Parking brake control method, control device, vehicle, and storage medium

Abstract

The application discloses a parking brake control method, a control device, a vehicle and a storage medium, and relates to the technical field of vehicles. The parking brake control method comprises the following steps: acquiring the slope of a slope where the vehicle is located and judging whether the slope meets a preset slope range; when the slope is in the preset slope range, judging the relationship between the driving direction of the vehicle and the slope; when the driving direction is uphill, acquiring the brake pressure of the vehicle and judging the size relationship between the brake pressure and a preset pressure; when the brake pressure is greater than or equal to the preset pressure, controlling the EPB to switch to a first working mode, and triggering the HHC of the vehicle. The parking brake control method judges the working modes of the EPB and the HHC through the information of the slope where the vehicle is located and the brake pressure of the vehicle, so that the two functions are matched with each other, the smoothness of the vehicle when starting on the slope can be ensured, and the problem of the whole vehicle sliding on the slope can be avoided.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a parking brake control method, control device, vehicle, and storage medium. Background Technology

[0002] The Electronic Park Brake (EPB), also known as the electronic handbrake, is a common feature in passenger cars. To increase user convenience, the EPB has developed a release function, which automatically releases the EPB when the vehicle is not rolling backwards, based on the driver's throttle opening and the actual driving torque of the vehicle. However, due to the limitations of the EPB's mechanical structure, the EPB release time is about 1 second. But the response time of the vehicle's (gasoline car) powertrain is less than 100ms (the response time of the electric vehicle's powertrain is even faster). Therefore, during the EPB release process, there is a process where the torque is close to the driving torque, resulting in an uneven start for the vehicle.

[0003] To improve the above situation, the relevant technology has developed a logic for EPB to release when shifting from P gear. That is, EPB starts to release when the brake pedal is pressed to shift gears, and when the driver moves his foot from the brake pedal to the accelerator pedal to start, EPB has been basically released, so that the start can be smooth.

[0004] The logic of EPB release when leaving Park applies to starting the car on a flat road, ensuring smoothness during starts. However, when the vehicle is on a slope, if the driver presses the brake pedal to shift gears, the vehicle has little or no driving force while the brake pedal is depressed. After releasing the brake pedal, there is a time gap before pressing the accelerator pedal. During this gap, because EPB has already been released after the brake pedal is released and the vehicle has no braking force, driving force has not been established, causing the vehicle to roll backward. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a parking brake control method that can ensure the smoothness of vehicle start-up on a slope and avoid the problem of the vehicle rolling backward.

[0006] The present invention also provides a control device, a vehicle, and a storage medium for performing the above-described parking brake control method.

[0007] According to a first aspect of the present invention, a parking brake control method is applied to a vehicle having an electronic parking brake system and a hill start assist system, comprising the following steps:

[0008] The slope of the ramp where the vehicle is located is obtained, and it is determined whether the slope is within a preset slope range. The preset slope range is the range within which the vehicle is at risk of rolling back and the ramp start assist system can stop the vehicle within the slope range.

[0009] When the slope is within the preset slope range, the relationship between the driving direction and the slope is determined based on the driving direction of the vehicle.

[0010] When the driving direction is uphill, the braking pressure of the vehicle is obtained, and the relationship between the braking pressure and the preset pressure is determined based on the braking pressure. The preset pressure is the braking force that stops the vehicle on the slope without the risk of rolling back.

[0011] When the braking pressure is greater than or equal to the preset pressure, the electronic parking brake system is controlled to switch to the first working mode, and the vehicle is controlled to trigger the hill start assist system according to the signal that the electronic parking brake system has completed the release. The first working mode is the working mode in which the electronic parking brake system releases according to the driver's action of pressing the brake pedal.

[0012] The parking brake control method according to embodiments of the present invention has at least the following beneficial effects: when the vehicle is parked on a slope, the electronic parking brake system is triggered and brakes the vehicle; when starting on a slope, the driver presses the brake pedal to shift gears, during which the slope of the slope where the vehicle is located is acquired, and it is determined whether the slope is within a preset slope range; when the slope is within the preset slope range, i.e., the slope is such that the vehicle is at risk of rolling back, and the hill start assist system is triggered to stop the vehicle within the slope range, the relationship between the driving direction and the slope is determined based on the vehicle's driving direction; when the driving direction is uphill, the braking pressure of the vehicle is acquired, and the relationship between the braking pressure and the preset pressure is determined based on the braking pressure. The preset braking pressure is the braking force that stops the vehicle on the slope without the risk of rolling back. When the braking pressure is greater than or equal to the preset pressure, the electronic parking brake system is switched to the first working mode, and the vehicle triggers the hill start assist system. The first working mode is the working mode in which the electronic parking brake system is released when the driver depresses the brake pedal to shift gears (that is, the electronic parking brake system begins to release during the driver's shifting and is fully released when the driver completes the shift and depresses the accelerator pedal). After the hill start assist system is triggered, the vehicle starts with the assistance of the hill start assist system. Through the above parking brake control method, the smoothness of the vehicle when starting on a slope can be guaranteed, and the problem of the whole vehicle rolling back on the slope can be avoided.

