Hill Descent Control Method and System

Abstract

The present invention provides a downhill speed control method and system. The method is used to perform downhill speed control on a vehicle when the vehicle is going uphill or downhill, and includes: when the execution conditions for downhill speed control are satisfied, receiving torque signals fed back from each wheel of the vehicle; determining whether the difference between the torques corresponding to the respective torque signals is less than or equal to a predetermined threshold; and controlling the torque output to each wheel according to the determination result so that the vehicle travels at a predetermined target speed. According to the downhill speed control method and system of embodiments of the present invention, the vehicle can directly output torque to each wheel by using an electric motor, and can more quickly and accurately feedback the wheel torque in real time, and enable the vehicle to maintain a low and constant speed on a steep slope. In addition, according to the downhill speed control method and system of embodiments of the present invention, there is no need to rely on the engine system, the ABS and the ESP systems, and thus downhill speed control can be performed with a simple structure.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and particularly to a hill descent control method and system. Background Art

[0002] The traditional HDC (Hill Descent Control) system is based on the engine system, ABS (Antilock Brake System), and vehicle ESP (Electronic Stability Program) system. If the slope is not very steep, only the engine needs to apply reverse torque to maintain a low speed. In addition, as the slope increases, the ABS system will use high-frequency braking to assist in keeping the vehicle moving at a low speed. Moreover, if the road surface is rough, the ESP system will output different torques to different wheels. Summary of the Invention

[0003] The existing HDC system has the following problems: relying on the engine system, ABS, and ESP systems, thus having a complex structure; and if the accelerator (acceleration) pedal or brake (braking) pedal is depressed, the system will immediately fail, and the system cannot be continuously and automatically triggered afterwards; etc.

[0004] In view of this, according to one aspect of the present invention, there is provided a hill descent control method for performing hill descent control on a vehicle when the vehicle is going uphill or downhill. The vehicle is a wheel hub motor-driven vehicle, and the hill descent control method includes: when the execution conditions for the hill descent control are met, receiving torque signals fed back from each wheel of the vehicle; determining whether the difference between each torque corresponding to each torque signal is less than or equal to a predetermined threshold; and controlling the torque output to each wheel according to the determination result so that the vehicle travels at a predetermined target speed.

[0005] For the above-mentioned hill descent control method, in a possible implementation manner, controlling the torque output to each wheel according to the determination result includes: when it is determined that the difference is less than or equal to the predetermined threshold, outputting the same torque to each wheel; and when it is determined that the difference is greater than the predetermined threshold, outputting different torques to each wheel to balance the torques of each wheel.

[0006] For the above-mentioned hill descent control method, in a possible implementation manner, controlling the torque output to each wheel according to the determination result includes: obtaining the current gear of the vehicle; and controlling the torque output to each wheel according to the determination result and the current gear.

[0007] For the above-mentioned hill descent control method, in a possible implementation, the torque output to each wheel is controlled according to the judgment result and the current gear, including: when it is judged that the difference is less than or equal to the predetermined threshold and the current gear is the first gear, the same first torque is output to each wheel; when it is judged that the difference is less than or equal to the predetermined threshold and the current gear is a second gear different from the first gear, the same second torque is output to each wheel; when it is judged that the difference is greater than the predetermined threshold and the current gear is the first gear, different third torques are output to each wheel; and when it is judged that the difference is greater than the predetermined threshold and the current gear is the second gear, different fourth torques are output to each wheel.

[0008] For the above-mentioned hill descent control method, in a possible implementation, the predetermined target speed is determined based on the slope of the steep slope on which the vehicle is traveling and the corresponding relationship between the slope and the target speed stored in advance.

[0009] For the above-mentioned hill descent control method, in a possible implementation, it further includes: during the hill descent control, judging whether the accelerator pedal or the brake pedal of the vehicle is depressed, and when it is judged that the accelerator pedal or the brake pedal is depressed, interrupting the hill descent control.

[0010] For the above-mentioned hill descent control method, in a possible implementation, the execution condition is satisfied when the following conditions are met: the slope of the steep slope on which the vehicle is traveling is greater than or equal to a predetermined slope; the vehicle speed of the vehicle is greater than or equal to a predetermined vehicle speed; the accelerator pedal of the vehicle is not depressed; and the brake pedal of the vehicle is not depressed.

