A vehicle speed control method, storage medium and vehicle

Abstract

The application provides a vehicle speed control method, a storage medium and a vehicle, and relates to the technical field of vehicle speed control, and comprises the following steps: obtaining a driver operation signal and vehicle parameter information; determining a target speed and a target brake torque of the vehicle based on the driver operation signal and the vehicle parameter information; determining a vehicle state based on the driver operation signal and the vehicle parameter information; and controlling a driving motor and an EPB to output brake torque based on the vehicle state, the target brake torque and brake capacity of the driving motor and the EPB. Through the above arrangement, the driving motor and the EPB are cooperatively controlled to output brake torque, so that the driving safety of the vehicle in different driving states is ensured.

Description

Technical Field

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

[0002] With the popularization and promotion of new energy vehicles, electric drive technology is being used more and more widely in the automotive field. However, due to imperfect speed control, accidents often occur due to excessively sudden or insufficient braking. Furthermore, for electric vehicles, braking during operation typically relies on the drive motor, and the braking capacity of the drive motor is insufficient to meet the driver's safety requirements. In addition, existing new energy vehicles are usually equipped with electronic parking brake systems, which use a power unit to pull a mechanical cable to park the vehicle. Electronic parking brake systems can output significant braking force to meet parking requirements.

[0003] Although the braking capacity of the drive motor is limited, it can precisely control the braking torque; the electronic parking brake system has the ability to output a large braking torque, but its braking torque control accuracy is poor. In existing technologies, EPB (Electronic Parking Brake) and drive motor are typically used in tandem braking during vehicle start-up to prevent the vehicle from rolling backward. For example, patent CN112265544A discloses a new energy vehicle anti-rollback auxiliary control method. This method discloses that when the anti-rollback system identifies a starting rollback condition, it controls the motor to output stall torque for anti-rollback. When the drive motor anti-rollback timeout expires or the electric drive system fails to maintain the anti-rollback stall torque, and the vehicle has not started, or the brakes are applied, or the handbrake is engaged, the vehicle stability controller controls the brake actuator to output service braking force for anti-rollback. When the anti-rollback system identifies that the vehicle stability controller anti-rollback timeout has expired and the vehicle has not yet applied the brakes or engaged the handbrake, it controls the electronic parking controller to maintain parking, and the electronic parking controller controls the brake actuator to continue outputting mechanical braking force for parking. When the driver starts the vehicle, applies the brakes, or engages the handbrake, the system automatically releases the drive motor stall torque or mechanical braking force. However, since the vehicle starts at a low speed, the EPB is relatively easy to control, and there is currently no technical solution that applies the coordinated braking of the EPB and the drive motor to the vehicle when it is in motion. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a vehicle speed control method, a storage medium, and a vehicle. By collecting driver operation signals and vehicle parameter information, the target speed and target braking torque are calculated. Based on the vehicle state, a coordinated braking mode of EPB and drive motor under different vehicle states is formulated, thereby improving braking safety and comfort.

[0005] A first aspect of the present invention provides a vehicle speed control method, comprising: acquiring driver operation signals and vehicle parameter information; determining a target speed and a target braking torque of the vehicle based on the driver operation signals and vehicle parameter information; determining a vehicle state based on the driver operation signals and vehicle parameter information; and controlling the drive motor and EPB to output braking torque based on the vehicle state, the target braking torque, and the braking capabilities of the drive motor and EPB.

[0006] In one possible implementation, the driver operation signal includes throttle opening, throttle opening rate of change, brake pedal opening, gear signal, electronic parking brake signal, and brake pedal opening rate of change; the vehicle parameter information includes real-time vehicle speed, maximum braking torque of the drive motor, maximum braking power, current speed of the drive motor temperature, cumulative braking time of the drive motor, and battery SOC.

[0007] In one possible implementation, when the real-time vehicle speed is less than a first preset speed and the electronic parking brake signal is true, the EPB activates the parking function.

