A vehicle speed control method and a vehicle speed control system
By acquiring the load status and gradient of the electric vehicle, the target output slope of the motor torque and the maximum allowable vehicle speed are determined, which solves the problem of unstable vehicle speed under torque control mode, realizes stable control and energy consumption optimization, and improves user experience and range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SANY MARINE HEAVY INDUSTRY CO LTD
- Filing Date
- 2024-01-31
- Publication Date
- 2026-06-12
AI Technical Summary
The torque control methods of existing electric vehicles cause unstable acceleration when the vehicle's weight changes, making it impossible to effectively limit the vehicle speed, resulting in a poor driving experience and excessive energy consumption.
By acquiring the vehicle's load status and the slope of the road surface, the target output slope of the motor torque and the maximum allowable vehicle speed are determined, and these are correlated with the accelerator pedal to achieve stable control of the vehicle speed. Energy consumption is optimized by combining the motor regenerative braking method.
It achieves stable speed control under different load and gradient conditions, improves the operating experience, reduces energy consumption, and enhances the vehicle's driving range.
Smart Images
Figure CN117863902B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electric vehicle control technology, specifically to a vehicle speed control method and a vehicle speed control system. Background Technology
[0002] Electric vehicles that use torque control have their acceleration rate controlled solely by the slope of the output torque.
[0003] However, this control method has many drawbacks. For example, for vehicles whose weight changes frequently due to loading and unloading of goods and transportation of personnel, taking electric trucks as an example, if the torque control slope is too small, the vehicle will accelerate too slowly when loaded and will not be able to climb hills. If the torque output slope is too large, the vehicle will accelerate too quickly when lightly loaded or unloaded, resulting in a poor driving experience. Without limiting the vehicle speed according to the throttle opening, the vehicle speed will continue to rise to the maximum value when the throttle opening is small. When the vehicle speed is high, it is not possible to maintain a constant speed by adjusting the throttle pedal opening, which can easily lead to repeated acceleration and deceleration and excessive energy consumption. Furthermore, on downhill sections, the vehicle speed is relatively high when fully loaded, which poses a certain degree of danger. Summary of the Invention
[0004] In view of this, the present invention provides a vehicle speed control method and a vehicle speed control system, which determines the target output slope of the motor torque and the maximum permissible vehicle speed based on the vehicle's load state and the slope of the road surface, thereby achieving stable control of the vehicle speed, ensuring smooth driving, reducing energy consumption, and improving the user experience.
[0005] In a first aspect, the present invention provides a vehicle speed control method, comprising:
[0006] Obtain the vehicle's load status and the gradient of the road surface;
[0007] The maximum permissible speed of the vehicle is determined based on the load status, and the maximum permissible speed is associated with the accelerator pedal of the vehicle.
[0008] Based on the slope and the load condition, determine the target output slope of the motor torque of the vehicle's drive motor;
[0009] Wherein, the target output slope is the slope that causes the vehicle's speed to change according to a preset acceleration;
[0010] Based on the target output slope and the accelerator pedal opening, a motor torque command is output to the vehicle's motor controller.
[0011] In one possible implementation, obtaining the vehicle's load status and the slope of the road surface includes:
[0012] Obtain the vehicle tilt angle and target motor torque of the vehicle;
[0013] Wherein, the target motor torque is the motor torque corresponding to the change of the driving motor speed from 0 to the preset speed when the vehicle is started;
[0014] The slope of the road surface is determined based on the vehicle tilt angle.
[0015] Based on the slope and the target motor torque, determine the actual motor torque used for starting the vehicle;
[0016] Among multiple preset torque ranges, determine the target torque range to which the actual motor torque belongs;
[0017] Based on the first preset mapping relationship, the load state corresponding to the target torque range is determined;
[0018] The first preset mapping relationship records the correspondence between each preset torque range and different load states.
[0019] In one possible implementation, determining the actual motor torque for starting the vehicle based on the slope and the target motor torque includes:
[0020] The slope resistance during vehicle startup is determined based on the slope and the target motor torque.
[0021] The difference between the target motor torque and the slope resistance is calculated to obtain the actual motor torque used for starting the vehicle.
