Steering force lag adjustment for steer-by-wire and closed-loop electric power steering

Abstract

A method for performing lag adjustment in a steer-by-wire (SbW) steering system of a vehicle includes determining a desired lag associated with rotating a steering wheel of the vehicle; determining, based on the desired lag, whether to perform a lag decrease or an execution lag increase; in response to determining to perform hysteresis reduction, calculating a hysteresis reduction value, modifying an estimated rack load based on the hysteresis reduction value, and generating a reference torque based on the estimated rack load modified according to the hysteresis reduction value; in response to determining to perform a hysteresis increase, calculating a hysteresis increase, and generating the reference torque based on the hysteresis increase; and controlling the steering wheel based on the reference torque.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 534,392, filed on August 24, 2023. The entire disclosures of the above-referenced applications are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to controlling components in electric power steering (EPS) and steer-by-wire (SbW) steering systems. Background Art

[0004] Vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, airplanes, all-terrain vehicles, RVs, or other suitable forms of transportation) typically include a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) steering system, a hydraulic steering system, or other suitable steering system. The steering system of such a vehicle typically controls various aspects of the vehicle's steering, including providing steering assistance to the operator of the vehicle, controlling the vehicle's steerable wheels, etc. Summary of the invention

[0005] The present disclosure generally relates to control of a steer-by-wire (SbW) steering system.

[0006] One aspect of the disclosed embodiment includes a method for performing hysteresis shaping in a steer-by-wire (SbW) steering system of a vehicle. The method includes: determining an expected hysteresis associated with rotating a steering wheel of the vehicle; determining whether to perform hysteresis reduction or hysteresis increase based on the expected hysteresis; in response to determining to perform hysteresis reduction, calculating a hysteresis reduction value, modifying an estimated rack load based on the hysteresis reduction value, and generating a reference torque based on the estimated rack load modified according to the hysteresis reduction value; in response to determining to perform hysteresis increase, calculating a hysteresis increase value, and generating the reference torque based on the hysteresis increase value; and controlling the steering wheel based on the reference torque.

[0007] Other areas of applicability of the present 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 the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, in accordance with conventional practice, the various features of the drawings are not drawn to scale. Instead, the sizes of the various features are arbitrarily enlarged or reduced for clarity.

[0009] Figure 1AA vehicle according to the principles of the present disclosure is generally illustrated.

[0010] Figure 1B A controller according to the principles of the present disclosure is generally illustrated.

[0011] Figure 2A An example rack or RWA controller and column or handwheel actuator (HWA) controller of a steering system configured to implement hysteresis adjustment techniques in accordance with the principles of the present disclosure are generally illustrated.

[0012] Figure 2B An example reference torque calculator configured to implement a hysteresis adjustment technique in accordance with the principles of the present disclosure is illustrated.

[0013] Figure 3 is a flow chart generally illustrating a method of performing hysteresis adjustment according to the principles of the present disclosure. DETAILED DESCRIPTION

[0014] The following discussion is directed to various embodiments of the present disclosure. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used to limit the scope of the present disclosure (including the claims). In addition, it will be understood by those skilled in the art that the following description has a wide range of applications, and the discussion of any embodiment is only meant as an example of that embodiment, and is not intended to imply that the scope of the present disclosure (including the claims) is limited to that embodiment.

[0015] As described, a vehicle (such as a car, truck, sport utility vehicle, crossover, minivan, boat, airplane, all-terrain vehicle, RV, or other suitable form of transportation) typically includes a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) steering system, a hydraulic steering system, or other suitable steering system. The steering system of such a vehicle typically controls various aspects of the vehicle's steering, including providing steering assistance to the operator of the vehicle, controlling the vehicle's steerable wheels, etc.

