EPS power assist mode control method, device, electronic device, and storage medium

Abstract

The present invention discloses an EPS power-assistance mode control method, device, electronic device, and storage medium, wherein the method includes the following steps: obtaining the current vehicle speed, lateral acceleration, and steering torque of the steering wheel; determining a proportionality coefficient based on the vehicle speed and lateral acceleration; and determining a final power-assistance current based on a first power-assistance current in a first power-assistance mode and a second power-assistance current in a second power-assistance mode under the vehicle speed and steering torque conditions, as well as the proportionality coefficient. Beneficial effects: Based on the vehicle speed, lateral acceleration, and the steering torque gradient, a characteristic indicator for evaluating vehicle handling stability, the vehicle stability characteristics and the driver's hand-feel feedback strength are determined, and then the proportionality coefficients between different steering power-assistance modes are derived, ultimately achieving a moderate correction of the driver's steering force sense and ensuring flexible and smooth force sense changes.

Description

Technical Field

[0001] The present invention relates to the technical field of driving control methods, and in particular to an EPS power assist mode control method, device, electronic device and storage medium. Background Art

[0002] As a system that directly interacts with the driver, the steering system must constantly sense the driver's lateral control needs and provide timely feedback on vehicle and road conditions. Different drivers have different driving styles and require varying levels of steering effort. The EPS (Electric Power Steering) system primarily monitors the driver's steering torque. The system uses the input torque to control the motor current output corresponding to the power steering torque. The greater the EPS power steering torque, the more negative feedback is sent to the steering wheel through the system, resulting in a lighter steering effort perceived by the driver.

[0003] Existing technologies are broadly categorized into two types. One is a fixed, single-steering EPS system, where the EPS uses steering torque information from the steering torque sensor to provide a single, fixed level of assistance. In this state, the driver's steering effort to control the vehicle's lateral motion is fixed, requiring adaptation. The other is a system with multiple preset assist modes, each corresponding to a different level of assistance, resulting in varying degrees of feedback to the driver. However, each mode requires adjustment, either independently or in conjunction with the driving mode. These multi-mode functions are activated and deactivated under certain vehicle speed and steering torque conditions.

[0004] Different modes of power assistance at the same vehicle speed, the existing technical solutions for different driver hand force requirements are often implemented through multi-mode calibration. In different steering modes, the driver's steering control force is different. In Normal mode, the EPS power assistance is greater, and the driver feels the steering force is lighter. In Sport mode, the EPS motor's power assistance is smaller, requiring the driver to have increased control force, and the steering force style is more stable.

[0005] However, within the same fixed steering assist mode, the vehicle's lateral acceleration and steering torque characteristics under steady-state turning conditions are fixed. However, under conditions with varying rates of lateral acceleration, the steering force gradient varies. Switching between the two modes requires external switching commands, and the steering force remains relatively fixed, resulting in a relatively uniform feel.

[0006] Furthermore, at low speeds, with a smaller turning radius and lower lateral acceleration, the driver desires a relatively smooth change in steering torque, but also a certain torque gradient. However, in either Sport or Normal mode, the torque gradient varies. For example, in Sport mode, the torque gradient is larger, resulting in a larger and faster increase in steering torque, which can lead to a heavy steering feel. Even in this mode, the driver needs to minimize steering effort while ensuring vehicle steering stability, rather than maintaining the heavy feel of Sport mode.

[0007] Similarly, under conditions of high speed and large turning radius, the vehicle's lateral acceleration is large. At this time, the power assist in Normal mode is large, and the driver feels less steering wheel force. Although the steering wheel force is small and the feel is lighter while ensuring vehicle steering stability, vehicle stability is more important under this condition. At this time, greater torque is required under lateral acceleration, that is, the steering wheel torque is controlled by the driver's greater hand force.

[0008] Similarly, when the vehicle moves in a serpentine manner at different steering angles, or during emergency obstacle avoidance, and the vehicle state changes from low lateral acceleration to high lateral acceleration, under the same fixed steering mode, the corresponding steering wheel steering torque gradient change is certain, which cannot meet the requirements of ensuring steering comfort under small lateral driving conditions, and actively switches and transitions based on measuring stability under large lateral acceleration.

[0009] Different power-assistance modes correspond to the driver's choice and are a passive adjustment mechanism. The driving feel of the two modes is fixed. When the lateral acceleration increases from zero, it means that the vehicle is turning from a straight-ahead state. At this time, the vehicle has a larger lateral force in a shorter period of time. If the steering torque is too small, the driver can easily achieve the required steering requirements. However, due to the light steering force, oversteering is prone to occur, which is more dangerous at higher speeds or when specific obstacle avoidance requirements are required. Summary of the Invention

[0010] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide an EPS power assist mode control method, device, electronic device and storage medium.

