INTELLIGENT VEHICLES AND CONTROL LOGIC FOR ESTIMATING THE BRAKING TORQUE REQUIREMENT FOR COOPERATIVE CONTROL OF THE BRAKING SYSTEM

Abstract

A method of operating a motor vehicle, the motor vehicle comprising a plurality of road wheels, a friction braking system, a powertrain system, and an input device operable to receive control inputs from an operator of the motor vehicle, the method comprising: Receiving, via a vehicle controller by the operator via the input device, a vehicle control command with an associated torque request for the motor vehicle; Determining, via the vehicle controller, a drive actuator limitation that limits a braking torque available from a driveline actuator of the driveline system; Determining, via the vehicle controller, a drive braking torque distribution for the road wheels of the motor vehicle and a maximum braking torque capacity for the driveline actuator using the drive actuator limitation and the operator-inputted torque request; Determining a first friction brake torque request using the drive brake torque distribution, the torque request, and a vehicle control mode of the powertrain system; Determining a second friction braking torque request using the maximum braking torque capacity, the torque request, and the vehicle control mode; Determining a final friction braking torque command by arbitrating between the first and second friction braking torque requirements based on a braking torque optimization decision; and Transmitting, via the vehicle controller, the final friction braking torque command to the friction braking system and a final powertrain braking command to the powertrain actuator; further comprising: Determining a road load correction based on a speed profile of the motor vehicle; and Calculating, via the vehicle control, a compensated torque request as the sum of the torque request and the road load correction when the vehicle control mode of the powertrain system is a cruise control mode. wherein determining the first and second friction braking torque includes the requirement: Using the compensated torque request as the torque request in response to the vehicle control mode being in the speed control mode; and Using the torque request uncompensated by the road load correction in response to the vehicle control mode not being in cruise control mode, wherein determining the first friction braking torque request comprises calculating a mathematical difference between: (1) the compensated torque request or the uncompensated torque request and (2) a sum of individual actuator torque requests included in the drive braking torque distribution for the road wheels of the motor vehicle, wherein determining the second friction braking torque request comprises calculating a mathematical difference between: (1) the compensated torque request or the uncompensated torque request and (2) the maximum braking torque capacity of the powertrain actuator determined from the drive actuator constraint.

Description

INTRODUCTION

[0001] The present disclosure relates generally to powertrain and braking systems for motor vehicles. More particularly, aspects of this disclosure relate to cooperative friction braking and driveline braking for single-pedal driving of motor vehicles.

[0002] Today's production vehicles, such as the modern automobile, are originally equipped with a powertrain that propels the vehicle and supplies the vehicle's on-board electronics. In motor vehicles, for example, the powertrain typically consists of a prime mover that transmits drive torque to the vehicle's final drive (e.g., differential, axle shafts, wheels, etc.) via an automatic or manual transmission. Motor vehicles have always been powered by piston internal combustion engines because they are readily available, relatively inexpensive, lightweight, and highly efficient. These engines include compression-ignition (CI) diesel engines, spark-ignition (SI) gasoline engines, two-, four-, and six-stroke engines, and rotary engines, to name just a few.Hybrid electric and fully electric vehicles (collectively referred to as “electric vehicles”), on the other hand, use alternative energy sources to power the vehicle, thus minimizing or eliminating the dependence on a fossil fuel-based engine for traction power.

[0003] A fully electric vehicle (FEV)—also colloquially referred to as an "electric car"—is an electric-powered vehicle configuration that completely eliminates the internal combustion engine and associated peripheral powertrain components, utilizing a rechargeable energy storage system (RESS) and a traction motor for vehicle propulsion. The fuel supply and exhaust systems of an internal combustion engine vehicle are replaced in a battery-assisted FEV by one or more traction motors, a traction battery pack, and battery cooling and charging technology. Hybrid electric vehicle (HEV) powertrains, on the other hand, utilize multiple traction power sources to propel the vehicle, typically operating an internal combustion engine in conjunction with a battery- or fuel-cell-powered traction motor.Because electric vehicles are capable of deriving their power from sources other than the engine, HEV engines can be fully or partially shut down while the vehicle is powered by the electric motor(s).

[0004] In hybrid and fully electric vehicles, a vehicle motion controller (VMC) can be used to interpret the driver's accelerator pedal position and derive a desired axle torque. The VMC can then match the driver's desired axle torque with the torque requests of the advanced driver assistance system (ADAS) and the torque requests of the automated vehicle (e.g., speed mitigation, traction or stability control, adaptive cruise control (ACC), etc.). A final axle torque request is then sent from the VMC to a powertrain control module (PCM) or brake control module (BCM) to evaluate how to use a combination of actuators, such as the engine, traction motor(s), transmission, friction brakes, etc., to achieve a final desired axle torque.When the vehicle is moving forward and the driver releases the accelerator (a "rollover maneuver"), the VMC can automatically apply negative axle torque to decelerate the vehicle. In electric vehicles, a desired negative axle torque can be generated by a "cooperative braking system" through the combined application of negative engine torque and the vehicle's friction braking system.

[0005] DE 10 2014 102 896 A1 describes a method comprising determining a cruise control torque request based on a following distance of a vehicle and / or a rate at which the vehicle approaches an object.

[0006] DE 10 2008 017 478 A1 describes a method for operating a vehicle braking system for motor vehicles with hybrid drive or electric drive, in which hydraulically actuated wheel brakes are preferably provided on the front axle, wherein the vehicle wheels assigned to the rear axle are at least partially driven by an electric motor which can be operated as a generator to recover (recuperate) braking energy and, in generator mode, exerts a braking force (recuperation torque) on the vehicle wheels assigned to the respective axle.

[0007] DE 10 2015 102 925 A1 describes methods for operating a vehicle with a friction braking system and a regenerative braking system. The method determines a regenerative torque capacity, calculates a desired regenerative torque magnitude for the braking system, and detects that the desired regenerative torque magnitude exceeds the regenerative torque capacity by at least a threshold value.

[0008] US 2018 / 0 093 572 A1 describes a friction braking system and a regenerative braking system separate from a vehicle. According to certain embodiments, the regenerative braking system may include at least one actuator and a controller. The controller may be configured to: determine whether an accelerator pedal is depressed; if the accelerator pedal is depressed, determine an amount of regenerative braking based on the behavior of the accelerator pedal.

