Control method for automatically passing cross-country cross-axis working condition

Abstract

The invention provides a control method for automatically passing a cross-country cross-axis working condition, which comprises the following steps of: in response to a cross-axis mode opening request, judging whether an opening precondition of a cross-axis mode is met or not; if the starting precondition of the cross-axis mode is met, the vehicle is controlled to enter a cross-axis working condition to operate; when the vehicle runs in the cross-axle mode, the maximum torque of the wheel ends can be called, and meanwhile braking pressure is applied to the wheel ends; the vehicle speed is limited to be low; the height of the vehicle suspension is increased to the maximum; a rear axle differential lock is automatically locked; images around the vehicle body are collected through a camera and displayed to a user; and the torque of front and rear shafts is distributed by judging whether front wheels or rear wheels of the vehicle are in a slipping or idling state or not, and the braking pressurization speed and the braking pressure of the slipping or idling wheels are increased. The cross-country escape performance of the vehicle can be enhanced, and the vehicle use threshold of consumers is lowered.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and in particular to a control method for automatically passing an off-road cross-axle working condition. Background Art

[0002] As the technology of electric vehicles matures, consumers' demands for electric vehicles are becoming more and more diverse. Therefore, in addition to being able to meet the needs of conventional driving conditions, more and more users of electric and hybrid vehicles hope that the vehicles can meet the needs of off-road scenarios. When the vehicle reaches the position of the shell crater, one or any two diagonal wheels may lose grip (driving force), and the vehicle cannot continue to move forward. This condition is called the "cross-axle condition". However, traditional models do not have control strategies designed for cross-axle conditions. When encountering cross-axle conditions, the driver's driving experience is required to control the vehicle to get out of trouble. Conventional off-road creep logic often has large torque fluctuations when passing through the cross-axle, causing the vehicle speed to soar or come to a complete standstill. Therefore, it has become an urgent problem to develop off-road scene usage functions for cross-axle conditions, enhance the actual escape performance of the vehicle, and lower the threshold for consumer use. Summary of the invention

[0003] The purpose of the present invention is to provide a control method for automatically passing an off-road cross-axle condition, thereby enhancing the off-road escape performance of a vehicle and lowering the threshold for vehicle use by consumers.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A control method for automatically passing an off-road cross-axle condition comprises the following steps:

[0006] In response to a cross-axle mode activation request, determining whether a precondition for activation of the cross-axle mode is met; if the precondition for activation of the cross-axle mode is met, controlling the vehicle to enter a cross-axle operating state;

[0007] When the vehicle enters cross-axle mode:

[0008] The maximum torque of the wheel end can be called up while applying braking pressure to the wheel end;

[0009] Lock the gear in low gear;

[0010] Raise the vehicle's suspension height to the highest level;

[0011] Automatic locking rear axle differential lock;

[0012] The camera collects images around the vehicle body and displays them to the user;

[0013] And by judging whether the front or rear wheels of the vehicle are in a slipping or idling state, the torque of the front and rear axles is distributed, and the braking speed and braking pressure of the slipping or idling wheels are increased.

[0014] Preferably, in combination with the above solution, the activation preconditions include:

[0015] Determine whether the main driving door is closed;

[0016] Determine whether the driver's seat belt is fastened;

[0017] Determine whether the vehicle speed is zero;

[0018] Determine whether the brake pedal is depressed;

[0019] Determine whether the EPB is in a released state;

[0020] Determine whether the current gear is D gear;

[0021] Determine whether the steep slope descent function is turned off;

[0022] When all the judgment results are yes, the precondition for starting the cross-axis mode is met; if any judgment result is no, it is determined that the precondition for starting the cross-axis mode is not met.

[0023] Preferably, in combination with the above solution, when the vehicle is in the cross-axle mode, the vehicle speed is limited to 1-2 KPH.

[0024] Preferably, in combination with the above solution, when the vehicle is in the cross-axle mode, the cross-axle mode is automatically exited when the driver steps on the accelerator pedal and the vehicle speed exceeds a specified speed value and continues for a specified time.

[0025] Preferably, in combination with the above solution, after the vehicle exits the cross-axle mode, the vehicle automatically switches to the last driving mode.

[0026] Preferably, in combination with the above solution, when the vehicle is in the cross-axle mode, the driver steps on the accelerator pedal or the brake pedal, and the vehicle performs corresponding acceleration or braking control.

[0027] Preferably, in combination with the above solution, when the vehicle is in the cross-axle mode, the user can manually select whether to lock the front axle differential lock.

[0028] Preferably, in combination with the above solution, when the vehicle is in the cross-axle mode, the creep and coasting energy recovery functions are automatically turned off.