[0011] To achieve this object, the present invention adopts the following technical solutions:

[0012] In a first aspect, a method for controlling an EPS power assist mode includes the following steps:

[0013] Get the current vehicle speed, lateral acceleration and steering torque of the steering wheel;

[0014] determining a proportionality coefficient according to the vehicle speed and the lateral acceleration;

[0015] A final assist current is determined according to the first assist current in the first assist mode and the second assist current in the second assist mode under the vehicle speed and the steering torque conditions and the proportional coefficient.

[0016] In one embodiment, the step of determining a proportionality coefficient based on the vehicle speed and the lateral acceleration includes:

[0017] Obtaining a first functional relationship between the lateral acceleration and the steering torque gradient under various vehicle speed conditions in a first power-assist mode, and a second functional relationship between the lateral acceleration and the steering torque gradient under various vehicle speed conditions in a second power-assist mode;

[0018] Under a preset vehicle speed condition in the test mode, a test mapping relationship between lateral acceleration and steering torque gradient is calibrated on the actual vehicle, and the steering torque gradient corresponding to any lateral acceleration in the test mapping relationship is made to be between the two steering torque gradients corresponding to the first functional relationship and the second functional relationship under the same preset vehicle speed and lateral acceleration conditions;

[0019] A proportional coefficient is determined according to the first functional relationship, the second functional relationship, and the test mapping relationship.

[0020] In one embodiment, the step of calibrating a test mapping relationship between lateral acceleration and steering torque gradient on a real vehicle under the preset vehicle speed condition in the test mode includes:

[0021] The preset vehicle speed condition is determined according to the vehicle speed range.

[0022] In one embodiment, vehicle speed intervals are set within different vehicle speed ranges according to the size of the vehicle speed difference.

[0023] In one embodiment, the step of setting the vehicle speed interval according to the size of the vehicle speed difference within different vehicle speed ranges includes:

[0024] A high speed range and a low speed range are preset, and the speed difference during the vehicle speed setting period in the high speed range is smaller than the speed difference during the vehicle speed setting period in the low speed range.

[0025] In one embodiment, the step of determining the test mode includes:

[0026] Determine a functional relationship f1(x) between the steering torque and the EPS assist current in a first assist mode, and a functional relationship f2(x) between the steering torque and the EPS assist current in a second assist mode;

[0027] The functional relationship g(x) between the steering torque and the EPS assist current in the test mode satisfies:

[0028] g(x)=[f1(x)+f2(x)] / 2.

[0029] In one embodiment, the step of determining the proportional coefficient according to the first functional relationship, the second functional relationship, and the test mapping relationship includes:

[0030] Taking a plurality of lateral accelerations, corresponding to each of the lateral accelerations, using the steering torque gradient determined by the first functional relationship and the second functional relationship as a lower boundary value and an upper boundary value, respectively, and using the steering torque gradient determined by the test mapping relationship as a proportional coefficient input value;

[0031] Dividing the difference between the proportional coefficient input value and the lower boundary by the difference between the upper boundary value and the lower boundary value to determine the initial proportional coefficient corresponding to the lateral acceleration;

[0032] The initial proportional coefficients corresponding to the lateral accelerations are averaged and determined as the proportional coefficient.

[0033] In one embodiment, the mean calculation is a weighted mean calculation, and each of the initial proportional coefficients corresponds to a weighting coefficient;

[0034] The weighting coefficient of the initial proportional coefficient corresponding to the lateral acceleration less than the calibrated lateral acceleration is greater than the weighting coefficients of the initial proportional coefficients corresponding to the other lateral accelerations.

[0035] In one embodiment, the step of determining the final power-assisting current according to the first power-assisting current in the first power-assisting mode and the second power-assisting current in the second power-assisting mode and the proportional coefficient under the vehicle speed and the steering torque comprises:

[0036] The final assist current is determined using a convex combination algorithm based on the first assist current calibrated in the first assist mode under the current vehicle speed and the steering torque, the second assist current in the second assist mode, the first parameter, the second parameter, and the proportional coefficient.

[0037] In one embodiment, before determining the proportionality coefficient based on the vehicle speed and the lateral acceleration, the method further includes the following steps:

[0038] It is determined that the vehicle speed is within a preset speed range and the lateral acceleration is within a preset acceleration range.

[0039] In one embodiment, the step of determining that the vehicle speed is within a preset speed range and the lateral acceleration is within a preset acceleration range includes:

[0040] determining that the vehicle speed is above a first preset vehicle speed, or that the vehicle speed is below a second preset vehicle speed, wherein the first preset vehicle speed is greater than the second preset vehicle speed;

[0041] It is determined that the lateral acceleration is less than a preset acceleration.

[0042] In a second aspect, an EPS power assist mode control device includes:

[0043] The first module is used to obtain the current vehicle speed, lateral acceleration and steering torque of the steering wheel;

[0044] A second module is configured to determine a proportionality coefficient based on the vehicle speed and the lateral acceleration;

[0045] The third module is used to determine a final power-assisting current according to the first power-assisting current in the first power-assisting mode and the second power-assisting current in the second power-assisting mode and the proportional coefficient under the vehicle speed and the steering torque conditions.