[0009] DE 11 2016 001 509 T5 describes a brake control device capable of suppressing a sense of discomfort felt by a driver. A brake control device includes a brake command addition section for adding an automatic braking brake command value output from an automatic braking brake command calculation section.

[0010] DE 10 2018 133 649 A1 relates to a method for operating a drive train of a motor vehicle. The drive train comprises a first control unit, by means of which at least one braking torque for braking the motor vehicle can be adjusted.

[0011] In addition, the drive train comprises a second control unit provided in addition to the first control unit, by means of which drive devices can be controlled in order to thereby adjust a respective torque to be provided by the respective drive device for driving a respective wheel of a respective axle.

[0012] DE 100 49 567 A1 describes a vehicle control device for controlling an all-wheel drive motor vehicle of a type having a first drive power source for driving one of a pair of front wheels and a pair of rear wheels and a second drive power source for driving the other of the pair of front wheels and the pair of rear wheels, the vehicle control device being designed.

[0013] US 2018 / 0 326 852 A1 describes a method in which a magnitude of a road surface slope along which a vehicle is traveling is detected. As the magnitude of the road surface slope increases, a preset basic braking force is corrected to decrease based on the magnitude of the road surface slope, or a preset basic driving force is corrected to increase based on the magnitude of the road surface slope.

[0014] DE 10 2018 105 292 A1 describes methods and systems for operating a powertrain of a hybrid vehicle including an internal combustion engine, an electric motor, and a transmission. In one example, a regenerative torque and a torque of an electronically controlled differential clutch are adjusted to enhance the utilization of a vehicle's kinetic energy. DESCRIPTION

[0015] The object of the invention is to make a method for operating a motor vehicle more user-friendly. This object is achieved by the subject matter according to claim 1. Further developments can be found in the subclaims.

[0016] The paper presents feedback control systems with associated control logic for optimized estimation of vehicle braking torque, methods for manufacturing and operating such systems, and intelligent electrically powered vehicles with cooperative friction brake and drive actuator braking systems for one-pedal driving (OPD). As examples, controller architectures and methods for calculating braking torque demand values ​​and, based on these calculated values, for coordinating one or more drive actuators with one or more friction brake actuators of a cooperative braking system of a vehicle to achieve a desired final braking torque demand value are presented.To derive the final braking torque request, the system can shape the driver's torque request using transient acceleration data to account for both real-time friction braking torque requirements and real-time driveline component requirements. The control system can also calculate friction brake torque requests to avoid backfilling during VMC torque bursts or, alternatively, to backfill during VMC torque bursts. Friction braking torque values ​​can be calculated by determining the driver's torque request while considering the road load when the VMC is in a cruise control mode.

[0017] The benefits of at least some of the presented concepts include an intelligent, OPD-capable vehicle with improved friction braking torque estimation for optimized cooperative braking system control. In the case of engine braking during regenerative braking (regen) in an HEV or FEV, predefined battery conditions, such as a high state of charge (SOC), may prevent the motor(s) alone from providing the required braking torque. The control methods presented here complement a powertrain brake actuator with a friction braking system brake actuator to provide the desired deceleration torque when the powertrain actuator(s) alone cannot meet the requirements.In addition to the aforementioned benefits, the described features can also help reduce system complexity and calibration time, improve powertrain response time, enhance vehicle drivability, and optimize tipping and untip operations.

[0018] Aspects of this disclosure relate to system control logic, feedback control methods, and computer readable media (CRM) for optimized vehicle braking torque estimation for cooperative braking systems. In one example, a method of operating a motor vehicle, including ICE, HEV, and FEV powertrain configurations, is presented. This representative method comprises, in any order and in any combination with the options and features disclosed above and below: receiving a vehicle control command with an associated torque request for maneuvering the motor vehicle via a resident or remote vehicle control unit from a driver, occupant, or vehicle subsystem (collectively, "operator") via an electronic input device (e.g., accelerator pedal, brake pedal, telematics unit, communications bus, etc.); determining a drive actuator constraint (e.g.,Battery power limitation, axle torque limitation, vehicle motion control (VMC) compensation limitation, etc.) that limits a braking torque capacity available from one or more powertrain actuators of the vehicle's powertrain system; and determining a drive braking torque distribution for the road wheels of the motor vehicle (e.g., distribution across axles 1, 2, ...n) and a maximum effective braking torque capacity available from the powertrain actuator(s). Continuing the discussion of the above example, the method also includes: in response to a negative braking torque request, determining a first friction braking torque request based at least in part on the drive braking torque distribution, the operator-input torque request, and a vehicle control mode of the powertrain system (e.g.,, speed control mode or torque control mode); in response to the negative braking torque demand, determining a second frictional braking torque demand that is at least partially based on the maximum braking torque capacity, the torque demand input by the operator, and the vehicle control mode; determining a final frictional braking torque command by arbitrating between the two frictional braking torque demands based on a braking torque optimization decision; and wherein the vehicle control transmits the final frictional braking torque command to the frictional braking system (e.g., from the VMC to an electronic brake control module (EBCM)) and a final driveline braking command to the driveline actuator (e.g., from the VMC to a special PIM sub-module for a traction motor or an electric drive unit).

[0019] Further aspects of this disclosure relate to closed-loop control systems and intelligent motor vehicles with optimized friction brake torque estimation for a cooperative braking system, e.g., for performing single-pedal driving. As used herein, the terms "vehicle" and "motor vehicle" may be used interchangeably and synonymously to include any relevant vehicle platform, such as passenger cars (ICE, HEV, FEV, fuel cell, fully and semi-autonomous vehicles, etc.), commercial vehicles, industrial vehicles, tracked vehicles, off-road and all-terrain vehicles (ATVs), motorcycles, agricultural equipment, watercraft, aircraft, etc. A motor vehicle includes, for example, a vehicle body with a passenger compartment, a plurality of wheels attached to the body, and other standard equipment. In electric-powered vehicles, one or more electric traction motors operate alone (e.g.,in FEV powertrains) or in conjunction with an internal combustion engine assembly (e.g., in HEV powertrains) to selectively drive one or more of the wheels to propel the vehicle. A friction braking system can selectively slow or stop the electrically powered vehicle. An electronic input device, which may be embodied as an accelerator pedal only, an accelerator and brake pedal, a joystick controller, or a similarly suitable input device, is used to receive vehicle control inputs from a vehicle operator.

