Method and apparatus for cooperative control of steer-by-wire system

Abstract

The present disclosure relates generally to a steer-by-wire system for a vehicle, and more particularly to a method and apparatus for cooperative control of a steer-by-wire system. An example steering-by-wire system (SBW steering system) for a vehicle includes machine-readable instructions and a control device to execute the machine-readable instructions to: determine a steering wheel angle of a steering wheel; causing the steering wheel actuator to apply a first feedback torque to the steering wheel based on the steering wheel angle and the target steering wheel angle; causing the steering wheel actuator to apply a second feedback torque to the steering wheel based on the steering wheel angle, the target steering wheel angle, and the user applied torque based on the user applied torque greater than the first feedback torque; and causing a road wheel actuator to steer the vehicle based on the steering wheel angle.

Description

[0001] Cross-reference to related applications This patent claims priority to German patent application number 102024133187.9, filed on November 13, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates generally to steer-by-wire systems for vehicles, and more specifically to methods and apparatus for coordinated control of steer-by-wire systems. Background Technology

[0003] Modern vehicle steering systems include advanced features such as lane-following, which allows for semi-autonomous or fully autonomous control of the vehicle's path. The driver can regain manual control of the vehicle by interacting with the steering system. Summary of the Invention

[0004] An example steer-by-wire (SBW) system for a vehicle includes: a steering wheel; a steering wheel actuator coupled to the steering wheel; road wheel actuators coupled to road wheels of the vehicle; machine-readable instructions; and a control device for executing the machine-readable instructions to: determine a steering wheel angle; cause the steering wheel actuator to apply a first feedback torque to the steering wheel based on the steering wheel angle and a target steering wheel angle; cause the steering wheel actuator to apply a second feedback torque to the steering wheel based on a user-applied torque greater than the first feedback torque, based on the steering wheel angle, the target steering wheel angle, and the user-applied torque; and cause the road wheel actuators to steer the vehicle based on the steering wheel angle.

[0005] An example non-transitory computer-readable medium includes instructions for causing a programmable circuit system to perform at least the following operations: determining a steering wheel angle of a vehicle's steering wheel; causing a steering wheel actuator of the vehicle to apply a first feedback torque to the steering wheel based on the steering wheel angle and a target steering wheel angle; causing the steering wheel actuator to apply a second feedback torque to the steering wheel based on a user-applied torque greater than the first feedback torque, based on the steering wheel angle, the target steering wheel angle, and the user-applied torque; and causing a road wheel actuator of the vehicle to steer the vehicle based on the steering wheel angle.

[0006] An example method for operating a steer-by-wire (SBW) system includes: determining a steering wheel angle of a vehicle's steering wheel; causing a steering wheel actuator of the vehicle to apply a first feedback torque to the steering wheel based on the steering wheel angle and a target steering wheel angle; causing the steering wheel actuator to apply a second feedback torque to the steering wheel based on a user-applied torque greater than the first feedback torque, the steering wheel angle, the target steering wheel angle, and the user-applied torque; and causing a road wheel actuator of the vehicle to steer the vehicle based on the steering wheel angle. Attached Figure Description

[0007] Figure 1 A schematic diagram of a vehicle including a steer-by-wire (SBW) system, based on an example described herein, is shown.

[0008] Figure 2 This is a flowchart illustrating example machine-readable instructions and / or example operations that can be executed, instantiated, and / or implemented by an example programmable circuit system. Figure 1 The SBW steering system.

[0009] Figure 3 This is a flowchart illustrating example machine-readable instructions and / or example operations that can be executed, instantiated, and / or implemented by an example programmable circuit system. Figure 1 The SBW steering system.

[0010] Figure 4 A schematic diagram showing the angle and torque curves of an example cooperative control system without target value correction functionality is provided.

[0011] Figure 5 A schematic diagram showing the angle and torque curves of a cooperative control system with target value correction function is presented.

[0012] Figure 6 A schematic diagram showing the angle and torque curves of the cooperative control system in manual mode and cooperative steering feel mode.

[0013] Figure 7 This is a block diagram of an example processing platform, which includes a programmable circuit system structured to execute, instantiate, and / or implement example machine-readable instructions and / or perform... Figure 2 and Figure 3 Example operations to implement Figure 1 The steer-by-wire system in the middle.

[0014] Typically, the same reference numerals will be used throughout the accompanying drawings and written description to refer to the same or similar parts. The drawings are not necessarily drawn to scale. Detailed Implementation

[0015] Modern vehicles typically include advanced features (e.g., functions) to enable autonomous or semi-autonomous driving. Known solutions offer drivers various methods to regain manual control of the vehicle's steering system. In one known example, the driver can completely deactivate the autonomous function, for example, by pressing a switch, pressing a deceleration pedal (e.g., the brake pedal), or applying torque to the steering wheel greater than a predetermined torque threshold. In other known examples, the driver can temporarily override a steering wheel angle target defined by a path-following function by applying a desired steering wheel angle. When the driver releases the steering wheel, the vehicle will follow the angle target defined by the path-following function. Possible schemes that affect the vehicle's lateral control without completely terminating (e.g., deactivating) the vehicle's autonomous control are often referred to as cooperative control.

[0016] In addition, modern vehicles are typically equipped with a steer-by-wire (SBW) system. SBW eliminates the direct mechanical connection between the steering wheel and the road wheels. SBW utilizes at least two actuators: a steering wheel actuator that generates feedback torque for the driver at the steering wheel; and road wheel actuators that adjust at least one (but usually several) steerable road wheels to the desired position. The feedback torque provides the driver with feedback regarding the vehicle's lateral control. To determine the feedback torque corresponding to the vehicle's lateral control, the SBW includes control equipment that performs a feedback algorithm for this purpose.

[0017] Because the SBW steering system differs significantly from previous mechanically coupled steering systems (such as electric power steering (EPS) systems), for example in the potential independent control of the steering wheel and road wheels, previous methods of cooperative control are not easily transplanted.

[0018] Therefore, it is necessary to be able to use the SBW steering system within the framework of cooperative control. Steering input needs to be provided simultaneously by the driver and according to the route-following function, thus requiring adjustment of vehicle lateral control based on a smooth transition between these input methods, thereby improving driver comfort compared to previous methods.

[0019] The example described herein provides a method for cooperative control of a SBW (Steering By-Wheel) system for a vehicle. The SBW system includes at least one steering wheel, a steering wheel actuator coupled to the steering wheel, a steering wheel sensor, road wheel actuators coupled to at least one steerable road wheel of the vehicle, and a control device. The control device is coupled at least to the steering wheel actuator, the steering wheel sensor, and the road wheel actuators. The control device executes at least one algorithm for controlling the steering wheel actuator and for adjusting the road wheel actuators and is coupled to a vehicle control device. The vehicle control device performs at least a partially autonomous or fully autonomous route-following function. The method includes at least the following operations: In a first operation, the control device receives a target angle of the steering wheel from the vehicle control device based on the route-following function. In a second operation, the control device controls the steering wheel in such a way that the steering wheel is adjusted via the steering wheel actuator according to the target angle. In a third operation, the driver can adjust the steering wheel to different steering wheel angles by applying additional driver torque. In a fourth operation, the steering wheel sensor detects the steering wheel angle. In a fifth operation, the control device applies feedback torque to the steering wheel via the steering wheel actuator. The feedback torque depends on the difference between the actual steering wheel angle and the target angle. In the sixth operation, the control device determines the target road wheel angle for at least one steerable road wheel of the vehicle based on the steering wheel angle. In the seventh operation, the control device determines the control signal for the road wheel actuator corresponding to the desired road wheel angle and outputs it to the road wheel actuator.

[0020] The example method is based on the understanding that the driver can apply additional driver torque to the steering wheel, thereby moving the steering wheel to an angle different from the target angle. This means that the steering wheel can be moved both autonomously or semi-autonomously via path-following functionality and simultaneously manually by the driver. This achieves coordinated control of the vehicle's lateral movement.