[0008] In one possible implementation, when the vehicle moves forward, the real-time vehicle speed is greater than a second preset speed, the brake pedal opening change rate is greater than a first set value, and the brake pedal opening is maintained within a set threshold range for a period exceeding a first preset time, and the target braking torque is greater than the current maximum braking torque of the drive motor, the drive motor is controlled to output the current maximum braking torque; when the vehicle moves forward, and the real-time vehicle speed is less than the second preset speed within a second preset time or the cumulative braking time of the drive motor exceeds the second preset time, the EPB is controlled to output the target braking torque with a first torque amplification.

[0009] In one possible implementation, when the vehicle moves forward, the real-time vehicle speed is greater than a second preset speed, the brake pedal opening change rate is greater than a first set value, and the brake pedal opening is maintained within a set threshold range for a period of time exceeding a first preset time, the target braking torque is less than the current maximum braking torque of the drive motor, and the drive motor is controlled to output the target braking torque.

[0010] In one possible implementation, when the vehicle moves forward, the real-time vehicle speed is less than a second preset speed but greater than a third preset speed, the brake pedal opening change rate is greater than a first set value, and the brake pedal opening is maintained within a set threshold range for a period of time exceeding a first preset time. If the target braking torque is greater than the current braking torque of the drive motor, the drive motor is controlled to output the current maximum braking torque, and the EPB is controlled to output the remaining braking torque with a second torque amplification.

[0011] In one possible implementation, when the vehicle moves forward, the rate of change of the brake pedal opening is greater than a first set value, and the time during which the brake pedal opening is within the set threshold range is less than a first preset time, the drive motor is controlled to output a portion of the maximum braking torque in a certain proportion.

[0012] In one possible implementation, when the vehicle is moving backward and the real-time vehicle speed is greater than a fourth preset speed, if the electronic handbrake signal is true or the gear signal is N, then the EPB is controlled to activate the parking function.

[0013] In one possible implementation, when the vehicle moves backward and the real-time vehicle speed is not greater than the fifth preset speed, the gear signal is N. If the target braking torque is less than the current maximum braking torque of the drive motor, the drive motor is controlled to output the target braking torque. If the cumulative braking time of the drive motor exceeds the third preset time or the current maximum braking torque of the drive motor is less than the target braking torque within the third preset time, the EPB is controlled to start the parking function.

[0014] A second aspect of the present invention provides a readable storage medium for storing a program, which, when executed, is used to implement the above-described vehicle speed control method.

[0015] A fourth aspect of the present invention provides a vehicle that employs the above-described vehicle speed control method or a readable storage medium.

[0016] This invention provides a vehicle speed control method, storage medium, and vehicle. First, it acquires driver operation signals and vehicle parameter information. Based on these signals, it determines the vehicle's target speed and target braking torque. Then, it determines the vehicle's state based on the same signals and parameters. Finally, based on the vehicle state, the target braking torque, and the braking capabilities of the drive motor and EPB, it controls the drive motor and EPB to output braking torque. This solution first obtains the target speed and target braking torque based on driver operation and specific vehicle parameters. Secondly, it considers the vehicle's operating state and the braking capability of the braking mechanism. It takes into account the characteristics of the drive motor (high braking torque control accuracy but low braking torque) and the EPB (low braking torque control accuracy but high braking torque), and proposes a reasonable coordinated control method for the drive motor and EPB based on the vehicle's operating state, thereby improving driving comfort and safety. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the vehicle speed control method provided in Embodiment 1 of the present invention;

[0019] Figure 2 This is a graph showing the relationship between battery coefficient and SOC provided in Embodiment 1 of the present invention;

[0020] Figure 3 This is a temperature coefficient versus temperature relationship diagram provided in Embodiment 1 of the present invention;

[0021] Figure 4 This is a flowchart of a vehicle speed control method for forward movement provided in Embodiment 2 of the present invention;

[0022] Figure 5 This is a flowchart of a vehicle speed control method for when the real-time vehicle speed is less than a first preset speed, provided in Embodiment 2 of the present invention.

[0023] Figure 6 This is a flowchart of a vehicle speed control method for backward movement provided in Embodiment 2 of the present invention; Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] In this invention, the EPB (Electronic Park Brake) system uses a power unit to pull a mechanical cable, which in turn pulls the wheel brake discs, thereby braking or parking the vehicle.

