Alternative control method for steering-by-wire system

Abstract

The invention relates to an alternative control method for a steer-by-wire system. A method for controlling a road wheel actuator (RWA) of a vehicle includes using one or more processors: determining an expected turning state of the vehicle by determining at least one of an expected yaw rate and an expected lateral acceleration of the vehicle; determining an actual turning state of the vehicle by determining at least one of an actual yaw rate and an actual lateral acceleration of the vehicle; determining a turn state error based on the expected turn state of the vehicle and the actual turn state of the vehicle; generating an RWA control signal based on the turn-over state error; and controlling at least one function of the vehicle using the RWA control signal.

Description

Technical Field

[0001] This disclosure relates to providing the driver with lateral control of a vehicle in response to a failure of a steer-by-wire (SbW) steering system. Background Technology

[0002] Vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transportation) typically include a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) system, a hydraulic steering system, or other suitable steering system. The steering system of such vehicles typically controls various aspects of the vehicle's steering, including providing steering assistance to the operator and controlling the steering wheels. Summary of the Invention

[0003] This disclosure generally relates to systems and methods configured to provide a driver with lateral control of a vehicle in response to a failure of a steer-by-wire (SbW) steering system.

[0004] One aspect of the disclosed embodiments includes a method for controlling a road wheel actuator (RWA) of a vehicle, the method comprising using one or more processors: determining a desired cornering state of the vehicle by determining at least one of a desired yaw rate and a desired lateral acceleration; determining an actual cornering state of the vehicle by determining at least one of an actual yaw rate and an actual lateral acceleration; determining a cornering state error based on the desired cornering state and the actual cornering state of the vehicle; generating an RWA control signal based on the cornering state error; and using the RWA control signal to control at least one function of the vehicle.

[0005] In another aspect, a system is configured to perform the functions of the various methods described herein. In yet another aspect, a processor is configured to execute instructions stored in memory to perform the functions of the various methods described herein.

[0006] Other applicable areas of this disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0007] This disclosure is best understood in conjunction with the accompanying drawings, based on the following description. It should be emphasized that, in accordance with conventional practice, the various features in the drawings are not necessarily drawn to scale. Instead, for clarity, the dimensions of the various features have been arbitrarily enlarged or reduced.

[0008] Figure 1A A vehicle based on the principles of this disclosure is shown in general.

[0009] Figure 1B A controller based on the principles of this disclosure is shown in general.

[0010] Figure 2A An example rack or RWA controller and column or steering wheel actuator (HWA) configured to perform RWA control according to the principles of this disclosure are generally shown.

[0011] Figure 2B An example of an RWA control computing system based on the principles of this disclosure is shown in general.

[0012] Figure 3 This is a flowchart that generally illustrates a method for performing RWA control according to the principles of this disclosure. Detailed Implementation

[0013] The following discussion pertains to various embodiments of this disclosure. While one or more of these embodiments may be preferred, the disclosed embodiments should not be construed as or otherwise intended to limit the scope of this disclosure (including the claims). Furthermore, those skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is merely illustrative and not intended to imply that the scope of this disclosure (including the claims) is limited to that embodiment.

[0014] As described, vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transportation) typically include a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) system, a hydraulic steering system, or other suitable steering system. The steering system of such vehicles typically controls various aspects of the vehicle's steering, including providing steering assistance to the vehicle's operator, controlling the vehicle's steering wheels, etc.

[0015] The SbW steering system may include: at least one steering wheel actuator (HWA), such as a steering wheel, used by a driver to laterally control the vehicle; and at least one road wheel actuator (RWA) for controlling the steering axis of the vehicle and generating lateral movement of the vehicle in response to movement of the HWA. The SbW system may also include a controller, such as a domain controller, configured to store and execute control logic.

[0016] SbW systems offer several advantages over other types of steering systems, such as EPS steering. For example, SbW systems are not limited by the mechanical connection between HWA and RWA. Therefore, SbW systems can offer more efficient encapsulation, increased collision avoidance and cost savings, as well as improved interaction with autonomous driving and advanced driver assistance systems (and corresponding safety and performance benefits).

