System and method for controlling speed of steering wheel returning to center

Abstract

An apparatus for control of steering wheel return to a center is configured to: determine a desired speed value based on a vehicle speed value and a steering wheel position value; determining a control speed mix value based on the vehicle speed value and a driver applied steering wheel torque value; determining a final desired speed value based on the desired speed value and the control speed mix value; determining a proportional-integral control value based on the control speed mix value and an error value associated with the final desired speed value; determining a static return command value based on the steering wheel position value and the vehicle speed value; determining a hybrid command value based on the proportional-integral control value and the static return command value; and selectively controlling a steering wheel of the vehicle to return to a center based on the mix command value.

Description

Technical Field

[0001] The present disclosure relates to vehicle steering, and in particular to systems and methods for controlling the speed at which a steering wheel returns to center. Background Art

[0002] Vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transportation) typically include various systems, such as a steering system (which may include an electronic power steering (EPS) system, a steer-by-wire (SbW) steering system, a hydraulic steering system, or other suitable steering system) and / or other suitable systems (e.g., such as a braking system, a propulsion system, etc.). Such systems of a vehicle typically control various aspects of vehicle steering (e.g., including providing steering assistance to an operator of the vehicle, controlling steerable wheels of the vehicle, etc.), vehicle propulsion, vehicle braking, etc. Summary of the invention

[0003] The present disclosure generally relates to steering systems.

[0004] One aspect of the disclosed embodiment includes a method for control of steering wheel return to center. The method includes: receiving a vehicle speed value indicating a speed of a vehicle; receiving a steering wheel position value indicating a position of a steering wheel of a vehicle; receiving a steering wheel speed value indicating a speed of a steering wheel of a vehicle; and receiving a driver-applied steering wheel torque value, the driver-applied steering wheel torque value indicating an amount of torque applied to a steering wheel by a driver of the vehicle. The method also includes: determining a desired speed value based on the vehicle speed value and the steering wheel position value; determining a control speed blend value based on the vehicle speed value and the driver-applied steering wheel torque value; and determining a final desired speed value based on the desired speed value and the control speed blend value. The method also includes: determining an error value based on the final desired speed value and the steering wheel speed value; determining a proportional-integral control value based on the control speed blend value and the error value; and determining a static return command value based on the steering wheel position value and the vehicle speed value. The method also includes: determining a blend command value based on the proportional-integral control value and the static return command value; and selectively controlling the steering wheel of the vehicle to return to center based on the blend command value.

[0005] Another aspect of the disclosed embodiment includes a system for controlling a steering wheel return to center. The system includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: receive a vehicle speed value indicating a speed of a vehicle; receive a steering wheel position value indicating a position of a steering wheel of a vehicle; receive a steering wheel speed value indicating a speed of a steering wheel of a vehicle; receive a driver-applied steering wheel torque value indicating an amount of torque applied to a steering wheel by a driver of the vehicle; determine a desired speed value based on the vehicle speed value and the steering wheel position value; determine a control speed blend value based on the vehicle speed value and the driver-applied steering wheel torque value; determine a final desired speed value based on the desired speed value and the control speed blend value; determine an error value based on the final desired speed value and the steering wheel speed value; determine a proportional-integral control value based on the control speed blend value and the error value; determine a static return command value based on the steering wheel position value and the vehicle speed value; determine a blended command value based on the proportional-integral control value and the static return command value; and selectively control the steering wheel of the vehicle to return to center based on the blended command value.

[0006] Another aspect of the disclosed embodiment includes a device for controlling a steering wheel return to center. The device includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: determine a desired speed value based on a vehicle speed value indicating a speed of the vehicle and a steering wheel position value indicating a position of a steering wheel of the vehicle; determine a control speed blend value based on the vehicle speed value and a driver-applied steering wheel torque value, the driver-applied steering wheel torque value indicating the amount of torque applied to the steering wheel by the driver of the vehicle; determine a final desired speed value based on the desired speed value and the control speed blend value; determine a proportional-integral control value based on the control speed blend value and an error value associated with the final desired speed value; determine a static return command value based on the steering wheel position value and the vehicle speed value; determine a blended command value based on the proportional-integral control value and the static return command value; and selectively control the steering wheel of the vehicle to return to center based on the blended command value.

[0007] These and other aspects of the disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is best understood through the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not drawn to scale. Instead, the sizes of the various features are arbitrarily enlarged or reduced for clarity.

[0009] Figure 1A vehicle in accordance with the principles of the present disclosure is generally shown.

[0010] Figure 2 A controller according to the principles of the present disclosure is generally shown.

[0011] Figure 3 A block diagram of a controlled speed return technique in accordance with the principles of the present disclosure is generally shown.

[0012] Figure 4 A block diagram of a target speed technique in accordance with the principles of the present disclosure is generally shown.

[0013] Figure 5 A block diagram generally illustrates a static return command technique in accordance with the principles of the present disclosure.

[0014] Figure 6 A block diagram generally illustrates a hybrid technique in accordance with the principles of the present disclosure.

[0015] Figure 7 is a flow chart generally illustrating a steering wheel return to center control method according to the principles of the present disclosure. DETAILED DESCRIPTION

[0016] The following discussion is directed to various embodiments of the present disclosure. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used as limiting the scope of the present disclosure, including the claims. In addition, it will be understood by those skilled in the art that the following description has a wide range of applications, and the discussion of any embodiment is intended only to be an exemplary discussion of that embodiment, and is not intended to imply that the scope of the present disclosure, including the claims, is limited to that embodiment.

