Method for managing dynamic variable ratio and misalignment in a steer-by-wire system

Abstract

Methods for managing dynamic variable ratio and misalignment in a steer-by-wire system. A method for obtaining a hybrid target rack position curve includes using one or more processors to: calculate a first target rack position curve based on a first vehicle speed; control a rack position based on the first target rack position curve while traveling at the first vehicle speed; in response to a change in a steering wheel position and a transition to a second vehicle speed, calculate the hybrid target rack position curve using both the first target rack position curve and an offset factor corresponding to the second vehicle speed; and control the rack position based on the hybrid target rack position curve.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 727,310, filed December 3, 2024. The entire disclosure of the above-cited applications is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a steer-by-wire (SbW) system. Background Technology

[0004] Vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transportation) typically include a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) system, a hydraulic steering system, or other suitable steering system. The steering system of such vehicles typically controls various aspects of the vehicle's steering, including providing steering assistance to the operator, controlling the steering wheel, etc. Summary of the Invention

[0005] A method for obtaining a hybrid target rack position curve includes: using one or more processors: calculating a first target rack position curve based on a first vehicle speed; controlling a rack position based on the first target rack position curve while traveling at the first vehicle speed; calculating a hybrid target rack position curve using both the first target rack position curve and an offset factor corresponding to the second vehicle speed in response to a change in steering wheel position and a transition to a second vehicle speed; and controlling the rack position based on the hybrid target rack position curve.

[0006] Among other features, one or more systems are configured to perform steps or functions of the methods described herein.

[0007] Among other features, one or more controllers, computing devices, processors, processing devices, etc., are configured to perform the steps or functions of the methods described herein. For example, one or more processors are configured to execute instructions stored in memory to perform the methods described herein. Attached Figure Description

[0008] This disclosure is best understood in conjunction with the accompanying drawings, based on the following description. It should be emphasized that, in accordance with conventional practice, the various features in the drawings are not necessarily drawn to scale. Instead, for clarity, the dimensions of the various features have been arbitrarily enlarged or reduced.

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

[0010] Figure 1B A controller based on the principles of this disclosure is shown in general.

[0011] Figure 2 An example rack or RWA controller and column or steering wheel actuator (HWA) of a steering system according to the principles of this disclosure are generally shown.

[0012] Figure 3 The following is a general example of two different rack position target curves as a function of steering wheel angle for two different vehicle speeds, based on the principles of this disclosure.

[0013] Figure 4 An example of a hybrid rack position target based on the principles of this disclosure is shown in general.

[0014] Figure 5 An example of the (incremental) ΔC factor based on the principles of this disclosure is shown in general.

[0015] Figure 6 The steps of an example method for implementing a technique for transitioning between target rack position curves, based on the principles of this disclosure, are generally shown. Detailed Implementation

[0016] The following discussion focuses on various embodiments of this disclosure. While one or more of these embodiments may be preferred, the disclosed embodiments should not be construed as or otherwise used to limit the scope of this disclosure (including the claims). Furthermore, those skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is merely illustrative of that embodiment and is not intended to imply that the scope of this disclosure (including the claims) is limited to that embodiment.

[0017] As described, vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transportation) typically include a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) system, a hydraulic steering system, or other suitable steering system. The steering system of such vehicles typically controls various aspects of the vehicle's steering, including providing steering assistance to the vehicle's operator, controlling the vehicle's steering wheel, etc.

[0018] The SbW steering system eliminates the mechanical connection between the steering wheel (i.e., the steering wheel itself) and the road wheels. Instead, the SbW steering system uses a steering wheel position sensor to sense the driver's movements of the steering wheel in order to determine the desired rack and road wheel positions. This elimination of the mechanical connection between the steering wheel and road wheels allows for dynamic changes in the C-factor, or steering ratio, which can be done for different operating modes and based on other variables such as vehicle speed. Typically, the C-factor defines the relationship between the rotation of the steering wheel and the linear movement of the steering rack (e.g., expressed as the linear distance traveled per revolution of the pinion).

[0019] In some examples, if the vehicle speed changes while the steering wheel angle is not at zero degrees, the rack position target changes, which can lead to unintended / unintended changes in the vehicle's lateral movement even when the driver has not changed the steering wheel position. Such unintended changes in lateral movement can be minimized by applying slew rates, filters, etc. An alternative approach is to fix the rack position target curve when the driver turns away from the center (i.e., the steering wheel angle is 0 degrees) and then change the target curve when the driver returns to the center.

