Vehicle steering system with torque steering mitigation and road angle detection

Abstract

The invention relates to a vehicle steering system with torque steering mitigation and road angle detection. A steering system for a vehicle includes an inertial measurement unit (IMU) configured to measure a first lateral acceleration of the vehicle. The torque sensor is configured to measure steering wheel torque. The steering control module is configured to receive a steering wheel torque and generate a steering wheel torque feedback. The torque steering mitigation module is configured to determine a torque steering component of a steering wheel torque feedback. The road angle detection module is configured to estimate a second lateral acceleration of the vehicle independent of a road angle on a road on which the vehicle travels, and selectively detect the road angle based on the first measured lateral acceleration from the IMU and the second lateral acceleration.

Description

[0001] The information provided in this section is for the purpose of generally presenting the background of this disclosure. The work of the currently attributed inventors, to the extent described in this section, and in respect of aspects that may not otherwise qualify as prior art at the time of filing, is neither expressly nor implied to be in conflict with the prior art of this disclosure. Technical Field

[0002] This disclosure relates to a steering system for a vehicle, and more particularly, to a steering system that supports torque steer mitigation and road angle detection. Background Technology

[0003] Torque steer can occur during acceleration in vehicles with a driven front axle. Torque steer is typically caused by the difference in torque between the left and right axles or the tire traction at the driven front axle during acceleration. A vehicle's power steering system can implement Torque Steering Mitigation (TSM) to reduce unwanted torque steer. The TSM system provides steering wheel torque feedback to counteract or compensate for torque steer. Summary of the Invention

[0004] A steering system for a vehicle includes an inertial measurement unit (IMU) configured to measure a first lateral acceleration of the vehicle. A torque sensor is configured to measure steering wheel torque. A steering control module is configured to receive the steering wheel torque and generate steering wheel torque feedback. A torque steering mitigation module is configured to determine the torque steering component of the steering wheel torque feedback. A road angle detection module is configured to estimate a second lateral acceleration of the vehicle independently of the road angle on the road the vehicle is traveling on, and to selectively detect the road angle based on the first measured lateral acceleration from the IMU and the second lateral acceleration.

[0005] Among other features, the torque steer mitigation module determines the torque steer component in response to torque steer learning. Torque steer learning utilizes a lookup table that outputs the steering torque indexed by the front axle torque. The torque steer mitigation module is configured to selectively pause torque steer learning in response to the road angle detection module detecting a road angle.

[0006] Among other features, the road angle detection module is configured to estimate the second lateral acceleration based on a first lateral force on the front axle of the vehicle. The road angle detection module is also configured to estimate the second lateral acceleration based on a second lateral force on the rear axle of the vehicle.

[0007] Among other features, the road angle detection module estimates a second lateral force on the rear axle of the vehicle based on yaw motion calculated in response to the IMU. The road angle detection module is configured to estimate a second lateral acceleration in response to a first lateral force on the front axle of the vehicle, a second lateral force on the rear axle of the vehicle, and the mass of the vehicle. The road angle detection module is also configured to detect when the vehicle is traveling at a road angle if the difference between the first measured lateral acceleration from the IMU and the second lateral acceleration is greater than a predetermined threshold. The road angle detection module is also configured to calculate the lateral force corresponding to the road angle.

[0008] Among other features, the road angle detection module is configured to estimate the road angle torque component of the steering wheel torque. The road angle detection module uses either a lookup table or a function, along with the road angle, to estimate the road angle torque component of the steering wheel torque. The steering control module also adjusts the steering wheel torque feedback in response to the road angle torque component.

[0009] A steering system for a vehicle includes an inertial measurement unit (IMU) configured to measure a first lateral acceleration of the vehicle. A torque sensor is configured to measure steering wheel torque. A steering control module is configured to receive the steering wheel torque and generate steering wheel torque feedback. A torque steering mitigation module is configured to determine a torque steering component of the steering wheel torque feedback in response to torque steering learning. A road angle detection module is configured to estimate a second lateral acceleration of the vehicle independently of the road angle on which the vehicle is traveling, and to selectively detect the road angle in response to a difference between the first measured lateral acceleration from the IMU and the second lateral acceleration being greater than a predetermined threshold. The torque steering mitigation module is further configured to perform at least one of the following: suspending torque steering learning in response to the road angle detection module detecting a road angle; and further estimating the second lateral acceleration based on a first lateral force on the front axle of the vehicle, a second lateral force on the rear axle of the vehicle, and the mass of the vehicle.

