Torque Compensation Method and Related Device for a By-Wire Steering System of a Vehicle

Abstract

The present disclosure relates to a torque compensation method and related device for a steer-by-wire system of a vehicle. The method includes: determining a required torque for steering feel of the steering system of the vehicle; obtaining vehicle speed information and steering wheel angle information of the vehicle, and obtaining a first output torque of a steering column in the steering system; determining a first required torque of a torque compensation motor from a preset torque compensation torque table according to the vehicle speed information and the steering wheel angle information; determining a compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque for steering feel, and compensating the first required torque according to the compensation torque to obtain a second required torque of the torque compensation motor; and controlling the torque compensation motor to output a torque for steering the steering system according to the second required torque. The present disclosure can not only improve the NVH performance, driving stability and safety of the vehicle, but also reduce the size of the feel simulation motor of the steer-by-wire column, and is more easily arranged in a vehicle with a small space.

Description

Technical Field

[0001] The present disclosure relates to the technical field of vehicle steer-by-wire systems, and in particular, to a torque compensation method and related device for a vehicle steer-by-wire system. Background Art

[0002] In vehicles, especially in transportation means, an electromechanical steering system or a steer-by-wire system is generally used to control vehicle steering. In the electromechanical steering system, a mechanical connection is formed between the steering wheel and the wheels, while the steer-by-wire system means that there is a wire control (electronic signal) connection between the driver input interface (steering wheel) and the actuator (steering wheel), and then by sending an electrical signal command to the assist motor, the steering system can be controlled to achieve information interaction.

[0003] In the steer-by-wire system, the parts inside the steering column will gradually wear after long-term use, resulting in a gradual increase in the internal part clearance, and the NVH performance of the steering system gradually deteriorates, which may cause abnormal noises and vibrations in the steering system, reducing the driving experience of the driver. At the same time, it will also cause the internal friction torque to gradually decrease, affecting control stability and safety. Especially during high-speed driving and when the feel simulation motor cannot output enough torque, due to the small friction torque, a slight turn of the steering wheel may cause the steering wheel to turn too large an angle, which is very likely to cause a car accident and reduce the safety performance of the vehicle. Summary of the Invention

[0004] To overcome the problems in the related art, the present disclosure provides a torque compensation method and related device for a vehicle steer-by-wire system.

[0005] According to a first aspect of the present disclosure, there is provided a torque compensation method for a vehicle steer-by-wire system, the method including:

[0006] Determine the required torque for the steering feel of the vehicle's steering system;

[0007] Obtain the vehicle speed information and the steering wheel angle information of the vehicle, and obtain the first output torque of the steering column in the steering system;

[0008] Determine the first required torque of the torque compensation motor from a preset torque compensation torque table according to the vehicle speed information and the steering wheel angle information;

[0009] Determine the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque for the steering feel, and compensate the first required torque according to the compensation torque to obtain the second required torque of the torque compensation motor;

[0010] Control the torque output by the torque compensation motor for steering the steering system according to the second required torque.

[0011] Optionally, the step of obtaining the first output torque of the steering column in the steering system includes:

[0012] Obtain the second output torque of the feel simulation motor in the steering system;

[0013] Obtain the first output torque of the steering column according to the second output torque, the reduction ratio of the first reduction mechanism corresponding to the feel simulation motor, and the transmission efficiency of the first reduction mechanism, where, in the case where the first reduction mechanism is not provided in the steering system, the transmission ratio of the first reduction mechanism is 1.

[0014] Optionally, the step of obtaining the first output torque of the steering column in the steering system includes:

[0015] Obtain the first output torque detected by the torque sensor provided in the steering column.

[0016] Optionally, the step of determining the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the steering feel required torque includes:

[0017] Obtain a third required torque according to the first required torque, the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and the transmission efficiency of the second reduction mechanism;

[0018] Determine the compensation torque of the torque compensation motor according to the first output torque, the third required torque, and the steering feel required torque.

[0019] Optionally, the step of determining the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the steering feel required torque includes:

[0020] Calculate the compensation torque ΔT according to the following formula:

[0021] ΔT = T0 - T1 - T2i2η2

[0022] where, T0 is the steering feel required torque, T1 is the first output torque, T2 is the first required torque, i2 is the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and η2 is the transmission efficiency of the second reduction mechanism.

[0023] Optionally, the step of determining the steering feel required torque of the steering system of the vehicle includes:

[0024] Obtain the rack force information of the steering system;

[0025] Calculate the required torque for the steering feel according to the vehicle speed information, the steering wheel angle information, and the rack force information.

[0026] Optionally, the torque compensation torque table includes multiple vehicle speed intervals, the multiple vehicle speed intervals include a first interval, a second interval, and a third interval, the upper limit value of the first interval is less than or equal to the lower limit value of the second interval, the upper limit value of the second interval is less than or equal to the lower limit value of the third interval, and within the first interval, the required torque of the torque compensation motor is negatively correlated with the vehicle speed, within the second interval, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to a first slope, within the third interval, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to a second slope, and the second slope is greater than the first slope.

[0027] Optionally, the torque compensation torque table includes multiple absolute value intervals of the steering angle, the multiple absolute value intervals of the steering angle include a fourth interval, a fifth interval, and a sixth interval, the upper limit value of the fourth interval is less than or equal to the lower limit value of the fifth interval, the upper limit value of the fifth interval is less than or equal to the lower limit value of the sixth interval, and within the fourth interval, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a third slope, within the fifth interval, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a fourth slope, within the sixth interval, the required torque of the torque compensation motor is positively correlated with the steering wheel angle, and the third slope is greater than the fourth slope.

