Transient steering system for steer-by-wire steering systems of vehicles

Abstract

A computer-implemented method, when executed by data processing hardware, causes the data processing hardware to perform operations including calibrating a transient steering algorithm using a reference steering ratio, and receiving a first set of vehicle data at the transient steering algorithm. The vehicle data includes one or more of vehicle speed, steering angle, lateral acceleration, yaw rate, and steering wheel torque. The operations include manipulating the reference steering ratio based on a steering angle gradient, determining a phasing gain based on a proportional transient variable and lateral and longitudinal accelerations via the transient steering algorithm, generating a first steering ratio, different from the reference steering ratio, in response to the first set of vehicle data via the transient steering algorithm, and adjusting steering control at the vehicle's steering system based on the first steering ratio.

Description

[0001] Foreword

[0002] The information provided in this section is for the purpose of presenting the general context of this disclosure. The work of the currently named inventors, to the extent described in this section and in respect of aspects of the description that may not otherwise be considered prior art at the time of filing, is neither expressly nor implicitly acknowledged as prior art to this disclosure. Technical Field

[0003] This disclosure generally relates to transient steering systems, and more specifically, to transient steering systems for steer-by-wire systems of vehicles. Background Technology

[0004] Vehicles are equipped with a steering mechanism, which includes a steering wheel mechanically connected to the vehicle's wheels. Many steering mechanisms include a steering shaft, steering column, or other mechanical structures to couple or otherwise provide steering movement between the steering wheel and the wheels.

[0005] Some vehicles can be equipped with a steer-by-wire system, which provides steering between the steering wheel and wheels without using a steering column. Steer-by-wire eliminates the mechanical connection and utilizes the relationship between the steering wheel and wheels, allowing the wheels to respond to the degree of steering wheel movement. However, many steer-by-wire implementations may not account for changes in vehicle acceleration or lateral movement, which can affect steering wheel movement in relation to the degree of steering wheel movement. Therefore, an improved steer-by-wire system is needed. Summary of the Invention

[0006] In some aspects, the computer-implemented method causes the data processing hardware to perform operations when executed by the data processing hardware. These operations include calibrating a transient steering algorithm using a reference steering ratio, and receiving a first set of vehicle data at the transient steering algorithm. The vehicle data includes one or more of vehicle speed, steering angle, lateral acceleration, yaw rate, and steering wheel torque. The operations also include manipulating the reference steering ratio based on a steering angle gradient, determining a phasing gain via the transient steering algorithm based on proportional transient variables and lateral and longitudinal accelerations, and generating a first steering ratio via the transient steering algorithm in response to the first set of vehicle data. The first steering ratio differs from the reference steering ratio. The operations also include adjusting steering control at the vehicle's steering system based on the first steering ratio.

[0007] The operation may optionally include receiving a second set of vehicle data at the transient steering algorithm and generating a second steering ratio in response to the second set of vehicle data. The second steering ratio may differ from the first steering ratio. The operation may also include adjusting steering control based on the second steering ratio. In some cases, generating the first and second steering ratios may include defining an updated ratio between the first steering ratio, the second steering ratio, and the wheel angle. Optionally, generating the first and second steering ratios may include using lateral acceleration to define the steering angle.

[0008] In some examples, the first steering ratio may correspond to a first rate of vehicle speed, and the second steering ratio may correspond to a second rate of vehicle speed, which is different from the first rate. Operation may include identifying a predetermined rate of change between the second set of vehicle data and the first set of vehicle data via a transient steering algorithm. Optionally, generating the second steering ratio may include comparing the second rate of vehicle speed with the predetermined rate of change. In some cases, the reference steering ratio and the first steering ratio may be defined by the quotient between the steering angle and the wheel angle.

[0009] In other aspects, the transient steering system for a vehicle's steer-by-wire system includes data processing hardware and memory hardware communicating with the data processing hardware. The memory hardware stores instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations. These operations include calibrating a transient steering algorithm using a reference steering ratio, and receiving a first set of vehicle data at the transient steering algorithm. The vehicle data includes one or more of vehicle speed, steering angle, lateral acceleration, yaw rate, and steering wheel torque. The operation also includes manipulating the reference steering ratio based on a steering wheel angle gradient, determining a phasing gain via the transient steering algorithm based on proportional transient variables and lateral and longitudinal accelerations, and generating a first steering ratio via the transient steering algorithm in response to the first set of vehicle data. The first steering ratio differs from the reference steering ratio. The operation also includes adjusting steering control at the vehicle's steer-by-wire system based on the first steering ratio.