[0010] Among other features, torque steering learning utilizes a lookup table that outputs steering wheel torque indexed by the front axle torque. The road angle detection module estimates a second lateral force on the vehicle's rear axle based on yaw motion calculated by the IMU. The road angle detection module is also configured to calculate the lateral force corresponding to the road angle. The road angle detection module is configured to estimate the road angle torque component of the steering wheel torque.

[0011] Among other features, the road angle detection module uses a lookup table and a function, along with the road angle, to estimate the road angle torque component of the steering wheel torque. The steering control module also adjusts the steering wheel torque feedback in response to the road angle torque component.

[0012] Further areas of applicability of this disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0013] This invention also includes the following technical solutions:

[0014] 1. A steering system for a vehicle, comprising:

[0015] An inertial measurement unit (IMU) configured to measure the first lateral acceleration of the vehicle;

[0016] A torque sensor configured to measure steering wheel torque;

[0017] A steering control module configured to receive the steering wheel torque and generate steering wheel torque feedback;

[0018] A torque steering mitigation module configured to determine the torque steering component of the steering wheel torque feedback; and

[0019] A road angle detection module is configured to estimate the second lateral acceleration of the vehicle independently of the road angle on the road the vehicle is traveling on, and to selectively detect the road angle based on a first measured lateral acceleration from the IMU and the second lateral acceleration.

[0020] 2. The steering system according to Scheme 1, wherein the torque steering mitigation module determines the torque steering component in response to torque steering learning.

[0021] 3. The steering system according to Scheme 2, wherein the torque steering learning utilizes a lookup table, the lookup table outputting the steering wheel torque indexed by the front axle torque.

[0022] 4. The steering system according to Scheme 2, wherein the torque steering mitigation module is configured to selectively suspend the torque steering learning in response to the road angle detection module detecting the road angle.

[0023] 5. The steering system according to Scheme 1, wherein the road angle detection module is configured to estimate the second lateral acceleration based on a first lateral force on the front axle of the vehicle.

[0024] 6. The steering system according to Scheme 5, wherein the road angle detection module is further configured to estimate the second lateral acceleration based on the second lateral force on the rear axle of the vehicle.

[0025] 7. The steering system according to Scheme 6, wherein the road angle detection module estimates the second lateral force on the rear axle of the vehicle based on the yaw motion calculated in response to the IMU.

[0026] 8. The steering system according to claim 1, wherein the road angle detection module is configured to estimate the second lateral acceleration in response to a first lateral force on the front axle of the vehicle, a second lateral force on the rear axle of the vehicle, and the mass of the vehicle.

[0027] 9. The steering system according to Scheme 5, wherein the road angle detection module is further configured to detect when the vehicle is traveling at the road angle when the difference between the first measured lateral acceleration from the IMU and the second lateral acceleration is greater than a predetermined threshold.

[0028] 10. The steering system according to Scheme 1, wherein the road angle detection module is further configured to calculate the lateral force corresponding to the road angle.

[0029] 11. The steering system according to Scheme 1, wherein the road angle detection module is configured to estimate the road angle torque component of the steering wheel torque.

[0030] 12. The steering system according to claim 11, wherein the road angle detection module uses one of a lookup table and a function, along with the road angle, to estimate the road angle torque component of the steering wheel torque.

[0031] 13. The steering system according to claim 12, wherein the steering control module further adjusts the steering wheel torque feedback in response to the road angle torque component.

[0032] 14. A steering system for a vehicle, comprising:

[0033] An inertial measurement unit (IMU) configured to measure the first lateral acceleration of the vehicle;

[0034] A torque sensor configured to measure steering wheel torque;

[0035] A steering control module configured to receive the steering wheel torque and generate steering wheel torque feedback;

[0036] A torque steer mitigation module configured to determine the torque steer component of the steering wheel torque feedback in response to torque steer learning; and

[0037] A road angle detection module is configured to estimate the vehicle's second lateral acceleration independently of the road angle of the road the vehicle is traveling on, and to selectively detect the road angle in response to a first measured lateral acceleration from the IMU and the second lateral acceleration being greater than a predetermined threshold.

