on the corners of vehicle 1.

[0069] Such a configuration may, in an embodiment, provide an electronic control unit for each corner and a wheel slip control submodule for each control unit associated with the relevant corner.

[0070] For example, referring to Figure 3A, corner C-1 may be the front left corner to which the first wheel slip control submodule C-FL corresponds.

[0071] According to further embodiments adapted to provide greater flexibility, an electronic control unit may be configured to implement multiple corner wheel slip control submodules, while other electronic control units may not be configured to implement any wheel slip control submodules.

[0072] According to a further embodiment shown in Figure 3B, the system 100, in particular, a plurality of wheel slip control submodules 103 arranged on a single axle A-1, A-2, ..., AN of the vehicle 1, may be configured to coordinately control a number of axles that is less than or equal to the total number of axles of the vehicle 1.

[0073] In this configuration, also known as the BbW decentralized-partial system, the distribution of electronic control units and wheel slip control submodules is based on the axles of vehicle 1.

[0074] In an embodiment, this configuration may provide an electronic control unit for each axle and a wheel slip control submodule for each control unit related to the corner associated with the axle.

[0075] For example, referring to Figure 3B, the single axle A-1 may be the front axle and may include a first wheel slip control submodule C-FL and a second wheel slip control submodule C-FR.

[0076] According to further embodiments adapted to offer greater flexibility, the electronic control unit may be configured to implement multiple wheel slip control submodules for the axle.

[0077] According to a further embodiment shown in Figure 3C, the system 100, in particular the slip control module 101 when the latter is centralized, can be configured to coordinately control a number of corners of vehicle 1 that is less than or equal to the total number of corners of vehicle 1.

[0078] In this configuration, also known as the BbW centralized system, there is a single electronic control unit that includes multiple wheel slip control submodules 103 for a single corner C-1, C-2, ..., CN of vehicle 1.

[0079] The slip control module 101 will now be explained in more detail with reference to Figures 4A to 4G.

[0080] From a software perspective, note that each wheel slip control submodule of the wheel slip control module 101, and therefore each of the multiple wheel slip control modules 103, is configured to perform a method for controlling wheel slip in the vehicle's braking system, as described below.

[0081] The slip control module 101 is comprised of an input interface module 40.

[0082] For example, the input interface module 40 is a hardware module or software logic module in the brake system or, more generally, in the main hardware module of the vehicle 1.

[0083] The input interface module 40 is configured to receive input information MD, which represents the vehicle 1 as described earlier with reference to Figures 1 and 2, and information MS, which represents the estimation of the vehicle's state.

[0084] Information MD representing vehicle 1 is provided by components of vehicle 1, such as sensors and / or a CAN (Controller Area Network) network and / or one or more electronic control units at one corner of the vehicle.

[0085] In this regard, as shown in Figure 4A, the vehicle-representing information MD has one or more of the following information groups.

[0086] A first group of information, MD-1, detectable by the sensors installed in vehicle 1.

[0087] A second set of information, MD-2, detectable by the CAN network or other data communication channels of vehicle 1.

[0088] A third information group MD-3 detectable by one or more electronic control units in a single vehicle corner.

[0089] It should be noted that this third information group, MD-3, further includes information that can be detected at vehicle corners other than those involving the slip control module 101.

[0090] Instead, the information MS representing the estimated state of the vehicle is provided by the vehicle state estimation module MSV (shown only in Figure 6).

[0091] For example, the vehicle state estimation module (MSV) is a hardware module or software logic module within the brake system or, more generally, the main hardware module of vehicle 1.

[0092] In this embodiment, the module MSV may be located inside the system 100.

[0093] According to a further embodiment replacing the preceding one, the module MSV may be located outside of system 100.

[0094] Returning to the input interface module 40, it is configured to output input wheel slip control information SCD, which is provided as input to further modules of the slip control module 101 located downstream of the input interface module 40.

[0095] The input wheel slip control information SCD is essential information for controlling wheel slip by the wheel slip control module 101, and is selected by the interface module 40 from information MD representing vehicle 1 and information MS representing the state of the vehicle.

[0096] More specifically, the input wheel slip control information SCD includes at least the following:

[0097] Wheel speed (detectable by sensors mounted on the vehicle).

