COLLABORATIVE STEERING IN STEER-BY-WIRE SYSTEMS FOR AUTOMATED DRIVING

Abstract

A collaborative steering system in steer-by-wire (SBW) vehicles includes sensors, a rack motor that changes the position of the vehicle's steerable road wheels, and an emulator that changes the torque and position of a vehicle handwheel. A collaborative steering system application (CSSA) receives static and dynamic information about the vehicle and its surroundings and generates a rack torque and / or rack angle command for the rack motor and an emulator torque and / or angle command for the emulator. The CSSA adjusts between an ADAS steering ratio and a manual steering ratio and automatically switches between ADAS SBW control and manual control.The CSSA smooths transitions between the ADAS SBW control and the manual steering control, adjusts the handwheel stiffness by changing the emulator torque command, and causes the rack motor and emulator to operate according to a kinematic model while adjusting the road wheel response and driver steering feel based on currently enabled scenarios and features.

Description

INTRODUCTION

[0001] The present disclosure relates to steering systems in vehicles, and more particularly to electronic power steering (EPS) systems utilizing steer-by-wire (SBW) in such vehicles. SBW systems are the successors to conventional manual, hydraulic, and electric steering systems for motor vehicles. However, in SBW systems, there is no mechanical connection between the steering wheel and the rack and the steerable wheels. Such systems primarily consist of two elements: an idler wheel actuator for adjusting the idler wheel angle and a steering wheel actuator that can impart steering effort or feel.The absence of a steering column and the indirect feedback torque to the steering wheel provided by the steering wheel actuator can result in altered or missing feedback torque related to vehicle dynamics, including acceleration, deceleration, lateral acceleration, and the like, since such movements only directly affect the idler wheel actuator. Furthermore, conventional SBW systems can cause driver / operator confusion or discomfort due to inconsistent responses of the idler wheel actuator to steering wheel movement and steering wheel actuator movement, creating a sense of disconnection between the steering wheel and the steerable idler wheels.

[0002] Accordingly, although current SBW systems and methods serve their intended purpose, there is a need in the art for new and improved SBW systems and methods that can be used with automated driving systems and that improve operator comfort, increase a sense of connectedness between the movements of the wheels and the steering wheel, and enable effective and smooth transitions between autonomous driving and manual steering movements, while maintaining or reducing the complexity of the system components and providing redundancy, and that can be applied to new vehicles or retrofitted into existing vehicles with suitable hardware. SUMMARY

[0003] According to several aspects of the present disclosure, a system for collaborative steering in steer-by-wire (SBW)-equipped vehicles includes a vehicle and one or more sensors mounted on the vehicle that collect static and dynamic information about the vehicle and an environment surrounding the vehicle. The system further includes a rack and pinion motor disposed on a steering rack of the vehicle, the rack and pinion motor selectively adjusting an angular position of one or more steerable road wheels of the vehicle. A steering emulator is connected to a handwheel of the vehicle and selectively generates torque and adjusts an angular position of the handwheel. The steering emulator and the rack and pinion motor are in electronic communication with each other. The system further includes a controller having a processor, memory, and one or more input / output (I / O) ports.The I / O ports communicate with the one or more sensors, the rack motor, and the steering emulator. The processor executes programmatic control logic stored in memory. The programmatic control logic includes a collaborative steering system application (CSSA). The CSSA includes at least first, second, third, fourth, fifth, sixth, and seventh control logic. The first control logic receives static and dynamic information about the vehicle and the vehicle's surroundings from one or more sensors, the steering emulator, and the rack motor. In response to the static and dynamic information, the second control logic generates one or more rack torque commands and rack angle commands for the rack motor and generates one or more emulator torque commands and emulator angle commands for the steering emulator.The third control logic determines a steering ratio between the angular movement of the steerable road wheels and the angular movement of the handwheel. The steering ratio is dynamically adjustable from at least one ADAS steering ratio to a manual steering ratio that differs from the ADAS steering ratio. The fourth control logic selectively and automatically switches the vehicle steering control between the automated driver assistance system (ADAS) SBW control and the manual steering control. The fifth control logic smooths transitions between the ADAS SBW control and the manual steering control. The sixth control logic automatically and dynamically adjusts a handwheel stiffness by changing the emulator torque command in response to data from one or more sensors and from the steering emulator and the rack and pinion motor.The seventh control logic coordinates a driver feedback control circuit with a trajectory tracking control circuit for ADAS and causes the rack motor and steering emulator to operate according to a kinematic model of a mechanical connection between the rack, handwheel, and steerable road wheels, while providing variable control gains that adjust road wheel response and driver steering feel based on the driving scenario and currently enabled driving functions.

[0004] According to another aspect of the present disclosure, the first control logic further includes control logic for obtaining static and dynamic information about the vehicle, including: a vehicle speed, a presence or absence of a trailer attached to the vehicle, a current road wheel angle, a current handwheel angle. The first control logic further includes control logic for obtaining information about the vehicle's surroundings, including: a topology of a road segment near the vehicle, a road type, a lane quality, a look-ahead curvature, current weather conditions, a field of view and a view distance of the one or more sensors, an object detection confidence, a lateral distance to surrounding vehicles, a magnitude of a lateral threat, a presence of an intersection, and a potential evasive steering maneuver.

[0005] According to another aspect of the present disclosure, the second control logic further includes control logic that determines a desired angle of steerable road wheels and communicates the rack torque and / or rack angle command to the rack motor. Upon receiving the rack torque and / or rack angle command, the rack motor generates a torque output that changes an angle of the steerable road wheels. The second control logic further determines a desired handwheel angle based in part on the angle of the steerable road wheels and a steering ratio at a current time step; and communicates the emulator torque and / or emulator angle command to the steering emulator. Upon receiving the emulator torque and / or emulator angle command, the steering emulator generates a torque output that changes an angle of the handwheel.

[0006] According to yet another aspect of the present disclosure, the third control logic dynamically adjusts the steering ratio in response to the static and dynamic information about the vehicle and the vehicle's surroundings.

[0007] According to yet another aspect of the present disclosure, the fourth control logic selectively and automatically switches the vehicle steering control between the automated driver assistance system (ADAS) SBW control and the manual steering control based on the static and dynamic information about the vehicle and the vehicle's surroundings, based on a currently active ADAS function, and based on a current manual override or hands-free operating state of the handwheel.

[0008] According to yet another aspect of the present disclosure, the manual or hands-free operating state of the handwheel is determined by a touch sensor that detects the presence and / or absence of a vehicle operator's hands on the handwheel. If it is determined that the vehicle is operating in a hands-free operating state, the system selectively activates a function escalation state that prompts the vehicle operator to assume control of the steering.

[0009] According to yet another aspect of the present disclosure, the fifth control logic smooths transitions between the ADAS SBW control and the manual steering control by maintaining feedback to the handwheel during assisted driving and controlling a timing and transition rate with a transition factor α. The transition factor α depends on the vehicle speed, the lane stability condition, and the time since the ADAS SBW control was turned off, such that: Ksteer=αKsteerNorm+(1−α)KsteerADAS; where α = f(vehicle speed, lane stability, time since ADAS intervention) ∈ [0, 1]; and δrwacmndnorm=δhwaKsteer, K steerADAS the ADAS steering ratio is defined as KsteerADAS=δhwaADASδrwacmndnorm is; K steerNorm the manual steering ratio is defined as KsteerNorm=δhwaδrwacmndnorm is; δ hwaADASis a handwheel angle commanded by ADAS, and δrwacmndADAS is an ADAS commanded wheel angle; δ hwa a handwheel angle commanded by the driver; δrwacmndnorm a wheel angle commanded by the driver.

[0010] According to yet another aspect of the present disclosure, the sixth control logic automatically and dynamically adjusts handwheel stiffness by adjusting the steering emulator torque outputs based on static and dynamic information about the vehicle and information about the vehicle's surroundings obtained within the first control logic, and based on the vehicle operator's attention levels, the vehicle operator's past preferences, the capability and availability of the ADAS SBW control trajectory tracking, including obstacles identified by the one or more sensors.The sixth control logic further identifies obstacles and prevents the vehicle operator from causing a collision of the vehicle with the obstacles, as well as assists the vehicle operator in navigating dynamic driving scenarios by dynamically adjusting a steering ratio gain and changing an effectiveness of the vehicle operator's inputs to the handwheel.