[0038] The torque steering mitigation module is further configured to implement at least one of the following:

[0039] The torque steering learning is paused in response to the road angle detection module detecting the road angle; and

[0040] The second lateral acceleration is also estimated based on the first lateral force on the front axle of the vehicle, the second lateral force on the rear axle of the vehicle, and the mass of the vehicle.

[0041] 15. The steering system according to Scheme 14, wherein the torque steering learning utilizes a lookup table, the lookup table outputting steering wheel torque indexed by the front axle torque.

[0042] 16. The steering system according to claim 15, wherein the road angle detection module estimates a second lateral force on the rear axle of the vehicle based on yaw motion calculated in response to the IMU.

[0043] 17. The steering system according to Scheme 15, wherein the road angle detection module is further configured to calculate the lateral force corresponding to the road angle.

[0044] 18. The steering system according to claim 15, wherein the road angle detection module is configured to estimate the road angle torque component of the steering wheel torque.

[0045] 19. The steering system according to claim 18, wherein the road angle detection module uses one of a lookup table and a function, along with the road angle, to estimate the road angle torque component of the steering wheel torque.

[0046] 20. The steering system according to claim 18, wherein the steering control module further adjusts the steering wheel torque feedback in response to the road angle torque component. Attached Figure Description

[0047] This disclosure will be more fully understood from the specific embodiments and accompanying drawings, in which:

[0048] Figure 1A The functional block diagram of an example hydraulic power steering (HPS) system according to this disclosure includes a controller having a torque steering mitigation module and a road angle detection module;

[0049] Figure 1B The present disclosure provides a functional block diagram of an example electronic power steering (EPS) system, which includes a controller having a torque steering mitigation module and a road angle detection module.

[0050] Figure 1C The functional block diagram of an example steer-by-wire (SBW) system according to this disclosure includes a controller having a torque steering mitigation module and a road angle detection module;

[0051] Figure 2 The illustration shows an example of a vehicle traveling on a flat road or an angled road with a non-zero road angle;

[0052] Figure 3 This is a flowchart illustrating an example of a method for adjusting torque steering feedback in response to the detection of a road angle, according to this disclosure; and

[0053] Figure 4 This is a flowchart illustrating an example of a method for adjusting torque steer mitigation in response to the detection of a road angle, according to the present disclosure.

[0054] In the accompanying drawings, reference numerals may be used repeatedly to identify similar and / or identical elements. Detailed Implementation

[0055] During acceleration of a vehicle with a driven front axle, the difference in torque between the left and right axles or the tire traction at the driven front axle can cause torque steer during acceleration. Torque steer pulls the steering wheel in one direction or the other, which can be frustrating for the driver. The vehicle may include a torque steer mitigation (TSM) module configured to reduce undesirable steering torque by causing torque feedback to be supplied to the steering wheel.

[0056] Vehicles can operate on roads with road angles (convex, angled, sloping, or cambered surfaces) to improve drainage and prevent water accumulation on the road surface. When the road is flat or concave, water accumulates on the road surface and can cause vehicle skidding and / or road damage. While angled roads reduce drainage-related problems, they introduce additional lateral forces on the vehicle due to its tilted mass.

[0057] Torque Steering Mitigation (TSM) modules may rely on a learning process that adjusts calibration coefficients or other parameters for a given vehicle during high front axle torque events. This learning process can adversely affect the TSM system when the vehicle accelerates or decelerates on angled roads, such as cambered roads. The road angle generates a steering torque component that can be incorrectly attributed to torque steer. Since cambered roads can also affect vehicle pull due to lateral forces in addition to torque steer caused by unbalanced longitudinal forces, the TSM learning function cannot operate properly if the effects of cambered and non-cambered roads are not distinguished. Therefore, one solution could be to pause learning once a cambered road is detected, while another solution could be to more comprehensively distinguish and subtract the effects of cambered roads on lateral / yaw deviations.

