Uphill assist control method and system based on motor control

Abstract

The present invention discloses a method and system for hill-start assist control based on motor control. The method comprises: determining whether the vehicle is in a rolling state, and if so, proceeding to the next step; calculating the current motor acceleration; searching, based on the current motor acceleration, the hill-holding torque corresponding to the current motor acceleration from a pre-defined hill-holding torque table; a motor controller implementing the hill-holding torque to suppress the vehicle from rolling; and after completing the loading of the hill-holding torque, the motor controller controls the motor to operate at zero speed via a proportional-integral controller to implement the vehicle's hill-start assist function. This invention eliminates the need for a slope sensor to achieve cost reduction while also preventing the driver from rolling during a hill start.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a hill-climbing assist control method and system based on motor control. Background Art

[0002] The statements in this section merely mention background art related to the present invention and do not necessarily constitute prior art.

[0003] Hill-start Assist Control (HAC) is a function developed based on the Electronic Stability Program (ESP). When starting on a slope, the vehicle can continue to brake for a few seconds even if the right foot is off the brake pedal. This allows the driver to easily transfer his foot from the brake pedal to the accelerator pedal to prevent the vehicle from slipping and causing an accident.

[0004] However, due to various factors, including vehicle cost, application, and vehicle model, many low-priced electric vehicles are still not equipped with ESP, or those that are equipped lack the hill-start assist function. This can easily cause the vehicle to roll away when starting on a slope, leading to traffic accidents. To address this issue, related technologies have added a slope sensor to obtain the slope value and implement the hill-start assist function by stalling the motor.

[0005] Faced with the current rise in raw material prices and the ever-increasing cost of car manufacturing, finding cost-reduction solutions has become a key task for OEMs. Summary of the Invention

[0006] In order to address the deficiencies of the prior art, the present invention provides a hill-climbing assist control method and system based on motor control; the slope sensor can be eliminated to achieve cost reduction needs, while preventing the driver from slipping during starting on a slope.

[0007] In a first aspect, the present invention provides a hill-climbing assist control method based on motor control;

[0008] A hill-climbing assist control method based on motor control, comprising:

[0009] Determine whether the vehicle is in a rolling state. If so, proceed to the next step.

[0010] Calculate the current motor acceleration;

[0011] Based on the current motor acceleration, the corresponding holding torque is found from a pre-defined holding torque table; the motor controller applies the holding torque to prevent the vehicle from rolling away.

[0012] After completing the loading of the hill-holding torque, the motor controller controls the motor to operate at zero speed through the proportional-integral controller to realize the vehicle's uphill assist function.

[0013] In a second aspect, the present invention provides a hill-climbing assist control system based on motor control;

[0014] A hill-climbing assist control system based on motor control, comprising:

[0015] A judgment module is configured to: judge whether the vehicle is in a rolling state, and if so, enter the calculation module;

[0016] A calculation module is configured to: calculate the current motor acceleration;

[0017] The table lookup module is configured to: look up the hill-holding torque corresponding to the current motor acceleration from a pre-defined hill-holding torque table according to the current motor acceleration; and the motor controller implements the loading of the hill-holding torque to prevent the vehicle from rolling;

[0018] The control module is configured as follows: after the motor controller completes the loading of the hill-holding torque, it controls the motor to operate at zero speed through the proportional-integral controller to realize the vehicle uphill assist function.

[0019] Compared with the existing technology, the beneficial effects of the present invention are: through the motor controller, the slope sensor can be eliminated, which meets the current cost reduction needs of the entire vehicle, while realizing the uphill assist function and solving the problem of the driver starting on a slope. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 Flowchart for determining the activation of the hill-climbing assist function;

[0022] Figure 2 Flowchart of the method for implementing the function. DETAILED DESCRIPTION

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0026] All data in this embodiment is obtained in compliance with laws and regulations and based on the consent of the user, and is used legally.