[0017] In SbW systems without mechanical, electrical, or software backups or mitigation strategies or technologies, the deactivation of SbW control can result in a loss of lateral control over the vehicle. Therefore, various mitigation techniques can be used to extend the operational capabilities of SbW and ensure that the driver maintains some lateral control over the vehicle in the event of an SbW system failure. These mitigation techniques may include redundant sensors, actuators, and communication paths; various degraded state control strategies within the SbW system; and alternative methods for lateral control (e.g., torque vectoring control methods for braking or powertrain systems such as brake steering (SbB) technology).

[0018] However, compared to a fully operational SbW system, degraded states and other mitigation techniques typically offer less lateral control capability for vehicles. Furthermore, these mitigation techniques provide different levels of lateral control capability relative to each other.

[0019] Therefore, the SbW systems and methods according to this disclosure (e.g., RWA control systems and methods) are configured to provide increased control capabilities during the implementation of one or more mitigation / control techniques, and to extend the capabilities and operational use cases of these techniques. As an example, these systems and methods are configured to provide lateral control of the vehicle to the driver in the absence of feedback or control from the RWA or RWA sensors. As an example, the systems and methods of this disclosure are configured to generate RWA control signals to control the RWA in response to determining that one or more of the RWA controller, rack position controller, etc., are not controlling the rack position in a manner consistent with the driver's intention. The RWA control techniques of this disclosure strategy can be used to extend the operational use cases of SbW systems and reduce the likelihood of needing to rely on motion control strategies with capabilities lower than those of the RWA control system.

[0020] Figure 1AA vehicle 10 based on the principles of this disclosure is generally shown. Vehicle 10 may include any suitable vehicle, such as a car, truck, SUV, minivan, crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although vehicle 10 is shown as a wheeled passenger vehicle intended for use on a road, the principles of this disclosure can be applied to other vehicles, such as airplanes, ships, trains, drones, or other suitable vehicles.

[0021] Vehicle 10 includes a vehicle body (body, fuselage) 12 and a hood 14. A passenger compartment 18 is defined at least partially by the vehicle body 12. Another portion of the vehicle body 12 defines an engine compartment 20. The hood 14 may be movably attached to a portion of the vehicle body 12 such that when the hood 14 is in a first position or open position, the hood 14 provides access to the engine compartment 20, and when the hood 14 is in a second position or closed position, the hood 14 covers the engine compartment 20. In some embodiments, the engine compartment 20 may be located at the rear of the vehicle 10, rather than as generally shown.

[0022] The passenger compartment 18 may be located behind the engine compartment 20, but in embodiments where the engine compartment 20 is located at the rear of the vehicle 10, the passenger compartment may be located in front 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., for an electric vehicle), one or more fuel cells, a hybrid propulsion system including a combination of an internal combustion engine and one or more electric motors (e.g., for a hybrid vehicle), and / or any other suitable propulsion system.

[0023] In some embodiments, vehicle 10 may include a petroleum (UK) or gasoline (US) fuel engine, such as a spark-ignition engine. In some embodiments, vehicle 10 may include a diesel fuel engine, such as a compression-ignition engine. Engine compartment 20 houses and / or encloses at least some components of the propulsion system of vehicle 10. Additionally or alternatively, propulsion controllers (such as accelerator actuators (e.g., accelerator pedal), brake actuators (e.g., brake pedal), steering wheel, and other such components) are disposed in passenger compartment 18 of vehicle 10. The propulsion controllers may be actuated or controlled by the operator of vehicle 10 and may be directly connected to corresponding components of the propulsion system, such as throttle, brakes, vehicle axles, vehicle transmission, etc. In some embodiments, the propulsion controllers may transmit signals to a vehicle computer (e.g., drive-by-wire), which in turn may control the corresponding propulsion components of the propulsion system. Thus, in some embodiments, vehicle 10 may be an autonomous vehicle.

[0024] In some embodiments, the vehicle 10 includes a transmission connected to the crankshaft via a flywheel, clutch, or hydraulic coupler. 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 hybrid vehicle, the vehicle 10 may include one or more pistons that operate in cooperation with the crankshaft to generate force, which is transmitted via the transmission to one or more shafts that rotate the wheel 22. When the vehicle 10 includes one or more electric motors, a vehicle battery and / or fuel cell provide power to these electric motors to rotate the wheel 22.

