System and method for automated control of vehicle turn assist features

Abstract

The present disclosure provides a system and method for automatic control of a vehicle turn assist feature. A vehicle control system may include a mode selector including at least a turn assist mode selectable by an operator of a vehicle to activate a turn assist feature; a controller for employing the turning assist feature by directly applying a brake torque to an inside rear wheel of the vehicle during turning when a trigger condition for implementing the turning assist feature may be detected; and a [mu] detection module for estimating a [mu] condition of a surface on which the vehicle is operable. The controller may also automatically generate a blocking signal to block operation of the turn assist feature in response to the [mu] detection module estimating a minimum [mu] value of the surface that may be less than a threshold [mu] value.

Description

Technical Field

[0001] Example embodiments relate generally to vehicle control technology and, more particularly, to a system and method for activating a reduced turning radius feature of a vehicle. Background Art

[0002] Vehicles with relatively long wheelbases, such as trucks, also typically have large turning radii. This can make such vehicles difficult to park or maneuver in relatively tight spaces. In some cases, such vehicles may also have difficulty completing U-turns. Larger front-wheel drive vehicles may also face similar problems. Therefore, a turning radius reduction feature can be implemented to provide a more satisfying user experience for drivers of these and other vehicles.

[0003] However, activating the turning radius reduction feature may not be advantageous under certain driving conditions. Therefore, it may be desirable to develop systems and methods for automatically controlling the turning radius reduction feature to provide a more satisfying user experience for drivers of these and other vehicles. Summary of the invention

[0004] According to an example embodiment, a vehicle control system for a vehicle may be provided. The vehicle control system may include: a mode selector, the mode selector including at least a turn assist mode, the turn assist mode selectable by an operator of the vehicle to activate a turn assist feature; a controller, the controller for employing the turn assist feature by directly applying a braking torque to an inside rear wheel of the vehicle during a turn when a trigger condition for implementing the turn assist feature may be detected; and a μ detection module, the μ detection module for estimating a μ condition of a surface on which the vehicle may operate. The controller may also automatically generate a blocking signal to block operation of the turn assist feature in response to the μ detection module estimating a minimum μ value of the surface that may be less than a threshold μ value.

[0005] In another example embodiment, a method of automatically controlling application of a turn assist feature in a vehicle is provided. The method may include estimating, via a μ detection module, a μ condition of a surface on which the vehicle may operate, receiving a mode selection selecting a turn assist mode, receiving steering wheel angle and vehicle speed information to determine whether a trigger condition for implementing the turn assist feature may be satisfied during a turn, applying a negative torque to an inside rear wheel in response to detecting the trigger condition for implementing the turn assist feature, and automatically generating a blocking signal to block operation of the turn assist feature in response to the μ detection module estimating a minimum μ value of the surface that may be less than a threshold μ value. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Having thus generally described the invention, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0007] Figure 1 shows a block diagram of a vehicle control system according to an example embodiment;

[0008] Figure 2 According to an example embodiment, Figure 1 A block diagram of some components of a vehicle control system;

[0009] Figure 3 shows a block diagram of a vehicle control system according to an example embodiment;

[0010] Figure 4 shows a decision making flow chart of a controller according to an example embodiment;

[0011] Figure 5 shows a decision making flow chart of a controller according to an example embodiment; and

[0012] Figure 6 A method of controlling a vehicle according to an example embodiment is shown. DETAILED DESCRIPTION

[0013] Some example embodiments will now be described more fully below with reference to the accompanying drawings, in which some but not all example embodiments are shown. In fact, the examples described and depicted herein should not be construed as limiting the scope, applicability or configuration of the present disclosure. Rather, these example embodiments are provided so that the present disclosure will meet applicable requirements. The same reference numerals always refer to the same elements. In addition, as used herein, the term "or" will be interpreted as a logical operator whose result is true whenever one or more of its operands are true. As used herein, an operable connection should be understood to involve a direct or indirect connection, in which case the connection enables the functional interconnection of components that are operably connected to each other.

[0014] As described above, it may be desirable to develop a system and method for automatically controlling a turning radius reduction feature. That is, strategies that may work in the context of large vehicles may also work for other vehicles. Therefore, the example embodiments are not strictly limited to application in large vehicles.

[0015] It may be possible to use braking torque to assist in turning radius reduction via a technique commonly referred to as brake steering or brake assisted turning. However, it may be desirable to provide a system that can improve the performance of brake steering or brake assisted turning. Example embodiments may provide such improvements by implementing strategic control of both positive and negative torques applied to the wheels of the front axle and the wheels of the rear axle during turning. By applying a negative torque to the rear inside wheel during turning, and applying a positive torque to the front wheel to pull the vehicle through the turn, not only can the vehicle turning radius be reduced, but the user experience during the application of the turning radius reduction can also be made smoother. However, such a turning assist feature may only be desirable under driving conditions with sufficient grip on the driving surface. Under conditions of low grip, the turning assist feature should be disabled or completely blocked. Example embodiments may provide strategic control of the turning assist feature based on automatic calculation of the μ condition of the surface on which the vehicle may operate.