[0021] In some examples, the torque applied by the steering wheel actuator can be limited by a control device. This simplifies applying additional driver torque to the steering wheel. Furthermore, the fact that the feedback torque depends on the difference between the steering wheel angle and the target angle creates a mild but deviation-related feedback at the steering wheel for the driver regarding the deviation from the target angle. The greater the deviation from the target angle, the stronger the feedback, and the greater the likelihood that the driver will be driven toward the target angle based on the feedback torque. If the driver still wishes to deviate from the target angle, this is still possible, but with increasing deviation, greater effort (e.g., higher driver torque) is required.

[0022] In some examples, the feedback torque can be proportional to the difference between the steering wheel angle and the target angle. In some examples, the feedback torque can also be a non-linear function of the difference between the steering wheel angle and the target angle. In some examples, the function causes a higher difference between the steering wheel angle and the target angle to generate a higher feedback torque.

[0023] The described example method enables precise, adjustable, and consistent tuning of the control device. This allows for torque control to be configured with feedback torque, enabling the driver to simultaneously return to the target angle desired by the route-following function, provided the driver first deviates from the target angle by providing additional torque. The example method provides consistent and natural feedback behavior to the driver during cooperative control mode. This improves driver comfort compared to previous methods.

[0024] Furthermore, the examples described herein provide an SBW steering system for a vehicle. The SBW steering system includes at least one steering wheel, a steering wheel actuator coupled to the steering wheel, a steering wheel sensor, road wheel actuators coupled to at least one steerable road wheel of the vehicle, and a control device. The control device is coupled at least to the steering wheel actuator, the steering wheel sensor, and the road wheel actuators. The control device executes at least one algorithm for controlling the steering wheel actuator and for adjusting the road wheel actuators and is coupled to a vehicle control device.

[0025] The vehicle control equipment is configured to perform at least semi-autonomous or fully autonomous route following functionality. The control equipment is at least configured to receive a target steering wheel angle from the vehicle control equipment and control the steering wheel in such a manner that the steering wheel is adjusted according to the target angle via a steering wheel actuator, thereby allowing the driver to adjust the steering wheel to different steering wheel angles by applying additional driver torque. Steering wheel sensors are configured to detect the steering wheel angle assigned to their road wheels.

[0026] The control device is also configured to apply feedback torque to the steering wheel via a steering wheel actuator. The feedback torque depends on the difference between the steering wheel angle and the target angle. The control device is further configured to determine a target road wheel angle for at least one steerable road wheel based on the steering wheel angle, determine a control signal for the road wheel actuator corresponding to the target road wheel angle, and output the control signal to the road wheel actuator. The advantages achieved by the example method described herein are also achieved in a corresponding manner by the SBW steering system.

[0027] The vehicle's SBW steering system is understood as the vehicle's conventional SBW steering system, not an auxiliary steering system, which is achieved through torque control of the drive units and / or reduction gears allocated to the respective road wheels. In this context, the drive unit is understood as an electric motor operating accordingly, each of which is allocated to at least one road wheel and is used to drive the vehicle rather than to lateral guide it. Instead, the vehicle's drive unit is separate from the road wheel actuators and their electric motors.

[0028] The SBW steering system includes at least one road wheel actuator coupled to at least one steerable road wheel. In some examples, the road wheel actuator may also be coupled to several steerable road wheels, for example, via a rack.

[0029] In some examples, the vehicle may include several road wheel actuators, each individually coupled to several steerable road wheels. This increases the configurability of the SBW steering system.

[0030] In some examples, the vehicle may also include separate individual road wheel actuators associated with at least some of the vehicle's steerable road wheels. This means that the corresponding steerable road wheel can be controlled independently of the other steerable road wheels for lateral control of the vehicle based on the orientation of the individual road wheel. For example, this allows the individual steerable road wheels to have different orientations, such as camber or slant positions relative to a track position defined by the steering wheel angle. This means that the corresponding steerable road wheel is intentionally deviated from the track position corresponding to the driver's steering input and / or follow function. This may be advantageous, for example, if the vehicle's individual road wheels have a high level of slippage, for example, due to ground conditions (e.g., during off-road driving or similar situations).

[0031] In some examples, lateral control of the vehicle may be at least partially based on the driver's steering input, for example, the driver applying that steering input to the steering wheel to steer the vehicle in a specific direction. In some examples, lateral control of the vehicle may also be based on the following function of the vehicle control equipment. The following function adjusts the lateral control of the vehicle in a semi-autonomous or autonomous manner, thereby performing driving control of the vehicle in a way that achieves a destination predefined or determined by the driver. Typically, the route following function utilizes environmental data and / or position data and / or vehicle data, which are recorded via the vehicle's environmental sensors and / or speed and / or speed change sensors or determined via a position signal receiver. For example, the route following function may steer the vehicle based on the distance traveled on the road and adjust the lateral control of the vehicle for this purpose. Therefore, based on the following function, there is a target angle for each control interval, and the vehicle's steering wheel will be controlled according to this target angle so that the vehicle follows the expected trajectory determined by the following function. This target angle is then transmitted as a target angle request from the following function of the driving control equipment to the control equipment of the SBW steering system.

[0032] In some examples, the route-following function can also be used to perform other comfort features, such as lane departure warning systems or similar functions. Additional comfort features can also affect the vehicle's lateral control, for example, to prevent unintended lane changes.

[0033] The steering wheel actuator is configured to apply torque to the steering wheel at least indirectly (e.g., via a steering column coupled to the steering wheel). The torque generated by the steering wheel actuator is also used to provide torque feedback to the driver via lateral control of the vehicle. Typically, the steering wheel actuator includes an electric motor for applying torque to the steering wheel. For example, the electric motor may include a winding set having three windings (e.g., a three-phase winding set). In some examples, the electric motor may also include more than one winding set.

[0034] The steering wheel sensor is configured to detect the steering wheel angle relative to a reference position, such as zero position (e.g., corresponding to a straight line). In some examples, the steering wheel sensor may also be configured to detect the steering wheel speed during rotation. The steering wheel sensor transmits the recorded measurement data to a control device. The steering wheel sensor may be directly coupled to the steering wheel, but it may also be coupled to the steering column, as the steering column is rigidly coupled to the steering wheel, and therefore rotation of the steering wheel is directly translated into rotation of the steering column.

[0035] The SBW steering system may also include wheel angle sensors. These sensors are assigned to at least one steerable road wheel of the vehicle and are configured to directly or indirectly detect the wheel angle of the assigned road wheel about the vehicle's vertical axis. Furthermore, the wheel angle sensors are coupled to a control device and configured to transmit recorded measurements to the control device. The detected wheel angles of the steerable road wheels can be used to accurately characterize the vehicle's condition, such as changes in the vehicle's lateral speed. Additionally, based on the wheel angles detected by the wheel angle sensors, the control device can determine whether the vehicle is being guided according to a desired steering input. The wheel angle sensors may also be part of the road wheel actuators, for example, as position sensors that detect the position of the rack.

[0036] In addition, wheel speed sensors can be provided, which can be used by control equipment to determine the vehicle speed, at least indirectly, based on the recorded measurements. This allows control equipment to accurately characterize the vehicle configuration for corresponding driving conditions. For example, based on the recorded speed, control equipment can determine wheel-specific slip. Wheel slip refers to the deviation of the tire tread from the road surface that is in frictional contact with the corresponding wheel, whereby the tangential force counteracts traction. Traction refers to the transfer of the traction force used to drive the vehicle to the ground. A certain amount of wheel slip occurs when the vehicle is powered, for example, depending on road conditions and the type of tires. However, if wheel slip becomes excessive, the vehicle can no longer be accurately guided according to steering input.

