Methods, systems, and media for ramp creep control

Abstract

The present application relates to the field of vehicle control, and more particularly, to methods, systems, and computer storage media for ramp creep control. The invention provides a method for ramp crawling control, which is characterized by comprising the following steps of: detecting the running state of a vehicle to determine whether a ramp crawling closed-loop control condition is met or not; in response to determining that the ramp creep closed-loop control condition is satisfied, estimating a gradient of a ramp based on sensor data, and calculating a ramp torque required to compensate for the ramp; and on the basis of the acceleration of the vehicle, closed-loop control is conducted on the torque of the vehicle in a proportional-integral control mode.

Description

Technical Field

[0001] The present application relates to the field of vehicle control, and more particularly, to methods, systems, and computer storage media for hill creep control. Background Art

[0002] Creeping refers to the vehicle's steady forward or reverse motion at a low speed without pressing the accelerator pedal. This low-speed driving mode reduces frequent stops and starts on congested roads, improving driving comfort. Furthermore, the creeping function provides a stable low-speed driving state when parking or passing through toll booths, reducing the driver's operational burden. Controlling creeping becomes more complex when creeping on a slope (e.g., going uphill).

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0004] In order to solve or at least alleviate one or more of the above problems, the following technical solutions are provided: The embodiments of the present application provide a method for hill creep control, which can improve the problem of a vehicle easily slipping and sliding when creeping on a slope, and can improve the driving experience in the hill creep state.

[0005] According to a first aspect of the present application, a method for hill creep control is provided, the method comprising: detecting a driving state of a vehicle to determine whether a hill creep closed-loop control condition is satisfied; in response to determining that the hill creep closed-loop control condition is satisfied, estimating the slope of the slope based on sensor data, and calculating the ramp torque required to compensate for the slope; and performing closed-loop control of the vehicle's torque by proportional-integral control based on the vehicle's acceleration.

[0006] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, the driving state of the vehicle includes: accelerator pedal depth, vehicle speed, vehicle gear position, vehicle fault condition and slope condition.

[0007] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, the sensor data includes: acceleration data, wheel angular deceleration data, and pitch angle data.

[0008] As an alternative or supplement to the above scheme, in a method according to an embodiment of the present application, closed-loop control of the vehicle's torque includes: determining a target acceleration on the slope based on the estimated slope and vehicle speed; determining the vehicle's current actual acceleration; determining a required acceleration corresponding to the vehicle's torque, the required acceleration including the slope road resistance acceleration, the target acceleration, and a proportional-integral acceleration, wherein the slope road resistance acceleration is based on the slope torque, and the proportional-integral acceleration is based on the difference between the target acceleration and the vehicle's current actual acceleration; and controlling the vehicle's torque based on the required acceleration.

[0009] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, in torque closed-loop control, the torque of the front and rear axles of the vehicle is distributed based on the load of the vehicle.

[0010] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, the method further includes: in response to detecting an accelerator pedal command, transitioning from the closed-loop control to an accelerator pedal open-loop control.

[0011] As an alternative or supplement to the above scheme, in a method according to an embodiment of the present application, the transition from the closed-loop control to the accelerator pedal open-loop control includes: determining the difference between the torque indicated by the accelerator pedal command and the ramp torque; when the difference is negative, controlling the vehicle's torque according to the sum of the torque indicated by the accelerator pedal command and the ramp torque; when the difference is positive, controlling the vehicle's torque according to the sum of the torque indicated by the accelerator pedal command and the ramp torque, and gradually reducing the vehicle's torque until the vehicle's torque is equal to the torque indicated by the accelerator pedal command.

[0012] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, the method further includes: in response to detecting a brake pedal command, transitioning from the closed-loop control to a brake pedal open-loop control.

[0013] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, in the open-loop control of the brake pedal, when the vehicle recognizes a scenario associated with the risk of rolling down the slope and the vehicle is about to stop, hydraulic parking is activated to avoid rolling down the slope.