[0022] In one possible implementation, determining the maximum permissible speed of the vehicle based on the load state includes:
[0023] Based on the second preset mapping relationship, the maximum permissible vehicle speed corresponding to the load state of the vehicle is determined;
[0024] The second preset mapping relationship records the correspondence between the maximum allowable vehicle speed and different load states.
[0025] In one possible implementation, determining the target output slope of the vehicle drive motor torque based on the gradient and the load state includes:
[0026] Based on the slope, determine the initial value of the target output slope;
[0027] Based on the load state, the initial value of the target output slope is corrected to obtain the target output slope.
[0028] In one possible implementation, the step of outputting a motor torque command to the vehicle's motor controller based on the target output slope and the accelerator pedal opening includes:
[0029] The target speed of the vehicle is determined based on the opening of the accelerator pedal;
[0030] Determine the target motor torque based on the target speed of the vehicle;
[0031] Based on the target output slope and the target motor torque, the motor torque command is output to the motor controller.
[0032] In one possible implementation, the vehicle speed control method further includes:
[0033] Obtain the current opening of the accelerator pedal;
[0034] When the current opening of the accelerator pedal decreases compared to the previously acquired opening, a regenerative braking method using a motor is employed to control the vehicle to decelerate.
[0035] In one possible implementation, the method of using regenerative braking to control the vehicle deceleration includes:
[0036] Based on a preset deceleration rate, the vehicle is controlled to decelerate using the regenerative braking method of the motor.
[0037] Secondly, the present invention provides a vehicle speed control system, comprising:
[0038] The data acquisition unit is used to obtain the vehicle's load status and the slope of the road surface.
[0039] The first processing unit is configured to determine the maximum permissible speed of the vehicle based on the load state, and associate the maximum permissible speed with the accelerator pedal of the vehicle.
[0040] The second processing unit is used to determine the target output slope of the motor torque of the vehicle driving motor based on the slope and the load state.
[0041] Wherein, the target output slope is the slope that causes the vehicle's speed to change according to a preset acceleration;
[0042] The control execution unit is used to output a motor torque command to the vehicle's motor controller based on the target output slope and the opening of the accelerator pedal.
[0043] Thirdly, the present invention also provides an electric vehicle, comprising: a vehicle body and the vehicle speed control system described in the second aspect of the present invention.
[0044] According to the vehicle speed control method and control system provided by the present invention, after acquiring the vehicle's load status and the slope of the road surface, on the one hand, the maximum permissible vehicle speed is first determined based on the vehicle's load status, and then the maximum permissible vehicle speed is associated with the vehicle's accelerator pedal. This allows the vehicle speed to be adjusted in real time according to the accelerator pedal opening, within the limit of the maximum permissible speed, thus achieving speed control based on the vehicle's load and stable speed control. This avoids the driver having to control the vehicle speed by pressing the accelerator and brake, reducing energy consumption during vehicle operation and increasing the vehicle's driving range. On the other hand, after determining the target output slope that causes the vehicle speed to change according to a preset acceleration based on the slope and load status, a motor torque command is output to the vehicle's motor controller according to the target output slope and the accelerator pedal opening. This ensures that the vehicle maintains a consistent acceleration under different load conditions and road slopes, thereby avoiding situations such as excessive acceleration when unloaded and insufficient acceleration when climbing hills under full load, improving the smoothness of vehicle driving, and thus enhancing the user experience. Attached Figure Description
[0045] Figure 1 The diagram shows a flowchart of a vehicle speed control method provided in an embodiment of the present invention.
[0046] Figure 2 The diagram shown is a system framework diagram of a vehicle using the speed control method provided in an embodiment of the present invention.
[0047] Figure 3 The image shows a vehicle speed control method provided in an embodiment of the present invention. Figure 2 The schematic diagram shows the system framework in operation.
[0048] Figure 4 The diagram shown is a structural block diagram of a vehicle speed control system provided in an embodiment of the present invention.
