METHOD FOR CONTROLLING VEHICLE OPERATIONS

Abstract

A method for operating a vehicle that includes a propulsion system, wherein the method comprises: Receiving, via a control (15), of vehicle operating parameters and input commands; receiving, via the control (15), of a mode selectable by the driver; Determining a desired future longitudinal torque horizon based on the vehicle operating parameters and the input commands; Determining a desired future yaw rate horizon based on the vehicle operating parameters and input commands; Determining a desired future lateral speed horizon based on vehicle operating parameters and input commands; Determining weighting factors for the desired future longitudinal torque horizon, the desired future yaw rate horizon, and the desired future lateral speed horizon based on the driver-selectable mode; and Control, via the control (15), of the operation of the drive system, based on the desired future longitudinal torque horizon, the desired future yaw rate horizon, the desired future lateral speed horizon and the weighting factors, wherein the receiving, via the control (15), of vehicle operating parameters and Input commands include receiving a vehicle yaw rate, receiving a vehicle longitudinal speed, and receiving an operator command for vehicle steering; and where determining the desired future yaw rate horizon based on the vehicle operating parameters and input commands determines the desired future yaw rate horizon based on the vehicle yaw rate, the vehicle longitudinal speed and the operator command for vehicle steering includes receiving the operator command for vehicle steering, wherein receiving the operator command for vehicle steering includes receiving a front wheel steering angle or a rear wheel steering angle.

Description

INTRODUCTION

[0001] Vehicles consist of components, sensors, subsystems, systems, control units, and associated control routines that can advantageously operate to provide vehicle propulsion, braking, steering, suspension, etc., in response to operator and other input commands. Input commands may include commands related to vehicle acceleration, as well as commands related to vehicle steering and lateral acceleration, which may conflict under certain operating conditions. For example, a commanded change in longitudinal acceleration during a turning maneuver may have priority conflicts that can affect vehicle behavior and driver perception depending on the driver-selected operating mode. If a driver-selected operating mode is Sport Mode or another more aggressive operating mode, the expectation may be that vehicle operation will prioritize longitudinal acceleration.However, if the driver's selected mode is Tour mode or another more relaxed mode, vehicle operation can be expected to prioritize steering to minimize yaw and lateral acceleration.

[0002] Therefore, there may be a need for components, systems, control logic, and methods for controlling vehicle propulsion, braking, steering, and suspension systems in response to operator and other input commands that take into account a driver-selected mode of operation.

[0003] EP 2 911 907 B1 relates to a method for operating a drivetrain of a motor vehicle. Furthermore, the invention relates to a system for operating a drivetrain of a motor vehicle. DE 10 2014 219 899 A1 describes a vehicle braking / driving force control device for ensuring driving stability of a vehicle with priority when a wheel slip occurs for generating a braking / driving force while controlling a plurality of movements.

[0004] DE 10 2018 207 807 A1 relates to a method for dynamic speed control of a motor vehicle when negotiating curves. According to the invention, it is possible, among other things, to realize automated and comfortable negotiation of curves in cruise control mode. Furthermore, the present invention relates to a correspondingly configured system arrangement. DE 10 2008 035 115 A1 describes a system and method for detecting a road curve as a vehicle approaches the curve, for automatically providing road curvature information, and for controlling the vehicle speed. The system uses a positioning device and a map database to determine the vehicle's position.

[0005] DE 10 2016 215 046 A1 describes a method for assisting a driver when cornering a motor vehicle or for automatically carrying out the cornering, comprising the steps: - specifying a target longitudinal acceleration value and / or a target lateral acceleration value depending on a determined occupant preference of an occupant of the motor vehicle, - determining at least one curve parameter which relates to a course of a curve or group of curves which is expected to be traveled in the future.

[0006] DE 10 2008 010 494 A1 describes a command interpreter for a vehicle stability enhancement system that uses a three-degree-of-freedom vehicle model employing nonlinear suspension and tire characteristics to calculate stability commands.

[0007] DE 10 2005 021 819 A1 relates to a system and method for controlling a motor vehicle with a lateral acceleration sensor that provides a lateral acceleration signal, a yaw rate sensor that provides a yaw rate signal, and a safety system. The safety system and the sensors are connected to a controller. DESCRIPTION

[0008] The object of the invention is to make an operating mode selected by the driver more user-friendly. This object is achieved by the subject matter of independent claim 1. Further developments can be found in the subclaims.

[0009] The concepts described here relate to the calculation of desired future longitudinal horizons in terms of torque or acceleration and desired future lateral horizons in terms of yaw rate and lateral velocity, and their use in response to driver-selectable modes. In the longitudinal direction, driver inputs of pedal and brake position, as well as drivability metrics, are used to calculate the desired future torque trajectory. In the lateral direction, the front and rear steering angles can be used with a bicycle model to derive the trajectories. The trajectories are used in a vehicle motion controller that uses weighting to balance competing demands and deliver performance consistent with a selected driver mode, such as a touring mode, a sport mode, an off-road mode, a trailering mode, etc.