[0016] Thus, some example embodiments may provide a system that is not only capable of providing a turn assist feature to reduce the turning radius in an automatic manner that is seamless to the driver, but is also capable of monitoring the condition of the driving surface and automatically generating a blocking signal to block the operation of the turn assist feature in response to detecting a slippery driving surface. In this regard, for example, a controller of a system of an example embodiment may be configured to automatically apply a negative torque to the rear inside wheel and a positive torque to the front wheel during a sharp turn. In some cases, the application of such a balancing torque may be determined based on or otherwise incorporate or take into account wheel slip, which is a measure of the rotational speed difference between certain wheels. For example, wheel slip of the rear inside wheel may be determined and may be controlled during application of a turning radius reduction strategy. The controller may also use wheel slip to detect a loss or reduction in friction between the wheel and the surface and automatically control the turn assist feature accordingly.

[0017] Figure 1 1 shows a block diagram of a control system 100 of an example embodiment. Components of the control system 100 may be incorporated into a vehicle 110 (e.g., via an operative connection to a chassis of the vehicle 110, various components of the vehicle 110, and / or an electronic control system of the vehicle 110). It is worth noting that, although Figure 1 The components of the control system 100 may be operably coupled to the vehicle 110, but it should be understood that such connection may be direct or indirect. In addition, some of the components of the control system 100 may be connected to the vehicle 110 via intermediate connections to other components of the chassis or other electronic and / or mechanical systems or components.

[0018] The control system 100 may have a normal operating mode, which includes an input device in the form of a control pedal and a steering wheel (or hand wheel). The pedal may include a brake pedal and an accelerator pedal pivotally mounted to the floor of the vehicle 110 and operable by the operator 125. The brake pedal can generally be used to provide an input for controlling the braking torque, and the accelerator pedal can be used to provide an input for controlling the propulsion torque. However, the normal operating mode may not be applicable to all situations. In addition, there may be other selectable operating modes, including one or more off-road driver assistance modes, parking modes, turn assist modes, etc. Therefore, the control system 100 of some example embodiments may also include a user interface 120. The operator 125 can operate the user interface 120, and the user interface may include or define a mode selector to switch out of the normal operating mode and enter any one of the other operating modes. In an example embodiment, other operating modes that can be selected by the operator 125 via the user interface 120 may include a turn assist mode, in which a turn radius reduction can be initiated, as described in more detail below.

[0019] It is worth noting that although the term turn assist mode is generally referred to herein as a mode for performing example embodiments, the name of the mode in which the example embodiments may be applied is not important and is certainly not limiting. As mentioned above, other terms such as brake steering mode, parking mode, or any other mode in which the functionality described herein is applied are also possible.

[0020] The control system 100 of the example embodiment may also include a torque control module 130, which may be part of or otherwise operably coupled to the controller 140. The torque control module 130 may be configured to determine positive torque (e.g., propulsion torque) and / or negative torque (e.g., braking torque, regeneration torque, etc.) applied to the wheels individually, in pairs, or collectively (e.g., depending on the powertrain state and / or vehicle type) based on input from any or all of the controller 140, the user interface 120, or other components of the vehicle 110, as described herein. In some cases, the controller 140 may be part of an electronic control system of the vehicle 110 that is configured to perform other tasks related or unrelated to propulsion and braking control or performance management. However, in some cases, the controller 140 may be a dedicated or stand-alone controller.

[0021] In an example embodiment, the controller 140 may receive information for determining the vehicle state from various components or subassemblies 150 of the vehicle 110. Additionally or alternatively, various sensors may be included that are operably coupled to the components or subassemblies 150 and may provide input to the controller 140 for determining the vehicle state. Such sensors may be part of a sensor network 160, and the sensors of the sensor network 160 may be operably coupled to the controller 140 (and / or the components or subassemblies 150) via a vehicle communication bus (e.g., a controller area network (CAN) bus) 165.

[0022] Components or subassemblies 150 may include, for example, a steering wheel of the vehicle, a brake assembly of the vehicle 110, a propulsion system, and / or a wheel assembly. The brake assembly may be configured to provide a braking input to a braking component (e.g., friction brakes and electrical braking methods such as regenerative braking) of the vehicle 110 based on a braking torque determined by the controller 140 and / or the torque control module 130. In some cases, the brake assembly may include an electric brake booster (EBB) system that uses an electric brake booster to sense driver input and reduce the amount of pedal pressure required to brake. The propulsion system may include a gas engine, an electric motor, or any other suitable propulsion device.

[0023] The controller 140 and / or the torque control module 130 may be configured to determine positive and negative torque inputs to provide to components of the driveline 170 (e.g., drive shafts, differentials, axle shafts, etc.) and wheels 180 of the vehicle 110. Thus, for example, the torque control module 130 may determine positive torque inputs to provide to the propulsion system to apply propulsion torque to wheels 180 of wheel assemblies of the vehicle 110 via the driveline 170, and determine negative torque inputs in the form of braking torque, regenerative torque, etc. to provide to the wheels 180. Additionally, one or more corresponding sensors of the sensor network 160 that may be operably coupled to the brake assemblies and / or wheel assemblies may provide information related to braking torque, braking torque rate, vehicle speed, vehicle speed change rate, individual wheel speeds, front / rear wheel speeds, vehicle pitch, etc. Other examples of components or subassemblies 150 and / or corresponding sensors of sensor network 160 may provide information related to yaw, lateral G-forces, steering wheel angle, throttle position, selector button positions associated with chassis and / or vehicle control selections, and the like.