[0029] Preferably, in combination with the above solution, when the vehicle is in the cross-axle mode, the car's large screen displays the AVM interface to show the surrounding environment of the vehicle body.

[0030] Preferably, in combination with the above solution, when the vehicle is in the cross-axle mode, vehicle function fault reminders are displayed through the vehicle instrument and large screen, as well as prompts on how to operate in the cross-axle mode.

[0031] Preferably, in combination with the above scheme, when the vehicle is in cross-axle mode, when it is determined that the front wheels are in a slipping or idling state, the front axle reduces the torque and the rear axle increases the torque; when it is determined that the rear wheels are in a slipping or idling state, the front axle increases the torque and the rear axle reduces the torque.

[0032] Beneficial effects of the present invention: the present invention automatically passes the control method of the off-road cross-axle condition. When facing the cross-axle condition in the off-road scenario, the driver only needs to click the cross-axle mode option on the large screen to easily experience the cross-axle or steep slope condition only by controlling the steering wheel. There is no need for the driver to control the vehicle speed through the accelerator or brake pedal. The system will automatically complete the extremely low vehicle speed stable control of the cross-axle and other conditions. The driver can focus entirely on the road condition ahead, which greatly improves the off-road experience and sense of security. For some users with less off-road experience, this function can help users experience some cross-axle or steep slope conditions more safely and smoothly.

[0033] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A strategy diagram of a control method for automatically passing an off-road cross-axle condition according to the present invention.

[0035] Figure 2 A system structure diagram for implementing the control method of the present invention. DETAILED DESCRIPTION

[0036] like Figure 1 A control method for automatically passing an off-road cross-axle condition is shown, comprising the following steps:

[0037] In response to a cross-axle mode activation request, determine whether the activation preconditions of the cross-axle mode are met; if the activation preconditions of the cross-axle mode are met, control the vehicle to enter the cross-axle operating state; when the vehicle enters the cross-axle mode:

[0038] Applying brake pressure to the wheel end while the maximum torque at the wheel end can be called upon;

[0039] Lock the gear in a low gear (for example, in the first gear or L gear). In a low gear, the torque is very large, and ESC is responsible for the target vehicle speed stability control after the cross-axle is opened; use an extremely low speed to slowly pass the cross-axle road condition, ensuring sufficient power while making the vehicle body posture more stable, reducing the driver's panic during the dynamic process;

[0040] Raising the vehicle suspension height to the highest level can effectively improve the vehicle's passability;

[0041] Automatically lock the rear axle differential to prevent loss of power transmission in cross-axle conditions;

[0042] The camera collects images around the vehicle and displays them to the user on a large screen, so that the user can make appropriate maneuvers in time to avoid obstacles while the vehicle is driving;

[0043] And by judging whether the front or rear wheels of the vehicle are in a slipping or idling state, the torque of the front and rear axles is distributed, and the braking speed and braking pressure of the slipping or idling wheels are increased.

[0044] In order to ensure the normal operation of the cross-axis mode, the preconditions for starting include:

[0045] Determine whether the main driver's door is closed and whether the main driver's seat belt is fastened. When the main driver's door is closed and the main driver's seat belt is fastened, the driver's personal safety can be guaranteed when off-roading.

[0046] Determine whether the vehicle speed is zero and whether the brake pedal is pressed; when the brake pedal is pressed, the vehicle is stationary, so that the driver can prepare off-road driving equipment and ensure driving safety.

[0047] Determine whether the EPB electronic parking brake is in the released state. Only when the EPB electronic parking brake is in the released state can the vehicle be unlocked and move forward;

[0048] Determine whether the current gear is D gear. When the vehicle is in D gear, the vehicle will move forward normally;

[0049] Determine whether the hill descent control function is turned off; the hill descent control function allows the driver to smoothly pass through a steep downhill slope with full control without stepping on the brake pedal. This function will conflict with the cross-axle mode, so it needs to be turned off.

[0050] As the upper arbitration controller, the HCU controller is responsible for the arbitration of the conditions for opening, interrupting, and exiting the cross-axis mode. After the HCU arbitrates whether the above conditions are met, it will give text reminders through the ICM instrument. When all the above judgment results are yes, the preconditions for opening the cross-axis mode are met; if any judgment result is no, it is determined that the preconditions for opening the cross-axis mode are not met.

[0051] When the vehicle is in cross-axle mode, the speed is limited to a low speed of 1-2KPH, which can provide stronger power output while ensuring driving safety.