[0020] Continuing with the discussion of the above example, the vehicle also includes an on-board or off-board vehicle control module programmed to receive one or more vehicle control commands with associated torque requests for the motor vehicle and to identify any drive actuator constraints that limit the braking torque capacity available from one or more driveline actuators of the powertrain system. Using the drive actuator constraint and the torque request, the vehicle controller determines a drive braking torque distribution for the vehicle wheels and a maximum braking torque capacity for the powertrain actuator(s). A first friction braking torque request is calculated using the drive braking torque distribution, the torque request, and a vehicle control mode of the powertrain system.Similarly, a second friction braking torque request is calculated using the maximum braking torque capacity, the torque demand, and the vehicle control mode. A final friction braking torque command is derived by deciding between the first and second friction braking torque requests based on a braking torque optimization decision. Based on this determination, the final friction braking torque command is transmitted to the friction braking system and a powertrain braking command is transmitted to the powertrain actuator(s).

[0021] For each of the disclosed systems, methods, and vehicles, a road load correction may be determined based on a road grade and / or a speed profile of the motor vehicle. When the vehicle control mode is set to cruise control mode, the vehicle controller may responsively calculate a compensated torque request as the sum of the torque request and the road load correction. In this case, the compensated torque request is used to determine the friction brake torque request values ​​when the vehicle control mode is set to cruise control mode. However, when the vehicle control mode is set to another control mode, an uncompensated torque request is used to determine the friction brake torque request values.Determining the first friction braking torque request may, for example, involve calculating the difference between: (1) the torque request or the compensated torque request, and (2) a sum of the individual torque requests included in the drive braking torque distribution for the road wheels of the motor vehicle. Furthermore, determining the second friction braking torque request may involve calculating the difference between: (1) the torque request or the compensated torque request, and (2) the maximum braking torque capacity of the powertrain actuator determined from the drive actuator constraint.

[0022] In all of the disclosed systems, methods, and vehicles, in response to the maximum braking torque capacity for the powertrain actuator being insufficient to meet the operator's torque request, the decision between friction braking torque request values ​​may involve blending the two friction braking torque requests, emphasizing or incorporating a larger percentage of the first friction braking torque request ("blending toward"). However, if estimated or sensed vehicle dynamics data indicates that the drive braking torque distribution is insufficient to meet the operator's torque request, the decision between friction braking torque requests may involve blending the friction braking torque requests with a larger percentage of the second friction braking torque request.As a further option, the vehicle controller may receive sensor signals from a speed sensor indicating a real-time vehicle speed of the motor vehicle and select the vehicle control mode as a speed control mode or a torque control mode using the real-time vehicle speed. The vehicle control mode may also be determined based on pedal position and / or road gradient data.

[0023] In all of the disclosed systems, methods, and vehicles, the controller may receive an OPD level selection input, a brake pedal position input, a brake boost on demand (ROD) input, and / or a park rear neutral drive low (PRNDL) input and, based on one or more of these signals, determine the torque request associated with the operator-input vehicle control command. The operator-input torque request may also be based on a previous final friction brake torque command already communicated to the friction brake system.As a further option, the vehicle control can use stored acceleration data to determine a negative torque command for the torque demand associated with the vehicle control command; this negative torque command is then shaped based on stored transient acceleration data.

[0024] For each of the disclosed systems, methods, and vehicles, the vehicle controller may adopt numerous alternative ECU and networked ECU architectures, including a vehicle motion controller and a Driver Command Interpreter (DCI) module contained within a Traction Power Inverter Control Module (TPIM). The VMC may communicate the powertrain brake command to one or more control modules that control the powertrain actuators. In this case, the friction brake system may include an electronic brake control module; the VMC communicates the friction brake torque command to the EBCM. In some vehicle applications, the motor vehicle has a battery pack, the powertrain actuator has an electric traction motor, and the drive actuator limitation includes a battery charge limit.Another possibility is that the input device is an accelerator pedal (the motor vehicle may not have a brake pedal) and the vehicle control command received from the operator is part of a braking operation resulting, for example, from a tipping maneuver in a one-pedal driving mode.

[0025] The above summary does not represent every embodiment or aspect of this disclosure. Rather, the above features and advantages, as well as other features and related advantages of this disclosure, will be readily apparent from the following detailed description of illustrative examples and modes for carrying out the present disclosure, when considered in conjunction with the accompanying drawings and the appended claims. Furthermore, this disclosure expressly includes all combinations and subcombinations of the elements and features presented above and below. BRIEF DESCRIPTION OF THE CHARACTERS Fig. 1 is a schematic diagram of a representative electric drive vehicle with a network of on-board control units, sensor devices, and communication devices for estimating friction braking torque for cooperative operation of the braking system during single-pedal driving in accordance with aspects of the presented concepts. Fig. 2 is a schematic diagram showing a representative controller architecture for providing optimized friction braking torque estimation for operating a cooperative braking system in accordance with aspects of the disclosed concepts. Fig. 3 is a flowchart illustrating a representative brake torque estimation control protocol for operating a cooperative braking system of a motor vehicle, which may correspond to memory-stored instructions executed by a stationary or remote controller, control logic circuit, programmable controller, or other integrated circuit (IC) or network of devices in accordance with aspects of the disclosed concepts.

[0026] Representative embodiments of this disclosure are illustrated by way of non-limiting examples in the drawings and are described in more detail below. It should be understood, however, that the novel aspects of this disclosure are not limited to the particular forms illustrated in the drawings enumerated above. Rather, the disclosure is intended to cover all modifications, equivalents, combinations, subcombinations, permutations, groupings, and alternatives falling within the scope of this disclosure, such as encompassed by the appended claims. DETAILED DESCRIPTION

[0027] This disclosure may be embodied in many different forms. Representative examples of the disclosure are illustrated in the drawings and are described in detail herein, these embodiments being presented as examples of the disclosed principles and not as limitations on the general aspects of the disclosure. To this end, elements and limitations described in, for example, the "Summary," "Introduction," "Description," "Description of the Drawings," and "Detailed Description" sections, but not expressly set forth in the claims, should not be incorporated into the claims, individually or in the aggregate, by implication, inference, or otherwise. Furthermore, the drawings discussed herein may not be to scale and are for instructional purposes only.Therefore, the specific and relative dimensions shown in the illustrations are not to be considered limiting.

