Vehicle control method and device and vehicle

Abstract

The embodiment of the invention relates to the technical field of vehicles, and discloses a vehicle control method and device and a vehicle. The vehicle control method comprises the steps that whether the vehicle is in a target state or not is determined, and under the condition that the vehicle is in the target state, cooperative control is conducted on the vehicle based on regenerative braking control, steering control and suspension control. Wherein the target state is a state in which an electro-mechanical braking (EMB) of the vehicle cannot provide braking force. According to the technical scheme provided by the embodiment of the invention, the braking effect and the driving stability of the vehicle can be improved.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to a vehicle control method, device, and vehicle. Background Technology

[0002] Electro-mechanical brake (EMB) is a brake-by-wire system that eliminates the need for hydraulic lines and directly drives the brake caliper via an electric motor.

[0003] In related technologies, when the EMB (Electronic Braking Module) fails, its braking capability may be completely lost, thus requiring braking compensation through backup EMB, redundant braking, or other methods. However, current backup braking methods are relatively simple, and even when multiple braking methods are used simultaneously, uneven distribution of braking force can easily lead to vehicle instability and energy waste. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a vehicle control method, device and vehicle that improves the braking effect and driving stability of the vehicle.

[0005] In a first aspect, embodiments of this application provide a vehicle control method, the method comprising: determining whether the vehicle is in a target state; and, if the vehicle is in the target state, performing coordinated control of the vehicle based on regenerative braking control, steering control, and suspension control. The target state is a state in which the vehicle's EMB (Electronic Braking Brake) cannot provide braking force.

[0006] The technical solution provided in this application, when the EMB (Electronic Braking Brake) cannot provide braking force, coordinates regenerative braking control, steering control, and suspension control to achieve coordinated vehicle control, avoiding the problems of low fault tolerance and braking effect of a single braking backup. While improving braking control effect through multiple braking backups, it effectively enhances vehicle stability during braking. For example, steering control generates yaw moment to counteract vehicle braking deviation or fishtailing tendencies, improving vehicle stability and braking capacity. Simultaneously, it links with suspension control to improve the efficiency of tire braking force utilization (such as friction braking force), effectively avoiding braking failure and vehicle instability when the EMB fails.

[0007] One possible implementation involves coordinated vehicle control based on regenerative braking control, steering control, and suspension control. Specifically, this involves: determining the vehicle's required braking force and driving state parameters; and, based on these parameters, optimizing the regenerative braking force (for regenerative braking control), the steering angle (for steering control), and the suspension force (for suspension control) to obtain target regenerative braking force, target steering angle, and target suspension force, with the goal of providing the required braking force and achieving a driving stability threshold. The vehicle is then coordinated based on these target regenerative braking force, target steering angle, and target suspension force. This technical solution, aiming to meet the vehicle's braking requirements and driving stability, determines the optimal target regenerative braking force, target steering angle, and target suspension force through multi-objective function coordination, further improving the vehicle's braking effect and driving stability while highly matching the driver's braking needs. One possible implementation involves optimizing the regenerative braking force (for regenerative braking control), steering angle (for steering control), and suspension force (for suspension control) based on driving state parameters, with the goal of the vehicle providing the required braking force and achieving a driving stability threshold. This optimization yields the target regenerative braking force, target steering angle, and target suspension force. Specifically, this can be achieved by: determining the target acceleration based on the required braking force; determining the target yaw rate when the vehicle's driving stability reaches the driving stability threshold based on the driving state parameters; and optimizing the regenerative braking force (for regenerative braking control), steering angle (for steering control), and suspension force (for suspension control) based on the target acceleration and target yaw rate. This approach uses target angular velocity and target yaw rate to characterize the vehicle's braking and driving stability requirements, respectively, making the optimization process more efficient, convenient, and computationally savvy.

[0008] One possible implementation involves optimizing the regenerative braking force for regenerative braking control, the steering angle for steering control, and the suspension force for suspension control based on the target acceleration and target yaw rate. This yields the target regenerative braking force, target steering angle, and target suspension force. Specifically, this can be achieved by solving for the target regenerative braking force, target steering angle, and target suspension force using a pre-constructed multi-objective function. The multi-objective function is constructed with the objectives of minimizing the acceleration difference between the vehicle's acceleration and the target acceleration, and minimizing the yaw rate difference between the vehicle's yaw rate and the target yaw rate. This technical solution constructs a multi-objective function that minimizes the acceleration difference and yaw rate difference, ensuring that the acceleration and yaw rate corresponding to the determined target regenerative braking force, target steering angle, and target suspension force closely match the target acceleration and target yaw rate, thus satisfying braking and driving stability requirements.

[0009] One possible approach is to determine the mapping relationship between the target yaw rate and target acceleration, and the target regenerative braking force, target steering angle, and target suspension action force, based on a vehicle dynamics model. By determining the acceleration and yaw rate corresponding to the regenerative braking force, steering angle, and suspension action force through the vehicle dynamics model, the complex vehicle dynamics relationships are transformed into controllable mathematical relationships. This enables accurate prediction of the acceleration and yaw rate corresponding to different regenerative braking forces, steering angles, and suspension action forces, effectively improving the convenience and accuracy of the multi-objective optimization process.

[0010] One possible implementation involves solving for the target regenerative braking force, target steering angle, and target suspension action force based on a pre-constructed multi-objective function. Specifically, this can be achieved by generating multiple combinations based on different regenerative braking forces, steering angles, and suspension action forces, and determining the vehicle acceleration and yaw rate for each combination. Based on the target acceleration, target yaw rate, and the vehicle acceleration and yaw rate corresponding to each combination, the objective function value of the multi-objective function for each combination is calculated. The regenerative braking force, steering angle, and suspension action force corresponding to the combination with the smallest objective function value among the multiple combinations are determined as the target regenerative braking force, target steering angle, and target suspension action force. The objective function value is a weighted sum of the acceleration difference between the vehicle acceleration and the target acceleration, and the yaw rate difference between the vehicle yaw rate and the target yaw rate.