[0024] Thus, for example, the controller 140 may be capable of receiving numerous different parameters, indications, and other information that may relate to or indicate different situations or conditions associated with the vehicle state. The controller 140 may also receive information indicative of the operator's 125 intent with respect to controlling various aspects of the operation of the vehicle 110, and may then be configured to use the received information in association with the execution of one or more control algorithms that may be used to provide instructions to the torque control module 130 to control the application of positive and negative torques to the wheels of the wheel assemblies of the vehicle 110.

[0025] In an example embodiment, the operator 125 may use the user interface 120 to select the turn assist mode. The user interface 120 may be implemented by an interactive display in the vehicle 110, and thus may be a soft switch provided on the display. However, in other examples, the user interface 120 may include a hard switch, button, key, or other selectable operator located in the cockpit of the vehicle 110. The selection of the turn assist mode may correspondingly activate the torque control module 130 to provide the automatic turning control described herein based on information provided by corresponding sensors of the component or subassembly 150 and / or the sensor network 160. More specifically, the selection of the turn assist mode may enable control of the turning capability based on vehicle speed, steering wheel position, and control of the negative torque to the inside rear wheel, while providing feed-forward to the front wheels to offset the positive torque. Reference will be made below to Figure 2 The operation of the torque control module 130 is described in further detail.

[0026] As described above, when the torque control module 130 is active and automatic steering control has been activated, the output of the torque control module 130 may be provided to components of the driveline 170 of the vehicle 110. Thus, the controller 140 may receive information to enable the controller 140 to determine the state of the driveline 170 of the vehicle 110, or the specific driveline 170 characteristics of the vehicle type involved may be programmed into an algorithm that can be executed by the controller 140. The driveline 170 may include a front axle and a rear axle, as well as various drive components of the front axle and the rear axle and / or components that provide a connection between them. Thus, for example, the driveline 170 may include a differential (e.g., a front differential of a front wheel drive vehicle) that operably connects the front axle and the rear axle (and / or its drive components) and gears and / or clutch components. In some examples, such as when the vehicle 110 is a battery electric vehicle (BEV), the driveline 170 may include a separate electric motor for each axle or even each wheel.

[0027] Reference now Figure 2 , the operations of the controller 140 and the torque control module 130 will be described in more detail. Figure 2 1 shows a block diagram of various components of the control system 100 in more detail. In this regard, for example, Figure 2 An example interaction between the controller 140 and the torque control module 130 with respect to information received thereby (e.g., from the sensor network 160, from each of the components / subassemblies 150, and / or from the user interface 120) is shown. Processing circuitry at the controller 140 (e.g., the processor 210 and the memory 220) may process the received information by executing one or more control algorithms. The control algorithms may include instructions that may be stored by the memory 220 for retrieval and execution by the processor 210. In some cases, the memory 220 may also store one or more tables (e.g., lookup tables) and may use the information in the tables and / or the information as described herein to perform various calculations and / or applications.

[0028] The processor 210 may be configured to execute the control algorithms serially or in parallel. However, in an example embodiment, the processor 210 may be configured to execute multiple control algorithms in parallel (e.g., simultaneously) and substantially in real time. The control algorithms may be configured to perform various calculations based on the received / generated information about the specific conditions of the vehicle components. Therefore, the control algorithm may perform various functions based on the received information and generate outputs to drive the control of the torque applied to the wheels of the vehicle 110 (individually or in pairs). The torque control module 130 itself may be a control algorithm, or may include a control algorithm in the form of a functional module (or submodule) that is configured to perform the specific functions for which they are configured to be associated with controlling the vehicle 110 in the manner described herein. Therefore, for example, the controller 140 may actually function as the torque control module 130 in response to executing the control algorithm. However, in other cases, the torque control module 130 may be a component or module of the controller 140, or a completely separate component (e.g., including its own corresponding processing circuit).

[0029] In an example embodiment, the torque control module 130 may include a turn enhancer or yaw generator 230 that defines a negative torque value 232 to be applied to an inside rear wheel 234 (e.g., via a braking system 236 of the vehicle 110) to generate enhanced yaw for the vehicle 110 during a turn. The yaw generator 230 may be configured to generate the negative torque value 232 only when a mode selection 240 has been made to place the vehicle 110 (e.g., via its controller 140) in a turn assist mode (or other similar mode) and when certain other qualifying conditions (e.g., triggering events or triggering conditions) have been met. For example, the yaw generator 230 may also receive inputs including a vehicle speed 242 and a steering wheel angle 244. The turn assist mode may, for example, only be operable below a certain speed or threshold speed (e.g., below 12 miles per hour (mph) or another suitable speed value). Furthermore, in some cases, the turn assist mode may be operable (and thus only the yaw generator 230 is active) only when the turn is of sufficient magnitude (at a low speed defined by a threshold value of the vehicle speed 242). For example, the yaw generator 230 may only operate when the steering wheel has been turned to a maximum degree (or a predetermined angle close to the maximum angle) in one direction or the other. Thus, in some cases, the steering wheel angle 244 and the vehicle speed 242 may be the only enabling factors or triggering criteria for the operation of the yaw generator 230. However, in other cases, the yaw generator 230 may generate the negative torque value 232 based on one or more of the vehicle speed 242 and the steering wheel angle 244. Thus, for example, a table of torque values ​​may be indexed to the corresponding values ​​of the vehicle speed 242 and / or the steering wheel angle 244 to determine the magnitude of the negative torque value 232.

