An indirect steering wheel angle control system, method, storage medium, and computer program product.

Abstract

This invention discloses an indirect steering wheel angle control system, method, storage medium, and computer program product. By eliminating the steering wheel angle sensor in the vehicle, this invention calculates the position of the power steering motor using EPS and ESC, and performs mutual verification and compensation to output a precise and reliable steering wheel angle signal. This satisfies the steering wheel angle signal requirements of various vehicle functions and also reduces costs by eliminating physical components.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control technology, specifically relating to an indirect steering wheel angle control system, method, storage medium, and computer program product. Background Technology

[0002] With the development of the automotive industry and the rise of new energy vehicles and intelligent vehicles, competition among OEMs is becoming increasingly fierce. To enhance brand competitiveness, OEMs are simultaneously increasing product appeal by adding advanced features such as driver assistance and autonomous driving, while also increasing profit margins through cost-reduction designs.

[0003] As a core component that meets the steering needs of a vehicle during driving, the steering system must satisfy the requirements of increasingly sophisticated ADAS intelligent driving functions, as well as the driver's demands for handling stability and driving comfort. Stable, reliable, and precise steering wheel angle signals are fundamental conditions for achieving excellent vehicle steering performance, ESC vehicle stability control, and various ADAS intelligent driving functions.

[0004] Currently, vehicles on the market use steering wheel angle sensors to provide the necessary steering angle signals for steering, ESC (Electronic Stability Control), and ADAS (Advanced Driver Assistance Systems) intelligent driving functions. However, existing steering wheel angle sensors in commercially available vehicles are typically modular, pre-defined components from suppliers. During vehicle design and development, OEMs need to reserve assembly interfaces based on the component's shape and signal definition and perform software signal matching, which adds complexity to the design and development process. Summary of the Invention

[0005] In order to enable vehicles to obtain accurate and reliable steering wheel angle signals without the need for a steering wheel angle sensor, this invention proposes an indirect steering wheel angle control system, method, storage medium, and computer program product.

[0006] An indirect steering wheel angle control system, comprising: [The system aims to achieve one of the objectives of this invention.]

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

[0008] Turn the steering wheel from one extreme position to the other extreme position and record the total rack travel of the motor during this period. 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, the steering wheel position at this time is calibrated as the steering wheel 0° position, and the motor angle at this time is recorded 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] Obtain the 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 travel recovered during this period, so that the recovered total rack travel is equal to the total rack travel at the factory.

[0013] The third motor angle is obtained based on the motor angle corresponding to the midpoint of the recovered total rack travel and the motor angle difference θ. The steering wheel position corresponding to the third motor angle is the 0° position of the steering wheel.

[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 0° position of the steering wheel, and the angular transmission ratio between the steering wheel and the motor.

[0015] Furthermore, in the initial calibration module, the steering wheel is turned from the middle position to one extreme position, and a torque greater than the set torque value T is applied to the one extreme position and held for a set duration; when the torque is equal to the set torque value T, the extreme position is recorded as the starting point of the total rack travel at the factory.

[0016] Maneuver the steering wheel from one extreme position to the other extreme position, apply a torque greater than the set torque value T at the other extreme position and hold for a set duration; when the torque equals the set torque value T, record this extreme position as the end point of the total rack travel at the factory.

[0017] The total rack travel at the time of manufacture is obtained from the start and end points of the total rack travel at the time of manufacture.

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

[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 held for a set duration;

[0020] When the steering wheel is at its extreme position on one side, and the torque is equal to the set torque value T, record this extreme position as the starting point of the total rack travel to be restored.

[0021] When the steering wheel is at its extreme position on the other side, and the torque is equal to the set torque value T, record this extreme position as the end point of the total rack travel recovered.

[0022] The recovered total rack travel is obtained from the start and end points of the recovered total rack travel.

[0023] In the steering wheel 0° position determination module, a torque greater than the set torque value T is applied and held for a set duration to record the start and end points of the recovered total rack travel, thus obtaining the recovered total rack travel. This method ensures the stability of the steering wheel at its extreme positions and further improves the accuracy of determining the steering wheel 0° position.