[0046] In a third aspect, an electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the EPS power assist mode control method described above when executing the computer program.

[0047] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions enable the computer to execute the steps of the EPS power assist mode control method as described above.

[0048] The beneficial effects of the present invention are as follows: for the EPS power-assist mode control method, device, electronic device and computer-readable storage medium, by obtaining the current vehicle speed, lateral acceleration and steering torque of the steering wheel; determining the proportional coefficient according to the vehicle speed and lateral acceleration; determining the final power-assist current according to the first power-assist current in the first power-assist mode and the second power-assist current in the second power-assist mode and the proportional coefficient under the vehicle speed and steering torque conditions; judging the vehicle stability characteristics and the driver's hand-feel feedback strength according to the vehicle speed, lateral acceleration and the steering torque gradient, a characteristic indicator for evaluating the vehicle handling stability, and then obtaining the proportional coefficient between different steering power-assist modes, and finally achieving the moderate correction of the driver's steering force sense and ensuring flexible and smooth force sense changes.

[0049] Additional aspects and advantages of the present application will be given in part in the following description, which will become apparent from the following description, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0051] Figure 1 This is a common EPS composition diagram;

[0052] Figure 2 is a flow chart of the EPS power assist mode control method provided in this embodiment;

[0053] Figure 3 A graph showing the functional relationship between lateral acceleration and steering torque gradient is shown;

[0054] Figure 4 is a schematic diagram of the EPS power assist mode control device provided in this embodiment;

[0055] Figure 5 It is a structural diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0056] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0057] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0058] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a," "an," "said," and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0059] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless specifically defined as in the examples of this application.

[0060] This embodiment provides an EPS power assist mode control method, which is applied to automobile EPS. Figure 1 This is a common EPS composition diagram, such as Figure 1 As shown, EPS consists of a torque sensor, EPS electronic control unit, motor and reducer.

[0061] The torque sensor is a sensor that detects the driver's steering torque and is an important device for detecting the basic information required by EPS. The torque sensor usually consists of a torsion bar installed on the steering shaft and a sensor that detects the torsion angle of the torsion bar.

[0062] The torque sensor in this embodiment is of magnetic induction type. Specifically, the relative positions of the detection coil and the compensation coil installed at the upper and lower positions of the torsion bar change with the torsion bar's twisting, and the corresponding magnetic circuit changes are obtained through the detection coil arranged on the outside.

[0063] It should be noted that this embodiment is not limited to the Hall integrated circuit type and dual rotary transformer type torque sensors.

[0064] The ESP electronic unit consists of a microcontroller for control, an integrated circuit (sometimes a microcontroller) for monitoring, the motor drive circuit (drive circuit and conversion circuit), relays for opening and closing the motor and power paths, and interface circuits for receiving external signals. The motor drive circuit's function is to implement PWM control to turn the power components on and off.

[0065] According to the type of motor and the power assist position, EPS can be divided into three types: steering column power assist, gear power assist, and rack power assist.

[0066] Among them, the motor of the steering column power-assisted type includes a column shaft and a motor. The motor of the gear power-assisted type includes a motor and a pinion. The rack power-assisted type motor is divided into four types, including rack coaxial power-assisted type, rack cross power-assisted type, rack parallel power-assisted type and double pinion power-assisted type. In the rack coaxial power-assisted type, the rack and motor are coaxially arranged. In the rack cross power-assisted type, the rack and motor are cross-arranged. In the rack parallel power-assisted type, the rack and motor are arranged axially in parallel. In the double pinion power-assisted type, two pinions are added to the original motor, and the two pinions and the rack are arranged in parallel.

[0067] Column-assisted EPS is widely adopted due to its low cost. Pinion-assisted EPS places the motor near the gears. Rack-assisted EPS uses a rack close to the tires as the final output, minimizing power loss. Furthermore, the actuator is located farther from the driver, resulting in lower noise and vibration. It is primarily used in high-end vehicles. Rack-assisted EPS's actuator and controller are located within the engine compartment, requiring heat resistance and waterproofing, which increases system costs.

[0068] The control method provided in this embodiment is not limited to being applied to an EPS composed of any of the above-mentioned torque sensors, EPS electronic control units, motors, and speed reducers.

[0069] Figure 2 This is a flow chart of the EPS power assist mode control method provided in this embodiment.

[0070] The method includes steps S10 to S30, wherein step S10 is to obtain the current vehicle speed, lateral acceleration and steering torque of the steering wheel.

[0071] In this embodiment, a vehicle speed signal is collected by a vehicle speed sensor, a lateral acceleration signal is collected by a lateral acceleration sensor, and a steering wheel torque signal is collected by a torque sensor.

[0072] Step S20: Determine a proportionality coefficient based on the vehicle speed and the lateral acceleration. It should be noted that the proportionality coefficient is a decimal between 0 and 1.

[0073] Specifically, step S20 includes steps S201-S203.