[0010] The operation may optionally include receiving a second set of vehicle data at a transient steering algorithm and generating a second steering ratio, different from the first steering ratio, in response to the second set of vehicle data. In some cases, the operation may include adjusting steering control based on the second steering ratio. In some examples, generating the first and second steering ratios may include defining an updated ratio between the first steering ratio, the second steering ratio, and the wheel angle. Optionally, generating the first and second steering ratios may include using lateral acceleration to define the steering angle.

[0011] In some cases, the first steering ratio may correspond to a first rate of vehicle speed, and the second steering ratio may correspond to a second rate of vehicle speed, which is different from the first rate. The operation may also include identifying a predetermined rate of change between the second set of vehicle data and the first set of vehicle data via a transient steering algorithm. Optionally, generating the second steering ratio may include comparing the second rate of vehicle speed with the predetermined rate of change. In some examples, the reference steering ratio and the first steering ratio may be defined by the quotient between the steering angle and the wheel angle.

[0012] In other aspects, the transient steering system for a vehicle's steer-by-wire system includes data processing hardware and memory hardware communicating with the data processing hardware. The memory hardware stores instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations. These operations include calibrating a transient steering algorithm using a reference steering ratio, and receiving a first set of vehicle data at the transient steering algorithm. The vehicle data includes one or more of vehicle speed, steering angle, lateral acceleration, yaw rate, and steering wheel torque. The operation also includes manipulating the reference steering ratio based on a steering wheel angle gradient, determining a phasing gain via the transient steering algorithm based on proportional transient variables and lateral and longitudinal accelerations, and generating a first steering ratio via the transient steering algorithm in response to the first set of vehicle data. The first steering ratio differs from the reference steering ratio. The operation further includes adjusting steering control at the vehicle's steer-by-wire system based on the first steering ratio, receiving a second set of vehicle data at the transient steering algorithm, generating a second steering ratio in response to the second set of vehicle data, the second steering ratio differing from the first steering ratio, and adjusting steering control based on the second steering ratio.

[0013] In some examples, the base steering ratio and the first steering ratio can be defined by the quotient between the steering angle and the wheel angle. Attached Figure Description

[0014] The accompanying drawings described herein are for illustrative purposes only for the selected configurations and are not intended to limit the scope of this disclosure.

[0015] Figure 1 This is a schematic diagram of a vehicle equipped with a steer-by-wire system that includes a transient steering system according to the present disclosure;

[0016] Figure 2 It is a partial perspective view of the interior of a vehicle equipped with a transient steering system according to this disclosure;

[0017] Figure 3 This is an exemplary block diagram of a transient steering system according to the present disclosure;

[0018] Figure 4 This is a schematic diagram illustrating the operation of the transient steering system according to this disclosure;

[0019] Figure 5This is an exemplary graphical representation of a lookup table for a transient steering system according to the present disclosure;

[0020] Figure 6 and Figure 7 This is another schematic diagram illustrating the operation of the transient steering system according to this disclosure;

[0021] Figure 8-13 This is an exemplary graphical representation of the steering ratio, vehicle speed, acceleration, and steering wheel angle of a vehicle equipped with the transient steering system according to this disclosure compared to a reference vehicle without a transient steering system; and

[0022] Figure 14 This is an exemplary method of performing a transient steering system according to the present disclosure.

[0023] Throughout the accompanying drawings, corresponding reference numerals indicate the corresponding parts. Detailed Implementation

[0024] The example configuration will now be described more fully with reference to the accompanying drawings. The example configuration is provided so that this disclosure will be thorough and will fully communicate the scope of this disclosure to those skilled in the art. Specific details, such as examples of specific components, apparatus, and methods, are set forth to provide a thorough understanding of the configuration of this disclosure. It will be apparent to those skilled in the art that the specific details are not required, the example configuration can be implemented in many different forms, and the specific details and example configuration should not be construed as limiting the scope of this disclosure.

[0025] The terminology used herein is for the purpose of describing a particular exemplary configuration only and is not intended to be restrictive. As used herein, the singular articles “a,” “an,” and “the” may be intended to include plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having” are inclusive and therefore specify the presence of features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. Unless specifically identified as an order of execution, the method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown. Additional or alternative steps may be employed.

