SYSTEM AND METHOD FOR TRACK CENTERING CONTROL WITH ACTIVE REAR WHEEL STEERING

Abstract

A computer-implemented procedure which, when performed by data processing hardware, causes the data processing hardware to perform operations that include determining a desired effective steering angle based on a desired path, measuring an angle of the front road wheels and an angle of the rear road wheels, determining an actual effective steering angle, determining an error of the effective steering angle based on the desired effective steering angle and the actual effective steering angle, generating a torque command for an electronic power steering system based on the error of the effective steering angle, and controlling an active rear-wheel steering system independently of the electronic power steering system.

Description

INTRODUCTION

[0001] The present invention relates to a computer-implemented method. The present disclosure relates generally to a method for controlling the steering of a vehicle and, in particular, to controlling a vehicle with an advanced driver assistance system and an active rear-wheel steering system.

[0002] For example, German patent application DE 10 2015 212 229 A1 describes a computer-implemented method according to the preamble of claim 1. German patent applications DE 10 2013 200 132 A1 and DE 10 2012 212 301 A1 describe related methods.

[0003] Generally, vehicles are equipped with an Advanced Driver Assistance System (ADAS) to maintain vehicle control during both manual and automated driving. Some vehicles are also equipped with an Active Rear-Wheel Steering (ARS) system. Active rear-wheel steering can improve the vehicle's turning radius and maneuverability by turning the rear wheels in the opposite direction to the front wheels. Furthermore, active rear-wheel steering can ensure smooth lane changes and improve stability at high speeds by turning the rear wheels in the same direction as the front wheels. In existing systems, the ADAS cannot control the rear-wheel steering angle of the active rear-wheel steering system.This forces the rear wheel steering angle to zero to simplify vehicle control when the ADAS is controlling the vehicle during manual or automated driving.

[0004] It is an object of the present invention to address one or more shortcomings of existing systems and methods.

[0005] The aforementioned problem is solved by the features of claim 1. Advantageous embodiments of the invention are described in the dependent claims, the description, and the drawings.

[0006] According to the invention, a computer-implemented method is provided which, when performed by data processing hardware, causes the data processing hardware to perform operations. These operations include determining a desired effective steering angle based on a desired vehicle path, measuring the angle of the front and rear wheels, determining the actual effective steering angle, determining the effective steering angle error based on the desired and actual effective steering angles, generating a torque command for an electronic power steering system based on the effective steering angle error, and controlling an active rear-wheel steering system independently of the electronic power steering system.

[0007] The rear wheel angle is a low-resolution angle of the rear wheels. The method further includes measuring a handwheel angle and estimating a high-resolution rear wheel angle using the low-resolution rear wheel angle, the handwheel angle, and a predictive ratio.

[0008] According to at least one aspect, determining the actual effective steering angle may involve evaluating a difference between the angle of the front road wheels and the high-resolution angle of the rear road wheels.

[0009] According to at least one aspect, determining the actual effective steering angle may also involve evaluating a difference between the angle of the front road wheels and the angle of the rear road wheels.

[0010] According to another aspect, determining the error of the effective steering angle may also involve determining a difference between the desired effective steering angle and the actual effective steering angle.

[0011] According to at least one example, the active rear-wheel steering system can be configured to be optionally controlled while an advanced driver assistance system is enabled. Controlling the active rear-wheel steering system can further include disabling the active rear-wheel steering system if the advanced driver assistance system is enabled and either: (i) the angle of the rear road wheels is less than a first threshold, or (ii) the vehicle is traveling at a speed less than a second threshold.

[0012] According to another example, the method also includes adjusting the angle of the front road wheels of one or more front wheels of the vehicle based on the torque command.

[0013] According to another, not independently claimed configuration, a system is provided and contains data processing hardware and storage hardware in communication with the data processing hardware, the storage hardware storing instructions which, when executed in the data processing hardware, cause the data processing hardware to perform operations.The operations include determining a desired effective steering angle based on a desired vehicle path, measuring an angle of the front road wheels and an angle of the rear road wheels, determining an actual effective steering angle, determining an effective steering angle error based on the desired effective steering angle and the actual effective steering angle, generating a torque command for an electronic power steering system based on the effective steering angle error, and controlling an active rear-wheel steering system independently of the electronic power steering system.