[0074] S201: Obtain a first functional relationship between lateral acceleration and steering torque gradient at various vehicle speeds in a first power-assist mode, and a second functional relationship between lateral acceleration and steering torque gradient at various vehicle speeds in a second power-assist mode. In this embodiment, the first power-assist mode is the Normal mode, and the second power-assist mode is the Sport mode.

[0075] It can be understood that the functional relationship between the lateral acceleration and the steering torque gradient is determined based on different vehicle speed conditions.

[0076] For example, at a constant vehicle speed of 20 km / h, the functional relationship between lateral acceleration and steering torque gradient is determined. In this case, one lateral acceleration corresponds to one steering torque gradient, and the lateral acceleration and steering torque gradients are mapped one to one. At 30 km / h, another set of functional relationships between lateral acceleration and steering torque gradients exists. This embodiment is not limited to determining the functional relationship between lateral acceleration and steering torque gradients under different vehicle speed conditions of 10 km / h-120 km / h.

[0077] In this embodiment, the second functional relationship between lateral acceleration and steering torque gradient at each vehicle speed in both the first and second power-assist modes is a pre-set continuous functional relationship. In other words, in this continuous function, the horizontal axis represents lateral acceleration, and the vertical axis represents steering torque gradient. The horizontal axis represents lateral acceleration, and the vertical axis represents steering torque gradient. The horizontal axis represents lateral acceleration, and the vertical axis represents steering torque gradient.

[0078] Figure 3 The functional relationship between lateral acceleration and steering torque gradient is shown in FIG. Figure 3 As shown in the figure, the functions of lateral acceleration and steering torque gradient at three different vehicle speeds in the first power-assist mode are shown, specifically, the functions of lateral acceleration and steering torque gradient at 100 km / h, 60 km / h and 10 km / h, respectively. Figure 3 It can be seen that in this mode, as the vehicle speed increases, the steering torque gradient becomes smaller at the same lateral acceleration, and at the same vehicle speed, as the lateral acceleration increases, the steering torque gradient becomes smaller.

[0079] Step S202: Under the preset vehicle speed condition of the test mode, the actual vehicle calibrates a test mapping relationship between lateral acceleration and steering torque gradient, and makes the steering torque gradient corresponding to any lateral acceleration in the test mapping relationship fall between the two steering torque gradients corresponding to the first functional relationship and the second functional relationship under the same preset vehicle speed and the said lateral acceleration conditions.

[0080] When a vehicle is navigating a curved path, i.e., when lateral steering torque is output, the vehicle will generate a corresponding lateral centripetal acceleration, corresponding to a virtual turning radius. The greater the lateral acceleration, the greater the corresponding steering holding torque, i.e., the greater the steering torque required for steering. Vehicle operational stability testing is conducted in two ways: one with a fixed turning radius of 50m, and the other with a fixed steering angle. The lateral acceleration-steering torque gradient is used to assess the appropriateness of the vehicle's steering force gradient. If the gradient is too large, i.e., the steering torque increases significantly with increasing lateral acceleration, the driver's hand force will change significantly, the corresponding steering holding force will be greater, and the driver will feel the steering is heavy. When the steering torque increases with increasing lateral acceleration, the increase in steering torque is smaller (the gradient is smaller), and the driver feels the steering force is lighter.

[0081] Step S202 further includes a test mode determination step. Specifically, the test mode determination step includes:

[0082] Determine a functional relationship f1(x) between the steering torque and the EPS assist current in a first assist mode, and a functional relationship f2(x) between the steering torque and the EPS assist current in a second assist mode;

[0083] The functional relationship g(x) between steering torque and EPS assist current in the test mode satisfies:

[0084] g(x)=[f1(x)+f2(x)] / 2.

[0085] During the actual vehicle calibration, the EPS is output according to the new assist current rule. During the calibration process, the steering torque gradient corresponding to any lateral acceleration in the third mapping relationship is between the two steering gradients corresponding to the first mapping relationship and the second mapping relationship under the same preset vehicle speed and lateral acceleration conditions.

[0086] It is understandable that since the functional relationship between the steering torque and EPS assist current in the first and second assist modes has been calibrated, the EPS output current in the test mode can also be calibrated, and on this basis, actual vehicle testing can be carried out.

[0087] It should be noted that, since this is a real-vehicle calibration, to improve the calibration efficiency of the test mapping in step S202, vehicle speed conditions are established based on vehicle speed ranges. Specifically, by defining speed ranges, the same lateral acceleration and steering torque gradient mapping relationship is determined for any speed within the speed range. This significantly reduces the calibration effort and improves calibration efficiency.

[0088] For example, within a vehicle speed range of 20 km / h to 24 km / h, the same lateral acceleration and steering torque gradient mapping relationship is determined. When the vehicle speed is at any speed value within the 20 km / h to 24 km / h speed range, the same mapping relationship is determined.

[0089] It can be understood that the above embodiment is based on the actual vehicle calibration to set the vehicle speed range with a speed difference of 5 km / h to determine the corresponding mapping relationship between the lateral acceleration and the steering torque gradient.