[0098] Vehicle longitudinal acceleration (detectable by sensors mounted on the vehicle).

[0099] Lateral acceleration of the vehicle (detectable by sensors mounted on the vehicle).

[0100] Yaw rate (detected by sensors mounted on the vehicle).

[0101]

[0111] Vehicle speed (provided by the vehicle state estimation module).

[0102] Wheel slip (provided by the vehicle condition estimation module).

[0103] Road surface grip (provided by the vehicle condition estimation module).

[0104] Wheel acceleration (provided by the vehicle state estimation module).

[0105] Side slip angle (provided by the vehicle status estimation module).

[0106] Side wheel slippage (provided by the vehicle condition estimation module).

[0107] Identification of the vehicle driver type (provided by the vehicle status estimation module).

[0108] Status information for other vehicle corners (SlipControlEnable, SCE, and SP-V setpoint values ​​of the control variables applied to the vehicle corners, as described later).

[0109] Referring again to Figure 4A, the input interface module 40 includes a parameter self-loading module 41.

[0110] For example, the parameter self-loading module 41 is a software module or software logic module within the brake system or, more generally, the main hardware module of the vehicle 1.

[0111] The parameter self-loading module 41 is configured to determine the wheel slip control parameter SCP, which is used by the control logic of the wheel slip control module 101, based on information MD representing the vehicle 1 and information MS representing the state of the vehicle 1.

[0112] The wheel slip control parameter SCP is a parameter used in formulas / laws to control further modules of the wheel slip control module 101 located downstream of the input interface module 40, and is described below with reference to Figures 4b-4g.

[0113] Some examples of these parameters are the controller's gain and time constant, the slip setpoint table, and the trigger threshold of the aforementioned module.

[0114] An example of the decision is shown in the following section, in terms of loading the parameter set as a function of road grip.

[0115] The wheel slip control parameter SCP may be divided into discrete subsets, or it may be determined as the output of an interpolation function based on information MD representing vehicle 1 and information MS representing the state of vehicle 1.

[0116] According to one embodiment, the wheel slip control parameter SCP is relative to various road grips ("high grip", "medium grip", "low grip") and may be divided into various subsets according to the estimated road grip received from the vehicle state estimation module, and the parameter self-loading module 41 is configured to load the corresponding subsets of the wheel slip control parameter SCP.

[0117] According to a further embodiment replacing the previous one, the parameter self-loading module 41 is configured to determine the wheel slip control parameter SCP as a function of the estimated road grip received from the vehicle state estimation module 1, for example.

[0118] The parameter SCP = default parameter SCP × function (default grip / estimated grip), where parameter SCP is the default parameter SCP × function (default grip / estimated grip).

[0119] Default Parameter SCP: The relevant / calibrated parameter for default grip (e.g., a specific gain for the wheel slip control module).

[0120] function = interpolation logic to adapt the parameter to the estimated grip (for example, linear interpolation logic. Parameter SCP = default parameter SCP × (default grip / estimated grip)).

[0121] Default grip: High grip, dry asphalt, μ=1.

[0122] Referring to Figure 4B, the wheel slip control module 101 further includes a plurality of wheel slip control enablement modules 42.

[0123] For example, each of the multiple wheel slip control enablement modules 42 is a software module or software logic within the brake system or, more generally, the main hardware module of the vehicle 1.

[0124] The multiple wheel slip control enable modules 42 consist of at least one wheel slip control enable module for each corner of the vehicle.

[0125] For example, referring to Figure 4B, the multiple wheel slip control enable modules 42 include the following:

[0126] The first enable module E-FL for front left corner wheel slip control.

[0127] The second enable module for wheel slip control in the front right corner (E-FR).

[0128] Third enable module E-RL for rear left corner wheel slip control.

[0129] The fourth enable module E-RR for rear right corner wheel slip control.

[0130] Multiple wheel slip control enable modules 42 are configured to generate multiple wheel slip control enable signals SCE based on the received input wheel slip control information SCD and the received wheel slip control parameter SCP.