[0011] One possible implementation is to determine the required braking force based on the vehicle's brake pedal opening and speed. Determining the target acceleration based on the required braking force can be specifically achieved by determining the target acceleration in an acceleration mapping table based on the brake pedal opening and vehicle speed. This acceleration mapping table includes the mapping relationship between brake pedal opening, vehicle speed, and target acceleration. Determining the target acceleration through an acceleration mapping table is more efficient and controllable, and users can flexibly adjust the acceleration mapping table according to actual needs, improving the user experience.

[0012] One possible implementation involves using driving state parameters including: vehicle wheelbase, mass, speed, wheel lateral stiffness, and front wheel steering angle. These parameters accurately reflect the vehicle's stability and driving status, facilitating timely control and adjustments based on these conditions.

[0013] One possible implementation, the vehicle control method provided in this application embodiment, further includes: when the vehicle is in a target state and the regenerative braking control fails, performing coordinated control of the vehicle based on steering control and suspension control. In the event of a failure in the backup regenerative braking control, vehicle stability is ensured through steering control and suspension control, effectively avoiding vehicle instability when both EMB braking and backup regenerative braking fail.

[0014] One possible implementation, the vehicle control method provided in this application embodiment, further includes: when the EBM fails, but the braking force that the EBM can provide is higher than a preset braking force threshold, performing coordinated control of the vehicle based on the EBM and regenerative braking control. When the EBM has not completely failed and can still provide a certain amount of braking force, the braking resources of the EBM are effectively utilized, and braking control is achieved in coordination with regenerative braking.

[0015] Secondly, this application provides a vehicle control device, which includes a processing module and a control module.

[0016] The aforementioned processing module is used to determine whether the vehicle is in a target state. The target state is a state where the vehicle's EMB (Electronic Braking System) cannot provide braking force.

[0017] The aforementioned control module is used to coordinate the control of the vehicle based on regenerative braking control, steering control, and suspension control when the vehicle is in the target state.

[0018] One possible implementation involves the aforementioned control module specifically used to: determine the vehicle's required braking force and driving state parameters; based on the driving state parameters, with the goal of the vehicle providing the required braking force and achieving a driving stability threshold, optimize the regenerative braking force for regenerative braking control, the steering angle for steering control, and the suspension action force for suspension control to obtain target regenerative braking force, target steering angle, and target suspension action force; and then perform coordinated control of the vehicle based on the target regenerative braking force, target steering angle, and target suspension action force.

[0019] One possible implementation is that the aforementioned control module is specifically used to: determine the target acceleration based on the required braking force; determine the target yaw rate when the vehicle's driving stability reaches the driving stability threshold based on the driving state parameters; and optimize the regenerative braking force of regenerative braking control, the steering angle of steering control, and the suspension action force of suspension control based on the target acceleration and the target yaw rate to obtain the target regenerative braking force, the target steering angle, and the target suspension action force.

[0020] One possible implementation is that the aforementioned control module is specifically used to: solve for the target regenerative braking force, the target steering angle, and the target suspension action force based on a pre-constructed multi-objective function. The multi-objective function is constructed with the objectives of minimizing the acceleration difference between the vehicle's acceleration and the target acceleration, and minimizing the yaw rate difference between the vehicle's yaw rate and the target yaw rate.

[0021] One possible implementation is that the mapping relationship between the target yaw rate and target acceleration, and the target regenerative braking force, target steering angle, and target suspension action force is determined based on the vehicle dynamics model.

[0022] One possible implementation involves the control module specifically used to: generate multiple combinations based on different regenerative braking forces, different steering angles, and different suspension dynamics, and determine the vehicle acceleration and yaw rate corresponding to each combination. Based on the target acceleration, target yaw rate, and the vehicle acceleration and yaw rate corresponding to each combination, calculate the objective function value of the multi-objective function corresponding to each combination. The combination with the smallest objective function value among the multiple combinations is determined as the target regenerative braking force, target steering angle, and target suspension dynamics. The objective function value is a weighted sum of the acceleration difference between the vehicle acceleration and the target acceleration, and the yaw rate difference between the vehicle yaw rate and the target yaw rate.

[0023] One possible implementation involves determining the required braking force based on the vehicle's brake pedal opening and speed. Specifically, the control module described above is used to: determine the target acceleration based on the brake pedal opening and vehicle speed using an acceleration mapping table. This acceleration mapping table includes the mapping relationship between brake pedal opening, vehicle speed, and the target acceleration.

[0024] One possible implementation involves driving state parameters including: vehicle wheelbase, mass, vehicle speed, wheel lateral stiffness, and front wheel steering angle.

[0025] In one possible implementation, the aforementioned control module is also used to: coordinately control the vehicle based on steering control and suspension control when the vehicle is in the target state and regenerative braking control fails.

[0026] In one possible implementation, the aforementioned control module is also used to: perform coordinated control of the vehicle based on EBM and regenerative braking control when the EBM malfunctions but the braking force that the EBM can provide is higher than a preset braking force threshold.

[0027] Thirdly, this application provides a vehicle. The vehicle includes the vehicle control device in any embodiment of the second aspect described above, or the vehicle is controlled by applying the vehicle control method in any embodiment of the first aspect described above.

[0028] Fourthly, this application provides a computer-readable storage medium storing at least one computer program, which is loaded and executed by a processor to implement the vehicle control method in any of the embodiments of the first aspect described above.

[0029] Fifthly, this application provides a computer program product, which includes a computer program or instructions that, when executed by a processor, implement the vehicle control method in any of the embodiments of the first aspect described above.