[0020] An additional aspect of eliminating the mechanical connection between the steering wheel and the road wheels is that they may become misaligned. When misaligned, the actual steering wheel and rack positions do not follow the path specified by the rack position target (e.g., as represented by the target rack position curve). In this case, the system needs a method to align the steering wheel and road wheels back with the target rack position curve.

[0021] The systems and methods disclosed herein implement techniques for transitioning between target rack position curves in a manner that matches not only the target rack position when passing through the center but also the slope (or C-factor) when passing through the center. These systems and methods address ratio / target position curve alterations and misalignments.

[0022] Figure 1A A vehicle 10 based on the principles of this disclosure is generally shown. Vehicle 10 may include any suitable vehicle, such as a car, truck, SUV, minivan, crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although vehicle 10 is shown as a wheeled passenger vehicle intended for use on a road, the principles of this disclosure can be applied to other vehicles, such as airplanes, ships, trains, drones, or other suitable vehicles.

[0023] Vehicle 10 includes a vehicle body (fuselage) 12 and an engine hood 14. A passenger compartment 18 is defined at least partially by the vehicle body 12. Another portion of the vehicle body 12 defines an engine compartment 20. The engine hood 14 may be movably attached to a portion of the vehicle body 12 such that when the engine hood 14 is in a first position or open position, the engine hood 14 provides access to the engine compartment 20, and when the engine hood 14 is in a second position or closed position, the engine hood 14 covers the engine compartment 20. In some embodiments, the engine compartment 20 may be located at the rear of the vehicle 10, rather than in the generally illustrated case.

[0024] The passenger compartment 18 may be located behind the engine compartment 20, but in an embodiment where the engine compartment 20 is located at the rear of the vehicle 10, the passenger compartment may be located in front of the engine compartment 20. The vehicle 10 may include any suitable propulsion system, including: an internal combustion engine, one or more electric motors (e.g., for an electric vehicle), one or more fuel cells, a hybrid propulsion system including a combination of an internal combustion engine and one or more electric motors (e.g., for a hybrid vehicle), and / or any other suitable propulsion system.

[0025] In some embodiments, vehicle 10 may include a petroleum (British gasoline) or gasoline (American gasoline) fuel engine, such as a spark-ignition engine. In some embodiments, vehicle 10 may include a diesel fuel engine, such as a compression-ignition engine. Engine compartment 20 houses and / or encloses at least some components of the propulsion system of vehicle 10. Additionally or alternatively, propulsion controllers (such as accelerator actuators (e.g., accelerator pedal), brake actuators (e.g., brake pedal), steering wheel, and other such components) are disposed in passenger compartment 18 of vehicle 10. The propulsion controllers may be actuated or controlled by the operator of vehicle 10 and may be directly connected to corresponding components of the propulsion system, such as throttle, brakes, vehicle axles, vehicle transmission, etc. In some embodiments, the propulsion controllers may transmit signals to a vehicle computer (e.g., drive-by-wire), which in turn may control the corresponding propulsion components of the propulsion system. Therefore, in some embodiments, vehicle 10 may be an autonomous vehicle.

[0026] In some embodiments, vehicle 10 includes a transmission connected to a crankshaft via a flywheel, clutch, or hydraulic coupler. In some embodiments, the transmission includes a manual transmission. In some embodiments, the transmission includes an automatic transmission. In the case of an internal combustion engine or hybrid vehicle, vehicle 10 may include one or more pistons that operate in cooperation with the crankshaft to generate force, which is transmitted via the transmission to one or more shafts to rotate wheels 22. When vehicle 10 includes one or more electric motors, a vehicle battery and / or fuel cell provides power to these electric motors to rotate wheels 22.

[0027] Vehicle 10 may include an autonomous vehicle propulsion system, such as cruise control, adaptive cruise control, automatic braking control, other autonomous vehicle propulsion systems, or combinations thereof. Vehicle 10 may be an autonomous or semi-autonomous vehicle, or other suitable type of vehicle. Vehicle 10 may include more or fewer features than those generally illustrated and / or disclosed herein.

