Vehicle control method, device and equipment based on electromechanical brake system

Abstract

The application discloses a vehicle control method, device and equipment based on an electromechanical brake system, and the method comprises the following steps: in the case that the electromechanical brake system fails, determining a first demand brake force according to a brake pedal stroke; determining a target motor brake force of a driving motor and a target line control brake force of the electromechanical brake system according to the first demand brake force and a failure type of the electromechanical brake system; and performing brake control on the vehicle according to the target motor brake force and the target line control brake force. The technical scheme of the application only needs to install an electromechanical brake system in the vehicle, and through the coordinated control of the electromechanical brake system and the brake force of the distributed driving motor, the vehicle still has a certain brake force after the failure of the electromechanical brake system, the stable driving of the vehicle is ensured, the cost of the vehicle brake system is reduced, and the safety risk of the vehicle in the failure of the EMB system is reduced.

Description

Technical Field

[0001] This application belongs to the field of vehicle distributed drive control technology, and in particular relates to a vehicle control method, device and equipment based on an electromechanical braking system. Background Technology

[0002] Electro-Mechanical Brake (EMB) systems control the braking of a vehicle by sending electrical signals to a motor to clamp the brake disc during braking. This approach offers advantages such as fast response and precise braking force control, and is gradually becoming the future direction of braking solutions for electric vehicles.

[0003] In vehicles with distributed drive control, the braking system can be an EMB system, and the drive system can be a hub motor or a wheel-side motor. During operation, such vehicles may experience brake failure due to EMB system malfunction. To mitigate the safety risks in this situation, a dual braking system approach is commonly used, consisting of an electro-hydraulic braking system and an EMB system. Each wheel is connected to both an electro-hydraulic braking system and an EMB system; if one braking system fails, the other is activated.

[0004] While the above solution improves braking safety, the use of two braking systems increases the cost of the vehicle's braking system. Summary of the Invention

[0005] The embodiments of this application provide a vehicle control method, apparatus, and equipment based on an electromechanical braking system, which can not only reduce the cost of the vehicle braking system, but also reduce the safety risks of the vehicle when the EMB system fails.

[0006] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0007] According to a first aspect of the embodiments of this application, a vehicle control method based on an electromechanical braking system is provided, comprising:

[0008] In the event of a malfunction in the electromechanical braking system, the first required braking force is determined based on the brake pedal travel.

[0009] Based on the first required braking force and the fault type of the electromechanical braking system, determine the target electromechanical driving force of the drive motor and the target linear control force of the electromechanical braking system.

[0010] The vehicle is braked based on the target electric motor power and the target line control power.

[0011] In some embodiments of this application, based on the foregoing scheme, the drive motor includes a first motor, a second motor, a third motor, and a fourth motor, and the electromechanical braking system includes a first actuator, a second actuator, a third actuator, and a fourth actuator. The first motor corresponds one-to-one with the first actuator, the second motor with the second actuator, the third motor with the third actuator, and the fourth motor with the fourth actuator. The fault types include single-wheel fault, coaxial two-wheel fault, same-side two-wheel fault, cross-wheel fault, three-wheel fault, and four-wheel fault.

[0012] In some embodiments of this application, based on the foregoing scheme, determining the target electromechanical driving force of the drive motor and the target linear control force of the electromechanical braking system according to the first required braking force and the fault type of the electromechanical braking system includes:

[0013] In the case where the fault type is the single wheel fault, the real-time motor power of the first motor is obtained, wherein the first motor is the motor corresponding to the actuator that has the single wheel fault.

[0014] The second required braking force of the second actuator is determined based on the first required braking force, wherein the second actuator is an actuator coaxial with the actuator that has experienced a single wheel failure;

[0015] Obtain the first maximum motor power of the first motor and the maximum line control power of the second actuator;

[0016] When the first maximum motor power is greater than or equal to the maximum line control power, the second required braking force is taken as the target motor power of the first motor.

[0017] When the first maximum motor power is less than the maximum line control power, the real-time motor power is used as the target line control power of the second actuator.

[0018] In some embodiments of this application, based on the foregoing scheme, determining the target electromechanical driving force of the drive motor and the target linear control force of the electromechanical braking system according to the first required braking force and the fault type of the electromechanical braking system includes:

[0019] In the case where the fault type is the coaxial two-wheel fault, the first total required braking force of the first actuator and the second actuator is determined according to the first required braking force, wherein the first actuator and the second actuator are two coaxial actuators that have failed;

[0020] The smaller value between the maximum braking force of the first motor and the maximum braking force of the second motor is taken as the second maximum motor driving force.

[0021] If the second maximum motor power is greater than half of the first total required braking force, half of the first total required braking force shall be used as the target motor power of the first motor and the target motor power of the second motor.

[0022] If the second maximum motor power is less than or equal to half of the first total required braking force, the second maximum motor power shall be used as the target motor power of the first motor and the target motor power of the second motor.

[0023] In some embodiments of this application, based on the foregoing scheme, determining the target electromechanical driving force of the drive motor and the target linear control force of the electromechanical braking system according to the first required braking force and the fault type of the electromechanical braking system includes:

[0024] In the case where the fault type is a fault of two wheels on the same side, a fault of two crossed wheels, a fault of three wheels, or a fault of four wheels, the second total required braking force of the third actuator and the fourth actuator is determined based on the first required braking force, wherein the third actuator and the fourth actuator are arranged on the second shaft;

[0025] The third total demand braking force of the first actuator and the second actuator is determined based on the second total demand braking force, wherein the first actuator and the second actuator are disposed on the first axis;

[0026] Obtain the third maximum motor power of the motor corresponding to the faulty actuator;

[0027] Based on the third maximum motor power and the third total braking force demand, determine the target motor power of the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power of the actuator that has not malfunctioned.