[0026] When an element or layer is referred to as being “on,” “joined to,” “connected to,” “attached to,” or “linked to” another element or layer, it may be directly on, joined to, connected to, attached to, or linked to the other element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as being “directly on,” “directly joined to,” “directly connected to,” “directly attached to,” or “directly linked to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0027] The terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers, and / or parts. These elements, components, regions, layers, and / or parts should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or part from another. Unless the context clearly indicates otherwise, terms such as “first,” “second,” and other numerical terms do not imply order or sequence. Therefore, without departing from the teachings of the example configuration, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part.

[0028] In this application, including the following definitions, the term "module" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include: application-specific integrated circuits (ASICs); digital, analog, or mixed-signal analog / digital discrete circuits; digital, analog, or mixed-signal analog / digital integrated circuits; combinational logic circuits; field-programmable gate arrays (FPGAs); processors (shared, dedicated, or grouped) that execute code; memories (shared, dedicated, or grouped) that store code executed by the processor; other suitable hardware components that provide the described functionality; or combinations of some or all of the foregoing, such as in a system-on-a-chip.

[0029] The term "code" as used above can include software, firmware, and / or microcode, and can refer to programs, routines, functions, classes, and / or objects. The term "shared processor" covers a single processor that executes some or all of the code from multiple modules. The term "group processor" covers a processor that, in combination with additional processors, executes some or all of the code from one or more modules. The term "shared memory" covers a single memory that stores some or all of the code from multiple modules. The term "group memory" covers memory that, in combination with additional memory, stores some or all of the code from one or more modules. The term "memory" can be a subset of the term "computer-readable medium." The term "computer-readable medium" does not include transient electrical and electromagnetic signals propagating through the medium, and therefore can be considered tangible and non-transitory memory. Non-limiting examples of non-transitory memory include tangible computer-readable media, which include non-volatile memory, magnetic memory, and optical memory.

[0030] The apparatus and methods described in this application can be implemented, in part or in whole, by one or more computer programs executed by one or more processors. The computer program includes processor-executable instructions stored on at least one non-transitory tangible computer-readable medium. The computer program may also include and / or depend on stored data.

[0031] A software application (i.e., a software resource) can refer to computer software that enables a computing device to perform tasks. In some examples, a software application may be referred to as an "application," "app," or "program." Example applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and game applications.

[0032] Non-transitory memory can be a physical device used to temporarily or permanently store programs (e.g., instruction sequences) or data (e.g., program state information) for use by a computing device. Non-transitory memory can be volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electrically erasable programmable read-only memory (EEPROM) (e.g., commonly used for firmware, such as boot programs). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase-change memory (PCM), and magnetic disks or magnetic tapes.

[0033] These computer programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and can be implemented using high-level procedural and / or object-oriented programming languages ​​and / or assembly / machine languages. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to any computer program product, non-transitory computer-readable medium, apparatus, and / or device (e.g., disk, optical disk, memory, programmable logic device (PLD)) used to provide machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term “machine-readable signal” refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0034] Various implementations of the systems and techniques described herein can be implemented in digital electronic and / or optical circuits, integrated circuits, specially designed ASICs (Application-Specific Integrated Circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementations in one or more computer programs executable and / or interpretable on a programmable system, which includes at least one programmable processor, which may be dedicated or general-purpose, coupled to receive data and instructions from a storage system, at least one input device, and at least one output device, and to transmit data and instructions to the storage system, at least one input device, and at least one output device.

[0035] The processes and logic described in this specification can be executed by one or more programmable processors (also known as data processing hardware) that execute one or more computer programs to perform functions by manipulating input data and generating output. The processes and logic can also be executed by special-purpose logic circuitry, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits). Processors suitable for executing computer programs include, for example, both general-purpose microprocessors and special-purpose microprocessors, as well as any one or more processors of any kind of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data, or operatively coupled to receive data from or transfer data to one or more mass storage devices, or both. However, a computer does not need to have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. Processors and memory may be supplemented by or incorporated into dedicated logic circuitry.

[0036] To provide interaction with a user, one or more aspects of this disclosure can be implemented on a computer having a display device for displaying information to the user, such as a CRT (cathode ray tube), LCD (liquid crystal display) monitor, or touchscreen, and optionally a keyboard and pointing device, such as a mouse or trackball, through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, voice, or tactile input. Furthermore, the computer can interact with the user by sending documents to and receiving documents from the device used by the user; for example, by sending a web page to a web browser on the user's client device in response to a request received from a web browser.