[0030] The solutions provided in the third to fifth aspects above can realize the vehicle control method in any embodiment of the first aspect above, and their specific implementations will not be described in detail here. The technical effects corresponding to any implementation of the solutions provided in the third to fifth aspects above can be found in the technical effects corresponding to any implementation of the first aspect above, and will not be described in detail here.

[0031] It should be noted that any of the possible implementations of any of the above aspects can be combined, provided that the solutions do not contradict each other. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application will be described below.

[0033] Figure 1 This is a schematic diagram of the structure of a braking control device disclosed in an embodiment of this application; Figure 2 This is a schematic flowchart of a vehicle control method disclosed in an embodiment of this application; Figure 3 This is a schematic diagram of a VMC control architecture disclosed in an embodiment of this application; Figure 4 This is a schematic diagram of an MPC-optimized architecture disclosed in an embodiment of this application; Figure 5 This is a schematic flowchart of another vehicle control method disclosed in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a vehicle control device disclosed in an embodiment of this application.

[0034] Explanation of reference numerals in the attached figures: 100 - Controller; 200 - Actuator. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0036] It should be noted that the terms "first," "second," etc., used 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 data 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 herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0037] In the embodiments of this application, the words "exemplary," "for example," or "e.g.," are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "e.g.," in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the words "exemplary," "for example," or "e.g.," is intended to present the relevant concepts in a specific manner.

[0038] The embodiments of this application are described below with reference to the accompanying drawings.

[0039] This application provides a vehicle.

[0040] Alternatively, a vehicle may also be referred to as a vehicle, mobile carrier, electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), fuel cell vehicle (FCV), autonomous vehicle, intelligent and connected vehicle (ICV), driverless vehicle, new energy vehicle, etc.

[0041] In this application's embodiments, the vehicle can be a sedan, a sport utility vehicle (SUV), a truck, an electric vehicle, a motorcycle, a tricycle, a special vehicle (such as an ambulance, fire truck, police car, etc.), a driverless taxi, an intelligent connected bus, an autonomous logistics vehicle, an electric truck, etc. The method provided in this application's embodiments is also applicable to various special-purpose vehicles, such as agricultural vehicles, mining vehicles, forestry vehicles, airport vehicles, port vehicles, etc., and this application does not impose specific limitations on them. For example, the vehicle can be an electric sport utility vehicle (SUV) including a hub motor, kingpin steering, fully active air suspension, and EMB.

[0042] In some embodiments, the vehicle includes a braking control device. The braking control device is a device that controls the deceleration, stopping, or bringing the vehicle to a standstill, and controls the distribution and adjustment of braking force.

[0043] For example, please refer to Figure 1 , Figure 1 This is a schematic diagram of a braking control device provided in an embodiment of this application. The braking control device provided in this embodiment includes a controller 100 and an actuator 200. The controller 100 is used to acquire driver operation commands (such as pedal opening signals and steering wheel angle signals), vehicle driving state parameters (such as vehicle speed, vehicle steering angle, and vehicle yaw rate), and environmental state parameters (such as road surface adhesion, speed limit information, and obstacle information). It is also used to control the actuator 200 based on the driver's operation commands, vehicle driving state parameters, and environmental state parameters to achieve vehicle braking control. For example, the controller 100 controls the brake calipers and brake pads to generate friction based on the brake pedal opening, thereby decelerating the vehicle.

[0044] Optionally, braking methods include anti-lock braking, electronic parking brake, regenerative braking, and stability braking (which corrects understeer or oversteer by applying braking force to one or more wheels to prevent skidding and loss of control). The controller 100 includes a vehicle motion control (VMC) controller, an anti-lock braking system (ABS) controller, an electronic brake force distribution controller, a traction control system controller (which reduces engine torque or applies braking to slipping wheels to prevent drive wheel slippage during vehicle start-up and acceleration), an electronic stability control (ESC) controller, and a regenerative braking controller. The VMC, as the central decision-making unit of the dual-core lockstep processor, possesses real-time bus communication (a controller area network with flexible data-rate (CAN FD) / vehicle Ethernet) and high computing power.

[0045] For example, the controller 100 acquires driver operating commands, driving state parameters, and environmental state parameters through multi-source sensors. Optionally, the sensors include a yaw rate sensor, four-wheel wheel speed sensors, an inertial measurement unit (IMU), a brake pedal, a suspension height sensor, an acceleration sensor, an angle sensor, and a steering wheel angle sensor.

[0046] Actuator 200 is used to perform braking actions according to the instructions of controller 100. For example, in regenerative braking control, actuator 200 is the vehicle's drive motor. The regenerative braking controller controls the drive motor to switch to generator mode, so that the electromagnetic resistance (reverse torque) generated by the drive motor acts on the wheels to achieve braking. Optionally, actuator 200 includes solenoid valves, vacuum boosters, motors, retarders, hub motors, kingpin steering, active suspension (such as continuous damping control (CDC) or fully active control), and EMB, etc.

[0047] In some embodiments, vehicle braking control is achieved via an EMB (Electronic Braking Machine). EMB is a brake-by-wire method that eliminates the need for hydraulic braking structures such as brake fluid and hydraulic lines. Exemplarily, the EMB installs a brake actuator directly driven by an electric motor on each wheel of the vehicle, using electrical signals and energy to achieve the braking control process. For example, the electronic control unit calculates the target braking force based on signals from the brake pedal travel sensor and wheel speed sensor, and then drives the EMB's actuator motor via a microcontroller unit (MCU) to actuate the ball screw to clamp the brake disc, thus achieving braking.

[0048] Compared to electronic hydraulic brakes (EHB), EMB offers faster response, simpler structure, and easier integration. However, EMB relies on electronic control signals, and its braking capability may be completely lost in the event of a failure such as controller malfunction, communication interruption, power failure, or motor jamming. To address braking control issues after EMB failure, backup EMBs and redundant braking devices are used. However, the redistribution of braking force after EMB failure can easily lead to vehicle instability and energy waste due to uneven force distribution. For example, simulation data shows that the probability of a vehicle veering off course after the failure of a single EMB on a slippery road surface is as high as 62%.