[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 0° position of the steering wheel;

[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 represents the number of full revolutions the motor makes when the steering wheel is turned.

[0032] Furthermore, it also includes determining a first precondition. When the vehicle meets the first precondition, the steering rack travel of the vehicle is calibrated. The first precondition includes:

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

[0034] By adding a determination of the first prerequisite, 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, it also includes determining a second precondition. When the vehicle meets the second precondition, the 0° position of the vehicle's 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 a second prerequisite condition, the system ensures that the steering wheel 0° position is calibrated only when the vehicle has completed the calibration of the steering rack travel and meets specific conditions, thus further improving the accuracy and reliability of the calibration.

[0038] Furthermore, it also includes a correction module for correcting the steering wheel angle signal, the correction method including:

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

[0040] The steering angle compensation value is calculated based on the speed difference between the left and right wheels and the yaw rate gain, and then sent to the CAN network.

[0041] The sum of the steering 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 adjust the steering wheel angle signal, the accuracy of the steering wheel angle signal is improved. This method considers factors such as the speed difference between the left and right wheels and the yaw rate gain. By calculating the angle compensation value and adding it to the steering wheel angle signal, the corrected steering wheel angle signal is obtained. This method can better reflect the actual driving state of the vehicle, improving the precision and safety of vehicle handling.

[0043] A second objective of this invention is an indirect steering wheel angle control method, comprising:

[0044] The vehicle's steering rack travel is calibrated to obtain the total rack travel and first motor angle at the factory setting; the calibration method includes:

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

[0046] The 0° position of the steering wheel is calibrated. The calibration method includes: when the steering wheel is at the physical horizontal 0° position, the position of the steering wheel at this time is calibrated as the 0° position of the steering wheel, and the motor angle at this time is recorded as the second motor angle.

[0047] When the vehicle cannot obtain the current 0° position of the steering wheel, the 0° position of the steering wheel is determined using methods including:

[0048] Obtain the 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 travel recovered during this period, so that the recovered total rack travel is equal to the total rack travel at the factory.

[0050] The third motor angle is obtained based on the motor angle corresponding to the midpoint of the recovered total rack travel and the motor angle difference θ. The steering wheel position corresponding to the third motor angle is the 0° position of the steering wheel.

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

[0052] The beneficial effects of this invention include:

[0053] This invention eliminates the steering wheel angle sensor in the vehicle. By using EPS and ESC to calculate the position of the power steering motor and to mutually verify and compensate the output steering wheel angle, it outputs a precise and reliable steering wheel angle signal. This satisfies the steering wheel angle signal requirements of various vehicle functions and also reduces costs by eliminating physical parts. Attached Figure Description

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

[0055] Figure 2 This is a schematic diagram of rack and pinion travel calibration;

[0056] Figure 3 This is a diagram illustrating the motor's rotation during steering wheel rotation. Detailed Implementation

[0057] The following detailed embodiments are provided to explain the technical solutions of the claims of this invention, so that those skilled in the art can understand the claims. The scope of protection of this invention is not limited to the following specific embodiments. Any modifications made by those skilled in the art that incorporate the technical solutions of the claims but differ from the following detailed embodiments are also within the scope of protection of this invention.

[0058] Example 1

[0059] An indirect steering wheel angle control method

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

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

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

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

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

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

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

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

[0068] In step 1 above, the calibration method for the rack travel includes:

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

[0070] When the torque reaches T when the steering wheel is turned to the other extreme position (such as the right extreme position), the CEPS ECU detects the torque through the CEPS torque sensor and triggers the rack travel calculation program to set 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 center position and released, the CEPS ECU detects no torque on the steering wheel through the CEPS torque sensor. The PMIC module starts to calculate the total rack travel L between the start and end points of the rack travel, and obtains the steering wheel position O corresponding to the midpoint of the total rack travel L at the factory setting; and the motor position a corresponding to the steering wheel position. The motor angle recorded at this time is Motor angle_a; and the total rack travel L at the factory setting and the motor angle corresponding to the motor position a are stored in the CEPS controller.

