An electromechanical brake system and control strategy thereof

Abstract

An electromechanical brake system and its control strategy, comprising a brake signal acquisition unit, a clamping force acquisition unit, an electronic control module and an electromechanical brake execution module; when the electromechanical brake system acquires first and second brake signals, it works in a pressure building phase and a following phase respectively, and when no brake signal is acquired, it works in an elimination phase. In the pressure building phase, the brake caliper is in contact with the brake disc, in the following phase, the brake caliper applies brake clamping force to the brake disc for vehicle braking, and in the elimination phase, the brake caliper is separated from the brake disc. Since the electromechanical brake system is set to work in the pressure building phase within a preset brake pedal stroke depth range, the brake gap is preferentially eliminated; a brake gap wear self-adjusting strategy based on software detection can identify and compensate the change of the brake gap between the brake caliper and the brake disc, thereby enabling the brake response of the electromechanical brake system to be faster, more reliable and safer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile brake control, in particular to an electronic mechanical brake system and a control strategy thereof. BACKGROUND

[0002] With the continuous development of automobile electrification and intelligence and the gradual popularization of advanced auxiliary driving systems, further requirements are put forward for the functions and performances of automobile brake control systems. On the one hand, it is hoped that the brake control system can realize decoupling between pedal force and wheel braking force, ensure good pedal feeling, realize brake energy recovery, achieve high-precision and rapid brake response speed, and realize independent adjustment of automobile four-wheel braking force. On the other hand, it is hoped that the brake control system has the function of active braking to meet the needs of intelligent auxiliary driving systems such as emergency braking. Since the electronic mechanical brake system (EMB) is completely controlled by electrical signals, it can well meet the above requirements.

[0003] The EMB realizes the application and release of braking force by directly driving the brake with an electric motor. Generally, a position sensor (brake pedal sensor) is arranged on the brake pedal of the vehicle to obtain a brake control signal for an electronic control unit (ECU), and then the ECU controls the brake of the electronic mechanical brake system. In the prior art, the control strategy of the electronic mechanical brake system is based on the identification of the motor stall time and the PID-based motor control strategy, and the identification of the brake gap wear, the acquisition of the clamping force and other disturbance factors are not considered. Therefore, it is necessary to further improve the brake control strategy of the electronic mechanical brake system. SUMMARY

[0004] The electronic mechanical brake system and control strategy proposed in the embodiments of the present application have a suitable application range covering passenger vehicles and heavy commercial vehicles, and the proposed control strategy is beneficial to improving the safety and reliability of the electronic mechanical brake system.

[0005] According to a first aspect, an embodiment provides an electronic mechanical brake system for applying the electronic mechanical brake control strategy as described in the first aspect, the electronic mechanical brake system comprising an electronic control module; the electronic control module comprises:

[0006] a brake signal acquisition unit configured to acquire a stroke depth signal of a brake pedal or a brake instruction signal issued by a pre-set automatic emergency brake system;

[0007] a clamping force acquisition unit configured to calculate a brake clamping force for braking the vehicle according to the stroke depth signal or the brake instruction signal;

[0008] The brake driving unit is used to switch the working state of the electromechanical brake system according to the stroke depth signal, the brake instruction signal or the brake clamping force.

[0009] In an embodiment, the electromechanical brake system further comprises a mechanical execution module.

[0010] The mechanical execution module comprises a brake driver, a brake execution mechanism and a disc brake.

[0011] The brake driver comprises a brake driving motor, a motor output shaft and a motor controller assembly.

[0012] The brake driving motor is a double three-phase permanent magnet synchronous motor with two sets of three-phase windings.

[0013] The brake execution mechanism comprises a nut, a roller, a lead screw, a guide, a housing, a brake push rod, a front end cover, a brake lever, a hinge and a push disc.

[0014] The disc brake comprises a brake caliper and a brake disc.

[0015] In an embodiment, the brake driving motor is a double three-phase winding permanent magnet synchronous motor, which can reduce the motor working current, obtain higher output power and improve the motor fault tolerance capability.