[0028] Based on the third maximum motor power and the second total braking force demand, the target motor power of the motor corresponding to the actuator that has malfunctioned in the second shaft and the target linear control power of the actuator that has not malfunctioned are determined.

[0029] In some embodiments of this application, based on the foregoing scheme, determining the target motor power of the motor corresponding to the faulty actuator in the first shaft and the target linear control power of the actuator that has not failed, according to the third maximum motor power and the third total braking force demand, includes:

[0030] When the third maximum motor power is greater than half of the third total braking force, half of the third total braking force is used as the target motor power for the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power for the actuator that has not malfunctioned.

[0031] When the third maximum electric motor power is less than or equal to half of the third total required braking force, the third maximum electric motor power is used as the target electric motor power for the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power for the actuator that has not malfunctioned.

[0032] In some embodiments of this application, based on the foregoing scheme, determining the target motor power of the motor corresponding to the faulty actuator in the second shaft and the target linear control power of the actuator that has not failed, according to the third maximum motor power and the second total braking force demand, includes:

[0033] When the third maximum motor power is greater than half of the second total required braking force, half of the second total required braking force is used as the target motor power for the motor corresponding to the actuator that has malfunctioned in the second shaft and the target line control power for the actuator that has not malfunctioned.

[0034] If the third maximum motor power is less than or equal to half of the second total required braking force, the third maximum motor power shall be used as the target motor power for the motor corresponding to the actuator that has malfunctioned in the second shaft and the target line control power for the actuator that has not malfunctioned.

[0035] According to a second aspect of the embodiments of this application, a vehicle control device based on an electromechanical braking system is provided, comprising:

[0036] The demand braking force determination unit is used to determine the first demand braking force based on the brake pedal travel in the event of a failure in the electromechanical braking system.

[0037] The target braking force determination unit is used to determine the target electromechanical force of the drive motor and the target linear control force of the electromechanical braking system based on the first required braking force and the fault type of the electromechanical braking system.

[0038] The vehicle braking control unit is used to control the vehicle's braking based on the target electric motor power and the target line control power.

[0039] According to a third aspect of the embodiments of this application, a vehicle control device based on an electromechanical braking system is provided, including a processor and a memory, wherein the memory stores computer program instructions executable by the processor, and when the processor executes the computer program instructions, it implements the steps of the method described in any of the first aspects above.

[0040] According to a fourth aspect of the embodiments of this application, a computer-readable storage medium is provided, wherein computer program instructions are stored therein, and when executed by a processor, the computer program instructions cause the processor to perform the steps of the method as described in any of the first aspects above.

[0041] In this application, in the event of a failure in the electromechanical braking system (EMB), a first required braking force is determined based on the brake pedal travel; based on the first required braking force and the failure type of the EMB, a target electromechanical braking force for the drive motor and a target line control force for the EMB are determined; and the vehicle is braked based on the target electromechanical braking force and the target line control force. This technical solution only requires one EMB to be installed in the vehicle. Through the coordinated control of the braking force of the EMB and the distributed drive motor, the vehicle still possesses a certain braking force after the EMB fails, ensuring stable vehicle operation, reducing the cost of the vehicle braking system, and minimizing the safety risks associated with EMB system failures.

[0042] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0044] Figure 1 A flowchart illustrating a vehicle control method based on an electromechanical braking system in one embodiment is shown.

[0045] Figure 2 A detailed schematic diagram of step 102 in one embodiment is shown;

[0046] Figure 3 A detailed schematic diagram of step 102 in one embodiment is shown;

[0047] Figure 4A detailed schematic diagram of step 102 in one embodiment is shown;

[0048] Figure 5 A block diagram of a vehicle control device based on an electromechanical braking system is shown in one embodiment;

[0049] Figure 6 A schematic diagram of a vehicle control device based on an electromechanical braking system is shown in one embodiment. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0052] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0053] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0054] It should also be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such uses of these terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described.

[0055] To enable those skilled in the art to better understand this application, the application scenarios involved in this application will be briefly described first.

[0056] In distributed drive control vehicles, the braking system can employ an EMB system, and the drive system can utilize hub motors or wheel-side motors. During operation, such vehicles may experience brake failure due to EMB system malfunctions. If some EMB actuators in the vehicle's EMB system fail, when the driver applies the brakes suddenly, the wheels corresponding to the faulty actuators will lack braking force, while the wheels corresponding to the non-faulty actuators will have braking force. This imbalance in braking force between the left and right sides of the vehicle can lead to instability and skidding. This application's embodiment utilizes the reverse driving force of the drive motors (i.e., hub motors or wheel-side motors) to coordinate and control the braking force during EMB system failures. The vehicle only needs one braking system (i.e., an EMB system). Through coordinated control between the EMB system and the distributed drive motors, stable vehicle operation can still be ensured after an EMB system failure, achieving redundant control in case of brake-by-wire failure.