[0030] In some embodiments, alternatively or additionally, the negative torque value 232 may be generated based on additional or other criteria. For example, in some cases, a slip table 250 may be provided to generate the slip value 252. The slip table 250 may include a series of output values ​​determined based on corresponding input values. Based on the corresponding input values, the slip table 250 may be referenced to determine the slip value 252. Figure 2 As shown in , slip table 250 may take into account vehicle speed 242 and / or steering wheel angle 244 in order to determine slip value 252. Slip value 252 itself may be defined as a value just below the peak tire friction coefficient (which may be referred to as tire μ). In such an example, if turn assist mode is selected, yaw generator 230 may use slip value 252 to define negative torque value 232 to be applied to inside rear wheel 234 if vehicle speed 242 is below a threshold speed (e.g., 12 mph) and the steering wheel is turned to a maximum angle for a given period of time (e.g., held in a locked state, indicating that the driver is providing steering torque to hold the wheel against the end stop for at least a given period of time).

[0031] Because applying a negative torque value 232 to the inside rear wheel 234 will increase the yaw rate of the vehicle 110 during the ongoing turn, the turning radius of the vehicle 110 can be reduced as desired. However, providing a negative torque value 232 (e.g., only via regenerative braking or applying friction brakes to the inside rear wheel 234) will tend to decelerate the vehicle 110 during the resulting turn, which the driver will feel, and thus make the turn feel less seamless. To generate a more seamless turn, an example embodiment may provide a positive torque value 260 to a propulsion system 262 of the vehicle 110 via a compensator 264. The compensator 264 may be configured to generate a feed-forward torque value to offset the negative torque value 232, thereby making the turn more seamless. The positive torque value 260 may be provided to the propulsion system 262 to, for example, apply power to a front axle or front wheel 266 of the vehicle 110. Thus, for example, front wheels 266 of vehicle 110 may pull vehicle 110 through a turn while inside rear wheel 234 has a negative torque applied thereto to increase the yaw rate that may be generated and thereby eliminate any noticeable speed changes during the turn while also increasing the turn rate.

[0032] In an example embodiment, compensator 264 may receive an input value indicating the magnitude of the negative torque actually applied at the inner rear wheel 234. For example, compensator 264 may receive an indication of the brake pressure 268 applied at the inner rear wheel 234. Therefore, the positive torque value 260 generated by compensator 264 may be proportional to the brake pressure 268 applied at the inner rear wheel 234. Therefore, positive torque value 260 and negative torque value 232 may not be set to equal values, but instead, for a given situation, positive torque value 260 may be set to tend to make the deceleration generated by negative torque value 232 less noticeable while still increasing the turning rate (e.g., via increasing the yaw rate of vehicle 110). However, in examples where each of front wheels 266 has a separate electric motor (e.g., in the case of some BEVs), the ratio may be set to one to one. Otherwise, for example, if the brake pressure is 1000 Nm, the magnitude of positive torque value 260 may be lower than 1000 Nm.

[0033] like Figure 2 As shown in FIG. 1 , a brake pedal 270 of the vehicle 110 may be used to provide a braking input to the braking system 236 (rather than to both wheels), and an accelerator pedal 272 may be used to provide a propulsion input to the propulsion system 262 of the vehicle 110. These inputs may be in addition to the inputs automatically provided by the torque control module 130 described herein. Thus, to the extent that the driver operates either or both of the brake pedal 270 and the accelerator pedal 272, the torque control module 130 may provide its automatic modifications to the positive and negative torques in an additive manner with the manual inputs while also responding to changes made via the driver's manual inputs.

[0034] Figure 3 An embodiment of a vehicle control system 300 is depicted, wherein the control system 300 may include a μ detection module 310. The μ detection module 310 may estimate the μ condition of a surface on which the vehicle 110 may operate when the turn assist feature is active and when the turn assist feature may be inactive. Thus, in some cases, the tire μ described above may be continuously calculated while the vehicle 110 is operated by the μ detection module 310, and thus the controller 140 may also know the μ estimate if any wheel has slipped in the past. In an example embodiment, the calculation of the tire μ may be an estimate of the tire μ based on several factors, rather than a direct measurement of the coefficient of friction. In this regard, it is assumed, for example, that the vehicle 110 is a BEV. Thus, the drive train 170 may include one or more electric motors that may be operably coupled to the μ detection module 310 or may include the μ detection module therein. The μ detection module 310 may estimate the coefficient of friction (i.e., μ) between the corresponding wheels of the wheels 180 of the vehicle 110 and the surface on which the vehicle 110 operates. The μ estimate of the example embodiment may be based on the magnitude of torque (positive or negative) delivered to a particular wheel via the driveline 170 or brakes (friction brakes or regenerative brakes) at the precise point in time when wheel slip may be detected at the particular wheel. In other words, the μ estimate may be a function of the torque applied to the wheel. Therefore, the μ detection module 310 may not directly measure the coefficient of friction of the driving surface, but may calculate the μ estimate based on known inputs to the wheel.