[0037] Reference Figure 1-3The vehicle 100 is equipped with a steer-by-wire system 102, which is configured with a transient steering system 10. The steer-by-wire system 102 includes a steering wheel 104 and wheels 106 of the vehicle 100. The steering wheel 104 is communicatively and operatively coupled to each of the wheels 106 via the steer-by-wire system 102 to perform steering maneuvers 108 of the vehicle 100. The steering wheel 104 may be configured as a conventional full-circle or round steering wheel 104, or it may be configured as an egg-shaped steering wheel 104. The steer-by-wire system 102 is configured to capture steering data 110 associated with the steering wheel 104 and wheel data 112 associated with the wheels 106. The steer-by-wire system 102 is also configured to communicate the steering data 110 and wheel data 112 with the transient steering system 10. The steering data 110 and wheel data 112 may be included as part of vehicle data 114 provided from the steer-by-wire system 102 to the transient steering system 10. Vehicle data 114 may also include, but is not limited to, lateral acceleration 116, yaw rate 118, and vehicle speed 120. Steering data 110 may include, but is not limited to, steering angle 110a and steering wheel torque 110b.

[0038] The transient steering system 10 includes an electronic control unit (ECU) 12 configured with a transient steering algorithm 14. The transient steering algorithm 14 receives steering data 110 and wheel data 112. The ECU 12 includes data processing hardware 16 configured to execute the transient steering algorithm 14 and memory hardware 18 communicating with the data processing hardware 16. The memory hardware 18 stores instructions that, when executed on the data processing hardware 16, cause the data processing hardware 16 to perform the operations described herein. The transient steering algorithm 14 is configured with a steering ratio 20 associated with the steer-by-wire system 102. For example, the transient steering algorithm 14 may initially be calibrated with a reference steering ratio 20a. The reference steering ratio 20a may also be established after a predetermined duration of operation of the vehicle 100.

[0039] Steering ratio 20 reflects the effect of steering angle 110a on wheel angle 112a. For example, the larger the steering ratio 20, the smaller the effect of steering angle 110a on wheel angle 112a. In other words, the operator will maneuver steering wheel 104 to a larger steering angle 110a to result in a desired change in wheel angle 112a at a high steering ratio 20. In contrast, a lower or smaller steering ratio 20 can give the operator the ability to make small changes to steering angle 110a to achieve a larger change in wheel angle 112a. Therefore, when steering ratio 20 is low, wheel 106 can have increased responsiveness to steering wheel 104, while when steering ratio 20 is high, wheel 106 can have decreased responsiveness to steering wheel 104. In addition to steering angle 110a and wheel angle 112a, steering ratio 20 is also affected by other vehicle data 114, including but not limited to lateral acceleration 116, yaw rate 118, and vehicle speed 120 at the initial measurement.

[0040] As described above, the steering ratio 20 includes a reference steering ratio 20a, which represents an initial steering ratio 20a that can be configured as part of the steer-by-wire system 102. For example, the reference steering ratio 20a can be predetermined based on average vehicle data 114 stored in a server, or it can be calculated after a predetermined duration of the initial operation time of the vehicle 100. The reference steering ratio 20a is designed as a starting point from which the transient steering system 10 can adjust the effect of the movement of the steering wheel 104 on the wheels 106. The transient steering system 10 communicates changes in the steering ratio 20 (i.e., adjustments to the reference steering ratio 20a) to the steer-by-wire system 102, and the steer-by-wire system 102 implements changes in the steering ratio 20 at the steering wheel 104 and the wheels 106.

[0041] The transient steering algorithm 14 is configured to apply a phasing gain 22 in response to vehicle data 114 based on the steering ratio 20. As an example, and not a limitation, the phasing gain 22 can be applied in response to vehicle data 114 reflecting either a braking event or a high lateral acceleration event (i.e., a high gravity (G) force event). The steer-by-wire system 102 utilizes the phasing gain 22 to gradually stop or delay the movement of the wheels 106 in response to detected movement of the steering wheel 104. Therefore, the phasing gain 22 is proportional to the steering ratio 20 to alter the responsiveness of the wheels 106 to the steering wheel 104.