[0058] The vehicle includes a road angle detection module that uses one or more sensors (e.g., position and torque sensors) and rack force estimation to assess lateral road forces caused by varying road angles. In some examples, when traveling on a road camber, the road angle detection module causes the torque steering mitigation (TSM) module to temporarily pause the learning process. In other examples, the TSM module estimates the lateral forces at the front and rear axles based on rack force measurements and then calculates the lateral acceleration on the vehicle, excluding the torque effects caused by the road angle. In still other examples, the TSM module estimates the lateral force at the front axle based on front rack force measurements and estimates the lateral force at the rear axle based on yaw motion calculated by the IMU and the external yaw moment due to the torque vector, and then calculates the lateral acceleration on the vehicle, excluding the torque effects caused by the road angle.

[0059] By comparing the estimated lateral acceleration with the measured lateral acceleration from a sensor (e.g., an inertial measurement unit (IMU)), the estimated road camber angle can be detected, and the corresponding steering rack force feedback can be estimated. The torque steering mitigation (TSM) system adjusts the steering wheel torque feedback compensation based on the estimated road angle and the corresponding steering rack force.

[0060] For features such as torque steer mitigation, the calibration table or model uses the estimated equivalent road angle to generate steering torque feedback compensation. The steering torque feedback compensation, representing the steering feedback torque generated by the road, can then be subtracted from the measured total torque to produce an accurate estimate of the steering torque feedback caused by the axle torque requested by the driver.

[0061] Now for reference Figures 1A to 1CExamples of hydraulic, electronic, and steer-by-wire power steering systems are shown. While examples of these power steering systems are presented, other power steering system designs can be used. Figure 1A In this configuration, the steering mechanism 36 is a rack and pinion system, comprising a toothed rack (not shown) and a pinion (also not shown) located within rack and pinion housings 50 and 52. When the driver turns the steering wheel 26, the steering shaft 29 rotates the lower steering shaft 51, which is connected to the steering shaft 29 via a universal joint 34. The lower steering shaft 51 rotates the pinion. The rotation of the pinion moves the rack, which in turn moves the tie rod 38 connected to the steering knuckle 39 and the wheel (one side shown).

[0062] The hydraulic power steering system includes an actuator 60 that controls a pump 56 that pumps hydraulic fluid from a reservoir 58. The actuator 60 is connected to a variable assist actuator 64 via a hydraulic line 62. A hydraulic line 66 connects the variable assist actuator 64 back to the reservoir 58. The variable assist actuator 64 provides a variable hydraulic assist torque. Generally, the vehicle engine (not shown) rotates the pump 56. In response to a control signal on line 54, the actuator 60 selectively valves pressurized fluid from the pump 56 to the hydraulic line 62, thereby selectively controlling the hydraulic assist torque provided by the system. The hydraulic line 62 leads to the hydraulic assist actuator 64, which provides hydraulic power assistance to the steering system via the lower steering shaft 51. Hydraulic fluid output from the hydraulic assist actuator 64 returns to the reservoir 58 via the hydraulic line 66.

[0063] Torque adjuster 46 variably increases or decreases the steering system torque felt by the driver based on sensed torque steer. In some examples, torque adjuster 46 includes an electromagnetic device that generates an auxiliary or relative rotational force. Controller 16 controls torque adjuster 46 to add auxiliary torque or torque load to the steering system. An example of torque adjuster 46 is shown and described in commonly assigned U.S. Patent No. 4,871,040, which is incorporated herein by reference.

[0064] In some examples, vehicle speed signal 14 is input to controller 16, and sensor 21 provides steering wheel position signal and / or steering wheel torque signal to controller 16. Controller 16 also uses steering wheel speed information, which it can determine by integrating the steering wheel position signal. In some examples, in addition to a torque sensor, sensor 21 may also include an optically coded sensor, a variable resistance sensor, or any other suitable type of position sensor.

[0065] During operation, when the driver drives the vehicle and turns the steering wheel, the controller 16 senses the vehicle speed, steering wheel position, steering wheel torque, and / or steering wheel speed. The controller 16 generates commands for both the torque adjuster 46 and the actuator 60. By controlling the flow of hydraulic fluid through the actuator 60 to the hydraulic line 62, the controller 16 indirectly controls the pump 56, which automatically opens and closes in response to fluid pressure in the reservoir 58. The controller 16 controls the actuator 60 such that, during normal driving conditions, a relatively constant low flow of hydraulic fluid is provided to the hydraulically assisted actuator 64 through the hydraulic line 62. The flow of hydraulic fluid to the actuator 64 increases in response to high steering wheel speeds or lateral acceleration maneuvers. The torque adjuster 46 provides the difference between the torque assistance provided to the actuator at a constant flow rate and the torque assistance required by the vehicle driver, thereby offsetting or adding torque to the variable auxiliary actuator 64.