[0052] When the vehicle is in the cross-axle mode, the driver steps on the accelerator pedal and the vehicle speed exceeds the specified speed value and continues for a specified time, then the cross-axle mode will be automatically exited. When the vehicle speed exceeds the specified speed (e.g. 40KPH) and continues for a specified time (e.g. 10 seconds), it means that the vehicle has escaped or left the cross-axle condition, and the vehicle will automatically exit the cross-axle mode.

[0053] After the vehicle exits the cross-axle mode, it automatically switches to the last driving mode. For example, if the driver is in the snow mode before entering the cross-axle mode, the vehicle will return to the snow mode after the cross-axle mode is exited. This method increases the vehicle's control portability and intelligence.

[0054] When the vehicle is in the cross-axle mode, the driver presses the accelerator pedal or brake pedal, and the vehicle performs corresponding acceleration or braking control. In the case of automatic control in the cross-axle mode, the driver can actively control the acceleration and deceleration of the vehicle. If it is detected that the driver has no subjective request input (no accelerator pedal or brake pedal), the torque request is sent to the HCU according to the target gear speed to increase and maintain the vehicle driving force. At the same time, the ESC actively boosts and brakes to stabilize the speed; if it is detected that the driver has a subjective request input (pressing the accelerator pedal or brake pedal), the HCU responds to the driver's subjective request to control the vehicle speed.

[0055] When the vehicle is in cross-axle mode, the user can manually choose whether to lock the front axle differential lock. When the cross-axle mode is turned on, the rear axle differential lock is automatically locked to ensure the vehicle's passability, and the locking option of the front axle differential lock can be displayed on the large screen, and the driver can choose whether to manually lock the front axle differential lock to ensure steering stability and increase the vehicle's passability.

[0056] When the vehicle is in cross-axle mode, the creep and coasting energy recovery functions are automatically turned off. When the creep function is turned on, the torque interface of the cross-axle mode will conflict with the creep torque interface, affecting the torque of the vehicle's final response. And if coasting energy recovery is not turned off, when the driver steps on the accelerator to increase the vehicle speed and then releases the accelerator, the coasting energy recovery condition will be triggered, the vehicle speed control will be affected, and the functional performance of the cross-axle mode will be affected.

[0057] When the vehicle is in cross-axle mode, the AVM interface is displayed on the large screen to show the vehicle's surroundings. The driver can view the vehicle's surroundings through the 360-degree panoramic image on the large screen, so that he can make appropriate maneuvers in time to avoid obstacles, reduce vehicle scratches, and reduce off-road difficulty during driving.

[0058] In order to provide the driver with more intuitive information, when the vehicle is in cross-axle mode, the vehicle function fault reminder is displayed through the car instrument and large screen, as well as prompts on how to operate in cross-axle mode, such as asking the driver to choose whether to lock the front axle differential lock, and which conditions for turning on the cross-axle mode are not met. The function switch of the cross-axle mode is set on the large screen. When the user clicks the large screen to turn on the cross-axle mode switch, the ESC responds to turn on the cross-axle function; the HCU, as the upper arbitration controller, is responsible for the arbitration of the conditions for turning on, interrupting, and exiting the cross-axle function. After the HCU arbitrates whether the following conditions are met, it will give text reminders through the ICM instrument. The corresponding voice prompt information can also be given through the IHU infotainment audio host.

[0059] In order to avoid the waste of power output and improve the vehicle's ability to get out of trouble, when the vehicle is in the cross-axle mode, it is first determined whether the wheels are in a slipping or idling state (for example, in the prior art, it is determined by whether the speed difference between the front and rear axles exceeds a certain threshold, and whether the speed difference between the left and right wheels exceeds a certain threshold). The ESC electronic stability control system makes a torque request to the HCU through a specific torque interface; when it is determined that the front wheels are in a slipping or idling state, the front axle drive motor reduces the torque and the rear axle motor increases the drive torque to suppress the front wheels from slipping or idling; when it is determined that the rear wheels are in a slipping or idling state, the front axle drive motor increases the torque and the rear axle motor reduces the drive torque to suppress the rear wheels from slipping. The torque can be distributed proportionally. For example, in the standard mode, the torque distribution ratio of the front and rear axles is 5:5. When the rear wheels slip, the torque distribution ratio limit value of the front and rear axles can be set to 9:1; when the front wheels slip, the torque distribution ratio limit value of the front and rear axles can be set to 1:9.