[0049] Figure 5 The diagram shown is a structural schematic of a server provided in an embodiment of the present invention. Detailed Implementation
[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0051] As mentioned earlier, for electric vehicles controlled by torque, the acceleration rate is solely determined by the slope of the output torque from the vehicle's motor controller. This control method results in slow acceleration when loaded and unable to climb hills when the torque output slope is too small, while excessively large torque output slope leads to excessive acceleration when lightly loaded or unloaded, resulting in a poor user experience. Furthermore, the inability to limit vehicle speed with throttle opening causes the speed to continuously rise to its maximum value even with a small throttle opening. At higher speeds, the vehicle cannot maintain a constant speed through throttle pedal adjustment, leading to frequent acceleration and deceleration and excessive energy consumption. To improve user experience, reduce vehicle energy consumption, and enhance driving safety, this invention provides a vehicle speed control method and system. The method determines the maximum permissible speed based on the vehicle's load status and uses throttle opening to limit the speed, thereby improving the stability of speed control and reducing vehicle energy consumption. Furthermore, by adjusting the torque output slope of the vehicle's drive motor according to the vehicle's load status and the road surface gradient, the method ensures that the vehicle maintains a consistent acceleration under different loads and road gradients, thus improving the smoothness of vehicle operation.
[0052] The vehicle speed control method and vehicle speed control system provided by this invention can be applied to electronic devices. These electronic devices can be controllers installed on the electric vehicle itself, or other controllers independent of the electric vehicle, or smart terminal devices such as laptops, personal computers, and tablets. Of course, in some cases, they can also be servers on the network side.
[0053] Based on the above, see Figure 1 , Figure 1 This is a flowchart of a vehicle speed control method provided in an embodiment of the present invention. The flowchart of the vehicle speed control method provided in this embodiment may include:
[0054] S100: Obtain the vehicle's load status and the gradient of the road surface.
[0055] For electric vehicles such as trailers and electric container trucks, repeated loading and unloading of goods during operation results in different load states. Generally, vehicle load states are categorized as fully loaded, partially loaded, and unloaded. Understandably, the weight of a vehicle varies significantly depending on its load state. During vehicle operation, especially at start-up, weight has a significant impact on speed. For example, when unloaded, the vehicle accelerates quickly due to its lower weight, making a launch start more likely. Conversely, when fully loaded, the vehicle accelerates slowly due to its greater weight, leading to slow acceleration on inclines and a lack of power.
[0056] Furthermore, the slope of the road surface also has a significant impact on vehicle driving. For example, when driving uphill, a vehicle needs to overcome the driving resistance caused by the slope; while when driving downhill, a vehicle needs to avoid excessive speed.
[0057] Based on this, the embodiments of this application first obtain the vehicle's load status and the slope of the road surface, and then control the vehicle's speed according to the vehicle's load status and the slope of the road surface.
[0058] In some possible embodiments, the vehicle's load status can be detected by placing a weight sensor on the vehicle to detect the vehicle's load weight. The slope of the road surface the vehicle is traveling on can be detected by placing an inclinometer on the vehicle.
[0059] However, it's understandable that not all vehicles can have their load weight detected by installing weight sensors, such as tractor units and trailers. For example, a trailer is a mobile piece of equipment, and it's impossible to install weight sensors on all trailers.
[0060] To obtain the load status of a vehicle where the load weight cannot be detected by deploying weight sensors, a correspondence between different load statuses and preset torque ranges can be pre-set. Then, when the vehicle starts, after the speed of the drive motor changes from 0 to a preset target speed, the motor torque corresponding to that target speed is obtained as the target motor torque. Then, combined with the slope of the road surface, after determining the motor torque actually used for vehicle start-up after removing the influence of the slope, the preset torque range in which the motor torque actually used for vehicle start-up falls is determined, so as to realize the determination of the vehicle's load status.
[0061] Based on this, as an optional implementation, this embodiment provides multiple preset torque ranges and further provides a first preset mapping relationship, which records the correspondence between each preset torque range and different load states. Thus, after obtaining the vehicle's tilt angle and target motor torque (i.e., obtaining the slope of the road surface and the corresponding motor torque when the drive motor speed changes from 0 to a preset speed during vehicle startup), the actual motor torque used for vehicle startup is determined based on the slope and target motor torque. Then, based on the correspondence between the preset torque range into which the actual motor torque falls and the load state, the vehicle's load state is determined. Therefore, by obtaining the slope of the road surface and the initial output torque of the drive motor during startup, the vehicle's load state can be determined.