[0027] Example 1

[0028] Figure 1 This invention provides a vehicle speed control method, comprising:

[0029] S11 acquires driver operation signals and vehicle parameter information. The driver operation signals include throttle opening, throttle opening change rate, brake pedal opening, gear position signal, electronic parking brake signal, and brake pedal opening change rate; the vehicle parameter information includes real-time vehicle speed, maximum braking torque of the drive motor, maximum braking power, current speed and drive motor temperature, cumulative braking time of the drive motor, and battery SOC; the gear position signal includes D, R, P, and N.

[0030] S12 determines the target speed and target braking torque of the vehicle based on the driver's operation signal and vehicle parameter information.

[0031] Specifically, the target velocity v des The result is obtained through the following formula:

[0032]

[0033] In the formula, δ is the direction coefficient, which is 1 for D mode, -1 for R mode, and 0 for N mode; The driver's intention equation is expressed as follows: throttle opening α and rate of change of throttle opening. Brake pedal opening β, brake pedal opening rate of change Related; The velocity equation is related to the throttle opening α and the rate of change of the throttle opening. Brake pedal opening β, brake pedal opening rate of change and the velocity v at the previous moment c Related.

[0034] The required braking torque T of the vehicle des The result is obtained through the following formula:

[0035]

[0036] In the formula, t(v c v des The equation for torque is given by the velocity v at the previous moment. c and target speed v des Related.

[0037] S13 determines the vehicle status based on the driver's operation signals and vehicle parameter information.

[0038] Specifically, the vehicle state includes forward movement, backward movement, and a real-time speed less than a first preset speed. The first preset speed is a very low vehicle speed, such as 4 km / h, which is sufficient for gear shifting, gear changing, or braking. Forward movement is defined as a real-time speed greater than 4 km / h and forward movement; backward movement is defined as a real-time speed greater than 4 km / h and backward movement; when the speed is not greater than 4 km / h, the real-time speed is less than the first preset speed. When the vehicle is moving forward, its speed is further divided into a second preset speed and a third preset speed, where the second preset speed is greater than the third preset speed. When the real-time speed exceeds the second preset speed, the vehicle speed is high, and even small changes in torque or fluctuations in torque distribution can lead to significant changes in the vehicle state. For example, the second preset speed can range from 90 km / h to 120 km / h. When the real-time speed is less than the second preset speed but greater than the third preset speed, the vehicle speed is relatively high, but it can withstand a certain amount of torque fluctuation. The third preset speed can range from 30 to 40 km / h.

[0039] S14 controls the output braking torque of the drive motor and EPB based on the vehicle status, target braking torque, and braking capabilities of the drive motor and EPB.

[0040] Specifically, the braking capacity of the drive motor, i.e., the current maximum braking torque of the drive motor. The following formula can be used for calculation:

[0041]

[0042] Among them, T max P is the maximum braking torque of the drive motor. max Let λ1 be the maximum braking power of the drive motor, λ2 be the battery coefficient, λ2 be the temperature coefficient, and n be the drive motor speed. The maximum braking torque of the drive motor can be calculated using this formula. The values ​​of λ1 and λ2 can be selected according to... Figure 2 and 3 Make a selection.

[0043] The EPB can generate significant braking force during braking, but its torque control precision is relatively poor. Under safe conditions, the maximum torque that the EPB can output is its maximum braking torque. In this embodiment, based on the vehicle's environment, the torque amplification of the EPB is divided into a first torque amplification and a second torque amplification. These two torque amplifications, within their respective speed limits, are designed to ensure vehicle safety, and their values ​​are determined by the vehicle's inherent characteristics, such as its mass, tire friction, and speed.

[0044] Specifically, when the real-time vehicle speed is less than the first preset speed and the electronic parking brake signal is true, the EPB activates the parking function. At this time, the real-time vehicle speed is low, and when the electronic parking brake signal is available, the EPB can be directly driven to activate the parking function, that is, a large torque is applied to the EPB to lock the wheels through the mechanical cable.