[0014] The system may include one or more of the following optional aspects or steps. For example, determining the actual effective steering angle may further include evaluating the difference between the angle of the front road wheels and the angle of the rear road wheels.

[0015] According to at least one aspect, determining the error of the effective steering angle may also include determining a difference between the desired effective steering angle and the actual effective steering angle.

[0016] According to another aspect, controlling the active rear-wheel steering system may also include deactivating the active rear-wheel steering system if the advanced driver assistance system is enabled and either: (i) the angle of the rear road wheels is less than a first threshold or (ii) the vehicle is traveling at a speed less than a second threshold.

[0017] According to yet another, not independently claimed configuration, a vehicle management system is provided, comprising an advanced driver assistance system for maintaining vehicle control, an active rear-wheel steering system, and a compensation module for the active rear-wheel steering system, which includes a feature state module. Furthermore, the vehicle management system includes a computer system containing data processing hardware and storage hardware communicating with the data processing hardware, the storage hardware storing instructions which, when executed in the data processing hardware, cause the data processing hardware to perform operations.The operations include determining a desired effective steering angle based on a desired vehicle path, measuring an angle of the front road wheels and an angle of the rear road wheels, determining an actual effective steering angle, determining an error of the effective steering angle based on the desired effective steering angle and the actual effective steering angle, generating a torque command for an electronic power steering system based on the error of the effective steering angle, and controlling an active rear-wheel steering system independently of the electronic power steering system.

[0018] The vehicle management system may include one or more of the following optional aspects or steps. For example, determining the actual effective steering angle may further include evaluating the difference between the angle of the front road wheels and the angle of the rear road wheels. Determining the error of the effective steering angle may further include determining the difference between the desired effective steering angle and the actual effective steering angle.

[0019] According to at least one aspect, the feature state module can be configured to control the state of the active rear-wheel steering system. The active rear-wheel steering system can be deactivated if the advanced driver assistance system is enabled and either: (i) the angle of the rear road wheels is less than a first threshold, or (ii) the vehicle is traveling at a speed less than a second threshold. If the advanced driver assistance system is enabled and the angle of the rear road wheels is greater than a first threshold and the vehicle speed is greater than a second threshold, the state of the active rear-wheel steering system can remain unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described here serve only to illustrate selected configurations; they show: Fig. 1 a schematic representation of a vehicle environment containing a vehicle management system according to the principles of the present disclosure; Fig. 2 an enlarged schematic representation of an example of the vehicle management system according to the principles of the present disclosure; Fig. 3 a schematic representation of a resolution upsampling module according to the principles of the present disclosure; Fig. 4. A flowchart of operations of the vehicle management system Fig. 2; Fig. 5 a flowchart of operations of the resolution upsampling module Fig. 3; and Fig. 6. A schedule of operations of the vehicle management system. Fig. 2.

[0021] Corresponding reference symbols throughout the drawings denote corresponding parts. DETAILED DESCRIPTION

[0022] Exemplary configurations are now described in more detail with reference to the accompanying drawings. To provide a thorough understanding of the configurations of this disclosure, specific details such as examples of specific components, devices, and processes are presented. It is clear to the person skilled in the art that specific details need not be used and that exemplary configurations can be embodied in many different forms.

[0023] The terminology used here serves only to describe certain exemplary configurations and is not intended to be restrictive. Unless the context clearly indicates otherwise, the singular articles "a," "an," and "that," as used here, are intended to include the plural forms. The terms "includes," "comprehensive," "containing," and "exhibiting" are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more further features, steps, operations, elements, components, and / or groups thereof. Unless a specific order of execution is given, the procedural steps, processes, and operations described herein should not be understood as requiring their execution in the particular order discussed or presented.Additional or alternative steps can be used.

[0024] When an element or layer is described as "on," "interacting with," "connected with," "attached to," or "coupled with" another element or layer, it may be directly on, interacting with, connected with, attached to, or coupled with the other element or layer, or there may be intermediate elements or layers. Conversely, no intermediate elements or layers may be present when an element is described as "directly on," "directly interacting with," "directly connected with," "directly attached to," or "directly coupled with" another element or layer. Other words used to describe the relationship between elements (e.g., "between" versus "directly between," "adjacent to" versus "directly adjacent to," etc.) are to be interpreted in the same way.As the term “and / or” is used here, it includes any combination of one or more of the associated listed objects.