[0057] Figure 1 A flowchart illustrating a vehicle control method based on an electromechanical braking system in one embodiment is shown, as follows: Figure 1 As shown, a vehicle control method based on an electromechanical braking system is provided, which may include the following steps S101 to S103.

[0058] In step S101, in the event of a malfunction in the electromechanical braking system, the first required braking force is determined based on the brake pedal travel.

[0059] Understandably, when a vehicle equipped with four-wheel hub motors or wheel-side motors is in motion, if the driver presses the brake pedal, the vehicle controller can communicate with the EMB system to obtain information returned by the EMB system in order to determine whether there is an actuator malfunction in the EMB system.

[0060] In the implementation process, the drive motor may include a first motor, a second motor, a third motor, and a fourth motor, and the electromechanical braking system includes a first actuator, a second actuator, a third actuator, and a fourth actuator. The first motor corresponds one-to-one with the first actuator, the second motor with the second actuator, the third motor with the third actuator, and the fourth motor with the fourth actuator. When any one of the first actuator, the second actuator, the third actuator, and the fourth actuator fails, it can be determined that the EMB system has failed.

[0061] It is understandable that after the driver presses the brake pedal, the brake pedal travel can be obtained. Based on the brake pedal travel and the mapping relationship between the brake pedal travel and the braking force, the first required braking force corresponding to the brake pedal travel can be obtained by looking up a table. This first required braking force is the braking force required by the driver.

[0062] In step S102, the target electromechanical power of the drive motor and the target linear control power of the electromechanical braking system are determined based on the first required braking force and the fault type of the electromechanical braking system.

[0063] It is understandable that vehicles equipped with EMB systems may experience the following types of malfunctions during operation: single-wheel malfunction, malfunction of two wheels on the same axle, malfunction of two wheels on the same side, malfunction of two wheels crossing each other, malfunction of three wheels, and malfunction of four wheels.

[0064] Among them, single-wheel failure refers to the actuator corresponding to a single wheel malfunctioning; coaxial two-wheel failure refers to the actuator corresponding to two wheels on the same axle malfunctioning; same-side two-wheel failure refers to the actuator corresponding to two wheels on the same side malfunctioning; cross-wheel failure refers to the actuator corresponding to two crossed wheels malfunctioning; three-wheel failure refers to the actuator corresponding to any three wheels malfunctioning; and four-wheel failure refers to the actuator corresponding to all four wheels malfunctioning.

[0065] During implementation, the braking force required by the faulty wheel is provided by the negative torque of the wheel's motor, that is, by the motor power of the drive motor corresponding to the faulty wheel, while the braking force required by the normal wheel is provided by the line control power of the EMB actuator of the normal wheel.

[0066] If the fault type is a single-wheel fault, the motor power compensation is performed according to the control strategy for single-wheel faults; if the fault type is a coaxial fault, the motor power compensation is performed according to the control strategy for coaxial faults; if the fault type is a fault in two wheels on the same side, the motor power compensation is performed according to the control strategy for two wheels on the same side; if the fault type is a fault in two crossed wheels, the motor power compensation is performed according to the control strategy for two crossed wheels; if the fault type is a three-wheel fault, the motor power compensation is performed according to the control strategy for three-wheel faults; if the fault type is a four-wheel fault, the motor power compensation is performed according to the control strategy for four-wheel faults.

[0067] Figure 2 A detailed schematic diagram of step 102 in one embodiment is shown, which is a control strategy for a single-wheel failure, such as... Figure 2 As shown, step 102 may include the following steps:

[0068] Step 201: In the case of a single wheel failure, obtain the real-time motor power of the first motor, where the first motor is the motor corresponding to the actuator that has a single wheel failure.

[0069] Step 202: Determine the second demand braking force of the second actuator based on the first demand braking force, wherein the second actuator is an actuator coaxial with the actuator that has experienced a single wheel failure;

[0070] Step 203: Obtain the first maximum motor power of the first motor and the maximum line control power of the second actuator;

[0071] Step 204: If the first maximum motor power is greater than or equal to the maximum linear control power, the second required braking force is used as the target motor power of the first motor.

[0072] Step 205: If the first maximum motor power is less than the maximum line control power, the real-time motor power is used as the target line control power for the second actuator.

[0073] During implementation, the second braking force of the second actuator can be determined based on the first braking force requirement and the braking force allocation map.

[0074] For ease of description, the four wheels of the vehicle will be numbered A, B, C and D respectively, where A and B are on the same axle, C and D are on the same axle, and A and C are on the same side.

[0075] Assuming the actuator experiencing a single-wheel failure is the actuator on wheel A (i.e., the first actuator), when the driver depresses the brake pedal, the actuator on wheel B (i.e., the second actuator) will provide corresponding drive-by-wire power F based on the brake pedal travel. b1 (i.e., the second braking force), the motor of wheel A (i.e., the first motor) sends negative torque for braking, and its real-time motor force is F. a1 To maintain vehicle stability during braking, it is necessary to make F a1 =F b1 .

[0076] Since the real-time motoring power of the motor needs to be determined based on the motor torque map and the current state of charge of the battery, the real-time motoring power F provided by the first motor is... a1 It may be less than the line control power F provided by the second actuator. b1 When wheels A and B brake, a smaller braking force is needed for both wheels to maintain equal braking force on both sides, thus ensuring vehicle stability during braking.