[0028] For the purposes of this detailed description, unless expressly excluded: the singular includes the plural and vice versa; the words "and" and "or" apply in both the subjunctive and disjunctive moods; the words "each" and "all" mean "each and all"; and the words "including," "including," "comprising," "having," and permutations thereof each mean "including without limitation." In addition, words of approximation such as "approximately," "almost," "substantially," "generally," "about," and the like may be used herein to mean "at, near, or nearly at," or "within 0-5% of," or "within acceptable manufacturing tolerances," or any logical combination thereof.Finally, directional adjectives and adverbs such as "front", "rear", "inside", "outside", "starboard", "port", "vertical", "horizontal", "up", "down", "forward", "backward", "left", "right", etc., may refer to a motor vehicle, e.g., the forward travel of a motor vehicle when the vehicle is operated on a horizontal driving surface.

[0029] With reference to the drawings, in which like reference numerals refer to like features in the several views, Fig. 1 illustrates a representative automobile, generally designated 10, which is depicted here for discussion purposes as an electric-powered sedan. The depicted motor vehicle 10—also referred to herein as a "motor vehicle" or "vehicle" for short—is merely an exemplary application with which novel aspects of this disclosure may be practiced. Likewise, the incorporation of the present concepts into an all-electric vehicle powertrain should be understood as a non-limiting implementation of the disclosed features. It should be understood that aspects and features of this disclosure may be applied to other powertrain architectures, implemented for any logically relevant vehicle type, and used for both OPD and non-OPD applications. Furthermore, only selected components of the motor vehicles and vehicle control systems are shown and described in detail herein.Nonetheless, the vehicles and vehicle systems described below may include numerous additional and alternative features and other available peripheral components to perform the various methods and functions of this disclosure.

[0030] The representative vehicle 10 of Fig. 1 is originally equipped with a vehicle telecommunications and information unit (“telematics”) 14 that communicates wirelessly (e.g., via cell towers, base stations, mobile switching centers, satellite services, etc.) with a remote or “off-board” cloud computing host service 24. Some of the other vehicle hardware components 16 that are included in Fig. 1 include, by way of non-limiting examples, an electronic video display device 18, a microphone 28, one or more audio speakers 30, and various input controls 32 (e.g., buttons, knobs, pedals, switches, touchpads, joysticks, touchscreens, etc.). These hardware components 16 function, in part, as a human-machine interface (HMI) that allows the user to communicate with the telematics unit 14 and other systems and system components within the vehicle 10. The microphone 28 provides a vehicle occupant with the ability to input verbal or other audible commands; the vehicle 10 may be equipped with an embedded speech processing unit that utilizes software modules for audio filtering, processing, and analysis.Conversely, speaker 30 provides an audible output to a vehicle occupant and may be either a standalone speaker intended for use with telematics unit 14 or may be part of an audio system 22. Audio system 22 is operatively connected to a network connection interface 34 and an audio bus 20 to receive analog information and reproduce it as sound through one or more speaker components.

[0031] Communicatively coupled to the telematics unit 14 is a network connection interface 34, suitable examples of which include a twisted pair / fiber optic Ethernet switch, an internal / external parallel / serial communication bus, a local area network (LAN) interface, a controller area network (CAN), a media-oriented system transfer (MOST), a local interconnect network (LIN) interface, and the like. Other suitable communication interfaces may be those that conform to ISO, SAE, and IEEE standards and specifications. The network connection interface 34 enables the vehicle hardware 16 to send and receive signals to each other and to various systems and subsystems both within the vehicle body 12 and external to the vehicle body 12. In this way, the vehicle 10 can perform various vehicle functions, such as:The telematics unit 14, for example, receives and transmits signals and data to / from a powertrain control module (PCM) 52, an advanced driver assistance system (ADAS) module 54, a battery pack control (BPCM) module 56, a traction power inverter (TPIM) module 58, a brake system control (BSCM) module 60, and various other vehicle control modules such as a transmission control module (TCM), an engine control module (ECM), a sensor system interface module (SSIM), a climate control module (CCM), etc.

[0032] With further reference to Fig. 1, the telematics unit 14 is an in-vehicle computing device that provides a mix of services both individually and through its communication with other networked devices. This telematics unit 14 generally consists of one or more processors 40, each of which may be embodied as a discrete microprocessor, an application-specific integrated circuit (ASIC), or a dedicated control module. The vehicle 10 may provide centralized vehicle control via a central processing unit (CPU) 36 operatively coupled to one or more electronic storage devices 38, each of which may take the form of a CD-ROM, a magnetic disk, an integrated circuit (IC), flash memory, semiconductor memory (e.g., various types of RAM or ROM), etc., and a real-time clock (RTC) 42.

[0033] Long-range vehicle communication capabilities to remote, networked devices outside the vehicle may be provided via one or more or all of a cellular chipset / component, a navigation and positioning chipset / component (e.g., GPS transceiver), or a wireless modem, all shown collectively at 44. Short-range wireless connectivity may be provided via a short-range wireless communication device 46 (e.g., a BLUETOOTH® unit or an NFC transceiver), a Dedicated Short-Range Communications (DSRC) component 48, and / or a dual antenna 50. It should be understood that the vehicle 10 may be implemented without one or more of the components listed above or may optionally include additional components and functionality as desired for a particular end application.The various communication devices described above may be configured to exchange data as part of a periodic transmission in a vehicle-to-vehicle (V2V) communication system or a vehicle-to-everything (V2X) communication system, e.g., vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P), vehicle-to-device (V2D), etc.

[0034] The CPU 36 receives sensor data from one or more sensing devices using, for example, photodetection, radar, laser, ultrasound, optics, infrared, or other suitable technology for performing automated driving operation, including short-range communication technologies such as DSRC or Ultra-Wide Band (UWB). According to the example shown, the vehicle 10 may be equipped with one or more digital cameras 62, one or more range sensors 64, one or more vehicle speed sensors 66, one or more vehicle dynamics sensors 68, and the necessary filtering, classification, fusion, and analysis hardware and software for processing the raw sensor data. The type, placement, number, and interoperability of the distributed array of vehicle sensors can be individually or collectively adapted to a particular vehicle platform to achieve a desired level of autonomous vehicle operation.

[0035] To drive the electrically powered vehicle 10, an electrified powertrain is capable of generating and transmitting drive torque to one or more of the vehicle's wheels 26. The powertrain is Fig. 1 is generally represented by a rechargeable energy storage system (RESS), which may be in the form of a chassis-mounted traction battery pack 70 connected to an electric traction motor 78. The traction battery pack 70 generally consists of one or more battery modules 72, each comprising a stack of battery cells 74, such as lithium-ion, lithium polymer, or nickel-metal hydride battery cells of the pouch, can, or prismatic type. One or more electrical machines, such as traction motor / generator units (M) 78, draw electrical energy from, and optionally supply electrical energy to, the RESS battery pack 70. A dedicated power inverter module (PIM) 80 electrically connects the battery pack 70 to the motor / generator unit(s) 78 and modulates the transfer of electrical power between these units.