[0025] Vehicle 10 may include an autonomous vehicle propulsion system, such as cruise control, adaptive cruise control, automatic braking control, other autonomous vehicle propulsion systems, or combinations thereof. Vehicle 10 may be an autonomous or semi-autonomous vehicle, or other suitable type of vehicle. Vehicle 10 may include more or fewer features than those generally shown and / or disclosed herein.

[0026] In some embodiments, vehicle 10 may include an Ethernet component 24, a Controller Area Network (CAN) bus 26, a Media-Oriented System Transport (MOST) component 28, a FlexRay component 30 (e.g., a brake-by-wire system), and a Local Interconnect Network (LIN) component 32. Vehicle 10 may use the CAN bus 26, MOST 28, FlexRay component 30, LIN 32, other suitable network or communication systems, or combinations 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. Vehicle 10 may include more or fewer features than those generally shown and / or disclosed herein.

[0027] In some embodiments, the vehicle 10 may include a steering system, such as an EPS system, a steer-by-wire system (e.g., which may include one or more controllers or communicate with the one or more controllers, which control components of the steering system without using a mechanical connection between the steering wheel and the wheel 22 of the vehicle 10), a hydraulic steering system (e.g., which may include a magnetic actuator incorporated into a valve assembly of a hydraulic steering system), or other suitable steering systems.

[0028] 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, position of one or more road wheels, other suitable inputs or information, or a combination thereof.

[0029] Additionally or alternatively, these inputs 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 auxiliary torque based on various inputs. The steering system may be configured to use the auxiliary torque to selectively control the steering system motor to provide steering assistance to the operator of the vehicle 10.

[0030] In some embodiments, the vehicle 10 includes one or more controllers, such as Figure 1BThe controller 100 is generally shown in the diagram. Controller 100 may correspond to a steering system controller. Controller 100 may include any suitable controller, such as an electronic control unit or other suitable controller. Controller 100 may be configured to control various functions, such as those of the steering system and / or various functions of the vehicle 10. Controller 100 may include a processor 102 and a memory 104. Processor 102 may include any suitable processor, such as the processor described herein. Additionally or alternatively, controller 100 may include any suitable number of processors as a complement to or alternative to processor 102. Memory 104 may include a single disk or multiple disks (e.g., a hard disk drive) and includes a storage management module that manages one or more partitions within memory 104. In some embodiments, memory 104 may include flash memory, semiconductor (solid-state) memory, etc. Memory 104 may include random access memory (RAM), read-only memory (ROM), or a combination thereof. Memory 104 may include instructions that, when executed by processor 102, cause processor 102 to control at least various aspects of vehicle 10. 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.

[0031] The controller 100 may receive one or more signals from various measuring devices or sensors 106 indicating sensed or measured characteristics of the vehicle 10. Sensors 106 may include any suitable sensors, measuring devices, and / or other suitable mechanisms. For example, 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.

[0032] As used herein, "controller" can refer to a hardware module or component including one or more processors or microcontrollers, memory, sensors, one or more actuators, communication interfaces, etc., any part of which can be collectively referred to as "circuit". As described herein, the corresponding functions and steps performed by a given controller, control circuit, etc., can be performed jointly by multiple controllers, processors, etc. For example, "configured to perform" can mean that a single processor, processing device, controller, etc., is configured to perform both A and B, or it can mean that a first processor, processing device, controller, etc., is configured to perform A, and a second processor, processing device, controller, etc., is configured to perform B. For simplicity, "control circuit configured to perform A and B" can mean that one or more processors, processing devices, controllers, etc., are jointly configured to perform A and B.

[0033] In some embodiments, controller 100 may perform the methods described herein. However, the methods described herein, as performed by controller 100, are not intended to be limited, and any type of software executed on the controller, processor, or other circuitry may implement the hysteresis shaping techniques described herein without departing from the scope of this disclosure. For example, a controller (such as a processor that executes software within a computing device) may implement the systems and methods described herein.

[0034] Systems and methods based on the principles of this disclosure (e.g., RWA control systems and methods) include, provide, and / or implement: an SbW vehicle model configured to determine the expected cornering state of the vehicle; calculation of the error between the expected cornering state and the actual cornering state (cornering state error); and calculation of RWA control signals for directly controlling the RWA (i.e., rather than providing control of the RWA via an RWA controller, rack and pinion position controller, etc.). For example, the SbW vehicle model may include one or both of an SbW model and a vehicle model (e.g., a vehicle model of various types, such as a bicycle model, a dual-track model, etc.).