[0035] The μ detection module 310 may share the μ estimate with the controller 140, which, as discussed in detail above, may employ the turning assist feature by directly applying braking torque to the inside rear wheel of the vehicle 110 during a turn when a trigger condition for implementing the turning assist feature is detected. In some cases, the controller 140 may also automatically generate a blocking signal to block the operation of the turning assist feature in response to the μ detection module 310 estimating a minimum μ value that is less than a threshold μ value. This would indicate that one or more wheels 180 of the vehicle 110 may be operating on a slippery surface. In this regard, during low μ driving conditions (e.g., driving on a slippery surface, such as driving in snowy or icy conditions), it may not be advantageous for the operator 125 of the vehicle 110 to automatically engage the turning assist feature in response to detecting the trigger condition. As described above, the turning assist feature may temporarily apply power only to the front wheels 266, which may therefore disable any all-wheel drive capability of the vehicle 110, thereby effectively changing the vehicle 110 to temporary front-wheel drive. Importantly, all-wheel drive capability may be more beneficial to the operator 125 than the turn assist feature in low μ driving conditions, and therefore it may be desirable to automatically generate a blocking signal to block operation of the turn assist feature in response to the μ detection module 310 estimating a minimum μ value of the surface that is less than a threshold μ value (which may be indicative of a slippery driving surface).

[0036] As described above, the μ detection module 310 can estimate the μ condition of the surface on which the vehicle 110 can operate when the turn assist feature is active and when the turn assist feature is inactive. Therefore, the algorithm for detecting low μ conditions contained in the memory 220 of the controller 140 can be predictive and reactive: predictive in the sense that the turn assist feature may not be activated if a low μ condition is detected, and reactive in the sense that when a low μ condition is detected, if the turn assist feature is currently active, the turn assist feature can be deactivated or terminated. In some example embodiments, detecting a low μ condition can occur when the minimum μ value is less than a threshold μ value. In example embodiments, the threshold μ value can be predetermined and stored in the memory 220 of the controller 140. In some cases, the threshold μ value can be approximately 0.4, which can closely correspond to the μ values ​​associated with snow (approximately 0.3) and ice (approximately 0.1). Therefore, in response to the μ detection module 310 estimating that the minimum μ value is less than the threshold μ value, the use of the turn assist feature can be suppressed.

[0037] In various example embodiments, the minimum μ value may be defined differently. For example, in one embodiment, the minimum μ value may simply be the lowest value among the local μ estimates at each wheel 180 of the vehicle 110 collected by the μ detection module 310. Such an embodiment may assume that the entire vehicle 110 is on a uniform surface with the same or substantially similar coefficient of friction at each wheel, or that the vehicle 110 will be located on a surface with the same or substantially similar coefficient of friction at each wheel. This embodiment may be more conservative than other embodiments because the μ estimate at any wheel may be less than the threshold value so that the controller 140 generates a blocking signal to block the turn assist feature accordingly.

[0038] In another example embodiment, the μ detection module 310 may estimate a local μ value at each of the front wheels 266 of the vehicle 110, and the minimum μ value may be the lowest of the local μ values ​​at the front wheels 266. As described above, when the turn assist feature is active, the front axle may deliver power according to the demand of the operator 125, and thus the front wheels 266 may receive a higher torque than the rear wheels. In such cases, the front wheels 266 may be more likely to slip before the rear wheels, and if the front wheels slip, the controller 140 may generate a blocking signal to block the turn assist feature accordingly.

[0039] In other example embodiments, the μ detection module 310 may estimate a local μ value at each of the rear wheels of the vehicle, and the minimum μ value may be the lowest of the local μ values ​​of the rear wheels. In this regard, if one or both of the μ estimates for the rear wheels are below a threshold μ value, but none of the μ estimates for the front wheels are below a threshold μ value, the vehicle 110 may be passing through a section of the surface that may have a low μ condition. In such example embodiments, it may not be necessary to immediately block and / or deactivate the turn assist feature because the wheels may quickly recover higher μ conditions again. In this regard, the controller 140 may start a timer and monitor one or more specific wheels that detect a low μ estimate within a set amount of time. If the wheel recovers during the set amount of time, the turn assist feature may remain on and / or ready to be activated. If the wheel does not recover during the set amount of time, the turn assist feature may be blocked and / or deactivated.

[0040] Preventing the turn assist feature from fully activating may be accomplished by the controller 140 generating a blocking signal for the turn assist feature. In other words, if the turn assist feature is not already active when the μ detection module 310 estimates a minimum μ value that is below a threshold μ value, the blocking signal may not allow the turn assist feature to activate at all. In an example embodiment, the blocking signal may be an inhibit flag that may prevent activation of the turn assist feature as long as the inhibit flag is “true” or “in place” or “on.” In some cases, the blocking signal may remain on for a predetermined duration after estimating a minimum μ value that is below the threshold μ value. This ensures that the turn assist feature cannot be activated until a predetermined duration has passed, or until the minimum μ value increases to be greater than the threshold μ value.