[0016] Steering systems require hysteresis in the steering effort curve in order to provide a "natural" feel to the driver. Too little hysteresis will make the system feel lighter, while too much hysteresis will make the system feel higher in friction. In connected steering systems (hydraulic power steering (HPS) systems, electric power steering (EPS) systems, etc.), the overall system hysteresis is usually higher than the desired hysteresis due to the friction of all components involved (both vehicle chassis components and steering system components). In SbW applications where the effort depends on the measured steering system rack force, the hysteresis is determined by the friction component of the estimated rack force. The hysteresis can be greater or less than the desired hysteresis.

[0017] Therefore, methods to increase or decrease force application hysteresis are needed for SbW and closed-loop EPS applications. The hysteresis adjustment system and method according to the present disclosure implements techniques for applying hysteresis addition or augmentation (increase) and hysteresis compensation or reduction (reduction) to SbW and closed-loop EPS systems.

[0018] Figure 1A A vehicle 10 in accordance with the principles of the present disclosure is generally illustrated. The vehicle 10 may include any suitable vehicle, such as a car, a truck, a sport utility vehicle, a minivan, a crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although the vehicle 10 is illustrated as a passenger vehicle having wheels and for use on roads, the principles of the present disclosure may be applied to other vehicles, such as airplanes, boats, trains, drones, or other suitable vehicles.

[0019] The vehicle 10 includes a vehicle body 12 and a hood 14. A passenger compartment 18 is at least partially defined by the vehicle body 12. Another portion of the vehicle body 12 defines an engine compartment 20. The hood 14 may be removably attached to a portion of the vehicle body 12 such that when the hood 14 is in a first position or an open position, the hood 14 provides access to the engine compartment 20, and when the hood 14 is in a second position or a closed position, the hood 14 covers the engine compartment 20. In some embodiments, the engine compartment 20 may be disposed at the rear of the vehicle 10, rather than in the generally illustrated location.

[0020] The passenger compartment 18 may be disposed rearward of the engine compartment 20, but in embodiments where the engine compartment 20 is disposed at the rear of the vehicle 10, the passenger compartment 18 may be disposed forward of the engine compartment 20. The vehicle 10 may include any suitable propulsion system including an internal combustion engine, one or more electric motors (e.g., an electric vehicle), one or more fuel cells, a hybrid (e.g., a hybrid vehicle) propulsion system including a combination of an internal combustion engine, one or more electric motors, and / or any other suitable propulsion system.

[0021] In some embodiments, the vehicle 10 may include a gasoline fuel engine, such as a spark ignition engine. In some embodiments, the vehicle 10 may include a diesel fuel engine, such as a compression ignition engine. The engine compartment 20 accommodates and / or encloses at least some components of the propulsion system of the vehicle 10. In addition or alternatively, propulsion controls (such as accelerator actuators (e.g., accelerator pedals), brake actuators (e.g., brake pedals), steering wheels, and other such components) are disposed in the passenger compartment 18 of the vehicle 10. The propulsion controls may be actuated or controlled by an operator of the vehicle 10, and may be directly connected to corresponding components of the propulsion system, such as throttles, brakes, vehicle shafts, vehicle transmissions, etc., respectively. In some embodiments, the propulsion controls may transmit signals to a vehicle computer (e.g., drive-by-wire), which in turn may control corresponding propulsion components of the propulsion system. Therefore, in some embodiments, the vehicle 10 may be an autonomous vehicle.

[0022] In some embodiments, the vehicle 10 includes a transmission connected to the crankshaft via a flywheel or a clutch or a fluid coupling. In some embodiments, the transmission includes a manual transmission. In some embodiments, the transmission includes an automatic transmission. In the case of an internal combustion engine or a hybrid vehicle, the vehicle 10 may include one or more pistons that operate in conjunction with the crankshaft to generate a force that is transmitted through the transmission to one or more shafts that rotate the wheels 22. When the vehicle 10 includes one or more electric motors, the vehicle battery and / or fuel cell provides energy to the electric motors to rotate the wheels 22.

[0023] The vehicle 10 may include an automatic vehicle propulsion system, such as cruise control, adaptive cruise control, automatic braking control, other automatic vehicle propulsion systems, or combinations thereof. The vehicle 10 may be an autonomous or semi-autonomous vehicle, or other suitable type of vehicle. The vehicle 10 may include more or fewer features than those generally illustrated and / or disclosed herein.