[0028] In some embodiments, vehicle 10 may include an Ethernet component 24, a Controller Area Network (CAN) bus 26, a Media-Oriented System Transport (MOST) component 28, a FlexRay component 30 (e.g., a brake-by-wire system), and a Local Interconnect Network (LIN) component 32. Vehicle 10 may use the CAN bus 26, MOST 28, FlexRay component 30, LIN 32, other suitable network or communication systems, or combinations thereof, to transmit various information from sensors, such as those inside or outside the vehicle, to various processors or controllers, such as those inside or outside the vehicle. Vehicle 10 may include more or fewer features than those generally illustrated and / or disclosed herein.

[0029] In some embodiments, vehicle 10 may include a steering system, such as an EPS system, a steer-by-wire system (e.g., which may include one or more controllers or communicate with one or more controllers, which control components of the steering system without using the mechanical connection between the steering wheel and the wheels 22 of vehicle 10), a hydraulic steering system (e.g., which may include a magnetic actuator incorporated into a valve assembly of a hydraulic steering system), or other suitable steering systems.

[0030] 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.

[0031] Additionally or alternatively, these inputs may include steering wheel torque, steering wheel angle, motor speed, vehicle speed, estimated motor torque command, other suitable inputs, or combinations thereof. The steering system may be configured to provide steering functionality and / or control to the vehicle 10. For example, the steering system may generate auxiliary torque based on various inputs. The steering system may be configured to use the auxiliary torque to selectively control the motor of the steering system to provide steering assistance to the operator of the vehicle 10.

[0032] In some implementations, the vehicle 10 includes one or more controllers, such as in Figure 1B The controller 100 is generally illustrated herein. Controller 100 may correspond to a steering system controller. Controller 100 may include any suitable controller, such as an electronic control unit or other suitable controller. Controller 100 may be configured to control various functions, such as those of the steering system and / or various functions of the vehicle 10. Controller 100 may include a processor 102 and a memory 104. Processor 102 may include any suitable processor, such as those described herein. Additionally or alternatively, controller 100 may include any suitable number of processors as a complement to or alternative to processor 102. Memory 104 may include a single disk or multiple disks (e.g., a hard disk drive) and includes a storage management module that manages one or more partitions within memory 104. In some embodiments, memory 104 may include flash memory, semiconductor (solid-state) memory, etc. Memory 104 may include random access memory (RAM), read-only memory (ROM), or a combination thereof. Memory 104 may include instructions that, when executed by processor 102, cause processor 102 to control at least various aspects of the vehicle 10. Additionally or alternatively, memory 104 may include instructions that, when executed by processor 102, cause processor 102 to perform functions associated with the systems and methods described herein.

[0033] The controller 100 may receive one or more signals from various measuring devices or sensors 106 indicating sensed or measured characteristics of the vehicle 10. Sensors 106 may include any suitable sensors, measuring devices, and / or other suitable mechanisms. For example, sensors 106 may include one or more torque sensors or devices, one or more steering wheel position sensors or devices, one or more motor position sensors or devices, one or more position sensors or devices, other suitable sensors or devices, or combinations thereof. The one or more signals may indicate steering wheel torque, steering wheel angle, motor speed, vehicle speed, other suitable information, or combinations thereof.

[0034] As used herein, "controller" can refer to a hardware module or component including one or more processors or microcontrollers, memory, sensors, one or more actuators, communication interfaces, etc., any part of which can be collectively referred to as "circuit". As described herein, the corresponding functions and steps performed by a given controller, control circuit, etc., can be performed jointly by multiple controllers, processors, etc. For example, a processor, processing device, controller, control circuit, etc., "configured to perform" can refer to a single processor, processing device, controller, etc., configured to perform both A and B, or it can refer to a first processor, processing device, controller, etc., configured to perform A and a second processor, processing device, controller, etc., configured to perform B. For simplicity, "control circuit configured to perform A and B" can refer to a single or multiple processors, processing devices, controllers, etc., collectively configured to perform A and B.

[0035] In some embodiments, controller 100 may perform the functions of the systems and methods described herein. However, the methods described herein, performed by controller 100, are not intended to be limiting, and any type of software executing on a controller, processor, or other circuitry may implement the techniques described herein without departing from the scope of this disclosure. For example, a controller (such as a processor that executes software within a computing device) may implement the systems and methods described herein.