[0066] Controller 16 includes a torque steering mitigation module 84 that estimates torque steering feedback. In some examples, the torque steering mitigation module 84 uses a learning process to adjust its operation. The torque steering feedback is output to a hydraulic power steering module 82, which adjusts the operation of the torque adjuster 46.

[0067] The road angle detection module 86, further described below, detects when the vehicle is traveling at a road angle and selectively disables the learning of the torque steering module and / or provides road angle torque feedback to the hydraulic power steering module 82.

[0068] exist Figure 1B In this configuration, the input of the electric power steering (EPS) motor 90 is connected to the steering shaft 29. The output of the EPS motor 90 is connected to the steering shaft 91, which drives the pinion gear. The EPS motor 90 changes torque assistance in response to the EPS module 88, the torque steering mitigation module 84, and the road angle detection module 86, as will be further described below.

[0069] exist Figure 1C In this configuration, sensor 110 senses the angular position and torque of steering wheel 26. Steering wheel motor 112 is configured to provide steering feedback to steering wheel 26 to provide road feel. Controller 16 is configured to control road wheel angle (RWA) motor 118, which is configured to adjust the wheel angles. Steering wheel motor 112 responds to steer-by-wire (SBW) module 114, torque steering mitigation module 84, and road angle detection module 86 by changing torque assistance, as will be further described below. The output of RWA motor 118 is connected to steering shaft 120, which drives a pinion gear.

[0070] In the first step, the road angle detection module 86 detects the road angle. In some examples, to eliminate or reduce the influence of the road angle on the lateral force estimation, the lateral force estimation is based on the rack force in the front axle.

[0071]

[0072] The calculation can be performed as follows: and N fx :

[0073]

[0074] and

[0075]

[0076] Where L is the steering arm, F r It is rack force, r kp It is the offset of the steering axis from the tire in the lateral direction, R nom X is the nominal tire radius, γ is the kingpin inclination angle, and τ is the camber angle. f and X r These are the vehicle wheelbases from the center of gravity (CG) to the front and rear axles, respectively. m represents the vehicle's unsprung mass, and Z... g This indicates the height of the vehicle's center of gravity (CG). g represents the gravity coefficient. a x and a y These are longitudinal acceleration and lateral acceleration. δ f It refers to the front tire steering angle. L f It refers to the track width of the front axle. It is the total drag torque generated around the steering z-axis. It is the total drag generated around the steering z-axis. N fx It is the nominal tire force.

[0077] In some examples, the following is based on yaw motion calculated by IMU 70. The lateral forces in the rear axle of the vehicle are estimated by considering the external yaw moment caused by the torque vectoring device.

[0078] and

[0079]

[0080] Where T M It is the traction force, L1 is the length of the front axle, F yf L2 is the front lateral tire force, L2 is the rear axle length, and F is the rear axle length. yr It is the rear lateral tire force, and It is a lateral motion.

[0081] Lateral acceleration can be estimated by estimating the lateral forces in the front and rear axles as follows.

[0082]

[0083] The following compares this lateral acceleration with the lateral acceleration measured by the IMU 70: If the estimated acceleration is Measured lateral acceleration If the difference exceeds a predetermined threshold T, it can be concluded that the vehicle experiences a road angle. The effect of road angle on lateral force is calculated as follows:

[0084]

[0085] Therefore, usually

[0086] In one approach, torque steering learning is paused when the vehicle experiences a road angle. In another approach, compensation is calculated for the impact of road angle on lateral motion and steering torque feedback.

[0087] Perform steering wheel torque calculation. A calibration table can be used to map the estimated (road camber) angle to steering wheel torque. In some examples, the torque feedback changes more gradually at smaller road camber angles and more drastically at larger road camber angles; or, differently, this depends on how the system is calibrated. Therefore, T steering,feedback =T meas -T steering,road or ), where T meas It is the measured steering torque, and T steering，road It is the estimated steering wheel torque generated by the road.

[0088] Then, torque steer mitigation modifications are implemented. The calculated steering torque feedback T is used in the TSM calculation. steering，feedback .