[0035] The SbW vehicle model receives vehicle signals as input, such as vehicle speed, wheel speed, wheel or axle torque or force, etc. The SbW vehicle model also receives driver intention signals from the HWA, indicating the driver's expected lateral control actions, such as steering wheel or column angle, steering wheel or column torque, etc. The SbW vehicle model calculates and outputs the expected cornering state of the SbW vehicle, such as expected yaw rate, yaw acceleration, lateral acceleration, lateral velocity, etc.

[0036] To calculate cornering state errors, the expected cornering state can be compared with the actual cornering state (such as that obtained based on the output from vehicle sensors) to calculate and output cornering state errors, such as yaw rate error, yaw acceleration error, lateral acceleration error, and lateral velocity error.

[0037] To calculate the RWA control signal, a controller, control module, or control circuit, a processor configured to perform the functions described below, etc. (e.g., a closed-loop controller, such as a PID controller), receives the cornering state error and calculates the RWA control signal based on the cornering state error (and in some examples, one or more other vehicle signals, such as vehicle speed, torque, etc.). The RWA control signal may include control parameters, including but not limited to motor torque, motor current, and / or motor voltage (e.g., actuators of the SbW steering system or steering rack and / or other components of the motor). The RWA control signal corresponds to a target output (e.g., a target rack position), which is provided to the motor controller associated with the RWA and / or directly to the RWA motor to generate a force to move the steering axis and cause lateral movement of the vehicle.

[0038] Previous techniques for determining the state of the motion control strategy for the current operation typically rely on sensors and states within the RWA. However, in these examples, if the position sensor of the steering rack is used to provide feedback from the RWA to determine whether RWA control causes rack movement, the failure of that position sensor may render RWA control of the rack (steering rack) no longer feasible. In another example, if the RWA stops communicating with the HWA or domain controller, some methods may determine that RWA control of the rack is no longer feasible. However, in both examples, RWA control of the rack remains feasible (e.g., using open-loop strategies, vehicle-level feedback strategies, etc.).

[0039] As an example, the systems and methods according to this disclosure are configured to implement control strategies to calculate RWA control signals in a manner that mitigates or compensates for RWA position sensor failure or communication failure between the RWA and HWA, domain controllers, etc. More specifically, the described systems and methods are configured to control the RWA based on driver intent by comparing the vehicle's expected cornering state with the vehicle's actual cornering state.

[0040] Figure 2AAn example rack or RWA controller 200 and column or steering wheel actuator (HWA) controller 204 configured to implement RWA control technology in a steering system according to this disclosure are shown. 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) received from the RWA controller 200 and one or more other input signals (e.g., vehicle speed, steering wheel position, and steering wheel speed). The RWA controller 200 is configured to determine the estimated rack force based on the motor torque required to achieve or maintain the actual rack position. Controllers 200 and 204 may correspond to, be implemented by, or correspond to one or more steering system controllers.

[0041] As an example, the HWA controller 204 includes a reference torque calculator 208 configured to calculate a reference torque (Tref) based on an estimated rack force and one or more other input signals. For example, the reference torque corresponds to the sum of various inputs / measurements such as applied force, hysteresis, return correction, damping, catch, 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 the force or torque applied by the driver (e.g., “Tbar torque”) and the reference torque. The motor torque command is provided as a control signal to control the motor of the steering wheel actuator.

[0042] The estimated rack force corresponds to the measured or estimated torque of the road wheel actuator motor. Therefore, the estimated rack force (and any estimated rack force offset or error) is a critical factor in determining the force provided by the motor of the steering wheel actuator.

[0043] 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 a 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 the driver’s intention conveyed via the steering wheel). An example system and method for obtaining a rack position reference and a C-factor are described in more detail in U.S. Patent Application No. 18 / 318,657, filed May 16, 2023, the entire contents of which are incorporated herein by reference.

[0044] RWA controller 200 includes rack position controller 224 (e.g., PID rack position controller) configured to generate one or more rack position control signals based on the actual rack position and a rack position reference (e.g., based on the 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 commands (e.g., signals indicating the amount of torque applied by the driver). In this way, the rack position is controlled to follow the driver's intention (as indicated by the rack reference position).