[0016] In an embodiment, the output shaft of the brake driving motor is internally hollow, used to accommodate part of the lead screw, so as to reduce the overall axial length of the brake execution mechanism.

[0017] The nut is connected with the motor output shaft through a spline, and the axial position of the nut is fixed through a bearing, so that the nut rotates with the rotation of the motor output shaft.

[0018] The nut is internally provided with a threaded raceway, and the roller rolls in the threaded raceway, used to transmit the torque output by the brake driving motor to the lead screw via the nut and the roller, so as to make the lead screw move axially.

[0019] One end of the lead screw is provided with a hexagonal boss, and the axial displacement of the hexagonal boss in the hexagonal guide rail restricts the lead screw to only move axially.

[0020] The lead screw guide rail end is machined with a guide, and the translation of the lead screw is transmitted to the brake push rod via the guide, and the brake push rod is used to make the brake lever rotate around the fixed hinge by pushing the lever, so as to act on the brake caliper.

[0021] In one embodiment, a spring is provided on the housing of the brake push rod arrangement area to store energy when the brake caliper is in contact with the brake disc and to release energy during the elimination phase, so as to quickly separate the brake caliper from the brake disc and return it to its original position.

[0022] According to the electromechanical braking control strategy of the above embodiment, since the electromechanical braking system is set to work in the pressure build-up stage within a preset brake pedal travel depth range, the braking gap is eliminated first, making the braking efficiency of the electromechanical braking system faster, more reliable and safer.

[0023] According to a second aspect, one embodiment provides an electromechanical braking control strategy, including:

[0024] The operating states of an electromechanical braking system include the pressure build-up phase, the following phase, and the release phase.

[0025] During the pressure build-up phase, the brake caliper is brought into contact with the brake disc to eliminate the brake clearance of the disc brake in the electromechanical braking system; wherein, the disc brake includes the brake caliper and the brake disc;

[0026] During the following phase, a braking clamping force for vehicle braking is applied to the brake disc by the brake caliper;

[0027] During the elimination phase, the brake caliper is separated from the brake disc;

[0028] When the electromechanical braking system does not receive a braking signal, the electromechanical braking system operates in the elimination phase;

[0029] When the electromechanical braking system acquires the first braking signal, the electromechanical braking system operates in the pressure build-up phase;

[0030] When the electromechanical braking system acquires the second braking signal, the electromechanical braking system operates in the following phase;

[0031] The first braking signal and the second braking signal correspond to different travel depth ranges of the brake pedal, respectively.

[0032] In one embodiment, the electromechanical braking control strategy further includes:

[0033] Record the motor rotation angle after each execution of the pressure build-up phase;

[0034] The change in clearance due to brake wear is obtained based on the motor rotation angle at which the brake clearance is eliminated according to historical records.

[0035] When the gap value is greater than a preset gap threshold, wear compensation is performed on the braking gap based on the gap value.

[0036] In one embodiment, the electromechanical braking control strategy further includes:

[0037] The magnitude of the braking clamping force is related to the travel depth of the brake pedal and the wheel slip ratio; the braking clamping force is provided by the brake drive motor.

[0038] In one embodiment, the electromechanical braking control strategy further includes:

[0039] The driving current of the brake drive motor is positively correlated with the magnitude of the brake clamping force;

[0040] The electromechanical braking control strategy requires real-time monitoring of the drive current value of the braking drive motor.

[0041] The driving current of the brake drive motor is compensated based on the difference between the monitored driving current value and the expected driving current value of the brake drive motor, so as to correct or compensate for the braking clamping force.

[0042] According to a third aspect, one embodiment provides a computer-readable storage medium storing a program that can be executed by a processor to implement the electromechanical braking control strategy as described in the first aspect.

[0043] According to the fourth aspect, one embodiment provides a computer program product including a computer program and / or instructions that, when executed by a processor, implement the electromechanical braking control strategy as described in the first aspect. Attached Figure Description

[0044] Figure 1 This is a structural block diagram of an electromechanical braking system in one embodiment;

[0045] Figure 2 This is a schematic cross-sectional view of the mechanical structure of the mechanical execution module in one embodiment;

[0046] Figure 3 This is a schematic diagram of the external structure of the mechanical execution module in one embodiment;

[0047] Figure 4 This is a flowchart illustrating an electromechanical braking control strategy in one embodiment.