[0037] For example, a vehicle can also be characterized based on its current speed change at a specific point in time. The control equipment then considers these parameters when determining the correct feedback torque to be applied from the steering wheel actuators to the steering wheel in order to provide feedback to the vehicle's driver regarding lateral control. Other parameters that the control equipment may consider when determining the correct feedback torque include, but are not limited to, the measured or estimated restoring torque of the road wheels and / or the rack and pinion forces applied to the rack by the road wheel actuators.

[0038] The algorithm for controlling the steering wheel actuator and adjusting the road wheel actuator may include at least one control loop with feedback. This means that the control device may include at least one control loop to manage the rotation of the steering wheel according to the target angle requirement of the following function. Then, as part of the algorithm, the control device also considers the steering wheel angle detected by the steering wheel sensor with respect to a reference position (e.g., zero position corresponding to a straight line). Based on the comparison of the steering wheel angle with the target angle requirement, a control signal is determined, which is output to the steering wheel actuator to cause an adjusted rotation of the steering wheel.

[0039] In some examples, if the driver stops applying additional driver torque, the control device returns the steering wheel to the target angle via the steering wheel actuator. This creates a defined transition of cooperative control when manual steering wheel operation ceases. Therefore, the transition between a configuration of simultaneous manual and autonomous steering wheel control and a configuration of fully autonomous steering wheel control is smooth and fluid. Consequently, there are no abrupt changes in lateral control of the vehicle, thus improving driver comfort.

[0040] In some examples, the feedback torque is limited based on the maximum permissible feedback torque of the electric motor of the steering wheel actuator. This prevents the electric motor from over-tensioning the steering wheel actuator. Furthermore, limiting the feedback torque also allows the driver to apply torque to the steering wheel to influence the steering wheel angle.

[0041] Typically, the maximum permissible feedback torque within a control system can be configured using control devices and / or steering wheel actuators, for example, in software. It is important to distinguish this maximum permissible feedback torque from the maximum available feedback torque that the steering wheel actuators can apply, which is usually higher than the maximum permissible feedback torque. The maximum permissible feedback torque is set lower to avoid applying excessive stress to the steering wheel actuators and to limit the feedback torque in a way that allows the driver to comfortably overcome it.

[0042] The limitation of feedback torque allows the force that a driver can typically apply to exceed the feedback torque. This ensures that the driver can autonomously adjust the steering wheel according to the deviation of the steering wheel angle desired by the driver.

[0043] In some examples, if the feedback torque required by the control system is greater than the maximum permissible feedback torque during the period when the driver applies torque, the control device adjusts the target angle of the steering wheel to the corrected target angle. This prevents the steering wheel from suddenly bouncing back upon release. In some examples, the feedback torque is measured as the difference between the steering wheel angle and the target angle. In some examples, as explained earlier, the feedback torque is typically limited. This can result in the difference between the steering wheel angle and the original target angle requiring such a high feedback torque that it exceeds the feedback torque limit. If the driver turns the steering wheel too far away from the target angle, such that the difference between the steering wheel angle and the target angle results in a feedback torque exceeding the maximum permissible feedback torque, the difference between the maximum permissible feedback torque and the feedback torque requested by the controller is determined as the incremental torque (Δ torque). In this case, the target angle is adjusted based on the incremental torque to obtain the corrected target angle. Therefore, the feedback torque specified by the difference is reduced. This results in the feedback torque being less than the limit. This ensures that the corrected target angle follows the angle specified by the driver (e.g., the target angle). If the driver releases the steering wheel and no longer applies any driver torque to it, the calibrated target angle is close to the steering wheel angle (e.g., the angle of rotation). Therefore, when the driver releases the steering wheel, it does not suddenly move to the target angle, but is slowly guided to the calibrated target angle.

[0044] In some examples, a PID controller or similar device can be used to perform the adjustment of the target angle, thereby subtracting the incremental torque from the corrected target angle over a time interval. Therefore, the change in steering wheel angle is relatively slow. Determining the corrected target angle based on the incremental torque may depend on additional parameters, such as the distance between the target angle and the corrected target angle, or the rate of change of the target angle.

[0045] In some examples, the control device may determine the target angle difference between the corrected target angle and the target angle (e.g., incremental reset angle). To adjust the steering wheel control back to the target angle without exceeding the maximum permissible feedback torque of the electric motor, the target angle difference needs to be subtracted from the corrected target angle over a time interval, ensuring a return to the target angle after the time interval. Therefore, the corrected target angle slowly moves back to the target angle.

[0046] Feedback on the target angle can also be performed by the PID controller of the control device. The difference in target angle subtracted from the corrected target angle can be limited to ensure smooth, continuous, and fluid steering wheel control. This improves driver comfort when the vehicle is being laterally guided. The angle subtracted at each time step of the time interval can alternatively be a constant angle value or a value dependent on the difference between the corrected target angle and the original target angle. In some examples, the added angle can also be added at any time (e.g., regardless of whether the feedback torque has reached the maximum permissible reset torque). Control devices configured in this way allow for individual tuning of the control device's behavior and the way the steering wheel returns to the target angle. Furthermore, this avoids the need for control devices with large damping values.

[0047] In some examples, the control unit causes the steering wheel actuator to return the steering wheel to a target angle based on a steering feel algorithm. In purely manual steering, the steering feel algorithm is also used to adjust the steering wheel according to the target angle. In manual control mode, when the driver releases the steering wheel, the steering feel algorithm returns the steering wheel to a centered position (e.g., the steering wheel angle is zero degrees). The measured steering wheel angle is included as a primary variable in the steering feel algorithm. In some examples, the steering feel algorithm is configured such that the feedback torque also increases with increasing distance from the centered position. Typically, the maximum permissible feedback torque calculated by the steering feel algorithm is small, allowing the driver to comfortably overdirect this feedback torque, thereby turning the steering wheel to the desired steering angle according to steering preference.

[0048] In the Co-Steering Feel Control mode, the target angle of the follow function is subtracted from the detected steering wheel angle (e.g., rotation angle). Instead of a fixed steering angle, the result is used in the steering feel algorithm. Therefore, when the steering wheel is released, the steering feel algorithm will now return the steering wheel to the target angle of the follow function. If the driver turns the steering wheel away from the target angle of the follow function, this also increases the feedback torque relative to the deflection (e.g., the difference between the target angle of the follow function and the detected steering wheel angle). Advantageously, this design ensures that there is generally no need for additional feedback torque limiting. This is made possible by the fact that the maximum permissible feedback torque is low enough to allow the driver to overcome the feedback torque. The steering feel algorithm can be adjusted according to its parameters. This can affect the accuracy of the follow function and the speed of feedback to the center position or target angle in the Co-Steering Feel Control mode when the driver releases the steering wheel.

[0049] The control device determines a target wheel angle for at least one steerable road wheel based on the steering wheel angle. Then, the control device sends a control signal corresponding to the target wheel angle to the road wheel actuators. Therefore, the steering wheel angle is used for lateral control of the vehicle based on the steerable road wheels. Because the steering wheel angle can be adjusted either through the autonomous or semi-autonomous route-following function of the vehicle control device, or by the driver based on corresponding driver torque, lateral control of the vehicle can be achieved within the framework of coordinated steering wheel control, based on both simultaneous input methods.

[0050] In some examples, the control device determines the target wheel angle based at least on a lookup table. In this process, it also considers the detected or determined vehicle speed. By taking the vehicle speed into account, oversteer is prevented by adjusting the angles of the steerable road wheels based on the vehicle's speed, even if the angle does not correspond to the vehicle's speed.

[0051] Vehicle speed can be determined using wheel speed sensors. Additionally, wheel angle sensors can be used to detect the wheel angle of the steerable road wheels about the vehicle's vertical axis and transmit it to control equipment. Alternatively, or in combination, vehicle speed can also be determined based on received position signals. In another alternative, vehicle speed can also be determined based on vehicle speed and / or speed change sensors.

[0052] In some examples, the control device determines the target wheel angle based at least on an algorithm used to determine the target wheel angle in the case of pure manual steering (e.g., manual control mode).