[0045] 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 rack motor torque command, a function of the rack motor speed, etc.). In various examples, the estimated rack force may be calculated based on the amount of torque applied to the steering wheel by the driver (e.g., indicated by a rack motor torque command, various sensor signals, etc.). As shown, the rack force predictor 228 may output the estimated rack force, and a reference torque calculator 208 (and / or another component of the HWA controller 204, RWA controller 200, etc.) may obtain an estimated rack load based on this estimated rack force. In other examples, the rack force predictor 228 may output the estimated rack load. In some cases, the terms "estimated rack force" and "estimated rack load" may be used interchangeably.

[0046] For example, for RWA position control, the rack position reference signal (“RackPosRef”) can be calculated based on the position error (“PosErr”) between the ADAS rack position reference value or signal (“ADASRackPosRef”) and the HWA rack position reference value or signal (“HWARackPosRef”). Conversely, HWA position control is based on the position error between the HWA position and the RWA position, allowing the steering wheel to be controlled to rotate in a manner consistent with the rotation of the road wheels when hands-off (without interference).

[0047] The reference torque can correspond to the desired, ideal, or target torque that the driver (i.e., at the 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 steering wheel angle), road conditions, damping, hysteresis, etc. The torque at the steering wheel (e.g., via HWA) is controlled to match the reference torque. For example, the outputs of one or more sensors measuring the actual torque at the wheels are used to minimize the difference between the reference torque and the actual torque.

[0048] A force function (e.g., a force function implemented by the reference torque calculator 208) defines the relationship between driver input (e.g., the force or torque applied by the driver to the steering wheel, which may be referred to as "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 input). The estimated rack load may be modified before being input into the lookup table by adding the calculated return load value to the estimated rack load. The force function indicates the amount of force required by the driver to elicit the desired response.

[0049] The HWA controller 204 according to this disclosure includes an RWA control calculation system 230, which is configured to: determine the expected cornering state of a vehicle; compare the expected cornering state with the actual cornering state; calculate the error between the expected cornering state and the actual cornering state; and selectively generate signals based on the cornering state error to control the steering of the vehicle.

[0050] For example, the RWA control computing system 230 can generate and output an RWA control signal 232 configured to control rack position, road wheel, etc. The RWA control signal 232 is separate from / different from the RWA control signal generated by or within the RWA controller 200. For example, as described above, the RWA controller 200 includes a rack position controller 224 configured to generate one or more rack position control signals to control rack motor speed, motor torque, etc. As shown, the rack position control signal can be represented by one or more motor control signals 234 provided to a motor, actuator, etc. (such as rack motor 236) associated with controlling the rack position. For example, the rack position controller 224 (e.g., a motor controller implemented by or responding to the rack position controller 224) is configured to generate motor control signals 234 to control the rack motor 236, thereby achieving the desired movement / position of the steering rack.

[0051] Even when the RWA controller 200, rack position controller 224, etc., do not control the rack motor 236, the RWA control calculation system 230 according to this disclosure provides an RWA control signal 232 to control the rack motor 236. For example, the failure of the RWA controller 200 to control the rack motor 236 may not necessarily indicate that the rack motor 236 itself, the rack, etc., cannot be operated to control the vehicle's steering. Rather, the failure to control the rack motor 236 may be caused by the failure of one or more sensors associated with the RWA controller, or by a failure of communication between or to and from the various components of the RWA controller 200 (such as communication to and from the HWA controller 204 and / or another controller). Therefore, in these examples, RWA control of the rack motor 236 is still feasible / possible according to the principles of this disclosure.

[0052] More specifically, the RWA control signal 232 (generated externally to the RWA controller 200) is configured to replace or supersede the motor control signal generated by / within the rack position controller 224. For example, the RWA control system 230 generates the RWA control signal 232 to control the rack motor 236 in response to determining that the RWA controller 200 is not effectively controlling the rack motor 236.