[0062] Furthermore, as an optional implementation, this embodiment provides a method for determining the actual motor torque for vehicle starting based on the slope and the target motor torque, including:
[0063] First, based on the slope and target motor torque Determine the slope resistance when starting the vehicle. :
[0064] (1)
[0065] in, This is the coefficient of friction, for example, a value of 0.2.
[0066] Then calculate the target motor torque. With the slope resistance The difference between the values yields the actual motor torque used for vehicle starting. :
[0067] (2)
[0068] Taking an electric container truck as an example, the preset speed of the drive motor can be set to 5 rpm. Assuming the vehicle's loading status is divided into three types—empty, half-loaded, and fully loaded—the preset torque range includes: less than... Greater than Greater than ;in, and These are the preset starting torques for vehicle no-load and half-load conditions, respectively. This allows for the establishment of a first preset mapping relationship between the preset torque range and different load states, as shown in Table 1.
[0069] Table 1
[0070]
[0071] Furthermore, based on the control requirements of actual applications, the load status can be further subdivided into no load, 25% load, half load (50% load), 75% load, 90% load, and full load (100% load). Correspondingly, the preset torque range is also set to correspond to the preset load status, thereby enabling more precise control of the vehicle speed.
[0072] It should be noted that the aforementioned preset torque range and the first preset mapping relationship between different load states are merely exemplary descriptions made to facilitate the understanding of the technical solution of this embodiment. Therefore, other preset torque ranges and preset mapping relationships between load states that are not mentioned are also within the protection scope of this invention.
[0073] S110. Determine the maximum permissible speed of the vehicle based on the load condition, and associate the maximum permissible speed with the vehicle's accelerator pedal.
[0074] Under different load conditions, the impact on vehicle operation varies. By determining the maximum permissible speed of the vehicle based on the load condition, it is possible to limit the maximum speed of the vehicle according to the vehicle load, thereby achieving safety protection when the vehicle is loaded and driving speed requirements when it is unloaded.
[0075] Furthermore, the determination of the maximum permissible speed of a vehicle can also take into account the slope of the road surface. For example, when a vehicle is traveling downhill, after determining the maximum permissible speed based on the vehicle's load status, the determined maximum permissible speed can be appropriately reduced based on the slope of the road surface. Conversely, when a vehicle is traveling uphill, the maximum permissible speed determined based on the vehicle's load status can be appropriately increased based on the slope of the road surface. This allows for the correction of the maximum permissible speed based on the road slope, thereby further improving the accuracy of vehicle speed control and enhancing the user experience.
[0076] Furthermore, by associating the maximum permissible speed determined based on the vehicle's load status with the accelerator pedal, the controller can limit the vehicle's maximum speed in real time based on the accelerator pedal opening percentage. This allows the vehicle speed to vary between 0 and the maximum permissible speed based on the accelerator pedal opening percentage, thereby achieving stable control of the vehicle speed without requiring the driver to control the speed by pressing the accelerator and brake pedals. This reduces energy consumption during vehicle operation and increases the vehicle's driving range.
[0077] In order to determine the maximum permissible speed of a vehicle based on its load status, the correspondence between different load statuses and the maximum permissible speed can be preset. Then, after determining the load status of the vehicle, the maximum permissible speed suitable for the vehicle can be determined based on the correspondence between the load status and the maximum permissible speed.
[0078] Based on this, as an optional implementation, this embodiment provides a second preset mapping relationship, which records the correspondence between each maximum permissible vehicle speed and different load states. Thus, after determining the load state, the maximum permissible vehicle speed can be conveniently determined through the second preset mapping relationship.
[0079] S120. Determine the target output slope of the motor torque of the vehicle's driving motor based on the gradient and load conditions.
[0080] In a vehicle controlled by torque, the acceleration rate is controlled by the slope of the output torque. Understandably, when the slope of the output torque is too small, the vehicle will accelerate too slowly when loaded, and may even be unable to climb hills or roll back when encountering slopes. On the other hand, when the slope of the output torque is too large, the vehicle will accelerate too quickly when lightly loaded or unloaded, resulting in a poor user experience.