[0014] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, the scenarios associated with the risk of rolling down a slope include: activation of a traction control system due to low road adhesion; limited output torque due to a drive system failure; and excessive slope of a slope.

[0015] As an alternative or supplement to the above solution, in a method according to an embodiment of the present application, in response to determining that the hill creep closed-loop control condition is no longer satisfied, a braking instruction is issued and the closed-loop control is exited.

[0016] According to a second aspect of the present application, a system for hill creep control is provided, the system comprising a processor; a memory; and a computer program, the computer program being stored on the memory and executable on the processor, the execution of the computer program enabling any one of the methods described in the first aspect of the present application to be executed.

[0017] According to a third aspect of the present application, a computer storage medium is provided, wherein the computer storage medium comprises instructions, and the instructions, when executed, execute any one of the methods described in the first aspect of the present application.

[0018] The hill creep control method according to one or more embodiments of the present application can reduce the risk of slipping and skidding when a vehicle is creeping on a slope, providing a better driving and riding experience, making the vehicle feel as if it is driving on flat ground. Furthermore, the method can naturally transition from automatic closed-loop creep control to open-loop control using the accelerator and brake pedals, reducing the sense of fluctuation during the transition. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or other aspects and advantages of the present application will become clearer and easier to understand through the following description of various aspects in conjunction with the accompanying drawings, in which the same or similar elements are represented by the same reference numerals. In the drawings:

[0020] Figure 1 is a flowchart of a method 100 for hill creep control according to an embodiment of the present application;

[0021] Figure 2 is a flow chart of a method 200 for closed-loop controlling a vehicle's torque based on the vehicle's acceleration according to an embodiment of the present application;

[0022] Figure 3 is a flowchart 300 of exit ramp creep torque closed-loop control according to one embodiment of the present application; and

[0023] Figure 4 is a block diagram of a system 40 for hill creep control according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] The description of the following specific embodiments is merely exemplary in nature and is not intended to limit the disclosed technology or the application and use of the disclosed technology. In addition, there is no intention to be bound by any express or implied theory presented in the foregoing technical field, background technology or the following specific embodiments.

[0025] In the following detailed description of the embodiments, numerous specific details are set forth to provide a more thorough understanding of the disclosed technology. However, it will be apparent to one of ordinary skill in the art that the disclosed technology can be practiced without these specific details. In other instances, well-known features are not described in detail to avoid unnecessarily complicating the description.

[0026] Terms such as "having" and "including" indicate that in addition to the units (modules) and steps that are directly and clearly stated in the specification and claims, the technical solution of this application does not exclude the situation where it has other units (modules) and steps that are not directly or clearly stated. Terms such as "first" and "second" do not indicate the order of units in terms of time, space, size, etc., but are only used to distinguish between the units. Moreover, the steps in this article are not limited to being implemented in the order written, but the steps written later can also be implemented at the same time as the steps written earlier, or before the steps written earlier.

[0027] Generally, on a slope, it is necessary to provide sufficient driving torque according to the slope / vehicle speed to meet the requirement of being able to climb a slope of less than 20 degrees at a speed of 3kph to 7kph. The target speed is set according to the size of the slope. The larger the slope, the lower the target speed. This can not only enhance the user's sense of security when crawling on a large slope, but also make full use of the change in target speed to overcome the torque impact caused by entering and exiting the slope. However, when the vehicle slowly climbs up the slope in a creeping state, in order to limit the vehicle's speed and acceleration, the torque output by the vehicle is usually lower. Due to the slope of the slope, there may be a greater risk of slipping and skidding than when crawling on flat ground, which in turn endangers driving safety and personal safety.

[0028] One or more embodiments of the present application will be described below with reference to the accompanying drawings.

[0029] refer to Figure 1 , Figure 1 1 is a flow chart of a method 100 for hill creep control according to one embodiment of the present application. In step 102, the vehicle's driving state is detected. In one embodiment, the vehicle's driving state includes: accelerator pedal depth, vehicle speed, vehicle gear position, vehicle fault conditions, hill conditions, and other safety function adjustments.