[0048] Figure 5 This is a schematic diagram of a software-compensated brake clearance wear process in one embodiment.

[0049] Figure label:

[0050] Brake drive motor 1; motor output shaft 2; motor controller assembly 3; nut 4; roller 5; lead screw 6; guide 7; housing 8; return spring 9; brake push rod 10; front end cover 11; brake lever 12; hinge 13; push plate 15; brake caliper 16; brake disc 17; electronic control module 100; brake signal acquisition unit 101; clamping force acquisition unit 102; brake drive unit 103; mechanical actuation module 200; brake driver 201; brake actuator 202; disc brake 203. Detailed Implementation

[0051] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0052] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0053] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0054] When a vehicle is operating in autonomous or intelligent assisted driving mode, the only ways to intervene in driving are through directional control and braking control. One method of braking intervention control is controlling the travel depth of the brake pedal. In existing technology, the brake pedal control mechanism works by having enough travel to engage the brake caliper with the brake disc, and then applying braking force to the disc. This braking force is directly proportional to the travel depth of the brake pedal. During the entire braking operation, for every braking action (pressing the brake pedal), the electromechanical braking system must first eliminate the brake gap in the disc brakes before applying braking force to the disc. This process of eliminating the brake gap prolongs the time required for braking. Another method of braking intervention control is through software settings (e.g., speed control according to a preset driving mode also requires acceleration and deceleration). The process of eliminating the brake gap also affects the accuracy of speed control.

[0055] In this embodiment, the electromechanical braking system's operating state includes three stages: a pressure-building stage, a following stage, and a pressure-eliminating stage. During the pressure-building stage, the brake caliper is pre-engaged with the brake disc (without further applying braking force to the disc), thus pre-eliminating the brake clearance of the disc brake and improving the timeliness and reliability of vehicle braking intervention control. Especially during defensive driving (after pressing the brake pedal), the driver can be subjectively informed whether the current pedal pressure and / or depth has pre-eliminated the brake clearance (i.e., whether the electromechanical braking system is currently operating in the pressure-building stage). Example

[0056] Please refer to Figure 1 This is a structural block diagram of an electromechanical braking system in one embodiment. The electromechanical braking system includes an electronic control module 100 and a mechanical execution module 200. The electronic control module 100 includes a brake signal acquisition unit 101, a clamping force acquisition unit 102, and a brake drive unit 103. The brake signal acquisition unit 101 is used to acquire a brake pedal travel depth signal or a brake command signal issued by a preset automatic emergency braking system. The clamping force acquisition unit 102 is used to calculate the braking clamping force for braking the vehicle based on the travel depth signal or the brake command signal. The brake drive unit 103 is used to switch the operating state of the electromechanical braking system based on the travel depth signal, the brake command signal, or the braking clamping force. The mechanical execution module 200 includes a brake actuator 201, a brake execution mechanism 202, and a disc brake 203.

[0057] Please refer to Figure 2 and Figure 3The figures show a cross-sectional view and an external view of the mechanical structure of the mechanical execution module in one embodiment. The brake actuator 201 includes a brake drive motor 1, a motor output shaft 2, and a motor controller assembly 3. The brake actuator 202 may include a nut 4, rollers 5, a lead screw 6, a guide 7, a housing 8, a brake push rod 10, a front end cover 11, a brake lever 12, a hinge 13, and a push plate 15. The dashed arrow on the brake lever 12 indicates the working stroke of the brake lever 12. The disc brake 203 includes a brake caliper 16 and a brake disc 17. The output shaft of the brake drive motor 1 is hollow inside to accommodate part of the lead screw 6. The nut 4 is connected to the motor output shaft 2, and its axial position is fixed by a bearing so that the nut 4 rotates with the rotation of the motor output shaft 2. The nut 4 has a threaded raceway inside, and the rollers 5 roll in the threaded raceway to transmit the torque output by the brake drive motor 1 to the lead screw 6 via the nut 4 and rollers 5, so that the lead screw 6 moves axially. One end of the lead screw 6 is provided with a hexagonal boss. The axial displacement of the lead screw 6 within the hexagonal guide rail by the hexagonal boss constrains the lead screw 6, allowing it to move only axially. A guide member 7 is machined at the guide rail end of the lead screw 6. The translation of the lead screw 6 is transmitted to the brake push rod 10 via the guide member 7. The brake push rod 10 is used to push the brake lever to rotate around the fixed hinge 13, thereby acting on the brake caliper 16. A return spring 9 is provided on the housing of the area where the brake push rod 10 is arranged. This spring stores energy when the brake caliper 16 is in contact with the brake disc 17 and releases energy when the electromechanical braking system is in the elimination phase, so as to quickly separate the brake caliper 16 from the brake disc 17 and return it to its original position.