[0011] According to another aspect of the present invention, there is provided a hill descent control system for performing hill descent control on a vehicle when the vehicle is going up and down a slope. The vehicle is a wheel hub motor-driven vehicle. The hill descent control system includes: a receiving unit configured to receive torque signals fed back from each wheel of the vehicle when the execution condition of the hill descent control is satisfied; a judging unit configured to judge whether the difference between the torques corresponding to the respective torque signals is less than or equal to a predetermined threshold; and a control unit configured to control the torque output to each wheel according to the judgment result so that the vehicle travels at a predetermined target speed.

[0012] For the above-mentioned hill descent control system, in a possible implementation, the control unit is configured to: output the same torque to each wheel when the determination unit determines that the difference is less than or equal to the predetermined threshold; and output different torques to each wheel when the determination unit determines that the difference is greater than the predetermined threshold to balance the torques of the wheels.

[0013] For the above-mentioned hill descent control system, in a possible implementation, the control unit includes: an acquisition module configured to acquire the current gear of the vehicle; and a control module configured to control the torque output to each wheel according to the determination result and the current gear.

[0014] For the above-mentioned hill descent control system, in a possible implementation, the control module is configured to: output the same first torque to each wheel when the determination unit determines that the difference is less than or equal to the predetermined threshold and the current gear is the first gear; output the same second torque to each wheel when the determination unit determines that the difference is less than or equal to the predetermined threshold and the current gear is a second gear different from the first gear; output different third torques to each wheel when the determination unit determines that the difference is greater than the predetermined threshold and the current gear is the first gear; and output different fourth torques to each wheel when the determination unit determines that the difference is greater than the predetermined threshold and the current gear is the second gear.

[0015] For the above-mentioned hill descent control system, in a possible implementation, the predetermined target speed is determined based on the slope of the steep hill on which the vehicle is traveling and the corresponding relationship between the slope and the target speed stored in advance.

[0016] For the above-mentioned hill descent control system, in a possible implementation, the determination unit is further configured to determine whether the accelerator pedal or the brake pedal of the vehicle is depressed during the hill descent control, wherein the control unit is configured to interrupt the hill descent control when the determination unit determines that the accelerator pedal or the brake pedal is depressed.

[0017] For the above-mentioned hill descent control system, in a possible implementation, the execution condition is satisfied when the following conditions are met: the slope of the steep hill on which the vehicle is traveling is greater than or equal to a predetermined slope; the vehicle speed is greater than or equal to a predetermined vehicle speed; the accelerator pedal of the vehicle is not depressed; and the brake pedal of the vehicle is not depressed.

[0018] Through the hill descent control method and system according to the embodiments of the present invention, when the execution conditions for hill descent control are met, the torque output by the motor to each wheel can be controlled according to the judgment result of the difference between the torques of the received wheels, thereby performing corresponding hill descent control. Thus, according to the hill descent control method and system of the embodiments of the present invention, the vehicle can directly output torque to each wheel by using the motor, and can feedback the wheel torque faster and more accurately in real time, and keep the vehicle running at a low and constant speed on a steep slope. In addition, according to the hill descent control method and system of the embodiments of the present invention, it is not necessary to rely on the engine system, ABS and ESP systems, so that hill descent control can be performed with a simple structure.

[0019] Other features and aspects of the present invention will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings included in the specification and constituting a part of the specification show exemplary embodiments, features and aspects of the present invention together with the specification, and are used to explain the principles of the present invention.

[0021] Figure 1 The flowchart showing the hill descent control method according to an embodiment of the present invention.

[0022] Figure 2 The flowchart showing the hill descent control method according to another embodiment of the present invention.

[0023] Figure 3 The flowchart showing the hill descent control method according to still another embodiment of the present invention.

[0024] Figure 4 The block diagram showing the structure of the hill descent control system according to an embodiment of the present invention.

[0025] Figure 5 The block diagram showing the structure of the hill descent control system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0026] Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0027] The special term "exemplary" here means "serving as an example, embodiment or illustrative". Any embodiment described here as "exemplary" does not have to be construed as superior or better than other embodiments.