[0010] One aspect of the disclosure includes a system and associated method for operating a vehicle, including monitoring vehicle operating parameters such as vehicle speed, steering angle, weight, etc., and input commands such as operator inputs to an accelerator pedal, a brake pedal, a steering wheel, and / or an advanced driver assistance system (ADAS). A desired future horizon for longitudinal torque is determined based on vehicle speed and an operator input to an accelerator pedal; a desired future horizon for yaw rate is determined based on a commanded steering angle; and a desired future horizon for lateral velocity is determined based on the commanded steering angle and a lateral velocity of the vehicle.Weighting factors are determined based on a driver-selectable mode, and vehicle operation is controlled based on the desired future longitudinal torque horizon, the desired future yaw rate horizon, the desired future lateral velocity horizon, and the weighting factors.

[0011] Another aspect of the disclosure includes receiving, via the controller, a vehicle speed and an operator command for vehicle acceleration or deceleration and determining the desired future longitudinal torque horizon based on the vehicle speed and the operator command for vehicle acceleration or deceleration.

[0012] Another aspect of the disclosure includes receiving a vehicle yaw rate, receiving a vehicle longitudinal velocity, and receiving an operator command for vehicle steering; and determining the desired future yaw rate horizon based on the vehicle yaw rate and the operator command for vehicle steering.

[0013] Another aspect of the disclosure includes receiving the operator command for vehicle steering in the form of a front wheel steering angle or a rear wheel steering angle.

[0014] Another aspect of the disclosure includes receiving a vehicle lateral velocity, receiving a vehicle longitudinal velocity, and receiving an operator command for vehicle steering; and determining the desired future lateral velocity horizon based on the vehicle lateral velocity and the operator command for vehicle steering.

[0015] Another aspect of the disclosure includes determining the weighting factors for tracking the desired future longitudinal torque horizon, the desired future yaw rate horizon, and the desired future lateral velocity horizon based on the driver selectable mode and vehicle operating parameters.

[0016] Another aspect of the disclosure includes controlling operation of the propulsion system to minimize a difference between the desired future longitudinal torque horizon and the operator command for torque related to either vehicle acceleration or vehicle deceleration, and to minimize a difference between the desired future yaw rate horizon and a predicted yaw rate and a desired future lateral velocity horizon and a predicted velocity.

[0017] Another aspect of the disclosure includes controlling operation of the propulsion system to minimize a difference between the desired future longitudinal velocity horizon and the operator command for one of vehicle acceleration or vehicle deceleration, and minimizing a difference between the desired future yaw rate horizon and a predicted yaw rate and a desired future lateral velocity horizon and a predicted torque.

[0018] Another aspect of the disclosure includes receiving a vehicle speed and receiving an input command from an advanced driver assistance system (ADAS) for a vehicle speed, a vehicle acceleration, or a vehicle deceleration; and determining the desired future longitudinal torque horizon based on the vehicle speed and the input command from the ADAS for a vehicle acceleration or a vehicle deceleration.

[0019] The above features and advantages, as well as other features and advantages of the present teachings, are readily apparent from the following detailed description of some of the preferred embodiments and other embodiments for carrying out the present teachings, as defined in the appended claims, when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE CHARACTERS

[0020] One or more embodiments will now be described by way of example with reference to the accompanying figures, in which: Fig. 1 schematically shows a plan view of a vehicle according to the disclosure. Fig. 2 to 7 schematically show flow diagrams associated with a computer-executable control routine for controlling the operation of an embodiment of the system described with reference to Fig. 1 described vehicle in accordance with the disclosure. Fig. 8 graphically shows the shaping of the longitudinal torque horizon with a map and a transient map according to the disclosure. Fig. 9 graphically shows various horizontal responses of lateral motion (yaw rate or lateral velocity) according to aggressive or normal or conservative driver mode, which can be achieved by setting various filter parameters or cost function weights according to the disclosure. Fig. Figure 10 graphically shows different gain settings corresponding to different horizon responses.

[0021] It should be understood that the accompanying figures are not necessarily to scale and represent a somewhat simplified representation of various preferred features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes. Details associated with such features will be determined in part by the particular intended application and environment of use. DETAILED DESCRIPTION

[0022] The components of the disclosed embodiments, as described and illustrated herein, can be arranged and implemented in a variety of different configurations. Therefore, the following detailed description is not intended to limit the scope of the claimed disclosure, but is merely representative of possible embodiments thereof. Moreover, while numerous specific details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed herein, some embodiments may be practiced without some of these details. Furthermore, for the sake of clarity, detailed descriptions of certain technical matters which are common knowledge in the related art have been omitted in order not to unnecessarily obscure the disclosure.Furthermore, the disclosure as shown and described herein may be practiced without any element not specifically disclosed herein.