[0045] When the vehicle moves forward, if the real-time vehicle speed is greater than the second preset speed, the brake pedal opening change rate is greater than the first set value, and the brake pedal opening is maintained within the set threshold range for more than the first preset time, and the target braking torque is greater than the current maximum braking torque of the drive motor, the drive motor is controlled to output the current maximum braking torque; when the vehicle moves forward, if the real-time vehicle speed is less than the second preset speed or the cumulative braking time of the drive motor exceeds the second preset time within the second preset time, the EPB is controlled to output the target braking torque with a first torque amplification. If the rate of change of brake pedal opening is greater than a first set value and the brake pedal opening is within a set threshold range for a duration exceeding a first preset time, it can be understood as the driver applying emergency braking and maintaining the brakes for an extended period to confirm the driver's intention to brake. When the real-time vehicle speed is greater than a second preset speed and the target braking torque is large, braking with the drive motor alone is insufficient to meet the current situation. At this time, the vehicle speed is relatively high, and a hasty intervention of the EPB could have a significant impact on vehicle safety due to even a small change in its torque value. Therefore, the drive motor is first controlled to output the current maximum braking torque. When the real-time vehicle speed decreases to the second preset speed within a second preset time, EPB intervention will not cause any driving safety issues. The target braking torque is then output by the EPB with a first torque amplification, or if the cumulative braking time of the drive motor exceeds the second preset time, it indicates that the braking of the drive motor is no longer sufficient to meet vehicle safety requirements. Therefore, the EPB outputs the target braking torque with a first torque amplification to prevent further safety problems.

[0046] It should be noted that the first preset time is a duration determined by ergonomics based on the driver's driving habits, and its value ranges from 1 second. The second preset time is for emergency situations where, within the preset time, the drive motor cannot reduce the real-time vehicle speed to below the second preset speed, but continuing to use the drive motor for braking would damage the drive motor itself or fail to meet safe driving conditions. In this embodiment, the brake pedal opening is within a set threshold range, preferably 80%-100%.

[0047] When the vehicle moves forward, if the real-time vehicle speed is greater than a second preset speed, the rate of change of the brake pedal opening is greater than a first preset value, and the brake pedal opening is maintained within a set threshold range for a period exceeding a first preset time, and the target braking torque is less than the current maximum braking torque of the drive motor, the drive motor is controlled to output the target braking torque. At this time, the drive motor's braking meets the target braking torque, therefore the drive motor can be controlled to output the target braking torque via the MCU (Motor Control Unit).

[0048] When the vehicle moves forward, if the real-time vehicle speed is less than a second preset speed but greater than a third preset speed, the brake pedal opening change rate is greater than a first preset value, and the brake pedal opening is maintained within a set threshold range for more than a first preset time, and if the target braking torque is greater than the current braking torque of the drive motor, the drive motor is controlled to output the current maximum braking torque, and the EPB is controlled to output the remaining braking torque with a second torque amplification. In the above vehicle state, the EPB intervention conditions are met. However, since the drive motor and EPB work together to brake the vehicle, the EPB outputs the remaining braking torque with a second torque amplification. The reason for using a second torque amplification is to prevent excessively rapid torque amplification, which could lead to large torque fluctuations. Furthermore, in conjunction with the drive motor's braking torque, this improves driving safety and braking performance. The remaining braking torque is the target braking torque minus the current maximum braking torque of the drive motor.

[0049] It should be noted that the aforementioned "first torque increase" and "second torque increase" refer to the torque increase rates adopted to meet driving requirements. Regarding the first torque increase, it refers to the torque increase used by the EPB (Electronic Power Brake) when driving safety is met due to the use of EPB for independent braking; the second torque increase is the torque increase allowed to meet both driving safety and the synergistic braking effect with the drive motor. In this embodiment of the invention, the first torque increase is 5 Nm / ms, and the second torque increase is 10 Nm / ms.

[0050] When the vehicle moves forward, if the rate of change of the brake pedal opening exceeds a first set value, and the duration for which the brake pedal opening remains within a set threshold range is less than a first preset time, the drive motor is controlled to output a portion of the maximum braking torque in a certain proportion. In this vehicle state, because the duration is less than the first preset time, there is a possibility of driver error. In this case, EPB intervention is unnecessary. However, to prevent accidents, the drive motor is controlled to output a portion of the maximum braking torque in a certain proportion. In this embodiment, the proportion is 10%-40%, preferably 30%.

[0051] When the vehicle moves backward, if the real-time vehicle speed is greater than the fourth preset speed, and the electronic handbrake signal is true or the gear signal is N, then the EPB is controlled to activate the parking function.

