Hub motor and brake-by-wire fusion control method, device and system and vehicle

Abstract

The invention relates to a hub motor and brake-by-wire fusion control method, device and system and a vehicle, relates to the technical field of vehicles, and aims to reasonably distribute the braking force of a hub motor and the braking force of a brake-by-wire system in a high-electric-quantity state, improve the control precision of vehicle braking and improve the vehicle braking efficiency. Comprising the steps that under the condition that the charge state of a power battery is larger than or equal to a preset threshold value, motion state information and brake pedal stroke information of a vehicle are collected; calculating a target negative torque of a hub motor and a target brake pressure of a brake-by-wire system based on the motion state information of the vehicle and the brake pedal travel information; and based on the target negative torque and the target brake pressure, the hub motor and the brake-by-wire system are controlled respectively.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, specifically to a hub motor and a brake-by-wire fusion control method, device, system, and vehicle. Background Technology

[0002] With the widespread adoption of a combined braking system of electric motor energy recovery and brake-by-wire in the braking systems of new energy vehicles, energy can be recovered through the electric motor when the battery is not fully charged, while brake-by-wire supplements the braking force, balancing energy saving and braking performance. Braking technology needs to meet the needs of users in various usage scenarios and be more compatible with the characteristics of electric motor drive in new energy vehicles.

[0003] In traditional new energy vehicles, hub motors can achieve multiple drive modes, have higher control precision over the wheels, and are easier to implement regenerative braking based on hub motors. Brake-by-wire systems are vehicle braking technologies that rely on wiring harnesses to transmit braking commands. They are divided into two categories: Electro-Hydraulic Brake (EHB) and Electro-Mechanical Brake (EMB), which are electronic braking schemes that transmit braking commands using electrical signals.

[0004] However, even when fully charged, there is still a problem with the braking force of each wheel not being precise enough. Summary of the Invention

[0005] This invention provides a hub motor and brake-by-wire fusion control method, device, system, and vehicle, aiming to rationally allocate the power of the hub motor and the braking force of the brake-by-wire system even under high battery conditions, thereby improving the control accuracy of vehicle braking.

[0006] In a first aspect, this application provides a fusion control method for a hub motor and a brake-by-wire system, comprising: acquiring vehicle motion state information and brake pedal travel information when the state of charge of the power battery is greater than or equal to a preset threshold; calculating the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle motion state information and the brake pedal travel information; and controlling the hub motor and the brake-by-wire system respectively based on the target negative torque and the target braking pressure.

[0007] Based on the aforementioned technical means, when the state of charge of the power battery is greater than or equal to a preset threshold, this application can obtain the current vehicle dynamics and the driver's braking intention by collecting the vehicle's motion state information and brake pedal travel information. Based on this, the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system are calculated, and the hub motor and the brake-by-wire system are controlled independently. This allows for a reasonable distribution of the power of the hub motor and the braking force of the brake-by-wire system even when the battery is at a high charge level, improving the control accuracy of vehicle braking, avoiding battery overcharging when the battery is at a high charge level, and optimizing the smoothness of the braking process while ensuring safety.

[0008] Furthermore, the road surface adhesion coefficient is calculated based on the vehicle's motion state information; the target total braking force desired by the driver is determined based on the brake pedal travel information; and the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system are calculated based on the vehicle's motion state information, the road surface adhesion coefficient, and the target total braking force.

[0009] Based on the aforementioned technical means, the current road surface adhesion coefficient is calculated in real time based on the vehicle's motion state information, avoiding excessive braking force or wheel lock-up tendencies caused by slippery road surfaces or sudden changes in adhesion, and providing road surface constraint boundaries for braking force distribution; simultaneously, the driver's desired total braking force is analyzed based on the brake pedal travel information, ensuring that the system response matches the driver's intention. Figure 1 Based on this, considering the overall motion state, adhesion limit, and total braking force requirements, the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system are calculated respectively. This allows for the coordinated distribution of electro-hydraulic braking forces without exceeding the road surface adhesion capacity, thereby improving the stability and energy utilization efficiency of the braking process.

[0010] Furthermore, a multi-objective optimization function is constructed based on the vehicle's motion state information, road surface adhesion coefficient, and target total braking force. The optimization objectives of the multi-objective optimization function include: minimizing the total braking force error, minimizing the negative torque fluctuation of the hub motor, and optimizing the vehicle's yaw stability. Solving the multi-objective optimization function yields the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0011] Based on the aforementioned technical methods, a multi-objective optimization function is constructed using vehicle motion state information, road surface adhesion coefficient, and target total braking force. Minimizing total braking force error, minimizing wheel hub motor negative torque fluctuation, and optimizing vehicle yaw stability are simultaneously used as optimization objectives. This allows for comprehensive consideration of braking accuracy, energy recovery smoothness, and vehicle attitude maintenance during the solution process. By solving this multi-objective optimization function, the target negative torque of the wheel hub motor and the target braking pressure of the brake-by-wire system can be obtained, enabling coordinated distribution of electric motor power and hydraulic braking force while meeting the total braking force requirements. Specifically, the optimization of the motor negative torque smoothness reduces torque abrupt changes during regenerative braking intervention, while the optimization of yaw stability maintains the vehicle's direction of travel through the rational distribution of braking force between the left and right wheels.

[0012] Furthermore, based on the constraints, a multi-objective optimization function is solved to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system. The constraints include at least one of the following: the target negative torque of the hub motor is less than or equal to the maximum negative torque of the motor when fully charged; the target braking pressure of the brake-by-wire system is less than or equal to the maximum pressure of the brake-by-wire system; and the target total braking force is less than or equal to the maximum friction force of the road surface.

[0013] Based on the aforementioned technical means, by assigning adjustable weight coefficients to each optimization objective in the multi-objective optimization function, the priority among total braking force accuracy, motor torque smoothness, and yaw stability can be dynamically adjusted according to different driving conditions or control requirements, making the control strategy flexible and adaptable to various scenarios. Among the introduced constraints, the target negative torque of the hub motor is limited to the maximum negative torque range under full-charge conditions, avoiding system shock or battery damage caused by forced regenerative braking due to the battery's inability to absorb energy; the target braking pressure of the brake-by-wire system is limited to its maximum pressure range, ensuring the feasibility of hydraulic braking commands; and the target total braking force is limited to within the maximum friction force of the road surface, preventing wheel lock-up or skidding due to braking force exceeding the road surface limits. The combined effect of these constraints ensures that the solution to the multi-objective optimization function always remains within the vehicle's braking capacity boundary and the road surface adhesion limit, guaranteeing the feasibility of the optimized target negative torque and target braking pressure at the practical execution level.

