Vehicle stability learning for brake steering and MU estimation

Abstract

A number of variations may include a method that may include modifying at least one braking or powertrain torque or force for one or more wheels of a vehicle in real time to increase lateral stability during braking steering functionality.

Description

Field of Technology

[0001] The field of the present disclosure generally relates to steering, braking, and powertrain systems. Background Art

[0002] In some cases, braking steer (BtS) braking and powertrain commands may cause vehicle instability or unexpected vehicle oversteering, especially in low surface friction coefficient (surface Mu) driving situations. Current vehicle instability or unexpected vehicle oversteering mitigation is reactive and temporary.

[0003] In addition, it is difficult for a vehicle to accurately estimate and sense surface mu. Surface Mu information can be used to improve various vehicle functions. Summary of the Invention

[0004] Multiple variations may include a method that may include modifying at least one braking or powertrain torque or force of one or more roadwheels of a vehicle in real time to increase lateral stability during a braking steer function.

[0005] Multiple variations may include a method that may include increasing, decreasing, or scaling at least one of an electronic braking system braking command or a powertrain system command during a braking steer event. This can prevent vehicle instability or unexpected vehicle oversteering.

[0006] Vehicle instability may lead to a complete loss of vehicle control or pose a safety hazard. Multiple variations may include a method that may reduce the likelihood of losing vehicle control by modifying at least one of the braking steer braking or powertrain commands based on multiple calculated, measured, or observed stability indicators. This can not only improve vehicle safety but also utilize braking steer functionality to improve overall vehicle controllability.

[0007] From the detailed description provided below, other illustrative variations within the scope of the present invention will become apparent. It should be understood that the detailed description and specific examples, while disclosing variations of the present invention, are only for illustrative purposes and are not intended to limit the scope of the present invention. Brief Description of the Drawings

[0008] Selected examples of variations within the scope of the present invention will be more fully understood from the detailed description and the drawings, in which:

[0009] Figure 1 Illustrates a method according to multiple variations;

[0010] Figure 2Depicting illustrative variations of a vehicle having a steer-by-wire system, where the vehicle also has the ability to perform brake steer, and the ability to modify brake commands and powertrain commands; and

[0011] Figure 3 Depicting illustrative variations of a vehicle having a connected power steering system, where the vehicle also has the ability to perform brake steer, and the ability to modify brake commands and powertrain commands.

[0012] The figures are not necessarily to scale, and for clarity and conciseness, some features and some views of the figures may be enlarged, either to scale or schematically, and should not be considered limiting. Detailed Description

[0013] The following description of the variations is illustrative in nature and is in no way intended to limit the scope of the invention, its application, or its use.

[0014] Multiple variations may include systems that include one or more physical components described herein and may be configured to perform one or more actions of the methods described herein. Multiple variations may include methods that include one or more actions or steps described herein, or provide or implement one or more of the functionalities described herein. Multiple variations may include non-transitory computer-readable media having instructions stored thereon that may be executed by an electronic processor to implement the functionalities described herein. Multiple variations may include an electronic controller that includes an electronic processor, a non-transitory computer-readable media having instructions stored thereon that may be executed by the electronic processor to implement the functionalities described herein, and the non-transitory computer-readable media may include a memory for storing data collected from vehicle sensors or data generated by executing the instructions. In multiple variations, the instructions, when executed by an electronic process, implement the functionality of vehicle stability learning for brake steer and / or Mu estimation, which can help prevent BtS from causing instability or unexpected vehicle oversteer in an active, reactive, and non-transitory manner and may be adapted to driving conditions and driving event history. The instructions implementing vehicle stability learning for brake steer and Mu estimation functionality may also provide surface Mu estimation using a unique learning method.

[0015] When executed by an electronic process, the instruction can perform the following functions: receiving a vehicle dynamics data input, which can be from one or more vehicle sensors. The vehicle dynamics data can include but is not limited to vehicle speed, vehicle yaw rate, vehicle acceleration, steering wheel angle, and wheel speed. When executed by an electronic process, the instruction can perform the following functions: receiving or calculating one or more stability indicators and thresholds. When executed by an electronic process, the instruction can perform the following functions: using the stability indicator duration and magnitude to determine whether an instability event is occurring.