[0058] The electromechanical braking system disclosed in one embodiment of this application employs a computer-controlled brake control motor and brake actuator to apply braking force to disc or drum brakes. Compared to traditional braking devices, the electronic control module replaces some mechanical and hydraulic components with electronic components and more compact mechanical devices, forming a mechatronic system. During vehicle braking, each controller collects vehicle status and external environmental information from wheel speed sensors, brake pedal position sensors, etc., and calculates the required braking clamping force for the brake disc based on its internal algorithm. The controller then controls the brake control motor to output corresponding torque based on the calculated desired braking clamping force, controlling the brake push rod to achieve braking. Compared to traditional pneumatic and hydraulic braking devices, the electronic control module offers faster braking response, higher safety, and a more compact structure. Furthermore, it can be better integrated with systems such as ABS and ESP, significantly improving vehicle reliability and stability.

[0059] exist Figure 2In the mechanical actuation module shown, the motor output shaft 2, connected to the brake drive motor 1, is internally machined to be hollow, which can accommodate part of the volume of the lead screw 6 to reduce the axial dimension of the electromechanical braking system. The motor output shaft 2 is connected to the nut 4, and the power of the motor is transmitted to the nut 4 through a spline, causing the nut 4 to rotate with the rotation of the motor output shaft 2. The axial position of the nut 4 is fixed by a bearing, constraining the nut 4 to prevent axial displacement and allowing only rotation about the axis. The nut 4 has a threaded raceway inside, allowing the rollers 5 to roll within the threaded raceway. The rotation of the nut 4 is transmitted to the lead screw 6 via the rollers 5, causing the lead screw 6 to move axially. One end of the lead screw 6 is housed in the motor output shaft 2, and the other end is machined with a hexagonal boss. On the one hand, this boss can constrain the rotational freedom of the lead screw 6 while allowing axial movement through the hexagonal internal channel of the housing 8, preventing the lead screw 6 from rotating about the axis; on the other hand, it increases the contact area between the lead screw 6 and the guide member 7, making the power of the lead screw 6 more smoothly transferred to the guide member 7. The connection process between the guide member 7 and the brake push rod 10 allows the guide member 7 to rotate at a small angle around the connection point, thereby reducing the axial force on the brake push rod 10 caused by the height difference between the connection end of the brake lever and the brake push rod 10 during the rotation of the brake lever around the hinge 13 during braking. A return spring 9 is provided on the front cover 11 (on the housing in the area where the brake push rod is arranged), which can store energy during braking and release energy during release for rapid return to its original position after braking ends.

[0060] After the brake lever is activated by the brake push rod 10, it rotates around the hinge 13, transmitting power to the push plate 15. This causes the push plate 15 to push the brake calipers 16 on both sides of the brake disc to move, thereby clamping the brake disc 17 to achieve braking.

[0061] In one embodiment, the brake drive motor of the electromechanical braking system is a dual three-phase winding permanent magnet synchronous motor. The presence of two sets of three-phase windings reduces the operating current of each phase winding, increases the motor's output power, and when a phase winding experiences an open-circuit fault, the brake drive motor can be fault-tolerantly controlled through the other set of three-phase windings, preserving complete or a certain degree of emergency braking function.