[0014] Furthermore, the multi-objective optimization function is transformed into a standard quadratic function; by solving the standard quadratic function, the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system are obtained.

[0015] Based on the aforementioned technical methods, by converting the multi-objective optimization function into a standard quadratic function, the mature solution efficiency and global convergence characteristics of quadratic programming algorithms can be utilized to enable complex allocation problems involving multiple optimization objectives and constraints to obtain optimal solutions within milliseconds. The target negative torque of the hub motor and the target braking pressure of the brake-by-wire system, directly output from the standard quadratic function, already implicitly incorporate the weighting coefficients and boundary constraints during the conversion process. Therefore, they can be used as direct control commands for the vehicle without additional adjustments.

[0016] Furthermore, the actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system are collected; the multi-objective optimization function is corrected based on the actual negative torque and actual braking pressure; the corrected multi-objective optimization function is used for control in the next cycle.

[0017] Based on the aforementioned technical means, by collecting the actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system, and comparing them with their respective target commands, the actual execution deviation of the electro-hydraulic braking force within the current control cycle can be obtained. The multi-objective optimization function is corrected based on the errors between the actual and target negative torques, and between the actual and target braking pressures, enabling it to incorporate factors such as execution-level lag, nonlinearity, or external disturbances into the control calculations of the next cycle. The corrected multi-objective optimization function is used in subsequent control cycles, allowing the braking force distribution scheme to be dynamically adjusted based on the execution results of the previous cycle, gradually reducing the cumulative deviation between the command value and the actual value.

[0018] Furthermore, the actual total braking force is determined based on the actual negative torque and the actual braking pressure; based on the error between the actual total braking force and the target total braking force, the compensation value of the integral term is determined, and the compensation value of the integral term is used to compensate for the target total braking force of the multi-objective optimization function in the next cycle.

[0019] Based on the aforementioned technical means, by collecting the actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system, the total braking force actually acting on the vehicle can be synthesized and compared with the target total braking force, thereby quantitatively assessing the execution deviation of the overall braking force of the system within the current control cycle. Based on this deviation, a compensation value for the integral term is determined, and this compensation value is used as a correction term for the target total braking force in the multi-objective optimization function of the next cycle. This allows the multi-objective optimization function to incorporate the accumulated deviation from historical cycles in subsequent calculations, gradually eliminating the error between the actual total braking force and the target total braking force, and making the actual total braking force closer to the driver's intention throughout the braking process.

[0020] Furthermore, when the vehicle encounters an abnormal situation, the hub motor is controlled to enter a zero-torque state, and the brake-by-wire system is controlled based on the target braking pressure; the abnormal situation includes at least one of the following: slip ratio exceeding the limit of any wheel, brake actuator failure, or communication abnormality.

[0021] Based on the above technical means, when an abnormal situation is detected in the vehicle, the hub motor is controlled to enter a zero-torque state to cut off the regenerative braking force output at the motor end, so as to avoid further deterioration of the slip ratio or control command conflict in the fault state due to the intervention of negative torque of the motor; at the same time, the control line braking system independently executes hydraulic braking based on the pre-calculated target braking pressure, so that the vehicle can still maintain basic braking capability in the abnormal state.

[0022] Furthermore, the vehicle's motion status information includes at least one of the following: body yaw rate, lateral acceleration, and wheel speed.

[0023] Based on the aforementioned technical methods, the collected vehicle yaw rate, lateral acceleration, and wheel speed together constitute a parameter set of vehicle motion state information. Specifically, the vehicle yaw rate directly reflects the vehicle's rotational state around its vertical axis, providing real-time feedback for yaw stability optimization; lateral acceleration characterizes the lateral forces acting on the vehicle during steering, corroborating the estimated road adhesion coefficient; and wheel speed indirectly reflects the tendency of wheel slippage or lock-up through the differences in wheel speeds, providing a basis for determining the adhesion limit during braking force distribution.

[0024] Secondly, this application provides a hub motor and brake-by-wire fusion control device, including a data acquisition module, a calculation module, and a control module; the data acquisition module is used to acquire vehicle motion state information and brake pedal travel information when the state of charge of the power battery is greater than or equal to a preset threshold; the calculation module is used to calculate the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle motion state information and brake pedal travel information; the control module is used to control the hub motor and the brake-by-wire system respectively based on the target negative torque and the target braking pressure.

[0025] Furthermore, the calculation module is also used to calculate the road adhesion coefficient of the current road surface based on the vehicle's motion state information; determine the driver's desired total braking force based on the brake pedal travel information; and calculate the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle's motion state information, the road adhesion coefficient, and the target total braking force.

[0026] Furthermore, the calculation module is also used to construct a multi-objective optimization function based on the vehicle's motion state information, road surface adhesion coefficient, and target total braking force. The optimization objectives of the multi-objective optimization function include: minimizing the total braking force error, minimizing the negative torque fluctuation of the hub motor, and optimizing the vehicle's yaw stability. Solving the multi-objective optimization function yields the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0027] Furthermore, the calculation module is also used to solve a multi-objective optimization function based on constraints to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system; wherein the constraints include at least one of the following: the target negative torque of the hub motor is less than or equal to the maximum negative torque of the motor when fully charged, the target braking pressure of the brake-by-wire system is less than or equal to the maximum pressure of the brake-by-wire system, and the target total braking force is less than or equal to the maximum friction force of the road surface.

[0028] Furthermore, the calculation module is also used to convert the multi-objective optimization function into a standard quadratic function; solve the standard quadratic function to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0029] Furthermore, the acquisition module is also used to acquire the actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system; the multi-objective optimization function is corrected based on the actual negative torque and actual braking pressure; the corrected multi-objective optimization function is used for control in the next cycle.