[0016] If or when an instability event occurs, when executed by an electronic process, the instruction can perform the following functions: calculating a new or first BtS modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned BtS modification, or the previously stored stability memory data, which can include but is not limited to a modification that reduces the BtS command. As used herein, reducing the BtS command means decreasing, reducing, subtracting, multiplying by a scalar between 0 and 1, or dividing by a positive scalar greater than 1. As used herein, the term "current" refers to the current time when the event is occurring, such as but not limited to the current time when the instability event is occurring. As used herein, the term "first" does not necessarily mean first in time. As used herein, the term "second" does not necessarily mean second in time. When executed by an electronic process, the instruction can also perform the following functions: estimating a new maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input. When executed by an electronic process, the instruction can perform the following functions: calculating a new or first learned Mu estimate using the new estimated maximum achievable vehicle acceleration, the previous estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previous estimated Mu value.

[0017] If or when an instability event does not occur, the instructions can perform the following functions when executed by an electronic process: Monitor the received vehicle dynamics data input to determine whether vehicle maneuvers exceed the currently estimated maximum achievable vehicle acceleration. If the vehicle acceleration exceeds the currently estimated maximum achievable vehicle acceleration and an instability event does not occur, the instructions can perform the following functions when executed by an electronic process: Calculate a new BtS modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned BtS modification, or the previously stored stability memory data, which can include but is not limited to increasing the modification of the BtS command. The instructions can perform the following functions when executed by an electronic process: Estimate a new maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input. The instructions can perform the following functions when executed by an electronic process: Calculate a new learned Mu estimate using the new estimated maximum achievable vehicle acceleration, the previous estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previous estimated Mu value.

[0018] The instructions can perform the following functions when executed by an electronic process: Use the new BtS modification to change at least one of the BtS brake or powertrain commands in an active, reactive, and non-transitory manner. This can occur before or after the activation of the BtS function. The instructions can perform the following functions when executed by an electronic process: Use the new, learned Mu estimate to enhance the BtS functionality. The instructions can perform the following functions when executed by an electronic process: Transmit the new, learned Mu estimate to other vehicle functions.

[0019] The instructions can perform at least one of the following functions when executed by an electronic process: Improve vehicle controllability and safety during maneuvers that may cause vehicle instability; Improve vehicle stability with a more non-transitory strategy during BtS compared to previous methods; Be more adaptable than alternative BtS stability methods because it can change its output based on the driving event history; Establish BtS vehicle stability protection before BtS activation, which is active and earlier and faster than other BtS stability methods; or Provide a surface mu estimate that can be used to create smarter, more accurate, and more precise vehicle functions (including BtS) and vehicle dynamics models.

[0020] Vehicles typically include a steering system, a braking system, and a powertrain system. The steering system can be a connected steering system with power steering (a steering system having a mechanical connection between the handwheel and the rack) or a steer-by-wire system (a steering system having no mechanical connection between the handwheel and the rack). The braking system can include various components for stopping the movement of the vehicle, including friction brakes and electric brakes. The powertrain can include various components for propulsion (such as an internal combustion engine or an electric motor), as well as various components for transferring torque, force, or pressure from the propulsion system to individual tires (including transmissions, differentials, and torque vectoring differentials). Commands sent to the braking or powertrain systems can include commanded torque, force, throttle or pedal position, current, voltage, pressure, etc. The load can include torque, force, or pressure. The steering, braking, or powertrain systems can include electronics that allow them to send or receive signals and commands, convert received commands into loads within or generated by the system, and ultimately into loads at the tires. The driver of the vehicle controls the movement of the vehicle and can include a human driver or an automated driver. Systems such as the steering system can fail, which can include total or partial failure or degradation.