[0062] Please refer to Figure 4 This is a flowchart illustrating an electromechanical braking control strategy in one embodiment. Another embodiment of this application discloses an electromechanical braking control strategy applied to the electromechanical braking system described above, specifically including:

[0063] The electromechanical braking system operates in three phases: pressure build-up, follow-up, and release. During the pressure build-up phase, the brake caliper engages with the brake disc to eliminate the brake clearance of the disc brake in the electromechanical braking system. The disc brake includes a caliper and a brake disc. During the follow-up phase, the caliper applies a braking clamping force to the brake disc for vehicle braking. During the release phase, the caliper disengages from the brake disc. When the electromechanical braking system does not receive a braking signal, it operates in the release phase. When it receives a first braking signal, it operates in the pressure build-up phase. When it receives a second braking signal, it operates in the follow-up phase. The first and second braking signals correspond to different ranges of brake pedal travel.

[0064] In one embodiment, the electromechanical braking control strategy further includes:

[0065] First, the brake clamping force estimation algorithm estimates the brake clamping force of the electromechanical braking system in real time. Then, a suitable brake clamping force value is designed as the contact judgment threshold condition between the brake caliper and the brake disc, hereinafter referred to as the "contact threshold". When the estimated brake clamping force exceeds the contact threshold, the pressure build-up stage is considered to be completed, and the brake gap is considered to be eliminated.

[0066] Record the motor rotation angle through which the brake gap is eliminated after each execution of the pressure build-up phase. Then, obtain the gap value caused by brake wear based on the historical motor rotation angle for eliminating the brake gap. If the gap value is greater than a preset gap threshold, perform wear compensation on the brake gap based on the obtained gap value.

[0067] In one embodiment, the braking clamping force is provided by a brake drive motor. The magnitude of the braking clamping force is related to the brake pedal travel depth and the wheel slip ratio.

[0068] In one embodiment, the drive current of the brake drive motor is positively correlated with the magnitude of the brake clamping force, and the electromechanical braking control strategy further includes:

[0069] First, the drive current value of the brake drive motor is monitored in real time. Then, the drive current of the brake drive motor is compensated based on the difference between the monitored drive current value and the expected drive current value of the brake drive motor, so as to correct or compensate for the braking clamping force.

[0070] In one embodiment of this application, the electromechanical braking control strategy uses the braking clamping force as the control target and the braking clamping force calculated by the braking clamping force estimation algorithm as the feedback input to correct the actual tracking of the braking clamping force. The goal of the pressure-building phase (when the braking clamping force is zero) is to quickly eliminate the braking gap within the electromechanical braking system actuator and the brake. At this time, the braking clamping force is not used as a control input, and the maximum speed of the brake drive motor is set to the tracking target to achieve the purpose of quickly eliminating the braking gap. The goal of the braking clamping force following phase (when the braking clamping force is a preset expected value) is to accurately follow the expected braking clamping force input from the upper layer. At this time, the control target is switched from the expected speed to the expected braking clamping force, and all controllers operate normally. Building upon the brake clamping force build-up stage, this phase utilizes a slip ratio controller to assess the vehicle's actual braking condition based on braking parameters such as vehicle speed and slip ratio. It then outputs corresponding compensation current to further refine the brake clamping force control. Furthermore, a sliding mode observer monitors disturbances in the electromechanical braking system and unmodeled uncertainties during braking, calculating corresponding compensation currents which are input to the current controller to correct the brake clamping force. Additionally, a brake clamping force estimator calculates an estimated brake clamping force based on the actual rotation angle and output torque of the brake drive motor, using this estimate as input to the brake clamping force controller. This achieves closed-loop control of the brake clamping force, ultimately enabling precise tracking of the brake clamping force. The control objective of the elimination phase (restoring brake clearance) shifts to rapidly eliminating braking force and quickly returning the actuator to its original position, thereby reducing negative impacts such as energy loss and mechanical wear caused by untimely or incomplete brake disengagement. First, the control target is switched from the desired braking clamping force to the desired speed (the maximum reverse speed of the brake drive motor). At this time, the position controller, speed controller, and current controller are in operation, controlling the brake drive motor to track the target speed, thereby enabling the actuator to quickly return to its original position. Then, when the estimated braking clamping force is less than the contact threshold, the brake drive motor is switched to position closed-loop control, causing the brake caliper to completely separate from the brake disc and achieving the return of all braking mechanisms to their zero positions. Similarly, springs are installed on the brake push rod area housing and the brake lever area housing to store energy during the pressure build-up and following phases, and release energy during the decompression phase to enable the mechanism to quickly return to its original position.