[0030] Furthermore, the calculation module is also used to determine the actual total braking force based on the actual negative torque and the actual braking pressure; and to determine the compensation value of the integral term based on the error between the actual total braking force and the target total braking force. The compensation value of the integral term is used to compensate for the target total braking force of the multi-objective optimization function in the next cycle. Furthermore, the control module is also used to control the wheel hub motors to enter a zero-torque state and control the brake-by-wire system based on the target braking pressure when abnormal conditions occur in the vehicle; wherein, abnormal conditions include at least one of the following: slip ratio exceeding the limit of any wheel, brake actuator failure, or communication abnormality.

[0031] Furthermore, the vehicle's motion status information includes at least one of the following: body yaw rate, lateral acceleration, and wheel speed.

[0032] Thirdly, this application provides a vehicle that includes: the hub motor and the brake-by-wire fusion control device described in the second aspect above.

[0033] Fourthly, this application provides a computer-readable storage medium storing computer program instructions that, when executed by a processor, implement the method described in the first aspect.

[0034] Fifthly, this application provides a computer program product including computer program instructions that, when executed by a processor, implement the method described in the first aspect.

[0035] It should be noted that the technical effects of any of the implementation methods in aspects two through five can be found in the technical effects of the corresponding implementation methods in aspect one, and will not be repeated here.

[0036] 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

[0037] Figure 1 A schematic diagram of the architecture of a hub motor and a brake-by-wire integrated control system provided by the present invention; Figure 2 A flowchart illustrating the fusion control method of a hub motor and brake-by-wire provided by the present invention; Figure 3 A flowchart illustrating a method for calculating target negative torque and target braking pressure provided by the present invention; Figure 4 A flowchart illustrating another hub motor and a brake-by-wire fusion control method provided by the present invention; Figure 5 A schematic diagram of the actuator of a hub motor and a brake-by-wire fusion control method provided by the present invention; Figure 6 This invention provides a schematic diagram of the composition of a hub motor and a brake-by-wire fusion control device. Figure 7 This is a schematic diagram of the structure of an electronic device provided by the present invention. Detailed Implementation

[0038] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0039] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0040] The following will describe in detail, with reference to the accompanying drawings, a calculation method, device, and electronic equipment for hub motor and brake-by-wire fusion control provided in this application.

[0041] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0042] The terms "first" and "second," etc., used in the specification and drawings of this application are used to distinguish different objects or to distinguish different treatments of the same object, rather than to describe a specific order of objects.

[0043] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0044] It should be noted that in the embodiments of this application, the words "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0045] To facilitate a clear description of the technical solutions of the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish the same or similar items with essentially the same function and effect. Those skilled in the art can understand that the terms "first" and "second" are not intended to limit the quantity or execution order.

[0046] In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0047] The embodiments provided in this application will now be described in detail with reference to the accompanying drawings.

[0048] The hub motor and drive-by-wire braking fusion control method provided in this application can be applied to, for example... Figure 1 In the hub motor and brake-by-wire integrated control system shown. For example... Figure 1 As shown, the hub motor and drive-by-wire braking fusion control system 10 of this application includes: a data acquisition device 11, a processing device 12, and a control device 13.

[0049] A communication connection is established between the acquisition device 11, the processing device 12, and the control device 13.

[0050] In some embodiments, the acquisition device 11 can acquire vehicle motion state information and brake pedal travel information. For example, the vehicle motion state information may include vehicle body yaw rate, lateral acceleration, and wheel speed; the brake pedal travel information may be the angular displacement of the brake pedal when it is depressed, the linear displacement of the brake pedal push rod, or the travel percentage data obtained by converting the raw voltage signal directly acquired by the travel sensor on the brake pedal.

[0051] In some embodiments, the acquisition device 11 can send the acquired information to the processing device 12 so that the processing device 12 can perform calculations on the acquired information.

[0052] In some embodiments, the acquisition device 11 may be a multi-source sensor. For example, the acquisition device 11 may be a high-precision displacement sensor, a yaw rate sensor, an inertial measurement unit, and wheel speed sensors mounted on the brake pedal.

[0053] In some embodiments, the processing device 12 can construct and solve a multi-objective optimization function based on the vehicle motion state information and brake pedal travel information sent by the acquisition device 11 to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0054] In some embodiments, the processing device 12 may also generate vehicle braking control commands and send them to the control device 13 to enable the control device 13 to control the vehicle's braking. The vehicle braking control commands may include a target negative torque of the hub motor and a target braking pressure of the brake-by-wire system, instructing the control device 13 to control the hub motor based on the target negative torque and the brake-by-wire system based on the target braking pressure. Alternatively, the vehicle braking control commands may be two commands: a first command including the target negative torque of the hub motor, instructing the control device 13 to control the hub motor based on the target negative torque; and a second command including the target braking pressure of the brake-by-wire system, instructing the control device 13 to control the brake-by-wire system based on the target braking pressure.

[0055] In some embodiments, the processing device 12 can be a server, such as a single server or a server cluster consisting of multiple servers. In some embodiments, the server cluster can also be a distributed cluster.

[0056] In some embodiments, the processing device 12 can be a terminal device, such as an in-vehicle terminal, mobile phone, tablet computer, desktop computer, laptop computer, handheld computer, notebook computer, ultra-mobile personal computer (UMPC), netbook, cellular phone, personal digital assistant (PDA), augmented reality (AR) / virtual reality (VR) device, etc. This application embodiment does not impose any special limitations on the specific form of the terminal device.

[0057] In some embodiments, the control device 13 can receive vehicle braking control commands sent from the processing device 12, and control the wheel hub motors and brake-by-wire system of the vehicle based on the received vehicle braking control commands, so as to realize braking control of the vehicle.

[0058] In some embodiments, the control device 13 may include a hub motor controller and a brake-by-wire controller; alternatively, the control device 12 may be a controller that integrates hub motor control and brake-by-wire control functions. For example, the control device 12 may be a chassis domain controller or a vehicle controller.

[0059] It should be noted that the system architecture described in the embodiments of this application is for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and does not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of system architecture, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0060] The hub motor and brake-by-wire fusion control method provided in this application can be applied to hub motor and brake-by-wire fusion control systems, such as... Figure 2 As shown, the hub motor and drive-by-wire braking fusion control method includes the following steps S201~S203: S201. When the state of charge of the power battery is greater than or equal to a preset threshold, collect the vehicle's motion status information and brake pedal travel information.