[0072] The technical effects of setting the torque T mentioned above include: due to factors such as deformation of the limit components inside the steering gear, when the steering wheel is turned to the limit position, if the steering wheel torque is continuously increased, the rack travel will continue to increase due to the deformation of the limit components; by setting the torque T to trigger the calculation of the start and end points of the rack travel, the inconsistency of the total rack travel L at the factory caused by different operating forces of different operators at the limit position can be avoided (for example, without setting T, when the operating force is less than T, the rack travel calibration is triggered, and L will be smaller; when the operating force is greater than T, the rack travel calibration is triggered, and L will be larger).

[0073] In step 1 above, before calibrating the rack travel, a first prerequisite condition is determined. The rack travel can only be calibrated when the vehicle meets the first prerequisite condition. The first prerequisite condition includes: the vehicle has completed the four-wheel alignment parameter adjustment; the vehicle instrument steering wheel warning light is red (to indicate that the rack travel calibration status is uncalibrated, that is, 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.

[0074] Step 2 above includes determining a second prerequisite before calibrating the 0° steering wheel angle. The 0° steering wheel angle can only be calibrated when the vehicle meets the second prerequisite. The second prerequisite includes: the vehicle has completed the calibration of the steering rack travel; the steering wheel warning light on the vehicle's instrument panel is yellow (indicating that the rack travel is in a calibrated state, but the vehicle is in a state where the steering wheel angle 0° is not calibrated); the vehicle speed is 0; and the powertrain is in the starting state.

[0075] Step 2 above, the calibration method for the 0° steering wheel angle position includes:

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

[0077] The VEP (a device for online calibration and rewriting of electronic component controllers) connects to the vehicle diagnostic port to calibrate the steering wheel angle at 0° in the current CEPS. This also includes: when the VEP writes the steering wheel angle 0° into the CEPS, the PMIC records the corresponding steering wheel position as steering wheel position O'; the motor position corresponding to this steering wheel position is recorded as b, and the recorded motor angle 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 it in the CEPS controller.

[0079] In some embodiments, when the battery is depleted during use or the 12V battery is disconnected for vehicle maintenance, the CEPS loses the signal for the 0° steering wheel position due to the loss of power supply. When the total rack travel L' is recovered using the rack travel calibration method, the PMIC can obtain the recovered steering wheel position O. By comparing this position O with the steering wheel angle difference θ stored in the CEPS controller, the 0° steering wheel position O' can be recovered. The rack travel calibration method uses torque T to ensure that the recovered total rack travel L' is consistent with the factory-set total rack travel L. The recovery method includes:

[0080] Calculate the motor angle angel1 corresponding to the position where the steering wheel angle is 0° after restoration using the following formula:

[0081] angel1 = θ + the motor rotation angle corresponding to the midpoint of the recovered total rack stroke L';

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

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

[0084] PMIC divides the motor's rotation into 4 quadrants;

[0085] The PMIC records the position of the motor when the steering wheel is at 0°, and records it 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 the motor makes when the steering wheel is turned, and records it as N;

[0088] Based on the angular transmission ratio n between the steering wheel and the motor, the original steering wheel angle signal can be calculated using the following formula:

[0089] steering wheel angle_CEPS raw

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

[0091] Once the steering wheel angle is calibrated to 0°, the yellow warning light on the steering wheel on the instrument panel will disappear.

[0092] In some embodiments, the method further includes verifying and compensating for the original 0° steering wheel angle position of the CEPS during vehicle operation. The verification and compensation method includes:

[0093] CEPS sends the raw steering wheel angle (CEPS raw) to the vehicle's CAN network.

[0094] ESC can determine the vehicle's driving status by using vehicle parameters such as wheel speed sensor and yaw acceleration sensor, and can also perform real-time compensation on the original steering wheel angle (CEPS raw) and output the corrected steering wheel angle signal (Steering Wheel Angle - ESC Correct).