[0028] In addition, to better illustrate the present invention, numerous specific details are given in the following detailed embodiments. Those skilled in the art should understand that the present invention can be implemented without some of these specific details. In some instances, methods, means, elements, and circuits well-known to those skilled in the art are not described in detail so as to highlight the gist of the present invention.

[0029] As described in the background art, existing HDC systems rely on engine systems, ABS, and ESP systems, and thus their structures are relatively complex. In addition, existing HDC systems will immediately fail when the accelerator (acceleration) pedal or brake (braking) pedal is depressed, and cannot be continuously and automatically triggered thereafter.

[0030] In view of this, the present invention provides a hill descent control method and system to solve at least one of the above problems existing in the prior art.

[0031] The following will specifically describe the hill descent control method and system of the embodiments of the present invention. It should be noted that in the following description, the hill descent control method and system of the present invention are described in detail by taking the application of the hill descent control method and system of the present invention to in-wheel drive (IWD) vehicles as an example, but the present invention is not limited thereto, and the hill descent control method and system of the present invention are equally applicable to ordinary new energy vehicles (electric vehicles).

[0032] Figure 1 The flowchart showing the hill descent control method according to an embodiment of the present invention is shown. This hill descent control method is used to perform hill descent control on a vehicle when going up and down a slope. As Figure 1 shown, this hill descent control method mainly may include the following steps:

[0033] Step S100, when the execution conditions for hill descent control are met, receive torque signals fed back from each wheel of the vehicle;

[0034] Step S101, determine whether the difference between each torque corresponding to each torque signal is less than or equal to a predetermined threshold; and

[0035] Step S102, control the torque output to each wheel according to the determination result so that the vehicle travels at a predetermined target speed.

[0036] The following will specifically elaborate on each step.

[0037] For the above step S101, during the vehicle driving, it is necessary to determine whether the vehicle meets the execution conditions for hill descent control. This determination can be made by the HDC system or by an in-vehicle controller (e.g., HCU (Hybrid Control Unit)) installed on the vehicle. Hereinafter, the case where the HDC system makes this determination will be taken as an example for detailed description. However, those skilled in the art can understand that the following description is equally applicable to the case where the in-vehicle controller is used to make this determination.

[0038] In a possible implementation, it is determined that the execution conditions for hill descent control are met when the following conditions 1-4 are satisfied: the slope of the steep slope on which the vehicle is driving is greater than or equal to a predetermined slope (Condition 1); the vehicle speed is greater than or equal to a predetermined vehicle speed (Condition 2); the accelerator pedal of the vehicle is not depressed (Condition 3); and the brake pedal of the vehicle is not depressed (Condition 4). In other words, the HDC system needs to judge the above conditions 1-4 one by one, and determines that the execution conditions for hill descent control are met when the above conditions 1-4 are all satisfied.

[0039] The judgments of conditions 1-4 will be described separately below.

[0040] First, a slope sensor (or inclinometer) installed on the vehicle is used to measure the slope of the road surface on which the vehicle is driving in real time, and the measured slope is sent to the HDC system. The HDC system receives this slope (signal) and determines whether the slope is greater than or equal to a predetermined slope (e.g., 10°). If it is determined that the slope is greater than or equal to the predetermined slope, it is determined that Condition 1 is met, and then other judgments are carried out. On the other hand, if it is determined that the slope is less than the predetermined slope, the HDC system determines that Condition 1 is not met, so the hill descent control will not be activated. It should be noted that if the vehicle is going downhill, the measured slope is negative, and if the vehicle is going uphill, the measured slope is positive. Therefore, here it is necessary to compare the absolute value of the slope with the predetermined slope.

[0041] Next, a vehicle speed sensor installed on the vehicle is used to measure the driving speed (vehicle speed) of the vehicle, and the measured vehicle speed is sent to the HDC system. The HDC system receives this vehicle speed (signal) and determines whether the vehicle speed is greater than or equal to a predetermined vehicle speed (e.g., 8 km / h). If it is determined that the vehicle speed is greater than or equal to the predetermined vehicle speed, it is determined that Condition 2 is met, and then other judgments are carried out. On the other hand, if it is determined that the vehicle speed is less than the predetermined vehicle speed, it indicates that Condition 2 is not met, so the hill descent control will not be activated.