[0061] In some embodiments, a power battery refers to a rechargeable energy storage device that provides driving power to a vehicle. For example, a power battery may include lithium-ion power batteries, nickel-metal hydride power batteries, or solid-state power batteries, etc.

[0062] In some embodiments, the state of charge is a parameter describing the percentage of remaining charge in the battery, typically ranging from 0% to 100%.

[0063] In some embodiments, vehicle motion state information refers to various parameter data used to describe the current driving dynamics of the vehicle.

[0064] In some embodiments, the vehicle's motion state information includes at least one of the following: vehicle body yaw rate, lateral acceleration, and wheel speed.

[0065] Among them, the vehicle body yaw rate refers to the angular velocity of the vehicle rotating around its vertical axis, reflecting the degree of intensity of the vehicle's rotation around its center of mass.

[0066] Lateral acceleration refers to the acceleration that a vehicle generates perpendicular to the direction of travel during driving, and it characterizes the change in the vehicle's motion state when turning or subjected to lateral forces.

[0067] Wheel speed refers to the angular velocity or linear velocity of each wheel of a vehicle, reflecting how fast each wheel rotates.

[0068] In some embodiments, brake pedal travel information refers to data reflecting the amount of displacement of the brake pedal when it is pressed by the driver.

[0069] For example, brake pedal travel information can be the angular displacement of the brake pedal when it is depressed, or the linear displacement of the brake pedal push rod. Brake pedal travel information can also be the percentage of travel data obtained by converting the original voltage signal directly collected by the travel sensor on the brake pedal.

[0070] In some embodiments, vehicle motion state information and brake pedal travel information can be collected through sensors. For example, the current state of charge of the power battery can be obtained by the vehicle controller through the battery management system. When the state of charge value of the power battery is greater than or equal to a preset threshold, the collection process is triggered. The yaw rate of the vehicle body can be obtained by the yaw rate sensor, the lateral acceleration signal can be obtained by the inertial measurement unit, the real-time wheel speed information of the four wheels can be measured by the wheel speed sensors of each wheel, and the brake pedal travel signal can be collected in real time by the high-precision displacement sensor installed on the brake pedal.

[0071] S202. Based on the vehicle's motion state information and brake pedal travel information, calculate the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0072] In some embodiments, a hub motor refers to an electric motor directly mounted inside the wheel hub for driving the wheel. The hub motor operates in a non-regenerative negative torque mode, generating braking torque by controlling the inverter, while simultaneously dissipating DC bus energy in a braking resistor or through DC-DC isolation conversion or an isolated DC-DC converter to ensure that the battery charging current is zero or negative. Exemplarily, the hub motor can be an internal rotor hub motor or an external rotor hub motor, and can be a permanent magnet synchronous motor or an asynchronous induction motor.

[0073] In some embodiments, the target negative torque refers to the expected reverse torque value output by the hub motor in regenerative braking mode, which acts on the wheel to produce a deceleration effect.

[0074] In some embodiments, a brake-by-wire system refers to a braking system that transmits the driver's braking intention via electrical signals and generates braking force by an actuator driven by an electronic control unit. For example, a brake-by-wire system may be an electro-hydraulic braking system or an electromechanical braking system.

[0075] In some embodiments, the target braking pressure refers to the hydraulic pressure or mechanical clamping force that the brake-by-wire system is expected to establish at the wheel brakes.

[0076] In some embodiments, step S202 can be implemented as the following steps a1 to a3.

[0077] a1. Calculate the road adhesion coefficient of the current road surface based on the vehicle's motion state information.

[0078] In some embodiments, the road surface adhesion coefficient is a quantitative indicator of the maximum frictional force that can be transmitted between the tire and the road surface, reflecting the upper limit of the road surface's ability to provide longitudinal and lateral forces.

[0079] In some embodiments, the current vehicle speed of each wheel can be estimated in real time using an adaptive estimation algorithm based on the values ​​of the wheel speed sensors of each wheel, and the slip ratio can be further calculated. Based on the slip ratio of each wheel and the vehicle speed, the current road surface adhesion coefficient can be calculated using the recursive least squares method.

[0080] For example, the wheel speed pulse signal at the current moment can be collected and converted into an angular velocity value, while the longitudinal acceleration signal can be obtained from the vehicle's inertial measurement unit. Then, based on the collected wheel speed signals and longitudinal acceleration signals, an adaptive estimation algorithm based on Kalman filtering is used to estimate the longitudinal speed of each wheel relative to the road surface in real time. Next, based on the difference between the estimated wheel speed and the corresponding wheel speed, and the estimated wheel speed itself, the current slip ratio value of each wheel is calculated according to the slip ratio definition. Further, using the slip ratio value of each wheel and the corresponding wheel speed as input, a recursive least squares algorithm with a forgetting factor is used, with the peak adhesion coefficient in the tire longitudinal slip characteristic curve as the parameter to be identified, to calculate the current road surface adhesion coefficient value through real-time iterative calculation.

[0081] a2. Determine the driver's desired total braking force based on brake pedal travel information.

[0082] In some embodiments, the target total braking force refers to the total braking force expected to be generated by all braking actuators of the vehicle, which directly corresponds to the vehicle deceleration expected by the driver.

[0083] In some embodiments, the target total braking force expected by the driver corresponding to the current brake pedal travel information can be determined based on the brake pedal characteristic curve or mapping relationship pre-stored in the computing device using the collected brake pedal travel information.

[0084] For example, a high-precision angular displacement sensor installed at the brake pedal shaft collects the angular displacement signal when the brake pedal is depressed in real time. After analog-to-digital conversion and filtering, the signal is converted into the corresponding pedal travel percentage value. By performing a difference operation between the pedal travel percentage value obtained in the current sampling period and the pedal travel percentage value stored in the previous sampling period, and then dividing by the sampling time interval, the pedal travel change rate value at the current moment is obtained. Subsequently, the driver's desired total braking force value corresponding to the current pedal travel and the rate of change of travel is determined in real time through table lookup and linear interpolation.