[0028] According to a second aspect of the present disclosure, there is provided a torque compensation device for a steer-by-wire system of a vehicle, the device including:

[0029] A first determination module, configured to determine the required torque for the steering feel of the steering system of the vehicle;

[0030] An acquisition module, configured to acquire the vehicle speed information and the steering wheel angle information of the vehicle, and acquire the first output torque of the steering column in the steering system;

[0031] A second determination module, configured to determine the first required torque of the torque compensation motor from a preset torque compensation torque table according to the vehicle speed information and the steering wheel angle information;

[0032] A third determination module, configured to determine the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque for the steering feel, and compensate the first required torque according to the compensation torque to obtain the second required torque of the torque compensation motor;

[0033] A control module configured to control the torque output by the torque compensation motor for steering the steering system according to the second required torque.

[0034] According to a third aspect of the present disclosure, a steer-by-wire system for a vehicle is provided. The steer-by-wire system for a vehicle includes:

[0035] A steering wheel angle detection unit, a vehicle speed detection unit, a steering column torque measurement unit, a torque compensation motor, a feel simulation motor, and an electronic control unit;

[0036] The steering wheel angle detection unit, the vehicle speed detection unit, the torque compensation motor, the feel simulation motor, and the steering column torque measurement unit are all communicatively connected to the electronic control unit. The torque compensation motor and the feel simulation motor are mounted on the steering column;

[0037] The steering wheel angle detection unit is configured to detect steering wheel angle information and send it to the electronic control unit;

[0038] The vehicle speed detection unit is configured to detect vehicle speed information and send it to the electronic control unit;

[0039] The steering column torque measurement unit is configured to detect a first output torque of the steering column and send it to the electronic control unit;

[0040] The electronic control unit is configured to receive the vehicle speed information, the steering wheel angle information, and the first output torque, and execute the method according to the first aspect of the present disclosure to control the torque output by the torque compensation motor for steering the steering system.

[0041] According to a fourth aspect of the present disclosure, a vehicle is provided, which employs the steer-by-wire system according to the third aspect of the present disclosure.

[0042] In an embodiment of the present disclosure, according to vehicle speed information and steering wheel angle information, a first required torque of a torque compensation motor is determined from a preset torque compensation torque table, so as to determine the torque that the torque compensation motor originally needs to output under different driving conditions of the vehicle. According to the first required torque, the required torque for the steering feel of the steering system, and the first output torque of the steering column in the steering system, the compensation torque of the torque compensation motor is determined. A second required torque obtained by compensating the first required torque according to the compensation torque is used to control the torque compensation motor to output the torque for steering the steering system. During this process, in the second required torque output by the torque compensation motor, the situation of reduced frictional torque caused by wear between internal parts of the steering column is considered. The pressing force state between the internal parts of the steering column can be increased by the compensation torque output by the torque compensation motor, so that the frictional torque between the internal parts of the steering column increases, and the abnormal noise and vibration phenomena caused by insufficient frictional torque can be reduced, thereby improving the NVH performance of the steering system. The problem of the current decline in the NVH performance of the steering system and the reduction of the driving experience can be effectively solved. Moreover, during high-speed driving and when the feel simulation motor cannot output sufficient torque, due to the small frictional torque, a slight turn of the steering wheel may cause the steering wheel to turn by too large an angle, which is very likely to cause a car accident and reduce the safety performance of the vehicle. By increasing the internal frictional torque of the vehicle steering column in the present disclosure, the control stability and safety of the vehicle can also be improved.

[0043] In addition, by setting the torque compensation motor, a smaller-sized feel simulation motor can be selected to provide a sufficiently large required torque for the steering feel, reducing the overall size and cost of the steer-by-wire steering column and making it easier to arrange in a vehicle with a small space.

[0044] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present disclosure and used together with the specification to explain the principles of the present disclosure.

[0046] Figure 1 is a schematic structural diagram of a vehicle steer-by-wire steering system shown according to an exemplary embodiment.

[0047] Figure 2 is a flowchart of a torque compensation method for a vehicle steer-by-wire steering system shown according to an exemplary embodiment.

[0048] Figure 3 is a schematic diagram showing the variation of the required torque with vehicle speed in a preset torque compensation torque table of a torque compensation method for a vehicle steer-by-wire steering system shown according to an exemplary embodiment.

[0049] Figure 4 It is a schematic diagram showing the variation of the required torque with the absolute value of the steering angle in a preset torque compensation torque table of a torque compensation method for a steer-by-wire system of a vehicle shown according to an exemplary embodiment.

[0050] Figure 5 It is a block diagram of the structure of a torque compensation device for a steer-by-wire system of a vehicle shown according to an exemplary embodiment.

[0051] Figure 6 It is a schematic diagram of the structure of a steer-by-wire system of a vehicle shown according to another exemplary embodiment.

[0052] Figure 7 It is a schematic diagram of a functional block diagram of a vehicle shown according to an exemplary embodiment.

[0053] Figure 8 It is a block diagram of a device for implementing a torque compensation method for a steer-by-wire system of a vehicle shown according to an exemplary embodiment. Detailed implementation manners

[0054] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all the implementation manners consistent with the present disclosure. On the contrary, they are only examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0055] Electrification, intelligence, and technology are the development trends of automobiles. Each automobile enterprise is involved in the development and upgrade of steer-by-wire system technology, and more and more vehicles equipped with steer-by-wire systems will be successively launched into the market.