[0077] Assume the first maximum electric motor power output that the first motor can provide is F. tmax1 The maximum linear control power that the second actuator can provide is F. emax When F tmax1 ≥F emaxAt that time, the magnitude of the target motor power of the first motor and the target line control power of the second actuator are determined by the second required braking force F of the second actuator. b1 For reference, at this time, the target motor power of the first motor and the target linear control power of the second actuator are both the second required braking force F. b1 When F tmax1 <F emax At that time, the magnitude of the target motor power of the first motor and the target line control power of the second actuator are determined by the real-time motor power F of the first motor. a1 For reference, at this time, the target motor power of the first motor and the target linear control power of the second actuator are both the real-time motor power F. a1 If the driver presses the brake pedal hard, the line control power of the second actuator is greater than the real-time motor power of the first motor. Then the vehicle controller requests the second actuator to reduce the braking torque so that the two braking forces are equal, in order to ensure the vehicle's braking stability.

[0078] Figure 3 A detailed schematic diagram of step 102 in one embodiment is shown. This embodiment is a control strategy for coaxial two-wheel failure, such as... Figure 3 As shown, step 102 may include the following steps:

[0079] Step 301: In the case of a fault type of two coaxial wheels, determine the first total required braking force of the first actuator and the second actuator based on the first required braking force, wherein the first actuator and the second actuator are two coaxial actuators that have failed.

[0080] Step 302: The smaller value between the maximum braking force of the first motor and the maximum braking force of the second motor is taken as the second maximum motor driving force.

[0081] Step 303: If the second maximum motor power is greater than half of the first total braking force, half of the first total braking force is used as the target motor power of the first motor and the target motor power of the second motor.

[0082] Step 304: If the second maximum motor power is less than or equal to half of the first total required braking force, the second maximum motor power is used as the target motor power of the first motor and the target motor power of the second motor.

[0083] Assume the actuators experiencing a coaxial wheel failure are the actuator on wheel A (i.e., the first actuator) and the actuator on wheel B (i.e., the second actuator). The required braking force for the failed axle is F1, and the required braking force for the normal axle is F1'. When the driver presses the brake pedal, the required braking force for the normal axle can be obtained as F1' based on the first required braking force and the braking force distribution map. Then, using the formula F1 = βF1', the required braking force for the failed axle is calculated as F1, which is the first total required braking force for both the first and second actuators, where β is the braking force distribution coefficient.

[0084] The required braking force F1 for the faulty shaft is provided by the negative torque of the motor on that shaft (i.e., the motor power of the first motor and the motor power of the second motor). The smaller of the maximum braking force of the first motor and the maximum braking force of the second motor is taken as the maximum negative torque (i.e., the second maximum motor power) that the motor can currently provide. tmax2 When the second maximum electric motor power F tmax2 When the braking force is less than or equal to half of the first total braking force F1, the second maximum electric motor braking force F is used. tmax2 Output. The target motor power F of the first motor. a2 The target electric motor power F of the second motor b2 It can be calculated using the following formula:

[0085]

[0086] Among them, F tmax2 F1 is the second largest electric motor power, while F1 is the first total demand braking force.

[0087] Figure 4 A detailed schematic diagram of step 102 in one embodiment is shown. This embodiment represents a control strategy for two-wheel failure on the same side, two-wheel failure across different wheels, three-wheel failure, or four-wheel failure, such as... Figure 4 As shown, step 102 may include the following steps:

[0088] Step 401: In the case of a fault type of two wheels on the same side, two wheels crossing, three wheels, or four wheels, determine the second total required braking force of the third actuator and the fourth actuator based on the first required braking force, wherein the third actuator and the fourth actuator are set on the second axle.

[0089] Step 402: Determine the third total braking force of the first actuator and the second actuator based on the second total braking force demand, wherein the first actuator and the second actuator are mounted on the first axis;

[0090] Step 403: Obtain the third maximum motor power of the motor corresponding to the malfunctioning actuator;

[0091] Step 404: Based on the third maximum motor power and the third total braking force demand, determine the target motor power of the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power of the actuator that has not malfunctioned.

[0092] Step 405: Based on the third maximum motor power and the second total braking force, determine the target motor power of the motor corresponding to the actuator that has malfunctioned in the second shaft and the target linear control power of the actuator that has not malfunctioned.

[0093] In some embodiments, when the third maximum motor power is greater than half of the third total braking force, half of the third total braking force is used as the target motor power for the motor corresponding to the actuator that has failed in the first shaft and the target line control power for the actuator that has not failed.

[0094] In some embodiments, when the third maximum motor power is less than or equal to half of the third total required braking force, the third maximum motor power is used as the target motor power for the motor corresponding to the actuator that has failed in the first shaft and the target line control power for the actuator that has not failed.

[0095] Assume the actuators experiencing two wheel failures on the same side are the actuator on wheel A (i.e., the first actuator) and the actuator on wheel C (i.e., the third actuator). The actuators that do not fail are the actuator on wheel B (i.e., the second actuator) and the actuator on wheel D (i.e., the fourth actuator). The axle containing wheels A and B is the first axle, and the axle containing wheels C and D is the second axle. The required braking force (i.e., the third total required braking force) for the first axle is F2, and the required braking force (i.e., the second total required braking force) for the second axle is F2'. When the driver presses the brake pedal, the second total required braking force F2' can be obtained based on the first required braking force and the braking force distribution map. Then, the third total required braking force F2 can be calculated using the formula F2 = βF2', where β is the braking force distribution coefficient.