[0049] Based on this, embodiments of this application provide a vehicle control method capable of coordinating multiple backup braking modes to achieve braking control while ensuring vehicle driving stability. This method can be applied to the braking control device described above, or to other devices capable of performing braking functions. For example, please refer to... Figure 2 The vehicle control method provided in this application includes: Step S201: The braking control device determines whether the vehicle is in the target state.

[0050] The target state is one in which the vehicle's EMB cannot provide braking force.

[0051] Optionally, in the event of failure of the EMB's main controller, failure of the main power supply, or widespread communication interruption, the EMB is completely unable to provide braking force, and the vehicle is in the target state; or, if the braking force provided by the EMB is lower than the preset braking force threshold, it is determined that the vehicle is in the target state, and it is necessary to trigger the limp mode (fail-safe mode) or the backup braking control mode.

[0052] Limp mode is a mode that actively limits the vehicle's power performance, speed, and some functions (such as ABS and ESC) to provide minimum mobility in the event of a malfunction. Optionally, alternative braking control methods include regenerative braking control, mechanical braking control (such as spring- or solenoid-driven mechanical locking structures), etc.

[0053] For example, by using VMC to monitor the status of the EMB controller, communication signals, actuator feedback current / position, and the consistency of sensor data in real time, the failure or fault of the EMB can be diagnosed in real time, and the vehicle can be determined to be in the target state when the EMB cannot provide braking force.

[0054] Step S202: When the vehicle is in the target state, the braking control device performs coordinated control of the vehicle based on regenerative braking control, steering control and suspension control.

[0055] Regenerative braking control refers to sending control commands to the vehicle's drive motor during braking, causing the drive motor to switch from driving mode to power generation mode. In this mode, the drive motor acts as a generator. In power generation mode, the rotor of the drive motor connected to the wheel rotates in a magnetic field and generates electromagnetic resistance (regenerative braking force). The electromagnetic resistance acts on the wheel to slow down the vehicle, and at the same time, the kinetic energy of the wheel is converted into electrical energy and stored in the vehicle's power battery.

[0056] For example, the motor controller inputs current into the stator windings of the drive motor to generate a magnetic field. When the wheel drives the rotor to rotate in the magnetic field generated by the stator windings, it cuts the magnetic field lines, thereby inducing a current in the stator windings. The magnetic field generated by the induced current interacts with the rotor's magnetic field, producing an electromagnetic resistance that acts on the wheel, causing the vehicle to brake and decelerate. The motor controller can adjust the current in the stator windings by adjusting the amplitude and phase of the voltage applied to the drive motor, thereby regulating the magnitude of the regenerative braking force generated during regenerative braking.

[0057] As an example, in a scenario where a vehicle is traveling at 100 km / h on a slippery road, and the left front wheel EMB suddenly fails due to a motor driver malfunction (braking force drops to 0), while the other three wheel EMBs are functioning normally, the Vehicle Control Center (VMC) determines that the left front wheel EMB has failed based on the EMB controller status code (fault indicator) and abnormal feedback information from the left front wheel braking force (braking force less than 90% of the commanded braking force). The vehicle's instrument panel displays a "Brake System Degraded" warning. The VMC limits the drive torque of the left front wheel motor, rendering regenerative braking unavailable, and controls the right front wheel motor to output maximum regenerative braking force. At this point, limited by a battery SOC of 80%, the right front wheel motor can provide a maximum deceleration of 0.2g. Simultaneously, based on the driver's brake pedal opening, the VMC determines the deceleration requirement to be 0.5g. Therefore, the two rear wheel motors need to provide 0.3g of regenerative braking force (e.g., 0.15g per wheel). Additionally, since the left front wheel has no friction braking, the VMC adds extra braking force to the left rear wheel EMB (e.g., an additional 0.1g) to prevent brake deviation.

[0058] Steering control refers to controlling the wheel steering angles of a vehicle to improve its driving stability and, in conjunction with regenerative braking control, enhance braking performance. For example, in the event of a skid, electronic power steering (EPS) can fine-tune steering assist or apply counter-compensating torque to help the driver regain control. Another example is the use of a kingpin steering system to output a compensating steering angle, using yaw moment to assist in vehicle stability.

[0059] For example, by using VMC to estimate vehicle instability risk in real time (yaw rate deviation or center of gravity sideslip angle exceeding a preset instability threshold), when the vehicle is detected to be in a state of braking pull, fishtailing, or understeer, the vehicle's rear wheel steering angle (or four-wheel steering) is actively controlled to generate a counter-yawing torque to counteract the rotational trend and compensate for understeer. When the vehicle exhibits an oversteer tendency, the rear wheels are controlled to rotate in the same direction as the front wheels; when the vehicle exhibits an understeer tendency, the rear wheels are controlled to rotate in the opposite direction to the front wheels. As an example, in a scenario where the vehicle is traveling at 100 km / h on a slippery road, and the left front wheel EMB suddenly fails due to a motor driver malfunction (braking force drops to 0), while the other three wheel EMBs are normal, the IMU detects that the vehicle is yawing to the left (yaw rate deviation > 3° / s), indicating a fishtailing risk. At this time, the VMC controls the rear wheels to rotate 1.5° to the right (opposite to the front wheels), generating a counter-clockwise yawing torque to counteract the left-turning tendency. The steering angle is adjusted in real time according to the deviation (e.g., PID control, where the proportional gain Kp = 0.8).

[0060] Suspension control refers to adjusting the suspension parameters of a vehicle to control the magnitude of the suspension forces, thereby improving vehicle stability and enhancing braking performance in conjunction with regenerative braking control and / or steering braking control. For example, adjusting the suspension parameters of an active suspension alters the load distribution between the wheels, improving the utilization rate of friction braking force.