[0090] Furthermore, considering that different reaction time requirements may exist during the actual vehicle calibration at different vehicle speeds, and different reaction times may affect different braking distances, in this embodiment, the speed intervals set during the actual vehicle calibration are not completely the same.

[0091] Specifically, a high speed range and a low speed range are preset, wherein the speed difference between the individual speed intervals in the low speed range is greater than the speed difference between the individual speed intervals in the high speed range.

[0092] For example, a vehicle speed of 30 km / h and below is preset as a low speed range, and a vehicle speed of 90 km / h and above is set as a high speed range.

[0093] In the low speed range, a speed range is set with a speed difference of 10km / h: 0-10km / h, 10-20km / h, 20km / h-30km / h.

[0094] Within the high-speed range, set a speed range with a speed difference of 5km / h: 90km / h-95km / h, 95km / h-100km / h, 100km / h-105km / h, 105km / h-110km / h and so on.

[0095] It should be noted that the specific setting of the high-speed range and the low-speed range can be calibrated according to actual conditions or test conditions, and different vehicle speed differences can also be set within different ranges. This embodiment is not limited to this.

[0096] Step S203: Determine a proportional coefficient according to the first functional relationship, the second functional relationship, and the test mapping relationship.

[0097] Specifically, step S203 includes: S2031-S2034.

[0098] S2031. Determine multiple target lateral accelerations based on the test results.

[0099] In this embodiment, the following target lateral acceleration is determined: 0.5 m / s 2 , 1m / s 2 , 1.5m / s 2 , 2m / s 2 , 2.5m / s 2 , 3m / s 2 、3.5m / s 2 , 4m / s 2 , 4.5m / s 2 , 5m / s 2 , 5.5m / s 2 , 6m / s 2 .

[0100] S2032. For each lateral acceleration, substitute the first functional relationship and the second functional relationship to determine the steering torque gradient respectively, and use them as the lower boundary value and the upper boundary value, and use the steering torque gradient determined by the test mapping relationship as the proportional coefficient input value.

[0101] At 1m / s 2 For example, substitute the first and second functional relationships into the two steering torque gradients determined as the lower boundary value y1 and the upper boundary value y2. It can be understood that the upper boundary value y2 is greater than the lower boundary value y1. The steering torque gradient determined by the experimental mapping relationship is used as the proportional coefficient input value x1.

[0102] S2033: Divide the difference between the scale factor input value x1 and the lower boundary y2 by the difference between the upper boundary value y1 and the lower boundary value y2 to determine the initial scale factor corresponding to the lateral acceleration. That is, it is determined to correspond to 1m / s2 The initial ratio k1.

[0103] That is, after 0.5m / s 2 , 1.5m / s 2 , 2m / s 2 , 2.5m / s 2 , 3m / s 2 、3.5m / s 2 , 4m / s 2 , 4.5m / s 2 , 5m / s 2 , 5.5m / s 2 , 6m / s 2 For each lateral acceleration, determine the corresponding initial ratio k2...k11.

[0104] S204 , calculating an average of the initial proportional coefficients corresponding to the lateral accelerations and determining the average as the proportional coefficient.

[0105] For example, the sum of k1, k2, ..., k11 may be divided by 11 to obtain the final scaling factor.

[0106] In this embodiment, the proportional coefficient is determined by weighted mean calculation.

[0107] Each initial proportional coefficient corresponds to a weighting coefficient; wherein the weighting coefficient of the initial proportional coefficient corresponding to the lateral acceleration less than the calibrated lateral acceleration is larger than the weighting coefficients of the initial proportional coefficients corresponding to the remaining lateral accelerations.

[0108] In this embodiment, the calibrated lateral acceleration is set to 3m / s 2 , taking into account that when the lateral acceleration is small, the steering torque gradient is larger, therefore, in this embodiment, 0.5m / s 2 -3 m / s 2 The weighted coefficient of the initial proportional coefficient is greater than 3m / s 2 -6 m / s 2 By adding the weighting coefficient, when calculating the mean, the initial proportional coefficient that is less than the calibrated lateral acceleration has a greater impact on the final proportional coefficient, and the actual result will have a better effect.

[0109] It should be noted that the weighting coefficient can be set first and then adjusted according to the actual vehicle calibration.

[0110] It should be noted that this method can be performed under specific conditions. In other words, outside of the specific conditions, the EPS is still controlled in the original first power-assistance mode and the second power-assistance mode.

[0111] Before step S20 , it is determined that the vehicle speed is within a preset speed range and the lateral acceleration is within a preset acceleration range.

[0112] Specifically, the above-mentioned condition determination includes: determining that the vehicle speed is above a first preset speed, or below a second preset speed, wherein the first preset speed is greater than the second preset speed; and determining that the lateral acceleration is less than a preset acceleration.

[0113] It will be appreciated that this method divides the vehicle speed into three intervals: below the second preset speed, above the first preset speed, and between the second preset speed and the first preset speed. This method also divides the vehicle speed into two intervals based on lateral acceleration. When the current vehicle speed is above the first preset speed and the lateral acceleration is less than the preset acceleration, or when the vehicle speed is below the second preset speed and the lateral acceleration is less than the preset acceleration, step S30 is performed.