[0036] Figure 2 An example steering system 200 according to this disclosure is illustrated, including a rack or RWA controller 202 and a column or steering wheel actuator (HWA) controller 204 configured to implement the steering system of the technology. For example, the HWA controller 204 is configured to generate a steering wheel actuator (HWA) motor torque command based on an estimated rack force (e.g., an estimated rack force signal) received from the RWA controller 202 and one or more other input signals (e.g., vehicle speed, steering wheel position, and steering wheel speed). The RWA controller 202 is configured to determine the estimated rack force based on the motor torque required to achieve or maintain the actual rack position. Controllers 200 and 204 may correspond to, be implemented by, or correspond to one or more steering system controllers.

[0037] As an example, the HWA controller 204 includes a reference torque calculator 208, which is configured to calculate a reference torque (T) based on an estimated rack force and one or more other input signals. refFor example, the reference torque corresponds to the sum of various inputs / measurements (such as applied force, hysteresis, return correction or CVR, damping, catch mechanism, etc.). The closed-loop (e.g., PID closed-loop) torque controller 212 is configured to generate and output a motor torque command based at least in part on the force or torque applied by the driver (e.g., "Tbar torque") and the reference torque. The motor torque command is provided as a control signal to control the motor of the steering wheel actuator.

[0038] The estimated rack force corresponds to the measured or estimated torque of the wheel actuator motor. Therefore, the estimated rack force (and any estimated rack force offset or error) is a key factor in determining the force provided by the motor of the steering wheel actuator.

[0039] In some examples, the HWA controller 204 may also include a C-factor lookup module 216 and a rack position reference calculator 220. Although shown as being implemented in the HWA controller 204, one or more of the C-factor lookup and rack position reference calculation may alternatively be implemented by the RWA controller 202. For example, the rack position reference calculator 220 is configured to generate a rack position reference based on a C-factor received from the C-factor lookup module 216. The C-factor may be determined based on a steering wheel angle (“HwAg”) corresponding to a driver input (e.g., a steering wheel angle indicating the driver’s intention conveyed via the steering wheel). An example system and method for obtaining a rack position reference and a C-factor are described in more detail in U.S. Patent Application No. 18 / 318,657, filed May 16, 2023, the entire contents of which are incorporated herein by reference.

[0040] RWA controller 202 includes rack position controller 224 (e.g., PID rack position controller) configured to generate one or more rack position control signals based on the actual rack position and a rack position reference (e.g., based on the difference between the actual rack position and the rack position reference). For example, the rack position control signals may include, but are not limited to, rack motor speed and motor torque commands (e.g., signals indicating the amount of torque applied by the driver). In this way, the rack position is controlled to follow the driver's intention (as indicated by the rack reference position).

[0041] The rack force predictor 226 generates an estimated rack force based on the output of the rack position controller 224 (e.g., a function of the rack motor speed, rack motor torque commands, etc.). In various examples, the estimated rack force can be calculated based on the amount of torque applied to the steering wheel by the driver (e.g., indicated by rack motor torque commands, various sensor signals, etc.). As shown, the rack force predictor 226 can output the estimated rack force, and a reference torque calculator 208 (and / or another component of the HWA controller 204, RWA controller 202, etc.) can obtain an estimated rack load based on this estimated rack force. In other examples, the rack force predictor 226 can output the estimated rack load. In some cases, the terms "estimated rack force" and "estimated rack load" can be used interchangeably.

[0042] For example, for RWA position control, the rack position reference signal (“RackPosRef”) can be calculated based on the position error (“PosErr”) between the ADAS rack position reference value or signal (“ADASRackPosRef”) and the HWA rack position reference value or signal (“HWARackPosRef”). Conversely, HWA position control is based on the position error between the HWA position and the RWA position, allowing the steering wheel to be controlled to rotate in a manner consistent with the rotation of the road wheels when hands-off (without interference).

[0043] The reference torque can correspond to the desired, ideal, or target torque that the driver (i.e., at the steering wheel) will feel. As described above, the reference torque is calculated based on inputs including, but not limited to, driver input (e.g., input torque corresponding to the steering wheel angle), road conditions, damping, hysteresis, etc. (e.g., via HWA) to control the torque at the steering wheel to match the reference torque. For example, the outputs of one or more sensors measuring the actual torque at the wheels are used to minimize the difference between the reference torque and the actual torque.