[0053] According to another aspect, this disclosure also relates to a computer program product comprising instructions that, when executed by a computer, cause the computer to perform the methods described herein. The benefits achieved by the processes described herein are also achieved by the computer program product in a corresponding manner.

[0054] According to an additional aspect, this disclosure also relates to a computer-readable storage medium comprising commands that, when executed by a computer, cause the computer to perform the methods described herein. The benefits achieved by the processes described herein are also achieved by the computer-readable storage medium in a corresponding manner.

[0055] According to another aspect, some examples of this disclosure relate to a vehicle having an SBW steering system as described herein or an SBW steering system operable by the methods described herein. The benefits achieved by the procedures described herein are also achieved by the vehicle in a corresponding manner.

[0056] For the purposes of this disclosure, the vehicle may include land vehicles, namely, in particular off-road vehicles and highway vehicles (such as passenger cars, buses, trucks, and other commercial vehicles). The vehicle may be manned or unmanned. The vehicle is at least partially electrically driven (e.g., having an electric motor as a drive unit). In addition, the vehicle may also have an optional combustion engine.

[0057] All features explained about each aspect can be individually combined or (sub)combined with other aspects.

[0058] The following detailed description, taken in conjunction with the accompanying drawings (where like reference numerals denote like elements), is intended to describe various examples, not to represent the only examples. Each example described in this disclosure is intended only as an example or illustration and should not be construed as superior to or more advantageous than other examples. The illustrative examples included herein are not exhaustive and do not limit the claimed subject matter to the exact forms disclosed. Various variations of the examples will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other examples and applications without departing from the spirit and scope of the described examples. Therefore, the described examples are not limited to those shown but have the broadest range of applications compatible with the principles and features disclosed herein.

[0059] All features disclosed below in connection with the examples and / or figures may be combined with features of various aspects of this disclosure, either individually or in any sub-combination, provided that the resulting combination of features is reasonable to a person skilled in the art.

[0060] For the purposes of this disclosure, the phrase "at least one of A, B, and C" means, for example, (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), and if more than three elements are listed, all other possible combinations are included. In other words, the term "at least one of A and B" generally means "A and / or B," i.e., "A" alone, "B" alone, or "A and B."

[0061] Figure 1 A schematic diagram of a vehicle 10 with an SBW steering system 12 according to an example described herein is shown. The vehicle 10 includes a component 14 comprising both the SBW steering system 12 and at least one vehicle control device 16. The vehicle control device 16 executes at least one algorithm with a route-following function 18. This means that, based on the destination to be reached by the vehicle 10, the algorithm with the route-following function 18 determines the trajectory of the vehicle 10, for example, based on the road on which the vehicle 10 will travel. Therefore, the algorithm with the route-following function 18 determines the target angle of the steering wheel 20 of the SBW steering system 12. Thus, the steering wheel 20 should deflect from a reference position according to the target angle so that the lateral control of the vehicle 10 corresponds to the trajectory.

[0062] In addition to the SBW steering system 12, the vehicle 10 also includes a steerable road wheel 22. The steerable road wheel 22 is coupled to a common rack 24. The common rack 24 is movable from a reference position (e.g., zero position), which causes steering movement of the steerable road wheel 22. For example, the steerable road wheel 22 can deflect from a straight alignment of the vehicle 10 to cause the vehicle 10 to execute a curve.

[0063] For movement of rack 24, SBW steering system 12 includes a single road wheel actuator 26 that collectively affects the alignment of two steerable road wheels 22 (e.g., front wheels) of vehicle 10. In the illustrated example, road wheel actuator 26 is coupled to rack 24. In some examples, road wheel actuator 26 may also be coupled to steerable road wheels 22 in other ways to affect their orientation.

[0064] In some examples, several road wheel actuators 26 may also be provided, each individually coupled to the steerable road wheel 22. The advantage of this is that the steerable road wheels 22 do not move together, meaning that the steerable road wheels 22 can be individually aligned. For example, an individual steerable road wheel 22 may then employ a dedicated off-track position, such as for a specific driving situation (e.g., off-road driving). An off-track position means that the steerable road wheel 22 is not aligned according to the nominal track position defined by the steering wheel angle of the steering wheel 20.

[0065] Despite Figure 1 The example is not shown, but the vehicle 10, SBW steering system 12 and component 14 may include other steerable road wheels 22, such as rear wheels coupled to an additional common rack or to an individual road wheel actuator 26.

[0066] Each road wheel actuator 26 includes an electric motor 28. The electric motor 28 includes at least one set of windings. Each set of windings is configured such that a phase current can be used to drive the rotor of the electric motor 28. The rotor can then be coupled to a corresponding component of the SBW steering system 12 (such as rack 24), thereby enabling the steerable road wheel 22 to move. Typically, the electric motor 28 may also have more than one set of windings. Typically, each set of windings is three-phase, making the electric motor 28 at least three-phase. If several sets of windings are present, the sets of windings allow the rotor of the electric motor 28 to move independently of the other sets of windings. This means that the sets of windings are independent of each other.

[0067] In some examples, vehicle 10 also includes wheel speed sensors 31, which can be used to record the rotational speed of the road wheels 22 in the circumferential direction (e.g., the rolling direction). For example, based on the recorded speeds, wheel-specific slippage can be determined, which makes it possible to characterize vehicle 10 according to driving conditions. In some examples, each road wheel 22 is assigned a wheel speed sensor 31.

[0068] The SBW steering system 12 also includes a wheel angle sensor 30. The wheel angle sensor 30 is configured to detect the wheel angle of the steerable road wheel 22 relative to the vertical axis of the vehicle and transmit it to the control device 40 and / or the road wheel actuator 26 of the SBW steering system 12. The wheel angle sensor 30 can also detect the wheel angle indirectly, for example, via the detected position of the rack 24. For example, the wheel angle detected by the wheel angle sensor 30 can then be used for control of the road wheel actuator 26.

[0069] The driver of vehicle 10 can use steering wheel 20 to input steering to steer vehicle 10 in a desired direction. Steering wheel 20 is coupled to steering column 32 of SBW steering system 12. Steering column 32 defines the axis of rotation about which steering wheel 20 can rotate. Steering wheel actuator 34 of SBW steering system 12 is coupled to steering wheel 20 via steering column 32. Steering wheel actuator 34 includes electric motor 36. Electric motor 36 of steering wheel actuator 34 also includes at least one winding set. Each winding set is three-phase and configured to drive the rotor of electric motor 36. Therefore, electric motor 36 can provide feedback torque to the driver at steering wheel 20 of vehicle 10, thereby providing the driver with feedback on lateral control of vehicle 10.

[0070] The SBW steering system 12 also includes at least one steering wheel sensor 38, which is at least indirectly coupled to the steering wheel 20, for example, via the steering column 32. Each steering wheel sensor 38 is configured independently of the other steering wheel sensors 38 to detect the driver's steering input based on the steering wheel angle (e.g., rotation angle) and / or steering wheel speed of the steering wheel 20 relative to a reference position. Figure 1 In the illustrated example, the steering wheel sensor 38 is shown coupled to the steering column 32 because the steering wheel 20 is rigidly coupled to the steering column 32, and therefore rotation of the steering wheel 20 is directly translated into rotation of the steering column 32. Typically, the steering wheel sensor 38 may be coupled to the steering wheel 20 itself, for example, to a basic component of the steering wheel 20, rather than to the steering column 32. In such examples, the steering wheel sensor 38 may directly detect rotation of the steering wheel 20 itself.

[0071] The SBW steering system 12 also includes a control device 40 with a data processing device 42. The control device 40 is coupled at least to the vehicle control device 16, the road wheel actuator 26, the wheel angle sensor 30, the steering wheel actuator 34, and the steering wheel sensor 38. The data processing device 42 executes at least one algorithm 44 for controlling the steering wheel actuator 34 and for controlling the road wheel actuator 26. Furthermore, the control device 40 executes algorithms for adjusting the steerable road wheels 22 and for setting appropriate feedback torque at the steering wheel 20.