[0096] The braking force required by the faulty wheel is provided by the negative torque of the wheel's motor (i.e., the motor's power). When the braking force required by the faulty wheel exceeds the maximum negative torque of the wheel's motor, the maximum negative torque is output. At this time, it is necessary to request the actuators of the non-faulty wheels on the same axle to also brake at this maximum negative torque, that is, to ensure that the left and right braking forces of the first axle are equal, and the left and right braking forces of the second axle are equal, so as to ensure the stability of the vehicle during braking.

[0097] Specifically, the target motor power F of the motor in wheel A (i.e., the first motor) a3 The target line control power F of the actuator of wheel B (i.e., the second actuator) b3 It can be calculated using the following formula:

[0098]

[0099] Among them, F tmax3 F2 is the third maximum motor power of the first motor, and F2 is the third total braking force required.

[0100] The target electric motor power F of the C-wheel motor (i.e., the third motor) c3 The target line control power F of the actuator of wheel D (i.e., the fourth actuator) d3 It can be calculated using the following formula:

[0101]

[0102] Among them, F tmax3’ F2' is the third maximum motor power of the third motor, and F2' is the second total demand braking force.

[0103] When the braking force of the second actuator is greater than or equal to the third maximum motor power F of the first motor tmax3 When the vehicle controller requests the second actuator to reduce the braking force; when the braking force of the fourth actuator is greater than or equal to the third maximum motor driving force F of the third motor. tmax3’ At that time, the vehicle controller requests the fourth actuator to reduce the braking force.

[0104] Assume the actuators experiencing cross-wheel failures are the actuators on wheel A (i.e., the first actuator) and wheel D (i.e., the fourth actuator), while the actuators on wheel B (i.e., the second actuator) and wheel C (i.e., the third actuator) are not experiencing failures. The axle containing wheels A and B is the first axle, and the axle containing wheels C and D is the second axle. The required braking force (i.e., the third total required braking force) for the first axle is F2, and the required braking force (i.e., the second total required braking force) for the second axle is F2'. When the driver depresses the brake pedal, the second total required braking force F2' can be obtained based on the first required braking force and the braking force distribution map. Then, the third total required braking force F2 can be calculated using the formula F2 = βF2', where β is the braking force distribution coefficient.

[0105] The braking force required by the faulty wheel is provided by the negative torque of the wheel's motor (i.e., the motor's power). When the braking force required by the faulty wheel exceeds the maximum negative torque of the wheel's motor, the maximum negative torque is output. At this time, it is necessary to request the actuators of the non-faulty wheels on the same axle to also brake at this maximum negative torque, that is, to ensure that the left and right braking forces of the first axle are equal, and the left and right braking forces of the second axle are equal, so as to ensure the stability of the vehicle during braking.

[0106] Specifically, the target motor power F of the motor in wheel A (i.e., the first motor) a4 The target line control power F of the actuator of wheel B (i.e., the second actuator) b4 It can be calculated using the following formula:

[0107]

[0108] Among them, F tmax4 F2 is the third maximum motor power of the first motor, and F2 is the third total braking force required.

[0109] The target line control power F of the actuator in wheel C (i.e., the third actuator) c4 The target electric motor power F of the D wheel motor (i.e., the fourth motor) d4 It can be calculated using the following formula:

[0110]

[0111] Among them, F tmax3’ F2' is the third maximum motor power of the fourth motor, and F2' is the second total demand braking force.

[0112] When the braking force of the second actuator is greater than or equal to the third maximum motor power F of the first motor tmax4 When the vehicle controller requests the second actuator to reduce the braking force; when the braking force of the third actuator is greater than or equal to the third maximum motor force F of the fourth motor. tmax4’ At that time, the vehicle controller requests the third actuator to reduce the braking force.

[0113] Assume the actuators experiencing three wheel malfunctions are the actuators on wheel A (i.e., the first actuator), wheel B (i.e., the second actuator), and wheel C (i.e., the third actuator). The actuator that did not malfunction is the actuator on wheel D (i.e., the fourth actuator). The axle containing wheels A and B is the first axle, and the axle containing wheels C and D is the second axle. The required braking force (i.e., the third total required braking force) for the first axle is F2, and the required braking force (i.e., the second total required braking force) for the second axle is F2'. When the driver presses the brake pedal, the second total required braking force F2' can be obtained based on the first required braking force and the braking force distribution map. Then, the third total required braking force F2 can be calculated using the formula F2 = βF2', where β is the braking force distribution coefficient.

[0114] The braking force required by the faulty wheel is provided by the negative torque of the wheel's motor (i.e., the motor's power). When the braking force required by the faulty wheel exceeds the maximum negative torque of the wheel's motor, the maximum negative torque is output. At this time, it is necessary to request the actuators of the non-faulty wheels on the same axle to also brake at this maximum negative torque, that is, to ensure that the left and right braking forces of the first axle are equal, and the left and right braking forces of the second axle are equal, so as to ensure the stability of the vehicle during braking.

[0115] Specifically, the target motor power F of the motor in wheel A (i.e., the first motor) a5The target electric motor power F of the B-wheel motor (i.e., the second motor) b5 It can be calculated using the following formula:

[0116]

[0117] Among them, F tmax5 F1 is the smaller of the maximum braking force of the first motor and the maximum braking force of the second motor, and F2 is the third total braking force required.