[0021] Braking Steering (BtS) is a system that can provide braking and powertrain commands to the brakes and powertrain systems based on driver intent information in the event of a steering system failure to assist the driver with lateral control. This can be applied to vehicles having an EPS connected steering system or a steer-by-wire system. Braking Steering can be applied to vehicles having a human or automated driver. Driver intent can be determined from steering system signals (such as handwheel angle or handwheel torque), or alternatively can be determined indirectly via vehicle inputs (such as vehicle lateral acceleration, yaw rate, and / or vehicle speed). BtS takes these driver intent inputs and outputs specific brake and powertrain commands to individual tires to generate loads that can assist the driver with lateral control of the vehicle. Some examples of BtS improvements include, but are not limited to, improved vehicle handling, reduced steering effort when the connected EPS system has failed, or enabling lateral control of a steer-by-wire vehicle when the road wheel actuator has failed, or enabling lateral control of an automated vehicle having a connected EPS or SbW steering system when the steering system has failed.

[0022] In certain driving scenarios activated by BtS, BtS may cause unexpected vehicle oversteering or excessive vehicle yaw rate. An example of such a scenario may occur when the driver's maneuvers while turning cause the tires to exceed the surface friction limit. To prevent unexpected vehicle oversteering or excessive vehicle yaw rate caused by BtS in an active, reactive, and non-transitory manner, vehicle stability learning for brake steer and Mu estimation instructions or algorithms is developed.

[0023] The instructions, when executed by an electronic process, can perform the following functions: vehicle stability learning for brake steer and Mu estimation, and can receive vehicle dynamics data inputs including but not limited to vehicle speed, vehicle yaw rate, vehicle acceleration, steering wheel angle, and wheel speed.

[0024] The instructions, when executed by an electronic process, can perform the following functions: receive or calculate one or more stability indicators. The calculated stability indicators may include yaw rate error. The yaw rate error can be calculated by comparing the estimated or predicted yaw rate with the measured vehicle yaw rate. The estimated yaw rate can be calculated based on lateral acceleration and vehicle speed or steering wheel angle and vehicle speed or individual wheel speeds. Another calculated stability indicator may include differential wheel slip. The differential wheel slip can be calculated based on individual wheel speeds and vehicle speed or individual wheel speeds and the longitudinal speed of the wheel. The received stability indicators may include received yaw rate error, received differential wheel slip, surface mu estimation, or activation flags from external systems (including but not limited to electronic stability control (ESC) activation, anti-lock braking system (ABS) activation, traction control system (TCS) activation, or electronic brake force distribution (EBD) activation).

[0025] The instructions, when executed by an electronic process, can perform the following functions: vehicle stability learning for braking steering, and the Mu estimation can compare the calculated or received stability indicator with a learned stability indicator threshold range. The learned stability indicator threshold range can depend on at least one of vehicle dynamics data input or the stability indicator magnitude (if applicable). The stability indicator threshold range can also consist of constants. If the stability indicator is outside its acceptable learned stability indicator threshold range for a duration exceeding a duration threshold, the executed instructions can set an instability detection active flag. The duration threshold can be a constant, can depend on the magnitude of stability, or can depend on vehicle dynamics data input, such as speed. When the stability indicator is within its acceptable learned stability indicator threshold range, or when the stability indicator is outside the acceptable learned stability indicator threshold range for a duration less than the duration threshold, the executed instructions can set an instability detection inactive flag. The instability detection active flag can indicate that an instability event is occurring. The instability detection inactive flag can indicate that an instability event is not occurring.