[0025] The terms "first," "second," "third," etc., may be used here to describe different elements, components, areas, layers, and / or sections. These elements, components, areas, layers, and / or sections are not intended to be limited by these terms. These terms may only be used to distinguish one element, component, area, layer, or section from another. Unless clearly indicated by the context, terms such as "first," "second," and other numerical terms do not imply a sequence or order.Thus, a first element, a first component, a first area, a first layer or a first section discussed below could be referred to as a second element, a second component, a second area, a second layer or a second section without deviating from the lessons of the exemplary configurations.

[0026] In this application, including in the following definitions, the term "module" may be replaced by the term "circuit". The term "module" may refer to, be a part of, or include an application-specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combination logic circuit; a free programmable logic array (FPGA); a processor (shared, dedicated, or group) that executes code; memory (shared, dedicated, or group) that stores code executed by a processor; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-a-chip.

[0027] 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" includes a single processor that executes some or all of the code from multiple modules. The term "group processor" includes a processor that executes some or all of the code from one or more modules along with additional processors. The term "shared memory" includes a single memory that stores some or all of the code from multiple modules. The term "group memory" includes memory that stores some or all of the code from one or more modules along with additional memory. The term "memory" can be a subset of the term "computer-readable medium."The term "computer-readable medium" excludes transitory electrical and electromagnetic signals propagating through a medium and can therefore be considered a concrete, non-transient storage medium. Non-restrictive examples of non-transient storage include a concrete, computer-readable medium, such as non-volatile storage, magnetic storage, and optical storage.

[0028] The devices and methods described in this application can be implemented in whole or in part by one or more computer programs executed by one or more processors. The computer programs contain instructions executable by a processor, stored on at least one non-transient, concrete, computer-readable medium. Furthermore, the computer programs can contain and / or rely on stored data.

[0029] A software application (i.e., a software resource) can refer to computer software that causes a computer device to perform a task. Depending on the context, a software application may be called an "application," an "app," or a "program." Examples of applications include, but are not limited to, system diagnostics applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and gaming applications.

[0030] Non-transient memory can be a physical device used to store programs (e.g., sequences of instructions) or data (e.g., program state information) on a temporary or permanent basis for use by a computer device. Non-transient 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) / electronically erasable programmable read-only memory (EEPROM) (which is commonly used, for example, for firmware such as boot programs).Examples of volatile memory include, but are not limited to, read / write memory (RAM), dynamic read / write memory (DRAM), static read / write memory (SRAM), phase change memory (PCM), disks or tapes.

[0031] These computer programs (also known as programs, software, software applications, or code) contain machine instructions for a programmable processor and can be implemented in a higher-level procedural and / or object-oriented programming language and / or in assembly language / machine language. As used here, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, any non-transient computer-readable medium, any device, and / or any apparatus (e.g., magnetic disks, optical disks, memory, programmable logic devices (PLDs)) used to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal.The term "machine-readable signal" refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0032] Various implementations of the systems and techniques described herein can be realized in a digital electronic and / or optical circuit arrangement, in an integrated circuit arrangement, in specially designed ASICs (application-specific integrated circuits), in computer hardware, in computer firmware, in computer software, and / or in combinations thereof. These various implementations may include implementations in one or more computer programs that are executable and / or interpretable in a programmable system that contains at least one programmable processor, which may be a special-purpose or general-purpose processor, coupled to a storage system, at least one input device, and at least one output device for receiving data and instructions from and sending data and instructions to a storage system.

[0033] The processes and logic sequences described in this description can be executed by one or more programmable processors, also known as data processing hardware, which run one or more computer programs to perform functions by processing input data and generating output. Alternatively, the processes and logic sequences can be executed by a specialized logic circuit arrangement, such as an FPGA (free programmable logic assembly) or an ASIC (application-specific integrated circuit). Processors suitable for executing a computer program include, for example, general-purpose and specialized microprocessors, as well as any type of digital computer processor(s). Generally, a processor receives instructions and data from read-only memory, read / write memory, or both.The essential elements of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Generally, a computer also includes one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, or is functionally coupled to them to receive data from them, send data to them, or both. However, a computer need not have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage 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.The processor and memory can be supplemented by or integrated into a special logic circuit arrangement.