[0056] In the related art, the parts inside the steering column gradually wear out with long-term use, and the gap between the parts gradually increases, which may cause abnormal noises and vibrations during vehicle driving, reducing the NVH performance of the steering system and the driving experience of the driver. The present disclosure can compensate for the output torque of the steering column by controlling the torque compensation motor, thereby improving the NVH performance of the steering system and enhancing the driving experience of the driver. Moreover, during high-speed driving, when the feel simulation motor cannot output sufficient torque, due to the small frictional torque, a slight turn of the steering wheel may cause the steering wheel to turn through too large an angle, which is very likely to lead to a car accident and reduce the safety performance of the vehicle. By increasing the internal frictional torque of the column through the present disclosure, the control stability and safety of the vehicle can also be improved. In addition, by adding a torque compensation motor unit, a smaller-sized feel simulation motor can be selected to provide a sufficient torque requirement for the steering feel, reducing the overall size and cost of the steer-by-wire column and making it easier to be arranged in a vehicle with a small space.

[0057] Specifically, the mechanical structure of the steering system involved in the present disclosure is as Figure 1 shown. The steering system includes a steering wheel 10, a steering column 20, a feel simulation motor 40, a torque compensation motor 60, and a second reduction mechanism 50. Among them, the steering wheel 10 is connected to the steering column 20, and the steering column 20 is connected to the feel simulation motor 40 through a first reduction mechanism 30; the torque compensation motor 60 is arranged on the steering column 20 through the second reduction mechanism 50, and the second reduction mechanism 50 converts the output torque of the torque compensation motor 60 at a certain ratio; the torque output after the conversion of the torque compensation motor 60 by the second reduction mechanism 50 can change the pressing force state between the internal parts of the steering column 20, and then the frictional torque between the internal parts of the steering column 20 changes. In another embodiment, the steering column 20 is directly connected to the feel simulation motor 40, and the first reduction mechanism 30 is not provided.

[0058] Figure 2 is a flowchart of a torque compensation method for a vehicle steer-by-wire system shown according to an exemplary embodiment. As Figure 2 shown, the method includes the following steps.

[0059] In step S11, determine the torque requirement for the steering feel of the vehicle's steering system.

[0060] Exemplarily, the torque requirement for the steering feel is the torque magnitude required to turn the steering wheel when the driver controls the steering wheel to turn to steer the vehicle's steering wheel. The torque requirement for the steering feel can be obtained by calculating based on the vehicle speed information, the steering wheel angle information, and the rack force information.

[0061] In step S12, obtain the vehicle speed information and the steering wheel angle information, and obtain the first output torque of the steering column in the steering system.

[0062] Exemplarily, the vehicle speed information includes the current vehicle speed of the vehicle, which can be obtained according to the vehicle speed sensor provided on the wheel. The steering wheel angle information may include the angle by which the steering wheel rotates from the zero-degree position to the current position, which can be obtained according to the steering wheel angle sensor, and may also include the torque magnitude when the steering wheel rotates this angle, which can be obtained according to the steering wheel torque sensor. The first output torque of the steering column is a torque parameter inside the steering column and serves as a variable parameter in the torque compensation algorithm described in the present invention. The value of the first output torque can be obtained according to the torque output by the feel simulation motor, or can be the measured torque value of the torsion bar sensor inside the steering column.

[0063] In step S13, according to the vehicle speed information and the steering wheel angle information, determine the first required torque of the torque compensation motor from the preset torque compensation torque table.

[0064] Exemplarily, the first required torque is the torque originally output by the torque compensation motor obtained according to the vehicle speed information and the steering wheel angle information without considering the wear of the internal parts of the steering column. The torque compensation torque table is a three-dimensional table, and the first required torque of the torque compensation motor can be determined from the torque compensation torque table according to the vehicle speed information and the steering wheel angle information.

[0065] Specifically, the data in the preset torque compensation torque table are calibration values obtained in advance according to the tests of the vehicle, that is, the torque magnitudes output by the torque compensation motor of the vehicle without considering the wear of the internal parts of the steering column and under different vehicle speeds and different steering wheel angles. The data in the preset torque compensation torque table can also have corresponding change trends according to the change trends of different vehicle speed intervals and the change trends of different absolute value intervals of the steering wheel angle. The first required torque obtained according to the vehicle speed information and the steering wheel angle information takes into account the steering feel torque requirements of the vehicle under different working conditions.

[0066] In step S14, according to the first output torque, the first required torque, and the steering feel required torque, determine the compensation torque of the torque compensation motor, and compensate the first required torque according to the compensation torque to obtain the second required torque of the torque compensation motor.

[0067] Exemplarily, the compensation torque is the torque that the torque compensation motor needs to incrementally output for the steering feel required torque considering the wear of the internal parts of the steering column. The second required torque is obtained by summing the first required torque originally output by the torque compensation motor without considering the wear of the internal parts of the steering column and the compensation torque.

[0068] In step S15, control the torque compensation motor to output the torque for steering the steering system according to the second required torque.

[0069] Exemplarily, after obtaining the second required torque, the torque compensation motor can be controlled to output the second required torque.