[0027] Example 1

[0028] This embodiment provides a hill-climbing assist control method based on motor control;

[0029] like Figure 2 As shown, a hill-climbing assist control method based on motor control includes:

[0030] S101: Determine whether the vehicle is in a rolling state. If yes, proceed to S102;

[0031] S102: Calculate the current motor acceleration;

[0032] S103: According to the current motor acceleration, the hill-holding torque corresponding to the current motor acceleration is searched from a pre-defined hill-holding torque table; the motor controller implements the hill-holding torque loading to prevent the vehicle from rolling;

[0033] S104: After the motor controller completes loading of the hill-holding torque, it controls the motor to operate at a zero speed condition through a proportional-integral controller to implement a vehicle uphill assist function.

[0034] Furthermore, if Figure 1 As shown, before the step S101: determining whether the vehicle is in a rolling state, the following steps are further included:

[0035] S100-1: Determine whether the vehicle is in the forward gear or the reverse gear. If yes, proceed to S100-2; if no, end;

[0036] S100-2: Determine whether the vehicle is in a parked state. If so, proceed to S101; if not, return to S100-1.

[0037] Furthermore, the S100-2: determining whether the vehicle is in a parked state; the specific process includes:

[0038] If the brake pedal remains depressed and the motor speed remains within a first set speed for a first set time, the vehicle is considered to be in a parked state.

[0039] Exemplarily, the first set rotation speed is, for example, within a range of ±5 rpm.

[0040] Exemplarily, the first set time is, for example, 0.5s-1s.

[0041] Furthermore, the step S101: determining whether the vehicle is in a rolling state specifically includes:

[0042] When the vehicle is in a forward gear, if the motor speed is less than the second set speed and lasts for a second set time, or if the motor speed is less than the third set speed, it is determined to be slipping; wherein the second set speed and the third set speed are both negative values ​​and the second set speed is greater than the third set speed.

[0043] Exemplarily, the second set rotation speed is, for example: -10 rpm.

[0044] Exemplarily, the second set time is, for example, 200ms-800ms.

[0045] Exemplarily, the third set rotation speed is, for example: -20 rpm.

[0046] Furthermore, the step S101 of determining whether the vehicle is in a rolling state further includes:

[0047] When the vehicle is in reverse gear, if the motor speed is greater than the fourth set speed for a third set time, or if the motor speed is greater than the fifth set speed, it is determined to be slipping; wherein the fourth set speed and the fifth set speed are both positive values ​​and the fourth set speed is less than the fifth set speed.

[0048] For example, the fourth set speed is, for example, 10 rpm.

[0049] For example, the third set time is, for example: 200ms-800ms

[0050] For example, the fifth set speed is, for example, 20 rpm.

[0051] It should be understood that the above-mentioned setting of the conditions for determining whether the vehicle is in a rolling state can avoid misjudgment of the vehicle creeping on a small slope.

[0052] Furthermore, the step S102: calculating the current motor acceleration refers to performing the calculation when the vehicle is in a forward gear or a reverse gear and the motor controller detects that the brake pedal is released and the accelerator pedal opening / closing degree is zero.

[0053] Furthermore, in step S103, based on the current motor acceleration, a hill-holding torque corresponding to the current motor acceleration is searched from a pre-defined hill-holding torque table; the motor controller implements loading of the hill-holding torque to suppress vehicle roll; wherein the hill-holding torque table is obtained through a previous calibration process; and the process of obtaining the hill-holding torque table includes:

[0054] When the vehicle is half-loaded, calculate the acceleration of the vehicle when the brake pedal is released on different slopes. At the same time, record the holding torque required to keep the vehicle stationary (or at zero speed) on the slope. Compile the holding torques corresponding to different accelerations into a table. The acceleration and holding torque in the table are in a one-to-one correspondence.