[0072] The SBW steering system 12 is configured for the coordinated control of the steering wheel 20. This means that the control device 40 can be used to output corresponding control signals to the steering wheel actuator 34 to autonomously or semi-autonomously apply torque to the steering wheel 20. However, the steering wheel 20 is also configured such that the driver can apply additional driver torque to it. Both the torque applied by the steering wheel actuator 34 and the torque applied by the driver adjust the steering wheel angle of the steering wheel 20. The steering wheel angle is detected by the steering wheel sensor 38, which the control device 40 uses to set the steerable road wheels 22 according to the detected steering wheel angle. The control device 40 sends corresponding control signals to the road wheel actuators 26, which induce torque to align the steerable road wheels 22. For example, the torque output by the road wheel actuators 26 can act on the rack 24, which then ultimately causes the alignment of the steerable road wheels 22. In an example where the road wheel actuators 26 are assigned to corresponding steerable road wheels 22, a corresponding control signal is transmitted from the control device 40 to each road wheel actuator 26.

[0073] In some examples, vehicle 10 includes at least one position signal receiver 46 and a speed change sensor 48, also coupled to control device 40. Position signals from a global navigation satellite system can be received via position signal receiver 46, allowing control device 40 to determine the position of vehicle 10 based on the received position signals. For example, the speed of vehicle 10 can also be indirectly determined based on the position of vehicle 10. Vehicle speed and / or speed change values ​​of vehicle 10 can be accurately detected along three orthogonally oriented directions via speed and speed change sensor 48 and transmitted to control device 40. Therefore, control device 40 can accurately characterize the driving status of vehicle 10 at a given control time.

[0074] In some examples, the control device 40 may consider other parameters of the vehicle 10, such as vehicle speed or speed change values, when issuing control signals to the road wheel actuators 26. These values ​​may also be considered when adjusting the torque applied to the steering wheel 20 by the steering wheel actuators 34. Furthermore, the vehicle control device 16 may consider determined vehicle parameters indirectly recorded by the position signal receiver 46 and the speed and speed change sensors 48 within the framework of the algorithm of the follow function 18. In some examples, the SBW steering system 12 may include several components of the same type and substantially the same function, such as several steering wheel sensors 38, thereby ensuring redundancy.

[0075] Figure 2 A simplified schematic diagram of a method 50 for cooperative control of an SBW steering system 12, which is part of component 14 of vehicle 10, is shown according to an example. Optional operations are shown in dashed lines.

[0076] In optional operation S1 of method 50, a target angle is determined by an algorithm with a following function 18 of the driving control device 16. The target angle describes how to steer the vehicle 10 so that it follows a fixed trajectory. The trajectory depends on a predefined destination of the vehicle 10. For example, the destination may be defined by user input. To determine the target angle, the vehicle control device 16 may consider environmental parameters of the vehicle 10 (such as road conditions) as well as parameters of the vehicle 10 itself (such as vehicle speed).

[0077] Method 50 then includes operation S2, wherein the control device 40 of the SBW steering system 12 receives a target angle from the vehicle control device 16 based on an algorithm having a following function 18. In other words, the vehicle control device 16 transmits the target angle requirement to the control device 40, causing it to set the steering wheel 20 according to the target angle determined by the vehicle control device 16.

[0078] In operation S3, control device 40 controls steering wheel 20 such that steering wheel 20 is adjusted according to a target angle via steering wheel actuator 34. In some examples, the torque output of steering wheel actuator 34 is limited by control device 40. The driver can adjust steering wheel 20 to different steering wheel angles by applying additional driver torque. This means that steering wheel actuator 34 can apply maximum permissible torque to steering wheel 20 via electric motor 36 to set steering wheel 20 according to the target angle defined by the target angle requirement. Limiting the torque applied by steering wheel actuator 34 simplifies the influence of the driver's application of driver torque. The driver can adjust the steering wheel angle via additional driver torque on steering wheel 20, and thus exert additional manual influence on the lateral control of vehicle 10 within the framework of coordinated control of steering wheel 20.

[0079] Operation S3 represents the control of the target angle requirement, and its specific design is specified by operations S4 to S10.

[0080] Then, in operation S4, the steering wheel sensor 38 detects the steering wheel angle of the steering wheel 20 and transmits it to the control device 40.

[0081] Based on the steering wheel angle detected by the steering wheel sensor 38, the control device 40 then determines the feedback torque in operation S5. It then sends a corresponding actuator signal to the steering wheel actuator 34, causing it to apply the feedback torque to the steering wheel 20. In this example, the control device 40 determines the feedback torque based on the difference between the steering wheel angle of the steering wheel 20 detected by the steering wheel sensor 38 and the target angle. The feedback torque is a function of the difference between the steering wheel angle of the steering wheel 20 and the target angle. In some examples, the feedback torque is proportional to the difference. However, other dependencies can also be used. This means that the greater the deviation of the steering wheel angle from the target angle, the greater the feedback torque and the more the steering wheel 20 is driven towards the target angle. This allows the driver to apply manual driver torque to the steering wheel 20, resulting in a deviation from the target angle. This achieves continuous and smooth cooperative control of the steering wheel 20 and thus lateral control of the vehicle 10.

[0082] Operation S5 can be further implemented by optional operation S6, in which the feedback torque detected by the control device 40 is limited to the maximum permissible feedback torque. This ensures that the driver is not prevented from setting the desired steering wheel angle due to excessive feedback torque.

[0083] In operation S7 of method 50, if the driver releases the driver torque applied to the steering wheel 20, the control device 40 returns the steering wheel 20 to the target angle via the steering wheel actuator 34. This means that the driver can apply torque to control the steering wheel 20, causing the steering wheel angle to deviate from the target angle. However, if the driver stops or reduces the torque, the steering wheel 20 returns to the direction of the target angle. This achieves a smooth transition from a cooperative control mode of the steering wheel 20 by the driver and the control device 40 to another mode that uses algorithm 44 for controlling the steering wheel actuator 34 and the road wheel actuator 26.

[0084] Then, according to optional operation S8, method 50 can provide adjusting the target angle of the steering wheel 20 to a calibrated target angle via control device 40, provided that the driver applies torque to the steering wheel 20 in a manner such that feedback cannot be provided for the portion of torque in the form of excessive torque, since the feedback torque corresponds to the maximum permissible feedback torque. Control device 40 continues to adjust the target angle of the steering wheel 20 until the feedback torque is less than the maximum permissible feedback torque of the electric motor 36 of the steering wheel actuator 34 (i.e., the limit of the feedback torque). For particularly high torque applied by the driver, the difference between the steering wheel angle detected by the steering wheel sensor 38 and the target angle increases. This results in an increase in feedback torque, since feedback torque is proportional to the difference. Because the feedback torque is limited based on the maximum feedback torque allowed by the electric motor 36 of the steering wheel actuator 34, if the driver applies excessive torque, a feedback torque corresponding to the excessive torque cannot be applied. In such examples, control device 40 manually adjusts the target angle to reduce the difference and thus reduce the feedback torque.

[0085] According to the subsequent optional operation S9 of method 50, control device 40 aligns the corrected target angle established by the adjustment in operation S8 with the target angle. Depending on the difference between the corrected target angle and the target angle, control device 40 subtracts the incremental angle value at each time step until the corrected target angle corresponds to the target angle. Once the driver torque decreases and the driver of vehicle 10 no longer applies excessive torque, the corrected target angle can be backtracked to the target angle determined by vehicle control device 16. To ensure a smooth transition, only small adjustments are made to the corrected target angle within a single time period. This means that the amount by which control device 40 adjusts the corrected target angle within a single time period is limited. In some examples, the amount of the corrected target angle that can be adjusted within a single time period is predetermined. In some examples, the limit can be stored in a storage device coupled to control device 40. In some examples, the limit can be specified by user input. This achieves smooth feedback to the target angle, provided that the driver of vehicle 10 no longer applies excessive torque. This increases driver comfort.