[0034] To provide interaction with a user, one or more aspects of the disclosure can be implemented in a computer that has a display device, such as a CRT (cathode ray tube) monitor, an LCD (liquid crystal display) monitor, or a touchscreen, for displaying information to the user, and optionally a keyboard and pointing device, such as a mouse or trackball, by which the user can provide input to the computer. Other types of devices can also be used to provide interaction with a user; for example, feedback provided to the user can be any form of sensory feedback, such as...This feedback can be visual, audible, or tactile; and input can be received from the user in any form, including acoustic, speech, or keystroke input. Furthermore, a computer can interact with a user by sending documents to and receiving documents from a device used by the user; for example, by sending web pages to a web browser on a user's client device in response to requests received by the web browser.

[0035] In Fig. Figure 1 presents an exemplary vehicle operating environment 10 to illustrate the principles of this disclosure. The vehicle operating environment 10 contains a vehicle service center 20. For illustrative purposes, the vehicle operating environment 10 is shown as containing a single vehicle service center 20. However, according to other examples, the vehicle operating environment 10 can contain multiple vehicle service centers 20 communicating over a network 40 (e.g., the Internet, cellular networks).

[0036] The vehicle operating environment 10 includes a vehicle 100. The vehicle 100 contains a vehicle body 102 coupled to one or more front wheels 104 and one or more rear wheels 106. The vehicle 100 also includes a vehicle management system 110, which comprises a sensor system 120, a computer system 130, an advanced driver assistance system (ADAS) 140, a steering controller 150, an electronic power steering system (EPS system) 160, an active rear-wheel steering system (ARS system) 170, and an active rear-wheel steering compensation module 200. The vehicle management system 110 can be configured to collect information from the vehicle 100 and / or from a driver (i.e., an operator) to enhance ADAS control during manual and automated driving.

[0037] While the vehicle 100 maneuvers in the environment 10, the sensor system 120 comprises various sensor subsystems 122, 122a-122d, configured to acquire sensor data 123, 123a-123d relating to properties of the environment 10 and / or the status of the vehicle 100. For example, the sensor subsystems 122 include an electronic power steering sensor subsystem 122a, configured to measure or receive front steering system data 123a, such as the angle of the front road wheels and / or the handwheel angle. The sensor subsystems 122 also include an active rear steering sensor subsystem 122b, configured to measure or receive rear steering data 123b, such as the angle of the rear road wheels. Furthermore, the sensor subsystems 122 may include an ADAS sensor subsystem 122c configured to measure or receive vehicle operating and / or vehicle position data 123c.The ADAS sensor subsystem 122c can include an inertial measurement unit (IMU) 124, one or more wheel speed sensors 125, one or more cameras 126, and other sensors for obtaining vehicle operating data 123c. The sensor subsystems 122 also include a vehicle exterior sensor subsystem 122d, configured to measure or obtain external environmental data 123d, such as weather or surrounding objects (e.g., vehicles, pedestrians). The vehicle exterior sensor subsystem 122d can include, for example, an RGB camera and / or an infrared camera and / or a thermal imaging camera and / or radar and / or an external microphone.

[0038] While the sensor system 120 collects the sensor data 123, the computer system 130 is configured to store, process, and / or transmit the sensor data 123 within the vehicle operating environment 10. To perform computer tasks related to the sensor data 123, the vehicle's computer system 130 includes data processing hardware 132 and storage hardware 134. The data processing hardware 132 is configured to execute instructions stored in the storage hardware 134 to perform computer tasks related to the operation and management of the vehicle 10. Generally speaking, the computer system 130 refers to one or more locations of the data processing hardware 132 and / or the storage hardware 134.

[0039] According to some examples, computer system 130 is a local system located in vehicle 100. When located in vehicle 100, computer system 130 can be centralized (i.e., in a single location / area within vehicle 100), decentralized (i.e., located in different locations within vehicle 100), or a hybrid combination of both (e.g., with a larger portion of centralized hardware and a smaller portion of decentralized hardware). To illustrate some differences, a decentralized computer system 130 can allow processing to take place at a single activity location, whereas a centralized computer system 130 can allow a central processing hub that communicates with systems located in different positions within vehicle 100.