[0044] A force function (e.g., a force function implemented by the reference torque calculator 208) defines the relationship between driver input (e.g., the force or torque applied by the driver to the steering wheel, which may be referred to as "force") and the response (i.e., movement) of the steering system. For example, the force function may output a force value based on a lookup table or other function (e.g., by using an estimated rack load as input). The estimated rack load may be modified before being input into the lookup table by adding the calculated return load value to the estimated rack load. The force function indicates the amount of force required by the driver to elicit the desired response.

[0045] The steering system 200 according to this disclosure is configured to achieve the following technique: switching between target rack position curves in a manner that matches not only the target rack position when passing the center but also the slope (or C factor) when passing the center, as described in more detail below.

[0046] Figure 3 Examples of two different rack position target curves 300 and 304 as a function of steering wheel angle are shown for two different vehicle speeds. Curves 300 and 304 can be generated using lookup tables (LUTs) or other methods (e.g., functions or algorithms, models, etc.). As shown, if the vehicle speed changes while the steering wheel angle is not zero degrees (e.g., from the first vehicle speed corresponding to 300 to the second vehicle speed corresponding to 304), the rack position target changes, which can lead to undesirable / unintended changes in the lateral movement of the vehicle even when the driver has not changed the steering wheel position. Such undesirable changes in lateral movement can be minimized by applying conversion rates, filters, etc.

[0047] An alternative approach is to fix the target rack position curve when the driver turns away from the center (i.e., the steering wheel angle is 0), and then change the target curve when the driver returns to the center. Using this method, the target rack position follows curve 300 in one direction and switches to curve 304 when passing the center (i.e., the steering wheel angle is 0). Although the target position is the same for both curves at the center, there is an immediate change in the slope of the curves (i.e., the slope of curve 300 relative to the slope of curve 304), which results in an undesirable steering feel.

[0048] Figure 4 An example of a mixed rack position target (mixed or combined rack position target curve 400, shown as a dashed line, corresponding to a combination of curves 300 and 304) is illustrated according to the principles of this disclosure. In an example where the driver initiates a turn while the vehicle is traveling at a first vehicle speed (e.g., the speed associated with curve 300) and the vehicle speed increases to a second vehicle speed (e.g., the speed associated with curve 304) during the turn, the rack position target follows curve 300 when turning away from the center (e.g., in the steering wheel angle direction / area shown at 404). However, according to the principles of this disclosure, the rack position target returns and passes through the center on curve 400 (e.g., in the steering wheel angle direction / area shown at 408). Curve 400 corresponds to the mixed position (the combination of curves 300 and 304). Thus, as shown, when the driver returns, the rack position target passes through the center (i.e., crosses...). Figure 4When crossing the center axis, curve 400 matches curve 304 in both slope and position. In this way, the abrupt change in slope (and steering feel) caused by the change from curve 300 to curve 304 when crossing the center is avoided.

[0049] Using the hybrid technique of this disclosure, the target rack position (X) corresponding to curve 400 is determined by fixing the target curve at a point where the driver turns away from the center (“fixed curve position”) and adding an offset (Δx) to the target rack position X, as follows: , The LUT is determined at the fixed curve position. θ ), and determine Δx for the operating conditions that determine the target rack position curve (such as vehicle speed). θ For example, Δx can be determined based on the actual vehicle speed (rather than the vehicle speed obtained using curve 300). θ (This can be referred to as the offset or adjustment factor), the actual vehicle speed can be the same as or different from the vehicle speed corresponding to curve 304. Therefore, when the driver returns towards the center (as in...) Figure 4 As shown in direction 408, as the driver approaches the center, curve 400 begins to curve in the direction corresponding to Δx ( θ The amount of deviation of curve 400 from curve 300 is (e.g., at least in part based on vehicle speed). In this way, when the driver reaches the center position, curve 400 matches curve 304 in both slope and position.