[0013] According to some embodiments of the present invention, the parking brake control method further includes the step of: when the driving direction is downhill, controlling the electronic parking brake system to switch to the first working mode.

[0014] According to some embodiments of the present invention, controlling the electronic parking brake system to switch to a first operating mode, and the vehicle triggering the hill start assist system based on the signal indicating that the electronic parking brake system has completed releasing, includes the following steps: acquiring a shifting action signal from the driver to the vehicle, and determining whether the shifting action is completed based on the shifting action signal; when the shifting action is completed, controlling the electronic parking brake system to release the braking output to the vehicle, activating the hill start assist system and controlling the vehicle to maintain braking output responsive to the brake pedal; acquiring a pressing action signal from the driver to the accelerator pedal, and determining whether the pressing action has started based on the pressing action signal; when the pressing action starts, and the driving force output by the vehicle in response to the accelerator pedal meets the hill start requirements, releasing the hill start assist system from controlling the vehicle, and releasing the vehicle's braking output in response to the brake pedal.

[0015] According to some embodiments of the present invention, activating the hill start assist system and controlling the vehicle to maintain braking output in response to the brake pedal further includes the steps of: controlling the vehicle to maintain braking output in response to the brake pedal for a preset time; when the preset time is exceeded or the driving force meets the hill start requirements, releasing the control of the hill start assist system on the vehicle and releasing the braking output of the vehicle in response to the brake pedal.

[0016] According to some embodiments of the present invention, the parking brake control method further includes the steps of: when the slope is less than the preset slope range, controlling the electronic parking brake system to switch to the first working mode; acquiring the driver's gear shifting action signal on the vehicle, and determining whether the gear shifting action is completed based on the gear shifting action signal; when the gear shifting action is completed, releasing the braking output of the electronic parking brake system on the vehicle.

[0017] According to some embodiments of the present invention, the parking brake control method further includes the steps of: when the slope is greater than the preset slope range, determining the relationship between the vehicle's driving direction and the slope; when the driving direction is uphill, controlling the electronic parking brake system to switch to a second working mode, wherein the second working mode is a working mode in which the electronic parking brake system releases the brake according to the driving force output by the vehicle in response to the accelerator pedal.

[0018] According to some embodiments of the present invention, controlling the electronic parking brake system to switch to a second operating mode includes the following steps: controlling the electronic parking brake system to maintain braking output to the vehicle; acquiring a driver's depressor action signal on the accelerator pedal, and determining the magnitude of the driving force output by the vehicle in response to the accelerator pedal based on the depressor action signal; when the driving force is greater than a preset driving force, releasing the braking output of the electronic parking brake system on the vehicle, wherein the preset driving force is the driving force required to enable the vehicle to meet the requirements for hill start.

[0019] According to a second aspect of the present invention, a parking brake control device is used to execute the parking brake control method of the first aspect of the present invention. The control device includes:

[0020] The acquisition module is configured to acquire the slope of the ramp where the vehicle is located, and to acquire the braking pressure of the vehicle.

[0021] The first determining module is configured to determine whether the slope is within a preset slope range based on the slope. When the slope is within the preset slope range, the module determines the relationship between the driving direction and the slope based on the driving direction of the vehicle. The preset slope range indicates that the vehicle is at risk of rolling back, and triggering the slope start assist system can stop the vehicle within the slope range of the slope.

[0022] The second determining module is configured to determine the relationship between the braking pressure and a preset pressure based on the braking pressure when the driving direction is uphill. The preset pressure is the braking force that stops the vehicle on the slope without the risk of rolling back.

[0023] The execution module is configured to control the electronic parking brake system to switch to a first working mode when the braking pressure is greater than or equal to the preset pressure, and to control the vehicle to trigger the hill start assist system according to the signal that the electronic parking brake system has completed release.