[0030] Then, in step 104, it is determined whether the vehicle's driving state meets the hill creep closed-loop control conditions. Specifically, the hill creep closed-loop control conditions are met when the accelerator pedal depth is zero (i.e., the accelerator pedal is not depressed), the vehicle speed is low, the vehicle gear is in a lower gear of the forward gear (D gear), the vehicle is currently traveling uphill, and there are no other vehicle fault alarms.

[0031] Next, in step 106, the slope of the ramp is estimated based on the sensor data, and the ramp torque required to compensate for the ramp is calculated. The sensor data includes acceleration data, wheel angular deceleration data, and pitch angle data. Based on this sensor data, an intelligent algorithm can be used to estimate the current slope (e.g., 15 degrees). Based on this slope, the ramp torque required to compensate for the ramp is further calculated. This ramp torque can offset the downward component of the gravity force exerted on the vehicle on the ramp.

[0032] In step 108, closed-loop control of the vehicle's torque is performed using proportional-integral control (PI) based on the vehicle's acceleration. PI (Proportional-Integral Control) is a common closed-loop control algorithm that adjusts the output based on the deviation between the target and actual values, allowing the system's actual output to gradually approach and stabilize at the target value.

[0033] Depending on the size of the slope, the target speed of the vehicle creeping on the slope is also different. For example, when the vehicle is creeping on flat ground (i.e., the slope is zero), the target creep speed may be 7 km / h. When the vehicle is creeping on a 15-degree slope, the target creep speed may be 4 km / h. During the creep control process, the acceleration of the vehicle can be changed by adjusting the torque output of the vehicle, and thus the speed of the vehicle can be changed. For example, in order to keep the vehicle creeping at a speed of 4 km / h, when the speed is higher than 4 km / h, the target acceleration of the vehicle is negative (i.e., it is desired that the vehicle reduce its speed), when the speed is lower than 4 km / h, the target acceleration of the vehicle is positive (i.e., it is desired that the vehicle increase its speed), and when the speed is at 4 km / h, the target acceleration of the vehicle is zero (i.e., it is desired that the vehicle maintain its current speed).

[0034] In one embodiment, at a certain moment, the vehicle is creeping at a target speed of 4 km / h, and the acceleration of the vehicle at that moment may be 1 m / s 2At this point, although the vehicle is still traveling at the target speed, it will soon exceed it (due to the deviation between the actual acceleration and the target acceleration), so torque adjustment is required. By comparing the target acceleration at the target speed with the actual acceleration, the controller controlling the vehicle's creep can determine that it should immediately reduce the vehicle's torque to prevent the vehicle from exceeding the target speed.

[0035] As another example, at a certain moment, the vehicle is crawling at a speed of 5 km / h, and the acceleration of the vehicle at that moment may be -1 m / s 2 Although the vehicle speed is not equal to the target speed (for example, 4 km / h) at this time, the vehicle speed is about to drop to the target speed according to the acceleration change trend at this time (because the actual acceleration is close to the target acceleration), so there is no need to intervene temporarily.

[0036] By adjusting the vehicle torque at a certain speed using the difference between the target acceleration corresponding to the speed and the actual acceleration, the vehicle speed can be adjusted to the desired speed more quickly, thereby promoting smooth creeping of the vehicle.

[0037] Next reference Figure 2 To describe the detailed process of closed-loop control of vehicle torque based on vehicle acceleration. Figure 2 FIG. 2 is a flow chart of a method 200 for closed-loop control of vehicle torque based on vehicle acceleration according to an embodiment of the present application. Figure 2 As shown in FIG, in step 202, the target acceleration on the slope is determined based on the estimated slope and vehicle speed. For example, when the slope is estimated to be 15 degrees and the current vehicle speed is 4 km / h in step 106, the target acceleration on the slope can be determined to be 0 m / s. 2 In another example, when the slope is 15 degrees and the current vehicle speed is 6 km / h, the target acceleration on the slope is -1 m / s 2 In a low speed range (e.g., 0-10 km / h), the target acceleration may decrease as the vehicle speed increases. In a higher speed range (e.g., above 10 km / h), the target acceleration may be a constant value (i.e., negative acceleration in the vehicle's power recovery mode when the accelerator is not depressed).