[0055] Exemplarily, the step S103: based on the current motor acceleration, the hill-holding torque corresponding to the current motor acceleration is searched from a pre-established hill-holding torque table; the motor controller implements the loading of the hill-holding torque to suppress the vehicle from rolling away; the hill-holding torque obtained from the table lookup is output as the torque loop, and after the motor controller starts the uphill assist function, it is loaded into the hill-holding torque to suppress the vehicle from rolling away.

[0056] Furthermore, the step S104: after the motor controller completes loading of the hill-holding torque, controls the motor to operate at a zero speed condition through a proportional-integral controller to implement a vehicle uphill assist function; specifically includes:

[0057] The proportional integral controller PI (proportional integral controller) is used to adjust and control the motor to operate at zero speed.

[0058] The target speed is 0 rpm. The difference between the current motor speed and the target speed is used as the input of the PI controller. Through proportional-integral adjustment, the output is the motor torque.

[0059] The PI parameters are segmented according to the speed difference. When the speed difference is greater than 40 rpm, a larger set of parameters is used, such as p is 0.1 and I is 0.01; when the speed difference is less than 40 rpm, a smaller set of parameters is used, such as p is 0.025 and I is 0.025.

[0060] This method, implemented through a motor controller, eliminates the need for a slope sensor and achieves cost reduction. Furthermore, through preliminary calibration, this method estimates the required holding torque under different rolling accelerations. Using a torque loop rapid loading method, the motor torque output is controlled to maintain a constant value near the holding torque. Finally, fine-tuning the speed loop enables hill-start assist, resolving the driver's hill-starting challenge.

[0061] The above method includes preliminary calibration work, function determination work and function realization work;

[0062] During the initial calibration, the vehicle is half-loaded and the acceleration of the vehicle rolling when the brake pedal is released is calculated on different slopes. The holding torque required to maintain vehicle stability on the slope is also recorded. The corresponding holding torques under different accelerations are tabulated for software lookup.

[0063] Function determination work: the motor controller detects whether the vehicle's uphill assist function is turned on and whether there is a slipping phenomenon. If the conditions are met, the uphill assist function is activated to assist the driver to start on a slope;

[0064] To achieve this function, the motor controller looks up the table according to the acceleration of the vehicle's slipping, and obtains the currently required hill-holding torque. The motor controller first works in the torque loop to quickly load the hill-holding torque and suppress the vehicle's backward slipping tendency. After completing the loading of the hill-holding torque, the proportional-integral controller uses PI adjustment to perform precise control, controlling the motor to operate at zero speed, thereby realizing the vehicle's uphill assist function.

[0065] Example 2

[0066] This embodiment provides a hill-climbing assist control system based on motor control;

[0067] A hill-climbing assist control system based on motor control, comprising:

[0068] A judgment module is configured to: judge whether the vehicle is in a rolling state, and if so, enter the calculation module;

[0069] A calculation module is configured to: calculate the current motor acceleration;

[0070] The table lookup module is configured to: look up the hill-holding torque corresponding to the current motor acceleration from a pre-defined hill-holding torque table according to the current motor acceleration; and the motor controller implements the loading of the hill-holding torque to prevent the vehicle from rolling;

[0071] The control module is configured as follows: after the motor controller completes the loading of the hill-holding torque, it controls the motor to operate at zero speed through the proportional-integral controller to realize the vehicle uphill assist function.

[0072] It should be noted that the above-mentioned determination module, calculation module, table lookup module, and control module correspond to steps S101 to S104 in Example 1. The examples and application scenarios implemented by the above-mentioned modules and the corresponding steps are the same, but are not limited to the contents disclosed in Example 1. It should be noted that the above-mentioned modules, as part of the system, can be executed in a computer system, such as a set of computer-executable instructions.

[0073] The descriptions of the various embodiments in the above embodiments have different focuses. For parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0074] The proposed system can be implemented in other ways. For example, the system embodiment described above is merely illustrative. For example, the above module division is only a logical function division. In actual implementation, other division methods may be used. For example, multiple modules can be combined or integrated into another system, or some features can be ignored or not implemented.