[0023] Fig. 1 schematically illustrates, in accordance with the embodiments disclosed herein, a vehicle 100 disposed on a driving surface, the vehicle 100 having operating systems including a propulsion system 10, a steering system 16, and a wheel braking system 26, all arranged to transmit traction, braking (or retarding) force, and steering force to one or more vehicle wheels 20. In some embodiments, the vehicle 100 further includes an advanced driver assistance system (ADAS) 40, which may be coupled to a spatial monitoring system 30 and a navigation system 32. The propulsion system 10, the wheel braking system 26, and the steering system 16 are arranged and controllable to transmit traction, braking, and steering force, respectively, to one or more vehicle wheels 20 in response to input commands, such asOperator inputs to an accelerator pedal 19, a brake pedal 18, a steering wheel 12, and / or input commands generated by the ADAS 40, which may be controlled via an operator interface device 17. The operation of the vehicle 100, including the aforementioned operating systems, is controlled by a plurality of controllers executing control routines, collectively referred to hereinafter as controller 15. As used herein, the term "vehicle" refers, without limitation, to vehicle platforms such as passenger cars, commercial vehicles, industrial vehicles, tracked vehicles, off-road and all-terrain vehicles (ATVs), motorcycles, agricultural equipment, watercraft, aircraft, etc. Other operator requests may be generated based on operator inputs to a transmission range selector, etc.

[0024] The drive system 10 may be configured as an internal combustion engine coupled to a stepped or continuously variable transmission controlled by a powertrain controller to generate traction in response to operator demands and input commands, in one embodiment. Alternatively, the drive system 10 may be configured as a hybrid powertrain system, where traction is generated by either an internal combustion engine or one or more electric machines controlled by a powertrain controller to generate traction in response to operator demands and input commands.Alternatively, the drive system 10 may be configured as an electric drive system in which the tractive effort is generated by one or more electric machines controlled by a powertrain controller to generate the tractive effort in response to operator demands and input commands.

[0025] The steering system 16 includes the steering wheel 12 and a steering actuator 14. As illustrated, the steering system 16 is configured to control the steering only at the front wheels of the vehicle 100. Alternatively, the steering system 16 may be configured to control the steering in both the front and rear wheels of the vehicle 100, as represented by element 13. Alternatively, the steering system 16 may be configured to control the steering only at the rear wheels of the vehicle 100.

[0026] The wheel braking system 26 includes wheel speed sensors 22 and wheel brakes 24 to mechanically brake the vehicle wheels 20. When the vehicle 100 is configured as a hybrid vehicle or an electric vehicle, the mechanical braking force provided by the wheel braking system 26 may be supplemented by regenerative braking force provided by the generation of reactive torque by one or more electric machines.

[0027] The vehicle 100 and the driving surface define a spatial area in the form of a three-dimensional coordinate system 50 comprising a longitudinal axis (X) 51, a transverse axis (Y) 52, and a vertical axis (Z) 53. The longitudinal axis 51 is defined by a longitudinal axis of the vehicle 100, the transverse axis 52 is defined by a transverse axis of the vehicle 100, and the vertical axis 53 is defined to be orthogonal to a plane defined by the longitudinal axis 51 and the transverse axis 52.

[0028] When used, the navigation system 32 uses information from a GPS (Global Positioning System) sensor 36 and an IMU (Inertial Measurement Unit) 34. In one embodiment, the GPS sensor 36 is configured as a GNSS (Global Navigation Satellite System) sensor. The IMU 34 is an electronic device that uses one or more combinations of accelerometers, gyroscopes, and magnetometers to measure and report the specific force, angular velocity, yaw, and orientation of the vehicle 100.

[0029] The ADAS 40 is arranged to provide operator assistance functions by controlling one of the operating systems, i.e., one or more of the propulsion system 10, the steering system 16, the wheel braking system 26, in conjunction with or without direct interaction of the vehicle operator via the operator interface device 17. The ADAS 40 includes a controller and one or more subsystems that provide operator assistance functions, including one or more of a fully autonomous driving system, an adaptive cruise control (ACC) system, a lane keeping control (LKY) system, a lane departure control (LCC) system, an autonomous braking / collision avoidance system, and / or other systems configured to command and control autonomous vehicle operation separately from or in conjunction with operator requests.The ADAS 40 can interact with and access an on-board map database to plan the route and control the operation of the vehicle 100 via the lane keeping system, the lane centering system, and / or other systems configured to command and control autonomous vehicle operation. Autonomous operation commands can be generated to control the ACC system, the LKY system, the LCC system, the autonomous braking / collision avoidance system, and / or the other systems. Vehicle operation can occur in response to operator requests and / or the input commands generated by the ADAS 40 or other autonomous vehicle requests. Vehicle operation includes acceleration, braking, steering, cruising, coasting, and idle.

[0030] The on-board navigation system 32 may include a computer-readable storage device or medium (memory) containing a digitized road map and communicating with the ADAS 40. The concepts described herein may be implemented on various systems that may benefit from information obtained by an embodiment of the spatial monitoring system 30 in a manner described herein.