[0053] For example, RWA control signal 232 is configured to control motor torque, current, voltage, etc., based on steering wheel position / angle and / or other vehicle signals to achieve a desired (e.g., as indicated by driver intent) rack position / movement. Rack position controller 224 (e.g., a motor controller, which may be located external to rack position controller 224, external to RWA controller 200, etc.) receives RWA control signal 232, and motor control signal 234 is generated based on RWA control signal 232. For example, RWA control signal 232 may include instructions or commands used to generate motor control signals instead of using internal rack position controller calculations. In some examples, RWA control signal may correspond to motor control signal and may be provided directly from RWA control calculation system 230 to rack motor 236.

[0054] Although shown as being included within the HWA controller 204, some or all of the functions of the RWA control computing system 230 may be located and / or implemented by other components of the vehicle, such as domain controllers, ECUs, etc.

[0055] Figure 2BAn example of an RWA control calculation system 230 according to the principles of this disclosure is shown in more detail. By way of example only, the RWA control calculation system 230 may include and / or implement one or more computing devices, controllers, circuits, etc., configured to perform the functions of the components described below. As shown, the RWA control calculation system 230 includes an SbW vehicle model 238, an error calculation module 240, and an RWA control signal calculation module 242.

[0056] The SbW vehicle model 238 is configured to calculate or determine the vehicle's expected cornering state based on one or more inputs indicating the driver's intention. For example, the driver intention may correspond to a driver's steering or lateral movement intention, such as that indicated by steering wheel movement, which may be referred to as the HWA driver intention. Figure 2B As shown, the HWA driver intent is indicated by the HWA driver intent signal, which may include one or more of the HW (or column) angle and HW (or column) torque. Other input signals include, but are not limited to, vehicle signals (such as vehicle speed and torque, wheel speed, wheel or axle torque or force, etc.).

[0057] The SbW vehicle model 238 is configured to calculate and output the expected cornering state based on the HWA driver intention signal and / or, in some examples, based on vehicle signals. For example, the expected cornering state may include, or otherwise indicate, the vehicle's expected yaw rate, expected yaw acceleration, expected lateral acceleration, expected lateral velocity, etc. In other words, the SbW vehicle model 238 is configured to determine one or more expected conditions of the vehicle (e.g., as expected in response to driver / HW input).

[0058] Error calculation module 240 is configured to calculate or determine a cornering state error based on the expected cornering state and the actual cornering state. For example, the actual cornering state may be obtained based on one or more various signals (such as signals obtained from corresponding sensors, calculations, etc.) indicating the actual vehicle condition. As an example, the actual cornering state may be calculated based on the vehicle's actual yaw rate, actual yaw acceleration, actual lateral acceleration, actual lateral velocity, etc. Error calculation module 240 compares the expected cornering state with the actual cornering state and calculates and outputs the cornering state error based on the difference between the expected and actual cornering states. The cornering state error may include or indicate only a single error value (e.g., yaw rate error or lateral acceleration error) or multiple error values ​​(e.g., both yaw rate error and lateral acceleration error). In some examples, the cornering state error may correspond to a combination of error values ​​(e.g., the average of the yaw rate error and the lateral acceleration error).

[0059] RWA control signal calculation module 242 is configured to calculate / generate RWA control signal 232 based on cornering state error and one or more other vehicle signals (such as steering wheel position / angle and / or other signals indicating driver intent). For example, RWA control signal 232 is configured to control motor torque, current, voltage, etc., to achieve a desired (e.g., as indicated by driver intent) rack position / movement. As an example, RWA control signal calculation module 242 compares RWA control signal 232 with a cornering error threshold and generates RWA control signal 232 in response to exceeding the cornering error threshold.

[0060] In this way, the RWA control signal calculation module 242 is configured to generate an RWA control signal 232 in response to determining that the rack motor 236 is not responding to the RWA controller 200, to control the rack position / movement (e.g., by controlling the rack motor 236).

[0061] Figure 3 This is a flowchart generally illustrating a method 300 for performing RWA control according to the principles of this disclosure. For example, one or more computing devices, processors, or processing devices are configured to execute instructions to implement method 300, such as one or more processors in a system described herein (e.g., a computing device or processor of a vehicle configured to implement controller 100, RWA control computing system 230, etc.). In some examples, one or more steps in the steps of method 300 described below may be skipped or omitted, and / or one or more of these steps may be performed in a different order than described.

