Indirect steering wheel angle control system and method, storage medium and computer program product

Abstract

The invention discloses an indirect steering wheel angle control system and method, a storage medium and a computer program product. On the premise that a steering wheel rotation angle sensor of the vehicle is omitted, accurate and reliable steering wheel rotation angle signals are output through calculation of the position of the power-assisted motor by the EPS and the ESC and mutual verification compensation of output steering wheel rotation angles, and the requirements of various functions of the vehicle for the steering wheel rotation angle signals are met; and the purpose of reducing the cost is achieved by canceling physical parts.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle control, and in particular relates to an indirect steering wheel angle control system, method, storage medium and computer program product. Background Art

[0002] With the development of the automobile industry, the rise of new energy vehicles and smart cars, the competition among OEMs is becoming increasingly fierce. In order to enhance brand competitiveness, OEMs are increasing product attractiveness by continuously adding advanced functions such as assisted driving and automatic driving, while increasing corporate profit margins through cost-cutting designs.

[0003] As a core component that meets the steering needs of the vehicle during driving, the steering system must not only meet the increasingly mature requirements of various ADAS intelligent driving functions, but also meet the driver's requirements for handling stability and driving comfort. A stable, reliable and accurate steering wheel angle signal is the basic condition for achieving excellent vehicle steering performance, ESC vehicle stability control and various ADAS intelligent driving functions.

[0004] Vehicles currently on the market use steering wheel angle sensors to provide the required vehicle angle signals to achieve steering, ESC vehicle stability control, and ADAS intelligent driving functions. The steering wheel angle sensors of existing models on the market are usually modularly defined parts inherent to suppliers. When designing and developing vehicles, the OEM needs to reserve assembly interfaces and perform software signal matching based on the part's appearance structure and signal definition, which adds a certain degree of difficulty to design and development. Summary of the invention

[0005] In order to enable a vehicle to obtain an accurate and reliable steering wheel angle signal without a steering wheel angle sensor, the present invention provides an indirect steering wheel angle control system, method, storage medium and computer program product.

[0006] An indirect steering wheel angle control system for achieving one of the purposes of the present invention, an indirect steering wheel angle control system, comprising:

[0007] Initial calibration module: used to calibrate the steering rack travel of the vehicle to obtain the total rack travel and the first motor angle at the time of leaving the factory; the calibration method includes:

[0008] The steering wheel is rotated from one extreme position to the other extreme position and the total rack travel of the motor at the factory during this period is recorded, and the motor angle corresponding to the midpoint of the total rack travel at the factory is calibrated as the first motor angle;

[0009] Steering wheel 0° position calibration module: used to calibrate the 0° position of the steering wheel; the calibration method includes: when the steering wheel is at the physical horizontal 0° position, calibrating the steering wheel position at this time as the steering wheel 0° position, and recording the motor angle at this time as the second motor angle;

[0010] Steering wheel 0° position determination module: used to determine the steering wheel 0° position when the vehicle cannot obtain the current steering wheel 0° position. The determination method includes:

[0011] Obtaining a motor angle difference θ between the second motor angle and the first motor angle;

[0012] Turn the steering wheel from one extreme position to the other extreme position, and record the total rack stroke restored during this period, so that the restored total rack stroke is equal to the total rack stroke at the factory;

[0013] A third motor angle is obtained according to the motor angle corresponding to the midpoint of the restored total rack stroke and the motor angle difference θ, and the steering wheel position corresponding to the third motor angle is the steering wheel 0° position;

[0014] Steering wheel angle calculation module: used to calculate the vehicle's steering wheel angle signal based on the motor angle when the vehicle's steering wheel is turned, the motor angle corresponding to the steering wheel 0° position, and the angular transmission ratio between the steering wheel and the motor.