[0011] According to yet another aspect of the present disclosure, the seventh control logic includes collaborative steering feedback control logic that receives vehicle state information, steering commands, and steering characteristics and generates a handwheel torque overlay command. The handwheel torque overlay command is sent to the steering emulator and overlaid with torque inputs from the vehicle operator, and a coordinated desired steering angle command is sent to the rack and pinion motor. The handwheel torque overlay is defined as follows: Δτdf=f(τd,pd,ps,x˙,δ˙,δref,m)=kv δ˙×[αd(x˙,δ˙,δref)pd+αs(x˙,δ˙)ps] where τ d a handwheel torque applied by the driver; p d is a driver preference; p s is a trigger for adjusting the steering feel; δ is a measured wheel angle; e is a trajectory following error; x is a vehicle state; m is a steering performance mode; δ ref is a desired steering angle command; δ c is a wheel angle command; and k v is a variable gain.

[0012] According to yet another aspect of the present disclosure, a method for collaborative steering in steer-by-wire (SBW)-equipped vehicles comprises collecting static and dynamic information about the vehicle and an environment surrounding the vehicle with one or more sensors disposed on a vehicle with which the vehicle is equipped. The method further comprises selectively adjusting an angular position of one or more steerable road wheels of the vehicle with a rack and pinion motor disposed on a steering rack of the vehicle, and selectively generating torque and adjusting an angular position of a handwheel with a steering emulator connected to the handwheel of the vehicle, wherein the steering emulator and the rack and pinion motor are in electronic communication with each other.The method further includes executing programmatic control logic comprising a collaborative steering system application (CSSA) stored in a memory of a controller of the vehicle. The controller has a processor, the memory, and one or more input / output (I / O) ports. The I / O ports communicate with the one or more sensors and the rack motor and the steering emulator. The CSSA includes: obtaining static and dynamic information about the vehicle and the environment around the vehicle from one or more sensors and from the steering emulator and the rack motor, and generating one or more of a rack torque command and a rack angle command for the rack motor in response to the static and dynamic information, and generating one or more of an emulator torque and / or an emulator angle command for the steering emulator.The CSSA determines a steering ratio between the angular movement of the steerable road wheels and the angular movement of the handwheel. The steering ratio is dynamically adjustable from at least one ADAS steering ratio to a manual steering ratio that differs from the ADAS steering ratio. The CSSA automatically and selectively switches vehicle steering control between the automated driver assistance system's SBW control (ADAS SBW control) and manual steering control, smoothing transitions between ADAS SBW control and manual steering control. The CSSA automatically and dynamically adjusts handwheel stiffness by changing the emulator torque command in response to data from one or more sensors and from the steering emulator and rack motor.The CSSA coordinates a driver feedback control circuit with a trajectory tracking control circuit for ADAS and causes the rack motor and steering emulator to operate according to a kinematic model of a mechanical connection between the rack, handwheel, and steerable road wheels, while providing variable control gains that adjust road wheel response and driver steering feel based on the driving scenario and currently enabled driving functions.

[0013] According to yet another aspect of the present disclosure, the method obtains static and dynamic information about the vehicle, including: a vehicle speed, a presence or absence of a trailer attached to the vehicle, a current road wheel angle, a current hand wheel angle; and obtains information about the vehicle's surroundings, including: a topology of a road segment near the vehicle, a road type, a lane quality, a look-ahead curvature, current weather conditions, a field of view and a view distance of the one or more sensors, an object detection confidence, a lateral distance to surrounding vehicles, a magnitude of a lateral threat, a presence of an intersection, and a potential evasive steering maneuver.

[0014] According to yet another aspect of the present disclosure, the method further comprises determining a desired angle of the steerable road wheels and transmitting the rack torque and / or rack angle command to the rack motor. Upon receiving the rack torque and / or rack angle command, the rack motor generates a torque output that changes an angle of the steerable road wheels. The method further comprises determining a desired handwheel angle based in part on the angle of the steerable road wheels and a steering ratio at a current time step; and transmitting the emulator torque and / or emulator angle command to the steering emulator. Upon receiving the emulator torque and / or emulator angle command, the steering emulator generates a torque output that changes an angle of the handwheel.

[0015] According to yet another aspect of the present disclosure, the method further comprises dynamically adjusting the steering ratio in response to the static and dynamic information about the vehicle and the vehicle's surroundings.

[0016] According to yet another aspect of the present disclosure, the method further comprises selectively and automatically switching the vehicle steering control between the automated driver assistance system (ADAS) SBW control and the manual steering control based on the static and dynamic information about the vehicle and the vehicle's surroundings, based on a currently active ADAS function, and based on a current manual or hands-free operating state of the handwheel.

[0017] According to yet another aspect of the present disclosure, the method further includes determining the manual and hands-free operating states of the handwheel via a touch sensor that detects the presence and / or absence of a vehicle operator's hands on the handwheel. Upon determining that the vehicle is operating in a hands-free operating state, the system selectively activates a function escalation state that prompts the vehicle operator to assume control of the steering.

[0018] According to yet another aspect of the present disclosure, the method further comprises: smoothing transitions between the ADAS SBW control and the manual steering control by maintaining feedback to the handwheel during assisted driving and controlling a timing and a transition rate with a transition factor α. The transition factor α depends on the vehicle speed, the lane stability condition, and the time since the ADAS SBW control was turned off, such that: Ksteer=αKsteerNorm+(1−α)KsteerADAS; where α = f(vehicle speed, lane stability, time since ADAS intervention) ∈ [0, 1]; and δrwacmndnorm=δhwaKsteer, K steerADAS the ADAS steering ratio is defined as KsteerADAS=δhwaADASδrwacmndADAS is; K steerNorm the manual steering ratio is defined as KsteerNorm=δhwaδrwacmndnorm is; δ hwaADASis a handwheel angle commanded by ADAS, and δrwacmndADAS is an ADAS commanded wheel angle; δ hwa a handwheel angle commanded by the driver; δrwacmndnorm a wheel angle commanded by the driver.

[0019] According to yet another aspect of the present disclosure, the method includes automatically and dynamically adjusting handwheel stiffness by adjusting torque outputs of the steering emulator based on static and dynamic information about the vehicle and information about the vehicle's surroundings obtained by the one or more sensors, from the rack and pinion motor, and from the steering emulator, and based on the vehicle operator's attention levels, the vehicle operator's past preferences, the capability and availability of the ADAS SBW control trajectory tracking, including obstacles identified by the one or more sensors.The method further includes identifying obstacles and both preventing the vehicle operator from causing a collision of the vehicle with the obstacles and assisting the vehicle operator in navigating dynamic driving scenarios by dynamically adjusting a steering ratio gain and changing an effectiveness of operator inputs to the handwheel.

[0020] According to yet another aspect of the present disclosure, the method includes activating a collaborative steering feedback system and receiving vehicle state information, control commands, and steering characteristics; and generating a handwheel torque overlay command. The handwheel torque overlay command is sent to the steering emulator and overlaid with torque inputs from the vehicle operator, and a coordinated desired steering angle command is sent to the rack and pinion motor. The handwheel torque overlay is defined as follows: Δτdf=f(τd,pd,ps,x˙,δ˙,δref,m)=kv δ˙×[αd(x˙,δ˙,δref)pd+αs(x˙,δ˙)ps] where τ d a handwheel torque applied by the driver; p d is a driver preference; p s is a trigger for adjusting the steering feel; δ is a measured wheel angle; e is a trajectory following error; x is a vehicle state; m is a steering performance mode; δref is a desired steering angle command; δ c is a wheel angle command; and k v is a variable gain.