[0024] The parking brake control device according to an embodiment of the present invention has at least the following beneficial effects: When a vehicle needs to start on a slope, the driver presses the brake pedal to shift gears. During this process, the acquisition module acquires the slope of the slope where the vehicle is located, and the first determination module determines whether the slope meets the preset slope range. When the first determination module determines that the slope is within the preset slope range, the first determination module determines the relationship between the vehicle's driving direction and the slope. When the first determination module determines that the vehicle's driving direction is uphill, the acquisition module acquires the vehicle's braking pressure. The second determination module determines the relationship between the braking pressure and the preset pressure based on the braking pressure. When the second determination module determines that the braking pressure is greater than or equal to the preset pressure, the execution module controls the electronic parking brake system to switch to the first working mode and controls the vehicle to trigger the hill start assist system. The vehicle starts with the assistance of the hill start assist system. By executing the parking brake control method through the control device, the smoothness of the vehicle when starting on a slope can be guaranteed, and the problem of the vehicle rolling backwards on the slope can be avoided.

[0025] According to a third aspect of the present invention, a vehicle includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein when the program is executed by the processor, it implements the parking brake control method as described in the first aspect of the above embodiments.

[0026] According to a fourth aspect of the present invention, a computer-readable storage medium stores computer-executable instructions for causing a computer to perform the parking brake control method as described in the first aspect of the above embodiments.

[0027] Since both the vehicle and the computer-readable storage medium are used to perform the parking brake control method as described in the first aspect of the above embodiments, they have at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0028] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0029] Figure 1 This is a flowchart of a parking brake control method according to an embodiment of the present invention;

[0030] Figure 2 yes Figure 1 The flowchart showing the specific steps of the first case of step S200 is shown.

[0031] Figure 3 yes Figure 1 The flowchart showing the specific steps of step S400 is shown.

[0032] Figure 4yes Figure 3 The flowchart showing the specific steps of step S4002 is shown.

[0033] Figure 5 yes Figure 1 The flowchart showing the specific steps of the second case of step S200 is shown.

[0034] Figure 6 yes Figure 1 The flowchart showing the specific steps of the third case of step S200 is shown.

[0035] Figure 7 yes Figure 6 The flowchart showing the specific steps of step S250 is shown.

[0036] Figure 8 This is a block diagram of a parking brake control device according to an embodiment of the present invention;

[0037] Figure 9 This is a flowchart illustrating a specific example of a parking brake control method according to an embodiment of the present invention. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0039] In the description of this invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0040] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0041] In the description of this invention, it should be noted that terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0042] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0043] Electronic parking brake (EPB) systems are already a common feature in passenger cars. To increase user convenience, EPB has developed a release function, which automatically releases the EPB when the vehicle is not rolling backwards, based on the driver's throttle opening and the actual driving torque of the vehicle. However, due to the limitations of the EPB's mechanical structure, the EPB release time is about 1 second. But for gasoline vehicles, the response time of the entire powertrain is less than 100ms, and this response time is even smaller for electric vehicles. Therefore, there is a process during the EPB release that is close to the driving torque, resulting in an uneven start for the vehicle.

[0044] To improve the above situation, the relevant technology has developed a logic for EPB to release when shifting from P gear. That is, EPB starts to release when the brake pedal is pressed to shift gears, and when the driver moves his foot from the brake pedal to the accelerator pedal to start, EPB has been basically released, so that the start can be smooth.

[0045] The logic of EPB release when leaving Park applies to starting the car on a flat road, ensuring smoothness during starts. However, when the vehicle is on a slope, if the driver presses the brake pedal to shift gears, the vehicle has little or no driving force while the brake pedal is depressed. After releasing the brake pedal, there is a time gap before pressing the accelerator pedal. During this gap, because EPB has already been released after the brake pedal is released and the vehicle has no braking force, driving force has not been established, causing the vehicle to roll backward.

[0046] To address the aforementioned problems, this invention proposes a parking brake control method, control device, vehicle, and storage medium. The method determines whether the EPB (Electronic Parking Brake) should be released based on the conditions of the slope and the driver's braking pressure. In conjunction with a Hill Hold Control (HHC) system, the method enables the vehicle to start smoothly on a slope.

[0047] Reference Figures 1 to 9 The parking brake control method and control device according to embodiments of the present invention are shown below, and specific embodiments will be described in detail below.

[0048] Reference Figure 1 As shown, the parking brake control method of the first aspect of the present invention includes, but is not limited to, the following steps:

[0049] Step S100: Obtain the slope of the ramp where the vehicle is located, and determine whether the slope is within the preset slope range. The preset slope range is the range where the vehicle is at risk of rolling downhill and triggering HHC can stop the vehicle on the ramp.