[0024] In some embodiments, the vehicle 10 may include an Ethernet component 24, a controller area network (CAN) bus 26, a media oriented system transport component (MOST) 28, a FlexRay component 30 (e.g., a wire control brake system, etc.), and a local interconnect network component (LIN) 32. The vehicle 10 may use the CAN bus 26, the MOST 28, the FlexRay component 30, the LIN 32, other suitable networks or communication systems, or a combination thereof to transmit various information from sensors, such as those inside or outside the vehicle, to various processors or controllers, such as those inside or outside the vehicle. The vehicle 10 may include more or fewer features than those generally illustrated and / or disclosed herein.

[0025] In some embodiments, the vehicle 10 may include a steering system, such as an EPS system, a steer-by-wire steering system (e.g., which may include or communicate with one or more controllers that control components of the steering system without using a mechanical connection between a steering wheel and the wheels 22 of the vehicle 10), a hydraulic steering system (e.g., which may include a magnetic actuator incorporated into a valve assembly of the hydraulic steering system), or other suitable steering systems.

[0026] The steering system may include an open-loop feedback control system or mechanism, a closed-loop feedback control system or mechanism, or a combination thereof. The steering system may be configured to receive various inputs, including but not limited to steering wheel position, input torque, one or more wheel positions, other suitable inputs or information, or a combination thereof.

[0027] Additionally or alternatively, the input may include steering wheel torque, steering wheel angle, motor speed, vehicle speed, estimated motor torque command, other suitable inputs, or combinations thereof. The steering system may be configured to provide steering functionality and / or control to the vehicle 10. For example, the steering system may generate an assist torque based on various inputs. The steering system may be configured to selectively control the motor of the steering system using the assist torque to provide steering assistance to the operator of the vehicle 10. The steering system of the present disclosure is configured to implement hysteresis adjustment, as described in more detail below.

[0028] In some embodiments, vehicle 10 includes one or more controllers, such as Figure 1B1. The controller 100 generally illustrated in FIG. 1. The controller 100 may correspond to a steering system controller. The controller 100 may include any suitable controller, such as an electronic control unit or other suitable controller. The controller 100 may be configured to control various functions of, for example, a steering system and / or various functions of the vehicle 10. The controller 100 may include a processor 102 and a memory 104. The processor 102 may include any suitable processor, such as the processor described herein. In addition, or alternatively, in addition to or different from the processor 102, the controller 100 may include any suitable number of processors. The memory 104 may include a single disk or multiple disks (e.g., a hard disk drive), and include a storage management module that manages one or more partitions within the memory 104. In some embodiments, the memory 104 may include flash memory, semiconductor (solid-state) memory, etc. The memory 104 may include a random access memory (RAM), a read-only memory (ROM), or a combination thereof. The memory 104 may include instructions that, when executed by the processor 102, cause the processor 102 to control at least various aspects of the vehicle 10. Additionally, or alternatively, memory 104 may include instructions that, when executed by processor 102, cause processor 102 to perform functions associated with the systems and methods described herein.

[0029] The controller 100 may receive one or more signals indicating sensed or measured characteristics of the vehicle 10 from various measurement devices or sensors 106. The sensors 106 may include any suitable sensors, measurement devices, and / or other suitable mechanisms. For example, the sensors 106 may include one or more torque sensors or devices, one or more steering wheel position sensors or devices, one or more motor position sensors or devices, one or more position sensors or devices, other suitable sensors or devices, or combinations thereof. The one or more signals may indicate steering wheel torque, steering wheel angle, motor speed, vehicle speed, other suitable information, or combinations thereof.