[0021] According to yet another aspect of the present disclosure, a system for collaborative steering in steer-by-wire (SBW)-equipped vehicles includes a vehicle and one or more sensors mounted on the vehicle that collect static and dynamic information about the vehicle and an environment surrounding the vehicle. The system further includes a rack and pinion motor disposed on a steering rack of the vehicle, the rack and pinion motor selectively adjusting an angular position of one or more steerable road wheels of the vehicle, and a steering emulator connected to a handwheel of the vehicle that selectively generates torque and adjusts an angular position of the handwheel, the steering emulator and the rack and pinion motor being in electronic communication with each other. The system further includes a controller having a processor, memory, and one or more input / output (I / O) ports.The I / O ports communicate with the one or more sensors, the rack and pinion motor, and the steering emulator. The processor executes programmatic control logic stored in memory, wherein the programmatic control logic comprises a collaborative steering system application (CSSA). The CSSA includes at least first, second, third, fourth, fifth, sixth, and seventh control logic.The first control logic receives static and dynamic information about the vehicle and the vehicle's surroundings from one or more sensors and from the steering emulator and the rack and pinion motor, including: a vehicle speed, a presence or absence of a trailer attached to the vehicle, a current road wheel angle, a current handwheel angle, and receives information about the vehicle's surroundings, including: a topology of a road section near the vehicle, a road type, a lane quality, a look-ahead curvature, current weather conditions, a field of view and a view distance of the one or more sensors, an object detection confidence, a lateral distance to surrounding vehicles, a magnitude of a lateral threat, a presence of an intersection, and a potential evasive steering maneuver.In response to the static and dynamic information, the second control logic generates one or more rack torque commands and rack angle commands for the rack motor and generates one or more emulator torque commands and emulator angle commands for the steering emulator. The second control logic determines a desired angle for the steerable road wheels and communicates the rack torque and / or rack angle command to the rack motor. Upon receiving the rack torque and / or rack angle command, the rack motor generates a torque output that changes an angle of the steerable road wheels; and determines a desired handwheel angle based in part on the angle of the steerable road wheels and a steering ratio at a current time step. The second control logic also communicates the emulator torque and / or emulator angle command to the steering emulator.Upon receiving the emulator torque and / or emulator angle command, the steering emulator generates a torque output that changes the angle of the handwheel. The third control logic determines a steering ratio between the angular movement of the steerable road wheels and the angular movement of the handwheel. The steering ratio is dynamically adjustable from at least one ADAS steering ratio to a manual steering ratio that differs from the ADAS steering ratio, and the steering ratio is dynamically adjusted in response to static and dynamic information about the vehicle and its surroundings.The fourth control logic selectively and automatically switches the vehicle steering control between the automated driver assistance system SBW control (ADAS SBW control) and the manual steering control based on the static and dynamic information about the vehicle and the vehicle's surroundings, based on a currently active ADAS function, and based on a current manual override or hands-free operating state of the handwheel. The fifth control logic smooths transitions between the ADAS SBW control and the manual steering control by maintaining feedback to the handwheel during assisted driving and controlling a timing and transition rate with a transition factor α. The transition factor α depends on the vehicle speed, the lane stability condition, and the time since the ADAS SBW control was turned off, such that: . Ksteer=αKsteerNorm+(1−α)KsteerADAS; where α = f(vehicle speed, lane stability, time since ADAS intervention) ∈ [0, 1]; and δrwacmndnorm=δhwaKsteer, K steerADAS the ADAS steering ratio is defined as KsteerADAS=δhwaADASδrwacmndADAS is; K steerNorm the manual steering ratio is defined as KsteerNorm=δhwaδrwacmndnorm is; δ hwaADAS is a handwheel angle commanded by ADAS, and δrwacmndADAS is an ADAS commanded wheel angle; δ hwa a handwheel angle commanded by the driver; δrwacmndnorm a road wheel angle commanded by the vehicle operator. The sixth control logic automatically and dynamically adjusts a handwheel stiffness by changing the emulator torque and / or emulator angle command in response to data from the one or more sensors and from the steering emulator and the rack and pinion motor, and in response to vehicle operator attention levels, previous vehicle operator preferences, capability and availability of the ADAS SBW control trajectory tracking, incorporating obstacles identified by the one or more sensors; automatically identifies obstacles and prevents the vehicle operator from causing a collision of the vehicle with the obstacles, and assists the vehicle operator in navigating dynamic driving scenarios by dynamically adjusting a steering ratio gain and changing an effectiveness of vehicle operator inputs to the handwheel.The seventh control logic coordinates a vehicle operator feedback control circuit with a trajectory tracking control circuit for ADAS, including collaborative steering feedback control logic that receives vehicle state information, steering commands, and steering characteristics and generates a handwheel torque overlay command. The handwheel torque overlay command is sent to the steering emulator and overlaid with torque inputs from the vehicle operator, and a coordinated desired steering angle command is sent to the rack and pinion motor. The handwheel torque overlay is defined as follows: Δτdf=f(τd,pd,ps,x˙,δ˙,δref,m)=kv δ˙×[αd(x˙,δ˙,δref)pd+αs(x˙,δ˙)ps] where τ d a handwheel torque applied by the driver; p d is a driver preference; p sis a trigger for adjusting the steering feel; δ is a measured wheel angle; e is a trajectory following error; x is a vehicle state; m is a steering performance mode; δ ref is a desired steering angle command; δ c is a wheel angle command; and k v is a variable gain. The seventh control logic further causes the rack motor and steering emulator to operate according to a kinematic model of a mechanical connection between the rack, handwheel, and steerable road wheels, while providing variable control gains that adjust road wheel response and driver steering feel based on the driving scenario and currently enabled driving functions.

[0022] According to yet another aspect of the present disclosure, the manual or hands-free operating state of the handwheel is determined by a touch sensor that detects the presence and / or absence of a vehicle operator's hands on the handwheel. If it is determined that the vehicle is operating in a hands-free operating state, the system selectively activates a function escalation state that prompts the vehicle operator to assume control of the steering.

[0023] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way; they show: Fig. 1 is a schematic diagram of a system for collaborative steering in steer-by-wire (SBW) systems for automated driving in vehicles according to an exemplary embodiment; Fig. 2 a flowchart illustrating an architecture for the SBW control of an advanced driver assistance system (ADAS SBW control) within the system for collaborative steering in steer-by-wire systems (SBW systems) for automated driving in vehicles of Fig. 1 according to an exemplary embodiment; Fig. 3 is a flowchart illustrating the logical flow of a collaborative steering system application (CSSA) of the system for collaborative steering in steer-by-wire (SBW) systems for automated driving in vehicles of Fig. 1 according to an exemplary embodiment; Fig. 4 is a flowchart illustrating the logical flow of a transition between ADAS SBW control and manual steering control using the CSSA within the system for collaborative steering in steer-by-wire (SBW) systems for automated driving in vehicles of Fig. 1, Fig. 2 and Fig. 3 according to an exemplary embodiment; Fig. 5 is a flowchart illustrating a process for selective handwheel stiffness adjustment of the CSSA within the collaborative steering system in steer-by-wire (SBW) systems for automated driving in vehicles from Fig. 1, Fig. 2, Fig. 3 and Fig. 4 according to an exemplary embodiment; Fig. 6 is a flowchart illustrating the implementation of collaborative steering in the steer-by-wire system for automated driving in vehicles of Fig. 1 and includes a collaborative steering trajectory tracking control circuit (collaborative steering TTCL) and a collaborative steering driver feedback control circuit (collaborative steering OFCL) according to an exemplary embodiment; and Fig. 7 a pair of graphical representations of an exemplary handover between ADAS-SBW control of the handwheel angle without influencing the impeller angle using collaborative steering in the steer-by-wire system for automated driving in vehicles of Fig. 1 according to an exemplary embodiment. DETAILED DESCRIPTION

[0025] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses.

[0026] With reference to Fig. 1, a system 10 for collaborative steering in steer-by-wire (SBW) systems for automated driving in vehicles 12 is shown in schematic form. The system 10 operates with the vehicle 12. Although the vehicle 12 shown is a car, it should be noted that the vehicle 12 may be a van, bus, semi-trailer truck, tractor-trailer, SUV, truck, bicycle, e-bike, tricycle, motorcycle, airplane, helicopter, amphibious vehicle, or any other such vehicle without departing from the scope or intent of the present disclosure. In the Fig. 1, the vehicle 12 is equipped with a drivetrain 14 that can transmit drive power to the road wheels 16 of the vehicle and to the tires 18 attached to the road wheels 16. The drivetrain 14 may include a number of components such as internal combustion engines (ICEs) 20 and / or electric motors 22, and transmissions 24 that can transmit torque from the ICEs 20 and / or electric motors 22 to the road wheels 16. In one example, the vehicle 12 may include an ICE 20 acting on a rear axle 26 of the vehicle 12 and one or more electric motors 22 acting on a front axle 28 of the vehicle 12.In additional examples, the vehicle 12 may utilize one or more ICEs 20 and / or one or more electric motors 22 arranged in additional configurations and providing torque to either a front or rear axle 28, 26, or even to individual road wheels 16 of the vehicle 12, without departing from the scope or intent of the present disclosure.

[0027] In several aspects, the powertrain 14 includes one or more in-plane actuators 30. The in-plane actuators 30 may include all-wheel drive (AWD) systems, including electronically controlled or electric AWD (eAWD) systems 32, and limited-slip differentials (LSD) 34, including electronically controlled or electric LSD (eLSD) systems 36. In-plane actuators 30 may, within a predetermined capacity, generate or modify force generation in the X and / or Y directions at a contact patch 38 between the tire 18 and the road surface. An eAWD system 32 may transfer torque from a front to a rear of the vehicle 12 and / or from side to side of the vehicle. Likewise, an eLSD 36 may transfer torque from side to side of the vehicle.In some examples, the eAWD 32 and / or the eLSD 36 may directly change or control the torque output from the engine 20 and / or the electric motors 22, and / or the eAWD 32 and the eLSD 36 may interact with a braking system 40 to adjust an amount of torque delivered to each of the tires 18 of the vehicle 12. Additional in-plane systems 30 may include active steering systems, electronic power steering (EPS) systems, and / or steer-by-wire (SBW) systems 42 on one or both of the front and rear axles 28, 26. Active, EPS, and / or SBW systems 42 may actively adjust an angle of the road wheels 16 relative to the longitudinal axis X of the vehicle 12.