[0031] The term "controller" and related terms such as microcontroller, control unit, processor, and similar terms refer to one or various combinations of application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), electronic circuits, central processing units, e.g., microprocessors, and associated non-transitory memory components in the form of memory and storage devices (read-only, programmable read-only, random access, hard disk drives, etc.). The non-transitory memory component is capable of storing machine-readable instructions in the form of one or more software or firmware programs or routines, combinational logic circuits, input / output circuits and devices, signal conditioning and buffer circuits, and other components that can be accessed by one or more processors to provide a described functionality.Input / output circuits and devices include analog-to-digital converters and related devices that monitor inputs from sensors, where such inputs are monitored at a preset sampling frequency or in response to a triggering event. Software, firmware, programs, instructions, control routines, code, algorithms, and similar terms refer to sets of instructions executable by controllers, including calibrations and look-up tables. Each controller executes control routine(s) to provide desired functions. The routines may be executed at regular intervals, such as every 100 microseconds during operation. Alternatively, the routines may be executed in response to the occurrence of a triggering event.Communication between controllers, actuators, and / or sensors can occur via a direct-wired point-to-point connection, a networked communication bus connection, a wireless connection, or any other suitable communication link. Communication includes the exchange of data signals in any suitable form, e.g., electrical signals over a conductive medium, an electromagnetic signal over air, optical signals over fiber optics, and the like. The data signals can include discrete, analog, or digitized analog signals representing inputs from sensors, actuator commands, and communication between controllers. The term "signal" refers to a physically perceptible indicator that conveys information and can be any suitable waveform (e.g.,Any physical signal (electrical, optical, magnetic, mechanical, or electromagnetic) such as direct current, alternating current, sine wave, triangular wave, square wave, vibration, and the like, that can propagate through a medium. A parameter is defined as a measurable quantity that represents a physical property of a device or other element that is detectable using one or more sensors and / or a physical model. A parameter can have a discrete value, e.g., either "1" or "0," or it can have a continuously variable value.

[0032] With reference to Fig. 2 ff., a control routine 200 is now described, which illustrates a methodology, a system, and an associated structure for controlling the operation of an embodiment of the propulsion system 10 for the vehicle 100 described with reference to Fig. 1, in the form of schematic flow diagrams. The control routine 200 includes a Driver Command Interpreter (DCI) 210, a Cost Function routine 220, and a Vehicle Motion Controller (VMC) 230. Operator inputs, vehicle operating parameters, and other input commands are provided to the DCI 210, which generates horizon terms for longitudinal acceleration, yaw rate, and lateral velocity. The vehicle operating parameters and other inputs are provided to the Cost Function routine 220, which generates weighting factors 225 related to the longitudinal acceleration, yaw rate, and lateral velocity and driver-selectable modes.The VMC 230 evaluates the horizon terms for the longitudinal acceleration, the yaw rate, and the lateral velocity with respect to the weighting factors 225 corresponding to the longitudinal acceleration, the yaw rate, and the lateral velocity, and based thereon determines actuator commands 240 for controlling the operation of the drive system 10. This process will now be described in detail.

[0033] The control routine 200 receives input commands via the controller 15, including operator inputs in the form of accelerator / brake pedal commands 201, a regenerative braking torque request 202, a steering wheel angle 203, and a rear wheel angle 204.

[0034] The control routine 200 also receives input commands via the controller 15, including inputs in the form of an ADAS command 205 for embodiments of the vehicle 100 so equipped, such as a vehicle speed command for an adaptive cruise control system. In one embodiment, the ADAS command 205 may also be a horizon planned for the near future. Examples of horizons could be a speed-velocity profile (longitudinal and lateral), a longitudinal torque profile, and a yaw rate / lateral velocity profile. However, the time span of the ADAS horizon will most likely differ from the time span of the desired future horizons described herein and would therefore need to be resampled and possibly converted from one unit to another. For example, a speed profile may be converted into horizons for torque, yaw rate, and lateral velocity.

[0035] The control routine 200 also receives, via the controller 15, vehicle operating conditions 206 in the form of vehicle mass, road grade, vehicle speed, and the driver-selectable mode. Examples of driver-selectable modes include Tour mode, Sport mode, Tow / Haul mode, AWD (all-wheel drive), Off-Road, etc. Tour mode is intended for everyday driving to optimize fuel economy and ride quality. Sport mode is intended for more aggressive acceleration behavior to achieve a sporty driving behavior. Tow / Haul mode is designed to improve driving behavior when towing a trailer or a heavy load, e.g., by adjusting the transmission shift behavior to minimize the number of gear shifts, etc. AWD mode is designed to improve normal driving behavior on paved roads covered with water, snow, or ice.Off-road mode is designed to adjust the operation of the powertrain, brakes, and steering to improve traction and maneuverability in off-road conditions.

[0036] The input commands and operating states of the vehicle are provided as inputs to a Driver Command Interpreter (DCI) 210, which is configured to plan the future behavior of the vehicle over a defined period of time referred to as horizons. The planned vehicle behaviors determined by the DCI 210 include a desired future longitudinal torque horizon 212, a desired future yaw rate horizon 214, and a desired future lateral velocity horizon 216. The DCI 210 also determines a variety of system and operational constraints 218 based thereon. Additional details of the operations of the DCI 210 will be described with reference to the Fig. 3 to 7.

[0037] The term 'horizon' is used to describe an estimated or predicted behavior for a subject vehicle over a predefined period of time for a particular parameter, e.g., longitudinal torque, yaw rate, lateral velocity, etc. The derivation of a horizon can be determined based on a predefined set of vehicle parameters, such as an effective road load acting on the vehicle, from nominal road load forces constructed using a road load equation with coefficients representing kinetic friction, rolling friction, and aerodynamic drag, in conjunction with forces acting on the subject vehicle due to mass and gravity.