[0036] The battery pack 70 is configured so that module management, cell sensing, and module-to-module or module-to-host communication functions are integrated directly into each battery module 72 and are performed wirelessly via a corresponding wireless cell monitoring unit (CMU) 76. The CMU 76 may be a microcontroller-based, printed circuit board (PCB)-mounted sensor array with a GPS transceiver and RF capability, housed on or within the battery module enclosure. The battery module cells 74, the CMU 76, the enclosure, the coolant lines, the bus bars, etc., together comprise the cell module assembly. The described configuration eliminates the need for separate, hard-wired electronic modules and serial ports, as used in a cell sensor board-based topology.

[0037] During operation of the motor vehicle 10, inputs from the driver and the control module may result in different speed commands with corresponding responses for torque and acceleration or deceleration. Regardless of whether the vehicle is an ICE, FEV, or HEV powertrain, and regardless of whether the vehicle is equipped with a single accelerator pedal or both a brake and accelerator pedal, it may be desirable for the vehicle 10 to be capable of executing a speed command as part of a one-pedal drive (OPD) operation. As the name suggests, OPD operation allows the driver to start, accelerate, cruise, pitch in, pitch out, decelerate, and / or stop the vehicle using a single pedal (accelerator pedal).During OPD operation, a driver-input speed command can be interpreted with an accompanying deceleration request, which is then correlated with a desired braking torque demand value. This deceleration request can then be combined with a desired acceleration request to calculate a final speed profile that meets the OPD drivability criteria. The actual friction braking torques applied to each wheel can be fed back to the VMC, allowing a cruise control system to regulate the activation of the friction brakes in addition to one or more driveline actuators to achieve the desired speed. The drive and friction brake torques can then be optimized to minimize the difference between the predicted future vehicle speeds and the desired speed profile.

[0038] The following introduces protocols for controlling cooperative braking systems that optimize the friction braking torque calculation to coordinate the powertrain actuators with the friction brake actuators in a cooperative braking operation. The presented methods can use an optimization state of the VMC to determine whether the braking torque calculations are limited by system constraints or by vehicle dynamic requirements. The control architecture implements feedback and feedforward inputs to synchronize one or more powertrain actuators (e.g., engine friction, engine brake, transmission brake, etc.) with one or more friction brake actuators (e.g., disc brake, drum brake, etc.) and optionally with one or more other vehicle actuators (e.g., active aircraft devices) to achieve a desired final braking torque.

[0039] To coordinate actuator control, VMC and torque capacity calculations may be limited by innate limitations in the capabilities of the drivetrain's drive actuators. A separate friction brake generator can be used to compare a limited VMC / torque capacity with a driver torque request to calculate a final friction brake torque request. The described methods can also shape a driver's torque request to account for both drive and friction brake torque requirements: A past torque request can be used to shape a current torque request, incorporating both a drive brake torque request value and a friction brake torque request value.In a tip-in scenario, shaping can first remove a friction brake torque request before applying drive torque to allow a smooth transition out of friction brake and into drive torque consistent with acceleration map-based torque shaping.

[0040] The friction brake torque request may be calculated to avoid backfilling a VMC torque portion, e.g., to account for vehicle dynamics constraints. For example, a friction brake torque request may be calculated prior to the VMC calculations based on a driver torque request and a system regeneration capacity constrained by drive actuator capacity limits (e.g., battery power limits, motor / axle torque limits, etc.). A calculated friction brake torque request may be communicated to the VMC to modify the driver torque request such that the VMC is responsible for achieving a remaining portion of the driver torque request using the drive actuator(s). Alternatively, a friction brake torque request may be calculated to compensate for a VMC torque reduction, e.g.,to account for system limitations. For example, the friction brake torque request can be calculated based on one or more VMC torque requests, constrained by the actuator capacity limits and the driver torque request. Another option is to calculate a friction brake torque when the VMC is regulating speed; the torque requested by the driver via the pedal can be supplemented by road loading compensation using a speed profile merging factor to obtain an effective torque. A friction brake command can then be calculated based on the driver's effective torque request. Optionally, a friction brake request can be calculated as a function of a brake torque capacity and an actual / commanded / estimated friction brake torque, e.g.using other actuators to meet the deceleration demand in cases where the capacity of the friction braking system is saturated (e.g. active aerodynamics, transmission, engine braking).

[0041] Fig. Figure 2 schematically shows a representative control architecture 100 for providing an optimized estimate of the friction braking torque to improve the operation of a cooperative braking system of a motor vehicle, such as the motor vehicle 10 of Fig. 1. In the example shown, a traction power inverter module 102 exchanges data with an electronic brake control module 104 to perform a cooperative braking operation. For example, the TPIM 102 may receive an accelerator torque request T accped from an accelerator pedal position (APP) sensor of an electronic accelerator pedal via a vehicle powertrain module (VPM) 106. Likewise, the EBCM 104 may receive a brake pedal torque request T decpedfrom a brake pedal position (BPP) sensor of an electronic brake pedal via a brake control module (BCM) 108. The brake pedal position and / or torque request data may also be communicated directly from the BCM 108 to the TPIM 102. Other vehicle control inputs received via the TPIM 102 may include an OPD level selection (e.g., input by a driver via the telematics unit (TU) 14 or other suitable input device), an ROD signal S (e.g., ROD . B. output from the TU 14 or from an ROD hardware unit) and / or a PRNDL signal S (Park-Rear-Neutral-Drive-Low) PRNDL from a switching mechanism 110 (e.g., input controls 32).

[0042] From these various vehicle control inputs, the TPIM 102 may output a brake boost signal, an achieved brake boost signal, and a drive friction brake request signal Tfricbr. One or more of these output signals may be received, filtered, and processed by the EBCM 104. The EBCM 104, on the other hand, may output a brake regeneration request signal, an achieved drive friction brake signal, and a drive friction brake capacity signal Tfricbrcap. One or more of the EBCM signal outputs may be received, filtered, and processed by the TPIM 102. In addition to cooperatively controlling the operation of the friction brake system's braking device(s) and the traction motor(s), the TPIM 102 may output one or more control command signals to one or more other driveline actuators, such asthe internal combustion engine assembly or the multi-speed power transmission, or to other vehicle actuators, such as an active aerodynamic device (“active aero”), to actively assist in reducing vehicle speed.