[0028] According to further examples, the vehicle 12 may include a means for changing a normal force on each of the tires 18 of the vehicle 12 via one or more out-of-plane actuators 44. The out-of-plane actuators 44 of the vehicle 12 may include any of a wide variety of actuators 44 that can control the vertical movement of the vehicle 12. In several aspects, the out-of-plane actuators 44 may include active aerodynamic actuators 46, active suspension actuators 48, or the like. Active aerodynamic actuators 46 may actively or passively change an aerodynamic profile of the vehicle via one or more active aerodynamic elements 49 such as wings, spoilers, fans or other suction devices, actively controlled venturis, splitters, or the like. Active suspension actuators 48 adjust suspension travel, spring rates, and damping characteristics.According to some examples, the active suspension actuators 48 may include magnetorheological dampers, pneumatic dampers or springs, or other such electrically, hydraulically, or pneumatically adjusted dampers or springs without departing from the scope or purpose of the present disclosure.

[0029] The terms "forward," "rearward," "inward," "inside," "outward," "outside," "over," and "under" are terms used with reference to the orientation of the vehicle 12 as shown in the drawings of the present application. Thus, "forward" refers to a direction toward a front of a vehicle 12, "rearward" refers to a direction toward a rear of a vehicle 12. "Left" refers to a direction toward a left side of the vehicle 12 relative to the front of the vehicle 12. Similarly, "right" refers to a direction toward a right side of the vehicle 12 relative to the front of the vehicle 12."Inside" and "inward" refer to a direction toward the interior of a vehicle 12, and "outside" and "outward" refer to a direction toward the exterior of a vehicle 12. "Below" refers to a direction toward the underside of the vehicle 12, and "over" refers to a direction toward a top of the vehicle 12. Further, the terms "top," "overhang," "bottom," "side," and "over" are terms used relative to the orientation of the actuators and the vehicle 12, which is more generally illustrated in the drawings of the present application. Although the orientation of the actuators 30, 44 or the vehicle 12 may change with respect to a particular use, these terms are nevertheless intended to be relative to the orientation of the components of the system 10 and the components of the vehicle 12 shown in the drawings.

[0030] The system 10 further includes one or more controllers 50. The controllers 50 are non-generalized electronic control devices having a pre-programmed digital computer or processor 52, a non-transitory computer-readable medium or memory 54 for storing data such as control logic, software applications, instructions, computer code, data, lookup tables, etc., and input / output (I / O) ports 56. The computer-readable medium or memory 54 includes any type of medium accessible by a computer, such as read-only memory (ROM), random access memory (RAM), a hard disk drive, solid-state storage, a compact disc (CD), a digital video disc (DVD), or any other type of memory 54. Non-transitory computer-readable memory 54 excludes wired, wireless, optical, or other communication links that carry transient electrical or other signals.Non-transitory computer-readable memory 54 includes media on which data can be permanently stored and media on which data can be stored and later overwritten, such as a rewritable optical disk or an erasable storage device. Computer code includes any type of program code, including source code, object code, and executable code. The processor 52 is configured to execute the code or instructions. The vehicle 12 may include controllers 50, including a dedicated Wi-Fi controller, an engine control module, a transmission control module, a body control module, a suspension control module, a brake control module, an infotainment control module, or the like. The I / O ports 56 may be configured to communicate via wired communication, wirelessly via Wi-Fi protocols conforming to IEEE 802.11a, or wirelessly via Wi-Fi protocols conforming to IEEE 802.11b.11x, cellular connections, satellite connections, or the like, without departing from the scope or intent of this disclosure.

[0031] The on-board controller 50 further includes one or more applications 68. An application 68 is a software program configured to perform a particular function or set of functions. The application 68 may include one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or a portion thereof adapted for implementation in suitable computer-readable program code. The applications 68 may be stored in the memory 54 or in an additional or separate memory 54. In several aspects, the applications 68 may manage powertrain system functions, suspension system functions, braking system functions, aerodynamic system functions, steering system functions, and / or body control system functions in an example vehicle 12.

[0032] The applications 68, which manage powertrain system functions, suspension system functions, braking system functions, aerodynamic system functions, steering system functions, and body control system functions in the vehicle 12, receive static and / or dynamic vehicle condition information or sensor data from a collection of sensors 70 located on the vehicle 12. The sensors 70 may include a wide variety of sensors 70, including inertial measurement units (IMUs) 72, suspension control units such as semi-active damping suspension (SADS) 74, global positioning system (GPS) sensors 76, wheel speed sensors 78, throttle position sensors 80, accelerator pedal position sensors 82, brake pedal position sensors 84, steering position sensors 86, tire pressure monitoring sensors 88, aerodynamic element position sensors 90, and the like. The IMUs 72 measure motion, acceleration and the like in multiple degrees of freedom.According to one specific example, the IMUs 72 may measure position, motion, acceleration, and the like in three or more degrees of freedom. Likewise, the sensors of the SADS 74 may be IMUs 72 that can measure in three or more degrees of freedom. According to some more specific examples, the SADS 74 may be suspension hub accelerometers or the like. The sensor data may therefore include, but is not limited to, speed data of the road wheel 16, data related to the SADS 74 and IMU 72, including attitude, acceleration, and the like.

[0033] The system 10 further includes a steering wheel or handwheel 92 that communicates with a rack 94 that can change an angular position of the steerable road wheels 16 of the vehicle 12. The steering wheel or handwheel 92 is a human-machine interface (HMI) device that can be grasped and operated by a human operator of the vehicle 12. According to one embodiment, the steering wheel or handwheel 92 is wirelessly connected to the rack 94. More specifically, the steering wheel or handwheel 92 is mechanically and / or electronically connected to a steering emulator 96. The steering emulator 96 wirelessly transmits data from the steering emulator 96 to the rack 94, where a rack motor 98 mechanically, pneumatically, hydraulically, and / or electronically changes a position of the rack 94 and thus the angular position of the steerable road wheels 16.The steering emulator 96 uses kinematics to model a mechanical connection between the rack 94, the handwheel 92 and the steerable wheels 16.

[0034] In several aspects, the sensor data from the sensors 70 is received via the I / O ports 56 by a collaborative steering system application (CSSA 200). The CSSA 200 uses the sensor data about the vehicle 12 to determine what positions the in-plane actuators 30 and out-of-plane actuators 44 should have to achieve a particular state of the vehicle 12 and provide resilient, redundant, and accurate control of the movements of the vehicle 12.

[0035] The CSSA 200 receives sensor data from the one or more sensors 70 and in-plane and out-of-plane actuators 30, 44 and transmits the sensor data as input signals to a series of subroutines of the CSSA 200 that process the sensor data to perform functions of active, EPS, and / or SBW systems 42. In several aspects, the CSSA 200 maintains feedback from the steering or handwheel 92 to the operators of the vehicle 12 during assisted driving with automated driver assistance system (ADAS)-specific steering ratios 100 and, upon cessation of control of the SBW system 42 of the ADAS 100, smoothly transitions the steering ratio between the one or more ADAS 100-specific steering ratios and a normal steering ratio according to transition factor α.