[0081] Based on this, the embodiments of this application determine the target output slope for vehicle driving according to the slope of the road surface and the load state, so that the vehicle speed can change according to the preset acceleration slope, thereby ensuring that the vehicle maintains a consistent acceleration when driving under different load states and different road slopes, thereby preventing excessive acceleration when unloaded, which would lead to launch start, and excessive acceleration when fully loaded or climbing hills, resulting in weak acceleration, thus making the vehicle drive more smoothly.
[0082] As an optional implementation method, this embodiment first determines the slope. Determine the target output slope initial value :
[0083] (3)
[0084] Then, based on the load condition, determine the initial value of the target output slope. Make corrections.
[0085] In one possible embodiment, through actual testing and debugging, a correction coefficient corresponding to different load states is set to the initial value of the target output slope. Adjustments are made, with correction factors of 1, 1.3, and 1.6 corresponding to no-load, half-load, and full-load conditions, respectively. Therefore, when the vehicle is fully loaded: When the vehicle is half-loaded: However, when the vehicle is unloaded: .
[0086] S130: Based on the target output slope and the accelerator pedal opening, output motor torque command to the vehicle's motor controller.
[0087] When the accelerator pedal opening changes, it means the vehicle's speed needs to change. For vehicles using torque control, the acceleration rate is controlled by the slope of the torque output from the drive motor. Therefore, based on the accelerator pedal opening and the target output slope, the rate of acceleration and deceleration of the vehicle can be determined.
[0088] Based on this, as an optional implementation, this embodiment provides a specific method for outputting motor torque commands to the vehicle's motor controller according to the target output slope and the accelerator pedal opening, namely:
[0089] First, the target speed of the vehicle is determined based on the accelerator pedal opening. This is achieved by combining the percentage of accelerator pedal opening with the maximum permissible speed for the vehicle to determine the target speed at the current accelerator pedal opening. Then, after determining the target speed, the target motor torque corresponding to that speed is determined based on the relationship between vehicle speed and motor torque. Since the target output slope of the drive motor is already determined, a motor torque command is generated based on the target output slope and the target motor torque and output to the motor controller. The motor controller then controls the drive motor to gradually adjust its torque according to the target output slope until the target motor torque is reached.
[0090] In summary, through experimental verification, the vehicle speed control method provided in this embodiment limits the maximum permissible speed of the vehicle based on the vehicle's load status, and controls the output torque of the vehicle's drive motor to change according to a preset acceleration based on the load status and the slope of the road surface. Thus, by using a closed-loop speed control method, the vehicle speed accuracy is within ±1km, achieving the maximum speed limit of the vehicle under different loads, and maintaining a consistent acceleration control when the vehicle is under different loads and slopes.
[0091] Furthermore, this method can determine the vehicle's load state by measuring the slope of the road surface and the initial motor torque when the vehicle starts, making it applicable to various vehicles and thus having a wider range of applications.
[0092] Optionally, this method can be specifically based on, for example, Figure 2 The vehicle system framework shown is applied in vehicles, and its application principle is as follows: Figure 3 As shown, specifically: when the vehicle starts, the vehicle controller collects the vehicle tilt angle and the initial torque output by the drive motor through the tilt sensor and the electronic throttle pedal, respectively. After processing, the slope and load status of the driving road surface are obtained. Then, the maximum allowable speed of the vehicle is determined and associated with the electronic throttle pedal, and the target output slope of the motor torque is determined. Finally, the analog signal input from the electronic throttle pedal is sent to the vehicle controller. The vehicle controller converts the voltage input from the electronic throttle into a throttle opening percentage. The vehicle controller outputs the corresponding motor torque to the motor controller based on the throttle opening percentage and the target output slope, controlling the drive motor to rotate and drive the vehicle.