[0030] As used herein, a "controller" may refer to a hardware module or component including one or more processors or microcontrollers, memory, sensors, one or more actuators, communication interfaces, etc., any portion of which may be collectively referred to as a "circuit". As described herein, the corresponding functions and steps performed by a given controller, control circuit, etc. may be performed by multiple controllers, processors, etc. in common. For example, a processor, processing device, controller, control circuit, etc. that is "configured to execute" may refer to a single processor, processing device, controller, etc. that is configured to execute both A and B, or may refer to a first processor, processing device, controller, etc. that is configured to execute A and a second processor, processing device, controller, etc. that is configured to execute B. For simplicity, a "control circuit configured to execute A and B" may refer to a single or multiple processors, processing devices, controllers, etc. that are collectively configured to execute A and B.

[0031] In some embodiments, the controller 100 may perform the methods described herein. However, the methods described herein as performed by the controller 100 are not meant to be limiting, and any type of software executed on a controller, processor, or other circuit may implement the hysteresis adjustment techniques as described herein without departing from the scope of the present disclosure. For example, a controller such as a processor executing software within a computing device may implement the systems and methods described herein.

[0032] The hysteresis adjustment system and method according to the present disclosure is configured to provide a hysteresis adjustment to the SbW and closed loop EPS systems (such as those described above in Figure 1A and Figure 1B The EPS system implemented by the vehicle 10 and controller 100 described in the drawings) applies hysteresis addition or increase (increase) and hysteresis compensation or reduction (decrease).

[0033] Figure 2A An example rack or RWA controller 200 and column or steering wheel actuator (HWA) controller 204 of a steering system configured to implement hysteresis adjustment techniques according to the present disclosure are illustrated. For example, the HWA controller 204 is configured to generate a steering wheel actuator (HWA) motor torque command based on an estimated rack force (e.g., an estimated rack force signal) and one or more other input signals (e.g., vehicle speed, steering wheel position, and steering wheel speed) received from the RWA controller 200. The RWA controller 200 is configured to determine the estimated rack force based on the motor torque required to achieve or maintain an actual rack position. The controllers 200 and 204 may correspond to, be implemented by, or the like, one or more steering system controllers.

[0034] As an example, the HWA controller 204 includes a reference torque calculator 208 configured to calculate a reference torque (T ) based on the estimated rack force and one or more other input signals.ref ). For example, the reference torque corresponds to the sum of various inputs / measurements (such as applied force, hysteresis, self-alignment correction, damping, catch mechanism, etc.). A closed-loop (e.g., PID closed-loop) torque controller 212 is configured to generate and output a motor torque command based at least in part on a force or torque applied by the driver (e.g., “Tbar torque”) and a reference torque. The motor torque command is provided as a control signal to control the motor of the steering wheel actuator.

[0035] The estimated rack force corresponds to the measured or estimated wheel actuator motor torque.Thus, the estimated rack force (and any estimated rack force offset or error) is a key factor for determining the force provided by the motor of the steering wheel actuator.

[0036] In some examples, the HWA controller 204 may also include a C-factor lookup module 216 and a rack position reference calculator 220. For example, the rack position reference calculator 220 is configured to generate a rack position reference based on the C-factor received from the C-factor lookup module 216. The C-factor may be determined based on a steering wheel angle ("HwAg") corresponding to a driver input (e.g., a steering wheel angle indicating a driver's intent communicated via the steering wheel). Example systems and methods for obtaining a rack position reference and a C-factor are described in more detail in U.S. patent application Ser. No. 18 / 318,657, filed May 16, 2023, the entire contents of which are incorporated herein by reference.

[0037] The RWA controller 200 includes a rack position controller 224 (e.g., a PID rack position controller) that is configured to generate one or more rack position control signals based on an actual rack position and a rack position reference (e.g., based on a difference between the actual rack position and the rack position reference). For example, the rack position control signals may include, but are not limited to, rack motor speed and motor torque command (e.g., indicating the amount of torque applied by the driver) signals. In this manner, the rack position is controlled to follow the driver's intent (as indicated by the rack reference position).