[0131] More specifically, each of the multiple wheel slip control enable modules 42 is configured to determine the respective enable signal of the multiple wheel slip control enable signals SCE based on the received input wheel slip control information SCD and the received wheel slip control parameter SCP.

[0132] It should be noted that the wheel slip control enable module 42 is configured to enable wheel slip control when an imminent loss of wheel stability and / or vehicle stability is detected.

[0133] For example, the wheel slip control activation module 42 is configured to detect an imminent loss of wheel stability by evaluating a wheel slip estimation assessment (WheelSlip) and comparing such assessment with a function threshold of the vehicle state (SlipThreshold[f(vehicle speed, road grip, brake pedal speed, wheel acceleration)]), and thus enable (true) wheel slip control for one or more corners of the vehicle.

[0134] If WheelSlip >= SlipThreshold [f(vehicle speed, road grip, brake pedal speed)], then SlipControlEnable (SCE) = True.

[0135] According to a further embodiment illustrated in Figure 4C, in combination with the preceding, the slip control module 101 further comprises a plurality of wheel slip setpoint definition modules 43.

[0136] For example, each of the multiple wheel slip set point definition modules 43 is a software module or software logic within the main hardware module of the brake system or, more generally, the vehicle 1.

[0137] The multiple wheel slip set point definition modules 43 consist of at least one wheel slip set point definition module for each corner of the vehicle.

[0138] Referring to Figure 4C, the multiple wheel slip setpoint definition modules 43 include the following:

[0139] The first definition module D-FL for the first wheel slip setpoint for the front left corner.

[0140] The second definition module D-FR for the second wheel slip setpoint for the front right corner.

[0141] Third definition module D-RL for the third wheel slip set point for the rear left corner.

[0142] The fourth definition module D-RR for the fourth wheel slip set point for the rear right corner.

[0143] Multiple wheel slip setpoint definition modules 43 are configured to generate wheel slip setpoints SP-S based on the received input wheel slip control information SCD and the received wheel slip control parameters SCP.

[0144] In the embodiment, the slip set point is a reference slip set point with a constant value name defined by the parameter self-loading module 41 of the input interface module 40.

[0145] In a further embodiment, in combination with the preceding, the slip setpoint is determined by each definition module as a function of information MS representing the state of the vehicle, starting from each reference slip setpoint.

[0146] Multiple wheel slip set point definition modules 43 are configured to modulate a reference wheel slip set point in real time to obtain the optimal wheel slip set point for advantageously maximizing the vehicle's dynamic performance during braking, for each single corner of the vehicle, based on the received input wheel slip control information SCD and the received wheel slip control parameter SCP.

[0147] For example, the wheel slip setpoint can be modulated as a function of road grip and vehicle lateral acceleration, starting from a reference wheel slip setpoint.

[0148] Slipsetpoint = SlipSetpoint reference * f(load grip, lateral acceleration).

[0149] Referring to Figure 4D, the slip control module 101 further includes a plurality of closed-loop wheel slip control modules 44.

[0150] For example, each of the multiple closed-loop wheel slip control modules 44 is a software module or software logic within the brake system or, more generally, the main hardware module of the vehicle 1.

[0151] The multiple wheel slip closed-loop control modules 44 consist of at least one closed-loop wheel slip control module for each corner of the vehicle.

[0152] Referring to Figure 4D, the multiple closed-loop wheel slip control modules 44 include the following:

[0153] First closed-loop wheel slip control module CL-1 for front left corners.

[0154] Second closed-loop wheel slip control module CL-2 for front right corners.

[0155] Third closed-loop wheel slip control module CL-3 for rear left corners.

[0156] Fourth closed-loop wheel slip control module CL-4 for rear right corners.

[0157] Each closed-loop wheel slip control module, including software adjustment logic (e.g., PID control, acronym for Proportional-Integral-Derivative), is configured to determine the set point SP-V of the control variables to be applied to each vehicle corner based on a defined slip set point SP-S and an estimated wheel slip value during each software execution cycle, and to minimize the error between the defined slip set point SP-S and the estimated wheel slip.

[0158] Examples of control variables include force or position or electrical voltage or pressure or torque or electrical current that can be exerted through each actuator at the vehicle corner.