[0085] a3. Based on the vehicle's motion state information, road surface adhesion coefficient, and target total braking force, calculate the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0086] S203, based on the target negative torque and the target braking pressure, respectively control the hub motor and the brake-by-wire system.

[0087] In some embodiments, a target negative torque command can be sent to the wheel hub motor controller via the vehicle controller local area network bus, and a target braking pressure command can be sent to the brake-by-wire system controller via the vehicle controller local area network bus. The wheel hub motor controller controls the wheel hub motor to perform regenerative braking according to the received target negative torque command, and the brake-by-wire system controller controls the brake actuator to generate braking force according to the received target braking pressure command.

[0088] In some embodiments, when an abnormal situation occurs in the vehicle, the hub motor is controlled to enter a zero-torque state, and the brake-by-wire system is controlled based on the target braking pressure; wherein the abnormal situation includes at least one of the following: slip ratio exceeding the limit of any wheel, brake actuator failure, or communication abnormality.

[0089] In some embodiments, an abnormal situation refers to a special condition that deviates from the normal state during the operation of the vehicle braking system. For example, an abnormal situation may include a situation where any wheel experiences an excessive slip ratio. An excessive slip ratio means that the wheel's slip ratio exceeds a preset stability control threshold, which may cause wheel lock-up or excessive slippage. An abnormal situation may also include a brake actuator malfunction. A brake actuator malfunction refers to a functional failure of the actuator, such as the hub motor controller, brake-by-wire system controller, the hub motor itself, the brake pressure regulating unit, or the brake caliper. A brake actuator malfunction may manifest as the motor failing to respond to torque commands, brake pressure failing to build up, or abnormal brake pressure response. An abnormal situation may also include a communication anomaly. A communication anomaly refers to an interruption, signal delay, or data error in the communication link between the computing device and the hub motor controller, or between the computing device and the brake-by-wire system controller. A communication anomaly may manifest as lost controller area network bus messages, cyclic redundancy check errors, or communication timeouts.

[0090] In some embodiments, zero torque state refers to the free-running state in which the hub motor neither outputs drive torque nor regenerative braking torque. Zero torque state is a safe operating mode for the hub motor. In this state, the hub motor controller stops outputting drive current to the motor windings, the hub motor no longer generates any active torque, and the hub motor can rotate freely with the wheel.

[0091] For example, when an abnormal situation is detected, a zero-torque command is immediately sent to the hub motor controller to put the hub motor into a zero-torque state. At the same time, the target total braking force calculated in the current control cycle is converted into the target braking pressure and sent to the brake-by-wire system controller through the available communication channel. The brake-by-wire system controller then controls the brake-by-wire system to perform braking based on the target braking pressure.

[0092] In some embodiments, when an abnormal situation is detected in the vehicle, the hub motor is controlled to enter a zero-torque state to cut off the regenerative braking force output at the motor end, so as to avoid further deterioration of the slip ratio or control command conflict in the fault state due to the intervention of negative torque of the motor; at the same time, the control line braking system independently executes hydraulic braking based on the pre-calculated target braking pressure, so that the vehicle can still maintain basic braking capability in the abnormal state.

[0093] In some embodiments, such as Figure 3 As shown, step a3 above can be implemented as the following steps S301~S302.

[0094] S301. Construct a multi-objective optimization function based on the vehicle's motion state information, road surface adhesion coefficient, and target total braking force.

[0095] The optimization objectives of the multi-objective optimization function include: minimizing the total braking force error, minimizing the negative torque fluctuation of the hub motor, and optimizing the vehicle's yaw stability.

[0096] In some embodiments, a multi-objective optimization function refers to a mathematical expression used to comprehensively measure the degree to which each objective is satisfied when there are multiple interrelated or even conflicting optimization objectives. For example, the multi-objective optimization function can be a function that combines the three optimization objectives—minimizing total braking force error, minimizing wheel hub motor negative torque fluctuation, and optimizing vehicle yaw stability—through a weighted summation.

[0097] In some embodiments, total braking force error refers to the difference between the desired target total braking force and the actual total braking force generated by the hub motor and the brake-by-wire system. Minimizing the total braking force tracking error means minimizing the deviation between the actual generated total braking force and the braking force required by the driver.

[0098] In some embodiments, hub motor negative torque ripple refers to the degree of drastic change in the reverse torque output by the hub motor during regenerative braking over time. Minimizing hub motor negative torque ripple reduces motor current surges, improves energy recovery smoothness, and extends motor life.

[0099] In some embodiments, vehicle yaw stability refers to the vehicle's ability to maintain its intended direction of travel and avoid oversteer or understeer during braking. For example, vehicle yaw stability can be quantified by the deviation of the vehicle body yaw rate from the desired yaw rate, assessed by the center-of-gravity sideslip angle and its rate of change, or characterized by the proximity of the additional yaw moment generated by the left and right wheel braking force distribution to the yaw moment required to maintain stability. Optimal vehicle yaw stability ensures directional controllability and driving safety during braking by suppressing yaw rate deviations or sideslip angle increases.

[0100] In some embodiments, a multi-objective optimization function is constructed based on the vehicle's motion state information, road surface adhesion coefficient, and target total braking force. Minimizing the total braking force error, minimizing the negative torque fluctuation of the in-wheel motor, and optimizing vehicle yaw stability are simultaneously used as optimization objectives. This allows for a comprehensive consideration of braking accuracy, energy recovery smoothness, and vehicle attitude maintenance during the solution process. By solving this multi-objective optimization function, the target negative torque of the in-wheel motor and the target braking pressure of the brake-by-wire system can be obtained, enabling coordinated distribution of electric motor power and hydraulic braking force while meeting the total braking force requirements. The optimization of the motor's negative torque smoothness reduces torque abrupt changes during regenerative braking intervention, while the optimization of yaw stability maintains the vehicle's direction of travel through the rational distribution of braking force between the left and right wheels.

[0101] In some embodiments, adjustable weight coefficients can be assigned to the optimization objectives in the multi-objective optimization function.

[0102] In some embodiments, the weighting coefficient refers to the weighted value assigned to each optimization objective in the multi-objective optimization function, and the magnitude of the weighting coefficient reflects the importance of the corresponding optimization objective in the overall optimization.