[0017] As described above, vehicles (such as automobiles, trucks, SUVs, crossovers, minivans, boats, airplanes, ATVs, recreational vehicles, or other suitable forms of transportation) typically include various systems, such as a steering system (which may include an EPS steering system, an SbW steering system, a hydraulic steering system, or other suitable steering systems) and / or other suitable systems (e.g., such as a braking system, a propulsion system, etc.). Such systems of a vehicle typically control various aspects of vehicle steering (e.g., including providing steering assistance to an operator of the vehicle, controlling steerable wheels of the vehicle, etc.), vehicle propulsion, vehicle braking, etc.

[0018] Typically, advanced steering systems allow for the incorporation of advanced algorithms that provide a torque signal that is added to the typical assist torque. A common advanced function implemented is a return to center function. In applications where the restoring force of the vehicle's tires is insufficient to overcome the friction level in the steering system, such a return to center function provides an additional torque to return the vehicle's steering wheel to the center. For example, the return to center function may include a two-dimensional (2D) lookup table with inputs including vehicle speed and steering wheel angle to determine a return torque that is added to the normal steering torque. However, changes in operating conditions and changes in friction levels can change the speed at which the steering wheel returns to the center, resulting in the steering wheel returning too quickly or too slowly.

[0019] To overcome these shortcomings, advanced steering systems may employ a controlled speed return to center function. Typically, the controlled speed return to center function may include a target speed block, a proportional block, a proportional integral (PI) control block, and a limit block. The controlled speed return to center function receives signals from various controllers, from vehicle serial communications, and / or from sensors in the system. Additionally, filters may be applied to various signals, including driver torque signals and torsion bar (T-bar) torque signals.

[0020] Typically, the target speed block includes a 2D lookup table that uses the absolute values ​​of the vehicle speed and steering wheel position input signals to calculate a desired speed magnitude. The desired speed magnitude may have a value greater than 0 degrees per second (deg / sec) away from the center and may decrease to 0 deg / sec at or near a 0 degree steering wheel angle.

[0021] The target speed block may also include a 2D lookup table that uses the absolute values ​​of the vehicle speed and driver torque input signals to calculate a desired speed scaling factor having a value between 0 and 1 (e.g., where the desired speed scaling factor value is typically relatively close to 1 when the driver torque value approaches 0 Newton-meters (Nm), and the desired speed scaling factor value will decrease to 0 as the driver torque value increases).

[0022] The final desired speed signal is determined by multiplying the desired speed ratio and the desired speed magnitude together with a term equal to the sign of the steering wheel position signal times negative one (-1). A third term may be used to provide a desired speed toward the center position.

[0023] The proportional block may include multiple blocks that calculate various proportional factors from 0 to 1 based on various input signals. For example, a T-bar torque proportional factor is calculated using a 2D lookup table that uses the absolute value of the vehicle speed and T-bar torque input signals to calculate a proportional factor with a value between 0 and 1. All of the various proportional factors are multiplied to produce the final control proportional factor value. The speed error signal is determined by subtracting the desired speed from the measured steering wheel speed. This signal is provided to the PI control block together with the control proportional factor signal. The PI control block multiplies the control proportional factor by the speed error signal and uses a PI controller to reduce the speed error. The output of the PI control block is provided to a limit block that limits the final return command to within the desired range.

[0024] Such controlled speed return functions may have inherent disadvantages. For example, the return function may transition between a condition where the driver allows the steering system to return to center and a condition where the driver actively steers the vehicle. The desired speed proportional factor is a function used to manage this transition. When the driver allows the steering system to return to center, the desired speed proportional factor produces a desired speed value equal to or close to the value determined from the desired speed lookup table, while for a condition where the driver actively steers the vehicle, the desired speed proportional factor produces a value equal to or close to 0. When the driver actively steers the vehicle, a speed of 0 is only desired for a limited number of conditions. This can result in a large speed error signal value provided to the PI control block.

[0025] In addition, a second function for managing the transition is a control scale factor. This function has the effect of turning off the return function when the control scale factor is 0. The determination of the control scale factor has multiple lookup tables with different input signals to take into account different conditions when the return function is to be turned off. When the friction level in the steering system requires a high return torque, it is generally desired to have a nominal return torque even when the driver is actively steering. When the return function transitions between a condition in which the driver allows the steering system to return to center and a condition in which the driver actively steers the vehicle, setting the control scale factor to 0 may result in a less than desired return torque value and / or may result in a relatively large change in the return torque. These disadvantages may result in a degraded steering feel while being difficult to adjust.

[0026] Therefore, systems and methods configured to provide improved control of the speed of steering wheel return to center (such as those described herein) may be desirable. In some embodiments, the systems and methods described herein may be configured to provide a controlled speed return function that includes functionality for providing a return command for two conditions: (i) a condition in which the driver allows the system to return to center; and (ii) a condition in which the driver actively steers. The systems and methods described herein may be configured to transition between the two conditions.

[0027] The systems and methods described herein may be configured to determine a target speed in response to a condition in which the driver allows the system to return to center.The systems and methods described herein may be configured to use PI control techniques to reduce the error between the desired speed and the measured speed.