[0015] Furthermore, in the initial calibration module, the steering wheel is operated to turn from the middle position to the extreme position on one side, and a torque greater than a set torque value T is applied at the extreme position on one side and maintained for a set time; when the torque is equal to the set torque value T, the extreme position is recorded as the starting point of the total rack stroke at the factory;

[0016] The steering wheel is operated to rotate from the extreme position on one side to the extreme position on the other side, and a torque greater than a set torque value T is applied at the extreme position on the other side and maintained for a set time; when the torque is equal to the set torque value T, the extreme position is recorded as the end point of the total rack travel at the factory;

[0017] The total rack travel at the factory is obtained based on the starting point and end point of the total rack travel at the factory.

[0018] In the initial calibration module, the starting and ending points of the rack travel are recorded by applying a torque greater than the set torque value T and maintaining it for a set period of time, so as to more accurately obtain the total rack travel at the factory. When the steering wheel 0° position is lost later, the steering wheel 0° position can be accurately restored.

[0019] Furthermore, in the steering wheel 0° position determination module, when the steering wheel is rotated from one extreme position to the other extreme position, a torque greater than the set torque value T is applied and maintained for a set time;

[0020] When the steering wheel is at the extreme position on one side and the torque is equal to the set torque value T, the extreme position is recorded as the starting point of the total rack stroke restored;

[0021] When the steering wheel is at the extreme position on the other side, when the torque is equal to the set torque value T, the extreme position is recorded as the end point of the total rack stroke restored;

[0022] The restored total rack travel is obtained based on the starting point and end point of the restored total rack travel.

[0023] In the steering wheel 0° position determination module, the starting point and end point of the restored total rack travel are recorded by applying a torque greater than the set torque value T and maintaining the set time, thereby obtaining the restored total rack travel. This method ensures the stability of the steering wheel at the extreme position and further improves the accuracy of the steering wheel 0° position determination.

[0024] Furthermore, the steering wheel angle signal is calculated according to the following formula:

[0025] steering wheel angle_CEPS raw

[0026] =[N*360+(Motor angle_c-Motor angle_b)] / n

[0027] steering wheel angle_CEPS raw is the steering wheel angle signal;

[0028] Motor angle_b is the motor angle corresponding to the steering wheel position of 0°;

[0029] Motor angle_c is the motor angle when the steering wheel is turned;

[0030] n is the angular transmission ratio between the steering wheel and the motor;

[0031] N is the number of full revolutions of the motor when the steering wheel is turned.

[0032] Furthermore, the method further includes determining a first precondition. When the vehicle satisfies the first precondition, the steering rack travel of the vehicle is calibrated. The first precondition includes:

[0033] The vehicle has completed the four-wheel alignment parameter adjustment; the vehicle has not completed the calibration of the steering rack travel; the vehicle speed is 0, and the powertrain is in the starting state.

[0034] By adding the determination of the first precondition, it is ensured that the steering wheel angle control parameters are calibrated only when the vehicle meets specific conditions, thus avoiding unnecessary calibration operations and improving calibration efficiency.

[0035] Furthermore, the method further includes determining a second precondition. When the vehicle satisfies the second precondition, the 0° position of the vehicle steering wheel is calibrated. The second precondition includes:

[0036] The vehicle has completed the calibration of the steering rack travel; the vehicle speed is 0 and the powertrain is in the starting state.

[0037] By adding the judgment of the second precondition, it is ensured that the steering wheel 0° position calibration is performed only when the vehicle has completed the calibration of the steering gear rack travel and meets specific conditions, which further improves the accuracy and reliability of the calibration.

[0038] Furthermore, a correction module is included, which is used to correct the steering wheel angle signal. The correction method includes:

[0039] Send the steering wheel angle signal to the vehicle CAN network;

[0040] The steering angle compensation value is calculated by the left and right wheel speed difference and the yaw rate gain and sent to the CAN network;

[0041] The sum of the steering wheel angle compensation value and the steering wheel angle signal is calculated as the corrected steering wheel angle signal.

[0042] By adding a correction module to correct the steering wheel angle signal, the accuracy of the steering wheel angle signal is improved. This method takes into account factors such as the left and right wheel speed difference and the yaw rate gain, and calculates the angle compensation value and adds it to the steering wheel angle signal to obtain the corrected steering wheel angle signal. This method can better reflect the actual driving state of the vehicle and improve the accuracy and safety of vehicle control.