[0114] In this embodiment, the first preset vehicle speed is 90 km / h, the second preset vehicle speed is 30 km / h, and the preset lateral acceleration is set to 3 m / s 2 .

[0115] For example, at a speed of 100 km / h and a lateral acceleration of 2 m / s 2 , the corresponding steering wheel torque increases relatively quickly, that is, maintaining a certain sense of steering resistance and maintaining the stability of the vehicle.

[0116] At 10km / h, the lateral acceleration is 2m / s 2 , reduce the torque change gradient, maintain appropriate steering force, and ensure comfortable steering force.

[0117] It should be noted that the first preset vehicle speed, the second preset vehicle speed and the preset lateral acceleration are not limited to the values in the above embodiment.

[0118] Step S30 : determining a final power-assisting current according to the first power-assisting current in the first power-assisting mode and the second power-assisting current in the second power-assisting mode and a proportional coefficient under vehicle speed and steering torque conditions.

[0119] It can be understood that the power assist currents due to the two current power assist modes can be determined based on the two power assist currents under the current vehicle speed and steering torque conditions and the proportional coefficient determined in step S20 .

[0120] Specifically, step S30 includes determining the final assist current using a convex combination algorithm based on the first assist current calibrated in the first assist mode under the current vehicle speed and steering torque, the second assist current in the second assist mode, the first parameter, the second parameter, and the proportional coefficient.

[0121] For example, if the current vehicle speed is 90 km / h and the steering torque is 1.5 N·m, the first power assist current of the first power assist mode corresponding to this condition is determined to be I A , the second assist current of the second assist mode is I B , the first parameter is 0, the second parameter is 1, the proportional coefficient k, based on the above data, use the convex combination algorithm to determine the final assist current I:

[0122] I=k·I A +(1-k)·I B .

[0123] It should be noted that after the final assist current is determined, the current output is based on the assist current, which can be different from the current first assist mode or second assist mode. That is, even if one of the assist modes is selected, the final output current is close to that assist mode.

[0124] This control method determines the vehicle stability characteristics and the driver's hand-feel feedback strength based on vehicle speed, lateral acceleration, and the steering torque gradient, a characteristic indicator used to evaluate vehicle handling stability. It then derives the proportional coefficient between different steering assist modes, ultimately achieving a moderate correction of the driver's steering force sense to ensure flexible and smooth force changes.

[0125] This embodiment also provides an EPS power assist mode control device, Figure 4 Schematic diagram of the EPS power assist mode control device provided in this embodiment.

[0126] like Figure 4 As shown, the EPS power assist mode control device includes a first module 41 , a second module 42 and a third module 43 .

[0127] The first module 41 is used to obtain the current vehicle speed, lateral acceleration and steering torque of the steering wheel.

[0128] The second module 42 is configured to determine a proportionality coefficient according to the vehicle speed and the lateral acceleration.

[0129] The third module 43 is configured to determine a final assist current according to the first assist current in the first assist mode and the second assist current in the second assist mode under the vehicle speed and the steering torque conditions and the proportional coefficient.

[0130] It should be noted that the EPS power assist mode control device provided in this embodiment can also be a computer program (including program code) running in a computer device. For example, the EPS power assist mode control device is an application program that can be used to execute the corresponding steps in the above method provided in the embodiment of this application.

[0131] In some feasible implementations, the EPS power-assisting mode control device provided in this embodiment can be implemented by a combination of software and hardware. As an example, the EPS power-assisting mode control device of the embodiment of the present application can be a processor in the form of a hardware decoding processor, which is programmed to execute the EPS power-assisting mode control method provided in the embodiment of the present application. For example, the processor in the form of a hardware decoding processor can adopt one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs) or other electronic components.

[0132] In some feasible implementations, the EPS power assist mode control device provided in this embodiment can be implemented in software, which can be software in the form of programs and plug-ins, and include a series of modules to implement the control method provided in the embodiment of the present invention.

[0133] The EPS power-assist mode control device provided in this embodiment obtains the current vehicle speed, lateral acceleration and steering torque of the steering wheel; determines the proportional coefficient according to the vehicle speed and lateral acceleration; determines the final power-assist current according to the first power-assist current in the first power-assist mode and the second power-assist current in the second power-assist mode and the proportional coefficient under the vehicle speed and steering torque conditions, determines the vehicle stability characteristics and the driver's hand-feel feedback strength according to the vehicle speed, lateral acceleration and the steering torque gradient, a characteristic indicator for evaluating the vehicle handling stability, and then derives the proportional coefficient between different steering power-assist modes, ultimately achieving moderate correction of the driver's steering force sense and ensuring flexible and smooth force sense changes.