[0042] Further reference Figure 1-3The transient steering algorithm 14 is configured to set and adjust the steering ratio 20 in response to vehicle data 114, as described above, after the reference steering ratio 20a has been calibrated. During operation of vehicle 100, the transient steering algorithm 14 receives a first set 114a of vehicle data 114 from the steer-by-wire system 102. The first set 114a of vehicle data 114 is captured during a predetermined time frame of operation of vehicle 100. For example, the first set 114a may reflect changes in one or more of lateral acceleration 116, yaw rate 118, and vehicle speed 120. Based on the first set 114a of vehicle data 114, the transient steering algorithm 14 may adjust or otherwise change the steering ratio 20 to generate a first steering ratio 20b that is different from the reference steering ratio 20a. For example, the transient steering algorithm 14 may manipulate the reference steering ratio 20a based on the steering angle gradient 110c of steering data 110. The steering angle gradient 110c is calculated by the transient steering algorithm 14 based on the vehicle speed 120 and the steering angle 110a, and reflects the steering wheel speed 110d.

[0043] The transient steering algorithm 14 can then determine the phasing gain 22 based on the proportional transient variable 24 and the lateral acceleration 116 and longitudinal acceleration 122 of the vehicle data 114. The proportional transient variable 24 can be stored in a lookup table 26, which can be stored in memory hardware 18. Figure 5 An exemplary lookup table 26 is shown. Lookup table 26 may include a two-dimensional lookup table 26a and various one-dimensional lookup tables 26b-d. Lookup table 26 is adjustable relative to the steering angle gradient 110c and the vehicle speed 120. For example, lookup table 26 is shown as phasing gain 22 along the y-axis, steering wheel speed 110d along the x-axis, and vehicle speed 120 along the z-axis. Transient steering algorithm 14 may utilize lookup table 26 to at least partially determine an updated steering ratio 20b (i.e., a first steering ratio 20b) using phasing gain 22. Transient steering algorithm 14 communicates the first steering ratio 20b with steer-by-wire system 102, and steer-by-wire system 102 adjusts steering control 130 based on the first steering ratio 20b. As described above, the first steering ratio 20b differs from the reference steering ratio 20a. The first steering ratio 20b and the second steering ratio 20c are defined by a quotient 111 between the steering angle 110a and the wheel angle 112a.

[0044] During operation of vehicle 100, steer-by-wire system 102 continues to collect and monitor vehicle data 114 and continuously sends vehicle data 114 to transient steering system 10 for evaluation. For example, transient steering system 10 may receive a second set 114b of vehicle data 114 from steer-by-wire system 102 after adjusting steering ratio 20 in response to a first set 114a of vehicle data 114. The second set 114b of vehicle data 114 may differ from the first set 114a of vehicle data 114, allowing transient steering algorithm 114 to generate a second steering ratio 20c. Transient steering algorithm 14 defines an update ratio 28 between the first steering ratio 20b, the second steering ratio 20c, and wheel angle 112a. Steer-by-wire system 102 receives the second steering ratio 20c from transient steering system 10 and adjusts steering control 130 based on the second steering ratio 20c. In some cases, the transient steering algorithm 14 can be configured with a predetermined rate of change 30 associated with the second steering ratio 20c, which is described in more detail below.

[0045] In a non-limiting example, the transient steering algorithm 14 can utilize lateral acceleration 116 to define the steering angle 110a. Lateral acceleration 116 can be changed from a first set 114a of vehicle data 114 to a second set 114b of vehicle data 114, thereby instructing the transient steering algorithm 14 that the steering ratio 20 should be adjusted. For example, vehicle 100 may enter a turn or curve corresponding to a high G-force event. The transient steering algorithm 14 can compare the second set 114b of vehicle data 114 with the first set 114a to generate a second steering ratio 20c. In this non-limiting example, the second steering ratio 20c can be greater than the first steering ratio 20b to reduce the effect of steering angle 110a on wheel angle 112a.

[0046] In another non-limiting example, the transient steering algorithm 14 may utilize the vehicle speed 120 to define the steering ratio 20. For example, the transient steering algorithm 14 may initially receive a first set 114a of vehicle data 114 including a first speed 120a, and subsequently receive a second set 114b of vehicle data 114 including a second speed 120b different from the first speed 120a. The transient steering algorithm 14 is configured to evaluate the difference between the first speed 120a and the second speed 120b to determine how to adjust the steering ratio 20. For example, if there is a large drop in vehicle speed 120 from the first speed 120a to the second speed 120b, the steering ratio 20 may be increased to limit the effect of the steering angle 110a on the wheel angle 112a. In this non-limiting example, the increased steering ratio 20 results in a large movement or adjustment of the steering wheel 104, thereby achieving a small movement or adjustment at the wheel 106.