[0061] Among them, suspension action refers to the interaction force generated inside the suspension and between the suspension and the vehicle body and wheels during vehicle operation.

[0062] For example, the power exerted by the suspension includes elastic force, damping force, and guiding force. Elastic force is provided by the suspension's elastic elements (such as coil springs, torsion bar springs, and air springs). When the wheel encounters a bump in the road, the elastic element is compressed or stretched, and the resulting elastic restoring force offsets part of the impact, preventing vibration from being directly transmitted to the vehicle body. Damping force is provided by the suspension's shock absorbers (dampers), used to suppress the reciprocating vibration of the elastic elements. When the suspension compresses or rebounds, the fluid in the shock absorber passes through damping orifices, generating resistance in the opposite direction of motion, quickly attenuating the vibration amplitude of the vehicle body. Guiding force is transmitted by the suspension's guiding structures (such as control arms, linkages, and steering knuckles), used to constrain the wheel's trajectory, while simultaneously transmitting the wheel's longitudinal forces (driving force, braking force) and lateral forces (lateral forces during steering), preventing excessive wheel deviation.

[0063] For example, by adjusting the damping / stiffness of the active suspension through VMC, braking dive and body roll can be suppressed. This includes increasing the stiffness of the front suspension and decreasing the stiffness of the rear suspension to maintain tire contact load. The load on wheels with insufficient braking force (such as those with failed EMB) can be increased (e.g., by raising the suspension or increasing damping) to improve the friction braking force of these wheels. During vehicle cornering, the outer suspension support can be strengthened to maintain tire grip. As an example, in a scenario where a vehicle is traveling at 100 km / h on a slippery road, and the left front wheel EMB suddenly fails due to a motor driver malfunction (braking force drops to 0), while the EMBs of the other three wheels are normal, the left front suspension height can be increased (+10mm) and the damping force increased (+30%) to increase the vertical load on the left front wheel and maximize its friction. The right front suspension height can be lowered (-5mm) to balance the vehicle's pitch angle and suppress braking dive. Additionally, the stiffness of the left rear suspension can be increased (to prevent increased body roll due to steering compensation).

[0064] As an example, such as Figure 3As shown, the VMC acquires the driver's operation command 300 and the driving status parameters monitored by the sensor 305 and the failure signal of the EMB, etc., and determines the target regenerative braking force, target steering angle and target suspension power. Based on the target regenerative braking force, target steering angle and target suspension power, the VMC controls the hub motor 301, active suspension 302 and kingpin steering 303 to provide braking force and maintain vehicle stability. At the same time, it controls the EMB, which can also provide braking force, to brake, thereby realizing the coordinated control of regenerative braking control, steering control, suspension control and EBM.

[0065] In some embodiments, the required braking force and driving state parameters of the vehicle are determined. Based on the driving state parameters, with the goal of the vehicle providing the required braking force and the driving stability reaching a driving stability threshold, the regenerative braking force, steering angle, and suspension action are optimized to obtain the target regenerative braking force, target steering angle, and target suspension action. Then, the vehicle is coordinated and controlled based on the target regenerative braking force, target steering angle, and target suspension action.

[0066] Demand braking force refers to the total braking force that the braking control equipment needs to provide to achieve the desired deceleration of the vehicle as intended by the driver. For example, a pedal travel sensor detects the brake pedal opening; the deeper the brake pedal is pressed by the driver, the greater the demand braking force. Specifically, the demand braking force can be mapped from the brake pedal opening to a preset pedal feel curve. Another example is when an impending collision is detected; the demand braking force is the maximum braking force that the braking control equipment can provide to avoid a collision.

[0067] The stability threshold value is either a default value or a manually set value, reflecting the degree of vehicle stability. For example, vehicle stability is characterized by the vehicle's yaw rate, in which case the stability threshold value is a preset yaw rate value.

[0068] As an example, the required braking force is characterized by target acceleration, which is determined based on the vehicle's brake pedal opening and vehicle speed.

[0069] For example, the brake pedal opening signal (0-100%) and vehicle speed signal are collected, and the target acceleration is determined in the acceleration mapping table based on the brake pedal opening signal and vehicle speed signal.

[0070] The acceleration mapping table includes the mapping relationship between brake pedal opening, vehicle speed, and target acceleration. This mapping relationship can be flexibly adjusted according to specific application needs. For example, the curve trend of the relationship between brake pedal opening and target acceleration is relatively gentle at the beginning (to provide a comfortable and smooth braking feel), linear in the middle (target acceleration is proportional to brake pedal opening), and steep at the end (to provide strong braking force when the driver presses the pedal deeply, meeting emergency braking needs). The relationship curve between brake pedal opening and target acceleration differs at different vehicle speeds.

[0071] Optionally, driving parameters include the vehicle's wheelbase, mass, speed, wheel lateral stiffness, and front wheel steering angle.

[0072] As an example, the target yaw rate at which the vehicle's driving stability reaches the driving stability threshold is determined based on driving state parameters. Based on the target acceleration and target yaw rate, the regenerative braking force, steering angle, and suspension action are optimized to obtain the target regenerative braking force, target steering angle, and target suspension action.

[0073] For example, the formula for calculating the target yaw rate can be expressed as:

[0074]

[0075] in, Indicates the target's yaw rate. Indicates the vehicle's longitudinal speed. Indicates the front wheel steering angle. K represents the wheelbase, K represents the stability factor, and m represents the mass. This indicates the lateral stiffness of the rear wheel. This indicates the lateral stiffness of the front wheel. This indicates the distance between the vehicle's center of gravity and the front axle. This indicates the distance between the vehicle's center of gravity and the rear axle.

[0076] For example, the target regenerative braking force, target steering angle, and target suspension action force are solved based on a pre-constructed multi-objective function.