[0062] At 304, method 300 includes determining the expected cornering state of the vehicle. At 308, method 300 includes determining the actual cornering state of the vehicle. At 312, method 300 includes determining a cornering state error based on the expected cornering state and the actual cornering state.

[0063] At 316, method 300 includes determining a RWA control signal based on cornering state error and driver intent. In one example, determining the RWA control signal includes generating an RWA control signal in response to a cornering state error exceeding a threshold, and the RWA control signal instructing target motor voltage, current, torque, etc., according to the driver intent.

[0064] At 320, method 300 includes controlling at least one vehicle function based on an RWA control signal. For example, controlling at least one vehicle function may include, but is not limited to, one or more of the following: controlling the lateral movement / steering of the vehicle by controlling a rack and pinion motor based on an RWA control signal.

[0065] The foregoing discussion is intended to illustrate the principles and various embodiments of the invention. Many variations and modifications will become apparent to those skilled in the art once the foregoing disclosure is fully understood. The appended claims are intended to be construed as covering all such variations and modifications.

[0066] The word “example” is used herein to indicate that something is used as an example, instance, or illustration. No aspect or design described herein as an “example” is necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, the use of the word “example” is intended to present the concept in a specific manner. As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or clearly understood from the context, “X comprises A or B” is intended to mean any of the natural inclusive permutations and combinations. That is, if X comprises A; X comprises B; or X comprises both A and B, then “X comprises A or B” is satisfied in any of the foregoing examples. Additionally, the articles “a” and “an” as used herein and in the appended claims should generally be interpreted as meaning “one or more” unless otherwise specified or clearly understood from the context to refer to the singular form. Furthermore, the use of the terms “one embodiment” or “an embodiment” throughout is not intended to refer to the same embodiment or implementation unless specifically described as such.

[0067] The systems, algorithms, methods, instructions, etc., described herein can be implemented in hardware, software, or any combination thereof. Hardware may include, for example, computers, intellectual property (IP) cores, application-specific integrated circuits (ASICs), programmable logic arrays, optical processors, programmable logic controllers, microcode, microcontrollers, servers, microprocessors, digital signal processors, or any other suitable circuitry. In the claims, the term "processor" should be understood to cover any of the aforementioned hardware, individually or in combination. The terms "signal" and "data" are used interchangeably.

[0068] As used herein, the term "module" can include packaged functional hardware units designed for use with other components, instruction sets executable by a controller (e.g., a processor executing software or firmware), processing circuitry configured to perform specific functions, and stand-alone hardware or software components that interface with a larger system. For example, a module can include application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), circuits, digital logic circuits, analog circuits, combinations of discrete circuits, gates, and other types of hardware, or combinations thereof. In other embodiments, a module can include memory storing instructions that can be executed by a controller to implement the features of the module.

[0069] Furthermore, in one aspect, for example, the system described herein can be implemented using a general-purpose computer or general-purpose processor having a computer program that, when executed, implements any of the various methods, algorithms, and / or instructions described herein. Alternatively or additionally, for example, a special-purpose computer / processor may be utilized, which may include additional hardware for implementing any of the methods, algorithms, or instructions described herein.

[0070] Furthermore, all or part of the embodiments of this 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 means capable of, for example, tangibly containing, storing, transmitting, or transporting a program for use by or in conjunction with any processor. Such a medium may be, for example, an electronic, magnetic, optical, electromagnetic, or semiconductor device. Other suitable media are also available.

[0071] The above embodiments, implementations, and aspects have been described to allow for an easy understanding of the invention and are not intended to limit it. Rather, the invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which should be given the broadest interpretation to cover all such modifications and equivalent structures permitted under the law.

Claims

1. A method for controlling a road wheel actuator (RWA) of a vehicle, the method comprising using one or more processors: Determine the expected cornering state of the vehicle, wherein, Determining the expected cornering state includes determining at least one of the expected yaw rate and the expected lateral acceleration of the vehicle; Determine the actual cornering state of the vehicle, wherein determining the actual cornering state includes determining at least one of the actual yaw rate and actual lateral acceleration of the vehicle; The cornering error is determined based on the expected cornering state of the vehicle and the actual cornering state of the vehicle. Based on the cornering state error, a road wheel actuator control signal is generated; and The road wheel actuator control signal is used to control at least one function of the vehicle.