[0038] The rack force predictor 228 generates an estimated rack force based on the output of the rack position controller 224 (e.g., based on a function of the rack motor speed, the rack motor torque command, etc.). In various examples, the estimated rack force can be calculated based on the amount of torque applied to the steering wheel by the driver (as indicated by the rack motor torque command, various sensor signals, etc.). As shown, the rack force predictor 228 can output the estimated rack force, and the reference torque calculator 208 (and / or another component of the RWA controller 200, the HWA controller 204, etc.) can obtain an estimated rack load based on the estimated rack force. In other examples, the rack force predictor 228 can output an estimated rack load. In some cases, the terms "estimated rack force" and "estimated rack load" can be used interchangeably.

[0039] For example, for RWA position control, a rack position reference signal ("RackPosRef") may be calculated based on a position error ("PosErr") between an ADAS rack position reference value or signal ("ADASRackPosRef") and an HWA rack position reference value or signal ("HWARackPosRef"). Conversely, HWA position control is based on a position error between the HWA position and the RWA position, so that the steering wheel may be controlled to rotate in a manner consistent with the rotation of the wheel in a hands-off state.

[0040] The reference torque may correspond to a desired torque, ideal torque, or target torque that the driver (i.e., at the steering wheel / steering wheel) will feel. As described above, the reference torque is calculated based on inputs including, but not limited to, driver input (e.g., input torque corresponding to the angle at which the steering wheel is turned), road conditions, damping, hysteresis, etc. The torque at the steering wheel is controlled (e.g., via HWA) to match the reference torque. For example, the output of one or more sensors measuring the actual torque at the wheels is used to minimize the difference between the reference torque and the actual torque.

[0041] In a steering system, hysteresis corresponds to the vertical distance between the clockwise and counterclockwise directions in a graph of steering wheel torque vs. steering wheel angle (or steering wheel torque vs. rack force). For example, steering wheel torque and steering wheel angle data measured in a vehicle can be collected and used to create a graph of steering wheel torque vs. steering wheel angle. The vertical separation between the clockwise and counterclockwise directions will be the amount of hysteresis felt by the driver. There is generally an ideal amount of hysteresis that provides a good steering feel to the driver. Using the methods described herein, hysteresis can be adjusted to provide this ideal curve to the driver in a vehicle using a closed-loop steering wheel torque control steering system.

[0042] The force function (e.g., the force function implemented by the reference torque calculator 208) defines the relationship between the driver input (e.g., the force or torque applied by the driver to the steering wheel, which may be referred to as the "force") and the response (i.e., movement) of the steering system. For example, the force function may output a force value based on a lookup table or other function (e.g., by using an estimated rack load as an input). The estimated rack load may be modified by adding a calculated return load value to the estimated rack load before being input into the lookup table.

[0043] The effort function indicates the amount of effort required by the driver to cause the desired response. Therefore, the steering system requires hysteresis in the steering effort curve to provide a "natural" feel to the driver. In an SbW system, the effort depends on the measured or estimated steering system rack force. Therefore, the hysteresis is determined based on the friction component of the estimated rack force. However, the hysteresis determined in this way can be greater or less than the desired hysteresis.

[0044] Systems and methods according to the present invention are configured to implement hysteresis adjustment techniques to selectively adjust (eg, increase or decrease) hysteresis to more accurately achieve a desired hysteresis. For example, the reference torque calculator 208 may be configured to implement hysteresis adjustment as described in more detail below.

[0045] Figure 2B An example implementation of a reference torque calculator 208 including a hysteresis adjustment module 240 according to the present disclosure is shown. As shown, an estimated rack load is input to a force function 244. The force function 244 may output a force value based on a lookup table or other function (e.g., by using the estimated rack load as an input). In some examples, the estimated rack load may be modified by adding a rack / reset load value to the estimated rack load before being input to the lookup table. For example, a rack load estimator 248 may be configured to estimate or calculate an estimated rack load, which is then adjusted by adding a rack / reset load value to the estimated rack load (e.g., at an adder 252) before being input to the lookup table of the force function 244. In one example, the rack load estimator 248 estimates the rack load based on one or more sensor inputs and / or calculated or modeled values ​​(e.g., rack force deadband value, understeer rack force estimate, estimated rack force, etc.). In some examples, the rack load may be measured rather than estimated.