[0043] An indirect steering wheel angle control method for achieving the second objective of the present invention comprises:

[0044] Calibrate the steering rack travel of the vehicle to obtain the total rack travel and the first motor angle before leaving the factory; the calibration method includes:

[0045] The steering wheel is rotated from one extreme position to the other extreme position and the total rack travel of the motor at the factory during this period is recorded, and the motor angle corresponding to the midpoint of the total rack travel at the factory is calibrated as the first motor angle;

[0046] Calibrate the 0° position of the steering wheel; the calibration method includes: when the steering wheel is at a physical horizontal 0° position, calibrate the steering wheel position at this time as the steering wheel 0° position, and record the motor angle at this time as the second motor angle;

[0047] When the vehicle cannot obtain the current steering wheel 0° position, the steering wheel 0° position is determined, and the determination method includes:

[0048] Obtaining a motor angle difference θ between the second motor angle and the first motor angle;

[0049] Turn the steering wheel from one extreme position to the other extreme position, and record the total rack stroke restored during this period, so that the restored total rack stroke is equal to the total rack stroke at the factory;

[0050] A third motor angle is obtained according to the motor angle corresponding to the midpoint of the restored total rack stroke and the motor angle difference θ, and the steering wheel position corresponding to the third motor angle is the steering wheel 0° position;

[0051] The vehicle's steering wheel angle signal is calculated based on the motor angle when the vehicle's steering wheel is turned, the motor angle corresponding to the steering wheel's 0° position, and the angular transmission ratio between the steering wheel and the motor.

[0052] The beneficial effects of the present invention include:

[0053] Under the premise that the steering wheel angle sensor is eliminated in the vehicle, the present invention outputs an accurate and reliable steering wheel angle signal through mutual verification and compensation of EPS and ESC on the position of the power-assisting motor and the output steering wheel angle, which not only meets the requirements of various functions of the vehicle for the steering wheel angle signal, but also achieves the purpose of reducing costs by eliminating physical parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a schematic diagram of the steering wheel angle calibration process;

[0055] Figure 2 It is a schematic diagram of rack travel calibration;

[0056] Figure 3 It is a schematic diagram of the motor rotation during the steering wheel rotation. DETAILED DESCRIPTION

[0057] The following specific implementations are used to explain the technical solutions of the claims of the present invention so that those skilled in the art can understand the claims. The protection scope of the present invention is not limited to the following specific implementation structures. The technical solutions of the claims of the present invention made by those skilled in the art but different from the following specific implementations are also within the protection scope of the present invention.

[0058] Example 1

[0059] An indirect steering wheel angle control method

[0060] Step 1: Calibrate the rack travel of the steering gear, a steering system component;

[0061] Step 2: Calibrate the steering wheel angle 0° position of the steering system part CEPS (Column Electric Power Steering);

[0062] Step 3: Calculate the steering wheel angle signal based on the steering wheel angle 0° position and the current motor position.

[0063] In the above step 1, the triggering method of the rack travel calibration includes:

[0064] The driver manipulates the steering wheel to turn the steering wheel from the middle position to the extreme position on one side, applies a torque greater than T at the extreme position on the one side and maintains it for 1 second;

[0065] The driver operates the steering wheel to rotate from the extreme position on one side to the extreme position on the other side, and applies a torque greater than T at the extreme position on the other side and maintains it for 1 second;

[0066] The driver returns the steering wheel to the middle position and releases the steering wheel, and the PMIC module of the CEPS ECU begins to calibrate the steering rack travel.

[0067] After the calibration is completed, the rack travel calibration status changes from uncalibrated to calibrated, and the instrument steering wheel warning light changes from red to yellow.