[0026] If the instability detection activity flag is set, the executed instructions can use at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned BtS modification, a counter, or the previously stored stability memory data to calculate a new BtS modification, which can include a modification that reduces the BtS command. Additionally, the instructions can perform the following functions when executed by an electronic process: store the stability memory data into memory when the instability detection activity flag is set. The vehicle dynamics data input can include vehicle speed, vehicle yaw rate, vehicle acceleration, steering wheel angle, or wheel speed. The current Mu estimate can include the most recent surface Mu estimate of the executed instructions, a programmed initial value, or a saved value from a previous critical period. The current learned BtS modification can include the most recent modifier value (calculated by the instructions when executed by an electronic process), a programmed initial value, or a saved value from a previous critical period. The stability memory data can include vehicle dynamics data values, a timestamp, a duration, a count, a stability indicator magnitude, a stability indicator duration, a previous BtS command modifier value, or a previous Mu estimate. The new BtS modification can be implemented by various means, including but not limited to a command scalar, an offset, a look-up table, a counter, or other numerical calculations. These modifications can depend on the stability indicator magnitude, duration, or the vehicle dynamics data input (such as vehicle speed, vehicle yaw rate, or vehicle acceleration). The newly calculated BtS modification can be applied until another new BtS modification is calculated, so the modification can be ready to be applied before BtS activation, during BtS activation, during a critical period, or during a subsequent critical period.

[0027] If the instability detection activity flag is set, the instructions can perform the following functions when executed by an electronic process: estimate a new maximum achievable vehicle acceleration based on the received vehicle dynamics signal. The maximum value can be based on the vehicle yaw rate, vehicle speed, vehicle acceleration, steering wheel angle, or a combination of the vehicle dynamics signals listed above. The new maximum value can be calculated by storing the vehicle signal value and timestamp as stability memory data into memory when the instability detection activity flag is set. The stored values can be averaged, weighted averaged, blended, or processed in some way to calculate the new estimated maximum achievable vehicle acceleration, which can be stored into memory.

[0028] If the instability detection active flag is set, then the instruction can perform the following functions when executed by an electronic process: Estimate a new surface mu estimate using at least one of vehicle dynamics calculations and new estimated maximum achievable vehicle acceleration or stability memory data. The calculation can include a vehicle model, a weighting function, data correlation, or some combination of the above. The vehicle model can include, but is not limited to, a two-track model, a bicycle model, or a point model.

[0029] If the instability detection inactive flag is set, then the instruction can perform the following functions when executed by an electronic process: Monitor the received vehicle dynamics data input to determine if the current vehicle acceleration exceeds the estimated maximum achievable vehicle acceleration. If the instability detection inactive flag is set and the estimated maximum achievable vehicle acceleration magnitude is not exceeded for a duration exceeding a duration threshold, the instruction being executed can leave its output unchanged. If the instability detection inactive flag is set and the estimated maximum achievable vehicle acceleration magnitude is exceeded for a duration exceeding the duration threshold, then the instruction can perform the following functions when executed by an electronic process: Calculate a new BtS modification using at least one of the current vehicle dynamics signal, the current mu estimate, the current learned BtS modification, a counter, or previously stored stability memory data, the new BtS modification can include a modification that increases the BtS command. The duration threshold can be a constant, can depend on the magnitude of stability, or can depend on the vehicle dynamics data input, such as speed. Additionally, the instruction can perform the following functions when executed by an electronic process: Store the stability memory data into memory when the instability detection inactive flag is set and the estimated maximum achievable vehicle acceleration is exceeded. The new BtS modification can be implemented by various means (including but not limited to a command scalar, an offset, a look-up table, a counter, or other numerical calculations). These modifications can depend on the stability indicator magnitude, duration, or vehicle dynamics data input (such as vehicle speed, vehicle yaw rate, or vehicle acceleration). The new BtS modification can be applied until another new BtS modification is calculated, and thus can be applied before BtS activation, during BtS activation, during a critical period, or during a subsequent critical period.

[0030] If the instability detection inactive flag is set and the estimated maximum achievable vehicle acceleration is exceeded, the instructions, when executed by an electronic process, can perform the following functions: Estimate a new maximum achievable vehicle acceleration based on the received vehicle dynamics signal. The new maximum value can be based on a combination of vehicle yaw rate, vehicle acceleration, steering wheel angle, or previous vehicle dynamics signals. The new maximum value can be calculated by storing the vehicle signal values and timestamps as stability memory data into a memory when the instability detection inactive flag is set and the estimated maximum achievable vehicle acceleration is exceeded. The stored values can be combined in some way to calculate a new estimated maximum achievable vehicle acceleration, which is then stored into the memory. As used herein, combining means switching, averaging, weighted averaging, or filtering.