[0050] Step S200: When the slope is within the preset slope range, determine the relationship between the driving direction and the slope based on the vehicle's driving direction;

[0051] Step S300: When the driving direction is uphill, obtain the vehicle's braking pressure, and determine the relationship between the braking pressure and the preset pressure based on the braking pressure. The preset pressure is the braking force that stops the vehicle on the slope without the risk of rolling back.

[0052] In step S400, when the braking pressure is greater than or equal to the preset pressure, the EPB is controlled to switch to the first working mode, and the vehicle is controlled to trigger HHC according to the signal that the EPB has completed the release. The first working mode is the working mode in which the EPB releases according to the driver's action of pressing the brake pedal.

[0053] Understandably, vehicles using the aforementioned control method need to be equipped with EPB and HHC. The release of EPB and the activation of HHC are determined by the gradient and vehicle braking pressure. The control method coordinates EPB and HHC to ensure a smoother start on an incline without slipping. After shifting gears, when the driver presses the accelerator, there is no struggle between the vehicle's driving force and the braking output of EPB, thus avoiding vibrations during start-up and resulting in excellent start-up smoothness.

[0054] It should be noted that the EPB has two operating modes: the first operating mode and the second operating mode. The first operating mode is the EPB's release mode when leaving Park, and the second operating mode is the EPB's automatic release mode (also known as the drive-out release mode).

[0055] Understandably, the workflow for the first operating mode of the EPB is as follows: During the driver's shifting process (from park to drive or reverse), the EPB begins to release, gradually disengaging the braking output to the vehicle; once the driver completes the shift, the EPB is fully released, releasing the braking output. For the second operating mode of the EPB, the workflow is as follows: During the driver's shifting process, the EPB remains engaged, maintaining braking output; after the driver completes the shift, the EPB continues to maintain braking output; when the driver depresses the accelerator pedal, the vehicle responds with driving force; when the driving force reaches a certain value, the EPB releases, releasing the braking output. During this process, the driving force needs to reach a value sufficient to prevent the vehicle from rolling backward.

[0056] It should be noted that the HHC's working process is as follows: During the process of the driver pressing the brake pedal to shift gears, the HHC is not triggered. When the driver releases the brake pedal, the HHC is triggered and controls the vehicle to maintain the original braking output that the vehicle had when the driver pressed the brake pedal. After maintaining the vehicle's braking output for a certain period of time, the HHC is released. During the time between the driver releasing the brake pedal and pressing the accelerator pedal, the vehicle maintains a braking output that can prevent the vehicle from rolling backwards.

[0057] Reference Figure 1 As shown, in step S100, the vehicle can use various sensors and algorithms to estimate the slope of the ramp it is on, such as using an Inertial Measurement Unit (IMU). It is understood that the IMU on the vehicle can measure acceleration, including longitudinal acceleration caused by the slope; by measuring the vehicle's acceleration (a) on the horizontal plane and taking into account gravitational acceleration (g), the sine value of the slope angle can be calculated; since there is a relationship between the slope angle (a) and the slope percentage (P): sin(a) = vertical height change / horizontal distance change, the slope angle can be estimated using the longitudinal acceleration (a) measured by the IMU sensor: sin(a) = a / p. Then, the sine value is converted into an angle, and the slope percentage is calculated: p = sin(a) × 100%.

[0058] Understandably, after obtaining the slope the vehicle is on, it's necessary to determine the magnitude of the slope, i.e., compare it with a preset slope range. The preset slope range represents the range where the vehicle has a risk of rolling back, and triggering HHC (Hardware Control) will bring the vehicle to a stop on the slope. This parameter is calibrated based on the actual vehicle model. For example, a slope less than 2% is defined as a slope with no risk of rolling back; a slope between 2% and 8% is defined as a slope with a risk of rolling back, where triggering HHC will bring the vehicle to a stop on that slope; and a slope greater than 8% is defined as a slope with a risk of rolling back, where triggering HHC will not bring the vehicle to a stop on that slope. Here, a 2% slope is understood as the slope's vertical height changing by 2 units for every 100 units of horizontal distance traveled. The same logic applies to other percentage slopes, which will not be elaborated upon here.

[0059] It is understandable that the absence of a risk of rolling back is interpreted as the vehicle not applying additional braking force and therefore not rolling back; the presence of a risk of rolling back, and the ability of HHC to stop the vehicle on the slope, is interpreted as the vehicle not applying additional braking force, and relying on HHC to control the vehicle to maintain the original braking output in response to the brake pedal, thus preventing the vehicle from rolling back.