[0070] In the embodiments of the present disclosure, according to the vehicle speed information and the steering wheel angle information, the first required torque of the torque compensation motor is determined from a preset torque compensation torque table, and the torque that the torque compensation motor originally needs to output under different driving conditions of the vehicle can be determined. According to the first required torque, the steering feel required torque of the steering system, and the first output torque of the steering column in the steering system, the compensation torque of the torque compensation motor is determined. The second required torque obtained by compensating the first required torque according to the compensation torque is used to control the torque compensation motor to output the torque for steering the steering system. During this process, in the second required torque output by the torque compensation motor, the situation of the reduction of the frictional torque caused by the wear between the internal parts of the steering column is considered. The pressing force state between the internal parts of the steering column can be increased by the compensation torque output by the torque compensation motor, so that the frictional torque between the internal parts of the steering column increases, and the abnormal noise and vibration phenomena caused by insufficient frictional torque can be reduced, improving the NVH performance of the steering system. The problem of the current decline in the NVH performance of the steering system and the reduction of the driving experience can be effectively solved.

[0071] In addition, in the case where the actual first output torque output by the feel simulation motor fails or malfunctions and is small or zero, the torque compensation motor can provide the steering feel required torque required by the steering system. In this way, when the driver controls the steering wheel, the steering column will not rotate due to a small hand force or interference force, thus avoiding the current safety anxiety brought to the driver by the failure of the feel simulation motor, as well as the driving stability and safety problems during high-speed driving.

[0072] In one embodiment, when the steering feel required torque of the steering system of the vehicle is constant, after providing a part of the frictional torque by the torque compensation motor, a smaller specification of the feel simulation motor can be selected, and a sufficiently large steering feel required torque can be provided, thereby reducing the cost and the overall size of the steering column, and being more easily arranged in a vehicle space with a smaller radial dimension space.

[0073] In some embodiments, the step of obtaining the first output torque of the steering column in the steering system includes:

[0074] Obtaining the second output torque of the feel simulation motor in the steering system;

[0075] According to the second output torque, the reduction ratio of the first reduction mechanism corresponding to the feel simulation motor, and the transmission efficiency of the first reduction mechanism, the first output torque of the steering column is obtained, wherein, in the case where the first reduction mechanism is not provided in the steering system, the transmission ratio of the first reduction mechanism is 1.

[0076] Exemplarily, the first output torque of the steering column is obtained based on the second output torque of the feel simulation motor. When the first reduction mechanism is not provided in the steering system, the transmission ratio of the first reduction mechanism is 1. That is, when the first reduction mechanism is not provided, the second output torque of the feel simulation motor can be used as the first output torque of the steering column. When the first reduction mechanism is provided in the steering system, the first output torque of the steering column is obtained based on the product of the second output torque of the feel simulation motor, the reduction ratio of the first reduction mechanism, and the transmission efficiency.

[0077] In some other embodiments, the step of obtaining the first output torque of the steering column in the steering system includes:

[0078] Obtaining the first output torque detected by the torque sensor provided in the steering column.

[0079] Exemplarily, the first output torque of the steering column can also be obtained based on the torque sensor. The torque sensor is provided in the steering column and can detect the torque value on the torsion bar located in the steering column, and this torque value is the first output torque.

[0080] In some embodiments, the step of determining the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the steering feel required torque includes:

[0081] Obtaining a third required torque according to the first required torque, the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and the transmission efficiency of the second reduction mechanism;

[0082] Determining the compensation torque of the torque compensation motor according to the first output torque, the third required torque, and the steering feel required torque.

[0083] Exemplarily, when the torque compensation motor is correspondingly provided with a second reduction mechanism, the third required torque can be obtained according to the product of the first required torque, the reduction ratio of the second reduction mechanism, and the transmission efficiency of the second reduction mechanism. The difference obtained by subtracting the first output torque and the third required torque from the steering feel required torque in sequence can be used to obtain the compensation torque of the torque compensation motor.

[0084] In one implementation manner, the step of determining the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the steering feel required torque includes:

[0085] Calculating the compensation torque ΔT according to the following formula:

[0086] ΔT = T0 - T1 - T2i2η2

[0087] Among them, T0 is the required torque for steering feel, T1 is the first output torque, T2 is the first required torque, i2 is the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and η2 is the transmission efficiency of the second reduction mechanism.

[0088] In another embodiment, when the first output torque is obtained from the feel simulation motor in the steering system, T1 = T3i1η1, where T3 is the second output torque of the feel simulation motor, i1 is the reduction ratio of the first reduction mechanism corresponding to the feel simulation motor, and η1 is the transmission efficiency of the first reduction mechanism. When the first output torque is detected by the torque sensor provided in the steering column, the measured torque value detected by the torque sensor can be directly used as the value of the first output torque.

[0089] In some embodiments, the steps of determining the required torque for steering feel of the vehicle's steering system include:

[0090] Obtain the rack force information of the steering system;

[0091] Calculate the required torque for steering feel based on the vehicle speed information, steering wheel angle information, and rack force information.

[0092] Specifically, the rack force information is the force received on the rack. The value of the rack force can be determined and estimated according to the received information and the set information through the model formula of the preset model for estimating the rack force. There are various preset models for estimating the rack force in the related art of this field, and the present disclosure does not limit them here.

[0093] According to the driver's operation of the steering wheel, based on the vehicle speed information and steering wheel angle information of the vehicle at the current moment, the rack force information can be converted into the required torque for steering feel of the steering system by using the preset model for estimating the rack force.