[0036] With reference to Fig. 2 and with continued reference to Fig. Figure 1 illustrates the architecture for the SBW control of the ADAS 100 in more detail in the form of a flowchart. The SBW control of the ADAS 100 begins with the receipt of a driver torque τ driver on the handwheel 92. A change in the position of the handwheel 92 occurs at block 102 and is called the handwheel angle δ HW At block 104, a rack motor control subroutine of the CSSA 200 receives either a torque or angle command τ HW / δ HW,cmnd as well as a feedforward control gain K ff . The torque or angle command τ HW / δ HW,cmnd resembles the effect of a driver command 12 on a conventional steering system in a vehicle 12 without SBW. The feedforward control gain K ff adjusts a reaction rate of the angles of the steerable wheels 16 relative to the input of the handwheel 92. If K ff= 0, the handwheel 92 is accordingly freely movable and has no influence on the angles of the steerable wheels 16. The rack motor control subroutine in block 104 generates a torque τ rack for the rack 94, which in block 106 serves as input for the dynamics of the impeller 16 and in block 108 as input for an angular ratio K RW2HW between impeller 16 and handwheel 92. From block 106 onwards, the rack and pinion motor 98 generates an impeller angle δ RW According to several aspects, the angle ratio K RW2HW between the wheel 16 and the handwheel 92 and enables the driver of the vehicle 12 and / or the ADAS 100 to control the steering ratio at any handwheel angle δ hwa to steer more or less harshly or aggressively or vice versa. The angle ratio K RW2HW between impeller 16 and handwheel 92 is transmitted as input and at 110 from the handwheel angle δ HWbefore being used as input for controlling the rack motor 98 at block 104. In addition to outputting the torque τ rack of the rack 94 to the dynamics of the impeller 16 at block 106, the control 104 of the rack motor 98 sends the torque τ rack the rack 94 at block 112 to a feedback motor controller or motor controller of the steering emulator 96. The controller of the steering emulator 96 uses the torque τ rack the rack 94 in combination with a feedback control gain K fb and a torque or angle command τ RW / δ RW,cmnd to the motor controller of the steering emulator 96 as inputs to then generate a feedback torque τ fb which is received by the steering emulator 96 and at 114 with the torque τ driverof the driver of the vehicle 12 is summed to adjust or change the position of the handwheel 92 at block 102. The feedback control gain K fb defines a feedback response to a torque applied by the rack motor 98 to the rack 94, while the torque or angle command τ RW / δ RW,cmnd to the motor controller of the steering emulator 96 are analogous to the mechanical feedback from the rack 94 in a conventional non-SBW steering system.

[0037] With reference to Fig. 3 and with further reference to Fig. 1 shows a schematic representation of the functions of the CSSA 200 in more detail in the form of a flow chart. The CSSA 200 begins where a driver torque τ driver is exerted via the handwheel 92. The driver torque τ driver is an input 210 into the handwheel 92, which results in a handwheel angle δ hwawhich is used as input for both the steering emulator 96 and the control of the SBW system 42 of the ADAS 100. Partially based on the handwheel angle δ hwa the steering emulator 96 performs a position control of the rack 94, which is known as δ rwa_cmndnorm = f(δ hwa ), where S rwa_cmnd the angle command of the steerable wheels 16 to the rack motor 98 as a function of the handwheel angle δ hwa The steering emulator 96 also provides feedback to the handwheel 92 through a torque emulation of the handwheel 92, which is defined by τ emulator = f(δ rwa , δ hwaADAS ), where τ emulator is defined as the torque feedback of the handwheel 92 from the emulator 96 to the driver of the vehicle 12. When fully or partially controlled by the ADAS 100, the position control of the rack 94 of the ADAS 100 is a function of both a reference steering angle δ refas well as the handwheel angle δ hwa defined. δ ref is a position of the steering rack 94 determined by the ADAS 100 to follow a path of the vehicle 12 planned by the ADAS 100. According to one embodiment, the position control of the steering rack 94 during full or partial operation of the ADAS 100 may be defined as follows: δ rwa_cmndADAS = f(δ ref , δ hwa ), where δ rwa_cmndADAS the angle command of the steerable wheel 16 to the rack motor 98 during control of the ADAS 100.

[0038] The rack motor 98 receives angular position commands of the steerable road wheels 16 from both the ADAS 100 and the steering emulator 96 and generates a position of the rack 94 based thereon. The position δ rwa the rack 94 is a function of the angular position commands from both the ADAS 100 and the steering emulator 96 as well as predefined data such as a system model G rackof the rack motor 98, the alignment and / or the alignment torque τ tire from the tires 18 of the steerable wheels 16 and the like. Accordingly, the position δ rwa the rack can be defined as follows: δrwa=f(Grack,δrwacmndADAS,δrwacmndnorm,τtire). The rack motor 98 also sends position data back to the ADAS 100 and the emulator 96 so that the ADAS 100 can actively, automatically, adaptively, and continuously update path positioning commands to the rack motor 98 in future time steps and so that the driver of the vehicle 12 can, by means of the handwheel 92 and the emulator torque τ emulator , which is exerted on the handwheel 92 via the steering emulator 96, is informed as feedback to the driver of the vehicle 12 about the positions of the steerable wheels 16.

[0039] According to several embodiments, the CSSA 200 maintains the ADAS 100 specific steering ratio as a function of the ADAS commanded handwheel steering angle δ hwaADAS and the angle of the steerable wheels commanded by the ADAS 16 δ rwa_cmndADAS according to: KsteerADAS=δhwaADASδrwa_cmndADAS Similarly, after the SBW system 42 of the ADAS 100 has ceased to control the steering ratio, the steering ratio is changed to be a function of the handwheel angle δ commanded by the driver of the vehicle 12. hwa and the angle of the steerable wheels δ commanded by the driver of the vehicle 12 rwa_cmndnorm according to KsteerNorm=δhwaδrwa_cmndnorm The transition between the steering ratio K steerADAS of the ADAS 100 and the normal steering ratio K steerNormis a function of the transition factor α, which is a function of the speed of the vehicle 12, the stability of the vehicle 12 within a lane or on a road surface, a period of time since an intervention by the ADAS 100, and the like, and can be represented as follows: α = f(vehicle speed, lane stability, time since ADAS intervention) ∈ [0, 1];. Likewise, when the ADAS 100 terminates control: K steer = αK steerNorm + (1-α)K steerADAS . According to several aspects, the angle of the steerable road wheels δ commanded by the driver of the vehicle 12 rwa_cmndnorm when the ADAS 100 is not in operation, be defined as follows: δ rwa_cmndnorm = δ hwa / K steer .

[0040] With reference to Fig. 4 and with further reference to Fig. 1-3, the transition between ADAS 100-assisted and manual driving of the vehicle 12 using the CSSA 200 is illustrated in more detail. In several aspects, the transition is managed with a transition state machine 202. The transition state machine 202 is a subroutine of the CSSA 200 that uses a touch sensor within the handwheel 92 of the vehicle 12 to determine when the operator of the vehicle 12 manually operates the handwheel 92. The touch sensor may be any of a variety of touch-sensitive devices, including, but not limited to, capacitive touch sensors, resistive touch sensors, optical imaging touch sensors, surface acoustic wave sensors, infrared sensors, piezoelectric sensors, humidity sensors, and / or force sensors, without departing from the scope or intent of the present disclosure.The touch sensor provides data to the transition state machine 202 regarding the current manual or hands-free operating state of the handwheel 92. In several aspects, the manual or hands-free operating state of the handwheel 92 is associated with individual and varying steering ratios, which may be determined in part from the preferences of the operator of the vehicle 12 and the like. The transition state machine 202 determines how long a transition between automated or semi-automatic steering and manual steering should last. In several aspects, the manual state is defined by the touch sensor-based detection of the hands of the operator of the vehicle 12 on the handwheel 92. A function escalation state is used to request the operator of the vehicle 12 to assume control of the steering.A function escalation may be issued in certain predefined and / or urgent situations to request the operator of the vehicle 12 to assume control of the steering of the vehicle 12. However, it should be understood that the operator of the vehicle 12 has the ability to assume control at any time. When the operator of the vehicle 12's hands are detected on the handwheel 92 and a transition between automatic and manual steering is initiated, the system 10 uses the transition preference information of the operator of the vehicle 12 to enable the operator of the vehicle 12 to assume steering in a smooth, comfortable, and easily controllable manner. According to some embodiments, the transition between automatic and manual control of the steering may be implemented as a linear change, exponential change, or the like between the steering ratio K. steerADAS of the ADAS 100 and the normal steering ratio K steerNormdefined or calibrated. It should be noted that the transition is controlled to be predictable, smooth, comfortable, and easily controllable so that the comfort and confidence of the operator of the vehicle 12 is maintained. According to further embodiments, the information regarding the transition preferences of the operator of the vehicle 12 may be learned over time from the behavior of the operator of the vehicle 12 and / or defined as any of a series of presets accessible via an instrument cluster, central control stack, or other such HMI of the vehicle 12 or within an application 68 within a mobile device of an operator of the vehicle 12 that is in communication with the controllers 50 of the vehicle 12.Likewise, in the hands-free state, the transition state machine 202 determines, via data from the touch sensors or the like, that the operator of the vehicle 12 is not manually operating the handwheel 92 and that the functional state is enabled in an autonomous or semi-autonomous hands-free mode, and utilizes the transition preferences of the operator of the vehicle 12 to manage the transition between manual steering and autonomous or semi-autonomous control of the steering rack 94 of the vehicle 12.