[0043] The TPIM 102 unit contains a DCI 112 (Driver Command Interpreter) control unit, which summarizes, filters, and processes the vehicle control input signals listed above received by the TPIM 102. From these signals, the DCI 112 outputs a desired torque request T des and a desired speed requirement V desto a Vehicle Motion Controller (VMC) 114, also included in the TPIM 102 unit. In addition to the desired torque and speed requirements, the VMC 114 aggregates, filters, and processes constraints for the brake system actuators, including, as non-limiting examples: axle torque minimum / maximum limit signals ST Amin / max for the front and rear axles of the vehicle; wheel torque minimum / maximum limit signals ST Wmin / max for the individual wheels 26 of the vehicle; total torque minimum / maximum limit signals S Ttot ; and T FtotTotal friction brake torque S feedback signals. To control actuator-assisted powertrain braking, e.g., regenerative braking torque, the VMC 114 outputs powertrain braking torque command signals Tpwrtbr for the vehicle's wheels 26. To control the actuator-assisted friction braking system, the VMC 114 outputs friction brake torque command signals Tfricbr to the EBCM 104. The EBCM 104, in turn, outputs friction brake pressure signals P FB for the individual wheel units.

[0044] Referring to the flowchart of Fig. 3, at 200, an improved method or control strategy for performing friction brake torque estimation for the operation of a cooperative braking system of a motor vehicle, such as the vehicle 10 of Fig. 1, during the execution of a desired vehicle maneuver, such as a one-pedal driving operation, in accordance with aspects of the present disclosure. Some or all of the Fig. 3 and described in more detail below may represent an algorithm corresponding to processor-executable instructions stored, for example, in a main or auxiliary or remote memory (e.g., storage device 38 of Fig. 1) and are stored and executed, for example, by an electronic control unit, a processing unit, a logic circuit or another module or device or a network of modules / devices (e.g. CPU 36 of Fig. 1) to perform any or all of the functions described above and below associated with the disclosed concepts. It should be recognized that the order of execution of the illustrated operation blocks may be changed, additional operation blocks may be added, and some of the described operations may be modified, combined, or eliminated.

[0045] The procedure 200 of Fig. 3 begins at terminal block 201 with processor-executable instructions stored in memory for a programmable controller or control module, or a similarly suitable processor, to invoke an initialization procedure for a vehicle braking system control protocol. This routine may be executed in real time, continuously, systematically, sporadically, and / or at regular intervals, e.g., every 10 or 100 milliseconds during normal and ongoing operation of the motor vehicle 10. As a further option, terminal block 201 may be initiated in response to a user command prompt, a vehicle control module prompt, or a command received from an "external" centralized host system (e.g., the cloud computing service 24 of Fig. 1) received broadcast input signal. After completion of the Fig. 3, the method 200 may proceed to terminal block 223 and temporarily terminate, or optionally return to terminal block 201 and run in a continuous loop.

[0046] At process block 203, method 200 receives a driver-requested speed increase or decrease via an on-board input device. As one non-limiting example, a driver releases (or presses) an accelerator pedal to input a deceleration (or acceleration) command to the motor vehicle. This vehicle control command may be accompanied by a speed change control command provided by a resident vehicle control device, such as the ADAS module 54 of Fig. 1, is output. As discussed above in the discussion of Fig. 2, the control system can also receive ROD and PRNDL operator selections that affect the final determination of the driver's torque request. For example, a PRNDL signal S PRNDL indicate that the vehicle's powertrain has been shifted into a low gear (L1 or L2); this may result in the selection of a different vehicle-calibrated pedal map or acceleration map to interpret the driver's pedal input. Similarly, an ROD signal S RODindicate that the driver wishes to increase the RESS charge through regenerative braking while simultaneously overriding a desired deceleration, e.g., by requesting a greater deceleration. As a further option, the driver can also change a desired acceleration map by selecting a different OPD level on the instrument panel. The initial torque request analysis may also consider an existing (previously commanded) final friction braking torque request, which is issued by the VMC 114 to the EBCM 104 and returned as a feedback control signal to the DCI 112.

[0047] Upon receipt of the driver-input vehicle control command(s), commands to be executed by the controller may cause the VMC 114 to determine, for example, based on vehicle-calibrated acceleration data, a torque request corresponding to the driver-input speed change command and any accompanying speed change commands generated by the controller. This acceleration table may include a memory-accessible acceleration map file that maps a sequence of vehicle speeds and vehicle acceleration / deceleration values ​​with a corresponding sequence of positive / negative torque outputs.Raw pedal travel data indicating a desired acceleration / deceleration can be used to map a driver torque request as a function of measured vehicle speed and accelerator pedal position received from a pedal sensor. As a further option, the mapping described above can also be achieved by accessing a map file correlating vehicle pedal position with vehicle acceleration / deceleration.

[0048] This "unshaped" operator torque request may be passed through a subroutine process block where it is "shaped" using a vehicle-calibrated acceleration table. The transient acceleration table may include a memory-stored, ECU-accessible transient acceleration map file. The transient map file may be a lookup table that defines vehicle braking torques in transition regions between adjacent vehicle braking torque output values ​​in the acceleration map file. As a non-limiting example, the transient map file may define a corresponding ramp rate (e.g., change in acceleration or torque per loop) between each pair of adjacent points in the acceleration map file as a function of vehicle speed and torque change, i.e.the difference between a desired torque and an actual torque. The driver's torque demand can be shaped by incorporating these acceleration / torque ramp rate responses to impart curvature to the torque demand profile.

[0049] The method 200 continues with process block 205 (in Fig. 3 shown twice) to identify a set of drive actuator constraints that may prevent the available drive actuators from achieving a desired braking torque. These constraints may include, individually or in any combination, battery charge limits; motor torque limits; motor friction torque limits; axle torque capacities for each vehicle axle (e.g., based on motor and half-shaft torque capacities); wheel unit capacities for each road wheel; and calibratable torque buffers for VMC feedback compensation. For driveline architectures with axles having independent left and right drive units, the smaller of the two torque capacities may be used for both drive units. These brake actuator constraints are subsequently used to determine a minimum effective output torque, as specified in process block 207.The minimum effective output torque capacity is the maximum braking torque capacity achievable by the powertrain actuator(s) under the given constraints. By way of example and without limitation, the minimum effective output torque capacity may be indicative of the total regenerative braking torque that can be produced by the entire powertrain system at the time of a desired vehicle braking event.