[0094] In one embodiment, the preset torque compensation torque table is essentially a three-dimensional table in which the required torque value varies with the vehicle speed and the steering wheel angle. By inputting the vehicle speed value and the steering wheel angle at the current moment, the first required torque of the torque compensation motor can be output.

[0095] Specifically, the torque compensation torque table includes multiple vehicle speed intervals, and the multiple vehicle speed intervals include a first interval, a second interval, and a third interval. The upper limit value of the first interval is less than or equal to the lower limit value of the second interval, and the upper limit value of the second interval is less than or equal to the lower limit value of the third interval. And within the first interval, the required torque of the torque compensation motor is negatively correlated with the vehicle speed. Within the second interval, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to the first slope. Within the third interval, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to the second slope, and the second slope is greater than the first slope.

[0096] Exemplarily, in a preset torque compensation torque table, the three-dimensional table is projected onto a two-dimensional graph related to the vehicle speed, obtaining a schematic diagram of the required torque varying with the vehicle speed as shown in Figure 3 The schematic diagram shows that the compensation torque value of the torque compensation torque table varies with the vehicle speed. When the vehicle speed is 0, the value is the largest; when the vehicle speed reaches a certain critical vehicle speed, the value reaches the smallest; then as the vehicle speed increases, the value becomes larger and larger.

[0097] Figure 3 Shown is one example of the overall trend case. The trend of this curve and the setting of the specific values can be changed according to the requirements of the actual vehicle.

[0098] Exemplarily, when the vehicle speed is 0, the vehicle is not moving, that is, the vehicle is steering in place. The first required torque output by the hand feeling simulation motor is the largest, which can simulate the characteristic that the driver's hand force is relatively heavy when steering in place in a traditional steering system (non-by-wire steering system).

[0099] Exemplarily, within the first interval of the vehicle speed range, the vehicle speed is greater than 0 and less than or equal to the first threshold. At this time, when simulating the vehicle in a traditional steering system during a stable low-speed driving process, the characteristic that the driver does not need a large steering force to control the steering wheel rotation when controlling the vehicle to turn is considered. Then, the output torque of the torque compensation motor is reduced, that is, the frictional torque provided by the torque compensation motor is reduced, making it easier for the driver to operate the steering wheel.

[0100] Exemplarily, within the second interval of the vehicle speed range, the vehicle speed is greater than the first threshold and less than or equal to the second threshold. As the vehicle speed increases, to ensure the safety of vehicle driving, within the second interval, the required torque value output by the torque compensation motor gradually increases with the increase of the vehicle speed, and the increase amplitude is small.

[0101] Exemplarily, within the third interval of the vehicle speed range, the vehicle speed is greater than the second threshold. When the vehicle is driving at a high speed, to avoid the danger that even a slight operation or misoperation of the steering wheel can cause a large angular rotation of the steering wheel due to the lightness of the steering wheel, in the high-speed driving state, by increasing the frictional torque provided by the torque compensation motor, the driver needs to use more force to turn the steering wheel to ensure driving safety. That is, within the third interval, the required torque value output by the torque compensation motor gradually increases with the increase of the vehicle speed, and the increase amplitude is large.

[0102] In addition, within the first interval, the required torque of the torque compensation motor and the vehicle speed are negatively correlated according to the fifth slope, and the absolute value of the fifth slope is greater than the second slope.

[0103] It can be understood that the second threshold is greater than the first threshold, the first threshold is greater than 0, and the first threshold and the second threshold can be determined according to the results of vehicle performance tests or prior knowledge.

[0104] In some embodiments, the torque compensation torque table includes a plurality of absolute steering angle intervals. The plurality of absolute steering angle intervals include a fourth interval, a fifth interval, and a sixth interval. The upper limit value of the fourth interval is less than or equal to the lower limit value of the fifth interval, and the upper limit value of the fifth interval is less than or equal to the lower limit value of the sixth interval. In the fourth interval, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a third slope. In the fifth interval, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a fourth slope. In the sixth interval, the required torque of the torque compensation motor is positively correlated with the steering wheel angle, and the third slope is greater than the fourth slope.

[0105] Exemplarily, referring to Figure 4 , in the preset torque compensation torque table, project the three-dimensional table onto a two-dimensional graph related to the absolute value of the steering wheel angle, and obtain a schematic diagram of the required torque varying with the absolute value of the angle as shown in Figure 4 . Among them, the compensation torque value of the torque compensation torque table varies with the angle. When the angle is 0, the value is the largest; when the angle reaches a certain critical vehicle speed, the angle reaches the minimum; then as the angle increases, the value becomes larger and larger. Based on the middle position of the steering wheel, the compensation torque values corresponding to the positive angle of turning to the right and the negative angle of turning to the left are symmetric.

[0106] Figure 4 Shown is a schematic diagram of one overall trend case. The trend of this curve and the setting of specific values can be changed according to the actual vehicle requirements.

[0107] Exemplarily, in the fourth interval of the absolute steering angle interval, the steering wheel angle is greater than zero and less than a third threshold value, and the absolute value of the steering wheel angle is relatively small. Set the required torque within a relatively large range, so that the driver uses a relatively large steering force to control the steering wheel to ensure the steering stability near the middle position of the steering wheel. In particular, it can prevent dangerous situations from occurring when the vehicle is driving at high speed and a slight operation or misoperation of the steering wheel can cause a large angular rotation of the steering wheel. And in the fourth interval, as the absolute value of the steering wheel angle increases, the required torque output by the torque compensation motor decreases, and the degree of decrease is relatively large. Make the driver's steering operation gradually lighter.