[0041] If the transition state machine 202 determines that a transition between manual and automatic control of the steering is required or in progress, the transition state machine 202 sets a transition flag 204 for the transition of control of the handwheel 92 as "true" at block 206. The transition of control of the handwheel 92 begins when the provided transition flag 204 is true. For a calibratable time "t," the transition of the handwheel 92 may be δhwaADAStarget(t) be defined, whereby δhwaADAStarget(t) linearly, exponentially or the like with time. The control of the handwheel 92 is then carried out via the steering emulator 96 both as a torque emulation τemulator=f(δrwa,δhwaADAStarget(t)) as well as an angle emulation of the handwheel 92 according to the respective manual or automated steering processes in which the vehicle 12 is currently engaged. In several aspects, the steering ratio selection in block 208 may be a calibration defined by the operator of the vehicle 12, a calibration learned from the driving history of the operator of the vehicle 12, or one of any number of presets. The steering ratios include at least one hands-free steering ratio calibration K steerADAS_H_Off , where δhwaADAS_H_Offδrwa_cmndADAS , which is applicable when functions of the ADAS 100 are activated and when the driver of the vehicle 12 does not manually operate the handwheel 92, and a manual steering ratio calibration K steerADAS_H_On , where δhwaADAS_H_Onδrwa_cmndADAS, when functions of the ADAS 100 are activated and the driver of the vehicle 12 manually operates the handwheel 92. The manual operation and / or hands-free steering ratio calibration K steerADAS_H_Off , K steerADAS_H_On is used to determine the position of the handwheel 92 based on target angles δ hwaADAS_H_On / δ hwaADAS_H_Off of the handwheel 92 and the control transition of the handwheel 92 in block 206.

[0042] With reference to Fig. 5 and with further reference to Fig. 1-4, the control of the handwheel 92 of the CSSA 200 includes a stiffness adjustment of the handwheel 92. The system 10 and the CSSA 200 manage stiffness adjustment based on the situation. That is, a natural-feeling stiffness of the handwheel 92 is provided so that in situations where the vehicle 12 is moving at significant speeds, such as highway speeds, the CSSA 200 increases the steering stiffness or firmness so that significant or sudden movements of the handwheel 92 are less likely to be unintentional inputs 210 from the operator of the vehicle 12. Accordingly, with tight and / or firm steering at high speeds, the operator of the vehicle 12 is more likely to intentionally cause the handwheel 92 to change position in response to the presence of traffic, curves in a current section of road, or the like.In contrast, the CSSA 200 and system 10 reduce steering resistance, stiffness, or firmness when sudden or significant inputs 210 from the operator of the vehicle 12 are received to the handwheel 92. That is, because traffic volume is light and the vehicle 12 is moving at relatively low speeds, such as parking lot speeds, changes in the angular position of the handwheel 92 are less likely to cause an unintended response from the vehicle 12, which could lead to collisions or erratic or uncontrollable movements of the vehicle 12. To ensure the predictable, controllable, comfortable, and natural-feeling stiffness of the handwheel 92 of the steering of the vehicle 12, the CSSA 200 utilizes various sensors 70 of the vehicle 12 to determine a current dynamic state 300 of the vehicle 12 as well as a state of the environment of the vehicle 12.

[0043] According to several aspects, the sensors 70 report road topology information 302, road type information R T , Track quality information Q L , Forward look curvature information C LAand the like, to determine the road classification in the vicinity of the vehicle 12. That is, the CSSA 200 uses the sensors 70 to determine whether the vehicle 12 is traveling on a multi-lane highway with wide lanes, at high speed, in a relatively straight path, and with a relatively large number of other vehicles in relatively close proximity and traveling in the same or similar directions on the same stretch of road. In contrast, the CSSA 200 may similarly use the sensors 70 to determine that the vehicle 12 is traveling on a small, single-lane rural road with many curves and few to no other vehicles in the immediate vicinity.It should be noted that the CSSA 200 may use the sensors 70 to accurately report road type, road shape, traffic, lane size and quality, and the like, of each road segment on which the vehicle 12 is traveling without departing from the scope or intent of the present disclosure.

[0044] The CSSA 200 also uses the sensors 70 to determine the status of the environment 304 surrounding the vehicle 12 on a particular road segment at the current time. According to several aspects, the sensors 70 may determine weather conditions, a visibility range of the sensors 70 of the vehicle 12, or the like. According to still further aspects, the sensors 70 report the presence or absence of surrounding objects 306 to the CSSA 200. Such object detection includes object detection confidence calculations C OL , C OR , a lateral distance D L , D Rto surrounding vehicles 12, a size of a lateral threat D T such as a size of another vehicle in the vicinity of the host vehicle 12, and the like. The sensors 70 also report information about the state of the vehicle 12 to the CSSA 200 in block 308. The information about the state of the vehicle 12 may include the speed V of the vehicle 12, whether or not a trailer is attached to the vehicle 12, a current direction of the vehicle 12, and the like.

[0045] The CSSA 200 also predicts possible maneuvers of the vehicle 12 in block 310. More specifically, the CSSA detects whether a bend is imminent based on the road curvature 312, recognizes intersections 314 on the road as the vehicle 12 approaches the intersections 314, and calculates potential evasive maneuvers 316 if and when sudden lane breaks or other actions of the vehicle 12 could impair the continued safe travel of the host vehicle 12. According to several aspects, evasive maneuvers 316 may be initiated when a significant speed difference of the host vehicle 12 relative to a stopped or very slow-moving vehicle is detected. That is, when the speed V of the host vehicle 12 is relatively high and the speed V trafficis very low or approaching 0, then the CSSA 200 may initiate an evasive maneuver 316 when the host vehicle 12 is within a predefined distance from the other stopped or slow-moving vehicles 12. In addition to performing or initiating the evasive maneuver 316, the CSSA 200 increases a steering gain ratio when such an evasive maneuver 316 is in progress to enable the vehicle 12 and the operator of the vehicle 12 to accurately and safely perform the evasive maneuver 316.

[0046] According to several aspects, the information about the current dynamic state 300 is used to adjust the stiffness of a handwheel 92 in block 318. The stiffness component Ws = f (R T , D Obj , C O , D T , ...) of the handwheel 92 is used to adjust the steering feel or feedback to the driver of the vehicle 12 via adjustments to the torque τ emulatorof the emulator 96. Accordingly, a torque τ exerted by the driver of the vehicle 12 drivertogether with maneuver prediction information 310 in the form of a dynamic steering ratio gain adjustment 320 is used as input 210 to the CSSA 200 within the controller 50 of the vehicle 12. The stiffness component Ws of the handwheel 92 can vary considerably and is understood to be dependent on availability, driving scenarios, environmental conditions, steering tracking capability, and the like. In further aspects, the stiffness of the handwheel 92 can vary depending on proximity to an intersection 314, when executing evasive maneuvers, and / or when turning the vehicle 12. Furthermore, the stiffness of the handwheel 92 can be automatically adjusted in response to the attention levels of the driver of the vehicle 12, previous preferences of the operator of the vehicle 12, the performance and availability of the trajectory tracking of the ADAS 100, environmental conditions, and the driving scenario.Stiffness levels may also be adjusted to inhibit or otherwise alter the effectiveness of the inputs 210 of the operator of the vehicle 12 to the handwheel 92 and thereby prevent the vehicle 12 from colliding with obstacles, other vehicles 12, side threats, guardrails, and the like when the sensors 70 detect such obstacles.

[0047] The controller 50 then executes the control logic of the CSSA 200, which uses a predictive controller 322 that provides a target path adjustment 324 and an adjustment for the weight of the operator of the vehicle 12. The vehicle 12 operator weight adjustment component 326 takes into account the tracking error e tr, the dynamic steering ratio, and the functional availability 328 to generate an output 320 for the handwheel stiffness adjustment 318. It should be noted that the predictive controller 322 of the CSSA 200 may be any of numerous controllers or control algorithm types, such as deep learning, model predictive control, classical control algorithms, or the like, without departing from the scope or intent of the present disclosure.