[0042] Next, the in-vehicle controller determines whether the accelerator pedal of the vehicle is depressed (whether the accelerator pedal signal is 0), and sends the determination result to the HDC system. The HDC system receives this determination result. If the accelerator pedal is not depressed (the accelerator pedal signal is 0), it is determined that Condition 3 is satisfied, and other determinations are then performed. On the other hand, if the accelerator pedal is depressed (the accelerator pedal signal is not 0), it is determined that Condition 3 is not satisfied, so the hill descent control is not started (if the hill descent control is being executed, the hill descent control is interrupted).

[0043] Next, the in-vehicle controller determines whether the brake pedal of the vehicle is depressed (whether the brake pedal signal is 0), and sends the determination result to the HDC system. The HDC system receives this determination result. If the brake pedal is not depressed (the brake pedal signal is 0), it is determined that Condition 4 is satisfied, and other determinations are then performed. On the other hand, if the brake pedal is depressed (the brake pedal signal is 1), it is determined that Condition 4 is not satisfied, so the hill descent control is not started (if the hill descent control is being executed, the hill descent control is interrupted).

[0044] When it is determined that all of the above Conditions 1-4 are satisfied, the HDC system determines that the execution condition of the hill descent control is satisfied, and thus the hill descent control described below can be executed.

[0045] It should be noted that the order of performing the determinations of the above Conditions 1-4 is not limited to that described above, and the determinations of the above Conditions 1-4 can be performed in any order. For example, the determinations of the above Conditions 1-4 can be performed in parallel. In addition, the execution conditions of the hill descent control are not limited to the above Conditions 1-4, and conditions can be added or reduced according to specific application scenarios.

[0046] When it is determined that the execution condition of the hill descent control is satisfied, in step S100, the HDC system receives the torque signals fed back from the respective wheels of the vehicle.

[0047] Specifically, the vehicle in the embodiment of the present invention is, for example, an IWD vehicle. In an IWD vehicle, an IWD motor is installed for each wheel. Thus, the torque signals of the respective wheels can be fed back to, for example, the in-vehicle controller of the vehicle by the IWD motors installed for the respective wheels. After the in-vehicle controller receives the torque signals of the respective wheels fed back by the IWD motors, these torque signals are sent to the HDC system.

[0048] Thus, the HDC system can receive the torque signals of the respective wheels fed back by the IWD motors during the execution of the hill descent control, and thus can know the torque of each wheel.

[0049] Next, in step S101, the HDC system compares the torques with each other to determine whether the difference between these torques is less than or equal to a predetermined threshold value.

[0050] Specifically, for example, a vehicle has four wheels, namely the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel. The torques corresponding to these four wheels are respectively represented as TrqFL, TrqFR, TrqRL, and TrqRR. Then, these four torques TrqFL, TrqFR, TrqRL, and TrqRR are compared with each other to determine whether the difference between these torques is less than or equal to a predetermined threshold value. This predetermined threshold value can usually be set by the system and represents the degree of difference in torque that can be tolerated between the wheels. Generally, if the vehicle is traveling on a flat road surface, these four torques TrqFL, TrqFR, TrqRL, and TrqRR are close to the same, and at this time, the difference between these torques is usually less than or equal to the predetermined threshold value. In the ideal state where the road surface is absolutely flat, it is possible that TrqFL = TrqFR = TrqRL = TrqRR, that is, the difference between the torques is 0. On the other hand, if the vehicle is traveling on a bumpy road surface, these four torques TrqFL, TrqFR, TrqRL, and TrqRR are different from each other, and at this time, the difference between these torques may be greater than the predetermined threshold value.

[0051] Next, in step S102, the HDC system controls the torque output by the IWD motor to each wheel according to the determination result in step S101, so that the vehicle travels at a predetermined target speed (for example, 10 km / h), thereby performing the hill descent control. The detailed control in step S102 will be specifically described later.

[0052] In addition, during the execution of the hill descent control, if the accelerator pedal or the brake pedal of the vehicle is depressed (the accelerator pedal signal is not 0 or the brake pedal is 1), it indicates that the driver or the like attempts to control the driving of the vehicle. In this case, the HDC system can interrupt the hill descent control. However, if the HDC system then determines that the execution conditions for the hill descent control are met after interrupting the hill descent control, the hill descent control is automatically enabled again, and the above-described hill descent control process is executed.