[0068] In the above step 1, the calibration method of the rack stroke includes:

[0069] When the torque of the steering wheel to the extreme position on one side (such as the left extreme position) reaches T, the CEPS ECU detects the torque through the CEPS torque sensor and triggers the rack travel calculation program, setting the extreme position as the starting point of the total rack travel L at the factory;

[0070] When the torque of the steering wheel turning to the extreme position on the other side (such as the right extreme position) reaches T, the CEPS ECU detects the torque through the CEPS torque sensor and triggers the rack travel calculation program, setting the extreme position as the end point of the total rack travel L at the factory;

[0071] When the steering wheel is turned back to the middle position and released, the CEPS ECU detects that there is no torque on the steering wheel through the CEPS torque sensor, and the PMIC module starts to calculate the total rack stroke L between the starting point and the end point of the rack stroke, and obtains the steering wheel position O corresponding to the midpoint of the total rack stroke L at the factory through the total rack stroke L at the factory; and the motor position a corresponding to the steering wheel position, and the motor angle recorded at this time is Motor angle_a; and the motor angle corresponding to the total rack stroke L at the factory and the motor position a is stored in the CEPS controller as Motor angle_a.

[0072] The technical effects brought about by the above-mentioned setting of torque T include: due to factors such as the deformation of the limiting parts in the extreme position of the steering gear, when the steering wheel is turned to the extreme position, if the steering wheel torque continues to increase, the rack stroke will continue to increase due to the deformation of the limiting parts; by setting the torque T to trigger the calculation of the starting and end points of the rack stroke, the inconsistency of the total rack stroke L at the factory caused by the different operating forces of different operators at the extreme positions can be avoided (for example, if T is not set, when the operating force is less than T, the rack stroke calibration is triggered, and L will become smaller; when the operating force is greater than T, the rack stroke calibration is triggered, and L will be larger).

[0073] In the above step 1, before calibrating the rack stroke, it also includes the determination of the first precondition. Only when the vehicle meets the first precondition can the rack stroke be calibrated. The first precondition includes: the vehicle completes the four-wheel alignment parameter adjustment; the vehicle instrument steering wheel warning light is displayed in red (used to indicate that the rack stroke calibration status is uncalibrated, that is, the vehicle has not completed the calibration of the steering gear rack stroke); the vehicle speed is 0, and the powertrain is in the starting state.

[0074] The above-mentioned step 2 also includes the determination of the second precondition before calibrating the steering wheel angle 0° position. The steering wheel angle 0° position can be calibrated only when the vehicle meets the second precondition. The second precondition includes: the vehicle completes the calibration of the steering gear rack stroke; the vehicle instrument steering wheel warning light is displayed in yellow (used to indicate that the rack stroke is in a calibrated state, but the vehicle is in a state where the steering wheel angle 0° position is not calibrated); the vehicle speed is 0, and the powertrain is in the starting state.

[0075] In the above step 2, the calibration method of the steering wheel angle 0° position includes:

[0076] The steering wheel angle measuring instrument is fixed on the steering wheel to ensure that the steering wheel is in the physically horizontal 0° position;

[0077] VEP (a device for online calibration and flashing of electrical device controllers) is connected to the vehicle diagnostic port to calibrate the steering wheel angle 0° position of the CEPS in the current position; it also includes: when VEP writes the steering wheel angle 0° position into the CEPS, the PMIC records the corresponding position of the steering wheel at this time as the steering wheel position O'; the motor position corresponding to the steering wheel position is recorded as b, and the motor angle recorded at this time is Motor angle_b.

[0078] In some embodiments, the PMIC calculates the motor angle difference θ between the steering wheel position O corresponding to the midpoint of the rack travel and the steering wheel position O′ and stores the calculated difference in the motor angle in the CEPS controller.

[0079] In some embodiments, when the user disconnects the 12V battery during use or due to vehicle maintenance, the CEPS will lose the signal of the steering wheel angle 0° position due to the loss of power supply; when the total rack stroke L' is restored by the calibration method of the rack stroke, the PMIC can obtain the restored steering wheel position O, and the steering wheel angle 0° position O' can be restored by the position O and the steering wheel angle difference θ stored in the CEPS controller. In the calibration method of the rack stroke, the torque T is judged to ensure that the total rack stroke L' restored in the process is consistent with the total rack stroke L at the factory; the recovery method includes:

[0080] The motor angle angel1 corresponding to the restored steering wheel angle of 0° is calculated according to the following formula:

[0081] angel1 = θ + the corresponding motor angle corresponding to the midpoint of the restored total rack travel L';

[0082] The steering wheel position corresponding to the motor angle angel1 is the restored steering wheel angle 0° position O'.