[0048] With reference Fig. 6 and with further reference to Fig. 1-5, the implementation of collaborative steering in the steer-by-wire system 10 is shown in flowchart form, including a collaborative steering trajectory tracking control loop (collaborative steering TTCL) and a collaborative steering feedback control loop (collaborative steering OFCL) for the operator of the vehicle 12. Both the TTCL 400 and the OFCL 402 utilize the input 210 of the handwheel 92 of the operator of the vehicle 12 to assist in both determining a steering feel or stiffness of the handwheel 92 generated by the steering emulator 96 and maintaining trajectory tracking of the vehicle 12 throughout full or partial operation of the ADAS 100 using an SBW controller 406. In several aspects, the input 210 of the operator of the vehicle 12 to the handwheel 92 may include a torque input or a torque input change of the handwheel 92 by the operator of the vehicle 12.The torque change Δτ. d of the OFCL 402 handwheel 92 is a function of a multitude of variables, including, without limitation, a steering preference p d of the driver of the vehicle 12, a trigger for adjusting the steering feel p s , measured angles δ of the road wheels 16, a path following error e, state information x of the vehicle 12 and a steering performance mode m as well as a target steering angle command δ ref The steering preference p d of the driver of the vehicle 12, the trigger for adjusting the steering feel p s, measured angles δ of the road wheels 16, and a path following error e are all generated at least in part by a computing platform of the ADAS 100 (ACP), which may be a physically or electronically distinct and separate controller 50, or a logic subroutine stored in the memory 54 of a single controller 50 of the vehicle 12 and executed by its processor 52, without departing from the scope or intent of the present disclosure. The state information x of the vehicle 12 is generated by the various sensors 70 and actuators 30, 44 of the vehicle 12, while the steering performance mode m is generated or selected by the operator of the vehicle 12 via the (EPS) systems and / or steer-by-wire (SBW) steering systems 42. Thus, the torque overlay Δτ df of the handwheel 92 of the driver of the vehicle 12 can be expressed as follows: Δτdf=f(τd,pd,ps,x˙,δ˙,δref,m)=kvδ˙×[αd(x˙,δ˙,δref)pd+αs(x˙,δ˙)ps], where k v = torque gain response to impeller angle change; α d = Amplification factor for the steering feedback preference of the driver of the vehicle 12, which is a function of (ẋ, δ̇, δ ref ) and α s = Gain factor for steering feel adaptation, which is a function of (ẋ, δ̇). The above Δτ df -equation can be viewed as having the following structure: Feedback of the angle of the road wheels 16 x [driver preference gain of the vehicle 12 + steering feel adjustment gain], so that]. The torque superposition Δτ df -Feedback to the driver of the vehicle 12 thus consists of a simulated kinematic feedback from the change in angle of the road wheels 16, which is modified by the preference of the driver of the vehicle 12 and the steering feel adjustment.

[0049] The TTCL 400 uses the torque change Δτ d of the handwheel 92 as input to a trajectory tracking controller 404. The trajectory tracking controller 404 may be a separate hardware device similar in construction to the previously described controllers 50, and / or the trajectory tracking controller 404 may be control logic, a subroutine, or an application 68 stored in the memory 54 of the controller 50 and executable by its processor 52 without departing from the scope or intent of the present disclosure. The trajectory tracking controller 404 uses data from various sensors 70 and actuators 30, 44 of the vehicle 12 to both determine and follow a planned trajectory and to determine a relative position of the vehicle 12 compared to the planned trajectory. The trajectory tracking controller 404 generates an angular command δ cfor the road wheels 16 and sends it to an SBW controller 406. The SBW controller 406 may be a subroutine or application 68 within the controller 50 or, in some embodiments, within a separate SBW controller or application 68. The SBW controller 406 then commands the rack and pinion motor 98 to adjust the angle of the steerable road wheels 16 in response to the angle command δ cfor the road wheels 16. The rack and pinion motor 98 also sends a desired angle of the handwheel 92 to the steering emulator 96, and the steering emulator 96, acting in response to the desired angle of the handwheel 92, changes a position of the handwheel 92 so that the driver of the vehicle 12 understands a current direction and trajectory of the vehicle 12. It should be noted that the CSSA 200 causes the angle of the handwheel 92 and the angles of the steerable road wheels 16 to be maintained or changed in a manner consistent with the capabilities of the vehicle 12 and the preferences and comfort of the driver of the vehicle 12.

[0050] The OFCL 402 starts in a similar way by receiving the torque change Δτ dof the handwheel 92 of the operator of the vehicle 12 as input. The operator of the vehicle 12 can also apply a torque to the handwheel 92. In response to the torque applied by the operator of the vehicle 12, the handwheel 92 transmits the torque τ applied by the operator of the vehicle 12 d physically and / or electronically to the steering emulator 96 and the steering emulator 96 transmits the measurement of the torque τ exerted by the driver of the vehicle 12 d to the controller 50 of the CSSA 200. In response to the torque τ exerted by the driver of the vehicle 12 dand the outputs from the trajectory tracking controller 404, via the SBW controller 406 and the rack and pinion motor 98, the command angle signal of the handwheel 92 is modified to include feedback or amplification that informs the operator of the vehicle 12 of changes in road curvature, obstacle and / or vehicle avoidance maneuvers, and assists the operator of the vehicle 12 in consistently maintaining control of the vehicle 12 according to the capabilities of the vehicle 12 and the preferences and comfort of the operator of the vehicle 12.

[0051] With reference to Fig. 7 and with further reference to Fig. 1-6, an exemplary handover between the control of the angle of the handwheel 92 by the ADAS 100 without influencing the angle of the impellers 16 is shown in more detail. More specifically, Fig. Figure 7 shows two graphical representations, in which the first diagram 600 shows the angle of the handwheel 92 and the second diagram 650 shows the angle of the impellers 16. Both the first and second diagrams 600, 650 are scaled so that time in seconds is defined on the X-axis, while the wheel angle is shown on the Y-axis. As time progresses in the diagrams from left to right, it is clear that at time T = 50, a connection between the angle of the handwheel 92 and the angle of the impellers 16 is broken, since the curves cease to follow each other there. The decoupling of the feedforward gain K ff =0 causes the handwheel 92 and the wheels 16 to be freely and seamlessly angularly movable relative to each other. Fig.7, the handwheel 92 and the road wheels 16 may be appropriately decoupled due to a transition to highway driving where sudden changes in the position of the steerable wheels 16 are undesirable. Accordingly, as can be seen from approximately time T=80 and up to approximately time T=100, the angle of the steerable wheels 16 remains relatively constant even though the driver of the vehicle 12 has caused a significant change in the angle of the handwheel 92. The disturbance to the angle of the handwheel 92 from time T=80 to T=100 may, for example, be an unintended input 210 to the handwheel 92, which, under highway driving conditions when the handwheel 92 and the steerable wheels 16 are fully coupled and moving angularly together, causes the vehicle 12 to respond unpredictably.Thus, by preventing, at least in a situation-dependent manner, inadvertent inputs 210 to the handwheel 92 by the operator of the vehicle 12 from drastically changing the angular position of the road wheels 16, the comfort and confidence of the operator of the vehicle 12 are maintained. According to some examples, the operator of the vehicle 12 may also explicitly and intentionally work against the CSSA 200, which includes counteracting steering inputs commanded by the ADAS 100. In such situations, the CSSA 200 does not completely prevent the steering inputs 210 of the operator of the vehicle 12, but rather smooths the inputs 210 of the operator of the vehicle 12 to maintain the stability, comfort, and confidence of the operator of the vehicle 12.

[0052] A system 10 for collaborative steering in SBW-equipped vehicles 12 with autonomous driving capabilities of the present disclosure offers several advantages. These include the ability to provide a consistent, confidence-inspiring, and connected steering feel via the handwheel 92, as well as consistent dynamics of the vehicle 12, including acceleration, deceleration, lateral acceleration, and the like, via the idler wheel 16 and rack and pinion drive 98. The system 10 of the present disclosure further improves vehicle operator comfort, increases the sense of connectedness between the movements of the idler wheels 16 and the handwheel 92, and provides effective and smooth transitions between autonomous driving controlled by the ADAS 100 and manual steering movements, while maintaining or reducing the complexity of the system components 10, thereby providing redundancy.Furthermore, the system 10 of the present disclosure can be applied to new vehicles 12 as well as retrofitted into existing vehicles 12 with suitable hardware SBW steering systems 42, while maintaining or reducing the hardware complexity of the system 10. The system 10 of the present disclosure provides a novel architecture and methodology for automated and collaborative steering in SBW systems 42. The ADAS 100 calculates a set of commands including the angle of the road wheels 16 and a torque of the steering rack 94 required to achieve the angle of the road wheels 16 within a specified period of time. The ADAS 100 also generates a feedback command to the steering emulator 96 and a dynamic steering ratio command.The CSSA 200 enables dynamic steering ratios in ADAS 100 applications, collaborative steering between the driver of the vehicle 12 and the full control of the ADAS 100, as well as automatic, adaptive and continuous adjustment of the steering feel and provision of a situation-appropriate steering response, and enables smooth transitions between the control of the ADAS 100 and manual or exclusive control by the driver of the vehicle 12.

[0053] The description of the present disclosure is merely exemplary in nature, and variations that do not depart from the spirit of the present disclosure are intended to be included within the scope of the present disclosure. Such variations should not be regarded as a departure from the spirit and scope of the present disclosure.