[0053] Accordingly, the hill descent control method according to an embodiment of the present invention can, when the execution conditions for hill descent control are satisfied, control the torque output by the motor to each wheel based on the determination result of the difference between the torques of the received wheels, thereby performing corresponding hill descent control. Accordingly, when the vehicle is traveling on a steep slope, there is no need to step on the accelerator pedal and the brake pedal, and the HDC system or the vehicle-mounted controller can monitor the trigger conditions and control the motor (such as the IWD motor) to output torque so that the vehicle (such as an IWD vehicle) maintains a low and constant speed. In addition, according to the hill descent control method according to an embodiment of the present invention, the vehicle can directly output torque to each wheel by using the motor, and can provide real-time feedback of wheel torque faster and more accurately. In addition, according to the hill descent control method according to an embodiment of the present invention, there is no need to rely on the engine system, the ABS, and the ESP systems, and thus hill descent control can be performed with a simple structure. In addition, according to the hill descent control method according to an embodiment of the present invention, when the throttle (acceleration) pedal or the brake (deceleration) pedal is stepped on, the hill descent control is interrupted, and then the hill descent control can be continuously and automatically triggered when the execution conditions for hill descent control are satisfied.

[0054] The control process in step S102 will be specifically described below.

[0055] Figure 2 A flowchart showing a hill descent control method according to another embodiment of the present invention is shown. In Figure 2 this, the same steps as those in Figure 1 will be given the same reference numerals, and will not be described in detail here.

[0056] As Figure 2 shown, in step S100, as described above, when the execution conditions for hill descent control are satisfied, the HDC system receives torque signals fed back from the wheels of the vehicle.

[0057] In step S101, it is determined whether the difference between the torques corresponding to the torque signals is less than or equal to a predetermined threshold. When it is determined that the difference between the torques corresponding to the torque signals is less than or equal to the predetermined threshold, step S1021 can be executed. On the other hand, when it is determined that the difference between the torques corresponding to the torque signals is greater than the predetermined threshold, step S1022 can be executed.

[0058] In step S1021, since the difference between the torques is small, that is, within the tolerable difference range, the motor outputs the same torque to each wheel. In other words, the motor outputs the same torque for each wheel. For example, this occurs when the road surface of the steep slope is relatively flat.

[0059] On the other hand, in step S1022, since the difference between the torques is relatively large, that is, it exceeds the tolerable difference range, the motor outputs different torques to each wheel to balance the torques of each wheel. In other words, different torques are output to the motors for each wheel so that the torques of each wheel are the same or approximately the same. For example, this situation occurs when the road surface of a steep slope is uneven.

[0060] Thus, according to the steep slope descent control method of the embodiment of the present invention, different steep slope descent controls can be performed based on the difference between the torques of the respective wheels of the vehicle. That is, when the difference is less than or equal to a predetermined threshold, the same torque is output to each wheel, and when the difference is greater than the predetermined threshold, different torques are output to each wheel to balance the torques of each wheel. Thus, according to the steep slope descent control method of the embodiment of the present invention, the vehicle can directly output corresponding torques to each wheel by using the motor, and can feedback the wheel torque faster and more accurately in real time.

[0061] Figure 3 A flowchart showing a steep slope descent control method according to another embodiment of the present invention is shown. In Figure 2 In, the same steps as those in Figure 1 will be given the same reference numerals, and will not be described in detail here.

[0062] As Figure 3 shown, in step S100, as described above, when the execution condition of the steep slope descent control is satisfied, the HDC system receives the torque signals fed back from the respective wheels of the vehicle.

[0063] Next, in step S103, the current gear of the vehicle is acquired. For example, the in-vehicle controller of the vehicle can detect the current gear of the vehicle and notify the HDC system of the current gear. Thus, the HDC system can acquire the current gear of the vehicle. The gears of the vehicle include, for example, a first gear and a second gear. In a possible implementation, the first gear is a forward gear (e.g., D gear), and the second gear is a reverse gear (e.g., R gear). However, the present invention is not limited thereto, and the first gear and the second gear can be other gears.