[0159] In the embodiment, in combination with the above, each closed-loop wheel slip control module consists of software logic for initializing or resetting the control logic based on discrete events (exceeding control activation and / or error thresholds, as well as event-driven logic for reducing or increasing the required force) in order to favorably accelerate control fluctuations in the face of rapid changes in operating conditions.

[0160]

[0170] According to a further embodiment combined with the one in progress, graphically shown in Figure 4E, the slip control module 101 further comprises a plurality of reference target correction modules 45.

[0161] "Reference target" refers to the setpoint value SP-V of the control variable applied to each vehicle corner, as determined by the closed-loop wheel slip control module described above.

[0162] For example, each of the multiple reference target correction modules 45 is a software module or software logic within the main hardware module of the brake system or, more generally, the vehicle 1.

[0163] The multiple reference target correction modules 45 include at least one reference target correction module for each corner of the vehicle.

[0164] Referring to Figure 4E, the multiple target correction modules 45 include the following:

[0165] First reference target correction module CT-1 for the front left corner.

[0166] Second reference target correction module CT-2 for the front right corner.

[0167] Third reference target correction module CT-3 for the rear left corner.

[0168] The CT-4 is a fourth reference target correction module for the rear right corner.

[0169] Multiple reference target correction modules 45 are configured to correct (overwrite and / or reduce) the reference target value received as input by providing a corrected reference target value TC as output based on discrete events (exceeding a slip threshold and / or exceeding a wheel acceleration threshold and / or a single corner open-loop control request).

[0170] It should be noted that the multiple reference target value correction modules 45 are configured to correct the reference target value by implementing nonlinear fluctuations.

[0171] Nonlinear fluctuations in the control variable can, for example, reduce the force value in the presence of high wheel acceleration (WheelAcc), thereby increasing the responsiveness of the control given by rapid changes in the control variable.

[0172] If WheelAcc >= WheelAccThreshold [f(vehicle speed, road grip, ...)] then ForceTarget = ForceTarget - ForceCompensation).

[0173] WheelAcc = Wheel acceleration (from input wheel slip control information SCD).

[0174] WheelAccThreshold = The acceleration threshold at which compensation is performed.

[0175] ForceTargetOut = Force TC (corrected reference target value) output from multiple reference target correction modules 45.

[0176] ForceTargetIn = Force SP_V (setpoint value) input to multiple reference target correction modules 45.

[0177] ForceCompensation = Force compensation value (included in the wheel slip control parameter SCP).

[0178] Referring here to Figure 4F, in combination with the preceding, the slip control module 101 further comprises multiple adjustment modules 46 for the force FC defined for each axle corner.

[0179] For example, each force adjustment module defined for the corner of one of the multiple vehicle axles is a software module or software logic within the braking system or, more generally, the main hardware module of vehicle 1.

[0180] The multiple adjustment modules 46 consist of at least one force adjustment module defined for each corner of the vehicle, for each corner of the vehicle, for each individual vehicle axle corner.

[0181] Referring to Figure 4F, the multiple adjustment modules 46 for the forces defined for each vehicle axle corner include the following:

[0182] A first adjustment module FA-S of forces defined for front axle corners, specifically an adjustment module adapted to provide a first slip control force FC-1 for the front left corner of the vehicle and a second slip control force FC-2 for the front right corner of the vehicle.

[0183] A second adjustment module RA-S for forces defined for rear axle corners, the second adjustment module adapted to provide a third slip control force FC-3 for the rear left corner of the vehicle and a fourth slip control force FC-4 for the rear right corner of the vehicle.

[0184] Multiple adjustment modules 46 are configured to determine saturation for the maximum and / or minimum force that may be required for a single corner of each axle by evaluating the vehicle's grip, vertical load, stability, and speed conditions based on a setpoint value TC (reference target value) of the control variables provided by the preceding module.

[0185] This limitation allows for the adjustment and optimization of the logic defined for each corner / side of the vehicle to ensure the overall stability of the vehicle.

[0186] For example, if there are different road grips on both sides of the vehicle, the high-grip side can be restricted using the following logic, depending on the road grip and vehicle speed.

[0187] The force saturation on the high-grip side = the required force on the low-grip side + a force value defined by a mathematical function that takes vehicle information as input.