[0118] The target electric motor power F of the C-wheel motor (i.e., the third motor) c5 The target line control power F of the actuator of wheel D (i.e., the fourth actuator) d5 It can be calculated using the following formula:

[0119] Among them, F tmax5’ F2' is the third maximum motor power of the third motor, and F2' is the second total demand braking force.

[0120] Assume the actuators experiencing a four-wheel malfunction are the actuators on wheel A (i.e., the first actuator), wheel B (i.e., the second actuator), wheel C (i.e., the third actuator), and wheel D (i.e., the fourth actuator). The axle containing wheels A and B is the first axle, and the axle containing wheels C and D is the second axle. The required braking force (i.e., the third total required braking force) on the first axle is F2, and the required braking force (i.e., the second total required braking force) on the second axle is F2'. When the driver depresses the brake pedal, the second total required braking force F2' can be obtained based on the first required braking force and the braking force distribution map. Then, the third total required braking force F2 can be calculated using the formula F2 = βF2', where β is the braking force distribution coefficient.

[0121] Specifically, the target motor power F of the motor in wheel A (i.e., the first motor) a6 The target electric motor power F of the B-wheel motor (i.e., the second motor) b6 It can be calculated using the following formula:

[0122]

[0123] Among them, F tmax6 F1 is the smaller of the maximum braking force of the first motor and the maximum braking force of the second motor, and F2 is the third total braking force required.

[0124] The target electric motor power F of the C-wheel motor (i.e., the third motor) c6 The target electric motor power F of the D wheel motor (i.e., the fourth motor) d6 It can be calculated using the following formula:

[0125] Among them, F tmax6’ F2' is the smaller of the maximum braking force of the third motor and the maximum braking force of the fourth motor, and F2' is the second total braking force required.

[0126] Assuming the EMB brake-by-wire system is functioning correctly, when the driver presses the brake pedal, the vehicle's four-wheel hub motors or wheel-side motors do not participate in braking control, and the front and rear axles distribute braking force normally.

[0127] In step S103, braking control is performed on the vehicle based on the target electric motor power and the target line control power.

[0128] Understandably, after calculating the target motor power or the target line control power of the actuator corresponding to each wheel, the target motor power can be sent to the corresponding motor, and the target line control power can be sent to the corresponding actuator, so that the motor brakes according to the target motor power and the actuator brakes according to the target line control power.

[0129] This application fully leverages the advantages of distributed drive motors, utilizing the reverse drag torque characteristics of hub motors or wheel-side motors, and coordinates with EMB actuators to establish a reasonable control strategy. When the driver requests vehicle braking, if the EMB actuator experiences a single or multiple wheel failure and cannot perform normal braking, the motor of the faulty wheel is controlled to output the target motor power, while the EMB actuators of the normal wheels output the target linear control power. This ensures vehicle braking stability and reduces the driver's stress load during braking.

[0130] The following describes an embodiment of the apparatus described in this application, which can be used to execute the vehicle control method based on an electromechanical braking system described in the above embodiments of this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the vehicle control method based on an electromechanical braking system described above in this application.

[0131] See Figure 5 The diagram shows a block diagram of a vehicle control device based on an electromechanical braking system according to an embodiment of this application.

[0132] like Figure 5As shown in the embodiment of this application, a vehicle control device based on an electromechanical braking system includes: a demand braking force determination unit 501, a target braking force determination unit 502, and a vehicle braking control unit 503. The demand braking force determination unit 501 is used to determine a first demand braking force based on the brake pedal travel when the electromechanical braking system malfunctions. The target braking force determination unit 502 is used to determine the target motor braking force of the drive motor and the target line control force of the electromechanical braking system based on the first demand braking force and the malfunction type of the electromechanical braking system. The vehicle braking control unit 503 is used to perform braking control on the vehicle based on the target motor braking force and the target line control force.

[0133] In some embodiments of this application, based on the aforementioned scheme, the drive motor includes a first motor, a second motor, a third motor, and a fourth motor, and the electromechanical braking system includes a first actuator, a second actuator, a third actuator, and a fourth actuator. The first motor corresponds one-to-one with the first actuator, the second motor with the second actuator, the third motor with the third actuator, and the fourth motor with the fourth actuator. The fault types include single-wheel fault, coaxial two-wheel fault, same-side two-wheel fault, cross-wheel fault, three-wheel fault, and four-wheel fault.

[0134] In some embodiments of this application, based on the foregoing scheme, the target braking force determination unit 502 is further configured to: obtain the real-time motor braking force of the first motor when the fault type is a single-wheel fault, wherein the first motor is the motor corresponding to the actuator experiencing the single-wheel fault; determine the second required braking force of the second actuator based on the first required braking force, wherein the second actuator is the actuator coaxial with the actuator experiencing the single-wheel fault; obtain the first maximum motor braking force of the first motor and the maximum linear control force of the second actuator; if the first maximum motor braking force is greater than or equal to the maximum linear control force, use the second required braking force as the target motor braking force of the first motor; if the first maximum motor braking force is less than the maximum linear control force, use the real-time motor braking force as the target linear control force of the second actuator.