[0071] In one embodiment, the switching logic from the normal driving phase to the pressure-building phase of the electromechanical braking system is designed based on the upper-level braking command or the driver's braking pedal input. When the upper-level inputs a braking command or the driver depresses the brake pedal (receiving the first braking signal), the braking clamping force pressure-building phase begins. This phase first uses the maximum speed of the brake drive motor as the tracking target to achieve rapid pressure building and generate braking force. Then, when the estimated braking clamping force exceeds the contact threshold, it is considered that the braking gap has been completely eliminated. At this point, the motor rotation angle remains unchanged, and the system waits for further braking commands.

[0072] In one embodiment, the switching logic from the pressure build-up phase to the following phase of the electromechanical braking system is designed based on the estimated clamping force. When the desired braking clamping force input from the upper layer is not zero (a second braking signal is acquired) and the estimated braking clamping force at the current moment exceeds the contact threshold, the system switches from the pressure build-up phase to the following phase, and realizes the switching of the control target from rotational speed to braking clamping force. The system controls the brake drive motor to output the corresponding braking torque to achieve tracking of the target braking clamping force.

[0073] In one embodiment, the switching logic from the brake clamping force following stage to the brake clamping force elimination stage is designed based on the input of the upper-level clamping force and the estimated value of the actual clamping force. When the expected brake clamping force input from the upper level is zero and the estimated clamping force is not zero, the system switches from the brake clamping force following stage to the brake clamping force elimination stage, and switches the control target from brake clamping force to speed, controlling the brake drive motor to reverse. When the estimated brake clamping force further decreases and is less than the contact threshold, the system switches from the speed control target to the position control target, enabling each mechanism to quickly return to its original position and the brake to completely separate.

[0074] In one embodiment, the switching logic from the elimination phase to the normal driving phase is designed based on the output speed of the brake drive motor. When there is no braking command input from the upper layer, the estimated clamping force is less than the contact threshold, and the speed of the brake drive motor is zero, it indicates that the mechanisms have completely separated, the braking process ends, and the vehicle returns to normal driving.

[0075] refer to Figure 5This is a schematic diagram illustrating the software compensation process for brake clearance wear in an electromechanical braking control strategy of one embodiment. Specifically, it includes: controlling the brake clearance through a clearance compensation controller. The clearance controller records the brake drive motor rotation angle at the moment each clearance is eliminated, and calculates the clearance value caused by brake wear based on the difference between the brake drive motor rotation angle at the moment the current clearance is eliminated and the theoretical brake drive motor rotation angle at the moment the clearance is eliminated. When the clearance value is less than a threshold, no compensation is performed; when the clearance value is greater than the threshold, the corresponding compensation angle is calculated, and the brake drive motor rotates through the corresponding compensation angle after the current braking ends and before the next braking, and the current motor rotor position is set to the initial position, thus achieving clearance compensation.

[0076] The electromechanical braking control strategy disclosed in this application includes: when the electromechanical braking system acquires a first braking signal and a second braking signal, the electromechanical braking system operates in a pressure-building phase and a following phase, respectively; when the electromechanical braking system does not acquire a braking signal, it operates in an elimination phase. Specifically, during the pressure-building phase, the brake caliper is in contact with the brake disc; during the following phase, the brake caliper applies a braking clamping force to the brake disc for vehicle braking; and during the elimination phase, the brake caliper is separated from the brake disc. Because the electromechanical braking system operates in the pressure-building phase within a preset brake pedal travel depth range, it prioritizes eliminating brake clearance, resulting in faster, more reliable, and safer braking efficiency.