[0083] In the above step 3, after VEP writes the steering wheel angle 0°, the CEPS PMIC module calculates the original steering wheel angle signal steering wheel angle-CEPSraw in real time by converting the angle of rotation of the CEPS power motor when the steering wheel is turned. The calculation method of the original steering wheel angle signal is as follows: Figure 2 As shown, including:

[0084] The PMIC divides the motor into four quadrants during one rotation;

[0085] PMIC records the position of the motor when the steering wheel is at 0°, which is recorded as b. The corresponding motor angle at this time is Motor angle_b.

[0086] PIMC records the position of the motor when the steering wheel is turned, which is recorded as c. The corresponding motor angle at this time is Motorangle_c.

[0087] The PMIC records the number of full revolutions of the motor when the steering wheel is turned, which is recorded as N;

[0088] Combined with the angular transmission ratio n between the steering wheel and the motor, the original steering wheel angle signal can be calculated according to the following formula:

[0089] steering wheel angle_CEPS raw

[0090] =[N*360+(Motor angle_c-Motor angle_b)] / n

[0091] When the steering wheel angle is calibrated to 0° position, the yellow steering wheel warning light on the instrument disappears.

[0092] In some embodiments, the ESC further performs calibration compensation on the original steering wheel angle 0° position of the CEPS during vehicle driving. The calibration compensation method includes:

[0093] CEPS sends the raw steering wheel angle (steering wheel angle-CEPS raw) to the vehicle CAN network;

[0094] ESC can also determine the vehicle's driving status through vehicle parameters such as wheel speed sensor and yaw acceleration sensor, and perform real-time compensation for the original steering wheel angle (steering wheel angle-CEPS raw) to output the corrected steering wheel angle signal (steering wheel angle-ESC correct);

[0095] Theoretically, for a new car, steering wheel angle - ESC correct = steering wheel angle - CEPS raw, and the compensation value is 0.

[0096] When the user is using the vehicle, the chassis four-wheel alignment parameters change due to tire wear, wear and deformation of chassis elastic parts, etc.; the original steering wheel angle steering wheel angle-CEPS raw is 0 but the vehicle cannot go straight. At this time, ESC calculates the steering wheel angle compensation value steering wheel angle-offset through the monitored left and right wheel speed difference and yaw rate gain and sends it to the CAN network; at this time, steering wheelangle-ESC correct = steering wheel angle-CEPS raw + steering wheel angle-offset; CEPS uses the compensated steering wheel angle signal steering wheel angle-ESC correct to ensure the vehicle's straight-line driving stability;

[0097] At the same time, the compensated steering wheel angle signal steering wheel angle-ESC correct is used in the ESC body stability control system and ADAS intelligent driving system to realize various related functions.

[0098] Example 2

[0099] An indirect steering wheel angle control system, comprising:

[0100] Initial calibration module: used to calibrate the steering rack travel of the vehicle to obtain the total rack travel L and the first motor angle Motor angle_a when leaving the factory; the calibration method includes:

[0101] Turn the steering wheel from one extreme position to the other extreme position and record the total rack travel L of the motor at the factory during this period. Calibrate the motor angle corresponding to the midpoint of the total rack travel at the factory as the first motor angle Motorangle_a;

[0102] Steering wheel 0° position calibration module: used to calibrate the 0° position of the steering wheel; the calibration method includes: when the steering wheel is at the physical horizontal 0° position, calibrating the steering wheel position at this time as the steering wheel 0° position, and recording the motor angle at this time as the second motor angle Motor angle_b;

[0103] Steering wheel 0° position determination module: used to determine the steering wheel 0° position when the vehicle cannot obtain the current steering wheel 0° position. The determination method includes:

[0104] Obtaining a motor angle difference θ between the second motor angle Motor angle_b and the first motor angle Motor angle_a;

[0105] Turn the steering wheel from one extreme position to the other extreme position, and record the total rack stroke L' restored during this period, so that the total rack stroke L' restored is equal to the total rack stroke L at the factory;

[0106] A third motor angle is obtained according to the motor angle corresponding to the midpoint of the restored total rack stroke L' and the motor angle difference θ, and the steering wheel position corresponding to the third motor angle is the steering wheel 0° position; the third motor angle is equal to the sum of the motor angle corresponding to the midpoint of the restored total rack stroke L' and the motor angle difference θ;

[0107] Steering wheel angle calculation module: used to calculate the vehicle's steering wheel angle signal based on the motor angle Motor angle_c when the vehicle's steering wheel is turned, the motor angle Motor angle_b corresponding to the steering wheel 0° position, and the angular transmission ratio N between the steering wheel and the motor.

[0108] In some embodiments, in the initial calibration module, the steering wheel is turned from the middle position to the extreme position on one side, and a torque greater than a set torque value T is applied at the extreme position on one side and maintained for a set time; when the torque is equal to the set torque value T, the extreme position is recorded as the starting point of the total rack stroke at the factory;

[0109] The steering wheel is operated to rotate from the extreme position on one side to the extreme position on the other side, and a torque greater than a set torque value T is applied at the extreme position on the other side and maintained for a set time; when the torque is equal to the set torque value T, the extreme position is recorded as the end point of the total rack travel at the factory;

[0110] The total rack travel at the factory is obtained based on the starting point and end point of the total rack travel at the factory.

[0111] In some embodiments, in the steering wheel 0° position determination module, when the steering wheel is rotated from one extreme position to the other extreme position, a torque greater than a set torque value T is applied and maintained for a set time;

[0112] When the steering wheel is at the extreme position on one side and the torque is equal to the set torque value T, the extreme position is recorded as the starting point of the total rack stroke restored;

[0113] When the steering wheel is at the extreme position on the other side, when the torque is equal to the set torque value T, the extreme position is recorded as the end point of the total rack stroke restored;

[0114] The restored total rack travel is obtained based on the starting point and end point of the restored total rack travel.

[0115] In some embodiments, the steering wheel angle signal is calculated according to the following formula:

[0116] steering wheel angle_CEPS raw

[0117] =[N*360+(Motor angle_c-Motor angle_b)] / n

[0118] steering wheel angle_CEPS raw is the steering wheel angle signal;

[0119] Motor angle_b is the motor angle corresponding to the steering wheel position of 0°;

[0120] Motor angle_c is the motor angle when the steering wheel is turned;

[0121] n is the angular transmission ratio between the steering wheel and the motor;

[0122] N is the number of full revolutions of the motor when the steering wheel is turned.

[0123] In some embodiments, the method further includes determining a first precondition. When the vehicle satisfies the first precondition, the steering rack travel of the vehicle is calibrated. The first precondition includes:

[0124] The vehicle has completed the four-wheel alignment parameter adjustment; the vehicle has not completed the calibration of the steering rack travel; the vehicle speed is 0, and the powertrain is in the starting state.

[0125] In some embodiments, the second precondition is further determined. When the vehicle satisfies the second precondition, the 0° position of the vehicle steering wheel is calibrated. The second precondition includes:

[0126] The vehicle has completed the calibration of the steering rack travel; the vehicle speed is 0 and the powertrain is in the starting state.

[0127] In some embodiments, a correction module is further included, for correcting the steering wheel angle signal, and the correction method includes:

[0128] Send the steering wheel angle signal to the vehicle CAN network;

[0129] The steering angle compensation value is calculated by the left and right wheel speed difference and the yaw rate gain and sent to the CAN network;

[0130] The sum of the steering wheel angle compensation value and the steering wheel angle signal is calculated as the corrected steering wheel angle signal.