[0038] Fig. Figure 3 schematically illustrates process 310, which is a first embodiment of a process for determining the desired future longitudinal torque horizon 212 based on the vehicle operating state 206, the vehicle speed, and the operator input in the form of the accelerator / brake pedal commands 201, which are input to a response map (RM) 311 to determine a target longitudinal torque x(k). Alternatively, the RM 311 may also determine a target longitudinal acceleration.

[0039] The target longitudinal torque x(k) is input to an iterative loop 312 that uses a transient response map (tRM) 314 to determine a target longitudinal torque y(k+1) over a horizon of time length M 317 based on inputs of the longitudinal torque x(k), the vehicle speed v(k+i-1), and the target longitudinal torque y(k+i-1) 313, where M represents a time period defined by the horizon. The transient map 314 determines a differential torque dTq(k+i-1) based on the desired longitudinal torque x(k), the vehicle speed v(k), and the desired longitudinal torque over a previous iteration y(k+i-1). The differential torque dTq(k+i-1) is combined with the target longitudinal torque over the previous iteration y(k+i-1) (block 315) to determine the target longitudinal torque y(k+1) over the horizon of time length M 317. The iteration loop 312 then updates the vehicle speed v(k+1) (block 316) and begins the next iteration.

[0040] The RM 311 converts the driver's acceleration and deceleration commands into vehicle drivability targets to obtain a resulting desired vehicle force. Drivability targets, such as those described by vehicle-calibrated response maps and associated transient response maps, and vehicle parameters such as road load coefficients, effective road load, and nominal road load forces, are incorporated into the final speed horizon profile. In some implementations, braking force requests may also be incorporated into the formulation. The RM 311 can, in practice, be reduced to a table that may contain a stored, controller-accessible map file mapping a sequence of vehicle speeds and vehicle acceleration values ​​with a corresponding sequence of commanded or desired powertrain torque outputs.Alternatively, in practice, the RM3211 can be reduced to a table that may contain a map file stored in memory and accessible to the controller, mapping a sequence of vehicle speeds and vehicle acceleration values ​​with a corresponding sequence of commanded or desired acceleration outputs.

[0041] Raw pedal travel data in the form of a desired acceleration is used to look up a driver torque request in the map file related to the current vehicle speed and the current accelerator pedal position. The driver torque request may be shaped using the transient response map 314, which may be a vehicle-calibrated transient acceleration map. The transient response map 314 may include a memory-stored, controller-accessible acceleration transient response map file. The transient response map 314 may be a lookup table that defines the powertrain torque in transition regions between adjacent powertrain torque output values ​​in the acceleration map file. As a non-limiting example, the transient response map 314 may define an appropriate ramp rate (e.g.,Identify the acceleration or torque change (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 is shaped by incorporating these acceleration / torque ramp rate responses to add curvature to the torque demand profile.

[0042] The target longitudinal torque y(k+1) over the horizon of time length M 317 is fed to an extraction step 318 which identifies a future point of interest of length N (319), where N (319) can be a suitable time length, e.g., 1 ms, 2 ms, 3 ms, 4 ms, 5 ms, 100 ms, 200 ms, 300 ms, 400 ms, etc., as long as the time length N is smaller than the horizon of time length M 317. The extraction step 318 interpolates or otherwise determines the desired future longitudinal torque horizon 212 over the time length N, which is supplied to the VMC 230.

[0043] Fig. 4 schematically illustrates process 320, which is a second embodiment of a process for determining the desired future longitudinal torque horizon 212 based on vehicle operating conditions 206, including vehicle speed and operator input in the form of accelerator / brake pedal commands 201. In this embodiment, response map (RM) 321 is included in iterative loop 322. RM 321 determines a target longitudinal torque x(k), which is input to transient response map (tRM) 324 to determine a target longitudinal torque y(k+1) over a horizon of time length M 327 based on the inputs of longitudinal torque x(k), vehicle speed v(k+i-1), and target longitudinal torque y(k+i-1) 323, where M represents a time period defined by the horizon.The transient response map 324 determines a differential torque dTq(k+i-1) based on the target longitudinal torque x(k), the vehicle speed v(k), and the target longitudinal torque over a previous iteration y(k+i-1). The differential torque dTq(k+i-1) is combined with the target longitudinal torque over the previous iteration y(k+i-1) (block 325) to determine the target longitudinal torque y(k+1) over the horizon of time length M 327. The iteration loop 322 then updates the vehicle speed v(k+1) (block 326) and begins the next iteration. The transient response map 324 is analogous to the transient response map 314 described with reference to FIG. Fig. 3 was described.

[0044] The target longitudinal torque y(k+1) over the horizon of time length M 327 is fed to an extraction step 328 which identifies a future point of interest of length N (329), where N (329) can be a suitable time length, e.g., 1 ms, 2 ms, 3 ms, 4 ms, 5 ms, 100 ms, 200 ms, 300 ms, 400 ms, etc., as long as the time length N is smaller than the horizon of time length M. The extraction step 328 interpolates or otherwise determines the desired future longitudinal torque horizon 212 over the time length N, which is fed to the VMC 230.

[0045] Fig. 5 schematically shows the process 330, which is one embodiment of a process for determining the desired future yaw rate horizon 214 based on the vehicle operating conditions 206, the steering wheel angle 203, and the rear wheel angle 204, where applicable.