[0060] In the standard mode of this embodiment, in order to protect the vehicle hardware and ensure driving safety, the maximum torque limit of the wheel end is 5600Nm, while in the cross-axle mode of this embodiment, the maximum torque of the entire wheel end is increased to 7300Nm, which almost does not limit the power output of the entire vehicle, and the braking control will be more active, quickly and actively intervene in the slipping wheels, and the braking pressure speed is faster than the standard mode, and the braking pressure is stronger. In the standard mode, the braking pressure applied to the slipping wheel within 0.3s is only 5MPa; while in the cross-axle mode, the braking pressure of 10MPa-16MPa can be applied to the slipping wheel within 0.3s to prevent the wheel from spinning, which can make the wheel power at the ground stronger and increase the ability to get out of trouble.

[0061] like Figure 2As shown, the vehicle in the embodiment of the present invention is provided with a CGW central gateway controller, a wheel speed sensor, an ESC electronic stability control system controller, an HCU hybrid vehicle controller, a brake pedal switch, an accelerator pedal position sensor, a FLZCU left domain controller, a prompt unit (including an ICM instrument cluster, an IHU infotainment audio host), an ADAS driving assistance system controller (the camera is a component in ADAS), etc.

[0062] The CGW central gateway controller is connected to the prompt unit for communication; the wheel speed sensor is used to detect the vehicle speed and send it to the CGW central gateway controller through the ESC electronic stability control system controller; the HCU hybrid vehicle controller sends the output torque to the CGW central gateway controller and each module controller on the same CAN line, and the controllers that are not on the same CAN line are forwarded to the corresponding CAN line through the CGW central gateway controller; the brake pedal switch is used to detect whether the brake pedal is pressed; the accelerator pedal position sensor is used to detect the throttle opening of the accelerator pedal; the FLZCU left domain controller sends the main driver's seat belt and main driver's door signals for the cross-axle mode working logic judgment; the prompt unit sends a cross-axle mode human-computer interaction text prompt; the ADAS driving assistance system controller is used to cooperate with the AVM to display the surrounding environment of the vehicle body, etc.

[0063] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or they are directly applied to other occasions without improvement, they all fall within the protection scope of the present invention.

Claims

1. A control method for automatically passing an off-road cross-axle condition, characterized in that: The following steps are involved: In response to a cross-axle mode activation request, determining whether a precondition for activation of the cross-axle mode is met; if the precondition for activation of the cross-axle mode is met, controlling the vehicle to enter a cross-axle operating state; When the vehicle enters cross-axle mode: The maximum torque of the wheel end can be called up while applying braking pressure to the wheel end; Lock the gear in low gear; Raise the vehicle's suspension height to the highest level; Automatic locking rear axle differential lock; The camera collects images around the vehicle body and displays them to the user; And by judging whether the front or rear wheels of the vehicle are in a slipping or idling state, the torque of the front and rear axles is distributed, and the braking speed and braking pressure of the slipping or idling wheels are increased.

2. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: The startup preconditions include: Determine whether the main driving door is closed; Determine whether the driver's seat belt is fastened; Determine whether the vehicle speed is zero; Determine whether the brake pedal is depressed; Determine whether the EPB is in a released state; Determine whether the current gear is D gear; Determine whether the steep slope descent function is turned off; When all the judgment results are yes, the precondition for starting the cross-axis mode is met; if any judgment result is no, it is determined that the precondition for starting the cross-axis mode is not met.

3. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: When the vehicle is in cross-axle mode, the speed is limited to 1-2KPH.

4. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: When the vehicle is in the cross-axle mode, the cross-axle mode will be automatically exited when the driver steps on the accelerator pedal and the vehicle speed exceeds the specified speed value and continues for a specified time.

5. The control method for automatically passing an off-road cross-axle condition according to claim 4 is characterized in that: After the vehicle exits the cross-axle mode, the vehicle automatically switches to the last driving mode.

6. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: When the vehicle is in cross-axle mode, the driver presses the accelerator pedal or brake pedal, and the vehicle performs corresponding acceleration or braking control.

7. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: When the vehicle is in cross-axle mode, the user can manually choose whether to lock the front axle differential lock.

8. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: When the vehicle is in cross-axle mode, the creep and coasting energy recovery functions are automatically turned off.

9. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: When the vehicle is in cross-axle mode, the car's large screen displays the AVM interface to show the surrounding environment of the vehicle.

10. The control method for automatically passing an off-road cross-axle condition according to claim 1, characterized in that: When the vehicle is in cross-axle mode, vehicle function malfunction reminders are displayed through the vehicle instrument panel and large screen, as well as instructions on how to operate in cross-axle mode.

11. The control method for automatically passing an off-road cross-axle condition according to claim 1 is characterized in that: When the vehicle is in cross-axle mode, when the front wheels are judged to be in a slipping or idling state, the front axle reduces the torque and the rear axle increases the torque; when the rear wheels are judged to be in a slipping or idling state, the front axle increases the torque and the rear axle reduces the torque.

Images