[0131] Example 3

[0132] An indirect steering wheel angle control method, comprising:

[0133] Calibrate the steering rack travel of the vehicle to obtain the total rack travel and the first motor angle before leaving the factory; the calibration method includes:

[0134] The steering wheel is rotated from one extreme position to the other extreme position and the total rack travel of the motor at the factory during this period is recorded, and the motor angle corresponding to the midpoint of the total rack travel at the factory is calibrated as the first motor angle;

[0135] Calibrate the 0° position of the steering wheel; the calibration method includes: when the steering wheel is at a physical horizontal 0° position, calibrate the steering wheel position at this time as the steering wheel 0° position, and record the motor angle at this time as the second motor angle;

[0136] When the vehicle cannot obtain the current steering wheel 0° position, the steering wheel 0° position is determined, and the determination method includes:

[0137] Obtaining a motor angle difference θ between the second motor angle and the first motor angle;

[0138] Turn the steering wheel from one extreme position to the other extreme position, and record the total rack stroke restored during this period, so that the restored total rack stroke is equal to the total rack stroke at the factory;

[0139] A third motor angle is obtained according to the motor angle corresponding to the midpoint of the restored total rack stroke and the motor angle difference θ, and the steering wheel position corresponding to the third motor angle is the steering wheel 0° position;

[0140] The vehicle's steering wheel angle signal is calculated based on the motor angle when the vehicle's steering wheel is turned, the motor angle corresponding to the steering wheel's 0° position, and the angular transmission ratio between the steering wheel and the motor.

[0141] Example 4

[0142] A non-transitory computer-readable storage medium stores a computer program, wherein the computer program includes program instructions. When the program instructions are executed by a processor, the various steps of the method described in the present invention are implemented, which will not be repeated here.

[0143] The computer-readable storage medium may be the data transmission device provided in any of the aforementioned embodiments or the internal storage unit of the computer device, such as the hard disk or memory of the computer device. The computer-readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, a smart memory card (smartmedia card, SMC), a secure digital (secure digital, SD) card, a flash card (flash card), etc., provided on the computer device.

[0144] Furthermore, the computer-readable storage medium may include both an internal storage unit of the computer device and an external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by the computer device. The computer-readable storage medium may also be used to temporarily store data to be output or has been output.

[0145] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0146] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0147] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0148] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0149] Example 5

[0150] A computer program product comprises a computer program / instruction, which implements the steps of the indirect steering wheel angle control method when executed by a processor.

[0151] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. An indirect steering wheel angle control system, characterized in that: include: Initial calibration module: used to calibrate the steering rack travel of the vehicle to obtain the total rack travel and the first motor angle at the factory; The calibration method comprises: The steering wheel is rotated from one extreme position to the other extreme position and the total rack travel of the motor at the factory during this period is recorded, and the motor angle corresponding to the midpoint of the total rack travel at the factory is calibrated as the first motor angle; Steering wheel 0° position calibration module: used to calibrate the 0° position of the steering wheel; and record the motor angle at this time as the second motor angle; Steering wheel 0° position determination module: used to determine the steering wheel 0° position when the vehicle cannot obtain the current steering wheel 0° position. The determination method includes: Obtaining a motor angle difference θ between the second motor angle and the first motor angle; Turn the steering wheel from one extreme position to the other extreme position, and record the total rack stroke restored during this period, so that the restored total rack stroke is equal to the total rack stroke at the factory; A third motor angle is obtained according to the motor angle corresponding to the midpoint of the restored total rack stroke and the motor angle difference θ, and the steering wheel position corresponding to the third motor angle is the steering wheel 0° position; Steering wheel angle calculation module: used to calculate the vehicle's steering wheel angle signal based on the motor angle when the vehicle's steering wheel is turned, the motor angle corresponding to the steering wheel 0° position, and the angular transmission ratio between the steering wheel and the motor.