[0040] Additionally or alternatively, computer system 130 contains computer resources located remotely from vehicle 100. For example, computer system 130 can communicate with a remote vehicle computer system 30 (e.g., a remote computer / server or a cloud-based environment) via network 40. Like computer system 130, the remote vehicle computer system 30 contains remote computer resources such as remote data processing hardware 32 and remote storage hardware 34. Sensor data 123 or other processed data (e.g., data processing performed locally by computer system 130) can be stored in the remote vehicle computer system 30 and accessed by computer system 130.According to some examples, computer system 130 is configured to use remote resources 32, 34 as extensions of computer resources 132, 134, so that resources of computer system 130 can reside in resources of remote vehicle computer system 30.

[0041] In Fig. 1 and Fig. 2 The vehicle management system 110 includes the advanced driver assistance system (ADAS) 140, which is capable of monitoring and controlling one or more electronic aspects of the vehicle 100. The ADAS 140 can monitor and control one or more subsystems of the vehicle 100. For example, as discussed in more detail below, the ADAS 140 can communicate with the steering controller 150 and with the EPS system 160 to maintain control of the vehicle 10. The ADAS can, for example, be configured to receive data from the active rear-wheel steering system and adjust the steering of the front wheels 104. According to at least one aspect of this disclosure, the ADAS 140 can include one or more modules for evaluating and / or storing sensor data 123 of the sensor system 120 and for providing instructions to one or more of the systems (e.g.,The ADAS 140 may include the steering controller 150 and the EPS system 160 of the vehicle 100 to maintain good trajectory adherence when the active rear-wheel steering system is enabled. For example, the ADAS 140 may include a trajectory planner 142 and a trajectory controller 144.

[0042] The motion path planner 142 and the motion path controller 144 can be configured to receive data 123, 123a-123d from one or more of the sensor subsystems 122, 122a-122d and to calculate a desired effective steering angle (i.e., a difference between the angle of the front road wheels and the angle of the rear road wheels) 146 based on a desired path. The desired effective steering angle 146 can be provided to the steering controller 150 so that a torque command 152 can be calculated for the EPS 160. In general, the EPS system 160 can receive the torque command 152 and adjust the road wheel angle of the front wheels 104 accordingly.

[0043] Continue in Fig. 1 and Fig. 2 The vehicle management system includes the ARS system 170, which can be configured to control the steering (i.e., the angle of the rear road wheels) of the rear wheels 106. Specifically, the ARS system 170 can control the steering of the rear wheels 106 independently. The ARS system 170 can be enabled or disabled via a feature state module 210 of the compensation module 200 of the active rear-wheel steering. In other words, a state signal 212 can be transmitted to lock or disable the ARS system 170.

[0044] Normally, when the ADAS system 140 is enabled during manual or automated driving scenarios, the ARS system 170 is disabled (i.e., the angle of the rear road wheels 106 is set to zero). According to at least one aspect of the present disclosure, the ARS compensation module 200 can be configured to receive data from the ARS system 170 and from the EPS system 160 so that the ARS system 170 can be selectively controlled while the ADAS 140 controls the vehicle 100 during automated or manual driving.

[0045] Continue in Fig. 2. The ARS compensation module 200 may further include a resolution upsampling module 220, a module 230 for the actual effective steering angle, and a module 240 for the error of the effective steering angle. In Fig. 3. The resolution upsampling module 220 can be configured to generate a high-resolution angle 221 of the rear road wheels. For example, the resolution upsampling module 220 can use a low-resolution measurement of the angle 222 of the rear road wheels, a measurement of a steering wheel angle (i.e., handwheel angle) 223, and a predictive ratio 224 to provide a high-resolution angle 221 of the rear road wheels. According to at least one aspect of the present disclosure, the low-resolution measurement of the angle 222 of the rear road wheels can be obtained from the sensor data 123b of the sensor subsystem 122b of the active rear-wheel steering, and the measurement of the steering wheel angle 223 can be obtained from the sensor data 123a of the subsystem 122a of the electronic power steering. The low-resolution measurement of the angle 222 of the rear road wheels can be evaluated by a detection module 225 to release a ratio estimation module 226.For example, the detection module 225 can evaluate the low-resolution measurement of the angle 222 of the rear road wheels to determine whether the data includes a rising edge, a positive value, a falling edge, and / or a negative value. The ratio estimation module 226 can evaluate the low-resolution measurement of the angle 222 of the rear road wheels and the measurement of the steering wheel angle 223 and provide the predictive ratio 224 for a resolution enhancement module 227. The resolution enhancement module 227 can take the predictive ratio 224 and the measurement of the steering wheel angle 223 into account and provide the high-resolution road wheel angle 221.