[0028] The systems and methods described herein may be configured to determine the desired speed as the actual steering wheel speed in response to a condition where the driver is actively steering. Additionally or alternatively, the systems and methods described herein may be configured to provide a static return torque. The systems and methods described herein may be configured to use a hybrid function to transition between two conditions. The systems and methods described herein may be configured to improve steering feel and improve system adjustment capabilities.

[0029] In some embodiments, the systems and methods described herein may be configured to provide a steering wheel return to center control. The systems and methods described herein may be configured to receive a vehicle speed value indicating the speed of the vehicle. The systems and methods described herein may be configured to receive a steering wheel position value indicating the position of the steering wheel of the vehicle. The systems and methods described herein may be configured to receive a steering wheel speed value indicating the speed of the steering wheel of the vehicle. The systems and methods described herein may be configured to receive a driver-applied steering wheel torque value indicating the amount of torque applied to the steering wheel by the driver of the vehicle.

[0030] The systems and methods described herein may be configured to determine a desired speed value based on a vehicle speed value and a steering wheel position value.

[0031] The systems and methods described herein may be configured to determine a control speed blend value based on a vehicle speed value and a driver-applied steering wheel torque value.

[0032] The systems and methods described herein may be configured to determine a final desired speed value based on the desired speed value and the control speed blend value. For example, the systems and methods described herein may be configured to determine the final desired speed value by adding the result of multiplying the desired speed value by the control speed blend signal and the result of one minus the control speed blend value multiplied by the steering wheel speed value. The final desired speed value may correspond to a return to center condition in which the driver of the vehicle allows the steering wheel to return to the center position without engaging the steering wheel.

[0033] The systems and methods described herein may be configured to determine an error value based on a final desired speed value and a steering wheel speed value. For example, the systems and methods described herein may be configured to determine an error value by subtracting the final desired speed value from the steering wheel speed value.

[0034] The systems and methods described herein may be configured to determine the PI control value based on the control speed blend value and the error value. For example, the systems and methods described herein may be configured to determine the PI control value by multiplying the control speed blend value by the error value.

[0035] The systems and methods described herein may be configured to determine a static return command value based on a steering wheel position value and a vehicle speed value. The static return command value may correspond to a return to center condition where the driver is actively steering the vehicle using the steering wheel.

[0036] The systems and methods described herein may be configured to determine a hybrid command value based on a proportional-integral control value and a static return command value.

[0037] The systems and methods described herein may be configured to selectively control the steering wheel of a vehicle to return to center based on a hybrid command value. For example, the systems and methods described herein may be configured to selectively control the steering wheel of a vehicle to return to center by limiting the hybrid command value based on a final desired speed value.

[0038] Figure 1 A vehicle 10 in accordance with the principles of the present disclosure is generally shown. The vehicle 10 may include any suitable vehicle, such as a car, a truck, a sport utility vehicle, a minivan, a crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although the vehicle 10 is illustrated as a passenger vehicle having wheels and used on a road, the principles of the present disclosure may be applied to other vehicles, such as airplanes, ships, trains, drones, or other suitable vehicles.

[0039] The vehicle 10 includes a body 12 and a hood 14. A passenger compartment 18 is at least partially defined by the body 12. Another portion of the body 12 defines an engine compartment 20. The hood 14 is movably attached to a portion of the body 12 such that when the hood 14 is in a first or open position, the hood 14 provides access to the engine compartment 20, and when the hood 14 is in a second or closed position, the hood 14 covers the engine compartment 20. In some embodiments, the engine compartment 20 may be disposed at the rear of the vehicle 10 (compared to what is generally shown).

[0040] The passenger compartment 18 may be disposed rearward of the engine compartment 20, but in embodiments where the engine compartment 20 is disposed at the rear of the vehicle 10, the passenger compartment 18 may be disposed forward of the engine compartment 20. The vehicle 10 may include any suitable propulsion system, including: an internal combustion engine; one or more electric motors (e.g., an electric vehicle); one or more fuel cells; a hybrid (e.g., a hybrid vehicle) propulsion system including a combination of an internal combustion engine, one or more electric motors; and / or any other suitable propulsion system.

[0041] In some embodiments, the vehicle 10 may include a gasoline engine or a gasoline fuel engine, such as a spark ignition engine. In some embodiments, the vehicle 10 may include a diesel fuel engine, such as a compression ignition engine. The engine compartment 20 accommodates and / or surrounds at least some components of the propulsion system of the vehicle 10. Additionally or alternatively, a propulsion control device (e.g., an accelerator actuator (e.g., an accelerator pedal), a brake actuator (e.g., a brake pedal), a steering wheel, and other such components) are disposed in the passenger compartment 18 of the vehicle 10. The propulsion control device may be actuated or controlled by an operator of the vehicle 10 and may be directly connected to corresponding components of the propulsion system, such as a throttle, brake, axle, vehicle transmission, etc., respectively. In some embodiments, the propulsion control device may transmit a signal to a vehicle computer (e.g., drive-by-wire), which in turn may control corresponding propulsion components of the propulsion system. Thus, in some embodiments, the vehicle 10 may be an autonomous vehicle.

[0042] In some embodiments, the vehicle 10 includes a transmission that is connected to the crankshaft via a flywheel or a clutch or a fluid coupling. In some embodiments, the transmission includes a manual transmission. In some embodiments, the transmission includes an automatic transmission. In the case of an internal combustion engine or a hybrid vehicle, the vehicle 10 may include one or more pistons that operate in conjunction with the crankshaft to generate force that is transmitted to one or more axles through the transmission, which causes the wheels 22 to rotate. When the vehicle 10 includes one or more electric motors, the vehicle battery and / or fuel cell provides energy to the electric motors to rotate the wheels 22.