[0064] Next, in step S101, as described above, it is determined whether the difference between the respective torques corresponding to the respective torque signals is less than or equal to a predetermined threshold. Among them, the order of step S103 and step S101 can be swapped, or step S103 and step S101 can be executed in parallel.

[0065] Next, the torque output to each wheel is controlled based on the current gear acquired in step S103 and the determination result in step S101. The details of this process will be described below.

[0066] AsFigure 3 As shown, when it is determined in step S101 that the difference between the torques corresponding to the respective torque signals is less than or equal to a predetermined threshold, step S1023 or step S1024 is executed. On the other hand, when it is determined in step S101 that the difference between the torques corresponding to the respective torque signals is greater than the predetermined threshold, step S1025 or step S1026 is executed.

[0067] In step S1023, if the current gear is the first gear, the HDC system controls the motor to output the same first torque to the corresponding wheels.

[0068] In step S1024, if the current gear is the second gear, the HDC system controls the motor to output the same second torque to the corresponding wheels.

[0069] In step S1025, if the current gear is the first gear, the HDC system controls the motor to output different third torques to the corresponding wheels.

[0070] In step S1026, if the current gear is the second gear, the HDC system controls the motor to output different fourth torques to the corresponding wheels.

[0071] Hereinafter, the case where the first gear is the forward gear and the second gear is the reverse gear will be taken as an example for explanation.

[0072] Specifically, if the difference between the torques of the respective wheels is less than or equal to the predetermined threshold and the current gear is the forward gear, then in step S1023, the HDC system controls the motor to output the same reverse torque to the corresponding wheels, so that the vehicle travels at a predetermined target speed.

[0073] If the difference between the torques of the respective wheels is less than or equal to the predetermined threshold and the current gear is the reverse gear, then in step S1024, the HDC system controls the motor to output the same forward torque to the corresponding wheels, so that the vehicle travels at a predetermined target speed.

[0074] If the difference between the torques of the respective wheels is greater than the predetermined threshold and the current gear is the forward gear, then in step S1025, the HDC system controls the motor to output different reverse torques to the corresponding wheels, so as to balance the torques of the respective wheels and make the vehicle travel at a predetermined target speed.

[0075] If the difference between the torques of the respective wheels is greater than the predetermined threshold and the current gear is the reverse gear, then in step S1026, the HDC system controls the motor to output different reverse torques to the corresponding wheels, so as to balance the torques of the respective wheels and make the vehicle travel at a predetermined target speed.

[0076] Thus, the hill descent control method according to the embodiments of the present invention can perform corresponding hill descent control according to the difference between the torques of each wheel and the current gear. Thus, with the hill descent control method according to the embodiments of the present invention, the vehicle can directly output corresponding torques to each wheel by using the motor, and can feedback the wheel torque in real time faster and more accurately.

[0077] In addition, during the hill descent control of the above embodiment, the vehicle is made to travel at a constant target speed. However, in a possible implementation, different predetermined target speeds can be determined according to the slope of the steep hill.

[0078] Specifically, the vehicle can include a memory for storing data, and in this memory, the corresponding relationship between the slope and the target speed can be pre-stored. Generally speaking, the steeper the slope, the slower the target speed. In this case, after the slope sensor detects the slope of the steep hill, the target speed at which the vehicle is to travel can be determined according to the detected slope and the pre-stored corresponding relationship between the slope and the target speed. After determining the target speed, the torque output to the wheels is controlled so that the vehicle travels through the steep hill at this target speed.

[0079] In addition, it should be noted that for the parameters such as the predetermined slope, the predetermined vehicle speed, the predetermined threshold, and the predetermined target speed mentioned in the above embodiments, they can be preset by the system or set by the user. In addition, the specific values of these parameters involved in the embodiments of the present invention are only examples, and the present invention is not limited thereto, and any reasonable values can be set according to the specific application scenarios.

[0080] Figure 4 The structural block diagram of a hill descent control system according to an embodiment of the present invention is shown. This hill descent control system is mainly used to perform hill descent control on the vehicle when the vehicle is going up or down a hill. As Figure 4 shown, the hill descent control system 40 mainly can include: a receiving unit 41, which is configured to receive torque signals fed back from each wheel of the vehicle when the execution conditions of the hill descent control are met; a judging unit 42, which is configured to judge whether the difference between the torques corresponding to the respective torque signals is less than or equal to a predetermined threshold; and a control unit 43, which is configured to control the torque output to the respective wheels according to the judgment result so that the vehicle travels at a predetermined target speed.