[0038] Then, in step 204, the current actual acceleration of the vehicle is determined. The current actual acceleration can be obtained from an acceleration sensor of the vehicle, or by calculating the change in vehicle speed.

[0039] Next, in step 206, the required acceleration corresponding to the vehicle torque is determined. n Represents the torque T output by the vehicled The acceleration that can be provided on flat ground. When the vehicle is crawling on the slope, the actual acceleration of the vehicle is a r The vehicle output torque T d The relationship can be expressed as:

[0040]

[0041] Among them, T s is the ramp torque required to compensate for the ramp. Accordingly, formula (1) can be rewritten as:

[0042]

[0043] Among them, a s is the torque corresponding to the ramp, T s Furthermore, the relationship between the actual acceleration of the vehicle and the target acceleration of the vehicle can be expressed as:

[0044] a r =a t +a Δ (3)

[0045] Among them, a t is the target acceleration of the vehicle, a Δ Indicates the difference between the actual acceleration of the vehicle and the target acceleration. In theory, when the vehicle outputs torque T d Just enough to provide the slope resistance torque T s and the target acceleration a t When the corresponding torque is equal to the target acceleration, the actual acceleration of the vehicle should be equal to the target acceleration of the vehicle. However, in reality, the slope of the slope may not be constant, the state of the vehicle (for example, total weight, tire friction, etc.) may also change, or the road resistance may vary due to different road materials. Therefore, the actual acceleration often deviates from the target acceleration. Δ Input to the proportional-integral controller to obtain the adjustment value of the torque command that needs to be adjusted.

[0046] According to the above formulas (2) and (3), the required acceleration a n It can be expressed as:

[0047] a n =a s +a t +a Δ (4)

[0048] As shown in formula (4), the required acceleration a n Including slope road resistance acceleration a s Target acceleration at and the proportional integral acceleration a Δ , where slope road resistance acceleration a s With the target acceleration a t is the base value, proportional integral acceleration a Δ is the adjustment value, slope road resistance acceleration a s Based on the ramp torque T s , proportional integral acceleration a Δ Based on the vehicle's current actual acceleration a r With the target acceleration a t The difference between.

[0049] Next, at step 208, the torque of the vehicle is controlled based on the required acceleration. n , the torque T required for the vehicle to output can be determined d , then, based on a Δ Closed-loop control of torque can make the vehicle's actual acceleration on the slope close to the target acceleration, thereby obtaining an excellent driving and riding experience.

[0050] In some embodiments, torque closed-loop control can also distribute the torque between the front and rear axles based on the vehicle's load. For example, the torque between the front and rear axles can be adjusted based on the front and rear load distribution to fully utilize ground adhesion and prevent slippage.

[0051] After the vehicle enters hill creep torque control, it can creep steadily up the slope at the target speed without human intervention until it exits hill creep torque closed-loop control.