[0043] The vehicle 10 may include an automatic vehicle propulsion system, such as cruise control, adaptive cruise control, automatic braking control, other automatic vehicle propulsion systems, or combinations thereof. The vehicle 10 may be an autonomous or semi-autonomous vehicle, or another suitable type of vehicle. The vehicle 10 may include additional features or fewer features than those generally shown and / or disclosed herein.

[0044] In some embodiments, the vehicle 10 may include an Ethernet component 24, a controller area network (CAN) bus 26, a media oriented system transport component (MOST) 28, a FlexRay component 30 (e.g., a wire control system, etc.), and a local interconnect network component (LIN) 32. The vehicle 10 may use the CAN bus 26, the MOST 28, the FlexRay component 30, the LIN 32, other suitable networks or communication systems, or a combination thereof, to communicate various information from sensors, such as within or outside the vehicle, to various processors or controllers, such as within or outside the vehicle. The vehicle 10 may include additional features or fewer features than those generally shown and / or disclosed herein.

[0045] In some embodiments, the vehicle 10 may include a steering system, such as an EPS system, a steer-by-wire steering system (e.g., which may include or be in communication with one or more controllers that control components of the steering system without using a mechanical connection between a steering wheel of the vehicle 10 and the wheels 22), a hydraulic steering system (e.g., which may include a magnetic actuator incorporated into a valve assembly of the hydraulic steering system), or other suitable steering systems.

[0046] The steering system may include an open-loop feedback control system or mechanism, a closed-loop feedback control system or mechanism, or a combination thereof. The steering system may be configured to receive various inputs, including but not limited to: steering wheel position, input torque, one or more wheel positions, other suitable inputs or information, or a combination thereof.

[0047] Additionally or alternatively, the input may include steering wheel torque, steering wheel angle, motor speed, vehicle speed, estimated motor torque command, other suitable input, or a combination thereof. The steering system may be configured to provide steering functionality and / or control to the vehicle 10. For example, the steering system may generate an assist torque based on various inputs. The steering system may be configured to selectively control the motor of the steering system using the assist torque to provide steering assistance to the operator of the vehicle 10.

[0048] In some embodiments, the vehicle 10 may include a controller, such as controller 100. Figure 2. The controller 100 may include any suitable controller, such as an electronic control unit or other suitable controller. For example, the controller 100 may be configured to control various functions of the steering system and / or various functions of the vehicle 10. The controller 100 may include a processor 102 and a memory 104. The processor 102 may include any suitable processor, such as those described herein. Additionally or alternatively, in addition to the processor 102 or in addition to the processor 102, the controller 100 may include any suitable number of processors. The memory 104 may include a single disk or multiple disks (e.g., a hard disk drive), and include a storage management module that manages one or more partitions within the memory 104. In some embodiments, the memory 104 may include flash memory, semiconductor (solid-state) memory, etc. The memory 104 may include a random access memory (RAM), a read-only memory (ROM), or a combination thereof. The memory 104 may include instructions that, when executed by the processor 102, cause the processor 102 to at least control various aspects of the vehicle 10.

[0049] The controller 100 may receive one or more signals from various measuring devices or sensors 106, which indicate sensed or measured characteristics of the vehicle 10. The sensor 106 may include any suitable sensor, measuring device, and / or other suitable mechanism. For example, the sensor 106 may include one or more torque sensors or devices, one or more steering wheel position sensors or devices, one or more motor position sensors or devices, one or more position sensors or devices, one or more radar sensors or devices, one or more lidar sensors or devices, one or more sonar sensors or devices, one or more image capture sensors or devices, other suitable sensors or devices, or a combination thereof. The one or more signals may indicate steering wheel torque, steering wheel angle, motor speed, vehicle speed, other suitable information, or a combination thereof.

[0050] In some embodiments, the controller 100 may be configured to provide a steering wheel return to center control. For example, the controller 100 may determine a return command for a condition when the driver allows the steering system of the vehicle 10 to return to center. The controller 100 may determine a return command when the driver actively steers the vehicle 10. The controller 100 may transition from one condition to another.

[0051] Figure 3A block diagram of a controlled speed return function 200 is generally shown. The controller 100 may be configured to use the processor 102 or other suitable processor to execute instructions stored on the memory 104 or other suitable memory to perform the function 200. For example, the controller 100 may receive various signals from the sensor 106 or from any suitable source. The controller 100 may apply filters to the signals, such as the filter shown on the driver torque signal.

[0052] Function 200 may include a target speed block 202 (e.g., substantially Figure 3 and Figure 4 ), PI control block 204, static return command block 206 (e.g., generally in Figure 3 and Figure 5 ), a mixing function block 208 (eg, generally in Figure 3 and Figure 6 ) and a limiting block 210.

[0053] Using the target speed block 202, the controller 100 can provide a desired speed signal and a control speed blend signal. The target speed block 202 can include a 2D lookup table that uses the absolute value of the vehicle speed and steering wheel position input signals to calculate a desired speed magnitude. The desired speed magnitude can have a value greater than 0 deg / sec when away from the center and decrease to 0 deg / sec at or substantially at a 0 degree steering wheel angle. The controller 100 can multiply the desired speed magnitude by a term equal to the sign of the steering wheel position signal multiplied by -1, which can provide a desired speed toward the center position.