[0188] According to a further embodiment illustrated in Figure 4G, the slip control module 101 further comprises a plurality of configuration interface modules 47 of the actuator control module, which are present in each of the plurality of actuator modules 102.

[0189] For example, each of the multiple configuration interface modules 47 is a software module or software logic within the main hardware module of the brake system or, more generally, the vehicle 1.

[0190] The multiple configuration interface modules 47 consist of at least one configuration interface module for an actuator control module for each corner of the vehicle.

[0191] For example, referring to Figure 4G, the multiple configuration interface modules 47 include the following:

[0192] The first configuration interface module CNF-1 of the actuator control module for the front left corner.

[0193] The second configuration interface module CNF-2 of the front right corner actuator control module.

[0194] The third configuration interface module CNF-3 of the rear left corner actuator control module.

[0195] The fourth configuration interface module CNF-4 of the rear right corner actuator control module.

[0196] Each of the multiple configuration interface modules 47 is configured to define the control (logic) mode MC of the actuator control module for each vehicle corner.

[0197] Furthermore, each of the multiple interface configuration modules 47 is configured to define a set of configuration parameters CP provided for loading into the actuator control module of the relevant corner of the vehicle.

[0198] As shown in Figure 4G,

[0199] The first configuration interface module CNF-1 is configured to define a first control mode MC-1 for the front left corner actuator control module and a first set of configuration parameters CP-1 provided for loading to the front left corner actuator control module.

[0200] The second interface module CNF-2 is configured to define a second control mode MC-2 for the front right corner actuator control module and a second set of configuration parameters CP-2 provided for loading to the front right corner actuator control module.

[0201] The third interface module CNF-3 is configured to define a third control mode MC-3 for the rear left corner actuator control module and a third set of configuration parameters CP-3 provided for loading to the rear left corner actuator control module.

[0202] The fourth interface module CNF-4 is configured to define a fourth control mode MC-4 for the rear right corner actuator control module and a fourth set of configuration parameters CP-4 provided for loading to the rear right corner actuator control module.

[0203] More specifically, each of the multiple configuration interface modules 47 is configured to define the most suitable configuration for the actuator control module of each corner of the vehicle, in terms of the control (logic) mode MC and the configuration parameter set CP provided for the load, based on the received input wheel slip control information SCD (such as single corner information). Based on the wheel slip control parameter SCP, and based on information MS representing the state of the vehicle (vehicle speed, steering type, road type, vehicle instability state), the setpoint values ​​SP-V of the control variables (see Figure 4D) (e.g., the force to be applied to each vehicle corner) are determined, based on the state of the individual wheels (slip and / or high acceleration, tire / road grip state), etc.

[0204] The control (logic) mode MC represents a different control mode that can be activated to control the actuator.

[0205] A particular control mode is distinguished from others by the type of control module and / or control architecture (e.g., position control or actuator force control).

[0206] The configuration parameter set is used for a specific control mode MC to be activated.

[0207] For example, in the presence of activation of the high-grip slip control mode MC, the configuration interface module implements, as the control mode MC, a closed-loop force control mode for maximizing the modulation speed, and specific configuration parameters as the configuration parameter set CP for controlling the expected high-grip force.

[0208] Next, with reference to the aforementioned figures and the block chart in Figure 5A, a method 500 for controlling wheel slip in a vehicle brake system according to the present invention will be described.

[0209] The components and information described later, along with the explanation of the method, have already been explained earlier with reference to System 100, and therefore, for the sake of brevity, they will not be repeated.

[0210] Method 500 includes symbolic steps to initiate ST.

[0211] Method 500 includes step 501 of receiving information MD representing the vehicle 1 and information MS representing an estimate of the vehicle's state through the input interface module 40 of the slip control module 101.

[0212] Method 500 further includes step 502 of outputting input wheel slip control information SCD via the input interface module 40.

[0213] Method 500 further comprises step 503, in which a parameter self-loading module 41 of the input interface module 40 determines a wheel slip control parameter SCP based on information MD representing the vehicle 1 and information MS representing the state of the vehicle 1.