[0103] In some embodiments, a multi-objective optimization function is solved based on constraints to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system; wherein the constraints include at least one of the following: the target negative torque of the hub motor is less than or equal to the maximum negative torque of the motor when fully charged, the target braking pressure of the brake-by-wire system is less than or equal to the maximum pressure of the brake-by-wire system, and the target total braking force is less than or equal to the maximum friction force of the road surface.

[0104] In some embodiments, constraints refer to the restrictive conditions that decision variables in an optimization problem must satisfy, and constraints ensure that the optimization result is within the feasible region.

[0105] In some embodiments, the target negative torque of the hub motor is an independent control command assigned to each hub motor, and the target negative torque of the hub motor is limited by the current speed and temperature of the hub motor. The maximum negative torque of the motor in a fully charged state is an upper limit calculated in real time by the power battery management system based on the battery's state of charge, temperature, and health status, and sent to the hub motor controller.

[0106] In some embodiments, the brake pressure of each wheel is an independent pressure command assigned to each wheel brake, and the brake pressure of each wheel is limited by the physical capabilities of the hydraulic unit or mechanical actuator of the brake-by-wire system.

[0107] In some embodiments, the maximum pressure of the brake-by-wire system is an inherent upper limit determined by the braking system hardware design, or the maximum pressure of the brake-by-wire system can be a limit that is dynamically adjusted after taking into account factors such as temperature.

[0108] An example of how a multi-objective optimization function can be constructed is shown below.

[0109]

[0110] in, This represents the minimum value. The weighting coefficient represents the total braking force error. The weighting coefficient represents the negative torque fluctuation of the hub motor. The weighting coefficient represents the vehicle's yaw stability, and this coefficient can be adjusted according to the actual scenario. Indicates the total braking force of the target. Indicates the actual total braking force. For the first The negative torque applied by each hub motor (positive torque represents braking). This represents the yaw rate generated by the vehicle. This represents the target's yaw rate.

[0111] Wherein, the yaw moment is , For the first The lever arm of the wheel's center of mass. The radius of the wheel's rolling motion. The pressure-braking force conversion coefficient, This is a linear control braking force. The yaw rate and yaw moment have a linear relationship. Therefore, the yaw rate can be directly replaced by the yaw torque.

[0112] For example, the method for constructing constraints can be as follows.

[0113]

[0114]

[0115]

[0116]

[0117] in, The pressure for linear control should be less than the maximum pressure for linear control. The radius of the wheel's rolling motion. This is the pressure-braking force conversion coefficient. The converted braking force should be less than the maximum friction force of the road surface to prevent wheel lock-up. Indicates the road surface adhesion coefficient. The first one represents the dynamic change Vertical load on each wheel and road adhesion coefficient Together, they constitute the upper limit of the braking force of the wheel.

[0118] S302. Solve the multi-objective optimization function to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0119] In some embodiments, the multi-objective optimization function can be converted into a standard quadratic function.

[0120] An example, the method for converting to a standard quadratic form can be as follows.

[0121] First, the decision variables of the multi-objective optimization function are: The total braking force can be written as ,in The yaw moment can be written as , , Let be the center-of-mass lever arm vector for each wheelset. Wherein, This indicates the target negative torque of the hub motors for all four wheels. This indicates the target braking pressure of the brake-by-wire system for all four wheels.

[0122] Next, the various optimization objectives are expanded, and like terms are combined to obtain... .in This is a constant term, which can be ignored in the quadratic programming algorithm and does not affect the optimization result. This represents a diagonal matrix.

[0123] Then, let , .in and All are symmetric matrices, and their outer product matrix is... It is a positive semi-definite matrix, and its outer product matrix is... It is a positive semi-definite matrix, D is a diagonal matrix with diagonal elements ≥ 0, therefore it is also a symmetric positive semi-definite matrix, and the weights are... In summary, Q is a symmetric positive semi-definite matrix.

[0124] Finally, let H = 2Q and f = -2b. The final multi-objective optimization function can be written as a standard quadratic form.

[0125] In some embodiments, the standard quadratic function is solved to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0126] For example, the H matrix, f vector, and constraints in the transformed standard quadratic function can be passed as input parameters to the quadratic programming solver. The quadratic programming solver uses a numerical optimization algorithm to calculate the optimal decision variable vector that minimizes the value of the standard quadratic function. From this optimal decision variable vector, the target negative torque values ​​of each hub motor and the target braking pressure values ​​of each wheel-line braking system can be extracted.

[0127] In some embodiments, after controlling the hub motor and the brake-by-wire system based on the target negative torque and the target braking pressure, respectively, the actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system are collected.

[0128] For example, after controlling the hub motor and the brake-by-wire system separately, the internal status message of the hub motor controller can be read in real time from the hub motor controller via the vehicle controller local area network bus to extract the actual negative torque value of the hub motor; at the same time, the internal status message of the brake-by-wire system controller can be read in real time from the brake-by-wire system controller via the vehicle controller local area network bus to extract the actual braking pressure value of each wheel.

[0129] In some embodiments, the multi-objective optimization function is corrected based on the actual negative torque and the actual braking pressure, and the corrected multi-objective optimization function is used for control in the next cycle.

[0130] In some embodiments, the actual total braking force is determined based on the actual negative torque and the actual braking pressure; the compensation value of the integral term is determined based on the error between the actual total braking force and the target total braking force, and the compensation value of the integral term is used to compensate for the target total braking force of the multi-objective optimization function in the next cycle.

[0131] In some embodiments, actual negative torque refers to the actual reverse torque value output by the hub motor in regenerative braking mode.

[0132] In some embodiments, actual braking pressure refers to the actual hydraulic pressure or mechanical clamping force value established at the wheel brakes by the brake-by-wire system.

[0133] In some embodiments, the actual total braking force refers to the real total braking force generated on the vehicle by the combined action of the negative torque actually output by the hub motor and the braking pressure actually established by the brake-by-wire system.

[0134] In some embodiments, the compensation value of the integral term refers to the correction amount obtained by integral calculation based on the cumulative deviation between the actual total braking force and the target total braking force.