[0052] Next reference Figure 3 , Figure 3 FIG3 is a flowchart 300 of the closed-loop control of creep torque for exiting a ramp according to an embodiment of the present application. Figure 3As shown in FIG, in step 302, the vehicle is in a hill creep torque closed-loop control state, creeping at a target speed while maintaining actual acceleration at the target acceleration through proportional-integral control. Then, in step 3041, in response to detecting an accelerator pedal command, the hill creep torque closed-loop control is exited, and a gradual transition to accelerator pedal open-loop control 3081 is made via step 3061. In step 3061, to provide a smooth transition, the difference between the torque indicated by the accelerator pedal command and the hill torque is first determined. If the difference is negative (i.e., the torque indicated by the accelerator pedal command is insufficient to overcome the hill torque), directly outputting the corresponding torque according to the accelerator pedal command will not only fail to accelerate the vehicle, but may also cause the vehicle to run off the hill, which may not be in line with the driver's driving intention. Therefore, when the difference is negative, the vehicle torque is controlled according to the sum of the torque indicated by the accelerator pedal command and the hill torque, with the hill torque responsible for overcoming the effects of the hill, and the torque indicated by the accelerator pedal command responsible for accelerating the vehicle. In this way, when the driver depresses the accelerator during hill creep closed-loop torque control to accelerate, the vehicle can accelerate even with a slight depressing of the accelerator pedal. Similarly, when the difference is positive (i.e., the torque indicated by the accelerator pedal command is sufficient to overcome the hill torque), the vehicle's torque is controlled based on the sum of the torque indicated by the accelerator pedal command and the hill torque. However, to prevent excessive acceleration on a hill, the vehicle's torque is gradually reduced until the vehicle's torque equals the torque indicated by the accelerator pedal command. This balances driving experience and safety.

[0053] In another case, in step 302, the vehicle is in a hill creep torque closed-loop control state, the vehicle creeps at a target speed, and the actual acceleration is maintained at the target acceleration through proportional-integral control. Then, in step 3043, in response to detecting a brake pedal command, the hill creep torque closed-loop control is exited, and a gradual transition to brake pedal open-loop control 3082 is made via step 3063. In order to prevent the vehicle from rolling down a slope due to excessive braking on a slope, after exiting the hill creep torque closed-loop control, when the vehicle identifies a scenario associated with a risk of rolling down a slope and the vehicle is about to stop, hydraulic parking is activated to avoid rolling down the slope. In some embodiments, the scenarios associated with the risk of rolling down a slope include: activation of the traction control system due to low road adhesion; limited output torque due to a drive system failure; and excessive slope of the slope. In addition, when the vehicle speed is too low (e.g., below -0.1 km / h), the parking function is actively requested to intervene.

[0054] In addition to the situations of 3041 and 3043 triggered by external command intervention, in step 3042, when any of the hill creep closed-loop control conditions is no longer met, the hill creep torque closed-loop control is actively exited. For example, if the vehicle's drive system fails during the hill creep closed-loop torque control process and may affect the vehicle's torque output, in step 3062, a braking instruction is issued to remind the driver to take over and exit the hill creep closed-loop torque control. In another embodiment, when the slope has ended, step 3062 is also entered to exit the hill creep closed-loop torque control. The driver then needs to control the vehicle through conventional accelerator pedal open-loop control 3081 and brake pedal open-loop control 3082.

[0055] Figure 4 4 is a block diagram of a system 40 for hill creep control according to an embodiment of the present application. The system 40 includes a memory 410, a processor 420, and a computer program 430 stored in the memory 410 and executable on the processor 420. The execution of the computer program 430 enables the following Figure 1 The illustrated method 100 is executed.

[0056] In addition, as described above, the present application can also be implemented as a computer storage medium, in which a program for causing a computer to execute the method described in any of the above embodiments is stored. Here, as a computer storage medium, various computer storage media can be used, such as disks (e.g., magnetic disks, optical disks, etc.), cards (e.g., memory cards, optical cards, etc.), semiconductor memories (e.g., ROMs, non-volatile memories, etc.), and tapes (e.g., magnetic tapes, cassettes, etc.).

[0057] In the applicable situation, the combination of hardware, software or hardware and software can be used to realize the various embodiments provided by the application. Moreover, in the applicable situation, without departing from the scope of the application, the various hardware components and / or software components set forth herein can be combined into a composite component comprising software, hardware and / or both. In the applicable situation, without departing from the scope of the application, the various hardware components and / or software components set forth herein can be divided into a subcomponent comprising software, hardware or both. In addition, in the applicable situation, it is contemplated that the software component can be implemented as a hardware component, and vice versa.