[0214] According to the embodiment, the wheel slip control parameter SCP is related to different road grips ("high grip", "medium grip", "low grip") and can be divided into various subsets as a function of the estimated road grip received from the vehicle state estimation module.

[0215] In this embodiment, the determination step 503 includes a step 504 in which the parameter self-loading module 41 of the input interface module 40 loads a corresponding subset of the wheel slip control parameters SCP.

[0216] According to a further embodiment replacing the previous one, the determination step 503 is performed to determine the wheel slip control parameter SCP as a function of the estimated road grip received from the Estimation Module MSV of the State of Vehicle 1 by the parameter self-loading module 41 of the input interface module 40.

[0217] Looking at Figure 5 in general terms, method 500 further includes step 505, in which multiple wheel slip control enablement modules 42 of slip control module 101 determine multiple wheel slip control enablement signals SCE based on the received input wheel slip control information SCD and the received wheel slip control parameters SCP.

[0218] Method 500 further comprises step 506, which determines a setpoint value SP-V of a control variable applied to each vehicle corner based on a defined slip setpoint SP-S and an estimated wheel slip value, using each closed-loop wheel slip control module 44 of the slip control module 101, thereby minimizing the error between the defined slip setpoint SP-S and the estimated wheel slip.

[0219] Method 500 includes a symbolic step that terminates the ED.

[0220] According to one embodiment (shown by a dashed line in Figure 5), in combination with any one of the preceding, method 500 has the following steps after the determination step 506.

[0221] Step 507 defines the control (logic) mode MC of the actuator control module for the relevant corner of the vehicle 1 by each of the multiple interface configuration modules 44 of the actuator control module present in each of the multiple actuator modules 102.

[0222] Step 508 defines a set of configuration parameters CP to be provided to load the actuator control module of the relevant corner of the vehicle 1, which is presented to each actuator module of the multiple actuator modules 102 by each interface configuration module 44.

[0223] In the embodiment, in combination with any one of the preceding (shown by a dashed line in Figure 5), method 500 comprises a step 509 between determining step 505 and determining step 506 in which a plurality of wheel slip set point definition modules 43 of the slip control module 101 generate a slip set point SP-S based on the received input wheel slip control information SCD and the received wheel slip control parameter SCP.

[0224] In the embodiment (shown by dashed lines in Figure 5), in combination with the above, the generation step 509 comprises a step 510 in which a constant slip set point value is provided as a reference slip set point by the parameter self-loading module 41 of the input interface module 40.

[0225] In further embodiments (shown again by dashed lines in Figure 5), in combination with the preceding, the step of generating 509 further includes a step 511 in which each definition module determines a slip set point starting from each reference slip set point as a function of information MS representing the state of vehicle 1.

[0226] According to a further embodiment (shown by dashed lines in Figure 5), in combination with one of the above, method 500 further comprises a step 512 between the determining step 506 and the defining step 507 in which each wheel slip control module corrects each reference target value received at input based on discrete events (exceeding the wheel slip threshold and / or exceeding the wheel acceleration threshold, and requiring open-loop control of a single corner) by a plurality of reference target correction modules 45, and then outputs a corrected reference target value TC.

[0227] In a further embodiment (shown by dashed lines in Figure 5), in combination with the preceding, method 500 further comprises a step 513 between the step defining 512 and the step defining 507, in which conditions such as vehicle grip, vertical load, stability and speed are evaluated by a plurality of adjustment modules 46 of the force FC defined for a single axle corner of the vehicle based on setpoint values ​​of control variables, and a saturation is defined with respect to the maximum and / or minimum force that can be requested for a single axle corner.

[0228] Next, an example of the operation of the slip control module 101 will be described with reference to Figure 6.

[0229] The input interface module 40 is configured to receive, as input, information MD representing vehicle 1 as previously described with reference to Figures 1 and 2, and information MS representing the estimated value of the vehicle state provided by the vehicle state estimation module MSV.

[0230] The input interface module 40 outputs the input wheel slip control information SCD and, via the parameter self-loading module 41, determines the wheel slip control parameter SCP based on the information MD representing the vehicle 1 and the information MS representing the state of the vehicle 1.