[0050] In addition to evaluating existing torque capacity constraints, method 200 also uses the drive actuator constraint(s) to derive an optimal torque distribution in process block 209. This optimal torque distribution may include a decision indicator for torque optimization and an optimized drive torque distribution. For example, the function may determine an optimal drive axle torque distribution (e.g., for vehicle axles 1, 2, ... N) that best meets the operator's requirements for the vehicle's longitudinal and lateral motion (i.e., vehicle motion for acceleration, deceleration, yaw, etc., to be initiated by the drive system). With respect to the control methodology of Fig. 3, there may be cases where this function is unable to meet the driver's request for longitudinal deceleration of the drive. Two representative cases are: (1) a drive component of the drivetrain is limited in its capabilities (e.g., lack of engine regeneration torque or battery charge capacity); and (2) the specification of a specific deceleration torque by the drivetrain system may result in lateral instability. In addition to allocating the drive torque commanded to the drive actuators, the optimal torque distribution control of block 209 may provide a torque optimization decision indicating that Case 1 or Case 2 is occurring at a specific reference time (e.g., during an OPD braking maneuver). The cooperative braking system control, i.e.The controller, i.e., the actuators of the friction braking system, can use this information to decide which calculated friction braking torque to use in process block 221, which is explained in more detail below. The derivation of the optimal torque distribution can be performed before the VMC and TPIM, as shown, or within the VMC and TPIM for other foreseeable controller architectures.

[0051] With further reference to Fig.3, the method 200 executes instructions stored at process block 211 to be executed by the controller to determine any road load compensation for a current vehicle speed profile. For example, a road load correction may be calculated based on an estimated or measured road grade, a nominal or estimated vehicle mass, and an estimate of the vehicle's rolling friction, linear drag, aerodynamic drag, etc., to "compensate" the torque request associated with the driver's desired speed increase / decrease.Applying the principles of Newtonian mechanics, a deceleration profile with a force variable F can be calculated as the mathematical sum of the driver-desired shaped torque, the applied braking torque, the road gradient force, and the road loading force (ro + r1*v + r2*v^2, where v is the measured vehicle speed). Furthermore, a mass variable m is either a preset nominal vehicle mass or an estimated / measured (real-time) vehicle mass. Under certain operating conditions, the actual road gradient is not taken into account; the road gradient force is therefore set to zero.

[0052] In process block 213, method 200 identifies a current vehicle control mode for the vehicle propulsion system. To complete the determination in process block 213, a vehicle speed sensor may output one or more sensor signals indicative of a real-time speed of the subject vehicle. This real-time vehicle speed data is used, either independently or in combination with a driver-generated input, to select a vehicle control mode. According to an illustrative example, the control mode may be set to either a speed control mode or a torque control mode. In cruise control mode, the transient acceleration map files may be interpreted as an acceleration request; brake pedal application may be interpreted as a deceleration request and accounted for in the speed profile.In torque control mode, the acceleration map and the torque request based on the transient acceleration map are provided by the VMC 114. Mode selection may be based on the real-time speed of the vehicle, a driver input device position (e.g., accelerator / brake pedal position), a rate of change of the driver input device position, and / or a measured road grade.

[0053] Once the road load compensation is determined in block 211 and the vehicle control mode is determined in block 213, the method 200 executes process block 215 to select either a compensated or uncompensated torque request for a subsequent set of friction brake torque request calculations. Process block 215 may first determine whether the vehicle control mode is in cruise control mode (or any of a number of predefined "compensating" vehicle control modes). For example, if the vehicle is not in cruise control mode, the road load correction will not be applied to the driver torque request. On the other hand, if the vehicle control mode is set to cruise control mode, a compensated torque request may be calculated via the VMC.A compensated torque demand can be calculated as the mathematical sum of the torque demand and the road load correction.

[0054] Using the compensated / uncompensated torque request, the drive torque distribution, and the minimum effective output torque capacity as inputs, process blocks 217 and 219 calculate the initial friction braking torque request for the vehicle's friction braking system. For example, in process block 217, an initial friction braking torque request may be calculated as the mathematical difference between: (1) the compensated / uncompensated torque request (depending on the current vehicle control mode) and (2) the mathematical sum of the individual torque requests (drive axle torques) included in the drive braking torque distribution for the vehicle axles / road wheels.Similarly, a second friction brake torque request may be calculated in process block 219 as the mathematical difference between: (1) the compensated / uncompensated torque request (depending on the current vehicle control mode) and (2) the maximum brake torque capacity available from the powertrain actuator(s). Alternatively, the friction brake torque request may be a calibration function of a driver torque request and a minimum effective output torque capacity. These calculations enable the feedback control system to coordinate the friction brake actuators with the drive brake actuators, taking into account the limitations of the drive actuators and the dynamic distribution of the drive actuators' brake torque.

[0055] After completing the friction braking torque calculations in process blocks 217 and 219, the method 200 executes process block 221 to determine a final desired friction braking torque request by mediating between the initial estimates of the friction braking torque request based on a braking torque optimization decision derived from the operator torque request and any drive actuator constraints. At least in some applications, the VMC 114 within the TPIM 102 considers a torque optimization decision included in the determination of the optimal torque distribution performed in process block 209. A torque optimization decision may indicate that the maximum braking torque capacity available from the powertrain actuator(s) is insufficient to meet the driver torque request (e.g.,the drive torque distribution may not satisfy the driver's longitudinal deceleration request). Method 200 may adjust the friction brake torque requests toward the first friction brake torque request. In particular, the cooperative brake control system may directly select or more strongly emphasize (i.e., use a larger percentage of) the friction brake torque request based on the commanded drive brake torque distribution.