[0108] Exemplarily, in the fifth interval of the absolute steering angle interval, the steering wheel angle is greater than or equal to the third threshold value and less than the fourth threshold value. In order to make the driver's steering operation lighter, in the fifth interval, as the absolute value of the steering wheel angle increases, the required torque output by the torque compensation motor decreases, and the degree of decrease is relatively small.

[0109] Exemplarily, within the sixth interval of the absolute value range of the steering wheel angle, the steering wheel angle is greater than or equal to the fourth threshold and less than the fifth threshold, and the absolute value of the steering wheel angle is relatively large. By setting the required torque within a relatively large range, the driver needs to apply a relatively large steering force to control the steering wheel, which can avoid dangerous situations caused by the driver oversteering the steering wheel. Within the sixth interval, as the absolute value of the steering wheel angle increases, the required torque output by the torque compensation motor increases.

[0110] In addition, within the sixth interval of the steering, the required torque of the torque compensation motor and the steering wheel angle are positively correlated according to the sixth slope, and the absolute value of the third slope is greater than the sixth slope.

[0111] It can be understood that the fifth threshold is greater than the fourth threshold, the fourth threshold is greater than the third threshold, and the third threshold is greater than zero.

[0112] Figure 5 is a block diagram of a torque compensation device 100 of a steer-by-wire system of a vehicle shown according to an exemplary embodiment. Refer to Figure 5 The torque compensation device of the steer-by-wire system of the vehicle includes a first determination module 121, an acquisition module 122, a second determination module 123, a third determination module 124, and a control module 125.

[0113] The first determination module 121 is configured to determine the required torque of the steering feel of the steering system of the vehicle;

[0114] The acquisition module 122 is configured to acquire the vehicle speed information and the steering wheel angle information of the vehicle, and acquire the first output torque of the steering column in the steering system;

[0115] The second determination module 123 is configured to determine the first required torque of the torque compensation motor from a preset torque compensation torque table according to the vehicle speed information and the steering wheel angle information;

[0116] The third determination module 124 is configured to determine the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque of the steering feel, and compensate the first required torque according to the compensation torque to obtain the second required torque of the torque compensation motor;

[0117] The control module 125 is configured to control the torque compensation motor to output the torque for steering the steering system according to the second required torque.

[0118] In some embodiments, the acquisition module 122 is further configured to:

[0119] acquire the second output torque of the feel simulation motor in the steering system;

[0120] Obtain the first output torque of the steering column according to the second output torque, the reduction ratio of the first reduction mechanism corresponding to the feel simulation motor, and the transmission efficiency of the first reduction mechanism. Wherein, when the first reduction mechanism is not provided in the steering system, the transmission ratio of the first reduction mechanism is 1.

[0121] In some embodiments, the obtaining module 122 is further configured to:

[0122] Obtain the first output torque detected by a torque sensor disposed within the steering column.

[0123] In some embodiments, the third determination module 124 is further configured to:

[0124] Obtain a third required torque according to the first required torque, the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and the transmission efficiency of the second reduction mechanism;

[0125] Determine the compensation torque of the torque compensation motor according to the first output torque, the third required torque, and the steering feel required torque.

[0126] In some embodiments, the third determination module 124 is further configured to:

[0127] Calculate the compensation torque ΔT according to the following formula:

[0128] ΔT = T0 - T1 - T2i2η2

[0129] Wherein, T0 is the steering feel required torque, T1 is the first output torque, T2 is the first required torque, i2 is the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and η2 is the transmission efficiency of the second reduction mechanism.

[0130] In some embodiments, the first determination module 121 is further configured to:

[0131] Obtain the rack force information of the steering system;

[0132] Calculate the steering feel required torque according to the vehicle speed information, the steering wheel angle information, and the rack force information.

[0133] In some embodiments, the torque compensation torque table of the second determination module 123 includes multiple vehicle speed intervals. The multiple vehicle speed intervals include a first interval, a second interval, and a third interval. The upper limit value of the first interval is less than or equal to the lower limit value of the second interval, and the upper limit value of the second interval is less than or equal to the lower limit value of the third interval. And within the first interval, the required torque of the torque compensation motor is negatively correlated with the vehicle speed. Within the second interval, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to a first slope. Within the third interval, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to a second slope, and the second slope is greater than the first slope.

[0134] In some embodiments, the torque compensation torque table of the second determination module 123 includes a plurality of absolute steering angle intervals, the plurality of absolute steering angle intervals including a fourth interval, a fifth interval, and a sixth interval. The upper limit value of the fourth interval is less than or equal to the lower limit value of the fifth interval, the upper limit value of the fifth interval is less than or equal to the lower limit value of the sixth interval, and within the fourth interval, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a third slope. Within the fifth interval, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a fourth slope. Within the sixth interval, the required torque of the torque compensation motor is positively correlated with the steering wheel angle, and the third slope is greater than the fourth slope.

[0135] Regarding the torque compensation device 100 of the vehicle by - wire steering system in the above - mentioned embodiments, the specific manners in which each module performs operations have been described in detail in the embodiments of the torque compensation method for the vehicle by - wire steering system, and will not be elaborated here.