[0047] The predetermined rate of change 30 can be stored in memory hardware 18 and can be defined relative to vehicle speed 120. For example, the predetermined rate of change 30 is a defined change threshold for vehicle speed 120 at which transient steering algorithm 14 is triggered to increase or decrease steering ratio 20 (i.e., change steering ratio 20 from a first steering ratio 20b to a second steering ratio 20c). Therefore, when transient steering algorithm 14 receives the second set 114b of vehicle data 114, transient steering algorithm 14 compares the second rate 120b with the predetermined rate of change 30 to determine whether to adjust or change steering ratio 20.

[0048] Now for reference Figure 3-7 An exemplary diagram is shown for performing transient steering algorithm 14. Figure 4 A first flowchart 400 is shown, utilizing the steering angle 110a at 402 and the vehicle speed 120 at 404. The transient steering algorithm 14 calculates the steering angle gradient 110c at 406. Based on the steering angle gradient 110c and the vehicle speed 120, the transient steering algorithm 14 evaluates lookup table 26 (in...) at 408. Figure 5 (shown in the figure) to determine the phasing gain 22. The phasing gain 22 is a function of the vehicle speed 120 and the steering wheel speed 110d. The transient steering algorithm 14 then applies the transfer function 32 at 410 to the phasing gain 22 to increase or decrease the steering ratio 20. A value of -1 is added at 412, so the result is a scalar on the steering ratio 20, which produces the steering wheel speed portion 110d1 at 414.

[0049] Figure 6 Another flowchart 600 is shown, utilizing the lateral acceleration 116 at 602 and the vehicle speed 120 at 604. At 606, the absolute value of the lateral acceleration 116 is determined, and at 608, it is placed into a one-dimensional lookup table 26b. At 610, the vehicle speed 120 is converted from kilometers per hour to meters per second. The transient steering algorithm 14 then calculates the longitudinal acceleration 122 at 612, and applies a scalar at 614 via a second one-dimensional lookup table 26c. The second one-dimensional lookup table 26c contains both positive and negative values, while the one-dimensional lookup table 26b contains only positive values. Positive values ​​represent acceleration, and negative values ​​represent braking. At 616, the scaled values ​​generated by the one-dimensional lookup tables 26b and 26c are multiplied, and at 618, a transfer function 332 is applied to smooth the signal. At 620, another one-dimensional table 26d is applied to the phase gain 22, thereby producing one of the damping gain 34 at 622 and the damping of the phase gain 22 at 624.

[0050] Figure 7Another flowchart 700 is shown, which utilizes the vehicle speed 120 at 702 and operates in a loop utilizing the damping gain 34 from flowchart 600. At 704, the transient steering algorithm 14 executes the transfer function 32 by adding or subtracting the vehicle speed 120 from other signals. At 706, the integrator 36 of the transient steering algorithm 14 outputs a signal 38. In one instance, signal 38 is multiplied by the damping gain 34 at 708 and then loops back to the transfer function 32 at 704. In another instance, signal 38 is adjusted by removing the phasing gain 22 at 710 and then loops back to the transfer function 32 at 704. Signal 38 can also be input into a two-dimensional lookup table 26a along with the steering angle 110a at 712, which produces a steering ratio 20 with the phasing gain 22 at 714.

[0051] Transient steering algorithm 14 uses each of flowcharts 400, 600, and 700 to calculate steering ratio 20 using various vehicle data 114. Once transient steering algorithm 14 determines steering ratio 20 with phase gain 22 at 714, it multiplies steering ratio 20 with phase gain 22 by the steering wheel speed portion 110d1 generated at 412. This calculation produces a final steering ratio 20 used by steering-by-wire system 102. As described herein, transient steering algorithm 14 is configured to perform these steps in response to detected changes in steering angle 110a and / or other vehicle data 114 that may indicate that a decrease or increase in steering ratio 20 would benefit the performance of vehicle 100. Transient steering algorithm 14 is configured to perform these calculations during transient periods between phases of maneuvering, such that changes in steering ratio 20 are gradual to the operator.