[0041] Figure 4 A flow chart representing an example embodiment of the decisions made by the μ detection module 310 and the controller 140 is depicted. Figure 4 In an embodiment of the invention, once the vehicle 110 is "on", such as when actively driving or preparing to drive, the μ detection module 310 can calculate μ estimates, and the controller 140 can read them accordingly. If the minimum μ estimate is not below the threshold μ value, the controller 140 can take no action, nothing can inhibit the activation of the turn assist feature, and the controller 140 can continue to read μ estimates from the μ detection module 310. If the minimum μ estimate is below the threshold μ value, whether the turn assist feature is already active can determine the action taken by the controller 140. For example, if the turn assist feature is not already active, the controller 140 can generate the blocking signal discussed above and can maintain the blocking signal for a predetermined duration. Once the predetermined duration expires, nothing can inhibit the activation of the turn assist feature, and the controller 140 can continue to read μ estimates from the μ detection module 310 accordingly. However, if the turn assist feature is already active, the blocking signal can deactivate or terminate the turn assist feature, and thus the blocking signal can be maintained for a predetermined duration thereafter.

[0042] Figure 5 A flow chart representing an example embodiment of the decisions made by the μ detection module 310 and the controller 140 is also depicted. Figure 5In an embodiment of the invention, once the vehicle 110 is "on", such as when actively driving or preparing to drive, the μ detection module 310 can calculate the μ estimates and the controller 140 can read them accordingly. If the minimum μ estimate is not below the threshold μ value, the controller 140 can take no action, but before allowing the turn assist feature to activate, the controller 140 can read the μ estimates from the rear wheels. If the minimum rear μ estimate is also not below the threshold μ value, there is nothing to inhibit the turn assist feature from activating, and the controller 140 can continue to read the μ estimates from the μ detection module 310. However, if the minimum rear μ estimate is below the threshold μ value, the controller can start the timer discussed above and monitor the rear wheels for a set amount of time to see if they resume a higher μ condition. If the rear wheels do resume a higher μ condition, no action is taken and there is nothing to inhibit the turn assist feature. If the rear wheels do not resume a higher μ condition, a blocking signal can be generated.

[0043] Similar to Figure 4 In the embodiment of Figure 5 In an embodiment of the invention, if the minimum μ estimate value is below the threshold μ value, whether the turn assist feature is already active may determine the action taken by the controller 140. For example, if the turn assist feature is not already active, the controller 140 may generate the blocking signal discussed above and may maintain the blocking signal for a predetermined duration. Once the predetermined duration expires, there is nothing to inhibit the turn assist feature from activating, and the controller 140 may continue to read μ estimates from the μ detection module 310 accordingly. However, if the turn assist feature is already active, the blocking signal may deactivate or terminate the turn assist feature, and thus may maintain the blocking signal for a predetermined duration thereafter.

[0044] Figure 6 A block diagram of an example method for providing automatic application of a turning radius reduction in a driver assist mode is shown. The method may include estimating a μ condition of a surface on which the vehicle is operating via a μ detection module at operation 600. The method may also include receiving a mode selection selecting a turn assist mode at operation 610, and receiving steering wheel angle and vehicle speed information at operation 620 to determine whether a trigger condition for implementing a turn assist feature may be met during a turn. At operation 630, in response to detecting the trigger condition for implementing the turn assist feature, the method may also include applying a negative torque to the inside rear wheel, and at operation 640, automatically generating a blocking signal to block operation of the turn assist feature in response to the μ detection module estimating a minimum μ value of the surface that is less than a threshold μ value.

[0045] Thus, example embodiments may also include a vehicle control system that may include: a mode selector including at least a turn assist mode that may be selected by an operator of the vehicle to activate a turn assist feature; a controller for engaging the turn assist feature by directly applying a braking torque to an inside rear wheel of the vehicle during a turn when a triggering condition for implementing the turn assist feature may be detected; and a μ detection module for estimating a μ condition of a surface on which the vehicle may operate. The controller may also automatically generate a blocking signal to block operation of the turn assist feature in response to the μ detection module estimating a minimum μ value of the surface that may be less than a threshold μ value.

[0046] The systems of some embodiments may include additional features, modifications, extensions, etc. to achieve further goals or enhance the performance of the system. Additional features, modifications, extensions, etc. may be added in any combination with each other. The following is a list of various additional features, modifications, and extensions, which may be added individually or in any combination with each other. For example, the μ detection module may continuously estimate the minimum μ value of the surface on which the vehicle can operate when the turn assist feature can be active and when the turn assist feature can be inactive. In an example embodiment, the blocking signal may be configured to deactivate the turn assist feature in response to the minimum μ value being lower than the threshold μ value when the turn assist feature can be active. In some cases, the blocking signal may be configured to prevent the activation of the turn assist feature in response to the minimum μ value being lower than the threshold μ value before the turn assist feature can be active. In an example embodiment, after estimating the minimum μ value that may be lower than the threshold μ value, the blocking signal may remain on for a predetermined duration so that the turn assist feature cannot be activated before the predetermined duration has passed. In some cases, the μ detection module may estimate local μ values ​​at all wheels of the vehicle, and the minimum μ value may be the lowest value of the local μ values. In an example embodiment, the μ detection module may estimate local μ values ​​at the front wheels of the vehicle, and the minimum μ value may be the lowest value of the local μ values. In some cases, the μ detection module may estimate local μ values ​​at the rear wheels of the vehicle, and the minimum μ value may be the lowest value of the local μ values. In an example embodiment, in response to the minimum μ value being lower than the threshold μ value, the blocking signal does not block the operation of the turn assist feature until the rear wheels are monitored for a set amount of time. In some cases, the triggering condition may include detecting that the steering wheel angle is at a maximum angle corresponding to the rotation limit of the steering wheel, and detecting that the vehicle speed is lower than a threshold speed.