[0081] The hill descent control system 40 according to the embodiments of the present invention can execute the hill descent control method described in any of the above embodiments. For the details of the above hill descent control method, please refer to the specific description of the above embodiments, and will not be described in detail here.

[0082] Accordingly, the hill descent control system according to an embodiment of the present invention can, when the execution conditions of hill descent control are satisfied, control the torque output by the motor to each wheel based on the determination result of the difference between the torques of the received wheels, thereby performing corresponding hill descent control. Accordingly, when the vehicle is traveling on a steep slope, there is no need to step on the accelerator pedal and the brake pedal, and the HDC system or the vehicle-mounted controller can monitor the trigger conditions and control the motor (such as the IWD motor) to output torque so that the vehicle (such as an IWD vehicle) travels at a low and constant speed. In addition, in the hill descent control system according to an embodiment of the present invention, the vehicle can directly output torque to each wheel by using the motor, and can feedback the wheel torque faster and more accurately in real time. In addition, in the hill descent control system according to an embodiment of the present invention, there is no need to rely on the engine system, the ABS, and the ESP systems, and thus hill descent control can be performed with a simple structure.

[0083] Figure 5 The structural block diagram of a hill descent control system according to another embodiment of the present invention is shown. Figure 5 Same as that in Figure 4 the same components are given the same reference numerals, and their detailed descriptions will be omitted here.

[0084] As Figure 5 shown, the main difference between the hill descent control system 50 of this embodiment and the hill descent control system 40 of the above embodiment is that the control unit 43 may specifically include: an acquisition module 431 configured to acquire the current gear of the vehicle; and a control module 432 configured to control the torque output to each wheel based on the determination result and the current gear.

[0085] In addition, for the above hill descent control system 50, in a possible implementation manner, the control unit 43 may be configured to: output the same torque to each wheel when the determination unit 42 determines that the difference is less than or equal to the predetermined threshold; and output different torques to each wheel when the determination unit 42 determines that the difference is greater than the predetermined threshold to balance the torques of the wheels.

[0086] For the above-mentioned hill descent control system 50, in a possible implementation, the control module 432 may be configured to: when the determination unit 42 determines that the difference is less than or equal to the predetermined threshold and the current gear is the first gear, output the same first torque to each wheel; when the determination unit 42 determines that the difference is less than or equal to the predetermined threshold and the current gear is a second gear different from the first gear, output the same second torque to each wheel; when the determination unit 42 determines that the difference is greater than the predetermined threshold and the current gear is the first gear, output different third torques to each wheel; and when the determination unit 42 determines that the difference is greater than the predetermined threshold and the current gear is the second gear, output different fourth torques to each wheel.

[0087] For the above-mentioned hill descent control system 50, in a possible implementation, the predetermined target speed is determined based on the slope of the steep hill on which the vehicle is traveling and the corresponding relationship between the slope and the target speed stored in advance.

[0088] For the above-mentioned hill descent control system 50, in a possible implementation, the determination unit 42 is further configured to determine whether the accelerator pedal or the brake pedal of the vehicle is depressed during the hill descent control, wherein the control unit 43 is configured to interrupt the hill descent control when the determination unit determines that the accelerator pedal or the brake pedal is depressed.

[0089] For the above-mentioned hill descent control system 50, in a possible implementation, the execution condition is satisfied when the following conditions are met: the slope of the steep hill on which the vehicle is traveling is greater than or equal to a predetermined slope; the vehicle speed of the vehicle is greater than or equal to a predetermined vehicle speed; the accelerator pedal of the vehicle is not depressed; and the brake pedal of the vehicle is not depressed.

[0090] For the above-mentioned hill descent control system, in a possible implementation, the vehicle is a wheel hub motor driven vehicle, i.e., an IWD vehicle.