[0060] Reference Figure 1As shown, in step S200, when it is determined that the slope of the ramp is within the preset slope range, that is, within the range of 2% to 8%, it is necessary to determine the driving direction of the vehicle and judge the relationship between the driving direction and the ramp, that is, to judge whether the driving direction is uphill or downhill. Only when the driving direction of the vehicle is uphill does it need to consider the problem of the vehicle rolling backward when starting. When the driving direction of the vehicle is downhill, it is not necessary to consider the problem of the vehicle rolling backward when starting.

[0061] Reference Figure 2 As shown, step S300 also includes, but is not limited to, the following steps:

[0062] Step S310: When the driving direction is downhill, control the EPB to switch to the first working mode.

[0063] Understandably, when a vehicle stops on a slope, either its front or rear faces uphill. Simultaneously, the vehicle can move forward or backward. When the front faces uphill, the vehicle shifts to drive and moves forward, traveling uphill; when the front faces uphill, the vehicle shifts to reverse and moves backward, traveling downhill. When the rear faces uphill, the vehicle shifts to drive and moves forward, traveling downhill; when the rear faces uphill, the vehicle shifts to reverse and moves backward, traveling uphill. When the vehicle is traveling downhill, the EPB (Electronic Brake Brake) can be released based on the driver's brake pedal input, resulting in faster vehicle acceleration.

[0064] Reference Figure 1 As shown, in step S300, when it is determined that the vehicle's driving direction is uphill, the vehicle's braking pressure is acquired and its relationship with the preset pressure is determined. The preset pressure is the braking force required to stop the vehicle on the slope without the risk of rolling back. This parameter is calibrated according to the actual vehicle model; for example, the preset pressure is calibrated to 120% of the braking pressure required to stop the vehicle on the slope. Since HHC only maintains the vehicle's braking output in response to the original driver pressing the brake pedal, if the vehicle's braking pressure is less than the preset pressure, the maintained braking output after HHC is triggered cannot guarantee that the vehicle will not roll back, posing a risk of rolling back. Therefore, before controlling the EPB to switch operating modes and triggering HHC, it is necessary to determine the magnitude of the vehicle's braking pressure at this time.

[0065] Reference Figure 1 As shown, in step S400, when it is determined that the vehicle's braking pressure is greater than or equal to the preset pressure, the EPB is controlled to switch to the first working mode. After the EPB is released, the HHC is triggered and the HHC assists the vehicle to start on the slope, so that the vehicle starts smoothly on the slope.

[0066] Reference Figure 3As shown, step S400 also includes, but is not limited to, the following steps:

[0067] Step S410: Obtain the driver's gear shifting action signal for the vehicle, and determine whether the gear shifting action is completed based on the gear shifting action signal;

[0068] Step S420: When the gear shifting action is completed, control EPB to release the braking output to the vehicle, activate HHC and control the vehicle to maintain braking output in response to the brake pedal.

[0069] Step S430: Obtain the driver's accelerator pedal depressing action signal, and determine whether the depressing action has started based on the depressing action signal;

[0070] Step S440: When the pedal action begins and the driving force output by the vehicle in response to the accelerator pedal meets the requirements for hill start, the HHC control over the vehicle is released, and the braking output of the vehicle in response to the brake pedal is released.

[0071] Understandably, in the first operating mode of EPB, after the vehicle shifts from park to drive or reverse (i.e., after exiting park), the EPB releases and disengages the braking output, activating HHC. After HHC activation, before the driver releases the brake pedal, HHC maintains the vehicle's braking output in response to the driver's brake pedal input for a certain period, such as 1.5 seconds, allowing sufficient time for the driver to depress the accelerator pedal and preventing rollback. After the driver depresses the accelerator pedal, the vehicle outputs driving force. When the driving force meets the requirements for starting on an incline, the HHC releases its control over the vehicle and disengages the braking output in response to the brake pedal input, achieving a smooth start. EPB, in conjunction with HHC, ensures a smooth and rollback-free start on an incline.

[0072] Reference Figure 4 As shown, step S420 also includes, but is not limited to, the following steps:

[0073] Step S421: The vehicle maintains braking output in response to the brake pedal for a preset time.

[0074] Step S422: When the preset time is exceeded or the driving force meets the requirements for hill start, HHC releases control of the vehicle, and the vehicle releases the braking output in response to the brake pedal.

[0075] Understandably, when HHC is triggered, the vehicle will remain stationary on the slope for 1.5 seconds to prevent rolling backward after EPB is released and the driver releases the brake pedal. There is a vacuum period between EPB release and the driver releasing the brake pedal and the driver pressing the accelerator pedal, during which HHC maintains the vehicle's braking effect. Once the preset time has elapsed or the driving force meets the requirements for starting on the slope, HHC is released, and the vehicle starts normally. During this process, there is no struggle between the braking force and the driving force, resulting in a smooth start.