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

[0096] When a user uses a vehicle, the chassis four-wheel alignment parameters may change due to tire wear, wear and deformation of chassis elastic parts, etc. This can lead to situations where the original steering wheel angle (CEPS raw) is 0, but the vehicle cannot move straight. In this case, ESC calculates the steering wheel angle compensation value (steering wheel angle-offset) by monitoring the speed difference between the left and right wheels and the yaw rate gain, and sends it to the CAN network. At this point, steering wheel angle-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] Meanwhile, the compensated steering wheel angle signal (ESC correct) is used in the ESC vehicle stability control system and ADAS intelligent driving system to achieve their respective functions.

[0098] Example 2

[0099] An indirect steering wheel angle control system includes:

[0100] Initial calibration module: used to calibrate the steering rack travel of the vehicle, obtaining the total rack travel L and the first motor angle_a at the factory setting; the calibration method includes:

[0101] Rotate 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. The motor angle corresponding to the midpoint of the total rack travel at the factory is calibrated 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, the steering wheel position at this time is calibrated as the steering wheel 0° position, and the motor angle at this time is recorded 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] Obtain the motor angle difference θ between the second motor angle_b and the first motor angle_a;

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

[0106] The third motor angle is obtained based on the motor angle corresponding to the midpoint of the recovered total rack travel L' and the motor angle difference θ. The steering wheel position corresponding to the third motor angle is the 0° steering wheel position. The third motor angle is equal to the sum of the motor angle corresponding to the midpoint of the recovered total rack travel 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_c when the vehicle's steering wheel is turned, the motor angle_b corresponding to the 0° position of the steering wheel, 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 center position to one extreme position, a torque greater than a set torque value T is applied at the extreme position and held for a set duration; when the torque equals the set torque value T, the extreme position is recorded as the starting point of the total rack travel at the factory.

[0109] Maneuver the steering wheel from one extreme position to the other extreme position, apply a torque greater than the set torque value T at the other extreme position and hold for a set duration; when the torque equals the set torque value T, record this extreme position as the end point of the total rack travel at the factory.

[0110] The total rack travel at the time of manufacture is obtained from the start and end points of the total rack travel at the time of manufacture.

[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 the set torque value T is applied and held for a set duration.

[0112] When the steering wheel is at its extreme position on one side, and the torque is equal to the set torque value T, record this extreme position as the starting point of the total rack travel to be restored.

[0113] When the steering wheel is at its extreme position on the other side, and the torque is equal to the set torque value T, record this extreme position as the end point of the total rack travel recovered.

[0114] The recovered total rack travel is obtained from the start and end points of the recovered 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 0° position of the steering wheel;

[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 represents the number of full revolutions the motor makes when the steering wheel is turned.

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

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

[0125] In some embodiments, the method further includes determining a second precondition. If the vehicle meets the second precondition, the 0° position of the vehicle's 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 also included for correcting the steering wheel angle signal, the correction method including:

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

[0129] The steering angle compensation value is calculated based on the speed difference between the left and right wheels and the yaw rate gain, and then sent to the CAN network.

[0130] The sum of the steering 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 includes:

[0133] The vehicle's steering rack travel is calibrated to obtain the total rack travel and first motor angle at the factory setting; the calibration method includes:

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

[0135] The 0° position of the steering wheel is calibrated. The calibration method includes: when the steering wheel is at the physical horizontal 0° position, the position of the steering wheel at this time is calibrated as the 0° position of the steering wheel, and the motor angle at this time is recorded as the second motor angle.

[0136] When the vehicle cannot obtain the current 0° position of the steering wheel, the 0° position of the steering wheel is determined using methods including:

[0137] Obtain the 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 travel recovered during this period, so that the recovered total rack travel is equal to the total rack travel at the factory.

[0139] The third motor angle is obtained based on the motor angle corresponding to the midpoint of the recovered total rack travel and the motor angle difference θ. The steering wheel position corresponding to the third motor angle is the 0° position of the steering wheel.

[0140] The steering wheel angle signal is calculated based on the motor angle when the vehicle's steering wheel rotates, the motor angle corresponding to the 0° position of the steering wheel, 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, the computer program including program instructions that, when executed by a processor, implement the various steps of the method described in this invention, which will not be elaborated further here.

