Vehicle steering control method based on EMB system

Abstract

The invention discloses a vehicle steering control method based on an EMB system, and belongs to the technical field of EMB control systems.The vehicle steering control method comprises the steps that S1, it is guaranteed that the driving, braking and steering states of a vehicle are good, and a driver activates a function switch; s2, driving the vehicle by a driver and turning a steering wheel (turning left or turning right); s3, the driver steps on an accelerator, the system judges whether the accelerator opening degree exceeds a threshold value or not (or whether the driving torque exceeds the threshold value or not) at the moment, if yes, the step S4 is executed, and if not, braking force is applied to inner side wheels through a braking system, and the vehicle is in the static state; and S4, front wheels of the vehicle serve as driving wheels, a driver steps on an accelerator to apply driving force, wheels on the inner side of turning apply braking force through a braking system, rotating torque (namely yawing moment) is generated, and the turning radius of the vehicle is smaller than the general minimum turning radius. The four-wheel EMB system is controlled through a system software layer, the rotating torque is generated, the turning radius is reduced, hardware cost does not need to be increased, and vehicle hardware cannot be abraded.

Description

Technical Field

[0001] The present invention relates to the technical field of EMB control systems, and particularly to a vehicle steering control method based on an EMB system. Background Art

[0002] With the increasing electrification of vehicles, in order to pursue battery life and ride comfort, the body size has also become larger. In urban roads, especially narrow passages, the increase in body size means a reduction in vehicle passability. Since the minimum turning radius of a vehicle is fixed, and under the condition that the steering geometry and the basic vehicle dimensions are fixed, it cannot be reduced unless rear-wheel assist steering is installed. To address the passability problem of large-sized vehicles, many vehicle manufacturers have turned their attention to rear-wheel assist steering, which can effectively reduce the minimum turning radius and improve the passability in narrow roads. However, rear-wheel assist steering not only requires modification and update of the vehicle chassis, but also increases the vehicle manufacturing cost. Summary of the Invention

[0003] The purpose of the present invention is to provide a vehicle steering control method based on an EMB system to solve the above problems. By controlling the vehicle EMB system through system software, the minimum turning radius of the vehicle is reduced and the cost is reduced.

[0004] Technical Solution: The present invention provides a vehicle steering control method based on an EMB system, including: S1 Ensure that the vehicle driving, braking, and steering states are good, and the driver activates the function switch; S2 The driver drives the vehicle to turn the steering wheel all the way (left or right); S3 The driver steps on the accelerator, and the system determines whether the throttle opening at this time exceeds the threshold (or whether the driving torque exceeds the threshold). If so, enter S4; if not, apply a braking force to the inner wheels through the braking system to achieve a stationary state of the vehicle. S4 The front wheels of the vehicle are used as driving wheels, the driver steps on the accelerator to apply a driving force, and the inner wheels during turning apply a braking force through the braking system to generate a rotational torque (i.e., a yaw moment), so that the vehicle achieves a turning radius smaller than the normal minimum turning radius.

[0005] Further, in the above vehicle steering control method based on an EMB system, in S4, the braking forces of the front and rear wheels on the steering side are adjusted according to the turning direction. After the driving reaches the maximum torque, the braking force of the wheels on the steering side is reduced to achieve the target yaw angular velocity and ensure the rotation of the vehicle.

[0006] Further, in the above vehicle steering control method based on the EMB system, in S4, it is necessary to simultaneously monitor the wheel speeds of the two inner wheels. When the slip rate of a certain wheel tends to lock, its braking force is dynamically transferred to the other wheel to ensure that the wheels do not lock while satisfying the braking force of the inner wheels.

[0007] Further, in the above vehicle steering control method based on the EMB system, S4 further includes monitoring the turning radius, and judging the current turning radius according to the vehicle speed v and the yaw rate.

[0008] Further, in the above vehicle steering control method based on the EMB system, to judge the current turning radius, according to the following formula: V = yaw rate * R; where v: vehicle speed; yaw rate: yaw rate; R: turning radius.

[0009] Further, in the above vehicle steering control method based on the EMB system, S4 includes the following steps: S41 Regulate the braking forces of the front and rear wheels on the steering side of the vehicle; S42 Judge whether the wheels are locked. If not, enter step S3. If so, enter step S41 again.

[0010] A vehicle steering control system based on the EMB system includes the system structure of the vehicle. The system structure includes a central controller and a wheel-end controller EMB. The central controller is connected to the wheel-end controller EMB through bus communication.

[0011] From the above technical solutions, it can be seen that the present invention has the following beneficial effects: The vehicle steering control method based on the EMB system of the present invention controls the four-wheel EMB system at the system software level. The vehicle is front-wheel drive. The driver steps on the accelerator to apply driving force. The inner wheels during turning apply braking force through the quality control system to generate rotational torque, helping the vehicle reduce the minimum turning radius without increasing hardware costs, and the wheels do not lock or slip, and will not cause wear to the vehicle hardware. Description of the Drawings

[0012] Figure 1 It is a schematic diagram of a vehicle steering control method based on the EMB system of the present invention; Figure 2 It is a schematic diagram of the mechanics of the turning radius of the vehicle of the present invention. Detailed Embodiments Embodiment

[0013] As Figure 1 shown, a vehicle steering control method based on the EMB system includes: S1 Ensure that the driving, braking, and steering states of the vehicle are good, and the driver activates the function switch; S2 The driver turns the steering wheel hard (left or right) while driving the vehicle; S3 The driver steps on the accelerator, and the system determines whether the throttle opening at this time exceeds the threshold (or whether the driving torque exceeds the threshold). If so, it enters S4. If not, the braking system applies braking force to the inner wheels to achieve a state where the vehicle is stationary; S4 The front wheels of the vehicle are used as driving wheels. The driver steps on the accelerator to apply driving force, and the inner wheels during turning apply braking force through the braking system to generate a rotational torque (i.e., yaw moment), so that the vehicle reaches a turning radius smaller than the normal minimum turning radius.