[0231] The first slip control enable module E-FL generates the first wheel slip control enable signal SCE for the front left corner based on the received wheel slip control parameter SCP and the input wheel slip control information SCD.

[0232] The first wheel slip setpoint definition module D-FL for the front left corner generates a first wheel slip setpoint SP-S based on the received wheel slip control parameter SCP and the received input wheel slip control information SCD.

[0233] The first closed-loop wheel slip control module CL-1 of the front left corner, after receiving the first enable signal SCE, determines, for each software execution cycle, a setpoint value SP-V of the control variable to be applied to each vehicle corner, based on the defined slip setpoint SP-S and the estimated wheel slip value, in order to minimize the error between the defined slip setpoint SP-S and the estimated wheel slip.

[0234] The first reference target correction module CT-1 for the front left corner, upon receiving the first enable signal SCE, corrects (overwrites and / or reduces) the reference target value received as input by providing a corrected reference target value TC as output, based on discrete events (excess of slip threshold and / or wheel acceleration threshold and / or open-loop control request for single corner).

[0235] The first force adjustment module FA-S, defined for front axle cornering, provides a first slip control force F1 for the front left corner of the vehicle.

[0236] The first configuration interface module CNF-1 of the front left corner actuator control module defines a first control mode MC-1 of the front left corner actuator control module and a first set of configuration parameters CP-1 provided for loading into the first front left corner actuator control module A-FL to apply a first brake action BA1 to the front left wheel W-FL of vehicle 1.

[0237] It is noteworthy that the objective of this invention is fully achieved.

[0238] The present invention relates to a brake-by-wire architecture in which a method for controlling wheel slippage in a vehicle brake system and each system has the potential to constitute a single vehicle corner control mode as a function of wheel and / or vehicle state evaluation determined by a control and monitoring algorithm.

[0239] This method and each control system define a control system for vehicle braking logic, logic related to corner / wheel control, and logic related to actuator control in one or more control units, and can manage wheel slip in a specific optimized manner for a brake-by-wire system where BbW actuators are provided at each corner.

[0240] Furthermore, the methods and respective control systems of the present invention define control modes in which the wheel slip control module configures the single corner actuator control module according to the state of the wheel and / or vehicle, and selects an optimal configuration and parameter set for optimization prioritizing control responsiveness and performance over braking comfort.

[0241] Furthermore, the methods and control systems of the present invention possess modularity and flexibility that allows for adjustments between corners of the vehicle, thereby changing the vehicle category.

[0242] Furthermore, the methods and systems of the present invention can continuously adapt control logic based on the measurement and estimation of vehicle distribution signals, with more comprehensive architectural configurations and information / estimation / evaluation regarding vehicle distribution.

[0243] Furthermore, the methods and respective control systems of the present invention guarantee the following:

[0244]

[0254] Continuous modulation of wheel slip control.

[0245] Calibrating control logic is simpler because it is based on physical laws, allowing the use of theoretical calibration to support empirical / experimental methods instead of typical empirical / experimental methodologies.

[0246] The control mode / actuator control parameters are adapted as a function of the control logic of the wheel slip control module for each vehicle corner.

[0247] Those skilled in the art can modify and adapt the above-described methods and respective system embodiments without departing from the scope of protection of the appended claims, or replace them with other functionally equivalent elements to meet incidental needs. All features described above as belonging to one possible embodiment can be carried out independently of other described embodiments.

Claims

1. A method (500) for controlling wheel slip in the brake system of a vehicle (1), Step (501) of receiving information (MD) representing the vehicle (1) and information (MS) representing the estimation of the state of the vehicle (1) via the input interface module (40) of the slip control module (101), The input interface module (40) outputs input wheel slip control information (SCD) (502), Step (503) of determining wheel slip control parameters (SCP) based on the information (MD) representing the vehicle (1) and the information (MS) representing the state of the vehicle (1) using the parameter self-loading module (41) of the input interface module (40), The slip control module (101) has multiple wheel slip control activation modules (42) that determine a plurality of wheel slip control activation signals (SCE) based on the received input wheel slip control information (SCD) and the received wheel slip control parameters (SCP), in step (505). Step (506) of determining the setpoint value (SP-V) of the control variable to be applied to each vehicle corner in order to minimize the error between the defined slip setpoint (SP-S) and the estimated wheel slip value, based on the defined slip setpoint (SP-S) and the estimated wheel slip value, by each closed-loop wheel slip control module (44) of the slip control module (101), Step (507) defines the control mode (MC) of the actuator control module of the vehicle (1) by each interface configuration module (47) of the actuator control module present in each actuator module of the multiple actuator modules (102), A method (500) comprising the step (508) of defining a set of configuration parameters (CPs) to be provided for loading into the actuator control module of the relevant corner of the vehicle (1) by each interface configuration module (47) of the actuator control module present in each of the plurality of actuator modules (102).