[0136] The present disclosure also provides a computer - readable storage medium, on which computer program instructions are stored. When the program instructions are executed by a processor, the torque compensation method for the vehicle by - wire steering system provided by the present disclosure is implemented.

[0137] Figure 6 is a schematic structural diagram of a vehicle by - wire steering system shown according to another exemplary embodiment. Referring to Figure 6 , the vehicle by - wire steering system includes:

[0138] a steering wheel angle detection unit, a vehicle speed detection unit, a steering column torque measurement unit, a torque compensation motor, a feel simulation motor, and an electronic control unit;

[0139] The steering wheel angle detection unit, the vehicle speed detection unit, the torque compensation motor, the feel simulation motor, and the steering column torque measurement unit are all communicatively connected to the electronic control unit. The torque compensation motor and the feel simulation motor are installed on the steering column;

[0140] The steering wheel angle detection unit is configured to detect steering wheel angle information and send it to the electronic control unit;

[0141] The vehicle speed detection unit is configured to detect vehicle speed information and send it to the electronic control unit;

[0142] The steering column torque measurement unit is configured to detect the first output torque of the steering column and send it to the electronic control unit;

[0143] The electronic control unit is configured to receive vehicle speed information, steering wheel angle information, and a first output torque, and execute the torque compensation method of the above vehicle-by-wire steering system to control the torque output by the torque compensation motor for steering the steering system.

[0144] Wherein, the electronic control unit may include at least one first processor and a first memory, and the first processor may execute instructions stored in the first memory.

[0145] The first processor may be any conventional processor, such as a commercially available CPU. The first processor may also include, for example, a Graphic Process Unit (GPU), a Field Programmable Gate Array (FPGA), a System on Chip (SOC), an Application Specific Integrated Circuit (ASIC), or a combination thereof.

[0146] The first memory may be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic memory, flash memory, a magnetic disk, or an optical disk.

[0147] In an embodiment of the present disclosure, the first processor may execute instructions to complete all or part of the steps of the above torque compensation method of the vehicle-by-wire steering system.

[0148] The present disclosure further provides a vehicle, which includes the above vehicle-by-wire steering system.

[0149] In some embodiments, the vehicle 600 may be a hybrid vehicle, an electric vehicle, or other types of vehicles. The vehicle 600 may be an autonomous vehicle or a semi-autonomous vehicle.

[0150] Refer to Figure 7 , Figure 7 is a block diagram of a vehicle 600 shown according to an exemplary embodiment. The vehicle 600 may include various subsystems. For example, an infotainment system 610, a perception system 620, a decision control system 630, a drive system 640, and the vehicle-by-wire steering system as described above. Among them, the vehicle 600 may further include more or fewer subsystems, and each subsystem may include multiple components. In addition, each subsystem and each component of the vehicle 600 may be interconnected by wired or wireless means.

[0151] In some embodiments, the infotainment system 610 may include a communication system, an entertainment system, a navigation system, and the like.

[0152] The perception system 620 may include several sensors for sensing information about the environment around the vehicle 600. For example, the perception system 620 may include a global positioning system (the global positioning system may be a GPS system, a Beidou system, or other positioning systems), an inertial measurement unit (IMU), lidar, millimeter-wave radar, ultrasonic radar, and a camera device.

[0153] The decision control system 630 may include a computing system, a vehicle controller, a steering system, an accelerator, and a braking system.

[0154] The drive system 640 may include components that provide motive power for the vehicle 600. In one embodiment, the drive system 640 may include an engine, an energy source, a powertrain, and wheels. The engine may be one or a combination of an internal combustion engine, an electric motor, and an air compression engine. The engine can convert the energy provided by the energy source into mechanical energy.

[0155] Figure 8 is a block diagram of a device 1900 for implementing a torque compensation method of a steer-by-wire system of a vehicle according to an exemplary embodiment. For example, the device 1900 may be provided as a server. Referring to Figure 8 , the device 1900 includes a processing component 1922, which further includes one or more second processors, and memory resources represented by a second memory 1932 for storing instructions executable by the processing component 1922, such as application programs. The application programs stored in the second memory 1932 may include one or more modules each corresponding to a set of instructions. In addition, the processing component 1922 is configured to execute instructions to perform the above-mentioned torque compensation method of the steer-by-wire system of the vehicle.

[0156] The device 1900 may further include a power supply component 1926 configured to perform power management of the device 1900, a wired or wireless network interface 1950 configured to connect the device 1900 to a network, and an input / output interface 1958. The device 1900 may operate based on an operating system stored in the second memory 1932, such as Windows Server TM , Mac OSX TM , Unix TM , Linux TM , FreeBSD TM or the like.

[0157] In another exemplary embodiment, a computer program product is also provided. The computer program product includes a computer program that can be executed by a programmable device, and the computer program has a code portion for performing the torque compensation method of the above-described steer-by-wire system of a vehicle when executed by the programmable device.

[0158] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the present disclosure. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common knowledge or conventional technical means in the technical field not disclosed by the present disclosure. The specification and embodiments are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the following claims.