[0047] In another example embodiment, a method of automatically controlling application of a turn assist feature in a vehicle is provided. The method may include estimating, via a μ detection module, a μ condition of a surface on which the vehicle may operate, receiving a mode selection selecting a turn assist mode, receiving steering wheel angle and vehicle speed information to determine whether a trigger condition for implementing the turn assist feature may be satisfied during a turn, applying a negative torque to an inside rear wheel in response to detecting the trigger condition for implementing the turn assist feature, and automatically generating a blocking signal to block operation of the turn assist feature in response to the μ detection module estimating a minimum μ value of the surface that may be less than a threshold μ value.

[0048] A person skilled in the art of the invention who has benefited from the teachings presented in the foregoing description and the associated drawings will think of many modifications and other embodiments of the invention set forth herein. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the foregoing description and the associated drawings describe example embodiments in the context of certain exemplary combinations of elements and / or functions, it should be understood that alternative embodiments may provide different combinations of elements and / or functions without departing from the scope of the appended claims. In this regard, for example, as may be set forth in some of the appended claims, combinations of elements and / or functions different from those explicitly described above are also contemplated. Where advantages, benefits, or solutions to problems are described herein, it should be understood that such advantages, benefits, and / or solutions may be applicable to some example embodiments, but not necessarily to all example embodiments. Therefore, any advantages, benefits, or solutions described herein should not be considered to be critical, necessary, or essential to all embodiments or embodiments claimed herein. Although specific terms are employed herein, they are used only in a general and descriptive sense, not for the purpose of limitation.

[0049] According to the present invention, a vehicle control system is provided, which has: a mode selector, the mode selector including at least a turning assist mode, the turning assist mode being selectable by an operator of the vehicle to activate a turning assist feature; a controller, the controller being used to employ the turning assist feature by directly applying a braking torque to an inner rear wheel of the vehicle during a turn when a trigger condition for implementing the turning assist feature is detected; and a μ detection module, the μ detection module being used to estimate a μ condition of a surface on which the vehicle operates, wherein the controller also automatically generates a blocking signal to block operation of the turning assist feature in response to the μ detection module estimating a minimum μ value of the surface that is less than a threshold μ value.

[0050] According to an embodiment, the μ detection module continuously estimates the minimum μ value of the surface on which the vehicle operates when the turn assist feature is active and when the turn assist feature is inactive.

[0051] According to an embodiment, the blocking signal is configured to deactivate the turn assist feature in response to the minimum μ value being below a threshold μ value when the turn assist feature is active.

[0052] According to an embodiment, the blocking signal is configured to prevent activation of the turn assist feature in response to the minimum μ value being below the threshold μ value before the turn assist feature is active.

[0053] According to an embodiment, after estimating the minimum μ value below the threshold μ value, the blocking signal remains on for a predetermined duration such that the turn assist feature cannot be activated before the predetermined duration has elapsed.

[0054] According to an embodiment, the μ detection module estimates local μ values ​​at all wheels of the vehicle, and the minimum μ value is the lowest value among the local μ values.

[0055] According to an embodiment, the μ detection module estimates local μ values ​​at the front wheels of the vehicle, and the minimum μ value is the lowest value among the local μ values.

[0056] According to an embodiment, the μ detection module estimates local μ values ​​at rear wheels of the vehicle, and the minimum μ value is a lowest value among the local μ values.

[0057] According to an embodiment, in response to the minimum μ value being below the threshold μ value, the blocking signal blocks operation of the turn assist feature until after monitoring the rear wheels for a set amount of time.

[0058] According to an embodiment, the triggering conditions include detecting that the steering wheel angle is at a maximum angle corresponding to a rotation limit of the steering wheel, and detecting that the vehicle speed is below a threshold speed.

[0059] According to the present invention, a method for automatically controlling the application of a turning assist feature in a vehicle includes: estimating a μ condition of a surface on which the vehicle operates via a μ detection module; receiving a mode selection that selects a turning assist mode; receiving steering wheel angle and vehicle speed information to determine whether a trigger condition for implementing the turning assist feature is met during turning; in response to detecting the trigger condition for implementing the turning assist feature, applying a negative torque to an inner rear wheel; and automatically generating a blocking signal to block operation of the turning assist feature in response to the μ detection module estimating a minimum μ value of the surface that is less than a threshold μ value.

[0060] In one aspect of the invention, the μ detection module continuously estimates the minimum μ value of the surface on which the vehicle operates when the turn assist feature is active and when the turn assist feature is inactive.