[0046] In this embodiment, a desired steady-state yaw rate is determined based on the vehicle's operating conditions 206, the steering wheel angle 203, and the rear wheel angle 204 (block 331). An iterative loop 332 is executed to determine a target yaw rate x(k+1) (block 335) according to the following relationship: y(k+i)=f[x(k),y(k+i−1),…,y(k+i−1−Q),cl,…,cQ∗] where y(k+1) represents the target yaw rate; and c1, ..., cQ are tuned to define a desired dynamic behavior of the vehicle.

[0047] The target yaw rate y(k+1) is extrapolated over a horizon of time length M 337, where M represents a time period defined by the horizon. The iteration loop 332 updates the target yaw rate y(k+1) and begins the next iteration.

[0048] The target yaw rate y(k+1) over the horizon of time length M 337 is fed to an extraction step 338 which identifies a future point of interest of length N (339), where N (339) can be a suitable time length, e.g., 1 ms, 2 ms, 3 ms, 4 ms, 5 ms, 100 ms, 200 ms, 300 ms, 400 ms, etc., as long as the time length N is less than the horizon of time length M 337. The extraction step 338 interpolates or otherwise determines the desired future yaw rate horizon 214 over the time length N, which is supplied to the VMC 230.

[0049] Fig. 6 schematically shows the process 340, which is one embodiment of a method for determining the desired future lateral velocity horizon 216 based on the vehicle operating conditions 206, the steering wheel angle 203, and possibly the rear wheel angle 204.

[0050] In this embodiment, a lateral target speed is determined based on the vehicle operating conditions 206, the steering wheel angle 203, and the rear wheel angle 204 (block 341). An iterative loop 342 is executed to determine a lateral target speed z(k+1) (block 345) according to the following relationship: y(k+i)=f[w(k),z(k+i−1),…,z(k+i−1−Q),cl,…,cQ∗] where z(k+1) represents the lateral target velocity; and c1, ..., cQ are tuned to define a desired dynamic behavior of the vehicle.

[0051] The target lateral velocity z(k+1) is extrapolated over a horizon of time length M 347, where M represents a time period defined by the horizon. The iteration loop 342 updates the vehicle lateral velocity z(k+1) and begins the next iteration.

[0052] The target lateral velocity z(k+1) over the horizon of time length M 347 is fed to an extraction step 348 which identifies a future point of interest of length N(349), where N (349) may be a suitable time length, e.g., 1 ms, 2 ms, 3 ms, 4 ms, 5 ms, 100 ms, 200 ms, 300 ms, 400 ms, etc., as long as the time length N is less than the horizon of time length M 347. The extraction step 348 interpolates or otherwise determines the desired future lateral velocity horizon 216 over the time length N, which is provided to the VMC 230.

[0053] Fig. 7 schematically illustrates process 350, which is one embodiment of a process for consistently determining the desired future yaw rate horizon 214 and the desired future lateral velocity horizon 216 based on the vehicle operating conditions 206, the steering wheel angle 203, and the rear wheel angle 204, where applicable.

[0054] In this embodiment, an iterative loop 352 is executed to determine a target yaw rate x(k+1) (block 353) according to the following relationship: x(k+i)=x(k+i−1)+T{Fyf cos[FS(k)]−Fyr cos[RS(k)]} where Fyf represents the lateral force on the front axle; Fyr represents the lateral force on the rear axle; FS(k) represents the front steering angle; RS(k) represents the rear steering angle; x(k+1) represents the target or desired yaw rate; and c1, ..., cQ are tuned to define a desired dynamic behavior of the vehicle.

[0055] In this relationship, the desired yaw rate x(k+1) is extrapolated over a horizon of time length M 354, where M represents a time period defined by the horizon.

[0056] The target yaw rate x(k+1) over the horizon of time length M 354 is supplied to an extraction step 356 which identifies a future point of interest of length N, where N can be a suitable time length, e.g., 1 ms, 2 ms, 3 ms, 4 ms, 5 ms, 100 ms, 200 ms, 300 ms, 400 ms, etc., as long as the time length N is less than the horizon of time length M. The extraction step 356 interpolates or otherwise determines the desired future yaw rate horizon 214 over the time length N, which is supplied to the VMC 230.

[0057] The iteration loop 352 provides the target yaw rate x(k+1) as input to block 357.

[0058] The vehicle yaw rate x(k+1) from block 353, the vehicle operating states 206, the steering wheel angle 203 and the rear wheel angle 204 are used to determine the target lateral velocity z(k+1) (block 357) according to the following relationship z(k+i)=z(k+i−1)+T{Mvx∗x(k+i−1)+F′yf cos[FS(k)]+F′yr cos[RS(k)]} where M stands for the vehicle mass; vx stands for the vehicle longitudinal speed; Fyf represents the lateral force on the front axle; Fyr stands for the lateral force on the rear axle; and c1, ..., cQ are tuned to define a desired dynamic behavior of the vehicle.

[0059] The target lateral velocity z(k+1) is extrapolated over a horizon of time length M 351, where M represents a time period defined by the horizon. The iteration loop 352 begins the next iteration.