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

[0144] Furthermore, the computer-readable storage medium may include both internal storage units and external storage devices of the computer 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 that is to be output or has already been output.

[0145] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, 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 magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0146] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0147] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The 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 operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0149] Example 5

[0150] A computer program product includes a computer program / instructions that, when executed by a processor, implement the steps of the indirect steering wheel angle control method.

[0151] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

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, obtaining the total rack travel and first motor angle at the factory setting; calibration methods include: Turn the steering wheel from one extreme position to the other extreme position and record the total rack travel of the motor during this period. 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: Obtain the 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 travel recovered during this period, so that the recovered total rack travel is equal to the total rack travel at the factory. The third motor angle is obtained based on the motor angle corresponding to the midpoint of the recovered total rack travel and the motor angle difference θ. The steering wheel position corresponding to the third motor angle is the 0° position of the steering wheel. 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 0° position of the steering wheel, and the angular transmission ratio between the steering wheel and the motor.

2. The indirect steering wheel angle control system as described in claim 1, characterized in that, In the initial calibration module, the steering wheel is turned from the middle position to one extreme position, and a torque greater than the set torque value T is applied at the one extreme position and held for a set duration. When the torque equals the set torque value T, record this extreme position as the starting point of the total rack stroke at the time of manufacture; Maneuver the steering wheel from one extreme position to the other extreme position, apply a torque greater than the set torque value T at the other extreme position and hold it for a set duration; When the torque equals the set torque value T, the extreme position is recorded as the end point of the total rack travel at the time of manufacture.

3. The indirect steering wheel angle control system as described in claim 2, characterized in that, 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 held for a set duration. When the steering wheel is at its extreme position on one side, and the torque is equal to the set torque value T, record this extreme position as the starting point of the total rack travel to be restored. When the steering wheel is at its extreme position on the other side, and the torque is equal to the set torque value T, record this extreme position as the end point of the total rack travel to be recovered.

4. The indirect steering wheel angle control system as described in claim 1, characterized in that, Calculate the steering wheel angle signal using 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 0° position of the steering wheel; 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 represents the number of full revolutions the motor makes when the steering wheel is turned.

5. The indirect steering wheel angle control system as described in claim 1, characterized in that, It also includes determining a first precondition. If the vehicle meets the first precondition, the steering rack travel of the vehicle is calibrated. The first precondition includes: The vehicle has completed four-wheel alignment parameter adjustment; the vehicle has not completed steering rack travel calibration; the vehicle speed is 0, and the powertrain is in the starting state.

6. The indirect steering wheel angle control system as described in claim 1, characterized in that, It also includes determining a second precondition. If the vehicle meets the second precondition, the 0° position of the vehicle's steering wheel is calibrated. 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 as described in claim 1, characterized in that, It also includes a correction module for correcting the steering wheel angle signal, and the correction methods include: Send the steering wheel angle signal to the vehicle's CAN network; The steering angle compensation value is calculated based on the speed difference between the left and right wheels and the yaw rate gain, and then sent to the CAN network. The sum of the steering 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 for the system as described in claim 1, characterized in that, include: The steering rack travel of the vehicle is calibrated to obtain the total rack travel and the first motor angle at the factory setting. The calibration method includes: Turn the steering wheel from one extreme position to the other extreme position and record the total rack travel of the motor during this period. The motor angle corresponding to the midpoint of the total rack travel at the factory is calibrated as the first motor angle. The steering wheel is calibrated at 0°; and the motor angle at this time is recorded 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 using methods including: Obtain the 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 travel recovered during this period, so that the recovered total rack travel is equal to the total rack travel at the factory. The third motor angle is obtained based on the motor angle corresponding to the midpoint of the recovered total rack travel and the motor angle difference θ. The steering wheel position corresponding to the third motor angle is the 0° position of the steering wheel. The steering wheel angle signal is calculated based on the motor angle when the vehicle's steering wheel rotates, the motor angle corresponding to the 0° position of the steering wheel, 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 the processor, it implements the steps of the indirect steering wheel angle control method as described in claim 8.

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

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