[0046] The hysteresis adjustment module 240 is configured to independently perform hysteresis addition / increase and hysteresis reduction / compensation / reduction. For example, when looking at a graph of steering effort vs. rack load, increasing the effort hysteresis requires shifting the effort curve along the effort axis. Therefore, to achieve this shift along the effort axis, an additional hysteresis torque is added to the reference torque simulated by the HWA. Figure 2BAs shown, the force value calculated / output by the force function 244 corresponds to the desired force value. The hysteresis adjustment module 240 calculates a hysteresis increase value (which may be a positive or negative value) to be added to the desired force value. Therefore, the reference torque output by the reference torque calculator 208 is modified / shifted according to the hysteresis increase value. The hysteresis increase value may be calculated based on one or more inputs including, but not limited to, damping, end-of-stroke force, etc.

[0047] On the contrary, when viewing the diagram of steering force vs. rack load, reducing the force hysteresis requires shifting the force curve along the rack load axis. Therefore, in order to achieve this shift along the rack load axis, the estimated rack load input to the force function 244 is shifted before being input to the force function 244. For example, as shown in the figure, the hysteresis adjustment module 240 calculates a hysteresis reduction value, which is added to the estimated rack load. Therefore, the adjusted estimated rack load provided to the force function 244 is modified / shifted according to the hysteresis reduction value. The hysteresis increase value can be calculated based on one or more inputs including but not limited to return, damping, hysteresis compensation, etc.

[0048] In this way, the desired force applied to the SbW (and closed loop EPS) system is modified to allow for an increase and / or decrease in the desired hysteresis experienced by the driver. Figure 2B Separate hysteresis increase and decrease methods are implemented as described in . This involves modifying the rack force input to the force application function to allow for hysteresis reduction, and involves directly modifying the desired force application to allow for hysteresis increase.

[0049] Figure 3 is a flowchart generally illustrating a method 300 for performing hysteresis adjustment according to the principles of the present disclosure. For example, one or more computing devices, processors, or processing devices, etc. are configured to execute instructions to implement the method 300, such as one or more processors in the processors of the system described herein (e.g., a computing device or processor of a vehicle configured to implement the controller 100, the reference torque calculator 208, etc.). In some examples, one or more of the steps of the method 300 described below may be skipped or omitted, and / or one or more of the steps may be performed in an order different from the order described.

[0050] At 304 , method 300 includes receiving one or more inputs associated with controlling a steering wheel actuator of a vehicle, such as input associated with calculating a reference torque. The one or more inputs may include, but are not limited to, an estimated rack force, an estimated rack load, and the like.

[0051] At 308, the method 300 includes determining whether to perform a hysteresis reduction or a hysteresis increase. For example, a desired hysteresis is calculated based on various inputs (e.g., measured values, sensed values, and / or calculated values). Based on the desired hysteresis, it is determined whether to perform a hysteresis reduction (i.e., reduce the hysteresis to achieve the desired hysteresis) or a hysteresis increase (i.e., increase the hysteresis to achieve the desired hysteresis). To perform a hysteresis reduction, the method 300 continues to 312. To perform a hysteresis increase, the method 300 continues to 316.

[0052] At 312, the method 300 includes calculating a hysteresis reduction value. At 320, the method 300 includes combining the hysteresis reduction value with the estimated rack load to obtain an adjusted estimated rack load. At 324, the method 300 includes obtaining an applied force value based on the adjusted estimated rack load. At 328, the method 300 includes outputting a reference torque based on the applied force value.

[0053] At 316, the method 300 includes calculating a hysteresis increase value. At 332, the method 300 includes obtaining a force value based on the adjusted estimated rack load. At 336, the method 300 includes modifying the force value based on the hysteresis increase value (e.g., by adding the hysteresis increase value to the force value). At 340, the method 300 includes outputting a reference torque based on the modified force value (i.e., the force value as modified by the hysteresis increase value).