[0060] The target lateral velocity z(k+1) over the horizon of time length M 351 is fed to an extraction step 359 which identifies a future point of interest of length N, where N can be a suitable time length, e.g., 1 ms, 2 ms, 3 ms, 4 ms, 5 ms, 100 ms, 200 ms, 300 ms, 400 ms, etc., as long as the time length N is less than the horizon of time length M 351. The extraction step 359 interpolates or otherwise determines the desired future lateral velocity horizon 216 over the time length N, which is provided to the VMC 230.

[0061] Fig. Figure 8 graphically shows the shaping of the longitudinal torque horizon based on a driver request as a function of time, with torque on the vertical axis 820 and time on the horizontal axis 810. Line 801 shows an unshaped, arbitrary driver torque request in the form of a step input to an accelerator pedal, such as might occur when a driver performs a wide-open throttle maneuver. Line 802 shows the driver-requested torque after being subjected to rate limiting and filtering, as described in the Fig. described, with the horizon indicated by area 804. Line 803 displays the actual powertrain system performance in response to the torque request associated with line 802.

[0062] Fig. Figure 9 graphically shows different horizon responses of lateral movement (yaw rate or lateral velocity) corresponding to the driver modes aggressive 901, normal 902, or conservative 903, with the lateral movement indicated on the vertical axis 920 and time on the horizontal axis 910. The different horizon responses of lateral movement (yaw rate or lateral velocity) can be achieved by setting different filter parameters or cost function weights, such as with respect to Fig. 10 shown.

[0063] Fig. Figure 10 graphically shows various gain settings corresponding to different horizon responses according to the aggressive 1001, normal 1002, or conservative 1003 driver modes, with the gain setting indicated on the vertical axis 1020 and time on the horizontal axis 1010.

[0064] Referring again to Fig. 2, the vehicle operating parameters and other inputs are fed to the cost function routine 220 to generate weighting factors 225 corresponding to longitudinal acceleration, yaw rate, and lateral velocity. Input commands include operator inputs in the form of throttle-brake pedal commands 201, regenerative braking torque requests 202, steering wheel angle 203, rear wheel angle 204, vehicle operating conditions 206 in the form of vehicle mass, road gradient, vehicle speed, and the driver-selectable mode. In each loop, the control routine 200 optimizes a cost function of the following form: Sum_k=0,k=N(TWght_k[Tpred_k−Thorizon_k]2)+ Sum_k=0,k=N(R_Wght_k[R_pred_k−R_Horizon_k]2)+ Sum_k=0,k=N(VyWght_k[Vypred_k−VyHorizon_k]2)+ f(.,.,.) where: TWght_k is the weight at time k for the longitudinal torque horizon, R_Wght_k is the weight at time k for the yaw rate horizon, VyWght_k is the weight at time k for the lateral velocity, Tpred is the predicted longitudinal torque, R is the predicted yaw rate, and Vypred is the predicted lateral velocity.

[0065] The weighting factors 225 are associated with the desired future longitudinal torque horizon 212, the desired future yaw rate horizon 214, and the desired future lateral velocity horizon 216, where the weights Tpred, R, and Vypred correspond to the longitudinal acceleration, yaw rate, and lateral velocity, respectively, and are provided as inputs to the VMC 230. By adjusting the weights in the cost function based on the vehicle's operating conditions, its output can better reflect the driver's desired vehicle behavior.

[0066] The VMC 230 evaluates the desired future longitudinal torque horizon 212, the desired future yaw rate horizon 214, and the desired future lateral velocity horizon 216 with respect to the weighting factors 225 corresponding to the longitudinal acceleration, the yaw rate, and the lateral velocity, and, based thereon, determines an actuator command 240 for controlling the operation of the drive system 10.

[0067] Referring again to Fig.2, the VMC 230 includes executable routines for performing a model-based control analysis to determine an actuator command 240 for controlling the operation of the propulsion system 10 to achieve the driver's desired acceleration command and / or deceleration command 201. To perform this analysis, the VMC 230 aggregates and analyzes the desired future longitudinal torque horizon 212, the desired future yaw rate horizon 214, the desired future lateral velocity horizon 216, and the plurality of system and operational constraints 218. The VMC 230 may store a model of the vehicle, such as a two-track bicycle model in which the torque commands, yaw rate, and lateral velocity are the controlled variables. The model may be derived using first principles or determined experimentally, or a combination of both.Optimization techniques can be used to calculate torque commands that minimize tracking error while considering vehicle constraints. Torque control can consider the error between the torque request and the commanded controller torque in a closed-loop control system to minimize a difference between the desired torque horizon and the predicted torque, and to minimize a difference between a desired yaw rate and a desired lateral velocity and a predicted yaw rate and predicted velocity. A desired future trajectory can be used by the VMC 230 to optimize actuator commands based on desired future target trajectories and measurements.

[0068] The concepts presented here include calculating desired future longitudinal horizons for torque or acceleration and desired future lateral horizons for yaw rate and lateral velocity, and using them to achieve expected driver modes. In the longitudinal direction, driver inputs of pedal and brake position and drivability metrics are used to calculate the desired future torque trajectory. In the lateral direction, front and rear steering angles are used with a bicycle model to derive the trajectories. The trajectories are used in a vehicle motion controller that leverages the trade-off of competing demands to deliver performance consistent with a selected driver mode. This involves determining the desired future longitudinal torque horizon using the response map (RM) and the transient response map based on driver and regenerative braking demands.