[0052] When the vehicle moves backward, if the real-time vehicle speed is not greater than the fifth preset speed, the gear signal is N. If the target braking torque is less than the current maximum braking torque of the drive motor, the drive motor is controlled to output the target braking torque. If the cumulative braking time of the drive motor exceeds the third preset time or if the current maximum braking torque of the drive motor is less than the target braking torque within the third preset time, the EPB is controlled to start the parking function.

[0053] It should be noted that when the vehicle moves backward, its actual speed is relatively low. For example, if the vehicle is rolling backward on a slope, and the real-time speed is greater than the fourth preset speed, the electronic parking brake signal is true, or the gear signal is N, then the EPB will be directly controlled to activate the parking function to prevent dangerous driving. On the other hand, when the real-time speed is not greater than the fifth preset speed, the gear signal is N, and the braking torque is less than the current maximum braking torque of the drive motor, the drive motor can be controlled to output the target torque. When the drive motor stalls for more than the third preset time, indicating that the drive motor is overheating or the driver has been away from the vehicle for an extended period with the intention of parking for a long time, the EPB will be activated to activate the parking function. Alternatively, if the battery power is depleted within the second preset time, causing the current maximum braking torque of the drive motor to decrease and making it difficult to meet the vehicle's parking requirements, the EPB will be activated to activate the parking function.

[0054] The aforementioned "fourth preset speed" is for a relatively high vehicle speed, where the EPB can quickly brake the vehicle without the need for the drive motor to intervene in braking. The "fifth preset speed" is based on a lower vehicle speed, where the target braking torque is less than the drive motor's current maximum braking torque. In this case, the drive motor is controlled to output the target braking torque. This corresponds to a scenario where the vehicle speed is very low, and the drive motor braking is used to meet the braking requirements, facilitating the driver's need for short-term stopping. The fourth or fifth preset speed is selected based on different vehicle models, and its specific value range is not limited here. Furthermore, it is obvious that the fourth and fifth preset speeds are greater than the first preset speed.

[0055] This embodiment also provides a readable storage medium for storing the above-described program, which, when executed, is used to implement the above-described vehicle speed control method.

[0056] The memory 1110 may include random access memory (RAM) or read-only memory (ROM). The memory 1110 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 1110 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as histogram equalization), instructions for implementing the various method embodiments described below, etc. The data storage area may also store data created by the electronic device 1100 during use (such as image matrix data).

[0057] The present invention also provides a vehicle that employs the above-described speed control method or the above-described readable storage medium.

[0058] Example 2

[0059] Embodiment 2 of the present invention provides a vehicle speed control flowchart, including:

[0060] S21 acquires driver operation signals and vehicle parameter information. The driver operation signals include throttle opening, throttle opening change rate, brake pedal opening, gear position signal, electronic parking brake signal, and brake pedal opening change rate; the vehicle parameter information includes real-time vehicle speed, maximum braking torque of the drive motor, maximum braking power, current speed and drive motor temperature, cumulative braking time of the drive motor, and battery SOC; the gear position signal includes D, R, P, and N.

[0061] S22 determines the target speed and target braking torque of the vehicle based on the driver's operation signal and vehicle parameter information.

[0062] Specifically, the target velocity v des The result is obtained through the following formula:

[0063]

[0064] In the formula, δ is the direction coefficient, which is 1 for D mode, -1 for R mode, and 0 for N mode; The driver's intention equation is expressed as follows: throttle opening α and rate of change of throttle opening. Brake pedal opening β, brake pedal opening rate of change Related; The velocity equation is related to the throttle opening α and the rate of change of the throttle opening. Brake pedal opening β, brake pedal opening rate of change and the velocity v at the previous moment c Related.

[0065] The required braking torque T of the vehicle des The result is obtained through the following formula:

[0066]

[0067] In the formula, t(v c v des The equation for torque is given by the velocity v at the previous moment. c and target speed v des Related.