[0089] Now for reference Figure 3This illustrates a first method for implementing torque steer mitigation according to the present disclosure. At 210, the method determines whether activation conditions are met. In some examples, activation conditions include roll motion being less than a predetermined value and crosswind being less than a predetermined value. An example of roll motion detection can be found in the article “Estimation of land vehicle roll and pitch angles” by Eric Tseng, H., Xu, L. and Hrovat, D. (2007) in the journal Vehicle System Dynamics, 45(5), pp. 433–443, which is hereby incorporated herein by reference in its entirety. Examples of crosswind detection can be found in U.S. Patent No. 9,102,333, entitled "Enhanced Crosswind Estimation," published August 11, 2015, and U.S. Patent No. 11,479,308, entitled "Active Vehicle Interface for Crosswind Management," published October 25, 2022, which are hereby incorporated herein by reference in their entirety.

[0090] At 214, the method estimates lateral force and lateral acceleration. At 218, the method detects and estimates the road angle. At 222, the method determines whether the vehicle is on a road oriented at an angle. If 222 is false, the method continues torque steer mitigation and learning at 224. If 222 is true, the method pauses torque steer mitigation learning at 226. At 228, when the vehicle is traveling on a road at an angle, the method calculates torque steer mitigation without torque steer mitigation learning.

[0091] Now for reference Figure 4 This illustrates another method for implementing torque steer mitigation according to the present disclosure. At 310, the method determines whether an activation condition is met. At 314, the method estimates lateral forces and lateral accelerations. At 318, the method detects and estimates a road angle. At 322, the method determines whether a road angle (e.g., corresponding to a road camber that causes steering torque) is detected. If 322 is false, the method continues with torque steer mitigation at 324. If 322 is true, the method calculates steering wheel torque based on the estimated road angle at 326. At 328, the method subtracts the estimated steering wheel torque caused by the road angle from the measured torque at the steering wheel. At 332, the method calculates torque steer mitigation.

[0092] The foregoing description is illustrative in nature and is not intended to limit this disclosure, its application, or use in any way. The broad teachings of this disclosure can be implemented in various forms. Therefore, although this disclosure includes specific examples, its true scope should not be so limited, as other modifications will become apparent upon examination of the drawings, specification, and the following claims. It should be understood that one or more steps within the method can be performed in different orders (or simultaneously) without altering the principles of this disclosure. Furthermore, although each of the embodiments described above is described as having certain features, any one or more of those features described with respect to any embodiment of this disclosure can be implemented and / or combined with features of any of the embodiments in other embodiments, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more embodiments with each other remains within the scope of this disclosure.

[0093] Various terms (including “connection,” “joint,” “link,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “set up”) are used to describe spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.). Unless explicitly described as “direct,” when describing the relationship between a first element and a second element in the foregoing disclosure, the relationship can be a direct relationship where no other intervening element exists between the first and second elements, or an indirect relationship where one or more intervening elements exist (spatially or functionally) between the first and second elements. As used herein, the phrases A, B, and C, at least one of which should be interpreted as referring to the logic (A OR B OR C) using non-exclusive logic OR, and should not be interpreted as referring to “at least one of A, at least one of B, and at least one of C.”

[0094] In the diagram, as indicated by the arrowheads, the direction of the arrows generally illustrates the flow of information (such as data or instructions) of interest to the diagram. For example, when components A and B exchange various types of information, but the information transmitted from component A to component B is relevant to the diagram, the arrow can point from component A to component B. This unidirectional arrow does not imply that no other information is transmitted from component B to component A. Furthermore, for information sent from component A to component B, component B can send a request for or confirmation of receipt of that information to component A.

[0095] In this application (including the following limitations), the term "module" or "controller" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include: Application Specific Integrated Circuit (ASIC); digital, analog, or mixed-signal analog / digital discrete circuit; digital, analog, or mixed-signal analog / digital integrated circuit; combinational logic circuit; Field Programmable Gate Array (FPGA); processor circuitry (shared, dedicated, or grouped) that executes code; memory circuitry (shared, dedicated, or grouped) that stores code executed by the processor circuitry; other suitable hardware components that provide the described functionality; or combinations of some or all of the above, such as in a system-on-a-chip.