[0050] To ensure that the slopes of the target curves approaching a position (e.g., curve 400 when the driver is returning towards the center in direction 408) and leaving that position (e.g., curve 304) always match, the C-factor can be constrained based on how much the position changes. This is used to generate the ΔC-factor curve. To match the slope when crossing the center, the C-factor is determined at a fixed target speed (CF0fxd) and the actual speed (CF0) (e.g., the C-factor at the steering wheel angle "0", or "on-center C-factor"). The difference between these two values ​​is the expected ΔC-factor when crossing zero (0). Using these two values, the expected ΔC-factor curve can be determined by matching the C-factor at the current angle and at zero. To ensure that the target rack position curve crosses zero, the integral of the curve (i.e., the area under the curve) is zero. Satisfying all these conditions allows for the creation of a ΔC-factor curve where both position and slope match when crossing the center.

[0051] Figure 5An example of the (incremental) ΔC factor 500 according to the principles of this disclosure is shown. As shown, the ΔC factor 500 curve consists of linear segments, but any set of functions or segments can be used to construct the curve. In this example, when turning away from the center, the driver is operating on the first vehicle speed target rack position curve 300, such as... Figure 4 As shown. When the driver turns back towards the center, an incremental C factor of 500 is applied, and a rack position offset (Δx) is added to the rack position target. When the driver's turn passes zero, the target rack position curve switches to the second vehicle speed target rack position curve 304. At this point, CF0 fxd and CF0 are the same, therefore the ΔC factor is zero.

[0052] If the driver turns away from the center and then turns back towards the center, thus initiating the ΔC factor 500 curve, and turns away from the center again, the driver will follow the ΔC factor 500 curve until the fixed target rack position curve is reached.

[0053] Using this method, the ΔC factor curve is constrained using at least minimum C-factor, maximum C-factor, and maximum ΔC factor / degree calibrations. In one example, minimum C-factor, maximum C-factor, and maximum ΔC factor / degree calibrations are used to determine the minimum and maximum ΔC factors. These calibrations can be functions of vehicle speed and / or other variables. These constraints can prevent the generation of ΔC factor curves that match both slope and position when crossing zero, or prevent matching a fixed target rack position when turning away from the center. For these conditions, a priority can be set to match either slope or position. For example, when crossing the center, the priority can be set to cross zero at a slope close to that allowed by the ΔC factor constraint. In the same way, the priority can be to match the slope when turning away from the center, even if the position does not match. If the position does not match under these conditions, the result is misalignment. This misalignment is reduced and eliminated when the system is turned back through the center using a ΔC factor 500 curve. If the amount of misalignment exceeds the ΔC factor constraint, multiple passes through the center may be required to completely eliminate the misalignment.

[0054] The rack position offset (Δx) is described in this paper as the steering wheel angle ( θ The function of rack position (x). However, these techniques can also be used to determine the steering wheel angle offset (Δ) as a function of rack position (x). θ In another example, the target rack position (X) can be determined based on the following: .

[0055] In this example, the inverse C-factors at zero (1 / CF0) and (1 / CF0fxd) are used to create the desired Δ inverse C-factor curve. The integral of the Δ inverse C-factor curve provides Δ θ Value. In the various examples described herein, the offset or adjustment of the rack position curve (e.g., Δx) θ ), Δ θ (etc.) can be referred to as the offset or adjustment factor, which can be determined based on the ΔC factor as described above.

[0056] Figure 6 The steps of an example method 600 for implementing a technique for transitioning between target rack position curves, based on the principles of this disclosure, are generally illustrated. The steps of method 600 can be implemented by systems and components described herein, such as controller 100, system 200, one or more computing devices, processors, or processing devices (e.g., one or more processing devices configured to execute instructions stored in memory).

[0057] At 604, method 600 includes calculating a first target rack position based on the speed of a first vehicle. At 608, method 600 includes controlling the rack position based on the first target rack position while traveling at the speed of the first vehicle. At 612, method 600 includes calculating a center-on-center C-factor (first-on-center C-factor) for the speed of the first vehicle and a center-on-center C-factor (second-on-center C-factor) for the speed of a second vehicle. At 616, method 600 includes calculating a mixed target rack position using the first target rack position, the first center-on-center C-factor, and the second center-on-center C-factor in response to a change in steering wheel position and a change to the speed of the second vehicle (i.e., a transition to the speed of the second vehicle). At 620, method 600 includes controlling the rack position based on the mixed target rack position.