2. The method (500) according to claim 1, wherein between the determining step (505) and the determining step (506), a step (509) is added in which a plurality of wheel slip set point definition modules (43) of the slip control module (101) generate the slip set point (SP-S) based on the received input wheel slip control information (SCD) and the received wheel slip control parameters (SCP).

3. The method according to claim 2 (500), wherein the generating step (509) includes the step (510) of providing a constant slip set point value as a reference slip set point by the parameter self-loading module (41) of the input interface module (40).

4. The method according to claim 3 (500), further comprising the step (511) of determining a slip setpoint from the reference slip setpoint as a function of information (MS) that represents the estimation of the state of the vehicle (1) by each definition module.

5. The method according to any one of the prior claims (500) of claim 1 to 4, further comprising between the determining step (506) and the defining step (507) a step (512) in which a plurality of reference target correction modules (45) of the slip control module (101) correct each reference target value received at the input based on discrete events, and then outputting the correct reference target value (TC).

6. The method of claim 5 (500), further comprising between the correcting step (512) and the defining step (507), a step (513) of evaluating conditions such as grip, vertical load, stability and speed of the vehicle (1) by a plurality of modules (46) for adjusting the forces defined for a single corner of each axle of the vehicle (1) based on the setpoint values ​​of the control variables, and defining the saturation of the maximum and / or minimum forces that can be requested for the single corner of each axle.

7. The wheel slip control parameters (SCPs) are divided into different subsets related to different road grips, The method according to any one of claims 1 to 6 (500), wherein the determining step (503) is to include the step (504) of loading a corresponding subset of wheel slip control parameters (SCPs) by the parameter self-loading module (41) of the input interface module (40), according to the estimated road grip received from the MSV of the vehicle (1).

8. The method according to any one of claims 1 to 6 (500), wherein the determining step (503) is performed by the parameter self-loading module (41) of the input interface module (40) to determine the wheel slip control parameter (SCP) as a function of the estimated road grip received from the vehicle state estimation module (1).

9. A system (100) for controlling wheel slip in the brake system of a vehicle (1), Slip control module (101), A plurality of actuator modules (102), each of the plurality of actuator modules (102) comprising an actuator control module and an actuator adapted to execute a braking command based on the control received from the respective actuator control module, The slip control module (101) is configured to receive information (MD) representing the vehicle (1) and, based on the information (MD), to send one or more commands representing a braking request (BR) to the plurality of actuator modules (102). The slip control module (101) is configured to perform a method for controlling wheel slip in the brake system of the vehicle (1) according to any one of claims 1 to 8, the system (100).

10. The slip control module (101) comprises a plurality of wheel slip control submodules (103) distributed on a single corner (C-1, C-2, ..., C-N) of the vehicle (1), The system (100) according to claim 9, wherein the plurality of wheel slip control submodules (103) are configured to coordinately control a number of vehicle corners that is less than or equal to the total number of corners of the vehicle (1).

11. The slip control module (101) has a plurality of wheel slip control submodules (103) arranged on a single axle (A-1, A-2, ..., A-N) of the vehicle (1), The system (100) according to claim 9, characterized in that the plurality of wheel slip control submodules (103) can be configured to coordinately control a number of axles that is less than or equal to the total number of axles of the vehicle (1).

12. The slip control module (101) is centrally managed, The system (100) according to claim 9, wherein the slip control module (101) can be configured to coordinately control a number of corners that is less than the number of corners of the vehicle (1) or equal to the total number of corners of the vehicle (1).

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