Feedforward compensation for managing longitudinal disturbances during braking-steering.

Abstract

Feedforward compensation for managing longitudinal disturbances during braking-steering. Several illustrative variations may include a system and method for controlling vehicle deceleration while implementing braking-steering functionality. This system and method may include providing a feedforward gain on the vehicle's propulsion torque to achieve or maintain a target longitudinal acceleration and replicate the behavior of a vehicle not using braking-steering. The system may manipulate the vehicle's propulsion to manage longitudinal acceleration and velocity disturbances during braking-steering.

Description

Technical Field

[0001] This disclosure generally relates to the fields of steering, braking and propulsion systems. Background Technology

[0002] Vehicles typically include a steering system, which may include an electronic power steering system incorporating either steer-by-wire or brake-steering technology. When a steering input is applied, a vehicle with an operating steering system can maintain a constant speed. In a brake-steering scenario, applying the brakes to steer the vehicle causes it to decelerate. This behavior may be undesirable to the driver. Summary of the Invention

[0003] Several illustrative variations may include systems that use vehicle brakes to steer the vehicle. In such systems, the brake-steering function may cause the vehicle to decelerate undesirably. A system and method for controlling vehicle deceleration while implementing brake-steering may include providing a feedforward gain on the vehicle's propulsion torque to achieve or maintain a target longitudinal acceleration and replicate the behavior of a vehicle without brake-steering.

[0004] A system and method for controlling vehicle speed and acceleration while performing braking-steering functions may include providing a powertrain torque request on the vehicle's propulsion torque to compensate for braking, while achieving or maintaining a target longitudinal acceleration and replicating the behavior of a normally operating vehicle. The system can manipulate the vehicle's propulsion to manage longitudinal acceleration and speed disturbances during braking-steering.

[0005] Other illustrative variations within the scope of this invention will become apparent from the detailed description provided below. It should be understood that while the detailed description and specific examples disclose variations of the invention, they are intended for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0006] Examples of variations within the scope of the invention will be more fully understood from the detailed description and accompanying drawings, wherein:

[0007] Figure 1 An illustrative variation of the block diagram depicting a system and method for managing longitudinal disturbances during braking-steering; and

[0008] Figure 2 An illustrative variation of the block diagram depicts a system and method for managing longitudinal disturbances during braking and steering. Detailed Implementation

[0009] The following description of the variations is merely illustrative in nature and is by no means intended to limit the scope, application, or use of the invention.

[0010] In several illustrative variations, the vehicle may include a steering system. In such cases, the steering system may be manually operable by the driver via a steering interface, autonomously operable by an autonomous steering system, or operable as a combination of autonomous and manual steering, wherein the steering system is configured to simultaneously receive and interpret steering inputs from the driver, the autonomous steering system, or both. In several illustrative variations, the steering interface may include a handwheel, joystick, trackball, slider, throttle, button, toggle switch, lever, touchscreen, mouse, or any other known user input device.

[0011] In several illustrative variations, the vehicle may include a steering system comprising a steering interface and a steerable propulsion system, such as, but not limited to, a steering wheel and road wheels. The steering system may be of the steer-by-wire type, wherein physical mechanisms do not mechanically transmit manipulation of the steering interface to the steering propulsion system, and wherein manipulation of the steering interface affects associated manipulation of the steerable propulsion system via communication with electronic devices such as, but not limited to, sensors, transceivers, and electrically actuated actuators. According to some variations, the steer-by-wire system may include at least one road wheel actuator and at least one handwheel actuator operably communicating with each other via the steer-by-wire system or controller. The steer-by-wire system may include a road wheel actuator system operably communicating with the handwheel actuator system, wherein rotation of the vehicle's steering wheel or handwheel is translated into actuation of the road wheel actuator system, causing the vehicle wheels to turn.

[0012] The handwheel actuator assembly may include a steering wheel, a handwheel actuator (such as an electric motor), and a handwheel angle sensor. The handwheel actuator assembly may be configured and arranged to transmit handwheel angle and positioning to a road wheel actuator assembly, which includes at least one steering actuator configured and arranged to pivot or rotate a road wheel.

[0013] In several illustrative variations, the vehicle may include an electronic braking system configured and arranged to apply braking pressure or force to any number of road wheels based on driver handwheel input to decelerate or stop the vehicle. The electronic braking system may operatively communicate with the steer-by-wire system, the handwheel actuator assembly, and the road wheel actuator assembly via at least one controller. The controller may implement any number of systems, including algorithms, for monitoring and controlling propulsion, steering, and braking. According to some variations, the electronic braking system may be used to apply differential braking pressure or force to multiple wheels to enable lateral movement of the vehicle in the event of a failure in a portion of the steer-by-wire system—such as an operative disconnection between the wheel actuator assembly and the road wheel actuator assembly.