[0031] If the instability detection inactive flag is set and the maximum achievable vehicle acceleration value is exceeded, the instructions, when executed by an electronic process, can perform the following functions: Estimate a new surface Mu estimate using the new estimated maximum achievable vehicle acceleration, previous estimated Mu value, and vehicle dynamics calculations. The calculations can include a dynamic vehicle model, weighting function, data correlation, or some combination of the above.

[0032] The instructions, when executed by an electronic process, can perform the following functions: Use the new BtS modification to change at least one of the BtS brake or powertrain commands in an active, reactive, or non-transitory manner. As used herein, the term "modification" can include increasing or decreasing the original unmodified value in any way, including adding or subtracting an offset, or multiplying or dividing by a ratio or scalar. The change can be applied until another new BtS modification is calculated, so the modification can be applied before BtS activation, during BtS activation, during a critical period, or during a subsequent critical period. The change is intended to keep the BtS commands within a safe range such that the BtS will not cause vehicle instability or vehicle oversteering. If applicable, the non-transitory BtS command modification can occur simultaneously with other transitory BtS command modification methods not described herein.

[0033] The instructions, when executed by an electronic process, can perform the following functions: Use new estimated surface Mu data to enhance BtS functionality by incorporating mu estimation information into the BtS command calculation. The BtS function can also provide a flag to downstream BtS functions to indicate that BtS should switch to an alternative BtS control mode or method more suitable for estimating surface Mu. The instructions, when executed by an electronic process, can perform the following function: Transmit the new estimated surface Mu data to other vehicle functions. For example, if the vehicle has a Mu fusion function that estimates surface Mu from different sources, the BtS Mu estimate can help improve the quality of the Mu fusion estimate. The Mu fusion function can use switching, averaging, weighted averaging, or filtering of Mu data or other data. The Mu estimate can also be used by other functions (such as dashboard warnings, steering functions, braking functions, propulsion functions, or ADAS functions) to improve performance and vehicle dynamics model accuracy.

[0034] Figure 1 Illustrated is a method for creating a new BTS modification when an instability event is occurring. The method can include using an electronic controller, including: Receiving vehicle dynamics data input 150; Receiving or calculating one or more stability indicators and thresholds 152; Using the stability indicator duration and magnitude to determine if an instability event is occurring 154; If an instability event is occurring, calculating a first braking and steering modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned braking and steering modification, or the previously stored stability memory data 156.

[0035] Figure 2 Illustrated is a vehicle having steer-by-wire functionality and a system for implementing the methods described herein. Figure 3 Illustrated is a vehicle having a mechanical steering linkage and a system for implementing the methods described herein. Assuming Figure 2 the vehicle in Figure 3 maintains steer-by-wire functionality, and Figure 2 and Figure 3 the vehicle in

[0036] Figure 2Illustrative variations depicting various parts of a vehicle equipped with hardware sufficient to implement at least some of the systems and methods described herein. All sensors depicted in the illustrative variations are illustrative, so the sensed inputs can come from various other vehicle locations or vehicle sensors as long as they provide similar sensing functionality. Vehicle 750 may include an electronic controller 712 configured and arranged to provide brake steer functionality in vehicle 750. Controller 712 may be operatively communicable with a steer-by-wire system 715 and an electronic brake system 716. The steer-by-wire system 715 may consist of a steering wheel actuator 746 and a road wheel actuator 714. The steer-by-wire system 715 may be configured and arranged to turn at least one road wheel 742. The electronic brake system 716 may apply a braking force or braking torque 720 to a determined appropriate road wheel 742. A driver may use a steering wheel 744 including at least one steering wheel actuator 746 to provide driver input 734 for lateral movement and send a steering command to the steer-by-wire system 715 and the road wheel actuator 714. The electronic brake system 716 may be operatively communicable with the controller 712 and a driver brake input system 752, such as a brake pedal system, to receive driver brake input. According to some variations, the steering wheel actuator 746 may be operatively communicable with the controller 712, the steer-by-wire road wheel actuator 714, or the electronic brake system 716. In some variations, the steering wheel actuator 746 may be disconnected from or in a fault state 748 with the steer-by-wire road wheel actuator 714 or unable to communicate with the steer-by-wire road wheel actuator 714. In such variations, the steering wheel actuator 746 may pass the steering command to the controller 712, which may receive steer-by-wire system 715 health state information. In the case where the controller 712 has received steer-by-wire system 715 information indicating a fault 748 in the steer-by-wire system 715 or a fault in the road wheel actuator 714, the controller 712 may convert the steering command from the steering wheel actuator 746 into a braking force or braking torque command to be passed to the electronic brake system 716. The electronic brake system 716 may apply the braking force or braking torque 720 to a determined appropriate road wheel 742 to effect lateral movement of the vehicle, thereby acting as the input 734 by the driver via the steering wheel 744. The controller 712 may also send a powertrain command to the powertrain system 708. The controller 712 and any other controllers (e.g., controller 768) may be provided to implement one or more of the functions described herein and may include a processor 760, a memory 762, where instructions 764 stored in the memory 762 may be executed by the processor 760.