[0096] A module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functionality of any given module disclosed herein may be distributed among multiple modules connected via the interface circuits. For example, multiple modules may allow for load balancing. In another example, a server (also referred to as a remote or cloud) module may perform some functions on behalf of a client module.

[0097] The term "code" as used above can include software, firmware, and / or microcode, and can refer to programs, routines, functions, classes, data structures, and / or objects. The term "shared processor circuitry" covers a single processor circuitry that executes some or all of the code from multiple modules. The term "group processor circuitry" covers a processor circuitry that, in combination with additional processor circuitry, executes some or all of the code from one or more modules. References to multiple processor circuitry cover multiple processor circuitry on a discrete die, multiple processor circuitry on a single die, multiple cores of a single processor circuitry, multiple threads of a single processor circuitry, or a combination of the above. The term "shared memory circuitry" covers a single memory circuitry that stores some or all of the code from multiple modules. The term "group memory circuitry" covers a memory circuitry that, in combination with additional memory, stores some or all of the code from one or more modules.

[0098] The term memory circuit is a subset of the term computer-readable medium. As used herein, the term computer-readable medium does not cover transient electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); therefore, the term computer-readable medium can be considered tangible and non-transient. Non-limiting examples of non-transient, tangible computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital magnetic tape or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs).

[0099] The apparatus and methods described in this application can be implemented, in part or in whole, by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in a computer program. The function blocks, flowchart components, and other elements described above serve as software specifications that can be routinely translated into a computer program by a skilled technician or programmer.

[0100] A computer program includes processor-executable instructions stored on at least one non-transitory, tangible, computer-readable medium. A computer program may also include or depend on stored data. A computer program may encompass a basic input / output system (BIOS) that interacts with the hardware of a special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0101] Computer programs may include: (i) descriptive text to be parsed, such as HTML (Hypertext Markup Language), XML (Extensible Markup Language), or JSON (JavaScript Object Annotation); (ii) assembly code; (iii) object code generated from source code by a compiler; (iv) source code for execution by an interpreter; and (v) source code for compilation and execution by a just-in-time (JIT) compiler, etc. As an example only, source code can be written using syntax from languages ​​including: C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, etc. Fortran, Perl, Pascal, Curl, OCaml, HTML5 (Hypertext Markup Language 5th Edition), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK and

Claims

1. A steering system for a vehicle, comprising: An inertial measurement unit (IMU) configured to measure the first lateral acceleration of the vehicle; A torque sensor configured to measure steering wheel torque; A steering control module configured to receive the steering wheel torque and generate steering wheel torque feedback; A torque steering mitigation module configured to determine the torque steering component of the steering wheel torque feedback; as well as A road angle detection module is configured to estimate the second lateral acceleration of the vehicle independently of the road angle on the road the vehicle is traveling on, and to selectively detect the road angle based on a first measured lateral acceleration from the IMU and the second lateral acceleration.

2. The steering system according to claim 1, wherein, The torque steering mitigation module determines the torque steering component in response to torque steering learning.

3. The steering system according to claim 2, wherein, The torque steering learning utilizes a lookup table, which outputs the steering wheel torque indexed by the front axle torque.

4. The steering system according to claim 2, wherein, The torque steering mitigation module is configured to selectively pause torque steering learning in response to the road angle detection module detecting the road angle.

5. The steering system according to claim 1, wherein, The road angle detection module is configured to estimate the second lateral acceleration based on a first lateral force on the front axle of the vehicle.

6. The steering system according to claim 5, wherein, The road angle detection module is also configured to estimate the second lateral acceleration based on the second lateral force on the rear axle of the vehicle.

7. The steering system according to claim 6, wherein, The road angle detection module estimates the second lateral force on the rear axle of the vehicle based on the yaw motion calculated by the IMU.

8. The steering system according to claim 1, wherein, The road angle detection module is configured to estimate the second lateral acceleration in response to a first lateral force on the front axle of the vehicle, a second lateral force on the rear axle of the vehicle, and the mass of the vehicle.

9. The steering system according to claim 5, wherein, The road angle detection module is also configured to detect when the vehicle is traveling at the road angle when the difference between the first measured lateral acceleration from the IMU and the second lateral acceleration is greater than a predetermined threshold.

10. The steering system according to claim 1, wherein, The road angle detection module is also configured to calculate the lateral force corresponding to the road angle.

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