[0054] The above discussion is intended to illustrate the principles and various embodiments of the present invention. Once the above disclosure is fully understood, many changes and modifications will become apparent to those skilled in the art. The appended claims are intended to be interpreted as covering all such changes and modifications.

[0055] The word "example" is used herein to mean used as an example, instance or illustration. Any aspect or design described as an "example" herein is not necessarily interpreted as being preferred or advantageous over other aspects or designs. On the contrary, the use of the word "example" is intended to present the concept in a concrete way. As used in this application, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X includes A or B" is intended to represent any one of the natural inclusive arrangements. That is, if X includes A; X includes B; or X includes both A and B, "X includes A or B" is satisfied under any of the aforementioned examples. In addition, the article "one" as used in this application and the appended claims should generally be interpreted as meaning "one or more", unless otherwise specified or clear from the context to refer to the singular form. In addition, the use of the term "one embodiment" or "one embodiment" throughout the text is not intended to represent the same embodiment or embodiment, unless described as such.

[0056] The embodiments of the systems, algorithms, methods, instructions, etc. described herein may be implemented in hardware, software, or any combination thereof. The hardware may include, for example, a computer, an intellectual property (IP) core, an application specific integrated circuit (ASIC), a programmable logic array, an optical processor, a programmable logic controller, microcode, a microcontroller, a server, a microprocessor, a digital signal processor, or any other suitable circuit. In the claims, the term "processor" should be understood to cover any of the foregoing hardware, either individually or in combination. The terms "signal" and "data" are used interchangeably.

[0057] As used herein, the term module may include a packaged functional hardware unit designed to be used with other components, a set of instructions executable by a controller (e.g., a processor executing software or firmware), processing circuits configured to perform specific functions, and independent hardware or software components that interface with a larger system. For example, a module may include an application specific integrated circuit (ASIC); a field programmable gate array (FPGA); an electrical circuit; a digital logic circuit; an analog circuit; a combination of discrete circuits, gates, and other types of hardware; or a combination thereof. In other embodiments, a module may include a memory that stores instructions that can be executed by a controller to implement the features of the module.

[0058] Furthermore, in one aspect, for example, a general purpose computer or general purpose processor with a computer program can be used to implement the systems described herein, which when executed implements any of the corresponding methods, algorithms and / or instructions described herein. Additionally or alternatively, for example, a special purpose computer / processor can be utilized, which may include other hardware for implementing any of the methods, algorithms or instructions described herein.

[0059] In addition, all or part of the embodiments of the present disclosure may take the form of a computer program product accessible from, for example, a computer usable medium or a computer readable medium. A computer usable medium or a computer readable medium may be any device that can, for example, tangibly contain, store, transmit, or transfer a program for use by or in conjunction with any processor. The medium may be, for example, an electronic device, a magnetic device, an optical device, an electromagnetic device, or a semiconductor device. Other suitable media are also available.

[0060] The above embodiments, implementations and aspects have been described to allow easy understanding of the present invention and do not limit the present invention. On the contrary, the present invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, and its scope should be given the broadest interpretation to cover all such modifications and equivalent structures permitted under the law.

Claims

1. A method for performing hysteresis adjustment in a steer-by-wire steering system of a vehicle, the method comprising: determining an expected hysteresis associated with rotating a steering wheel of the vehicle; Based on the expected hysteresis, determining whether to (i) perform a hysteresis reduction or (ii) perform a hysteresis increase; In response to determining that hysteresis reduction is to be performed, (i) calculating a hysteresis reduction value, (ii) modifying an estimated rack load based on the hysteresis reduction value, and (iii) generating a reference torque based on the estimated rack load modified according to the hysteresis reduction value; In response to determining that hysteresis increase is performed, (i) calculating a hysteresis increase value, and (ii) generating the reference torque based on the hysteresis increase value; as well as The steering wheel is controlled based on the reference torque.