[0091] Accordingly, the hill descent control system according to an embodiment of the present invention can perform different hill descent controls based on the differences between the torques of the respective wheels of the vehicle. That is, when the difference is less than or equal to a predetermined threshold, the same torque is output to each wheel, and when the difference is greater than the predetermined threshold, different torques are output to each wheel to balance the torques of the respective wheels. Accordingly, with the hill descent control system according to an embodiment of the present invention, the vehicle can directly output corresponding torques to each wheel by using an electric motor, and can provide a faster and more accurate real-time feedback of the wheel torque. In addition, with the hill descent control system according to an embodiment of the present invention, it is possible to perform corresponding hill descent controls based on the differences between the torques of the respective wheels and the current gear position.

[0092] The embodiments of the present invention have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the technical improvements in the technology in the market, or to enable other ordinary skilled persons in the technical field to understand the embodiments disclosed herein.

Claims

1. A hill descent control method for performing hill descent control on a vehicle when the vehicle is going up or down a slope, the vehicle being a wheel hub motor-driven vehicle, characterized in that, The steep slope descent control method includes: Receiving torque signals fed back from the respective wheels of the vehicle when the execution conditions for the steep slope descent control are met; Judging whether the difference between the respective torques corresponding to the respective torque signals is less than or equal to a predetermined threshold; and Controlling the torque output to the respective wheels according to the judgment result so that the vehicle travels at a predetermined target speed, wherein controlling the torque output to the respective wheels according to the judgment result includes: Obtaining the current gear of the vehicle; Controlling the torque output to the respective wheels according to the judgment result and the current gear.

2. The downhill speed control method according to claim 1, characterized in that, Controlling the torque output to the respective wheels according to the judgment result includes: Outputting the same torque to the respective wheels when it is judged that the difference is less than or equal to the predetermined threshold; and Outputting different torques to the respective wheels when it is judged that the difference is greater than the predetermined threshold to balance the torques of the respective wheels.

3. The downhill speed control method according to claim 1, characterized in that It further includes: During the steep slope descent control, judging whether the accelerator pedal or the brake pedal of the vehicle is depressed, and Interrupting the steep slope descent control when it is judged that the accelerator pedal or the brake pedal is depressed.

4. The hill descent control method according to any one of claims 1 to 3, characterized in that, The execution conditions are met when the following conditions are satisfied: the slope of the steep slope on which the vehicle travels is greater than or equal to a predetermined slope; the vehicle speed is greater than or equal to a predetermined vehicle speed; the accelerator pedal of the vehicle is not depressed; and the brake pedal of the vehicle is not depressed.

5. A hill descent control system for performing hill descent control on a vehicle when the vehicle is going up or down a slope, where the vehicle is a wheel hub motor-driven vehicle, characterized in that, The steep slope descent control system includes: A receiving unit configured to receive torque signals fed back from the respective wheels of the vehicle when the execution conditions for the steep slope descent control are met; A judging unit configured to judge whether the difference between the respective torques corresponding to the respective torque signals is less than or equal to a predetermined threshold; and A control unit configured to control the torque output to the respective wheels according to the judgment result so that the vehicle travels at a predetermined target speed.

6. The hill descent control system according to claim 5, wherein, The control unit is configured to: Output the same torque to the respective wheels when the judging unit judges that the difference is less than or equal to the predetermined threshold; and Output different torques to the respective wheels when the judging unit judges that the difference is greater than the predetermined threshold to balance the torques of the respective wheels.

7. The hill descent control system according to claim 5, characterized in that The control unit includes: An obtaining module configured to obtain the current gear of the vehicle; A control module configured to control the torque output to the respective wheels according to the judgment result and the current gear.

8. The hill descent control system according to claim 5, wherein The judging unit is further configured to judge whether the accelerator pedal or the brake pedal of the vehicle is depressed during the steep slope descent control, wherein the control unit is configured to interrupt the steep slope descent control when the judging unit judges that the accelerator pedal or the brake pedal is depressed.

9. The hill descent control system according to any one of claims 5 to 8, characterized in that The execution conditions are met when the following conditions are satisfied: the slope of the steep slope on which the vehicle travels is greater than or equal to a predetermined slope; the vehicle speed is greater than or equal to a predetermined vehicle speed; the accelerator pedal of the vehicle is not depressed; and the brake pedal of the vehicle is not depressed.

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