[0134] The embodiment of the present application also provides an electronic device, Figure 5 is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. Figure 5As shown, the electronic device 1000 in this embodiment may include: a processor 1001, a network interface 1004 and a memory 1005. In addition, the above-mentioned electronic device 1000 may also include: a user interface 1003, and at least one communication bus 1002. The communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), a keyboard (Keyboard), and the user interface 1003 may optionally include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1004 may be a high-speed RAM memory, or a non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 1005 may optionally be at least one storage device located away from the aforementioned processor 1001. As Figure 5 As shown, the memory 1005 as a computer-readable storage medium may include an operating system, a network communication module, a user interface module, and a device control application.

[0135] like Figure 5 In the electronic device 1000 shown, the network interface 1004 can provide network communication functions; the user interface 1003 is mainly used to provide an interface for user input; and the processor 1001 can be used to call the device control application stored in the memory 1005 to achieve:

[0136] Get the current vehicle speed, lateral acceleration and steering torque of the steering wheel;

[0137] determining a proportionality coefficient according to the vehicle speed and the lateral acceleration;

[0138] A final assist current is determined according to the first assist current in the first assist mode and the second assist current in the second assist mode under the vehicle speed and the steering torque conditions and the proportional coefficient.

[0139] It should be understood that in some feasible embodiments, the processor 1001 may be a central processing unit (CPU). The processor may also be another general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. The general-purpose processor may be a microprocessor or any conventional processor. The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store device type information.

[0140] In a specific implementation, the electronic device 1000 can execute the implementation methods provided by the various steps of the above control method through its built-in functional modules. For details, please refer to the implementation methods provided by the above steps, which will not be repeated here.

[0141] The electronic device provided in this embodiment obtains the current vehicle speed, lateral acceleration and steering torque of the steering wheel; determines the proportional coefficient according to the vehicle speed and lateral acceleration; determines the final assist current according to the first assist current in the first assist mode and the second assist current in the second assist mode and the proportional coefficient under the vehicle speed and steering torque conditions, and determines the vehicle stability characteristics and the driver's hand feel feedback strength according to the vehicle speed, lateral acceleration and the steering torque gradient, a characteristic indicator for evaluating the vehicle handling stability, and then derives the proportional coefficient between different steering assist modes, ultimately achieving a moderate correction of the driver's steering force sense and ensuring flexible and smooth force sense changes.

[0142] An embodiment of the present application also provides a computer-readable storage medium, which stores a computer program and is executed by a processor to implement the various steps in the EPS power assist mode control method in the above embodiment. For details, please refer to the implementation methods provided in the above steps, which will not be repeated here.

[0143] The computer-readable storage medium provided in this embodiment obtains the current vehicle speed, lateral acceleration and steering torque of the steering wheel; determines the proportional coefficient according to the vehicle speed and lateral acceleration; determines the final assist current according to the first assist current in the first assist mode and the second assist current in the second assist mode and the proportional coefficient under the vehicle speed and steering torque conditions, determines the vehicle stability characteristics and the driver's hand feel feedback strength according to the vehicle speed, lateral acceleration and the steering torque gradient, a characteristic indicator for evaluating the vehicle handling stability, and then derives the proportional coefficient between different steering assist modes, ultimately achieving a moderate correction of the driver's steering force sense and ensuring flexible and smooth force sense changes.

[0144] It should be understood that although the steps in the flowcharts of the accompanying drawings are shown in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the flowcharts of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0145] The above description is only part of the implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A EPS power assist mode control method, characterized in that: The following steps are involved: Get the current vehicle speed, lateral acceleration and steering torque of the steering wheel; determining a proportionality coefficient according to the vehicle speed and the lateral acceleration; determining a final power-assisting current according to the first power-assisting current in the first power-assisting mode and the second power-assisting current in the second power-assisting mode and the proportional coefficient under the vehicle speed and the steering torque; The step of determining the proportionality coefficient according to the vehicle speed and the lateral acceleration includes: Obtaining a first functional relationship between the lateral acceleration and the steering torque gradient under various vehicle speed conditions in a first power-assist mode, and a second functional relationship between the lateral acceleration and the steering torque gradient under various vehicle speed conditions in a second power-assist mode; Under a preset vehicle speed condition in the test mode, a test mapping relationship between lateral acceleration and steering torque gradient is calibrated on the actual vehicle, and the steering torque gradient corresponding to any lateral acceleration in the test mapping relationship is made to be between the two steering torque gradients corresponding to the first functional relationship and the second functional relationship under the same preset vehicle speed and lateral acceleration conditions; determining a proportional coefficient according to the first functional relationship, the second functional relationship, and the test mapping relationship; The step of determining the proportional coefficient according to the first functional relationship, the second functional relationship, and the test mapping relationship includes: Taking a plurality of lateral accelerations, corresponding to each of the lateral accelerations, using the steering torque gradient determined by the first functional relationship and the second functional relationship as a lower boundary value and an upper boundary value, respectively, and using the steering torque gradient determined by the test mapping relationship as a proportional coefficient input value; Dividing the difference between the proportional coefficient input value and the lower boundary by the difference between the upper boundary value and the lower boundary value to determine the initial proportional coefficient corresponding to the lateral acceleration; The initial proportional coefficients corresponding to the lateral accelerations are averaged and determined as the proportional coefficient.