[0159] It should be understood that the present disclosure is not limited to the exact structures already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. A torque compensation method for a steer-by-wire system of a vehicle, characterized in that, The method includes: Determining the required torque for the steering feel of the vehicle's steering system; Obtaining the vehicle speed information and the steering wheel angle information of the vehicle, and obtaining the first output torque of the steering column in the steering system; Determining the first required torque of the torque compensation motor from a preset torque compensation torque table according to the vehicle speed information and the steering wheel angle information; Determining the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque for the steering feel, and compensating the first required torque according to the compensation torque to obtain the second required torque of the torque compensation motor; Controlling the torque compensation motor to output the torque for steering the steering system according to the second required torque; The step of determining the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque for the steering feel includes: Calculating the compensation torque ΔT according to the following formula: ΔT = T0 - T1 - T2i2η2 Wherein, T0 is the required torque for the steering feel, T1 is the first output torque, T2 is the first required torque, i2 is the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and η2 is the transmission efficiency of the second reduction mechanism; The step of determining the required torque for the steering feel of the vehicle's steering system includes: Obtaining the rack force information of the steering system; Calculating the required torque for the steering feel according to the vehicle speed information, the steering wheel angle information, and the rack force information.

2. The method according to claim 1, wherein The step of obtaining the first output torque of the steering column in the steering system includes: Obtaining the second output torque of the feel simulation motor in the steering system; Obtaining the first output torque of the steering column according to the second output torque, the reduction ratio of the first reduction mechanism corresponding to the feel simulation motor, and the transmission efficiency of the first reduction mechanism, wherein when the first reduction mechanism is not provided in the steering system, the transmission ratio of the first reduction mechanism is 1.

3. The method according to claim 1, wherein The step of obtaining the first output torque of the steering column in the steering system includes: Obtaining the first output torque detected by a torque sensor provided in the steering column.

4. The method according to claim 1, characterized in that, The step of determining the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque for the steering feel includes: Obtaining a third required torque according to the first required torque, the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and the transmission efficiency of the second reduction mechanism; Determining the compensation torque of the torque compensation motor according to the first output torque, the third required torque, and the required torque for the steering feel.

5. The method according to any one of claims 1 to 4, characterized in that, The torque compensation torque table includes multiple vehicle speed ranges, the multiple vehicle speed ranges including a first range, a second range, and a third range. The upper limit value of the first range is less than or equal to the lower limit value of the second range, and the upper limit value of the second range is less than or equal to the lower limit value of the third range. And within the first range, the required torque of the torque compensation motor is negatively correlated with the vehicle speed. Within the second range, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to a first slope. Within the third range, the required torque of the torque compensation motor is positively correlated with the vehicle speed according to a second slope, and the second slope is greater than the first slope.

6. The method according to any one of claims 1-4, characterized in that, The torque compensation torque table includes multiple absolute steering angle ranges, the multiple absolute steering angle ranges including a fourth range, a fifth range, and a sixth range. The upper limit value of the fourth range is less than or equal to the lower limit value of the fifth range, and the upper limit value of the fifth range is less than or equal to the lower limit value of the sixth range. And within the fourth range, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a third slope. Within the fifth range, the required torque of the torque compensation motor is negatively correlated with the absolute value of the steering wheel angle according to a fourth slope. Within the sixth range, the required torque of the torque compensation motor is positively correlated with the steering wheel angle, and the third slope is greater than the fourth slope.

7. A torque compensation device for a steer-by-wire system of a vehicle, characterized in that, The device includes: A first determination module configured to determine the required torque for the steering feel of the vehicle's steering system; An acquisition module configured to acquire the vehicle speed information and the steering wheel angle information of the vehicle, and acquire the first output torque of the steering column in the steering system; A second determination module configured to determine the first required torque of the torque compensation motor from a preset torque compensation torque table according to the vehicle speed information and the steering wheel angle information; A third determination module configured to determine the compensation torque of the torque compensation motor according to the first output torque, the first required torque, and the required torque for the steering feel, and compensate the first required torque according to the compensation torque to obtain the second required torque of the torque compensation motor; A control module configured to control the torque compensation motor to output the torque for steering the steering system according to the second required torque; The third determination module is further configured to: Calculate the compensation torque ΔT according to the following formula: ΔT = T0 - T1 - T2i2η2 where T0 is the required torque for the steering feel, T1 is the first output torque, T2 is the first required torque, i2 is the reduction ratio of the second reduction mechanism corresponding to the torque compensation motor, and η2 is the transmission efficiency of the second reduction mechanism; The first determination module is further configured to: Acquire the rack force information of the steering system; Calculate the required torque for the steering feel according to the vehicle speed information, the steering wheel angle information, and the rack force information.

8. A steer-by-wire system for a vehicle, characterized in that, The steer-by-wire system of the vehicle includes: A steering wheel angle detection unit, a vehicle speed detection unit, a steering column torque measurement unit, a torque compensation motor, a feel simulation motor, and an electronic control unit; The steering wheel angle detection unit, the vehicle speed detection unit, the torque compensation motor, the haptic simulation motor, and the steering column torque measurement unit are all communicatively connected to the electronic control unit. The torque compensation motor and the haptic simulation motor are mounted on the steering column; The steering wheel angle detection unit is configured to detect steering wheel angle information and send it to the electronic control unit; The vehicle speed detection unit is configured to detect vehicle speed information and send it to the electronic control unit; The steering column torque measurement unit is configured to detect the first output torque of the steering column and send it to the electronic control unit; The electronic control unit is configured to receive the vehicle speed information, the steering wheel angle information, and the first output torque, and execute the method according to any one of claims 1-6 to control the torque output by the torque compensation motor for steering the steering system.

9. A vehicle, characterized in that, A steer-by-wire system as described in claim 8 is adopted.

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