[0135] In some embodiments of this application, based on the aforementioned scheme, the target braking force determination unit 502 is further configured to, in the case of a coaxial two-wheel failure, determine the first total required braking force of the first actuator and the second actuator based on the first required braking force, wherein the first actuator and the second actuator are two coaxial actuators that have failed; take the smaller value between the maximum braking force of the first motor and the maximum braking force of the second motor as the second maximum motor power; if the second maximum motor power is greater than half of the first total required braking force, take half of the first total required braking force as the target motor power of the first motor and the target motor power of the second motor; if the second maximum motor power is less than or equal to half of the first total required braking force, take the second maximum motor power as the target motor power of the first motor and the target motor power of the second motor.

[0136] In some embodiments of this application, based on the aforementioned scheme, the target braking force determination unit 502 is further configured to: determine the second total required braking force of the third actuator and the fourth actuator based on the first required braking force, wherein the third actuator and the fourth actuator are disposed on the second shaft, and determine the third total required braking force of the first actuator and the second actuator based on the fourth required braking force, wherein the first actuator and the second actuator are disposed on the first shaft; obtain the third maximum motor power of the motor corresponding to the actuator that has failed; determine the target motor power of the motor corresponding to the actuator that has failed in the first shaft and the target line control power of the actuator that has not failed based on the third maximum motor power and the third total required braking force; and determine the target motor power of the motor corresponding to the actuator that has failed in the second shaft and the target line control power of the actuator that has not failed based on the third maximum motor power and the second total required braking force.

[0137] In some embodiments of this application, based on the foregoing scheme, the target braking force determination unit 502 is further configured to, when the third maximum motor braking force is greater than half of the third total required braking force, use half of the third total required braking force as the target motor braking force of the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control force of the actuator that has not malfunctioned; and when the third maximum motor braking force is less than or equal to half of the third total required braking force, use the third maximum motor braking force as the target motor braking force of the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control force of the actuator that has not malfunctioned.

[0138] In some embodiments of this application, based on the foregoing scheme, the target braking force determination unit 502 is further configured to, when the third maximum motor braking force is greater than half of the second total required braking force, use half of the second total required braking force as the target motor braking force of the motor corresponding to the actuator that has malfunctioned in the second shaft and the target line control force of the actuator that has not malfunctioned; and when the third maximum motor braking force is less than or equal to half of the second total required braking force, use the third maximum motor braking force as the target motor braking force of the motor corresponding to the actuator that has malfunctioned in the second shaft and the target line control force of the actuator that has not malfunctioned.

[0139] Based on the same inventive concept, this application also provides a vehicle control device based on an electromechanical braking system, see reference. Figure 6 The diagram shows a schematic of the structure of a vehicle control device based on an electromechanical braking system according to an embodiment of this application. The vehicle control device based on an electromechanical braking system includes one or more memories 604, one or more processors 602, and at least one computer program (computer program instruction) stored in the memory 604 and executable on the processor 602. When the processor 602 executes the computer program, it implements the method described above.

[0140] Among them, Figure 6 In this document, a bus architecture (represented by bus 600) is used. Bus 600 may include any number of interconnected buses and bridges, linking various circuits including one or more processors represented by processor 602 and memory represented by memory 604. Bus 600 may also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. Bus interface 605 provides an interface between bus 600 and receiver 601 and transmitter 603. Receiver 601 and transmitter 603 may be the same element, i.e., a transceiver, providing a unit for communicating with various other devices over a transmission medium. Processor 602 is responsible for managing bus 600 and general processing, while memory 604 can be used to store data used by processor 602 during operation.

[0141] Based on the same inventive concept, embodiments of this application provide a computer-readable storage medium storing computer program instructions, which, when executed by a processor, cause the processor to perform the steps of the method described above.

[0142] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and embodiments are within the scope and spirit of this application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Furthermore, the functional units may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit.

[0143] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0144] The units described as separate components may or may not be physically separate. Similarly, the components of the control device may or may not be physical units; they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0145] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing computer program instructions, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0146] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A vehicle control method based on an electromechanical braking system, characterized in that, The drive motor includes a first motor, a second motor, a third motor, and a fourth motor. The electromechanical braking system includes a first actuator, a second actuator, a third actuator, and a fourth actuator. The first motor corresponds one-to-one with the first actuator, the second motor with the second actuator, the third motor with the third actuator, and the fourth motor with the fourth actuator. Fault types include actuators experiencing two-wheel failure on the same side, two-wheel failure (crossed), three-wheel failure, and four-wheel failure. The method includes: In the event of a malfunction in the electromechanical braking system, the first required braking force is determined based on the brake pedal travel. Based on the first required braking force and the fault type of the electromechanical braking system, determine the target electromechanical driving force of the drive motor and the target linear control force of the electromechanical braking system. The vehicle is braked based on the target electric motor power and the target line control power. The step of determining the target electromechanical power of the drive motor and the target linear control power of the electromechanical braking system based on the first required braking force and the fault type of the electromechanical braking system includes: In the case where the fault type is a fault of two wheels on the same side, a fault of two crossed wheels, a fault of three wheels, or a fault of four wheels, the second total required braking force of the third actuator and the fourth actuator is determined based on the first required braking force, wherein the third actuator and the fourth actuator are arranged on the second shaft; The third total demand braking force of the first actuator and the second actuator is determined based on the second total demand braking force, wherein the first actuator and the second actuator are disposed on the first axis; Obtain the third maximum motor power of the motor corresponding to the faulty actuator; Based on the third maximum motor power and the third total braking force demand, determine the target motor power of the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power of the actuator that has not malfunctioned. Based on the third maximum motor power and the second total braking force demand, the target motor power of the motor corresponding to the actuator that has malfunctioned in the second shaft and the target linear control power of the actuator that has not malfunctioned are determined.