[0068] S23 determines the vehicle status based on the driver's operation signals and vehicle parameter information;

[0069] The vehicle states include forward movement, backward movement, and real-time speed less than a first preset speed. The first preset speed is a very low vehicle speed, such as 4 km / h, which is sufficient for gear shifting, gear changing, or braking. Forward movement is defined as a real-time speed greater than 4 km / h and forward movement; backward movement is defined as a real-time speed greater than 4 km / h and backward movement; when the speed is not greater than 4 km / h, the real-time speed is less than the first preset speed. When the vehicle is moving forward, its speed is further divided into a second preset speed and a third preset speed, with the second preset speed being greater than the third preset speed. When the real-time speed exceeds the second preset speed, the vehicle speed is high, and even small changes in torque or fluctuations in torque distribution can lead to significant changes in the vehicle state. For example, the second preset speed can range from 90 km / h to 120 km / h. When the real-time speed is less than the second preset speed but greater than the third preset speed, the vehicle speed is relatively high, but it can withstand a certain amount of torque fluctuation. The third preset speed can range from 30 to 40 km / h.

[0070] S24 controls the drive motor and EPB to output braking torque based on the vehicle status, target braking torque, and braking capabilities of the drive motor and EPB.

[0071] Specifically, S23 determines the vehicle's driving direction, which includes the vehicle moving forward S231, the real-time vehicle speed being less than the first preset speed S232, and the vehicle moving backward S233.

[0072] like Figure 4 As shown, in step S231, when the vehicle moves forward, it is determined whether the real-time vehicle speed is greater than the second preset speed.

[0073] If yes, then determine whether the rate of change of brake pedal opening is greater than the first set value; if yes, then determine whether the time during which the brake pedal opening is within the set threshold range exceeds the first preset time; if no, then end.

[0074] If the brake pedal opening is within the set threshold range and the holding time does not exceed the first preset time, the drive motor is controlled to output a portion of the maximum braking torque in a certain proportion. In this embodiment of the invention, the proportion is 10%-40%, preferably 30%.

[0075] If the brake pedal opening is held within the set threshold range for a period of time exceeding the first preset time, it is determined whether the target braking torque is greater than the current maximum braking torque of the drive motor. If not, the drive motor is controlled to output the target braking torque and the process ends. If so, the drive motor is controlled to output the current maximum braking torque.

[0076] Then, it is determined whether the real-time vehicle speed is less than the second preset speed or whether the braking time exceeds the second preset time within the second preset time; otherwise, monitoring continues; if so, the EPB is controlled to output the target braking torque with the first torque amplification and the process ends.

[0077] When the real-time vehicle speed is less than the second preset speed, determine whether the real-time vehicle speed is greater than the third preset speed; if not, end; if yes, determine whether the brake pedal opening change rate is greater than the first set value; if yes, determine whether the brake pedal opening is maintained within the set threshold range for more than the first preset time; if not, end.

[0078] If the brake pedal opening is within the set threshold range and the holding time does not exceed the first preset time, the drive motor is controlled to output the current maximum braking torque and the process ends.

[0079] If the brake pedal opening is within the set threshold range and the holding time exceeds the first preset time, it is determined whether the target braking torque is greater than the current maximum braking torque of the drive motor. If not, the drive motor is controlled to output the target braking torque and the process ends. If so, the drive motor is controlled to output the current maximum braking torque, and the EPB is controlled to output the remaining braking torque with the second torque amplification and the process ends.

[0080] If the real-time vehicle speed is less than the first preset speed S32, such as Figure 5 As shown, the EPB activates the parking function.

[0081] The vehicle moves backward S33, such as Figure 6 As shown, determine whether the real-time vehicle speed is greater than the fourth preset speed; if not, end; if yes, determine whether the electronic handbrake signal is true or whether the gear signal is N.

[0082] If not, the process ends; if the electronic parking brake signal is true or the gear signal is N, the EPB is controlled to activate the parking function and the process ends.

[0083] Determine if the real-time vehicle speed is less than the fifth preset speed; if not, end; if so, determine if the gear signal is N.

[0084] If the gear signal is N, then determine whether the target braking torque is greater than the current maximum braking torque of the drive motor; if the gear signal is not N, then end.

[0085] When the target braking torque is greater than the current maximum braking torque of the drive motor, the EPB is controlled to start and end the parking function; when the target braking torque is not greater than the current maximum braking torque of the drive motor, the drive motor is controlled to output the target braking torque.