[0056] Conversely, a torque optimization decision may mean that available (e.g., measured or estimated) vehicle dynamics data indicates that the drive torque distribution is insufficient to meet the operator's torque request (e.g., the drive torque distribution is causing lateral stability issues). In this case, method 200 may respond by blending the friction brake torque requests toward the second friction brake torque request. In other words, the cooperative brake control system may directly select or more heavily emphasize (i.e., use a larger percentage) the friction brake torque request based on the minimum effective output torque capacity.In practical application, when a friction demand is transitioned from the calculation before the VMC 114 to the calculation after the VMC 114, or vice versa, the control system is designed to avoid any discontinuity in the friction braking demand. A ramp function and / or a filter can be used to ensure that the demand is continuous and smooth. Since there is the possibility of transitioning from one friction braking torque to another, a rate limit can be applied within the ramp function to ensure a smooth transition. In other words, when propulsion system constraints limit vehicle deceleration, the final friction braking demand calculations are performed downstream of the VMC 114 to make optimal use of the propulsion system's capacity.However, if a driver torque request cannot be met due to vehicle stability constraints, final friction braking request calculations are performed upstream of the VMC to ensure that the VMC 114 can control any potential torque vectoring. At this time, one or more braking torque command signals are transmitted to the friction braking system and / or powertrain actuator(s) to collectively output a total braking torque sufficient to achieve the desired braking torque to satisfy the driver input command.

[0057] Aspects of this disclosure may, in some embodiments, be implemented by a computer-executable program of instructions, such as program modules, generally referred to as software applications or application programs, executed by any control device or the control variants described herein. Software may include, by way of non-limiting example, routines, programs, objects, components, and data structures that perform particular tasks or implement particular data types. The software may provide an interface that enables the computer to respond according to an input source. The software may also cooperate with other code segments to initiate a variety of tasks in response to received data associated with the source of the received data. The software may be embodied on a variety of storage media, such as CD-ROM, magnetic disk, and semiconductor memory (e.g.,different types of RAM or ROM).

[0058] Furthermore, aspects of the present disclosure may be practiced with a variety of computer system and computer network configurations, including multiprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, and the like. Furthermore, aspects of the present disclosure may be applied in distributed computing environments in which tasks are performed by stationary and remote processing devices connected via a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media, including memory devices. Aspects of the present disclosure may therefore be implemented in conjunction with various hardware, software, or a combination thereof in a computer system or other processing system.Each of the methods described herein may include machine-readable instructions for execution by (a) a processor, (b) a controller, and / or (c) any other suitable processing device. Any algorithm, software, control logic, protocol, or method disclosed herein may be embodied as software stored on a tangible medium, such as flash memory, solid-state memory, hard disk, CD-ROM, Digital Versatile Disk (DVD), or other storage device. The entire algorithm, control logic, protocol, or method, and / or portions thereof, may alternatively be executed by a device other than a controller and / or embodied in firmware or dedicated hardware in an available manner (e.g.,implemented by an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field-programmable logic device (FPLD), discrete logic, etc.). Although specific algorithms are described with reference to the flowcharts presented herein, many other methods for implementing the example machine-readable instructions may alternatively be used.

[0059] Aspects of the present disclosure have been described in detail with reference to the illustrated embodiments; however, those skilled in the art will recognize that many modifications may be made thereto without departing from the scope of the present disclosure. The present disclosure is not limited to the precise construction and compositions disclosed herein; all modifications, changes, and variations apparent from the foregoing descriptions are within the scope of the disclosure as defined by the appended claims. Furthermore, the present concepts expressly include all combinations and subcombinations of the foregoing elements and features.

Claims

[1] A method of operating a motor vehicle, the motor vehicle comprising a plurality of road wheels, a friction braking system, a powertrain system, and an input device operable to receive control inputs from an operator of the motor vehicle, the method comprising: Receiving, via a vehicle controller by the operator via the input device, a vehicle control command with an associated torque request for the motor vehicle; Determining, via the vehicle controller, a drive actuator limitation that limits a braking torque available from a driveline actuator of the driveline system; Determining, via the vehicle controller, a drive braking torque distribution for the road wheels of the motor vehicle and a maximum braking torque capacity for the driveline actuator using the drive actuator limitation and the operator-inputted torque request; Determining a first friction brake torque request using the drive brake torque distribution, the torque request, and a vehicle control mode of the powertrain system; Determining a second friction braking torque request using the maximum braking torque capacity, the torque request, and the vehicle control mode; Determining a final friction braking torque command by arbitrating between the first and second friction braking torque requirements based on a braking torque optimization decision; and Transmitting, via the vehicle controller, the final friction braking torque command to the friction braking system and a final powertrain braking command to the powertrain actuator; further comprising: Determining a road load correction based on a speed profile of the motor vehicle; and Calculating, via the vehicle control, a compensated torque request as the sum of the torque request and the road load correction when the vehicle control mode of the powertrain system is a cruise control mode. wherein determining the first and second friction braking torque includes the requirement: Using the compensated torque request as the torque request in response to the vehicle control mode being in the speed control mode; and Using the torque request uncompensated by the road load correction in response to the vehicle control mode not being in cruise control mode, wherein determining the first friction braking torque request comprises calculating a mathematical difference between: (1) the compensated torque request or the uncompensated torque request and (2) a sum of individual actuator torque requests included in the drive braking torque distribution for the road wheels of the motor vehicle, wherein determining the second friction braking torque request comprises calculating a mathematical difference between: (1) the compensated torque request or the uncompensated torque request and (2) the maximum braking torque capacity of the powertrain actuator determined from the drive actuator constraint. [2] The method of claim 1, wherein deciding between the first and second friction braking torque requirements includes: Blending the first and second friction braking torque requests with a larger percentage of the first friction braking torque request in response to the braking torque optimization decision indicating that the maximum braking torque capacity for the powertrain actuator is insufficient to achieve the torque request; and Blending the first and second friction brake torque requests with a larger percentage of the second friction brake torque request in response to the brake torque optimization decision indicating that sensed or estimated vehicle dynamics data indicates that the drive brake torque distribution is insufficient to achieve the torque request. [3] The method of claim 1, further comprising: Receiving a sensor signal indicative of a real-time vehicle speed of the motor vehicle via the vehicle controller from a speed sensor; and Selecting the vehicle control mode as cruise control mode or torque control mode using the real-time vehicle speed. [4] The method of claim 1, further comprising: Receiving an input signal for regenerative braking (regen) on demand, ROD, and / or an input signal for park-rear-neutral-drive-low, PRNDL; and Determining the torque request associated with the operator-input vehicle control command based on the ROD input signal and / or the PRNDL input signal. [5] The method of claim 1, wherein determining the torque request is further based on a final friction braking torque command previously communicated to the friction braking system. [6] The method of claim 1, further comprising: Determining a negative torque command for the torque request associated with the operator-input vehicle control command via the vehicle controller from stored acceleration response data; and Forms the negative torque command based on the stored transient acceleration response data.

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