2. The EPS power assist mode control method according to claim 1, characterized in that: The step of calibrating a test mapping relationship between lateral acceleration and steering torque gradient on a real vehicle under a preset vehicle speed condition in a test mode comprises: The preset vehicle speed condition is determined according to the vehicle speed range.

3. The EPS power assist mode control method according to claim 2, characterized in that: The speed interval is set according to the speed difference in different speed ranges.

4. The EPS power assist mode control method according to claim 3, characterized in that: The step of setting the vehicle speed interval according to the size of the vehicle speed difference within different vehicle speed ranges includes: A high speed range and a low speed range are preset, and the speed difference during the vehicle speed setting period in the high speed range is smaller than the speed difference during the vehicle speed setting period in the low speed range.

5. The EPS power assist mode control method according to claim 3, characterized in that: The steps of determining the test mode include: Determine a functional relationship f1(x) between the steering torque and the EPS assist current in a first assist mode, and a functional relationship f2(x) between the steering torque and the EPS assist current in a second assist mode; The functional relationship g(x) between the steering torque and the EPS assist current in the test mode satisfies: g(x)=[f1(x)+f2(x)] / 2.

6. The EPS power assist mode control method according to claim 1, characterized in that: The mean calculation is a weighted mean calculation, and each of the initial proportional coefficients corresponds to a weighted coefficient; The weighting coefficient of the initial proportional coefficient corresponding to the lateral acceleration less than the calibrated lateral acceleration is greater than the weighting coefficients of the initial proportional coefficients corresponding to the other lateral accelerations.

7. The EPS power assist mode control method according to claim 1, characterized in that: The step of determining the final power-assisting current according to the first power-assisting current in the first power-assisting mode and the second power-assisting current in the second power-assisting mode and the proportional coefficient comprises: The final assist current is determined using a convex combination algorithm based on the first assist current calibrated in the first assist mode under the current vehicle speed and the steering torque, the second assist current in the second assist mode, the first parameter, the second parameter, and the proportional coefficient.

8. The EPS power assist mode control method according to any one of claims 1 to 7, characterized in that: Before determining the proportionality coefficient according to the vehicle speed and the lateral acceleration, the method further includes the following steps: It is determined that the vehicle speed is within a preset speed range and the lateral acceleration is within a preset acceleration range.

9. The EPS power assist mode control method according to claim 8, characterized in that: The step of determining that the vehicle speed is within a preset speed range and the lateral acceleration is within a preset acceleration range includes: determining that the vehicle speed is above a first preset vehicle speed, or that the vehicle speed is below a second preset vehicle speed, wherein the first preset vehicle speed is greater than the second preset vehicle speed; It is determined that the lateral acceleration is less than a preset acceleration.

10. An EPS power assist mode control device, characterized in that: include: The first module is used to obtain the current vehicle speed, lateral acceleration and steering torque of the steering wheel; A second module is configured to determine a proportionality coefficient based on the vehicle speed and the lateral acceleration; a third module, configured to determine a final power-assisting current according to the first power-assisting current in the first power-assisting mode and the second power-assisting current in the second power-assisting mode and the proportional coefficient under the vehicle speed and the steering torque; The step of determining the proportionality coefficient according to the vehicle speed and the lateral acceleration includes: Obtaining a first functional relationship between the lateral acceleration and the steering torque gradient under various vehicle speed conditions in a first power-assist mode, and a second functional relationship between the lateral acceleration and the steering torque gradient under various vehicle speed conditions in a second power-assist mode; Under a preset vehicle speed condition in the test mode, a test mapping relationship between lateral acceleration and steering torque gradient is calibrated on the actual vehicle, and the steering torque gradient corresponding to any lateral acceleration in the test mapping relationship is made to be between the two steering torque gradients corresponding to the first functional relationship and the second functional relationship under the same preset vehicle speed and lateral acceleration conditions; determining a proportional coefficient according to the first functional relationship, the second functional relationship, and the test mapping relationship; The step of determining the proportional coefficient according to the first functional relationship, the second functional relationship, and the test mapping relationship includes: Taking a plurality of lateral accelerations, corresponding to each of the lateral accelerations, using the steering torque gradient determined by the first functional relationship and the second functional relationship as a lower boundary value and an upper boundary value, respectively, and using the steering torque gradient determined by the test mapping relationship as a proportional coefficient input value; Dividing the difference between the proportional coefficient input value and the lower boundary by the difference between the upper boundary value and the lower boundary value to determine the initial proportional coefficient corresponding to the lateral acceleration; The initial proportional coefficients corresponding to the lateral accelerations are averaged and determined as the proportional coefficient.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the EPS power assist mode control method according to any one of claims 1 to 9 are implemented.

12. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions enable the computer to execute the steps of the EPS assist mode control method according to any one of claims 1 to 9.

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