2. The method according to claim 1, characterized in that, The fault types also include single-wheel failure and coaxial two-wheel failure of the actuator.

3. The method according to claim 2, characterized in that, The step of determining the target electromechanical power of the drive motor and the target linear control power of the electromechanical braking system based on the first required braking force and the fault type of the electromechanical braking system includes: In the case where the fault type is the single wheel fault, the real-time motor power of the first motor is obtained, wherein the first motor is the motor corresponding to the actuator that has the single wheel fault. The second required braking force of the second actuator is determined based on the first required braking force, wherein the second actuator is an actuator coaxial with the actuator that has experienced a single wheel failure; Obtain the first maximum motor power of the first motor and the maximum line control power of the second actuator; When the first maximum motor power is greater than or equal to the maximum line control power, the second required braking force is taken as the target motor power of the first motor. When the first maximum motor power is less than the maximum line control power, the real-time motor power is used as the target line control power of the second actuator.

4. The method according to claim 2, characterized in that, The step of determining the target electromechanical power of the drive motor and the target linear control power of the electromechanical braking system based on the first required braking force and the fault type of the electromechanical braking system includes: In the case where the fault type is the coaxial two-wheel fault, the first total required braking force of the first actuator and the second actuator is determined according to the first required braking force, wherein the first actuator and the second actuator are two coaxial actuators that have failed; The smaller value between the maximum braking force of the first motor and the maximum braking force of the second motor is taken as the second maximum motor driving force. If the second maximum motor power is greater than half of the first total required braking force, half of the first total required braking force shall be used as the target motor power of the first motor and the target motor power of the second motor. If the second maximum motor power is less than or equal to half of the first total required braking force, the second maximum motor power shall be used as the target motor power of the first motor and the target motor power of the second motor.

5. The method according to claim 1, characterized in that, The step of determining the target motor power of the motor corresponding to the faulty actuator in the first shaft and the target linear control power of the actuator that has not malfunctioned, based on the third maximum motor power and the third total braking force demand, includes: When the third maximum motor power is greater than half of the third total braking force, half of the third total braking force is used as the target motor power for the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power for the actuator that has not malfunctioned. When the third maximum electric motor power is less than or equal to half of the third total required braking force, the third maximum electric motor power is used as the target electric motor power for the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power for the actuator that has not malfunctioned.

6. The method according to claim 1, characterized in that, The step of determining the target motor power of the motor corresponding to the faulty actuator in the second shaft and the target linear control power of the actuator that has not malfunctioned, based on the third maximum motor power and the second total braking force demand, includes: When the third maximum motor power is greater than half of the second total required braking force, half of the second total required braking force is used as the target motor power for the motor corresponding to the actuator that has malfunctioned in the second shaft and the target line control power for the actuator that has not malfunctioned. If the third maximum motor power is less than or equal to half of the second total required braking force, the third maximum motor power shall be used as the target motor power for the motor corresponding to the actuator that has malfunctioned in the second shaft and the target line control power for the actuator that has not malfunctioned.

7. A vehicle control device based on an electromechanical braking system, characterized in that, The drive motor includes a first motor, a second motor, a third motor, and a fourth motor. The electromechanical braking system includes a first actuator, a second actuator, a third actuator, and a fourth actuator. The first motor corresponds one-to-one with the first actuator, the second motor with the second actuator, the third motor with the third actuator, and the fourth motor with the fourth actuator. Fault types include actuators experiencing two-wheel failure on the same side, two-wheel failure (crossed), three-wheel failure, and four-wheel failure. The device includes: The demand braking force determination unit is used to determine the first demand braking force based on the brake pedal travel in the event of a failure in the electromechanical braking system. The target braking force determination unit is used to determine the target electromechanical force of the drive motor and the target linear control force of the electromechanical braking system based on the first required braking force and the fault type of the electromechanical braking system. The vehicle braking control unit is used to perform braking control on the vehicle based on the target electric motor power and the target line control power; The target braking force determination unit is further configured to determine the second total required braking force of the third actuator and the fourth actuator based on the first required braking force when the fault type is the same-side two-wheel fault, the cross-wheel fault, the three-wheel fault or the four-wheel fault, wherein the third actuator and the fourth actuator are disposed on the second shaft; The third total demand braking force of the first actuator and the second actuator is determined based on the second total demand braking force, wherein the first actuator and the second actuator are disposed on the first axis; Obtain the third maximum motor power of the motor corresponding to the faulty actuator; Based on the third maximum motor power and the third total braking force demand, determine the target motor power of the motor corresponding to the actuator that has malfunctioned in the first shaft and the target line control power of the actuator that has not malfunctioned. Based on the third maximum motor power and the second total braking force demand, the target motor power of the motor corresponding to the actuator that has malfunctioned in the second shaft and the target linear control power of the actuator that has not malfunctioned are determined.

8. A vehicle control device based on an electromechanical braking system, comprising a processor and a memory, characterized in that, The memory stores computer program instructions that can be executed by the processor, and when the processor executes the computer program instructions, it implements the steps of the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions that, when executed by a processor, cause the processor to perform the steps of the method as described in any one of claims 1 to 6.

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