[0037] Now refer to Figure 3, showing an illustrative variant of a vehicle equipped with hardware that allows the vehicle to implement at least some of the methods disclosed herein. All sensors depicted in the illustrative variant are illustrative, so the sensed inputs can come from various other vehicle locations or vehicle sensors as long as they provide similar sensing functionality. Vehicle 801 can be equipped with road wheels 802 and a steering wheel 803 that is used to turn the road wheels 802 via a pinion 804 that engages a rack 805, which is constructed and arranged to turn the road wheels 802. In the illustrative variant shown, the steering wheel 803 can be equipped with a steering wheel torque sensor 806 and a steering wheel angle sensor 807 such that any rotation of the steering wheel can generate sensor data that can be transmitted to or accessed by a controller 808. The controller 808 can provide all of the other functionality described herein, including brake steering, brake steering stability, brake steering stability learning, steer-by-wire control, powertrain control, brake control, controlling vehicle systems, or one or more other controllers can be provided to do the same. Although in this illustrative variant, the controller 808 is shown as being on the vehicle, the controller can also be located somewhere remote from the vehicle and communicate wirelessly via sensors or the vehicle. The pinion 804 can be equipped with a pinion torque sensor 809 such that any rotation of the pinion can be observed by or transmitted to the controller 808 and utilized by the methods described herein. In the illustrative variant shown, the rack 805 can be equipped with a rack force sensor 810 such that any rack force detected during driving can be observed by or transmitted to the controller 808 and utilized by the methods described herein. The vehicle can have a steering shaft 814 that connects the steering wheel or steering interface 803 to the pinion 804. An electric power steering assist or hydraulic power steering device 836 can be connected to the shaft 814 to assist the driver in steering the road wheels of the vehicle by reducing the force or torque that the driver would otherwise need to apply to the steering wheel or steering interface 803 in the absence of the power steering device 836. Also shown in this illustrative variant, road wheels 802 can be equipped with road wheel sensors such that any road wheel data detected during driving can be observed by or transmitted to the controller 808 and utilized by the methods described herein. Additionally, in the illustrative variant shown, brakes 812 are located near the road wheels 802.The controller 808 and any other controller (such as controller 818) can be provided to perform one or more functions described herein, and can include a processor 820, a memory 822, where instructions 824 stored in the memory 822 can be executed by the processor 820 to determine whether the steering wheel angle sensor 807 has failed or whether the pinion 804, rack 805, pinion sensor 809, or rack sensor 810 has failed. Additionally, instructions 824 stored in the memory 822 can be executed by the processor 820 to perform any of the methods described herein or implement any functionality described herein.

[0038] The modules and controllers described herein can include software, hardware, or computing devices that include a non-transitory computer-readable medium, such as, but not limited to, a memory storing instructions thereon, and a processor for executing the instructions to perform the actions, steps, methods, and functionality described herein. Multiple modules and controllers and their associated actions, steps, methods, and functionality can be included in or implemented by one or more computing devices.