[0076] Reference Figure 5 As shown, the parking brake control method of the first aspect of the present invention further includes, but is not limited to, the following steps:

[0077] Step S210: When the slope is less than the preset slope range, control the EPB to switch to the first working mode.

[0078] Step S220: Obtain the driver's gear shifting action signal for the vehicle, and determine whether the gear shifting action is completed based on the gear shifting action signal;

[0079] In step S230, when the gear shifting action is completed, the EPB is controlled to release the braking output to the vehicle.

[0080] Understandably, when the slope is less than the preset slope range, there is no risk of the vehicle rolling backwards. Therefore, the EPB can be directly switched to the first working mode, and the vehicle can be started by releasing the P gear using the EPB. A slope less than the preset slope range can be understood as the vehicle being on flat ground or a slight incline.

[0081] Reference Figure 6 As shown, the parking brake control method of the first aspect of the present invention further includes, but is not limited to, the following steps:

[0082] Step S240: When the slope is greater than the preset slope range, determine the relationship between the vehicle's driving direction and the slope.

[0083] Step S250: When the driving direction is uphill, control the EPB to switch to the second working mode. The second working mode is the working mode in which the EPB releases according to the driving force output by the vehicle in response to the accelerator pedal.

[0084] Understandably, when the slope exceeds the preset range, the vehicle risks rolling backwards, and triggering HHC (Hyperbratory Conduction Control) may not stop the vehicle on the slope. If EPB (Electronic Braking System) is switched to the first operating mode and HHC is triggered, the braking output maintained by HHC may not guarantee a safe start, meaning the vehicle might slip under gravity. Therefore, it's necessary to switch EPB to the second operating mode, where EPB is only released when the driving force is sufficient, preventing the vehicle from slipping and rolling backwards. A slope exceeding the preset range indicates the vehicle is on a steep slope.

[0085] Reference Figure 7 As shown, step S250 also includes, but is not limited to, the following steps:

[0086] Step S251: Control EPB to maintain braking output to the vehicle;

[0087] Step S252: Obtain the driver's accelerator pedal depressing action signal, and determine the magnitude of the driving force output by the vehicle in response to the depressing action based on the depressing action signal.

[0088] Step S253: When the driving force is greater than the preset driving force, control EPB to release the braking output to the vehicle. The preset driving force is the driving force that enables the vehicle to meet the requirements for starting on a slope.

[0089] Understandably, when the EPB is switched to the second operating mode, the vehicle prioritizes safety over smoothness. Therefore, after the driver releases the brake pedal, the EPB is still needed to maintain braking output to the vehicle, rather than the HHC maintaining the vehicle's response to the brake pedal. The EPB is only released when the vehicle's driving force reaches a certain value.

[0090] Reference Figure 8 As shown, the parking brake control device of the second aspect of the present invention includes an acquisition module, a first determination module, a second determination module, and an execution module. The acquisition module is configured to acquire the slope of the ramp where the vehicle is located and to acquire the vehicle's braking pressure. The first determination module is configured to determine whether the slope is within a preset slope range. When the slope is within the preset slope range, it determines the relationship between the vehicle's driving direction and the ramp based on the vehicle's driving direction. The preset slope range is a range where the vehicle has a risk of rolling back, and triggering the parking brake control (HHC) will stop the vehicle on the ramp. The second determination module is configured to, when the driving direction is uphill, determine the relationship between the braking pressure and a preset pressure based on the braking pressure. The preset pressure is the braking force required to stop the vehicle on the ramp without the risk of rolling back. The execution module is configured to, when the braking pressure is greater than or equal to the preset pressure, control the EPB to switch to a first operating mode and control the vehicle to trigger the parking brake control (HHC) based on the EPB's release signal.

[0091] Understandably, when a vehicle needs to start on a slope, the driver presses the brake pedal to shift gears. During this process, the acquisition module acquires the slope of the slope the vehicle is on, and the first determination module determines the magnitude of the slope. When the first determination module determines that the slope is within a preset slope range—that is, a slope where the vehicle is at risk of rolling back, and where triggering HHC can stop the vehicle on that slope—the first determination module determines the relationship between the vehicle's driving direction and the slope. When the first determination module determines that the vehicle's driving direction is uphill, the acquisition module acquires the vehicle's braking pressure. The second determination module, based on the braking pressure, determines the relationship between the braking pressure and a preset pressure. To ensure the vehicle stops on a slope without the risk of rolling backwards, when the second determining module determines that the braking pressure is greater than or equal to the preset pressure, the execution module controls the EPB to switch to the first operating mode and controls the vehicle to trigger HHC. The first operating mode is the EPB release mode when the driver depresses the brake pedal to shift gears (i.e., the EPB begins to release during the driver's shifting and is fully released when the driver completes the shift and depresses the accelerator pedal). After HHC is triggered, the vehicle starts with HHC assistance. By implementing the parking brake control method through the control device, the smoothness of the vehicle's start on the slope can be guaranteed, and the problem of the vehicle rolling backwards will not occur.