2. The indirect steering wheel angle control system according to claim 1, characterized in that: In the initial calibration module, the steering wheel is turned from the middle position to the extreme position on one side, and a torque greater than a set torque value T is applied at the extreme position on one side and maintained for a set time; When the torque is equal to the set torque value T, the limit position is recorded as the starting point of the total rack travel at the factory; The steering wheel is operated to rotate from the extreme position on one side to the extreme position on the other side, and a torque greater than a set torque value T is applied at the extreme position on the other side and maintained for a set time; When the torque is equal to the set torque value T, the limit position is recorded as the end point of the total rack travel at the factory.

3. The indirect steering wheel angle control system according to claim 2, characterized in that: In the steering wheel 0° position determination module, when the steering wheel is turned from one extreme position to the other extreme position, a torque greater than the set torque value T is applied and maintained for a set time; When the steering wheel is at the extreme position on one side and the torque is equal to the set torque value T, the extreme position is recorded as the starting point of the total rack stroke restored; When the steering wheel is located at the extreme position on the other side, when the torque is equal to the set torque value T, the extreme position is recorded as the end point of the restored total rack stroke.

4. The indirect steering wheel angle control system according to claim 1, characterized in that: The steering wheel angle signal is calculated according to the following formula: steering wheel angle_CEPS raw =[N*360+(Motor angle_c-Motor angle_b)] / n steering wheel angle_CEPS raw is the steering wheel angle signal; Motor angle_b is the motor angle corresponding to the steering wheel position of 0°; Motor angle_c is the motor angle when the steering wheel is turned; n is the angular transmission ratio between the steering wheel and the motor; N is the number of full revolutions of the motor when the steering wheel is turned.

5. The indirect steering wheel angle control system according to claim 1, characterized in that: The method further includes determining a first precondition. When the vehicle satisfies the first precondition, the steering rack travel of the vehicle is calibrated. The first precondition includes: The vehicle has completed the four-wheel alignment parameter adjustment; the vehicle has not completed the calibration of the steering rack travel; the vehicle speed is 0, and the powertrain is in the starting state.

6. The indirect steering wheel angle control system according to claim 1, characterized in that: The method further includes determining a second precondition, and when the vehicle satisfies the second precondition, calibrating the 0° position of the vehicle steering wheel, wherein the second precondition includes: The vehicle has completed the calibration of the steering rack travel; the vehicle speed is 0 and the powertrain is in the starting state.

7. The indirect steering wheel angle control system according to claim 1, characterized in that: It also includes a correction module for correcting the steering wheel angle signal, and the correction method includes: Send the steering wheel angle signal to the vehicle CAN network; The steering angle compensation value is calculated by the left and right wheel speed difference and the yaw rate gain and sent to the CAN network; The sum of the steering wheel angle compensation value and the steering wheel angle signal is calculated as the corrected steering wheel angle signal.

8. An indirect steering wheel angle control method of the system as claimed in claim 1, characterized in that: include: Calibrate the steering rack travel of the vehicle to obtain the total rack travel and the first motor angle at the factory; The calibration method comprises: The steering wheel is rotated from one extreme position to the other extreme position and the total rack travel of the motor at the factory during this period is recorded, and the motor angle corresponding to the midpoint of the total rack travel at the factory is calibrated as the first motor angle; Calibrate the 0° position of the steering wheel; and record the motor angle at this time as the second motor angle; When the vehicle cannot obtain the current 0° position of the steering wheel, the 0° position of the steering wheel is determined, and the determination method includes: Obtaining a motor angle difference θ between the second motor angle and the first motor angle; Turn the steering wheel from one extreme position to the other extreme position, and record the total rack stroke restored during this period, so that the restored total rack stroke is equal to the total rack stroke at the factory; A third motor angle is obtained according to the motor angle corresponding to the midpoint of the restored total rack stroke and the motor angle difference θ, and the steering wheel position corresponding to the third motor angle is the steering wheel 0° position; The vehicle's steering wheel angle signal is calculated based on the motor angle when the vehicle's steering wheel is turned, the motor angle corresponding to the steering wheel's 0° position, and the angular transmission ratio between the steering wheel and the motor.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the indirect steering wheel angle control method as claimed in claim 8 are implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the indirect steering wheel angle control method of claim 8 are implemented.

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