[0093] Furthermore, as an optional implementation, this embodiment also provides a vehicle speed control method for vehicle deceleration and braking, namely: after obtaining the current opening degree of the accelerator pedal, the current opening degree is compared with the previously obtained opening degree, and when the current opening degree of the accelerator pedal is smaller than the previously obtained accelerator pedal opening degree, a motor regenerative braking method is used to control the vehicle to decelerate, so that when the accelerator pedal is released while the vehicle is moving, braking energy is recovered through coasting braking to improve the vehicle's driving range.
[0094] To further improve the smoothness of vehicle braking, as an optional implementation, this embodiment also sets a preset deceleration to ensure that the vehicle decelerates at a uniform speed when using regenerative braking to control vehicle deceleration.
[0095] The vehicle speed control system provided in the embodiments of the present invention will be described below. The vehicle speed control system described below can be considered as a module architecture for implementing the vehicle speed control method and vehicle speed control system provided in the embodiments of the present invention; the description below can be referred to in conjunction with the above.
[0096] Optional, see Figure 4 , Figure 4 This is a structural block diagram of a vehicle speed control system provided in an embodiment of the present invention. The system may include:
[0097] The data acquisition unit 40 is used to acquire the vehicle's load status and the slope of the road surface.
[0098] The first processing unit 50 is used to determine the maximum permissible speed of the vehicle based on the load status and associate the maximum permissible speed with the accelerator pedal of the vehicle.
[0099] The second processing unit 60 is used to determine the target output slope of the motor torque of the vehicle driving motor based on the slope and load conditions.
[0100] The target output slope is the slope that causes the vehicle's speed to change according to a preset acceleration.
[0101] The control execution unit 70 is used to output motor torque commands to the vehicle's motor controller based on the target output slope and the opening of the accelerator pedal.
[0102] Optionally, the acquisition unit 40 is specifically used for: acquiring the vehicle tilt angle and target motor torque; wherein, the target motor torque is the motor torque corresponding to the change of the driving motor speed from 0 to a preset speed when the vehicle starts; determining the slope of the driving road surface based on the vehicle tilt angle; determining the actual motor torque used for vehicle starting based on the slope and the target motor torque; determining the target torque range to which the actual motor torque belongs among multiple preset torque ranges; and determining the load state corresponding to the target torque range based on a first preset mapping relationship; wherein, the first preset mapping relationship records the correspondence between each preset torque range and different load states.
[0103] Optionally, the acquisition unit 40 is more specifically used to: determine the slope resistance when the vehicle starts based on the slope and the target motor torque; calculate the difference between the target motor torque and the slope resistance to obtain the actual motor torque used for vehicle starting.
[0104] Optionally, the first processing unit 50 is specifically used to: determine the maximum permissible vehicle speed corresponding to the load state of the vehicle according to the second preset mapping relationship; wherein, the preset mapping relationship records the correspondence between each maximum permissible vehicle speed and different load states.
[0105] Optionally, the second processing unit 60 is specifically used to: determine the initial value of the target output slope based on the gradient; and correct the initial value of the target output slope based on the load status to obtain the target output slope.
[0106] Optionally, the control execution unit 70 is specifically used to: determine the target speed of the vehicle based on the opening of the accelerator pedal; determine the target motor torque based on the target speed of the vehicle; and output a motor torque command to the motor controller based on the target output slope and the target motor torque.
[0107] Optionally, the control execution unit 70 is also specifically used to: obtain the current opening of the accelerator pedal; and when the current opening of the accelerator pedal decreases compared to the previously obtained opening of the accelerator pedal, use a motor regenerative braking method to control the vehicle to decelerate.
[0108] Optionally, the control execution unit 70 is more specifically used to: control the vehicle to decelerate by using a motor regenerative braking method according to a preset deceleration.
[0109] Optionally, embodiments of the present invention also provide an electric vehicle, including: a vehicle body and a vehicle speed control system provided in any of the foregoing embodiments.
[0110] Below, for reference Figure 5 The server provided in this embodiment of the application can be described as follows: at least one processor 100, at least one communication interface 200, at least one memory 300 and at least one communication bus 400.
[0111] In this embodiment of the invention, the number of processor 100, communication interface 200, memory 300, and communication bus 400 is at least one, and the processor 100, communication interface 200, and memory 300 communicate with each other through communication bus 400; obviously, Figure 5 The communication connections shown for the processor 100, communication interface 200, memory 300, and communication bus 400 are optional.