[0058] Software according to the present application (such as program code and / or data) can be stored on one or more computer storage media. It is also contemplated that the software identified herein can be implemented using one or more general or special computers and / or computer systems, networked and / or otherwise. Where applicable, the order of the various steps described herein can be changed, combined into composite steps and / or divided into sub-steps to provide the features described herein.

[0059] The embodiments and examples set forth herein are provided to best illustrate embodiments according to the present application and its specific applications, and thereby enable those skilled in the art to make and use the present application. However, those skilled in the art will appreciate that the above description and examples are provided for ease of illustration and example only. The descriptions set forth are not intended to be exhaustive of all aspects of the present application or to limit the present application to the precise forms disclosed.

Claims

1. A method for hill creep control, characterized in that: The method comprises: Detect the vehicle's driving state to determine whether the slope creep closed-loop control conditions are met; In response to determining that the hill creep closed-loop control condition is satisfied, estimating the gradient of the hill based on sensor data and calculating a hill torque required to compensate for the hill; and Based on the vehicle's acceleration, the vehicle's torque is closed-loop controlled through proportional-integral control.

2. The method according to claim 1, wherein The driving state of the vehicle includes: accelerator pedal depth, vehicle speed, vehicle gear position, vehicle fault condition and slope condition.

3. The method according to claim 1, wherein The sensor data includes acceleration data, wheel angular deceleration data, and pitch angle data.

4. The method according to claim 1, wherein Closed-loop control of vehicle torque includes: determining a target acceleration on the slope based on the estimated slope and vehicle speed; Determine the current actual acceleration of the vehicle; determining a required acceleration corresponding to the torque of the vehicle, the required acceleration comprising a hill drag acceleration, the target acceleration, and a proportional-integral acceleration, wherein the hill drag acceleration is based on the hill torque, and the proportional-integral acceleration is based on a difference between the target acceleration and a current actual acceleration of the vehicle; The torque of the vehicle is controlled based on the requested acceleration.

5. The method according to claim 1, wherein In torque closed-loop control, torque is distributed between the front and rear axles of the vehicle based on the vehicle's load.

6. The method of claim 1, wherein: The method further includes transitioning from the closed-loop control to throttle pedal open-loop control in response to detecting an throttle pedal command.

7. The method according to claim 6, wherein: Transitioning from the closed-loop control to the accelerator pedal open-loop control includes: determining a difference between a torque indicated by the accelerator pedal command and the ramp torque; When the difference is negative, controlling the torque of the vehicle according to the sum of the torque indicated by the accelerator pedal command and the hill torque; When the difference is positive, the vehicle torque is controlled according to the sum of the torque indicated by the accelerator pedal command and the hill torque, and the vehicle torque is gradually reduced until the vehicle torque is equal to the torque indicated by the accelerator pedal command.

8. The method of claim 1, wherein: The method further includes transitioning from the closed-loop control to brake pedal open-loop control in response to detecting a brake pedal command.

9. The method of claim 8, wherein: In the brake pedal open-loop control, when the vehicle recognizes a scenario associated with a risk of rolling down a slope and the vehicle is about to stop, hydraulic parking is activated to avoid rolling down the slope.

10. The method of claim 9, wherein: The scenarios associated with the landslide risk include: Activation of the traction control system due to low road adhesion; Output torque limitation due to drive system failure; and The slope of the ramp is too steep.

11. The method of claim 1, wherein: In response to determining that the hill creep closed-loop control condition is no longer satisfied, a braking instruction is issued and the closed-loop control is exited.

12. A system for hill creep control, characterized in that: The system includes processor; Memory; as well as A computer program is stored on the memory and can be run on the processor, and the execution of the computer program causes the method according to any one of claims 1 to 11 to be performed.

13. A computer storage medium, characterized in that The computer storage medium includes instructions that, when executed, perform the method according to any one of claims 1-11.

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