2. The method according to claim 1, further comprising: The estimated rack load modified based on the hysteresis reduction value is provided to a force application function, and the force application function is used to generate a force application value.

3. The method according to claim 2, further comprising: The reference torque is generated based on the applied force value.

4. The method according to claim 1, further comprising: The estimated rack load is provided to a force function, and a force value is generated using the force function.

5. The method according to claim 4, further comprising: The reference torque is generated based on the applied force value.

6. The method according to claim 1, further comprising: The expected hysteresis is determined based on at least one of: (i) a direction of movement of the steering wheel and (ii) a determination of whether a driver input to the steering wheel is increasing or decreasing.

7. The method according to claim 1, further comprising: The estimated rack load is determined based on the estimated rack force.

8. A system for performing hysteresis adjustment in a steer-by-wire steering system of a vehicle, the system comprising: a sensor configured to sense a plurality of values ​​corresponding to operation of the steer-by-wire steering system; and A steering system controller is configured to perform the following operations based on the sensed multiple values: determining an expected hysteresis associated with rotating a steering wheel of the vehicle; Based on the expected hysteresis, determining whether to (i) perform a hysteresis reduction or (ii) perform a hysteresis increase; In response to determining that hysteresis reduction is to be performed, (i) calculating a hysteresis reduction value, (ii) modifying an estimated rack load based on the hysteresis reduction value, and (iii) generating a reference torque based on the estimated rack load modified according to the hysteresis reduction value; In response to determining that hysteresis increase is performed, (i) calculating a hysteresis increase value, and (ii) generating the reference torque based on the hysteresis increase value; as well as The steering wheel is controlled based on the reference torque. 9 . The system of claim 8 , wherein the steering system controller is further configured to provide the estimated rack load modified based on the hysteresis reduction value to a force apply function and to generate a force apply value using the force apply function. 10 . The system of claim 9 , wherein the steering system controller is further configured to generate the reference torque based on the applied force value.

11. The system of claim 8, wherein the steering system controller is further configured to provide the estimated rack load to a force application function and to generate a force application value using the force application function. 12 . The system of claim 11 , wherein the steering system controller is further configured to generate the reference torque based on the applied force value.

13. The system of claim 8, wherein the steering system controller is further configured to determine the expected hysteresis based on at least one of: (i) a direction of movement of the steering wheel and (ii) a determination of whether the driver's input to the steering wheel is increasing or decreasing.

14. The system of claim 8, wherein the steering system controller is further configured to determine the estimated rack load based on an estimated rack force.

15. A processor configured to execute instructions stored in a memory, wherein executing the instructions causes the processor to perform hysteresis adjustment in a steer-by-wire steering system of a vehicle, the instructions comprising: determining an expected hysteresis associated with rotating a steering wheel of the vehicle; Based on the expected hysteresis, determining whether to (i) perform a hysteresis reduction or (ii) perform a hysteresis increase; In response to determining that hysteresis reduction is to be performed, (i) calculating a hysteresis reduction value, (ii) modifying an estimated rack load based on the hysteresis reduction value, and (iii) generating a reference torque based on the estimated rack load modified according to the hysteresis reduction value; In response to determining that hysteresis increase is performed, (i) calculating a hysteresis increase value, and (ii) generating the reference torque based on the hysteresis increase value; as well as The steering wheel is controlled based on the reference torque.

16. The processor of claim 15, the instructions further comprising: The estimated rack load modified based on the hysteresis reduction value is provided to a force application function, and the force application function is used to generate a force application value.

17. The processor of claim 16, the instructions further comprising: The reference torque is generated based on the applied force value.

18. The processor of claim 15, the instructions further comprising: The estimated rack load is provided to a force function, and a force value is generated using the force function.

19. The processor of claim 18, the instructions further comprising: The reference torque is generated based on the applied force value.

20. The processor of claim 15, the instructions further comprising: The expected hysteresis is determined based on at least one of: (i) a direction of movement of the steering wheel and (ii) a determination of whether a driver input to the steering wheel is increasing or decreasing.

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