[0086] In some examples, method 50 includes an optional operation S10, in which control device 40 returns steering wheel 20 to a target angle via steering wheel actuator 34 based on a steering feel algorithm. In the case of purely manual steering, control device 40 also uses the steering feel algorithm to adjust the feedback torque to the driver. Due to an optional torque limiter corresponding to optional operation S6, and because the steering feel algorithm typically requires only low torque, the feedback torque to the driver is limited. This means that the driver can apply additional driver torque to steering wheel 20 to deviate from the control of control device 40.

[0087] Here, the steering feel algorithm is extended in a way that the algorithm of control device 40 does not use the detected steering angle, but instead uses a value determined by subtracting the target angle from the steering wheel angle. Therefore, when the driver releases the steering wheel 20, the steering feel algorithm returns the steering wheel 20 to the target angle.

[0088] Method 50 further includes operation S13, wherein control device 40 determines a target wheel angle for at least one steerable road wheel 22 based on the steering wheel angle and outputs a control signal corresponding to the target wheel angle to road wheel actuator 26. Steering wheel sensor 38 can be used to detect the steering wheel angle of steering wheel 20. Because the steering wheel angle of steering wheel 20 is used to control road wheel actuator 26, both input methods for the coordinated control of steering wheel 20 are taken into account (e.g., autonomous control based on control device 40 (based on vehicle control device 16), and driver torque manually input by the driver of vehicle 10).

[0089] Operation S13 can be further implemented via optional operation S14, wherein the control device 40 determines the target wheel angle based at least on a lookup table. In this process, the control device 40 considers the detected or determined vehicle speed of the vehicle 10. The vehicle speed can be determined by using parameters directly recorded by the speed and speed change sensors 48 or based on the position of the vehicle 10 determined by the position signal receiver 46.

[0090] In some examples, operation S13 can be further implemented via optional operation S15, wherein the control device 40 determines the target wheel angle based at least on a vehicle lateral control algorithm. This vehicle lateral control algorithm defines the relationship between the steering wheel angle and the road wheel angle during manual driving.

[0091] Method 50 enables control of the steering wheel 20 for coordinated steering guidance via autonomous driving functions and manual input. The configuration of Method 50 ensures a smooth transition between different input methods. Furthermore, a smooth return is possible if manual input is stopped. In addition, inherent adjustments are considered to counteract excessive driver torque, preventing malfunctions (such as those caused by excessively high feedback torque requirements from the steering wheel actuator 34).

[0092] Figure 3 An example implementation of the target angle correction method 60 is shown. Although in the illustrated example, method 60 is implemented by angle controller 62, in some examples, method 60 may also be implemented by control device 40, PID controller, etc. Target angle correction method 60 includes operation S1, in which the target angle is initially determined and provided by an algorithm of vehicle control device 16 having path following function 18.

[0093] Because of the difference between the steering wheel angle and the target angle, there is an unlimited torque target value (M_unlimited) for the feedback torque to be provided to the steering wheel 20. As part of the target angle correction method 60, the control device 40 now checks at operation S2 whether the unlimited torque target value is greater than the maximum allowable feedback torque (M_Limit) of the steering wheel actuator 34.

[0094] If this is not the case, the corrected target angle (M_unlimited_corrected_target_angle) is the target angle to which the incremental feedback angle is added for the previous time interval. The incremental feedback angle corresponds to a portion of the target angle difference between the corrected target angle and the target angle. This yields a new value for the corrected target angle. Furthermore, the torque target value is fed to the steering wheel actuator 34, which generates feedback torque in operation S5 and applies it to the steering wheel 20.

[0095] If the unlimited torque target value is greater than the maximum permissible feedback torque, the incremental angle is determined at step S4 by the target value correction method 60. The incremental angle is determined by the difference (multiplied by a factor) between the unlimited torque target value and the maximum permissible feedback torque of the steering wheel actuator 34. In this example, the corrected target angle is the target angle obtained by subtracting the incremental feedback angle from the previous time interval. This yields a new value for the corrected target angle. Furthermore, in this example, the torque target value is the maximum permissible feedback torque. Again, the torque target value is fed to the steering wheel actuator 34, which generates the feedback torque at operation S5 and applies it to the steering wheel 20.

[0096] Figure 2 and Figure 3Example instructions and / or operations may be implemented using executable instructions (e.g., computer-readable instructions and / or machine-readable instructions) stored on one or more non-transitory computer-readable and / or machine-readable media. As used herein, the terms "non-transitory computer-readable medium," "non-transitory computer-readable storage medium," "non-transitory machine-readable medium," and / or "non-transitory machine-readable storage medium" are explicitly defined to include any type of computer-readable storage device and / or storage disk and exclude propagation signals and transmission media. Examples of such non-transitory computer-readable media, non-transitory computer-readable storage media, non-transitory machine-readable media, and / or non-transitory machine-readable storage media include optical storage devices, magnetic storage devices, hard disk drives (HDDs), flash memory, read-only memory (ROM), optical discs (CDs), digital versatile optical discs (DVDs), caches, random access memory (RAM) of any type, registers, and / or any other storage device or storage disk in which information may be stored for any duration (e.g., for extended time periods, permanently, transiently, temporarily buffered, and / or cached information). As used herein, the terms "non-transitory computer-readable storage device" and "non-transitory machine-readable storage device" are defined as including any physical (mechanical, magnetic, and / or electrical) hardware used to retain information for a period of time, but excluding signal propagation and transmission media. Examples of non-transitory computer-readable storage devices and / or non-transitory machine-readable storage devices include any type of random access memory, any type of read-only memory, solid-state memory, flash memory, optical disc, magnetic disk, disk drive, and / or redundant array of independent disks (RAID) system. As used herein, the term "device" refers to a physical structure, such as mechanical and / or electrical equipment, hardware, and / or circuitry, which may or may not be configured by computer-readable instructions, machine-readable instructions, etc., and / or manufactured to execute computer-readable instructions, machine-readable instructions, etc.

[0097] Combined with target value correction method 60, Figure 4 A schematic diagram 70 shows the angle and torque curves of the cooperative control without using the target value correction method 60. Time is plotted on the x-axis. In the upper subplot, the steering wheel angle is plotted on the y-axis, and in the lower subplot, the torque is plotted on the y-axis.

[0098] The driver determines and sets the target angle 72 using the follow function 18 of the driving control device 16. At time t1, the driver begins to apply additional driver torque to the steering wheel 20. This results in an actual steering wheel angle 74, which differs from the original target angle 72. In terms of torque, the driver torque results in an unlimited target torque value 76, which exceeds the maximum permissible feedback torque 78 of the steering wheel actuator 34. At time t3, the driver releases the steering wheel 20, and the actual steering wheel angle 74 decreases to the target angle 72 via the unlimited torque target value 76.

[0099] Figure 5 A schematic diagram 80 shows the angle and torque curves of the cooperative control system utilizing the target value correction method 60. Only the relationship with... Figure 4 The differences.

[0100] At time t2, the unlimited torque target value 76 exceeds the maximum permissible feedback torque 78 of the steering wheel actuator 34. The target value correction method 60 now applies an adjustment to the target angle to determine the corrected target angle 82. In this example, the corrected target angle 82 is equal to the target angle obtained by subtracting the previous control interval of the incremental reset angle. The incremental return angle corresponds to a portion of the target angle difference between the actual steering wheel angle 74 and the original target angle 72. Therefore, the corrected target angle 82 differs from both the original target angle 71 and the actual steering wheel angle 74.

[0101] After the driver releases the steering wheel 20, the corrected target angle 82 is returned to the original target angle 72 based on the unlimited torque target value 76.