[0058] Therefore, as described herein, the systems and methods of this disclosure implement techniques for: managing a dynamically variable ratio to match the C-factor and position when the steering wheel position crosses zero degrees; generating a rack position offset using an incremental C-factor; using the rack position offset to transition between target rack position curves; using an incremental C-factor curve to correct misalignment; generating a steering wheel angle offset using an incremental reciprocal C-factor; using the steering wheel angle offset to transition between target rack position curves; and using an incremental reciprocal C-factor curve to correct misalignment.

[0059] The foregoing discussion is intended to illustrate the principles and various embodiments of the invention. Many variations and modifications will become apparent to those skilled in the art once the foregoing disclosure is fully understood. The appended claims are intended to be construed as covering all such variations and modifications.

[0060] The word “example” is used herein to indicate that something is used as an example, instance, or illustration. No aspect or design described herein as an “example” is necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, the use of the word “example” is intended to present the concept in a specific manner. As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or clearly understood from the context, “X comprises A or B” is intended to mean any of the natural inclusive permutations and combinations. That is, if X comprises A; X comprises B; or X comprises both A and B, then “X comprises A or B” is satisfied in any of the foregoing examples. Additionally, the articles “a” and “an” as used herein and in the appended claims should generally be interpreted as meaning “one or more” unless otherwise specified or clearly understood from the context to refer to the singular form. Furthermore, the use of the terms “one embodiment” or “an embodiment” throughout is not intended to refer to the same embodiment or implementation unless specifically described as such.

[0061] The systems, algorithms, methods, instructions, etc., described herein can be implemented in hardware, software, or any combination thereof. Hardware may include, for example, a computer, intellectual property (IP) core, application-specific integrated circuit (ASIC), programmable logic array, optical processor, programmable logic controller, microcode, microcontroller, server, microprocessor, digital signal processor, or any other suitable circuitry. In the claims, the term "processor" should be understood to cover any of the aforementioned hardware, individually or in combination. The terms "signal" and "data" are used interchangeably. As used herein, the terms "approximately" or "about" may correspond to values, variables, etc., within + / - 5%.

[0062] As used herein, the term "module" can include packaged functional hardware units designed for use with other components, instruction sets executable by a controller (e.g., a processor executing software or firmware), processing circuitry configured to perform specific functions, and stand-alone hardware or software components that interface with a larger system. For example, a module can include application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), circuits, digital logic circuits, analog circuits, combinations of discrete circuits, gates, and other types of hardware, or combinations thereof. In other embodiments, a module can include memory storing instructions that can be executed by a controller to implement the features of the module.

[0063] Furthermore, in one aspect, for example, the system described herein can be implemented using a general-purpose processor or general-purpose computer with a computer program that, when executed, implements any of the various methods, algorithms, and / or instructions described herein. Additionally or alternatively, for example, a special-purpose computer / processor may be utilized, which may include other hardware for implementing any of the methods, algorithms, or instructions described herein.

[0064] Furthermore, all or part of the embodiments of this disclosure may take the form of a computer program product accessible from, for example, a computer-usable medium or a computer-readable medium. A computer-usable medium or a computer-readable medium may be any means capable of, for example, tangibly containing, storing, transmitting, or transporting a program for use by or in conjunction with any processor. Such a medium may be, for example, an electronic, magnetic, optical, electromagnetic, or semiconductor device. Other suitable media are also available.

[0065] The above embodiments, implementation methods, and aspects have been described to allow for an easy understanding of the invention and are not intended to limit it. Rather, the invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, and its scope should be interpreted in the broadest possible sense to cover all such modifications and equivalent structures permitted under the law.

Claims

1. A method for obtaining a hybrid target rack position curve, the method comprising using one or more processors: The position curve of the first target rack is calculated based on the speed of the first vehicle. The rack position is controlled based on the first target rack position curve while traveling at the speed of the first vehicle; In response to changes in steering wheel position and a shift in speed to the second vehicle, the hybrid target rack position curve is calculated using both the first target rack position curve and an offset factor corresponding to the speed of the second vehicle; and The rack position is controlled based on the hybrid target rack position curve.

2. The method according to claim 1, wherein, Calculating the hybrid target rack position curve includes: calculating the offset factor based on the C factor.