[0077] Among them, the multi-objective function is constructed with the objectives of minimizing the acceleration difference between the vehicle acceleration and the target acceleration, and minimizing the yaw rate difference between the vehicle yaw rate and the target yaw rate.

[0078] For example, based on a pre-built multi-objective function, the target regenerative braking force, target steering angle, and target suspension action force are solved, including the following steps: Step 1: Generate multiple combinations based on different regenerative braking forces, different steering angles, and different suspension forces.

[0079] Step 2: Determine the vehicle acceleration and yaw rate for each combination.

[0080] For example, the mapping relationship between yaw rate and acceleration and regenerative braking force, steering angle and suspension action is determined based on the vehicle dynamics model. The regenerative braking force, steering angle and suspension action are input into the vehicle dynamics model, and the vehicle acceleration and yaw rate corresponding to the regenerative braking force, steering angle and suspension action are output by the vehicle dynamics model.

[0081] Among them, the vehicle dynamics model is a mathematical and physical model that describes, analyzes, and predicts the motion state of a vehicle under the action of forces.

[0082] For example, a vehicle dynamics model includes a dynamics model and a tire model (such as a tire model that integrates 3-DOF vehicle dynamics with the magic formula). The dynamics model is established in the coordinate system of the vehicle's center of mass. The state variables of the dynamics model include the vehicle's longitudinal speed, lateral speed, longitudinal acceleration, lateral acceleration, and yaw rate. Control variables include regenerative braking force, rear wheel steering angle, and suspension action. Model parameters include the vehicle's mass (kg·m²), vehicle moment of inertia (kg·m²), distance from the vehicle's center of mass to the front axle (m), distance from the vehicle's center of mass to the rear axle (m), half the front wheel track width (m), half the rear wheel track width (m), and gravitational acceleration (m / s²).

[0083] Specifically, the longitudinal motion of the vehicle in the dynamic model can be expressed by the following formula:

[0084]

[0085]

[0086] Where m represents the total vehicle mass. This represents the longitudinal acceleration of the vehicle. Indicates the lateral speed of the vehicle. Indicates the longitudinal speed of the vehicle. Indicates yaw rate. Indicates the vehicle's number The longitudinal force of each wheel This represents the lateral force on the i-th wheel of the vehicle. and It was calculated from a tire model. Indicates the wheel steering angle. Indicates air resistance, Indicates rolling resistance, Indicates the air drag coefficient. Indicates the windward area. Let g represent air density and g represent gravitational acceleration. This represents the rolling resistance coefficient.

[0087] The lateral motion of a vehicle can be expressed by the following formula:

[0088] Where m represents the total vehicle mass. This indicates the lateral acceleration of the vehicle. Indicates yaw rate. Indicates the vehicle's number The longitudinal force of each wheel This represents the lateral force on the i-th wheel of the vehicle. This indicates the wheel steering angle.

[0089] The yaw motion of a vehicle can be expressed by the following formula:

[0090] in, This represents the total yaw moment generated by the wheels of a vehicle about its center of gravity. Indicates the moment of inertia. It represents the yaw acceleration.

[0091] The vertical load of a vehicle can be expressed by the following formula:

[0092]

[0093] in, The value represents the static load on the left front wheel of the vehicle, m represents the total vehicle mass, and g represents the acceleration due to gravity. This indicates the distance between the vehicle's center of gravity and the front axle. This indicates the distance between the vehicle's center of gravity and the rear axle. This indicates the dynamic load on the vehicle's left front wheel. The vector represents the longitudinal acceleration of the vehicle, and h represents the height of the vehicle's center of gravity. This indicates the lateral acceleration of the vehicle. This indicates half the track width of the vehicle's front wheels. This indicates that the suspension is the power source.

[0094] Step 3: Based on the target acceleration, target yaw rate, and the vehicle acceleration and yaw rate corresponding to each combination, calculate the objective function value of the multi-objective function corresponding to each combination.

[0095] The objective function value is a weighted sum of the acceleration difference between the vehicle's acceleration and the target acceleration, and the yaw rate difference between the vehicle's yaw rate and the target yaw rate.

[0096] For example, the formula for calculating the objective function value can be expressed as:

[0097] in, Represents the objective function value. This represents the weight corresponding to the target acceleration. This represents the weight corresponding to the target's yaw rate. This represents the corresponding target acceleration. Indicates the target's yaw rate. Indicates vehicle acceleration. This represents the yaw rate of the vehicle, where i represents time. This represents the duration in the time domain, where n is typically 10-50 ms.

[0098] Optionally, and The value can be the default value, a preset value, or a value that is adjusted in real time according to the vehicle's environment.

[0099] For example, the severity of vehicle EBM failure and the road adhesion coefficient of the road surface on which the vehicle is located are used to... and Adjustments need to be made. For example, when the road surface adhesion coefficient is less than 0.3 (low-adhesion road surface) or the EMB cannot provide braking force, Stability is the priority; when the road surface adhesion coefficient is greater than 0.75 (high adhesion road surface) or there is a single point of failure (such as the failure of one of multiple EMBs), Prioritize braking performance (minimize braking distance).

[0100] Step 4: Determine the regenerative braking force, steering angle, and suspension power corresponding to the combination with the smallest objective function value among multiple combinations as the target regenerative braking force, target steering angle, and target suspension power.

[0101] In some embodiments, after the target regenerative braking force is determined, the regenerative torque of each motor of the vehicle is dynamically allocated according to the target regenerative braking force, or the target regenerative braking force corresponding to each of the multiple motors is directly determined by a multi-objective function.

[0102] In some embodiments, a model predictive control (MPC) controller is used to optimize the solution of a multi-objective function. For example, the MPC controller performs the following steps within each preset control cycle (e.g., 10ms): Step 01: Collect sensor signals to obtain driving status parameters such as wheel speed, center of gravity sideslip angle, yaw angle, longitudinal acceleration, and lateral acceleration.