[0092] It should be noted that in some embodiments, when the first determining module determines that the slope is less than a preset slope range, the execution module controls the EPB to switch to a first operating mode. When the first determining module determines that the slope is greater than the preset slope range, the execution module controls the EPB to switch to a second operating mode. The second operating mode is an automatic release mode for the EPB, which responds to the vehicle's driving force; when the driving force is sufficiently large, the EPB is released. In the second operating mode of the EPB, vehicle safety is prioritized.

[0093] Reference Figure 9 The following describes a specific example of a control method according to a first aspect of an embodiment of the present invention, and one such example is illustrated below:

[0094] When the vehicle stops on the slope, the EPB is clamped. The acquisition module acquires the slope. The first determination module determines whether the slope is within 2%. If the first determination module determines that the slope is not within 2%, the acquisition module acquires the driver's gear shifting action information. The first determination module determines the vehicle's driving status based on the gear shifting action information. If the first determination module determines that the vehicle is in reverse gear and is going downhill, the first determination module determines whether the slope is within the range of 2% to 8%. If the first determination module determines that the slope is within the range of 2% to 8%, the acquisition module acquires the vehicle's braking pressure. The second determination module determines the magnitude of the braking pressure. If the second determination module determines that the braking pressure is greater than 120% of the braking force required for the vehicle to stop on the current slope, the execution module controls the EPB to release and controls the HHC to trigger. If the second determination module determines that the torque generated by the vehicle's driving force is sufficient for the vehicle to start on the slope, the HHC is released.

[0095] It should be noted that when the first determining module determines that the vehicle's driving state is uphill and the slope is greater than 8%, the vehicle's braking pressure can also be obtained first through the acquisition module. When the second determining module determines that the braking pressure is greater than 120% of the braking force required for the vehicle to stop on the current slope, the execution module controls the EPB to release and controls the HHC to trigger. That is, after determining that the vehicle's driving state is uphill and the slope is greater than 8%, there are two control routes to choose from. The first route is to control the EPB to switch to the second working mode; the second route is to determine the braking pressure and then control the EPB's working mode to either the first or second working mode based on the braking pressure. When the braking pressure is greater than 120% of the braking force required by the vehicle, the EPB is controlled to switch to the first working state and the HHC is triggered. When the braking pressure is less than 120% of the braking force required by the vehicle, the EPB is controlled to switch to the second working state.

[0096] In other words, under normal circumstances, when the gradient is greater than 8%, safety takes priority, so the EPB is directly switched to the second operating mode. However, for gradients greater than 8%, the EPB is not required to switch directly to the second operating mode; the vehicle's braking pressure can be assessed first, and then the EPB's operating mode can be determined.

[0097] The vehicle of the third aspect of this invention includes a memory, a processor, and a program stored in the memory and executable on the processor. When the program is executed by the processor, it implements the parking brake control method described above. For example, the processor and memory in the vehicle controller can be connected via a bus. The memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, the memory may include high-speed random access memory and non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may optionally include memory remotely located relative to the control processor, and these remote memories can be connected to the controller via a network.

[0098] The non-transient software program and instructions required to implement the control method of the above embodiments are stored in memory. When executed by a processor, the control method of the above embodiments is executed. For example, executing... Figure 1 Method steps S100 to S400 Figure 2 The method steps S310, etc.

[0099] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0100] It should be noted that the vehicle can be a private car, such as a sedan, SUV, MPV, or pickup truck. The vehicle can also be a commercial vehicle, such as a van, bus, small truck, or large semi-trailer. The vehicle must have an electric motor capable of outputting power or acting as a generator to store mechanical energy. When the vehicle is a new energy vehicle, it can be a hybrid vehicle or a pure electric vehicle.

[0101] The vehicle uses a control device to execute the above-mentioned parking brake control method, which can ensure that the vehicle starts smoothly on a slope and does not slip.