[0135] In some embodiments, a deviation signal can be obtained by calculating the difference between the actual total braking force and the target total braking force. This deviation signal is then input into an integrator for accumulation and multiplied by an integral gain coefficient to obtain a compensation value for the integral term. Subsequently, the compensation value of the integral term is added to the target total braking force for the next cycle, and the result is used as the corrected target total braking force and input into the multi-objective optimization function for calculation in the next cycle.

[0136] In some embodiments, by collecting the actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system, and comparing them with their respective target commands, the actual execution deviation of the electro-hydraulic braking force within the current control cycle can be obtained. Based on the errors between the actual negative torque and the target negative torque, and between the actual braking pressure and the target braking pressure, the multi-objective optimization function is corrected, enabling it to incorporate factors such as execution-level lag, nonlinearity, or external disturbances into the control calculations of the next cycle. The corrected multi-objective optimization function is used in subsequent control cycles, allowing the braking force distribution scheme to be dynamically adjusted based on the execution results of the previous cycle, gradually reducing the cumulative deviation between the command value and the actual value.

[0137] For example, such as Figure 4 As shown, the process begins with step S1: collecting the state of charge of the power battery and determining if it is greater than or equal to a preset threshold. If it is, proceed to step S2; otherwise, proceed to step S5. Step S2: collecting vehicle motion information and brake pedal travel information, calculating the current road adhesion coefficient and the driver's desired target total braking force. Step S3: constructing a multi-objective optimization function with the objectives of minimizing total braking force error, minimizing hub motor negative torque fluctuation, and optimizing vehicle yaw stability. Solving this function yields the target negative torque of the hub motor and the target pressure of the brake-by-wire system. Step S4: executing commands and providing feedback correction for the hub motor and brake-by-wire system. Comparing the actual negative torque of the hub motor and the actual pressure of the brake-by-wire system obtained after executing the commands with the target total braking force, and adding the error as a compensation term to the multi-objective optimization function. Step S5: exiting the hub motor and brake-by-wire fusion control method. The process ends after executing either step S4 or S5.

[0138] For example, such as Figure 5 As shown, after receiving vehicle motion state information and brake pedal travel information from the yaw rate sensor, inertial measurement unit, brake pedal, and battery management system, the vehicle controller calculates the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system. Then, in the modular drive system, it controls the hub motor and brake-by-wire system to execute commands and uses sensors to collect the actual total braking force for feedback correction.

[0139] The above primarily describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, the computing device for the fusion control of the hub motor and brake-by-wire includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Experts may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0140] like Figure 6 As shown, the hub motor and drive-by-wire braking fusion control device 1000 includes: a data acquisition module 1001, a calculation module 1002, and a control module 1003.

[0141] The acquisition module 1001 is used to acquire vehicle motion state information and brake pedal travel information when the state of charge of the power battery is greater than or equal to a preset threshold; the calculation module 1002 is used to calculate the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle motion state information and brake pedal travel information; the control module 1003 is used to control the hub motor and the brake-by-wire system respectively based on the target negative torque and the target braking pressure.

[0142] Furthermore, the calculation module 1002 is also used to calculate the road surface adhesion coefficient of the current road surface based on the vehicle's motion state information; determine the driver's desired total braking force based on the brake pedal travel information; and calculate the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle's motion state information, the road surface adhesion coefficient, and the target total braking force.

[0143] Furthermore, the calculation module 1002 is also used to construct a multi-objective optimization function based on the vehicle's motion state information, road surface adhesion coefficient, and target total braking force; wherein, the optimization objectives of the multi-objective optimization function include: minimizing the total braking force error, minimizing the negative torque fluctuation of the hub motor, and optimizing the vehicle's yaw stability; solving the multi-objective optimization function yields the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0144] Furthermore, the calculation module 1002 is also used to solve a multi-objective optimization function based on constraints to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system; wherein the constraints include at least one of the following: the target negative torque of the hub motor is less than or equal to the maximum negative torque of the motor when fully charged, the target braking pressure of the brake-by-wire system is less than or equal to the maximum pressure of the brake-by-wire system, and the target total braking force is less than or equal to the maximum friction force of the road surface.

[0145] Furthermore, the calculation module 1002 is also used to convert the multi-objective optimization function into a standard quadratic function; solve the standard quadratic function to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

[0146] Furthermore, the acquisition module 1001 is also used to acquire the actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system; to correct the multi-objective optimization function based on the actual negative torque and actual braking pressure; and to use the corrected multi-objective optimization function for control in the next cycle.

[0147] Furthermore, the calculation module 1002 is also used to determine the actual total braking force based on the actual negative torque and the actual braking pressure; and to determine the compensation value of the integral term based on the error between the actual total braking force and the target total braking force. The compensation value of the integral term is used to compensate for the target total braking force of the multi-objective optimization function in the next cycle. Furthermore, the control module 1003 is also used to control the wheel hub motor to enter a zero-torque state when the vehicle encounters an abnormal situation, and to control the brake-by-wire system based on the target braking pressure; wherein the abnormal situation includes at least one of the following: any wheel slip ratio exceeding the limit, brake actuator failure, or communication abnormality.

[0148] Furthermore, the vehicle's motion status information includes at least one of the following: body yaw rate, lateral acceleration, and wheel speed.

[0149] like Figure 7 As shown, the electronic device 1100 includes, but is not limited to, a processor 1101 and a memory 1102.

[0150] The aforementioned memory 1102 is used to store the executable instructions of the aforementioned processor 1101. It is understood that the aforementioned processor 1101 is configured to execute instructions to implement the hub motor and brake-by-wire fusion control method in the above embodiments.

[0151] It should be noted that those skilled in the art will understand that Figure 7 The electronic device structure shown does not constitute a limitation on electronic device 1100; electronic device 1100 may include, but is not limited to, other electronic devices. Figure 7 This may indicate more or fewer components, or combinations of certain components, or different component arrangements.

[0152] Processor 1101 is the control center of electronic device 1100. It connects various parts of the electronic device via various interfaces and lines. By running or executing software programs and / or modules stored in memory 1102, and by calling data stored in memory 1102, it performs various functions and processes data of electronic device 1100, thereby providing overall monitoring of electronic device 1100. Processor 1101 may include one or more processing units. Optionally, processor 1101 may integrate an application processor and a modem processor. The application processor mainly handles the operating system, user interface, and applications, while the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into processor 1101.