[0054] Using the target speed block 202, the controller 100 may use the absolute value of the vehicle speed and the driver torque input signal to calculate a controlled speed blending signal having a controlled speed blending factor value, which may have a value limited between 0 and 1. When the driver torque value is equal to or substantially equal to 0 Nm, the controlled speed blending factor value may be equal to or substantially equal to 1, and when the driver torque value increases, the controlled speed blending factor value may decrease to 0.

[0055] The controller 100 may use a lookup table to calculate a desired speed that represents the desired speed for conditions when the driver allows the steering system to return to center. The desired speed for conditions when the driver is actively steering may correspond to the measured steering wheel speed (e.g., it may provide a speed error signal of 0 for all conditions when the driver is actively steering).

[0056] In some embodiments, the controller 100 may use a control speed blend signal to transition between these two conditions. The controller 100 may determine the final desired speed signal by multiplying the desired speed calculated from the lookup table with the control speed blend signal, multiplying one minus the control speed blend signal with the measured steering wheel speed signal, and adding the two results. The controller 100 may apply a filter to the final desired speed signal.

[0057] In some embodiments, the controller 100 may determine a speed error signal by subtracting the desired speed from the measured steering wheel speed. The controller 100 may provide the speed error signal and the control speed blend signal to the PI control block 204 .

[0058] Using the PI control block 204 , the controller 100 may multiply the control speed blend signal by the speed error signal to reduce the speed error. The controller 100 may provide the output of the PI control block 204 to a blending function block 208 .

[0059] In some embodiments, using the static return command block 206, the controller 100 can provide a return torque for the condition when the driver actively steers the vehicle 10. The controller 100 can use the lookup table of the static return command block 206 to calculate the return torque magnitude, which uses the absolute value of the steering wheel position input signal. The controller 100 can use the lookup table of the static return command block 206 to calculate the scale factor, which uses the vehicle speed input signal. The scale factor can be limited to a value between 0 and 1. The controller 100 can determine the final static return command by multiplying the return torque magnitude, the scale factor, and the term equal to the sign of the steering wheel position. Additionally or alternatively, the controller 100 can calculate the static return command by replacing two separate lookup tables with a single 2D lookup table in which the absolute value of the vehicle speed and the steering wheel position signal are input.

[0060] The controller 100 may receive the PI term from the output of the PI control block 204 and the static return command from the static return block 206 at the blending function block 208. Using the blending function block 208, the controller 100 calculates the blended return command by subtracting the control speed blended signal by one and multiplying the static return command signal and adding the result to the PI term. The controller 100 may provide the output of the blending function block 208 to a limiting block 210, which the controller 100 may use to limit the final return command to a desired range.

[0061] In some embodiments, the controller 100 may receive a vehicle speed value indicating the speed of the vehicle 10 from one or more of the sensors 106 or other suitable sources. The controller 100 may receive a steering wheel position value indicating the position of a steering wheel of the vehicle 10 from one or more of the sensors 106 or other suitable sources. The controller 100 may receive a steering wheel speed value indicating the speed of the steering wheel of the vehicle 10 from one or more of the sensors 106 or other suitable sources. The controller 100 may receive a driver-applied steering wheel torque value indicating the amount of torque applied to the steering wheel by the driver of the vehicle 10 from one or more of the sensors 106 or other suitable sources.

[0062] The controller 100 may determine the desired speed value based on the vehicle speed value and the steering wheel position value. The controller 100 may determine the control speed blend value based on the vehicle speed value and the steering wheel torque value applied by the driver. The controller 100 may determine the final desired speed value based on the desired speed value and the control speed blend value. For example, the controller 100 may determine the final desired speed value by adding the result of multiplying the desired speed value by the control speed blend signal and the result of subtracting the control speed blend value and then multiplying by the steering wheel speed value. The final desired speed value may correspond to a return to center condition in which the driver of the vehicle 10 allows the steering wheel to return to the center position without engaging the steering wheel.

[0063] The controller 100 may determine the error value based on the final desired speed value and the steering wheel speed value. For example, the controller 100 may determine the error value by subtracting the final desired speed value from the steering wheel speed value.

[0064] The controller 100 may determine the PI control value based on the control speed blend value and the error value. For example, the controller 100 may determine the PI control value by multiplying the control speed blend value by the error value.

[0065] The controller 100 may determine a static return command value based on the steering wheel position value and the vehicle speed value. The static return command value may correspond to a return to center condition where the driver is actively steering the vehicle using the steering wheel. The controller 100 may determine a hybrid command value based on the proportional-integral control value and the static return command value.

[0066] The controller 100 may selectively control the steering wheel of the vehicle 10 to return to the center based on the hybrid command value. For example, the controller 100 may selectively control the steering wheel of the vehicle to return to the center by limiting the hybrid command value based on the final desired speed value.

[0067] In some embodiments, the controller 100 can perform the methods described herein. However, the methods described herein performed by the controller 100 are not meant to be limiting, and any type of software executed on a controller or processor can perform the methods described herein without departing from the scope of the present disclosure. For example, a controller (such as a processor executing software within a computing device) can perform the methods described herein.

[0068] Figure 7 1 is a flow chart generally illustrating a steering wheel return to center control method 300 according to the principles of the present disclosure. At 302, the method 300 receives a vehicle speed value indicating a speed of a vehicle. For example, the controller 100 may receive a vehicle speed value indicating a speed of the vehicle 10.