[0069] The concepts described here involve calculating the desired future lateral yaw rate and lateral velocity based on a simplified bicycle model and the front and rear steering angles.

[0070] The concepts described here involve using the longitudinal and lateral horizons and balancing their costs in a vehicle motion control system to deliver vehicle behavior consistent with a selected driver mode.

[0071] The concepts described here allow for variable sampling time of the horizons to maximize accuracy while reducing storage and communication requirements.

[0072] The concepts described here include the determination of the desired future longitudinal acceleration horizon using a pedal acceleration map and a transient response map.

[0073] The concepts described here involve determining and using the desired future longitudinal torque horizon, the desired future yaw rate horizon, the desired future lateral velocity horizon, and the vehicle constraints in a vehicle motion controller to provide vehicle behavior consistent with the expected driver mode response and manage competing longitudinal and lateral acceleration objectives.

[0074] The block diagrams in the flowcharts illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the block diagrams may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function(s). It should also be understood that each block in the block diagrams and / or flowchart representations, and combinations of blocks in the block diagrams and / or flowchart representations, may be implemented by dedicated-function hardware-based systems that perform the specified functions or acts, or by combinations of dedicated-function hardware and computer instructions.These computer program instructions may also be stored in a computer-readable medium that can instruct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture that includes instruction means that implement the function / action specified in the flowchart and / or block diagram block or blocks.

[0075] The detailed description and the drawings or figures are supportive and descriptive of the present teachings, but the scope of the present teachings is defined solely by the claims. While some of the preferred embodiments and other embodiments for carrying out the present teachings have been described in detail, various alternative designs and embodiments exist for carrying out the present teachings defined in the appended claims.

Claims

[1] A method of operating a vehicle including a propulsion system, the method comprising: Receiving, via a controller (15), vehicle operating parameters and input commands, Receiving, via the controller (15), a driver-selectable mode; Determining a desired future longitudinal torque horizon based on the vehicle operating parameters and the input commands; Determining a desired future yaw rate horizon based on the vehicle operating parameters and the input commands; Determining a desired future lateral velocity horizon based on the vehicle operating parameters and the input commands; Determining weighting factors for the desired future longitudinal torque horizon, the desired future yaw rate horizon, and the desired future lateral velocity horizon based on the driver-selectable mode; and Controlling, via the controller (15), the operation of the drive system based on the desired future longitudinal torque horizon, the desired future yaw rate horizon, the desired future lateral velocity horizon and the weighting factors, wherein receiving, via the controller (15), vehicle operating parameters and Input commands include receiving a vehicle yaw rate, receiving a vehicle longitudinal velocity, and receiving an operator command for vehicle steering; and wherein determining the desired future yaw rate horizon based on the vehicle operating parameters and the input commands comprises determining the desired future yaw rate horizon based on the vehicle yaw rate, the vehicle longitudinal speed and the operator command for the vehicle steering, wherein receiving the operator command for the vehicle steering comprises receiving a front wheel steering angle or a rear wheel steering angle. [2] The method of claim 1, wherein receiving, via the controller (15), vehicle operating parameters and input commands comprises receiving a vehicle speed and receiving an operator command for one of vehicle acceleration or deceleration; and wherein determining the desired future longitudinal torque horizon based on the vehicle operating parameters and the input commands comprises determining the desired future longitudinal torque horizon based on the vehicle speed and the operator command for one of vehicle acceleration or deceleration. [3] The method of claim 1, wherein receiving, via the controller (15), vehicle operating parameters and input commands comprises receiving a vehicle lateral velocity, receiving a vehicle longitudinal velocity, and receiving an operator command for vehicle steering; and wherein determining the desired future lateral velocity horizon based on the vehicle operating parameters and the input commands comprises determining the desired future lateral velocity horizon based on the vehicle lateral velocity, the vehicle longitudinal velocity, and the operator command for vehicle steering. [4] The method of claim 1, further comprising determining the weighting factors for tracking the desired future longitudinal torque horizon, the desired future yaw rate horizon, and the desired future lateral velocity horizon based on the driver selectable mode and the vehicle operating parameters. [5] The method of claim 1, wherein controlling, via the controller (15), operation of the drive system based on the desired future longitudinal torque horizon, the desired future yaw rate horizon, the desired future lateral velocity horizon, and the weighting factors comprises controlling operation of the drive system to minimize a difference between the desired future longitudinal torque horizon and an operator command for vehicle acceleration or vehicle deceleration, and to minimize a difference between the desired future yaw rate horizon and a predicted yaw rate and a desired future lateral velocity horizon and a predicted velocity. [6] The method of claim 1, wherein receiving, via the controller (15), vehicle operating parameters and input commands comprises receiving a vehicle speed and receiving an input command from an advanced driver assistance system, ADAS, for either vehicle acceleration or vehicle deceleration; and wherein determining the desired future longitudinal torque horizon based on the vehicle operating parameters and the input commands comprises determining the desired future longitudinal torque horizon based on the vehicle speed and the input command from the ADAS for one of vehicle acceleration or vehicle deceleration.

Images