[0075] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for uphill assist control based on motor control, characterized in that: include: Determine whether the vehicle is in a rolling state. If so, proceed to the next step. Calculate the current motor acceleration; Based on the current motor acceleration, the corresponding holding torque is found from a pre-defined holding torque table; the motor controller applies the holding torque to prevent the vehicle from rolling away. The hill-holding torque table is obtained through preliminary calibration work; the acquisition process of the hill-holding torque table includes: When the vehicle is half-loaded and the brake pedal is released, the acceleration of the vehicle rolling away is calculated on different slopes. The holding torque required to maintain the vehicle stationary on the slope is also recorded. The corresponding holding torques at different accelerations are tabulated. The accelerations and holding torques in the table are in a one-to-one correspondence. The holding torque obtained from the table is used as the torque loop output. After the motor controller starts the uphill assist function, it is loaded into the holding torque to suppress the vehicle's tendency to roll. After the motor controller completes the loading of the hill-holding torque, it controls the motor to operate at zero speed through the proportional-integral controller to achieve the vehicle's uphill assist function; Determine whether the vehicle is in a rolling state, which also includes: (1) Determine whether the vehicle is in forward gear or reverse gear. If yes, proceed to (2); if not, end; (2) Determine whether the vehicle is in a parked state. If so, determine whether the vehicle is in a rolling state. If not, return to (1). Determine whether the vehicle is in a parked state; the specific process includes: If the brake pedal remains depressed and the motor speed remains within a first set speed for a first set time, the vehicle is considered to be in a parked state.

2. The uphill assist control method based on motor control according to claim 1, characterized in that: Determine whether the vehicle is in a rolling state; Specifically include: When the vehicle is in a forward gear, if the motor speed is less than the second set speed and lasts for a second set time, or if the motor speed is less than the third set speed, it is determined to be slipping; The second set speed and the third set speed are both negative values, and the second set speed is greater than the third set speed.

3. The uphill assist control method based on motor control according to claim 2, characterized in that: Determining whether the vehicle is in a rolling state; further comprising: When the vehicle is in reverse gear, if the motor speed is greater than the fourth set speed for a third set time, or if the motor speed is greater than the fifth set speed, it is determined to be slipping; wherein the fourth set speed and the fifth set speed are both positive values ​​and the fourth set speed is less than the fifth set speed.

4. The uphill assist control method based on motor control according to claim 1, characterized in that: Calculate the current motor acceleration when the vehicle is in forward or reverse gear and the motor controller detects that the brake pedal is released and the accelerator pedal opening and closing degree is zero.

5. The uphill assist control method based on motor control according to claim 1, characterized in that: After completing the loading of the hill-holding torque, the motor controller controls the motor to operate at zero speed through the proportional-integral controller to realize the vehicle's uphill assist function; specifically, the motor is controlled to operate at zero speed through the proportional-integral controller PI; the target speed is 0rpm, and the difference between the current motor speed and the target speed is used as the input of the PI controller, and the output is the motor torque through proportional-integral adjustment.

6. A hill-climbing assist control system based on motor control, adopting a hill-climbing assist control method based on motor control according to any one of claims 1 to 5, characterized in that: include: A judgment module is configured to: judge whether the vehicle is in a rolling state, and if so, enter the calculation module; A calculation module is configured to: calculate the current motor acceleration; The table lookup module is configured to: look up the hill-holding torque corresponding to the current motor acceleration from a pre-defined hill-holding torque table according to the current motor acceleration; and the motor controller implements the loading of the hill-holding torque to prevent the vehicle from rolling; The control module is configured as follows: after the motor controller completes the loading of the hill-holding torque, it controls the motor to operate at zero speed through the proportional-integral controller to realize the vehicle uphill assist function.

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