[0069] At 304 , the method 300 receives a steering wheel position value indicating a position of a steering wheel of the vehicle. For example, the controller 100 may receive a steering wheel position value indicating a position of a steering wheel of the vehicle 10 .

[0070] At 306 , the method 300 receives a steering wheel speed value indicative of a speed of a steering wheel of the vehicle. For example, the controller 100 may receive a steering wheel speed value indicative of a speed of a steering wheel of the vehicle 10 .

[0071] At 308, the method 300 receives a driver applied steering wheel torque value indicating an amount of torque applied to the steering wheel by the driver of the vehicle. For example, the controller 100 may receive a driver applied steering wheel torque value indicating an amount of torque applied to the steering wheel by the driver of the vehicle 10.

[0072] At 310 , the method 300 determines a desired speed value based on the vehicle speed value and the steering wheel position value. For example, the controller 100 may determine the desired speed value based on the vehicle speed and the steering wheel position value.

[0073] At 312 , the method 300 determines a control speed blend value based on the vehicle speed value and the driver-applied steering wheel torque value. For example, the controller 100 may determine the control speed blend value based on the vehicle speed value and the driver-applied steering wheel torque value.

[0074] At 314 , the method 300 determines a final desired speed value based on the desired speed value and the control speed blend value. For example, the controller 100 may determine the final desired speed value based on the desired speed value and the control speed blend value.

[0075] At 316 , method 300 determines an error value based on the final desired speed value and the steering wheel speed value. For example, controller 100 may determine the error value based on the final desired speed value and the steering wheel speed value.

[0076] At 318 , the method 300 determines a PI control value based on the control speed blend value and the error value. For example, the controller 100 may determine the PI control value based on the control speed blend value and the error value.

[0077] At 320 , method 300 determines a static return command value based on the steering wheel position value and the vehicle speed value. For example, controller 100 may determine the static return command value based on the steering wheel position value and the vehicle speed value.

[0078] At 322 , the method 300 determines a hybrid command value based on the PI control value and the static return command value. For example, the controller 100 may determine the hybrid command value based on the PI control value and the static return command value.

[0079] At 324 , the method 300 selectively controls the steering wheel of the vehicle to return to the center based on the hybrid command value. For example, the controller 100 may selectively control the steering wheel of the vehicle to return to the center based on the hybrid command value.

[0080] In some embodiments, a method for controlling a steering wheel return to center includes: receiving a vehicle speed value indicating a speed of a vehicle; receiving a steering wheel position value indicating a position of a steering wheel of the vehicle; receiving a steering wheel speed value indicating a speed of a steering wheel of the vehicle; and receiving a driver-applied steering wheel torque value, the driver-applied steering wheel torque value indicating an amount of torque applied to the steering wheel by a driver of the vehicle. The method further includes: determining a desired speed value based on the vehicle speed value and the steering wheel position value; determining a control speed blend value based on the vehicle speed value and the driver-applied steering wheel torque value; and determining a final desired speed value based on the desired speed value and the control speed blend value. The method further includes: determining an error value based on the final desired speed value and the steering wheel speed value; determining a proportional-integral control value based on the control speed blend value and the error value; and determining a static return command value based on the steering wheel position value and the vehicle speed value. The method further includes: determining a blend command value based on the proportional-integral control value and the static return command value; and selectively controlling the steering wheel of the vehicle to return to center based on the blend command value.

[0081] In some embodiments, the final desired speed value corresponds to a return to center condition in which the driver of the vehicle allows the steering wheel to return to the center position without engaging the steering wheel. In some embodiments, the static return command value corresponds to a return to center condition in which the driver uses the steering wheel to actively steer the vehicle. In some embodiments, determining the final desired speed value based on the desired speed value and the control speed blend value includes multiplying the desired speed value by a control speed blend signal. In some embodiments, determining the final desired speed value based on the desired speed value and the control speed blend value also includes determining the final desired speed value by adding the result of multiplying the desired speed value by the control speed blend value and one minus the control speed blend value multiplied by the steering wheel speed value. In some embodiments, determining the error value based on the final desired speed value and the steering wheel speed value includes subtracting the final desired speed value from the steering wheel speed value. In some embodiments, determining the proportional integral control value based on the control speed blend value and the error value includes multiplying the control speed blend value by the error value. In some embodiments, selectively controlling the steering wheel of the vehicle to return to center based on the hybrid command value includes limiting the hybrid command value based on the final desired speed value. In some embodiments, the steering wheel is associated with a steer-by-wire steering system. In some embodiments, the steering wheel is associated with an electronic power steering system.

[0082] In some embodiments, a system for controlling a steering wheel return to center includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: receive a vehicle speed value indicating a speed of a vehicle; receive a steering wheel position value indicating a position of a steering wheel of the vehicle; receive a steering wheel speed value indicating a speed of a steering wheel of the vehicle; receive a driver-applied steering wheel torque value indicating an amount of torque applied to the steering wheel by a driver of the vehicle; determine a desired speed value based on the vehicle speed value and the steering wheel position value; determine a control speed blend value based on the vehicle speed value and the driver-applied steering wheel torque value; determine a final desired speed value based on the desired speed value and the control speed blend value; determine an error value based on the final desired speed value and the steering wheel speed value; determine a proportional-integral control value based on the control speed blend value and the error value; determine a static return command value based on the steering wheel position value and the vehicle speed value; determine a blended command value based on the proportional-integral control value and the static return command value; and selectively control the steering wheel of the vehicle to return to center based on the blended command value.