[0046] Back in Fig. Module 230 can evaluate an actual effective steering angle 232 by calculating the difference between either the measured low-resolution angle 222 of the rear road wheels or the high-resolution angle 221 of the rear road wheels and the measured angle of the front road wheels. The actual effective steering angle 232 can be provided to Module 240 for the effective steering angle error so that an effective steering angle error 242 can be calculated. The effective steering angle error 242 can be determined by calculating the difference between the desired effective steering angle 146 and the actual effective steering angle 232.

[0047] The error 242 of the effective steering angle can be provided to the steering controller 150 so that a set torque command 154 can be generated for the EPS system 160, which compensates for the ARS system 170.

[0048] In Fig. 4. A procedure 300 is provided for the lane centering control of the vehicle 100 equipped with the ARS system 170. At 310, the procedure 300 is initiated. In practical terms, the procedure 300 can be initiated by the operator switching on the vehicle 100.

[0049] At 320, the desired effective steering angle 146 can be determined based on the desired path of the vehicle 100. In other words, the motion path planner 142 of the ADAS 140 can be configured to provide the desired effective steering angle 146.

[0050] At 330, the angle of the front road wheels and the angle of the rear road wheels are measured. The angles of the front and rear road wheels can be acquired, for example, using one or more of the sensors of the ADAS sensor subsystem 122c and the active rear-wheel steering subsystem 122b. As discussed in more detail below, the measured angle 222 of the rear road wheels (i.e., a low-resolution angle of the rear road wheels) can be improved to the high-resolution road wheel angle 221.

[0051] At 340, the actual effective steering angle 232 can be determined for module 230. As stated above, the actual effective steering angle 232 can be determined by calculating the difference between either the measured low-resolution angle 222 of the rear road wheels or the high-resolution angle 221 of the rear road wheels and the measured angle of the front road wheels.

[0052] At 350, the effective steering angle error can be determined using module 240. Module 240 for effective steering angle error can be configured to calculate the difference between the desired effective steering angle (146) and the actual effective steering angle (232).

[0053] At 360°, the set torque command 154, which takes into account the error 242 of the effective steering angle, can be generated for the EPS system 160. In practical terms, the set torque command 154 takes into account the control of the ARS system 170 and can be received by the EPS to adjust the road wheel angle of the front wheels 104.

[0054] At 370, the ARS system 170 continues to control the angle of the rear road wheels 106 independently of the EPS system 160.

[0055] The process ends at 300 at 380.

[0056] In Fig. 5. A method 400 is provided for upsampling the low-resolution angle 222 of the rear road wheels to the high-resolution angle 221 of the rear road wheels. At 410, the method 400 is initiated. In practical terms, the method 400 can be performed simultaneously with the acquisition of the low-resolution road wheel angle 222 ( Fig. 3) initiated using one or more sensors of the sensor subsystem 122b of the active rear-wheel steering.

[0057] At 420, the detection module evaluates to 225 ( Fig. 3) The low-resolution road wheel angle 222 is output, and it can trigger and / or communicate with the ratio estimation module 226 if there is a rising edge, a positive value, a falling edge, and / or a negative value in the low-resolution angle 222 of the rear road wheels. According to another configuration, other values ​​or patterns can be used to trigger the ratio estimation module 226.

[0058] At 430, the ratio estimation module 226 can be configured to provide the predictive ratio 224. Generally, the predictive ratio 224 is an instantaneous ratio that takes into account the measured angle 222 of the rear road wheels and the steering wheel angle 223. A filtering gain is applied to the predictive ratio 224.

[0059] At 450, the resolution enhancement module 227 can be configured to instantaneously estimate the high-resolution angle 221 of the rear road wheels. According to one aspect, the high-resolution angle 221 of the rear road wheels can be estimated by forming the product of the predictive ratio 224 and the handwheel angle 223.