3. The method according to claim 2, wherein, Calculating the offset factor based on the C factor includes: calculating the offset factor based on at least one C factor at the center.

4. The method according to claim 1, further comprising: When traveling at the speed of the first vehicle and in response to the movement of the steering wheel position in the first direction, the rack position is controlled based on the first target rack position curve; as well as In response to the steering wheel position moving in the second direction, the rack position is controlled based on the hybrid target rack position curve.

5. The method according to claim 1, wherein, The hybrid target rack position curve lies between the first target rack position curve and the second target rack position curve.

6. The method according to claim 5, wherein, The position of the hybrid target rack is calculated such that the first slope of the hybrid target rack position curve at a steering wheel angle of 0 is approximately equal to the second slope of the second target rack position curve.

7. The method according to claim 1, further comprising: According to X = LUT( θ ) + Δx( θ The LUT (Least Usage Threshold) is used to calculate the hybrid target rack position curve, where X is the hybrid target rack position curve. θ ) corresponds to the first target rack position curve, and Δx( θ ) is the offset factor.

8. The method according to claim 7, wherein, LUT( θ This corresponds to the first target rack position curve at the steering wheel angle θ.

9. A processor configured to execute instructions stored in a memory, wherein, Executing the instructions causes the processor to obtain the hybrid target rack position curve as follows: The position curve of the first target rack is calculated based on the speed of the first vehicle. The rack position is controlled based on the first target rack position curve while traveling at the speed of the first vehicle; In response to changes in steering wheel position and a change in speed to the second vehicle, the hybrid target rack position curve is calculated using both the first target rack position curve and an offset factor corresponding to the speed of the second vehicle. as well as The rack position is controlled based on the hybrid target rack position curve.

10. The processor according to claim 9, wherein, Calculating the hybrid target rack position curve includes: calculating the offset factor based on the C factor.

11. The processor according to claim 10, wherein, Calculating the offset factor based on the C factor includes: calculating the offset factor based on at least one C factor at the center.

12. The processor according to claim 9, wherein, Executing the instructions also causes the processor to: When traveling at the speed of the first vehicle and in response to the movement of the steering wheel position in the first direction, the rack position is controlled based on the first target rack position curve; as well as In response to the steering wheel position moving in the second direction, the rack position is controlled based on the hybrid target rack position curve.

13. The processor according to claim 9, wherein, The hybrid target rack position curve lies between the first target rack position curve and the second target rack position curve.

14. The processor according to claim 9, wherein, The position of the hybrid target rack is calculated such that the first slope of the hybrid target rack position curve at a steering wheel angle of 0 is approximately equal to the second slope of the second target rack position curve.

15. The processor according to claim 9, wherein, Executing the instructions also enables the processor to operate according to X = LUT( θ ) + Δx( θ The LUT (Least Usage Threshold) is used to calculate the hybrid target rack position curve, where X is the hybrid target rack position curve. θ ) corresponds to the position of the first target rack, and Δx( θ ) is the offset factor.

16. The processor of claim 15, wherein, LUT( θ This corresponds to the first target rack position curve at the steering wheel angle θ.

17. A system comprising: One or more sensors are configured to generate signals corresponding to the operating characteristics of the vehicle; and The controller is configured to receive the signal and, based on the signal: The position curve of the first target rack is calculated based on the speed of the first vehicle. The rack position is controlled based on the first target rack position curve while traveling at the speed of the first vehicle; In response to changes in steering wheel position and a change in speed to the second vehicle, the hybrid target rack position curve is calculated using both the first target rack position curve and an offset factor corresponding to the speed of the second vehicle. as well as The rack position is controlled based on the hybrid target rack position curve.

18. The system according to claim 17, wherein, The controller is also configured to: When traveling at the speed of the first vehicle and in response to movement of the steering wheel position in the first direction, the rack position is controlled based on the first target rack position curve, and In response to the steering wheel position moving in the second direction, the rack position is controlled based on the hybrid target rack position curve.

19. The system according to claim 17, wherein, Calculate the hybrid target rack position curve such that the first slope of the hybrid target rack position curve at a steering wheel angle of 0 is approximately equal to the second slope of the second target rack position curve.

20. A means of transport comprising the system according to claim 17.

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