[0102] In the computer-readable storage medium of the fourth aspect of the present invention, the computer-readable storage medium stores computer-executable instructions, which are used to cause a computer to execute the above-described parking brake control method. Since the computer-readable storage medium can execute all the technical solutions of the above-described control method, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0103] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A parking brake control method, characterized in that, Applied to vehicles equipped with electronic parking brake systems and hill start assist systems, the parking brake control method includes the following steps: The slope of the ramp where the vehicle is located is obtained, and it is determined whether the slope is within a preset slope range. The preset slope range is the range within which the vehicle is at risk of rolling back and the ramp start assist system can stop the vehicle within the slope range. When the slope is within the preset slope range, the relationship between the driving direction and the slope is determined based on the driving direction of the vehicle. When the driving direction is uphill, the braking pressure of the vehicle is obtained, and the relationship between the braking pressure and the preset pressure is determined based on the braking pressure. The preset pressure is the braking force that stops the vehicle on the slope without the risk of rolling back. When the braking pressure is greater than or equal to the preset pressure, the electronic parking brake system is controlled to switch to the first working mode, and the vehicle is controlled to trigger the hill start assist system according to the signal that the electronic parking brake system has completed the release. The first working mode is the working mode in which the electronic parking brake system releases according to the driver's action of pressing the brake pedal. Acquire the driver's gear shifting action signal for the vehicle, and determine whether the gear shifting action is completed based on the gear shifting action signal; When the gear shifting action is completed, the electronic parking brake system is controlled to release the braking output to the vehicle, the hill start assist system is activated, and the vehicle is controlled to maintain the braking output in response to the brake pedal. Acquire the driver's accelerator pedal depress signal, and determine whether the depressing action has started based on the depressing signal; When the pedal action begins, and the driving force output by the vehicle in response to the accelerator pedal meets the hill start requirements, the hill start assist system releases control of the vehicle and releases the vehicle's braking output in response to the brake pedal.

2. The parking brake control method according to claim 1, characterized in that, The parking brake control method further includes the following steps: When the driving direction is downhill, the electronic parking brake system is switched to the first working mode.

3. The parking brake control method according to claim 1, characterized in that, Activating the hill start assist system and controlling the vehicle to maintain braking output responsive to the brake pedal further includes the step of: Control the vehicle to maintain braking output in response to the brake pedal for a preset time; When the preset time is exceeded or the driving force meets the hill start requirements, the hill start assist system releases control of the vehicle and releases the vehicle's braking output in response to the brake pedal.

4. The parking brake control method according to claim 1, characterized in that, The parking brake control method further includes the following steps: When the slope is less than the preset slope range, the electronic parking brake system is controlled to switch to the first working mode; Acquire the driver's gear shifting action signal for the vehicle, and determine whether the gear shifting action is completed based on the gear shifting action signal; When the gear shifting action is completed, the electronic parking brake system releases its braking output on the vehicle.

5. The parking brake control method according to claim 1, characterized in that, The parking brake control method further includes the following steps: When the slope is greater than the preset slope range, determine the relationship between the vehicle's driving direction and the slope. When the driving direction is uphill, the electronic parking brake system is switched to the second working mode. The second working mode is the working mode in which the electronic parking brake system releases the brake according to the driving force output by the vehicle in response to the accelerator pedal.

6. The parking brake control method according to claim 5, characterized in that, The step of controlling the electronic parking brake system to switch to the second operating mode includes: Control the electronic parking brake system to maintain braking output on the vehicle; The driver's accelerator pedal depressing signal is acquired, and the magnitude of the driving force output by the vehicle in response to the accelerator pedal is determined based on the depressing signal. When the driving force is greater than the preset driving force, the electronic parking brake system releases its braking output on the vehicle. The preset driving force is the driving force that enables the vehicle to meet the requirements for starting on a slope.

7. A parking brake control device, characterized in that, For performing the parking brake control method as described in any one of claims 1 to 6, the control device includes: The acquisition module is configured to acquire the slope of the ramp where the vehicle is located, and to acquire the braking pressure of the vehicle. The first determining module is configured to determine whether the slope is within a preset slope range based on the slope. When the slope is within the preset slope range, the module determines the relationship between the driving direction and the slope based on the driving direction of the vehicle. The preset slope range indicates that the vehicle is at risk of rolling back, and triggering the slope start assist system can stop the vehicle within the slope range of the slope. The second determining module is configured to determine the relationship between the braking pressure and a preset pressure based on the braking pressure when the driving direction is uphill. The preset pressure is the braking force that stops the vehicle on the slope without the risk of rolling back. The execution module is configured to control the electronic parking brake system to switch to a first working mode when the braking pressure is greater than or equal to the preset pressure, and to control the vehicle to trigger the hill start assist system according to the signal that the electronic parking brake system has completed release.

8. A vehicle, characterized in that, It includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the parking brake control method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the parking brake control method as described in any one of claims 1 to 6.

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