[0077] Those skilled in the art will understand that all or part of the functions of the various methods in the above embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, which may include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to achieve the above functions. For example, the program can be stored in the memory of a device, and when the program in the memory is executed by the processor, all or part of the above functions can be achieved. In addition, when all or part of the functions in the above embodiments are implemented by computer programs, the program can also be stored in a server, another computer, disk, optical disk, flash drive, or external hard drive, etc., and can be downloaded or copied to the memory of a local device, or the system of the local device can be updated. When the program in the memory is executed by the processor, all or part of the functions in the above embodiments can be achieved.

[0078] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. An electromechanical braking control strategy, characterized in that, include: The operating states of an electromechanical braking system include the pressure build-up phase, the following phase, and the release phase. During the pressure build-up phase, the brake caliper is brought into contact with the brake disc to eliminate the brake clearance of the disc brake in the electromechanical braking system; wherein, the disc brake includes the brake caliper and the brake disc, and the braking clamping force is provided by a brake drive motor; During the following phase, a braking clamping force for vehicle braking is applied to the brake disc by the brake caliper; During the elimination phase, the brake caliper is separated from the brake disc; When the electromechanical braking system does not receive a braking signal, the electromechanical braking system operates in the elimination phase; When the electromechanical braking system acquires the first braking signal, the electromechanical braking system operates in the pressure build-up phase; When the electromechanical braking system acquires a second braking signal and the estimated braking clamping force at the current moment exceeds a preset contact threshold, the operating state of the electromechanical braking system switches from the pressure-building stage to the following stage, so as to realize the switch from speed control of the brake drive motor to control of the braking clamping force, and to track the braking clamping force of the preset target by tracking the braking torque output by the brake drive motor; wherein, the preset contact threshold is a braking clamping force value, which is used as a contact judgment threshold condition between the brake caliper and the brake disc, and when the estimated braking clamping force at the current moment exceeds the contact threshold, it is considered that the brake gap has been eliminated; When the second braking signal acquired by the electromechanical braking system disappears and the current braking clamping force is not zero, the working state of the electromechanical braking system switches from the following stage to the elimination stage, so as to switch from controlling the braking clamping force of the brake drive motor to speed control and control the brake drive motor to reverse; when the braking clamping force further decreases and is less than the contact threshold, the speed control of the brake drive motor switches to position control, so that each mechanism of the electromechanical braking system quickly returns to its position, and the brake caliper and the brake disc are completely separated; The first braking signal and the second braking signal respectively correspond to different travel depth ranges of the brake pedal; Record the motor rotation angle at which the braking gap is eliminated after each execution of the pressure build-up phase; The gap value caused by brake wear is obtained based on the historical changes in the motor rotation angle that eliminates the brake gap. When the gap value is greater than a preset gap threshold, wear compensation is performed on the braking gap based on the gap value; The magnitude of the braking clamping force is related to the depth of the brake pedal travel, the wheel slip ratio, and / or the wheel speed; The driving current of the brake drive motor is positively correlated with the magnitude of the brake clamping force; The braking drive unit monitors the drive current value of the braking drive motor in real time; The driving current of the brake drive motor is compensated based on the difference between the monitored driving current value and the expected driving current value of the brake drive motor, so as to correct or compensate for the braking clamping force.

2. A computer-readable storage medium, characterized in that, The medium stores a program that can be executed by a processor to implement the electromechanical braking control strategy as described in claim 1.

3. A computer program product, comprising a computer program and / or instructions, characterized in that, When the computer program and / or instructions are executed by the processor, they implement the electromechanical braking control strategy as described in claim 1.

4. An electromechanical braking system, characterized in that, For applying the electromechanical braking control strategy as described in claim 1, the electromechanical braking system includes an electronic control module; The electronic control module includes: The brake signal acquisition unit is used to acquire the travel depth signal of the brake pedal or the brake command signal issued by a preset automatic emergency braking system. The clamping force acquisition unit is used to calculate the braking clamping force for braking the vehicle based on the travel depth signal or the braking command signal. The braking drive unit is used to switch the working state of the electromechanical braking system according to the stroke depth signal, the braking command signal or the braking clamping force, and is equipped with a current sensor and an angle sensor to monitor the drive current and mechanical rotation angle of the braking drive motor in real time.

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