[0052] Figure 8-13 A graphical example illustrating the effect of implementing transient steering algorithm 14 is shown. For example, Figure 7 The steering ratio 20 at a given time is shown. In this example, if the steering ratio 20 reads eighteen (18) degrees at the steering wheel 104, the road wheel 106 will read one (1) degree. As a result, the steering ratio 20 is eighteen (18). In the same example, if the vehicle 100 is operating at a speed 120 of approximately 100 kilometers per hour (kph) and brakes are applied to shift to twenty (20) kph, the steering ratio 20 will decrease, resulting in greater control of the vehicle 100. For example, when decreasing from 100 kph to twenty (20) kph, the steering ratio 20 can decrease from approximately eighteen (18) to approximately eight (8).

[0053] Figure 8The baseline data shows that without steering ratio 20, phasing gain 22 will be proportional to the acceleration level and lateral acceleration level. As a result, if there is rapid braking, the steering angle 110a relative to wheel angle 112a can remain constant. In contrast, transient steering algorithm 14 follows the change in braking, allowing steering ratio 20 to change slowly in response to slow braking maneuvers and rapidly in response to rapid braking maneuvers. Transient steering algorithm 14 is therefore configured to make the transition from vehicle 100 operating at high speed smoother compared to the transition to operating at a slower speed. For example, when vehicle 100 is operating at high speed, steering ratio 20 is higher relative to when vehicle 100 is operating at a slower speed. A higher steering ratio 20 results in minimal impact on wheel 106, allowing the operator to make small adjustments to steering wheel 104 with minimal to no impact on wheel 106.

[0054] In contrast, when operating at slower speeds, the steering ratio 20 is lower, therefore the steering wheel 104 has a greater impact on the wheels 106. The transient steering algorithm 14 is also configured to smooth the transition of the steering ratio 20 between high and low vehicle speeds 120, resulting in improved driving performance and handling of the vehicle 100. As described above, the transient steering algorithm 14 is configured to monitor vehicle data 114 to determine the degree of adjustment to the steering ratio 20. The transient steering algorithm 14 is configured with multiple calibration settings 40, such as... Figure 9 As shown, the steering ratio 20 is adjusted. For example, a first calibration setting 40a may correspond to aggressive (i.e., rapid) braking maneuvers, while a second calibration setting 40b may correspond to slower braking maneuvers. The first calibration setting 40a may be represented by low gain, and the second calibration setting 40b may be represented by high gain.

[0055] Calibration setting 40 can correspond to lateral acceleration 116. For example, Figure 10 Examples are shown of a first calibration setting 40a corresponding to low lateral acceleration 116a and a second calibration setting 40b corresponding to high lateral acceleration 116b. The steering ratio 20 can be adjusted based on the calibration setting 40 in response to the detected lateral acceleration 116. Therefore, the more aggressive (i.e., stronger) the gravitational (G) force generated by the lateral acceleration 116, the slower the change in steering ratio 20. This provides the operator with a sense of improved control of the vehicle 100 during operation through high G-force zones on roads that result in high levels of lateral acceleration 116. For example, the transient steering algorithm 14 is configured to have a smaller change in steering ratio 20 at corners with high lateral acceleration 116b compared to corners with low lateral acceleration 116a.

[0056] The transient steering algorithm 14 is also configured to respond to the steering angle 110a based on the rate of change of the steering angle 110a (i.e., how quickly the operator changes the steering angle 110a). For example, Figure 12 The diagram illustrates the change of steering angle 110a from zero (0) degrees to forty (40) degrees at a high speed 120 (i.e., fast), and relatively from zero (0) degrees to forty (40) degrees at a low speed 120 (i.e., slow). The transient steering algorithm 14 is configured to change the steering ratio 20 during the transition from zero (0) to forty (40). Therefore, steering angle 110a and wheel angle 112a will change due to the change in steering ratio 20, such that during the transient time of the change in steering ratio 20, steering angle 110a will have a greater or lesser effect on wheel angle 112a, depending at least in part on vehicle speed 120. The result of changing steering ratio 20 via transient steering algorithm 14 is a faster or slower response of wheel 106 to manipulations made at steering wheel 104 during the transient time between vehicle speeds 120.