[0103] Step 02: Update the vehicle dynamics model based on the vehicle's current state (such as driving state parameters).

[0104] Step 03: Within the preset prediction and control time, optimize and solve the multi-objective function using the vehicle dynamics model to obtain the target regenerative braking force, target steering angle, and target suspension action force.

[0105] Step 04: Send the target regenerative braking force, target steering angle, and target suspension power to the actuator for execution.

[0106] Step 05: The MPC controller enters the next control cycle and repeats steps 01-04.

[0107] For example, such as Figure 4 As shown, the MPC receives driver operation commands 300 and vehicle feedback driving status parameters, determines the target regenerative braking force, target steering angle, and target suspension power, and then distributes the regenerative torque of each wheel hub motor 301 based on the target regenerative braking force to control the regenerative torque of the wheel hub motor 301. At the same time, the kingpin steering 303 performs steering control based on the target steering angle, and the active suspension 302 performs suspension control based on the target suspension power. The vehicle responds to regenerative braking control, steering control, and suspension control, and at the same time feeds back driving status parameters to the MPC.

[0108] In some embodiments, when optimizing the multi-objective function, the regenerative braking force, steering angle, and suspension action force need to meet constraints. For example, the constraints include: the regenerative braking force is less than or equal to the maximum regenerative braking force allowed by the braking control device or the vehicle (the maximum regenerative braking force can be calculated based on the maximum charging power of the vehicle battery, vehicle speed, etc.), the rear wheel steering angle is less than or equal to a preset steering angle value (the preset steering angle value can be obtained by looking up a table based on vehicle speed), and the suspension action force is less than or equal to the peak thrust of the motor (the peak thrust of the motor can be determined based on the characteristic parameters of the motor (such as peak torque, transmission ratio)).

[0109] In some embodiments, when the vehicle is in a target state and regenerative braking control fails, the vehicle is controlled collaboratively based on steering control and suspension control. For example, in the event of a complete failure of the vehicle's EMB and the unavailability of regenerative braking, the VMC utilizes kingpin steering and active suspension to collaboratively control the vehicle and maintain vehicle stability.

[0110] In some embodiments, when the braking force provided by regenerative braking control is lower than a preset regenerative braking force threshold, the driving torque of the vehicle is limited to prevent the drive wheels from slipping.

[0111] In some embodiments, when an EBM fails but the braking force it can provide exceeds a preset braking force threshold, the vehicle is controlled collaboratively based on the EBM and regenerative braking control. For example, in the event of a single EBM failure among multiple EBMs in the vehicle, the VMC activates the other EBMs for braking, while simultaneously using the in-wheel motors for regenerative braking control to maintain a near-normal braking effect. Specifically, the VMC calculates the regenerative braking force, dynamically distributes the regenerative torque of each motor in the vehicle, and issues commands to control the in-wheel motors to output regenerative braking force. The maximum regenerative braking force of each in-wheel motor can be determined based on the battery state of charge (SOC) / temperature limit. The braking force provided by regenerative braking, combined with the braking force provided by the unfailed EBMs, is compensated for through torque vector control, achieving collaborative control of regenerative braking and EBMs.

[0112] In some embodiments, an alarm is triggered when the EBM is abnormal (such as the fluctuation range of operating parameters such as current and temperature of the EBM becomes larger), and some vehicle performance is limited (such as reducing the proportion of regenerative braking and controlling the EBM to provide more braking force compensation).

[0113] In some embodiments, VMC diagnoses single-point or multi-point failures in the EMB system by real-time monitoring of the EMB controller's status, communication signals, actuator feedback current / position, and the consistency of sensor data.

[0114] In some embodiments, different braking control strategies are executed by monitoring the degree of EMB failure (failure level). For example, such as... Figure 5 As shown, this application provides a schematic flowchart of another vehicle control method, which includes: Step S501: Begin.

[0115] Step S502: EMB failure monitoring.

[0116] For example, in the event of an EBM malfunction (such as an increase in the fluctuation range of operating parameters of the EBM, such as current and temperature), step S503 is executed; in the event of a single EBM failure among multiple EBMs in the vehicle, step S504 is executed; in the event of the vehicle being in the target state, step S505 is executed; and in the event of the vehicle being in the target state and a regenerative braking control failure, step S506 is executed.

[0117] Step S503: Alarm notification.

[0118] Step S504: Activate the EMB that can provide braking force for braking, and simultaneously perform coordinated control through regenerative braking, steering braking and suspension control.

[0119] Step S505: Coordinated control is achieved through regenerative braking, steering braking, and suspension control.

[0120] Step S506: Coordinated control is achieved through steering braking and suspension control.

[0121] Step S507: Calculate the required braking force and perform stability risk detection.

[0122] For example, the risk of vehicle instability can be measured based on factors such as vehicle yaw rate and steering angle.

[0123] Step S508: Determine the target regenerative braking force, target steering angle, and target suspension action force through a multi-objective function.

[0124] Step S509: Output control command.

[0125] For example, control commands are sent to the hub motor, kingpin steering, and active suspension based on the target regenerative braking force, target steering angle, and target suspension action force, respectively.

[0126] Step S510: Monitor the vehicle status. If EMB is restored or the vehicle is stopped, exit the backup mode; otherwise, proceed to step S507.

[0127] This application also provides a vehicle control device; please refer to [link / reference]. Figure 6 The vehicle control device provided in this application includes a processing module 601 and a control module 602. The processing module 601 is used to execute... Figure 2 In the illustrated method, step S201 is executed by the control module 602. Figure 2 The illustrated method includes step S202.

[0128] The foregoing mainly describes the solutions provided by the embodiments of this application from the perspective of methods and apparatus. To achieve the above functions, the vehicle control device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can 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.