[0014] In this embodiment, S3 needs to generate the maximum rotational torque to achieve a smaller turning radius, that is, the threshold of the throttle opening or driving torque is set to a balanced state where the wheels do not lock or slip when the wheels rotate stably and reach the maximum driving torque of the vehicle and the maximum braking force of the inner wheels; after the driving reaches the maximum torque, by reducing the braking force of the steering side wheels, the target yaw angular velocity is achieved to ensure vehicle rotation and prevent wear on the vehicle hardware.

[0015] In this embodiment, the wheel speeds of the two inner wheels also need to be monitored simultaneously in S4. When the slip rate of a certain wheel tends to lock, its braking force is dynamically transferred to the other wheel to ensure that the wheels do not lock while meeting the braking force of the inner wheels.

[0016] As Figure 2 shown, a vehicle steering control method based on the EMB system, S4 also includes monitoring the turning radius. According to the vehicle speed v and the yaw angular velocity yawrate, the current turning radius is judged, and the formula is V = yawrate * R; where v: vehicle speed; yawrate: yaw angular velocity; R: turning radius.

[0017] In this embodiment, the braking force of the inner wheels during turning is controlled in a closed loop by the yaw angular velocity yawrate. When the wheels tend to lock, the braking force of the front and rear inner wheels during turning is arbitrated and distributed.

[0018] In this embodiment, S4 includes the following steps: S41 Regulate the braking force of the front and rear wheels on the steering side of the vehicle; S42 Judge whether the wheels are locked. If not, enter step S3. If so, enter step S41 again.

[0019] In this embodiment, a vehicle steering control system based on the EMB system is also provided, including the system structure of the vehicle. The system structure includes a central controller and a wheel-end controller EMB, and the central controller is connected to the wheel-end controller EMB through bus communication.

[0020] It should be noted that the above description is only the technical solution of the invention rather than a limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solution of the invention can be modified or equivalently replaced without departing from the scope of the technical solution of the present invention, and all of them should be covered by the scope of the claims of the present invention.

Claims

1. A vehicle steering control method based on an EMB system, characterized in that: Including: S1 Ensure that the vehicle's driving, braking, and steering states are good, and the driver activates the function switch; S2 The driver drives the vehicle with the steering wheel turned all the way (left or right); S3 The driver steps on the accelerator, and the system determines whether the throttle opening at this time exceeds the threshold (or whether the driving torque exceeds the threshold). If so, enter S4; if not, apply braking force to the inner wheels through the braking system to achieve a stationary state of the vehicle; S4 With the vehicle's front wheels as the driving wheels, the driver steps on the accelerator to apply driving force, and the inner wheels of the turn apply braking force through the braking system to generate a rotational torque (i.e., yaw moment), enabling the vehicle to achieve a turning radius smaller than the normal minimum turning radius.

2. The vehicle steering control method based on the EMB system according to claim 1, characterized in that: In S4, the braking forces of the front and rear wheels on the steering side are regulated according to the turning direction. After the driving reaches the maximum torque, the braking force of the wheels on the steering side is reduced to achieve the target yaw angular velocity and ensure the rotation of the vehicle.

3. The vehicle steering control method based on the EMB system according to claim 2, wherein: In S4, it is necessary to simultaneously monitor the wheel speeds of the two inner wheels. When the slip rate of a certain wheel tends to lock, its braking force is dynamically transferred to the other wheel to ensure that the wheels do not lock while meeting the braking force of the inner wheels.

4. A vehicle steering control method based on an EMB system according to claim 1, characterized in that: S4 also includes monitoring the turning radius, and judging the current turning radius according to the vehicle speed v and the yaw angular velocity yawrate.

5. The vehicle steering control method based on the EMB system according to claim 4, characterized in that: Judge the current turning radius according to the following formula: V = yawrate * R Where v: vehicle speed; yawrate: yaw angular velocity; R: turning radius.

6. The vehicle steering control method based on the EMB system according to claim 1, characterized in that: In S3, the threshold of the throttle opening or driving torque is the maximum driving torque of the vehicle and the maximum braking force of the inner wheels in the balanced state where the wheels rotate stably without locking or slipping.

7. A vehicle steering control method based on an EMB system according to claim 1, characterized in that: S4 includes the following steps: S41 Regulate the braking forces of the front and rear wheels on the steering side of the vehicle; S42 Judge whether the wheels are locked. If not, enter step S3; if so, enter step S41 again.

8. A vehicle steering control system based on an EMB system, characterized in that: Including a central controller and a wheel-end controller EMB.

9. The vehicle steering control system based on the EMB system according to claim 8, wherein: The central controller is connected to the wheel-end controller EMB through bus communication.

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