[0153] The memory 1102 can be used to store software programs and various data. The memory 1102 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, application programs required by at least one functional module (such as a determination unit, processing unit, etc.), etc. Furthermore, the memory 1102 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0154] In an exemplary embodiment, a computer-readable storage medium including instructions is also provided, such as a memory 1102 including instructions, which can be executed by a processor 1101 of an electronic device 1100 to implement the hub motor and brake-by-wire fusion control method in the above embodiments.

[0155] In actual implementation, Figure 6 The functions of the acquisition module 1001, calculation module 1002, and control module 1003 can all be derived from... Figure 7 The processor 1101 calls the computer program stored in the memory 1102 to implement the process. The specific execution process can be found in the method section of the previous embodiment, and will not be repeated here.

[0156] Optionally, the computer-readable storage medium may be a non-transitory computer-readable storage medium, such as a read-only memory (ROM), random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device.

[0157] In an exemplary embodiment, this application also provides a computer program product including one or more instructions, which can be executed by the processor 1101 of the electronic device 1100 to complete the calculation method for the fusion control of the hub motor and the brake-by-wire in the above embodiment.

[0158] It should be noted that when one or more instructions in the computer-readable storage medium or computer program product are executed by the processor of an electronic device, they implement the various processes of the above method embodiments and achieve the same technical effect as the above method. To avoid repetition, they will not be described again here.

[0159] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0160] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0161] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the classified units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0162] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0163] 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 readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, essentially, or the part that contributes to the prior art, or a complete or partial classification of the technical solution, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0164] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A hub motor and a brake-by-wire fusion control method, characterized in that, The method includes: When the state of charge of the power battery is greater than or equal to a preset threshold, the vehicle's motion status information and brake pedal travel information are collected. Based on the vehicle's motion state information and the brake pedal travel information, the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system are calculated. Based on the target negative torque and the target braking pressure, the hub motor and the brake-by-wire system are controlled respectively.

2. The hub motor and drive-by-wire braking fusion control method according to claim 1, characterized in that, The calculation of the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle's motion state information and the brake pedal travel information includes: The road surface adhesion coefficient of the current road surface is calculated based on the vehicle's motion state information; The driver's desired total braking force is determined based on the brake pedal travel information. Based on the vehicle's motion state information, the road surface adhesion coefficient, and the target total braking force, the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system are calculated.

3. The hub motor and drive-by-wire braking fusion control method according to claim 2, characterized in that, The calculation of the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle's motion state information, the road surface adhesion coefficient, and the target total braking force includes: A multi-objective optimization function is constructed based on the vehicle's motion state information, the road surface adhesion coefficient, and the target total braking force; wherein, the optimization objectives of the multi-objective optimization function include: minimizing the total braking force error, minimizing the negative torque fluctuation of the wheel hub motor, and optimizing the vehicle's yaw stability; Solving the multi-objective optimization function yields the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

4. The hub motor and drive-by-wire braking fusion control method according to claim 3, characterized in that, Solving the multi-objective optimization function yields the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system, including: Based on the constraints, the multi-objective optimization function is solved to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system. The constraints include at least one of the following: the target negative torque of the hub motor is less than or equal to the maximum negative torque of the motor when fully charged; the target braking pressure of the brake-by-wire system is less than or equal to the maximum pressure of the brake-by-wire system; and the target total braking force is less than or equal to the maximum friction force of the road surface.

5. The hub motor and drive-by-wire braking fusion control method according to claim 3, characterized in that, Solving the multi-objective optimization function to obtain the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system includes: The multi-objective optimization function is converted into a standard quadratic function; Solving the standard quadratic function yields the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system.

6. The hub motor and drive-by-wire braking fusion control method according to claim 3, characterized in that, Based on the target negative torque and the target braking pressure, after controlling the hub motor and the brake-by-wire system respectively, the method further includes: The actual negative torque of the hub motor and the actual braking pressure of the brake-by-wire system are collected. The multi-objective optimization function is corrected based on the actual negative torque and the actual braking pressure; the corrected multi-objective optimization function is used for control in the next cycle.

7. The hub motor and drive-by-wire braking fusion control method according to claim 6, characterized in that, The correction of the multi-objective optimization function based on the actual negative torque and actual braking pressure includes: The actual total braking force is determined based on the actual negative torque and the actual braking pressure. Based on the error between the actual total braking force and the target total braking force, a compensation value for the integral term is determined. The compensation value for the integral term is used to compensate for the target total braking force of the multi-objective optimization function in the next cycle.

8. The hub motor and drive-by-wire braking fusion control method according to claim 1, characterized in that, The step of controlling the hub motor and the brake-by-wire system based on the target negative torque and the target braking pressure includes: When the vehicle experiences an abnormal situation, the hub motor is controlled to enter a zero-torque state, and the brake-by-wire system is controlled based on the target braking pressure. The abnormal conditions include at least one of the following: any wheel slip ratio exceeding the limit, brake actuator failure, or communication abnormality.

9. The hub motor and drive-by-wire braking fusion control method according to claim 1, characterized in that, The vehicle's motion status information includes at least one of the following: Vehicle body yaw rate, lateral acceleration, and wheel speed.

10. A hub motor and a brake-by-wire fusion control device, characterized in that, The hub motor and brake-by-wire fusion control device includes a data acquisition module, a calculation module, and a control module; The acquisition module is used to acquire vehicle motion state information and brake pedal travel information when the state of charge of the power battery is greater than or equal to a preset threshold. The calculation module is used to calculate the target negative torque of the hub motor and the target braking pressure of the brake-by-wire system based on the vehicle's motion state information and the brake pedal travel information. The control module is used to control the hub motor and the brake-by-wire system respectively based on the target negative torque and the target braking pressure.

11. A hub motor and drive-by-wire braking fusion control system, characterized in that, include: One or more processors; Memory, which stores computer programs; When the computer program is executed by the one or more processors, the hub motor and brake-by-wire fusion control system implements the hub motor and brake-by-wire fusion control method as described in any one of claims 1 to 9.

12. A vehicle, characterized in that, The vehicle is controlled using the hub motor and brake-by-wire fusion control method as described in any one of claims 1-9.

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