[0039] The following description of variations is merely illustrative of components, elements, actions, products, and methods considered to be within the scope of the present invention and is not intended in any way to limit such scope by what is specifically disclosed or not explicitly set forth. The components, elements, actions, products, and methods described herein can be combined and rearranged differently than as specifically described herein and still be considered within the scope of the present invention.

[0040] Variation 1 can include a product including a non-transitory computer-readable medium having instructions thereon executable by an electronic processor to implement functionality, the functionality including: receiving a vehicle dynamics data input; receiving or calculating one or more stability indicators and thresholds; using the stability indicator duration and magnitude to determine whether an instability event is occurring; if an instability event is occurring, calculating a first braking and steering modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned braking and steering modification, or the previously stored stability memory data.

[0041] Variation 2 can include the product according to Variation 1, further including estimating a new maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input if an instability event is occurring.

[0042] Variation 3 can include the product according to Variation 2, further including calculating a first learned Mu estimate using the first estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

[0043] Variant 4 may include the product according to any one of Variants 1 - 3, further comprising monitoring the received vehicle dynamics data input to determine whether vehicle maneuvers exceed the currently estimated maximum achievable vehicle acceleration if an instability event does not occur.

[0044] Variant 5 may include the product according to Variant 4, further comprising calculating a second brake - steer modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the currently learned brake - steer modification, or the previously stored stability memory data if the vehicle acceleration exceeds the currently estimated maximum achievable vehicle acceleration without an instability event occurring.

[0045] Variant 6 may include the product according to Variant 5, further comprising estimating a second maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input.

[0046] Variant 7 may include the product according to Variant 6, further comprising calculating a second learned Mu estimate using the second estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

[0047] Variant 8 may include the product according to any one of Variants 1 - 8, further comprising using the first brake - steer modification to actively, reactively, and non - temporarily change at least one of the brake - steer braking or powertrain commands.

[0048] Variant 9 may include the product according to Variant 8, wherein changing at least one of the brake - steer braking or powertrain commands using the first brake - steer modification occurs before activation of the brake - steer function.

[0049] Variant 10 may include the product according to any one of Variants 1 - 9, further comprising using the first learned Mu estimate to enhance brake - steer functionality.

[0050] Variant 11 may include the product according to any one of Variants 1 - 10, further comprising transmitting the first learned Mu estimate to other vehicle functions.

[0051] Variant 12 may include a method of performing an action using an electronic controller, including: receiving a vehicle dynamics data input; receiving or calculating one or more stability indicators and thresholds; using the stability indicator duration and magnitude to determine whether an instability event is occurring; if an instability event is occurring, calculating a first braking and steering modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned braking and steering modification, or the previously stored stability memory data.

[0052] Variant 13 may include the method according to Variant 12, further including, if an instability event is occurring, estimating a new maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input.

[0053] Variant 14 may include the method according to Variant 13, further including calculating a first learned Mu estimate using the first estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

[0054] Variant 15 may include the method according to any one of Variants 12-14, further including, if an instability event has not occurred, monitoring the received vehicle dynamics data input to determine whether the vehicle maneuver exceeds the current estimated maximum achievable vehicle acceleration.

[0055] Variant 16 may include the method according to Variant 15, further including, if the vehicle acceleration exceeds the current estimated maximum achievable vehicle acceleration without an instability event occurring, calculating a second braking and steering modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned braking and steering modification, or the previously stored stability memory data.

[0056] Variant 17 may include the method according to Variant 16, further including estimating a second maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input.

[0057] Variant 18 may include the method according to Variant 17, further including calculating a second learned Mu estimate using the second estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

[0058] Variant 19 may include the method according to any one of Variants 12-18, further including using the first braking and steering modification to actively, reactively, and non-temporarily change at least one of the braking and steering brakes or the powertrain commands.

[0059] Variant 20 may include the method according to any one of variants 19, wherein changing at least one of the brake steer brakes or powertrain commands using the first brake steer modification occurs before activation of the brake steer function.