Claims

[1] System for collaborative steering in vehicles equipped with steer-by-wire (SBW), comprising: a vehicle; one or more sensors mounted on the vehicle that collect static and dynamic information about the vehicle and an environment around the vehicle; a rack and pinion motor disposed on a rack of the vehicle, the rack and pinion motor selectively adjusting an angular position of one or more steerable road wheels of the vehicle; a steering emulator connected to a handwheel of the vehicle and selectively generating torque and adjusting an angular position of the handwheel, the steering emulator and the rack and pinion motor being in electronic communication with each other; a controller having a processor, a memory, and one or more input / output ports (I / O ports), wherein the I / O ports communicate with the one or more sensors and the rack motor and the steering emulator, the processor executes programmatic control logic stored in the memory, and the programmatic control logic comprises a collaborative steering system application (CSSA), the CSSA comprising: a first control logic that receives static and dynamic information about the vehicle and the environment around the vehicle from one or more sensors and from the steering emulator and the rack motor; a second control logic that, in response to the static and dynamic information, generates one or more of a rack torque command and a rack angle command for the rack motor and generates one or more of an emulator torque command and an emulator angle command for the steering emulator; a third control logic that determines a steering ratio between the angular movement of the steerable road wheels and the angular movement of the handwheel, the steering ratio being dynamically adjustable from at least one ADAS steering ratio to a manual steering ratio that is different from the ADAS steering ratio; a fourth control logic that selectively and automatically switches the vehicle steering control between the automated driver assistance system (ADAS SBW) control and the manual steering control; a fifth control logic that smooths transitions between the ADAS SBW control and the manual steering control; a sixth control logic that automatically and dynamically adjusts handwheel stiffness by changing the emulator torque command in response to data from one or more sensors and from the steering emulator and the rack motor; and a seventh control logic that coordinates a driver feedback control circuit with a trajectory tracking control circuit for ADAS and causes the rack motor and steering emulator to operate according to a kinematic model of a mechanical connection between the rack, the handwheel, and the steerable road wheels, while providing variable control gains that adjust road wheel response and driver steering feel based on the driving scenario and the currently activated driving functions. [2] The system of claim 1, wherein the first control logic further comprises: a control logic for obtaining static and dynamic information about the vehicle, including: a vehicle speed, a presence or absence of a trailer attached to the vehicle, a current idler wheel angle, a current handwheel angle; and control logic for obtaining information about the environment of the vehicle, including: a topology of a road segment near the vehicle, a road type, a lane quality, a look-ahead curvature, current weather conditions, a field of view and a view range of the one or more sensors, an object detection confidence, a lateral distance to surrounding vehicles, a magnitude of a lateral threat, a presence of an intersection, and a potential evasive steering maneuver. [3] The system of claim 1, wherein the second control logic further comprises: a control logic that determines a desired angle of steerable road wheels and transmits the rack torque and / or rack angle command to the rack motor, wherein the rack motor, upon receiving the rack torque and / or rack angle command, generates a torque output that changes an angle of the steerable road wheels; and control logic that determines a desired handwheel angle based in part on the angle of the steerable road wheels and a steering ratio at a current time step; and transmits the emulator torque and / or emulator angle command to the steering emulator, wherein the steering emulator, upon receiving the emulator torque and / or emulator angle command, generates a torque output that changes an angle of the handwheel. [4] System according to claim 1, wherein the third control logic dynamically adjusts the steering ratio in response to the static and dynamic information about the vehicle and the environment around the vehicle. [5] System according to claim 1, wherein the fourth control logic selectively and automatically switches the vehicle steering control between the SBW control of the automated driver assistance system (ADAS SBW control) and the manual steering control based on the static and dynamic information about the vehicle and the environment around the vehicle based on a currently active ADAS function and based on a current manual override or hands-free operating state of the handwheel. [6] System according to claim 5, wherein the manual or hands-free operating state of the handwheel is determined by a touch sensor that detects the presence and / or absence of a vehicle operator's hands on the handwheel, and wherein, when it is determined that the vehicle is operating in a hands-free operating state, the system selectively activates a function escalation state that prompts the vehicle operator to assume control of the steering. [7] System according to claim 1, wherein the fifth control logic smooths transitions between the ADAS SBW control and the manual steering control by maintaining feedback to the handwheel during assisted driving and controlling a timing and a transition rate with a transition factor α, the transition factor α depending on the vehicle speed, the lane stability condition and the time since the ADAS SBW control was switched off, such that: Ksteer=αKsteerNorm+(1−α)KsteerADAS; where α = f(vehicle speed, lane stability, time since ADAS intervention) ∈ [0, 1]; and δrwacmndnorm=δhwaKsteer, K steerADAS the ADAS steering ratio as KsteerADAS=δhwaADASδrwacmndADAS is defined; K steerNorm the manual steering ratio as KsteerNrom=δhwaδrwacmndnorm is defined; δ hwaADAS is a handwheel angle commanded by ADAS, and δrwacmndADAS is an ADAS commanded wheel angle; δ hwa is a handwheel angle commanded by the driver; δrwacmndnorm a wheel angle commanded by the driver. [8] The system of claim 1, wherein the sixth control logic further comprises: a control logic that automatically and dynamically adjusts a handwheel stiffness by adjusting the steering emulator torque outputs based on static and dynamic information about the vehicle and information about the vehicle's surroundings obtained within the first control logic, and based on the driver's attention levels, the driver's previous preferences, the capability and availability of the ADAS SBW control trajectory tracking, taking into account obstacles identified by the one or more sensors; and a control logic that identifies obstacles and prevents the driver from causing a collision of the vehicle with the obstacles, as well as assists the driver in navigating dynamic driving scenarios by dynamically adjusting a steering ratio gain and changing an effectiveness of driver inputs to the handwheel. [9] The system of claim 1, wherein the seventh control logic further comprises: a collaborative steering feedback control logic that receives vehicle state information, steering commands, and steering characteristics and generates a handwheel torque overlay command, wherein the handwheel torque overlay command is sent to the steering emulator and overlaid with torque inputs from the vehicle operator, and a coordinated desired steering angle command is sent to the rack motor, wherein the handwheel torque overlay is defined as follows: Δτdf=f(τd,pd,ps,x˙,δ˙,δref,m)=kvδ˙×[αd(x˙,δ˙,δref)pd+αs(x˙,δ˙)ps] where τ d a handwheel torque applied by the driver; p d is a driver preference; p s is a trigger for adjusting the steering feel; δ is a measured wheel angle; e is a trajectory following error; x is a vehicle state; m is a steering performance mode; δ rer is a desired steering angle command; δ c is a wheel angle command; and k v is a variable gain. [10] A method for collaborative steering in vehicles equipped with steer-by-wire (SBW), the method comprising: Collecting static and dynamic information about the vehicle and an environment around the vehicle using one or more sensors arranged on a vehicle with which the vehicle is equipped; selectively adjusting an angular position of one or more steerable road wheels of the vehicle with a rack and pinion motor arranged on a rack of the vehicle; selectively generating a torque and adjusting an angular position of a handwheel with a steering emulator connected to the handwheel of the vehicle, the steering emulator and the rack and pinion motor being in electronic communication with each other; Executing programmatic control logic comprising a collaborative steering system application (CSSA) stored in a memory of a controller of the vehicle, the controller having a processor, the memory, and one or more input / output (I / O) ports, the I / O ports communicating with the one or more sensors and the rack motor and the steering emulator, the CSSA comprising: Obtaining static and dynamic information about the vehicle and the environment around the vehicle from one or more sensors and from the steering emulator and the rack motor; Generating one or more of a rack torque command and a rack angle command for the rack motor in response to the static and dynamic information, and generating one or more of an emulator torque and / or an emulator angle command for the steering emulator; Determining a steering ratio between the angular movement of the steerable road wheels and the angular movement of the handwheel, wherein the steering ratio is dynamically adjustable from at least one ADAS steering ratio to a manual steering ratio different from the ADAS steering ratio; automatic selective switching of a vehicle steering control between the SBW control of the automated driver assistance system (ADAS SBW control) and the manual steering control; Smoothing transitions between ADAS SBW control and manual steering control; automatically and dynamically adjusting a handwheel stiffness by changing the emulator torque command in response to data from one or more sensors and from the steering emulator and the rack motor; and Coordinating a vehicle driver feedback control circuit with a trajectory tracking control circuit for ADAS and causing the rack motor and steering emulator to operate according to a kinematic model of a mechanical connection between the rack, handwheel, and steerable road wheels, while providing variable control gains that adjust road wheel response and vehicle driver steering feel based on the driving scenario and currently enabled driving functions.

Images