[0083] In some embodiments, the final desired speed value corresponds to a return to center condition in which the driver of the vehicle allows the steering wheel to return to the center position without engaging the steering wheel. In some embodiments, the static return command value corresponds to a return to center condition in which the driver uses the steering wheel to actively steer the vehicle. In some embodiments, the instruction further causes the processor to determine the final desired speed value based on the desired speed value and the control speed mixed value by adding the result of multiplying the desired speed value by the control speed mixed signal and the result of subtracting the control speed mixed value and multiplying the steering wheel speed value. In some embodiments, the instruction further causes the processor to determine the error value based on the final desired speed value and the steering wheel speed value by subtracting the final desired speed value from the steering wheel speed value. In some embodiments, the instruction further causes the processor to determine the proportional integral control value based on the control speed mixed value and the error value by multiplying the control speed mixed value by the error value. In some embodiments, the instruction further causes the processor to selectively control the steering wheel of the vehicle to return to the center based on the mixed command value by limiting the mixed command value based on the final desired speed value. In some embodiments, the steering wheel is associated with a steer-by-wire steering system. In some embodiments, the steering wheel is associated with an electronic power steering system.

[0084] In some embodiments, a device for controlling a steering wheel to return to center includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: determine a desired speed value based on a vehicle speed value indicating a speed of a vehicle and a steering wheel position value indicating a position of a steering wheel of the vehicle; determine a control speed blend value based on the vehicle speed value and a driver-applied steering wheel torque value, the driver-applied steering wheel torque value indicating the amount of torque applied to the steering wheel by a driver of the vehicle; determine a final desired speed value based on the desired speed value and the control speed blend value; determine a proportional-integral control value based on the control speed blend value and an error value associated with the final desired speed value; determine a static return command value based on the steering wheel position value and the vehicle speed value; determine a blended command value based on the proportional-integral control value and the static return command value; and selectively control the steering wheel of the vehicle to return to center based on the blended command value.

[0085] The above discussion is intended to illustrate the principles and various embodiments of the present disclosure. Once the above disclosure is fully understood, many changes and modifications will become apparent to those skilled in the art. It is intended that the appended claims be interpreted as covering all such changes and modifications.

[0086] The word "example" is used herein to mean used as an example, instance or illustration. Any aspect or design described herein as an "example" is not necessarily to be interpreted as being more preferred or advantageous than other aspects or designs. On the contrary, the use of the word "example" is intended to present the concept in a specific way. As used in this application, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clearly seen from the context, "X includes A or B" is intended to represent any natural inclusive arrangement. That is, if X includes A; X includes B; or X includes both A and B, then "X includes A or B" is satisfied in any of the foregoing cases. In addition, the article "a / an" used in this application and the appended claims should generally be interpreted as meaning "one or more", unless otherwise specified or clearly pointed to the singular form from the context. In addition, unless so described, the use of the term "embodiment" or "one embodiment" throughout the text is not intended to represent the same embodiment or embodiment.

[0087] The implementation of the systems, algorithms, methods, instructions, etc. described herein may be implemented in hardware, software, or any combination thereof. Hardware may include, for example, a computer, an intellectual property (IP) core, an application specific integrated circuit (ASIC), a programmable logic array, an optical processor, a programmable logic controller, microcode, a microcontroller, a server, a microprocessor, a digital signal processor, or any other suitable circuit. In the claims, the term "processor" shall be understood to include any of the foregoing hardware, alone or in combination. The terms "signal" and "data" may be used interchangeably.

[0088] As used herein, the term module may include a packaged functional hardware unit designed to be used with other components, a set of instructions executable by a controller (e.g., a processor executing software or firmware), a processing circuit configured to perform a specific function, and a self-contained hardware or software component that interfaces with a larger system. For example, a module may include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an electrical circuit, a digital logic circuit, an analog circuit, a combination of discrete circuits, gate circuits and other types of hardware, or a combination thereof. In other embodiments, a module may include a memory that stores instructions executable by a controller to implement the features of the module.

[0089] Furthermore, in one aspect, for example, the systems described herein may be implemented using a general purpose computer or general purpose processor with a computer program that, when executed, implements any corresponding method, algorithm, and / or instruction described herein. Additionally or alternatively, for example, a special purpose computer / processor may be utilized that may include other hardware for implementing any method, algorithm, or instruction described herein.

[0090] In addition, all or part of the embodiments of the present disclosure may take the form of a computer program product that can be accessed from, for example, a computer-usable or computer-readable medium. A computer-usable or computer-readable medium can be, for example, any device that can tangibly contain, store, communicate, or transmit a program for use by or in conjunction with any processor. The medium can be, for example, an electronic, magnetic, optical, electromagnetic device, or a semiconductor device. Other suitable media may also be used.

[0091] The above embodiments, implementations and aspects have been described to allow easy understanding of the present disclosure and are not intended to limit the present disclosure. On the contrary, the present disclosure is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope should be given the broadest interpretation to cover all such modifications and equivalent structures permitted by law.