[0129] This application embodiment can, based on the above-described vehicle control method, exemplarily divide the vehicle control device into functional modules. For example, the vehicle control device may include functional modules corresponding to each functional division, or two or more functions may be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division; in actual implementation, there may be other division methods.

[0130] This application also provides a computer-readable storage medium storing at least one computer program, which is loaded and executed by a processor to implement the vehicle control processing method provided in the above-described method embodiments.

[0131] 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), magnetic tape, floppy disk, and optical data storage device.

[0132] This application also provides a computer program product, which includes a computer program or instructions. When the computer program or instructions are executed by a processor, they implement the vehicle control method provided in the above-described method embodiments.

[0133] 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 a computing device, they implement the various processes of the above-described method embodiments and achieve the same technical effects as the above-described methods. To avoid repetition, they will not be described again here.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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 solutions of the embodiments of this application, essentially, or the parts that contribute to the prior art, or all or part of the technical solutions, 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.

[0138] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this application still fall within the scope of this application.

Claims

1. A vehicle control method, characterized in that, The vehicle control method includes: Determine whether the vehicle is in a target state; wherein, the target state is a state in which the vehicle's electromechanical braking (EMB) cannot provide braking force; When the vehicle is in the target state, the vehicle is controlled in a coordinated manner based on regenerative braking control, steering control, and suspension control.

2. The vehicle control method according to claim 1, characterized in that, The coordinated control of the vehicle based on regenerative braking control, steering control, and suspension control includes: Determine the required braking force and driving state parameters of the vehicle; Based on the driving state parameters, with the goal of the vehicle providing the required braking force and the driving stability reaching the driving stability threshold, the regenerative braking force of the regenerative braking control, the steering angle of the steering control, and the suspension action force of the suspension control are optimized and solved to obtain the target regenerative braking force, the target steering angle, and the target suspension action force. The vehicle is controlled in a coordinated manner based on the target regenerative braking force, the target steering angle, and the target suspension force.

3. The vehicle control method according to claim 2, characterized in that, Based on the driving state parameters, and with the goal of the vehicle providing the required braking force and achieving a driving stability threshold, the regenerative braking force of the regenerative braking control, the steering angle of the steering control, and the suspension action force of the suspension control are optimized and solved to obtain the target regenerative braking force, target steering angle, and target suspension action force, including: The target acceleration is determined based on the required braking force. Based on the driving state parameters, determine the target yaw rate when the vehicle's driving stability reaches the driving stability threshold value; Based on the target acceleration and the target yaw rate, the regenerative braking force of the regenerative braking control, the steering angle of the steering control, and the suspension action force of the suspension control are optimized and solved to obtain the target regenerative braking force, the target steering angle, and the target suspension action force.

4. The vehicle control method according to claim 3, characterized in that, The optimization solution based on the target acceleration and the target yaw rate, for the regenerative braking force of the regenerative braking control, the steering angle of the steering control, and the suspension action of the suspension control, to obtain the target regenerative braking force, the target steering angle, and the target suspension action, includes: Based on a pre-constructed multi-objective function, the target regenerative braking force, the target steering angle, and the target suspension action force are solved. The multi-objective function is constructed with the objectives of minimizing the acceleration difference between the vehicle acceleration and the target acceleration, and minimizing the yaw rate difference between the vehicle yaw rate and the target yaw rate.

5. The vehicle control method according to claim 4, characterized in that, The mapping relationship between the target yaw rate and the target acceleration, and the target regenerative braking force, the target steering angle, and the target suspension action force is determined based on the vehicle dynamics model.

6. The vehicle control method according to claim 4, characterized in that, The process of solving for the target regenerative braking force, the target steering angle, and the target suspension braking force based on a pre-constructed multi-objective function includes: Multiple combinations are generated based on different regenerative braking forces, different steering angles, and different suspension forces. Determine the vehicle acceleration and vehicle yaw rate for each of the aforementioned combinations; Based on the target acceleration, the target yaw rate, and the vehicle acceleration and vehicle yaw rate corresponding to each combination, the objective function value of the multi-objective function corresponding to each combination is calculated; wherein, the objective function value is: the weighted sum of the acceleration difference between the vehicle acceleration and the target acceleration and the yaw rate difference between the vehicle yaw rate and the target yaw rate; The regenerative braking force, steering angle, and suspension power corresponding to the combination with the smallest objective function value among the multiple combinations are determined as the target regenerative braking force, the target steering angle, and the target suspension power.

7. The vehicle control method according to claim 3, characterized in that, The required braking force is determined based on the vehicle's brake pedal opening and vehicle speed. Determining the target acceleration based on the required braking force includes: Based on the brake pedal opening and the vehicle speed, the target acceleration is determined in an acceleration mapping table; wherein, the acceleration mapping table includes the mapping relationship between the brake pedal opening, the vehicle speed and the target acceleration.

8. The vehicle control method according to claim 3, characterized in that, The driving status parameters include: the vehicle's wheelbase, mass, speed, wheel lateral stiffness, and front wheel steering angle.

9. The vehicle control method according to claim 1, characterized in that, The vehicle control method further includes: When the vehicle is in the target state and the regenerative braking control fails, the vehicle is controlled in a coordinated manner based on the steering control and the suspension control.

10. The vehicle control method according to claim 1, characterized in that, The vehicle control method further includes: If the EBM malfunctions, but the braking force provided by the EBM is higher than a preset braking force threshold, the vehicle is controlled in a coordinated manner based on the EBM and the regenerative braking control.

11. A vehicle control device, characterized in that, include: The processing module is used to determine whether the vehicle is in a target state; wherein, the target state is a state in which the vehicle's electromechanical braking (EMB) cannot provide braking force; A control module is used to coordinate the control of the vehicle based on regenerative braking control, steering control, and suspension control when the vehicle is in the target state.

12. A vehicle, characterized in that, Includes the vehicle control device as described in claim 11.

Images