[0060] The high-resolution angle 221 of the rear road wheels can be used, for example, downstream by the steering controller 150. According to at least one configuration, a lookup table can be used to reinitialize the predictive ratio 224 if there is a significant change in vehicle speed since the ratio estimation module 226 was last triggered.

[0061] The process ends at 400 at 460.

[0062] In Fig. Section 6 provides a procedure 500 for dynamically controlling the state (i.e., enabled or disabled) of the ARS system 170. Procedure 500 may be desirable to maintain good trajectory tracking while the vehicle is traveling, for example, along a curve in the road. Procedure 500 is initiated at 510. In practical terms, procedure 500 can be initiated by the operator when the vehicle 100 is switched on.

[0063] At 520, the ARS system is enabled at 170. The active rear-wheel steering system can be activated or disabled when the vehicle is switched on at 100 or by the operator while the vehicle is stationary or traveling at low speed.

[0064] At step 530, the procedure transitions to step 500 and then to step 540 if one or more features of ADAS 140 are enabled. If one or more features of ADAS 140 are disabled, the procedure reverts to step 500 and then to step 520.

[0065] At 540, the procedure switches to 560 if the angle of the rear road wheels is less than a first threshold. If the angle of the rear road wheels is greater than a first threshold, the procedure switches to 550.

[0066] At 550, the procedure switches to 560 if the vehicle's speed is 100 less than a second threshold. If the vehicle's speed is 100 greater than the second threshold, the procedure reverts to 540 at 500.

[0067] At 560, the active rear-wheel steering system is deactivated (i.e., locked).

[0068] The process ends at 500 at 570.

[0069] The foregoing description is given for illustrative and descriptive purposes. Individual elements or features of a particular configuration are generally not limited to that specific configuration, but are, where applicable, interchangeable and can be used in a selected configuration, even if it is not specifically shown or described. Furthermore, it can be modified in many ways.

Claims

[1] Computer-implemented method (300) which, when executed by data processing hardware (132), causes the data processing hardware (132) to perform operations which include: Determining (320) a desired effective steering angle (146) based on a desired path of a vehicle (100); Measuring (330) an angle of the front road wheels and an angle of the rear road wheels; Determining (340) an actual effective steering angle (232); Determining (350) an error (242) of the effective steering angle based on the desired effective steering angle (146) and the actual effective steering angle (232); Generating (360) a torque command (154) for an electronic power steering system (160) based on the error (242) of the effective steering angle; Control (370) of an active rear-wheel steering system (170) independently of the electronic power steering system (160); and Adjusting the angle of the front road wheels of one or more front wheels (104) of the vehicle (100) on the basis of the torque command (154); characterized by , that the angle of the rear road wheels is a low-resolution angle (222) of the rear road wheels; wherein the method (300) further comprises measuring a handwheel angle (223); and wherein the method (300) further comprises estimating a high-resolution angle (221) of the rear road wheels using the low-resolution angle (222) of the rear road wheels, the handwheel angle (223) and a predictive ratio (224), wherein a filtering gain is applied to the predictive ratio (224). [2] Method (300) according to claim 1, wherein determining (340) the actual effective steering angle (232) further comprises evaluating a difference between the angle of the front road wheels and the high-resolution angle (221) of the rear road wheels. [3] Method (300) according to claim 1, wherein determining (340) the actual effective steering angle (232) further comprises evaluating a difference between the angle of the front road wheels and the angle of the rear road wheels. [4] Method (300) according to claim 1, wherein determining (350) the error (242) of the effective steering angle further comprises determining a difference between the desired effective steering angle (146) and the actual effective steering angle (232). [5] Method (300) according to claim 1, wherein the active rear-wheel steering system (170) is configured to be selectively controlled while an advanced driver assistance system (140) is enabled. [6] Method (300) according to claim 5, wherein the control (370) of the active rear-wheel steering system (170) further comprises deactivating the active rear-wheel steering system (170) if the advanced driver assistance system (140) is enabled and either: (i) an angle of the rear road wheels (160) is less than a first threshold or (ii) the vehicle (100) is traveling at a speed less than a second threshold.

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