[0060] Variant 21 may include the method according to any one of variants 12 - 20, further comprising enhancing brake steer functionality using the first learned Mu estimate.

[0061] Variant 22 may include the method according to any one of variants 12 - 21, further comprising transmitting the first learned Mu estimate to other vehicle functions.

[0062] The foregoing description of alternative variants within the scope of the invention is illustrative in nature only, and thus, variations or modifications thereof should not be regarded as departing from the spirit and scope of the invention.

Claims

1. A product comprising a non - transitory computer - readable medium having instructions thereon that are executable by an electronic processor to implement functionality, the functionality including: Receiving a vehicle dynamics data input; Receiving or calculating one or more stability indicators and thresholds; Using the stability indicator duration and magnitude to determine whether an instability event is occurring; If an instability event is occurring, calculating a first brake - steer modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned brake - steer modification, or the previously stored stability memory data.

2. The product according to claim 1, further comprising estimating a new maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input if an instability event is occurring.

3. The product according to claim 2, further comprising calculating a first learned Mu estimate using the first estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

4. The product according to claim 1, further comprising monitoring the received vehicle dynamics data input to determine whether the vehicle maneuver exceeds the current estimated maximum achievable vehicle acceleration if an instability event does not occur.

5. The product according to claim 4, further comprising calculating a second brake - steer modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned brake - steer modification, or the previously stored stability memory data if the vehicle acceleration exceeds the current estimated maximum achievable vehicle acceleration without an instability event occurring.

6. The product according to claim 5, further comprising Estimating a second maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input.

7. The product according to claim 6, further comprising calculating a second learned Mu estimate using the second estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

8. The product according to claim 1, further comprising using the first brake - steer modification to actively, reactively, and non - transitorily change at least one of the brake - steer brake or powertrain commands.

9. The product according to claim 8, wherein, Using the first brake - steer modification to change at least one of the brake - steer brake or powertrain commands occurs before the brake - steer function is activated.

10. The product according to claim 1, further comprising using the first learned Mu estimate to enhance the brake - steer functionality.

11. The product according to claim 1, further comprising transmitting the first learned Mu estimate to other vehicle functions.

12. A method of performing actions using an electronic controller, comprising: Receiving a vehicle dynamics data input; Receiving or calculating one or more stability indicators and thresholds; Use the instability indicator duration and magnitude to determine if an instability event is occurring; If an instability event is occurring, calculate a first brake-steer modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned brake-steer modification, or the previously stored stability memory data.

13. The method of claim 12, further comprising, if an instability event is occurring, estimating a new maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input.

14. The method of claim 13, further comprising calculating a first learned Mu estimate using the first estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

15. The method of claim 12, further comprising, if an instability event is not occurring, monitoring the received vehicle dynamics data input to determine if vehicle maneuvers exceed the current estimated maximum achievable vehicle acceleration.

16. The method of claim 15, further comprising, if the vehicle acceleration exceeds the current estimated maximum achievable vehicle acceleration without an instability event occurring, calculating a second brake-steer modification using at least one of the current vehicle dynamics data input, the current Mu estimate, the current learned brake-steer modification, or the previously stored stability memory data.

17. The method of claim 16, further comprising estimating a second maximum achievable vehicle acceleration from the stored stability memory data based on the received vehicle dynamics data input.

18. The method of claim 17, further comprising calculating a second learned Mu estimate using the second estimated maximum achievable vehicle acceleration, the previously estimated maximum achievable vehicle acceleration, the current estimated Mu value, and the previously estimated Mu value.

19. The method of claim 12, further comprising using the first brake-steer modification to actively, reactively, and non-temporarily change at least one of the brake-steer braking or powertrain commands.

20. The method according to claim 19, wherein, Using the first brake-steer modification to change at least one of the brake-steer braking or powertrain commands occurs before the brake-steer function is activated.

21. The method of claim 12, further comprising using the first learned Mu estimate to enhance brake-steer functionality.

22. The method of claim 12, further comprising transmitting the first learned Mu estimate to other vehicle functions.

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