Claims

1. A method for controlling a steering wheel to return to center, the method comprising: receiving a vehicle speed value indicating a speed of the vehicle; receiving a steering wheel position value indicative of a position of a steering wheel of the vehicle; receiving a steering wheel speed value indicative of a speed of a steering wheel of the vehicle; receiving a driver applied steering wheel torque value indicating an amount of torque applied to the steering wheel by a driver of the vehicle; determining a desired speed value based on the vehicle speed value and the steering wheel position value; determining a control speed blend value based on the vehicle speed value and the driver applied steering wheel torque value; determining a final desired speed value based on the desired speed value and the control speed blend value; determining an error value based on the final desired speed value and the steering wheel speed value; determining a proportional-integral control value based on the control speed mixed value and the error value; determining a static return command value based on the steering wheel position value and the vehicle speed value; determining a hybrid command value based on the proportional-integral control value and the static return command value; as well as A steering wheel of the vehicle is selectively controlled to return to center based on the hybrid command value.

2. The method according to claim 1, wherein: The final desired speed value corresponds to a driver of the vehicle allowing the steering wheel to return to a center position without engaging a return to center condition of the steering wheel.

3. The method according to claim 1, wherein: The static return command value corresponds to a return to center condition where the driver is actively steering the vehicle using the steering wheel.

4. The method according to claim 1, wherein: Determining the final desired speed value based on the desired speed value and the control speed blend value includes multiplying the desired speed value by a control speed blend signal.

5. The method according to claim 4, wherein: Determining the final desired speed value based on the desired speed value and the control speed blend value further includes determining the final desired speed value by adding a result of multiplying the desired speed value by the control speed blend value and a result of one minus the control speed blend value multiplied by the steering wheel speed value.

6. The method according to claim 1, wherein: Determining the error value based on the final desired speed value and the steering wheel speed value includes subtracting the final desired speed value from the steering wheel speed value.

7. The method according to claim 1, wherein: Determining the proportional-integral control value based on the control speed blend value and the error value includes multiplying the control speed blend value by the error value.

8. The method according to claim 1, wherein: Selectively controlling a steering wheel of the vehicle to return to center based on the hybrid command value includes limiting the hybrid command value based on the final desired speed value.

9. The method according to claim 1, wherein: The steering wheel is associated with a steer-by-wire steering system.

10. The method according to claim 1, wherein: The steering wheel is associated with an electronic power steering system.

11. A system for controlling a steering wheel to return to center, the system comprising: processor; as well as a memory comprising instructions that, when executed by the processor, cause the processor to: receiving a vehicle speed value indicating a speed of the vehicle; receiving a steering wheel position value indicative of a position of a steering wheel of the vehicle; receiving a steering wheel speed value indicative of a speed of a steering wheel of the vehicle; receiving a driver applied steering wheel torque value indicating an amount of torque applied to the steering wheel by a driver of the vehicle; determining a desired speed value based on the vehicle speed value and the steering wheel position value; determining a control speed blend value based on the vehicle speed value and the driver applied steering wheel torque value; determining a final desired speed value based on the desired speed value and the control speed blend value; determining an error value based on the final desired speed value and the steering wheel speed value; determining a proportional-integral control value based on the control speed mixed value and the error value; determining a static return command value based on the steering wheel position value and the vehicle speed value; determining a hybrid command value based on the proportional-integral control value and the static return command value; as well as A steering wheel of the vehicle is selectively controlled to return to center based on the hybrid command value.

12. The system according to claim 11, wherein: The final desired speed value corresponds to a driver of the vehicle allowing the steering wheel to return to a center position without engaging a return to center condition of the steering wheel.

13. The system according to claim 11, wherein: The static return command value corresponds to a return to center condition where the driver is actively steering the vehicle using the steering wheel.

14. The system according to claim 11, wherein: The instructions further cause the processor to determine the final desired speed value based on the desired speed value and the control speed blend value by adding a result of multiplying the desired speed value by the control speed blend signal and a result of subtracting the control speed blend value by the steering wheel speed value.

15. The system according to claim 11, wherein: The instructions further cause the processor to determine the error value based on the final desired speed value and the steering wheel speed value by subtracting the final desired speed value from the steering wheel speed value.

16. The system of claim 11, wherein: The instructions further cause the processor to determine the proportional-integral control value based on the control speed blend value and the error value by multiplying the control speed blend value by the error value.

17. The system of claim 11, wherein: The instructions further cause the processor to selectively control a steering wheel of the vehicle to return to center based on the hybrid command value by limiting the hybrid command value based on the final desired speed value.

18. The system of claim 11, wherein: The steering wheel is associated with a steer-by-wire steering system.

19. The system of claim 11, wherein: The steering wheel is associated with an electronic power steering system.

20. A device for controlling a steering wheel to return to center, the device comprising: processor; as well as a memory comprising instructions that, when executed by the processor, cause the processor to: determining a desired speed value based on a vehicle speed value indicating a speed of the vehicle and a steering wheel position value indicating a position of a steering wheel of the vehicle; determining a control speed blend value based on the vehicle speed value and a driver-applied steering wheel torque value indicative of an amount of torque applied to the steering wheel by a driver of the vehicle; determining a final desired speed value based on the desired speed value and the control speed blend value; determining a proportional-integral control value based on the control speed blend value and an error value associated with the final desired speed value; determining a static return command value based on the steering wheel position value and the vehicle speed value; determining a hybrid command value based on the proportional-integral control value and the static return command value; as well as A steering wheel of the vehicle is selectively controlled to return to center based on the hybrid command value.

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