[0086] Then, it is determined whether the current maximum braking torque of the drive motor is less than the target torque or whether the cumulative braking time of the drive motor exceeds the third preset time within the third preset time. If yes, the EPB is controlled to start the parking function and end; if no, monitoring continues.

[0087] This embodiment also provides a readable storage medium for storing the above-described program, which, when executed, is used to implement the above-described vehicle speed control method.

[0088] The memory 1110 may include random access memory (RAM) or read-only memory (ROM). The memory 1110 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 1110 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as histogram equalization), instructions for implementing the various method embodiments described below, etc. The data storage area may also store data created by the electronic device 1100 during use (such as image matrix data).

[0089] The present invention also provides a vehicle that employs the above-described speed control method or the above-described readable storage medium.

[0090] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vehicle speed control method, characterized in that, include: Acquire driver operation signals and vehicle parameter information; Based on the driver's operation signals and vehicle parameter information, the target speed and target braking torque of the vehicle are determined; The vehicle status is determined based on the driver's operation signals and vehicle parameter information. Based on the vehicle status, target braking torque, and braking capabilities of the drive motor and EPB, control the output braking torque of the drive motor and EPB. When the vehicle moves forward, the real-time vehicle speed is greater than the second preset speed, the brake pedal opening change rate is greater than the first set value, and the brake pedal opening is maintained within the set threshold range for more than the first preset time, and the target braking torque is greater than the current maximum braking torque of the drive motor, the drive motor is controlled to output the current maximum braking torque. When the vehicle moves forward, if the real-time vehicle speed is less than the second preset speed or the cumulative braking time of the drive motor exceeds the second preset time within a second preset time, the EPB is controlled to output the target braking torque with the first torque amplification. When the vehicle moves forward, if the real-time vehicle speed is less than the second preset speed but greater than the third preset speed, the brake pedal opening change rate is greater than the first set value, and the brake pedal opening is maintained within the set threshold range for more than the first preset time, and if the target braking torque is greater than the current braking torque of the drive motor, the drive motor is controlled to output the current maximum braking torque, and the EPB is controlled to output the remaining braking torque with the second torque amplification.

2. The control method according to claim 1, characterized in that, The driver operation signals include throttle opening, throttle opening change rate, brake pedal opening, gear signal, electronic parking brake signal, and brake pedal opening change rate; the vehicle parameter information includes real-time vehicle speed, maximum braking torque of the drive motor, maximum braking power, current speed and drive motor temperature, cumulative braking time of the drive motor, and battery SOC.

3. The control method according to claim 2, characterized in that, When the real-time vehicle speed is less than the first preset speed and the electronic handbrake signal is true, the EPB will activate the parking function.

4. The control method according to claim 2, characterized in that, When the vehicle moves forward, if the real-time vehicle speed is greater than the second preset speed, the brake pedal opening change rate is greater than the first set value, and the brake pedal opening is maintained within the set threshold range for a longer than the first preset time, and the target braking torque is less than the current maximum braking torque of the drive motor, the drive motor is controlled to output the target braking torque.

5. The control method according to claim 2, characterized in that, When the vehicle moves forward, if the rate of change of the brake pedal opening is greater than the first set value, and the time during which the brake pedal opening remains within the set threshold range is less than the first preset time, the drive motor is controlled to output a portion of the maximum braking torque in a certain proportion.

6. The control method according to claim 2, characterized in that, When the vehicle moves backward, if the real-time vehicle speed is greater than the fourth preset speed, and the electronic handbrake signal is true or the gear signal is N, then the EPB is controlled to start the parking function. When the vehicle moves backward, if the real-time vehicle speed is not greater than the fifth preset speed, the gear signal is N. If the target braking torque is less than the current maximum braking torque of the drive motor, the drive motor is controlled to output the target braking torque. If the cumulative braking time of the drive motor exceeds the third preset time or if the current maximum braking torque of the drive motor is less than the target braking torque within the third preset time, the EPB is controlled to start the parking function.

7. A readable storage medium, characterized in that, Used to store a program, which, when executed, is used to implement the vehicle speed control method according to any one of claims 1-6.

8. A vehicle that employs the speed control method according to any one of claims 1-6 or the readable storage medium according to claim 7.

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