[0102] Figure 6 A schematic diagram 90 shows the torque curves in manual and cooperative steering feel control modes. In manual control mode, corresponding to operation S15 of method 50, the feedback torque 92 to be applied by the steering wheel actuator 34 is shown. If the unlimited torque target value 76 exceeds the maximum permissible feedback torque 78 of the steering wheel actuator 34, an adjusted feedback torque curve 94 is generated for the target angle correction 96 of the corrected target angle 82. The feedback torque is a function of the difference between the actual steering wheel angle 74 and the target angle 72 of the follow function 18. For example, the functional dependency could be proportional to the difference, thereby taking into account corresponding factors to achieve the desired control behavior.

[0103] Figure 7This is a block diagram of an example programmable circuit system platform 700, which is configured to execute and / or instantiate example machine-readable instructions and / or example operations in the diagram [flowchart] to implement the examples disclosed herein. For example, the programmable circuit system platform 700 may be a control device, an electronic control unit (ECU), a self-learning machine (e.g., a neural network), or any other type of computing and / or electronic device.

[0104] The illustrated example programmable circuit system platform 700 includes a programmable circuit system 712. The illustrated example programmable circuit system 712 is hardware. For example, the programmable circuit system 712 may be implemented by one or more integrated circuits, logic circuits, field-programmable gate arrays (FPGAs), microprocessors, central processing units (CPUs), graphics processing units (GPUs), vision processing units (VPUs), digital signal processors (DSPs), and / or microcontrollers from any desired family or manufacturer. The programmable circuit system 712 may be implemented by one or more semiconductor-based (e.g., silicon-based) devices.

[0105] The illustrated example programmable circuit system 712 includes local memory 713 (e.g., cache, registers, etc.). The illustrated example programmable circuit system 712 communicates with main memories 714 and 716 via bus 718, the main memories including volatile memory 714 and non-volatile memory 716. Volatile memory 714 may be implemented using synchronous dynamic random access memory (SDRAM), dynamic random access memory (DRAM), RAMBUS® dynamic random access memory (RDRAM®), and / or any other type of RAM device. Non-volatile memory 716 may be implemented using flash memory and / or any other desired type of memory device. Access to the illustrated example main memories 714 and 716 is controlled by a memory controller 717. In some examples, the memory controller 717 may be implemented by one or more integrated circuits, logic circuits, microcontrollers from any desired family or manufacturer, or any other type of circuit system to manage the flow of data into and out of main memories 714 and 716.

[0106] The illustrated programmable circuit system platform 700 also includes an interface circuit system 720. The interface circuit system 720 can be implemented in hardware according to any type of interface standard, such as Controller Area Network (CAN), Ethernet interface, Universal Serial Bus (USB) interface, Bluetooth® interface, Near Field Communication (NFC) interface, Peripheral Component Interconnect (PCI) interface and / or Peripheral Component Interconnect Express (PCIe) interface.

[0107] In the illustrated example, one or more input devices 722 are connected to the interface circuit system 720. The input devices 722 allow users (e.g., human users, machine users, etc.) to input data and / or commands into the programmable circuit system 712. For example, the input devices 722 may be implemented as audio sensors, microphones, cameras (still or video), buttons, touchscreens, and / or voice recognition systems.

[0108] One or more output devices 724 are also connected to the interface circuitry 720 of the illustrated example. For example, the output devices 724 may be implemented by display devices (e.g., light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), liquid crystal displays (LCDs), in-plane switching (IPS) displays, touch screens, etc.), haptic output devices, and / or speakers. Thus, the interface circuitry 720 of the illustrated example typically includes a graphics driver card, a graphics driver chip, and / or a graphics processor circuitry (such as a GPU).

[0109] The illustrated example interface circuit system 720 also includes communication devices such as transmitters, receivers, transceivers, modems, residential gateways, wireless access points, and / or network interfaces to facilitate the exchange of data with external machines (e.g., any type of computing device) via network 726. For example, communication can be conducted via Ethernet connections, digital subscriber line (DSL) connections, telephone line connections, coaxial cable systems, satellite systems, beyond-line-of-sight wireless systems, line-of-sight wireless systems, cellular telephone systems, fiber optic connections, etc.

[0110] The illustrated example programmable circuit system platform 700 also includes one or more mass storage disks or devices 728 for storing firmware, software, and / or data. Examples of such mass storage disks or devices 728 include magnetic storage devices (e.g., floppy disks, drives, HDDs, etc.), optical storage devices (e.g., Blu-ray discs, CDs, DVDs, etc.), RAID systems, and / or solid-state storage disks or devices (such as flash memory devices and / or solid-state drives (SSDs)).

[0111] The machine-readable instructions 732, which can be implemented by the machine-readable instructions in the flowchart, can be stored in a mass storage device 728, a volatile memory 714, a non-volatile memory 716, and / or can be at least one removable non-transitory computer-readable storage medium (such as a CD or DVD).

[0112] This disclosure may refer to numbers and quantities. Unless otherwise stated, such numbers and quantities should not be considered as limitations, but rather as examples of possible numbers or quantities in conjunction with this disclosure. In this context, the term "plural / multiple" may also be used in this disclosure to refer to numbers or quantities. In this context, the term "plural / multiple" means any quantity greater than one, such as two, three, four, five, etc. The terms "approximately," "about," "close to," etc., indicate a specified value ±5%.

[0113] Although this disclosure has been introduced and described in conjunction with one or more examples, those skilled in the art will be able to make equivalent changes and modifications after reading and understanding this specification and the accompanying drawings.

[0114] This document discloses example methods and apparatus for cooperative control in steer-by-wire systems. Further examples and combinations thereof include the following: Example 1 includes a steer-by-wire (SBW) system for a vehicle, comprising: a steering wheel; a steering wheel actuator coupled to the steering wheel; road wheel actuators coupled to road wheels of the vehicle; machine-readable instructions; and a control device for executing the machine-readable instructions to: determine a steering wheel angle; cause the steering wheel actuator to apply a first feedback torque to the steering wheel based on the steering wheel angle and a target steering wheel angle; cause the steering wheel actuator to apply a second feedback torque to the steering wheel based on a user-applied torque greater than the first feedback torque, based on the steering wheel angle, the target steering wheel angle, and the user-applied torque; and cause the road wheel actuators to steer the vehicle based on the steering wheel angle.

[0115] Example 2 includes the SBW steering system according to Example 1, wherein if the torque applied by the user is greater than the maximum feedback torque of the steering wheel actuator, the control device causes the steering wheel actuator to apply a third feedback torque to the steering wheel based on the steering wheel angle, the torque applied by the user, and the corrected target steering wheel angle.

[0116] Example 3 includes the SBW steering system according to Example 2, wherein after the third feedback torque is applied, if the user-applied torque is released, the control device causes the steering wheel actuator to apply a fourth feedback torque to the steering wheel for a time interval.

[0117] Example 4 includes an apparatus according to any one or more of Examples 2 to 3, wherein the corrected target steering wheel angle is calculated based on the target steering wheel angle and the difference between the user-applied torque and the maximum feedback torque.

[0118] Example 5 includes a device according to any one or more of Examples 2 to 4, wherein the corrected target steering wheel angle is proportional to the difference between the torque applied by the user and the maximum feedback torque.

[0119] Example 6 includes a device according to any one or more of Examples 1 to 5, wherein the target steering wheel angle is based on the vehicle’s predetermined destination.

[0120] Example 7 includes a device according to any one or more of Examples 1 to 6, wherein the target steering wheel angle is based on the autonomous driving function of the vehicle.

[0121] Example 8 includes a device according to any one or more of Examples 1 to 7, wherein the target steering wheel angle is based at least on a lookup table.