[0061] In one aspect of the invention, the blocking signal is configured to deactivate the turn assist feature in response to the minimum μ value being below a threshold μ value when the turn assist feature is active.

[0062] In one aspect of the invention, the blocking signal is configured to prevent activation of the turn assist feature in response to the minimum μ value being below the threshold μ value before the turn assist feature is active.

[0063] In one aspect of the invention, after evaluating said minimum μ value below said threshold μ value, said blocking signal remains on for a predetermined duration such that said turn assist feature cannot be activated before said predetermined duration has elapsed.

[0064] In one aspect of the present invention, the μ detection module estimates local μ values ​​at all wheels of the vehicle, and the minimum μ value is the lowest value among the local μ values.

[0065] In one aspect of the present invention, the μ detection module estimates local μ values ​​at front wheels of the vehicle, and the minimum μ value is a lowest value among the local μ values.

[0066] In one aspect of the present invention, the μ detection module estimates local μ values ​​at rear wheels of the vehicle, and the minimum μ value is a lowest value among the local μ values.

[0067] In one aspect of the invention, in response to said minimum μ value being below said threshold μ value, said blocking signal blocks operation of said turn assist feature until after monitoring said rear wheels for a set amount of time.

[0068] In one aspect of the invention, the triggering condition includes detecting that the steering wheel angle is at a maximum angle corresponding to a rotation limit of the steering wheel, and detecting that the vehicle speed is below a threshold speed.

Claims

1. A vehicle control system, the system comprising: a mode selector including at least a turn assist mode selectable by an operator of the vehicle to activate a turn assist feature; a controller for engaging the turn assist feature by directly applying braking torque to an inside rear wheel of the vehicle during a turn upon detecting a triggering condition for implementing the turn assist feature; and a μ detection module for estimating a μ condition of a surface on which the vehicle operates, Wherein the controller is further responsive to the μ detection module estimating a minimum μ value of the surface that is less than a threshold μ value to automatically generate a blocking signal to block operation of the turn assist feature. 2 . The system of claim 1 , wherein the μ detection module continuously estimates the minimum μ value for the surface on which the vehicle operates when the turn assist feature is active and when the turn assist feature is inactive.

3. The system of claim 1 , wherein the blocking signal is configured to terminate the turn assist feature in response to the minimum μ value being below the threshold μ value while the turn assist feature is active, or to prevent activation of the turn assist feature in response to the minimum μ value being below the threshold μ value before the turn assist feature is active.

4. The system of claim 3, wherein the blocking signal remains on for a predetermined duration after the minimum μ value is estimated to be below the threshold μ value, such that the turn assist feature cannot be activated until the predetermined duration has elapsed.

5. The system of claim 3, wherein the μ detection module estimates local μ values ​​at all wheels of the vehicle, at the front wheels of the vehicle, or at the rear wheels of the vehicle, and the minimum μ value is the lowest value among the local μ values. 6 . The system of claim 5 , wherein in response to the minimum μ value being below the threshold μ value, the blocking signal blocks operation of the turn assist feature until after monitoring the rear wheels for a set amount of time. 7 . The system of claim 1 , wherein the triggering condition includes detecting that the steering wheel angle is at a maximum angle corresponding to a rotation limit of the steering wheel and detecting that the vehicle speed is below a threshold speed.

8. A method of automatically controlling application of a turn assist feature in a vehicle, the method comprising: estimating, via a μ detection module, a μ condition of a surface on which the vehicle operates; receiving a mode selection selecting a turn assist mode; receiving steering wheel angle and vehicle speed information to determine whether a trigger condition for implementing the turn assist feature is satisfied during a turn; In response to detecting the trigger condition for implementing the turn assist feature, applying a negative torque to the inside rear wheel; and A blocking signal is automatically generated to block operation of the turn assist feature in response to the μ detection module estimating a minimum μ value of the surface that is less than a threshold μ value. 9 . The method of claim 8 , wherein the μ detection module continuously estimates the minimum μ value for the surface on which the vehicle operates when the turn assist feature is active and when the turn assist feature is inactive.

10. The method of claim 8, wherein the blocking signal is configured to terminate the turn assist feature in response to the minimum μ value being below the threshold μ value while the turn assist feature is active, or to prevent activation of the turn assist feature in response to the minimum μ value being below the threshold μ value before the turn assist feature is active.

11. The method of claim 10, wherein after estimating the minimum μ value below the threshold μ value, the blocking signal remains on for a predetermined duration such that the turn assist feature cannot be activated before the predetermined duration has elapsed.

12. The method of claim 10, wherein the μ detection module estimates local μ values ​​at all wheels of the vehicle, at the front wheels of the vehicle, or at the rear wheels of the vehicle, and the minimum μ value is the lowest value among the local μ values.

13. The method of claim 12, wherein in response to the minimum μ value being below the threshold μ value, the blocking signal blocks operation of the turn assist feature until after monitoring the rear wheels for a set amount of time.

14. The method of claim 8, wherein the triggering conditions include detecting that the steering wheel angle is at a maximum angle corresponding to a rotation limit of the steering wheel and detecting that the vehicle speed is below a threshold speed.

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