[0057] In some cases, vehicle 100 can be configured to tow another object, such as a trailer. In this example, as... Figure 13 As shown, due to the transient steering algorithm 14, aggressive (i.e., rapid or fast) steering at the steering wheel 104, and therefore aggressive changes in the steering angle 110a, will not result in rapid changes in the wheel angle 112a. The transient steering algorithm 14 will correct for this steering and will adjust the steering ratio 20 accordingly. The transient steering algorithm 14 is configured to adjust the steering ratio 20 in real time, such that the steering ratio 20 can increase in response to aggressive steering and decrease once the aggressive steering has stopped. The transient steering algorithm 14 is configured to provide smooth or otherwise slight changes to the steering ratio 20 over a period of time to minimize the impact on the operator.

[0058] refer to Figure 14An exemplary method 1400 of a transient steering system 10 is illustrated. At 1402, the transient steering system 10 calibrates a transient steering algorithm 14 with a reference steering ratio 20a. The transient steering algorithm 14 receives a first set 114a of vehicle data 114 at 1404. The vehicle data 114 includes one or more of vehicle speed 120, steering angle 110a, lateral acceleration 116, yaw rate 118, and steering wheel torque 110b. At 1406, the transient steering algorithm 14 manipulates the reference steering ratio 20a based on a steering angle gradient 110c. At 1408, the transient steering algorithm 14 determines a phasing gain 22 based on a proportional transient variable 24, as well as lateral acceleration 116 and longitudinal acceleration 122. At 1410, the transient steering algorithm 14 generates a first steering ratio 20b in response to the first set 114a of the vehicle data 114. The first steering ratio 20b differs from the reference steering ratio 20a. At 1412, the steer-by-wire system 102 of vehicle 100 adjusts steering control 130 based on a first steering ratio 20b. Transient steering algorithm 14 receives a second set 114b of vehicle data 114 at 1414 and generates a second steering ratio 20c at 1416 in response to the second set 114b of vehicle data 114. The second steering ratio 20c differs from the first steering ratio 20b. At 1418, the steer-by-wire system 102 adjusts steering control 130 based on the second steering ratio 20c.

[0059] Many embodiments have been described. However, it should be understood that various modifications can be made without departing from the spirit and scope of this disclosure. Therefore, other embodiments are within the scope of the appended claims.

[0060] The foregoing description has been provided for purposes of illustration and description. It is not intended to be exhaustive or limiting of this disclosure. Elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable where applicable and can be used in selected configurations, even if not specifically shown or described. They can also be varied in many ways. Such variations should not be considered as departing from this disclosure, and all such modifications are intended to be included within the scope of this disclosure.

Claims

1. A computer-implemented method, when executed by data processing hardware, causes the data processing hardware to perform an operation, the operation comprising: The transient steering algorithm is calibrated using a reference steering ratio; The transient steering algorithm receives a first set of vehicle data, which includes one or more of vehicle speed, steering angle, lateral acceleration, yaw rate, and steering wheel torque. The reference steering ratio is manipulated based on the steering angle gradient; The phase gain is determined by a transient steering algorithm based on proportional transient variables and lateral and longitudinal accelerations. In response to the first set of vehicle data, a first steering ratio is generated via the transient steering algorithm, the first steering ratio being different from the reference steering ratio; and At the vehicle's steering system, steering control is adjusted based on a first steering ratio.

2. The method of claim 1, further comprising receiving a second set of vehicle data at the transient steering algorithm and generating a second steering ratio in response to the second set of vehicle data, the second steering ratio being different from the first steering ratio.

3. The method according to claim 2, further comprising adjusting the steering control based on a second steering ratio.

4. The method of claim 3, wherein generating the first steering ratio and the second steering ratio includes defining an updated ratio between the first steering ratio, the second steering ratio, and the wheel angle.

5. The method of claim 3, wherein generating the first steering ratio and the second steering ratio includes using the lateral acceleration to define the steering angle.

6. The method of claim 2, wherein the first steering ratio corresponds to a first rate of the vehicle speed, and the second steering ratio corresponds to a second rate of the vehicle speed, the second rate being different from the first rate.

7. The method of claim 6, further comprising identifying a predetermined rate of change between the second set of vehicle data and the first set of vehicle data via the transient steering algorithm.

8. The method of claim 7, wherein generating the second steering ratio comprises comparing a second rate of the vehicle speed with the predetermined rate of change.

9. The method of claim 1, wherein the reference steering ratio and the first steering ratio are defined by the quotient between the steering angle and the wheel angle.

10. A transient steering system for a steer-by-wire system of a vehicle, the transient steering system being configured to perform the method according to claim 1.

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