[0122] Example 9 includes a non-transitory computer-readable medium comprising instructions for causing a programmable circuit system to perform at least the following operations: determining a steering wheel angle of a vehicle's steering wheel; causing a steering wheel actuator of the vehicle to apply a first feedback torque to the steering wheel based on the steering wheel angle and a target steering wheel angle; causing the steering wheel actuator to apply a second feedback torque to the steering wheel based on a user-applied torque greater than the first feedback torque, based on the steering wheel angle, the target steering wheel angle, and the user-applied torque; and causing a road wheel actuator of the vehicle to steer the vehicle based on the steering wheel angle.

[0123] Example 10 includes a non-transitory computer-readable medium according to Example 9, wherein if the user-applied torque is greater than the maximum feedback torque of the steering wheel actuator, the programmable circuitry causes the steering wheel actuator to apply a third feedback torque to the steering wheel based on the steering wheel angle, the user-applied torque, and the corrected target steering wheel angle.

[0124] Example 11 includes a non-transitory computer-readable medium according to Example 10, wherein after the third feedback torque is applied, if the user-applied torque is released, the programmable circuitry causes the steering wheel actuator to apply a fourth feedback torque to the steering wheel over a time interval.

[0125] Example 12 includes an apparatus according to any one or more of Examples 10 to 11, wherein the corrected target steering wheel angle is calculated based on the target steering wheel angle and the difference between the user-applied torque and the maximum feedback torque.

[0126] Example 13 includes an apparatus according to any one or more of Examples 10 to 12, wherein the corrected target steering wheel angle is proportional to the difference between the torque applied by the user and the maximum feedback torque.

[0127] Example 14 includes a device according to any one or more of Examples 9 to 13, wherein the target steering wheel angle is based on a predetermined destination of the vehicle.

[0128] Example 15 includes a device according to any one or more of Examples 9 to 14, wherein the target steering wheel angle is based on the autonomous driving function of the vehicle.

[0129] Example 16 includes an apparatus according to any one or more of Examples 9 to 15, wherein the target steering wheel angle is based at least on a lookup table.

[0130] Example 17 includes a method for operating a steer-by-wire (SBW) system, comprising: determining a steering wheel angle of a vehicle's steering wheel; causing a steering wheel actuator of the vehicle to apply a first feedback torque to the steering wheel based on the steering wheel angle and a target steering wheel angle; causing the steering wheel actuator to apply a second feedback torque to the steering wheel based on a user-applied torque greater than the first feedback torque, based on the steering wheel angle, the target steering wheel angle, and the user-applied torque; and causing a road wheel actuator of the vehicle to steer the vehicle based on the steering wheel angle.

[0131] Example 18 includes the method according to Example 17, wherein if the torque applied by the user is greater than the maximum feedback torque of the steering wheel actuator, the method further includes causing the steering wheel actuator to apply a third feedback torque to the steering wheel based on the steering wheel angle, the torque applied by the user, and the corrected target steering wheel angle.

[0132] Example 19 includes the method according to Example 18, wherein after the third feedback torque is applied, if the user-applied torque is released, the method further includes causing the steering wheel actuator to apply a fourth feedback torque to the steering wheel for a time interval.

[0133] Example 20 includes the method according to any one or more of Examples 18 to 19, wherein the corrected target steering wheel angle is calculated based on the target steering wheel angle and the difference between the user-applied torque and the maximum feedback torque.

Claims

1. A steer-by-wire (SBW) system for vehicles, comprising: steering wheel; A steering wheel actuator coupled to the steering wheel; A road wheel actuator, the road wheel actuator being coupled to the road wheel of the vehicle; Machine-readable instructions; as well as Control device, the control device being configured to execute the machine-readable instructions in order to: Determine the steering wheel angle; The steering wheel actuator applies a first feedback torque to the steering wheel based on the steering wheel angle and the target steering wheel angle; Based on a user-applied torque greater than the first feedback torque, the steering wheel actuator applies a second feedback torque to the steering wheel based on the steering wheel angle, the target steering wheel angle, and the user-applied torque. as well as The road wheel actuators steer the vehicle based on the steering wheel angle.

2. The SBW steering system of claim 1, wherein if the torque applied by the user is greater than the maximum feedback torque of the steering wheel actuator, the control device causes the steering wheel actuator to apply a third feedback torque to the steering wheel based on the steering wheel angle, the torque applied by the user, and the corrected target steering wheel angle.

3. The SBW steering system of claim 2, wherein after the third feedback torque is applied, if the user-applied torque is released, the control device causes the steering wheel actuator to apply a fourth feedback torque to the steering wheel for a time interval.

4. The SBW steering system of claim 2, wherein the corrected target steering wheel angle is calculated based on the target steering wheel angle and the difference between the user-applied torque and the maximum feedback torque.

5. The SBW steering system of claim 2, wherein the corrected target steering wheel angle is proportional to the difference between the user-applied torque and the maximum feedback torque.

6. The SBW steering system of claim 1, wherein the target steering wheel angle is based on the vehicle's predetermined destination.

7. The SBW steering system of claim 1, wherein the target steering wheel angle is based on the autonomous driving function of the vehicle.

8. The SBW steering system of claim 1, wherein the target steering wheel angle is based at least on a lookup table.

9. A non-transitory computer-readable medium comprising instructions for causing a programmable circuit system to perform at least the following operations: Determine the steering wheel angle of the vehicle; The vehicle's steering wheel actuator applies a first feedback torque to the steering wheel based on the steering wheel angle and the target steering wheel angle; Based on a user-applied torque greater than the first feedback torque, the steering wheel actuator applies a second feedback torque to the steering wheel based on the steering wheel angle, the target steering wheel angle, and the user-applied torque. as well as The vehicle's road wheel actuators steer the vehicle based on the steering wheel angle.

10. The non-transitory computer-readable medium of claim 9, wherein if the user-applied torque is greater than the maximum feedback torque of the steering wheel actuator, the programmable circuitry causes the steering wheel actuator to apply a third feedback torque to the steering wheel based on the steering wheel angle, the user-applied torque, and the corrected target steering wheel angle.

11. The non-transitory computer-readable medium of claim 10, wherein after the third feedback torque is applied, if the user-applied torque is released, the programmable circuitry causes the steering wheel actuator to apply a fourth feedback torque to the steering wheel for a time interval.

12. The non-transitory computer-readable medium of claim 10, wherein the corrected target steering wheel angle is calculated based on the target steering wheel angle and the difference between the user-applied torque and the maximum feedback torque.

13. The non-transitory computer-readable medium of claim 10, wherein the corrected target steering wheel angle is proportional to the difference between the user-applied torque and the maximum feedback torque.

14. The non-transitory computer-readable medium of claim 9, wherein the target steering wheel angle is based on a predetermined destination of the vehicle.

15. The non-transitory computer-readable medium of claim 9, wherein the target steering wheel angle is based on the autonomous driving function of the vehicle.

16. The non-transitory computer-readable medium of claim 9, wherein the target steering wheel angle is based at least on a lookup table.

17. A method for operating a steer-by-wire system, i.e., a SBW steering system, comprising: Determine the steering wheel angle of the vehicle; The vehicle's steering wheel actuator applies a first feedback torque to the steering wheel based on the steering wheel angle and the target steering wheel angle; Based on a user-applied torque greater than the first feedback torque, the steering wheel actuator applies a second feedback torque to the steering wheel based on the steering wheel angle, the target steering wheel angle, and the user-applied torque. as well as The vehicle's road wheel actuators steer the vehicle based on the steering wheel angle.

18. The method of claim 17, wherein if the user-applied torque is greater than the maximum feedback torque of the steering wheel actuator, the method further comprises causing the steering wheel actuator to apply a third feedback torque to the steering wheel based on the steering wheel angle, the user-applied torque, and the corrected target steering wheel angle.

19. The method of claim 18, wherein after the third feedback torque is applied, if the user-applied torque is released, the method further comprises causing the steering wheel actuator to apply a fourth feedback torque to the steering wheel for a time interval.

20. The method of claim 18, wherein the corrected target steering wheel angle is calculated based on the target steering wheel angle and the difference between the user-applied torque and the maximum feedback torque.

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