[0112] Optionally, the communication interface 200 can be an interface of a communication module, such as the interface of a GSM module; the processor 100 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.
[0113] The memory 300 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.
[0114] Specifically, the processor 100 is used to execute the application program in the memory to implement the steps of the above-mentioned vehicle speed control method and vehicle speed control system.
[0115] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.
[0116] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.
[0117] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.
[0118] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.
[0119] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.
[0120] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.
Claims
1. A vehicle speed control method, characterized in that, include: Obtain the vehicle's load status and the gradient of the road surface; The maximum permissible speed of the vehicle is determined based on the load status, and the maximum permissible speed is associated with the accelerator pedal of the vehicle. Based on the slope and the load condition, determine the target output slope of the motor torque of the vehicle's drive motor; Wherein, the target output slope is the slope that causes the vehicle's speed to change according to a preset acceleration; Based on the target output slope and the accelerator pedal opening, a motor torque command is output to the vehicle's motor controller; The acquisition of the vehicle's load status and the slope of the road surface includes: Obtain the vehicle tilt angle and target motor torque of the vehicle; Wherein, the target motor torque is the motor torque corresponding to the change of the driving motor speed from 0 to the preset speed when the vehicle is started; The slope of the road surface is determined based on the vehicle tilt angle. Based on the slope and the target motor torque, determine the actual motor torque used for starting the vehicle; Among multiple preset torque ranges, determine the target torque range to which the actual motor torque belongs; Based on the first preset mapping relationship, the load state corresponding to the target torque range is determined; The first preset mapping relationship records the correspondence between each preset torque range and different load states; The step of determining the actual motor torque for starting the vehicle based on the slope and the target motor torque includes: The slope resistance during vehicle startup is determined based on the slope and the target motor torque. The difference between the target motor torque and the slope resistance is calculated to obtain the actual motor torque used for starting the vehicle.
2. The method according to claim 1, characterized in that, Determining the maximum permissible speed of the vehicle based on the load status includes: Based on the second preset mapping relationship, the maximum permissible vehicle speed corresponding to the load state of the vehicle is determined; The second preset mapping relationship records the correspondence between the maximum allowable vehicle speed and different load states.
3. The method according to claim 1, characterized in that, Determining the target output slope of the vehicle's drive motor torque based on the gradient and the load state includes: Based on the slope, determine the initial value of the target output slope; Based on the load state, the initial value of the target output slope is corrected to obtain the target output slope.
4. The method according to claim 1, characterized in that, The step of outputting a motor torque command to the vehicle's motor controller based on the target output slope and the accelerator pedal opening includes: The target speed of the vehicle is determined based on the opening of the accelerator pedal; Determine the target motor torque based on the target speed of the vehicle; Based on the target output slope and the target motor torque, the motor torque command is output to the motor controller.
5. The method according to claim 1, characterized in that, Also includes: Obtain the current opening of the accelerator pedal; When the current opening of the accelerator pedal decreases compared to the previously acquired opening, a regenerative braking method using a motor is employed to control the vehicle to decelerate.
6. The method according to claim 5, characterized in that, The method of using regenerative braking to control the vehicle deceleration includes: Based on a preset deceleration rate, the vehicle is controlled to decelerate using the regenerative braking method of the motor.
7. A vehicle speed control system for implementing the vehicle speed control method according to any one of claims 1 to 6, characterized in that, include: The data acquisition unit is used to obtain the vehicle's load status and the slope of the road surface. The first processing unit is configured to determine the maximum permissible speed of the vehicle based on the load state, and associate the maximum permissible speed with the accelerator pedal of the vehicle. The second processing unit is used to determine the target output slope of the motor torque of the vehicle driving motor based on the slope and the load state. Wherein, the target output slope is the slope that causes the vehicle's speed to change according to a preset acceleration; The control execution unit is used to output a motor torque command to the vehicle's motor controller based on the target output slope and the opening of the accelerator pedal.
8. An electric vehicle, characterized in that, include: The vehicle body and the vehicle speed control system as described in claim 7.