2. The method according to claim 1, wherein, Determining the expected cornering state of the vehicle includes using a steer-by-wire vehicle model to obtain the expected cornering state based on one or more instructions from the driver's intention.

3. The method according to claim 2, wherein, One or more indications of the driver's intent include at least one of steering wheel angle and steering wheel torque.

4. The method according to claim 3, wherein, Obtaining the expected cornering state includes obtaining the expected cornering state based on at least one of vehicle speed, wheel speed, axle torque, braking torque, and wheel torque.

5. The method according to claim 1, wherein, Determining the cornering state error includes determining the cornering state error based on the difference between the expected cornering state of the vehicle and the actual cornering state of the vehicle.

6. The method according to claim 1, wherein, Generating the road wheel actuator control signal includes generating the road wheel actuator control signal based on one or more signals indicating the driver's intention.

7. The method of claim 1, further comprising using the road wheel actuator control signal to control the rack motor to control the lateral movement of the vehicle.

8. The method according to claim 7, wherein, Generating the road wheel actuator control signal includes generating the road wheel actuator control signal at a location inside the vehicle and outside the road wheel actuator controller.

9. A system for controlling a road wheel actuator (RWA) of a vehicle, the system comprising: One or more sensors are configured to determine one or more operating characteristics of a vehicle; and A processor is configured to execute instructions stored in memory, wherein executing the instructions causes the processor to: Determining the expected cornering state of the vehicle, wherein determining the expected cornering state includes determining at least one of the expected yaw rate and expected lateral acceleration of the vehicle. The actual cornering state of the vehicle is determined based on one or more of the aforementioned operating characteristics, wherein determining the actual cornering state includes determining at least one of the vehicle's actual yaw rate and actual lateral acceleration. The cornering error is determined based on the expected cornering state of the vehicle and the actual cornering state of the vehicle. Based on the cornering state error, a road wheel actuator control signal is generated, and The road wheel actuator control signal is used to control at least one function of the vehicle.

10. The system according to claim 9, wherein, Determining the expected cornering state of the vehicle includes using a steer-by-wire vehicle model to obtain the expected cornering state based on one or more instructions from the driver's intention.

11. The system according to claim 10, wherein, One or more indications of the driver's intent include at least one of steering wheel angle and steering wheel torque.

12. The system according to claim 11, wherein, Obtaining the expected cornering state includes obtaining the expected cornering state based on at least one of vehicle speed, wheel speed, axle torque, braking torque, wheel torque, and vehicle torque.

13. The system according to claim 9, wherein, Determining the cornering state error includes determining the cornering state error based on the difference between the expected cornering state of the vehicle and the actual cornering state of the vehicle.

14. The system according to claim 9, wherein, Generating the road wheel actuator control signal includes generating the road wheel actuator control signal based on one or more signals indicating the driver's intention.

15. The system of claim 9 further includes using the road wheel actuator control signal to control the rack motor to control the lateral movement of the vehicle.

16. The system according to claim 15, wherein, Generating the road wheel actuator control signal includes generating the road wheel actuator control signal at a location inside the vehicle and outside the road wheel actuator controller.

17. A system for controlling a road wheel actuator (RWA) of a vehicle, the system comprising: The processor is configured to use a steer-by-wire vehicle model to determine the expected cornering state of the vehicle, wherein determining the expected cornering state includes determining at least one of the expected yaw rate and the expected lateral acceleration of the vehicle. An error calculation module is configured to determine a cornering state error based on the expected cornering state of the vehicle and the actual cornering state of the vehicle, wherein the actual cornering state of the vehicle is based on at least one of the vehicle's actual yaw rate and actual lateral acceleration; and The road wheel actuator control signal calculation module is configured to generate and output the road wheel actuator control signal based on the cornering state error.

18. The system of claim 17, further comprising a rack motor configured to control lateral movement of the vehicle, wherein, The road wheel actuator control signal calculation module is configured to use the road wheel actuator control signal to control the rack motor.

19. The system according to claim 17, wherein, Determining the expected cornering state of the vehicle includes using a steer-by-wire vehicle model to obtain the expected cornering state based on one or more instructions from the driver's intention.

20. The system according to claim 19, wherein, One or more indications of the driver's intent include at least one of steering wheel angle and steering wheel torque.

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