[0014] In several illustrative variations, the electronic braking system may utilize a brake-steering system including a brake-steering algorithm that transmits braking force requests based on driver steering inputs, including steering angle, steering rate, and steering torque, to the individual wheels to steer the vehicle. The brake-steering algorithm can transmit braking force requests when the system detects a road wheel actuator malfunction or stoppage causing the steering rack to fail to output power. Alternatively, the brake-steering algorithm can transmit braking force requests when the system detects a handwheel actuator malfunction or stoppage.

[0015] In some variations, in the event of a loss of power or complete failure of the steer-by-wire system, including the handwheel actuator and road wheel actuator, the brake-steering system can be controlled by an external domain controller configured and arranged to perform brake-steering functionality. Brake-steering functionality may affect vehicle acceleration and speed, for example, but not limited to, longitudinal disturbances.

[0016] A system for managing longitudinal disturbances in a vehicle may include monitoring a braking force request commanded to steer the vehicle during brake-steering functionality. The braking force request can be translated into braking force or braking torque acting on the vehicle, which can be used to calculate the longitudinal acceleration disturbance caused by brake-steering. The driver's intention regarding longitudinal acceleration can be determined based on information received from engine, transmission, and accelerator pedal positioning. A feedforward gain strategy for the propulsion torque can be implemented based on the magnitude of the pressure applied by the driver in conjunction with the brake-steering intention. As a non-limiting example, if a constant longitudinal velocity is desired, the magnitude of the propulsion torque request can be equal to the braking torque. If it is determined that the driver wants to decelerate or accelerate the vehicle, the feedforward command can be adjusted accordingly. According to some embodiments, the system dynamics of the powertrain, drivetrain, and vehicle may require the application of lead or lag filters to the command. As a non-limiting example, in heavy braking applications, it may be physically impossible to maintain the desired longitudinal state, and given the capabilities of its propulsion system relative to its braking system, feedforward longitudinal compensation should achieve the best possible performance.

[0017] As a non-limiting example, in a vehicle traveling along a road where the steering actuator within the vehicle has failed, the brake-steering function can be used as a strain mechanism for lateral control of the vehicle. If the vehicle enters a curve or turn on the road, the brake-steering function applies braking pressure or force to steer the vehicle. The system can calculate the feedforward propulsion torque request based on the braking pressure command and the driver's intention regarding longitudinal acceleration. The system can allow the vehicle to maintain the desired longitudinal acceleration as interpreted by the driver.

[0018] A system for managing longitudinal disturbances in a vehicle can be implemented on any number of controllers within the vehicle environment during online steering operation or road wheel actuator failure, such as, but not limited to, domain controllers or actuator controllers, including brake electronic control units and steering handwheel actuators.

[0019] A system for managing longitudinal disturbances in a vehicle can be implemented in vehicles with conventional power steering or drive-by-wire, vehicles designed for human operation, or autonomous vehicles. A system for managing longitudinal disturbances in a vehicle can be implemented in vehicles with a single-axle drive front- or rear-mounted internal combustion engine, vehicles with a dual-axle drive internal combustion engine, vehicles with a single-axle drive front- or rear-mounted electric propulsion system, vehicles with a dual-axle drive electric propulsion system, and vehicles with four electric propulsion systems that independently control the torque of all four wheels.

[0020] According to one variant, the system for managing longitudinal disturbances in a vehicle can be implemented on a powertrain control module that receives information from the electronic braking system and the electronic steering system to determine the need to manage longitudinal disturbances in the vehicle when the brake-steering function is activated.

[0021] Figures 1-2 This is for illustrative purposes only. The functionality of various systems or algorithms can be implemented by one or more controllers located anywhere in the vehicle. One or more electronic processors can use and execute one or more algorithms to accomplish the methods, actions, and functions described herein.

[0022] Figure 1An illustrative variation of the block diagram depicting a system and method for managing longitudinal disturbances in a vehicle during braking-steering is provided, which may include a longitudinal feedforward compensation module 120 configured and arranged to transmit a propulsion torque request 122 to the propulsion system in the vehicle. The longitudinal feedforward compensation module 120 may receive a braking command 118 from a brake-steering module 110. The longitudinal feedforward compensation module 120 may additionally receive a desired longitudinal acceleration request 116 from a longitudinal kinematics motion controller 112. The longitudinal kinematics motion controller 112 may receive a desired vehicle speed request 114 from a driver intent calculation module 102. The driver intent calculation module 102 may receive vehicle data, such as, but not limited to, vehicle speed 104, accelerator pedal positioning data 106, and powertrain state data 108. In this manner, vehicle speed data 104, accelerator pedal positioning data 106, and powertrain status data 108 can be combined with braking commands 118 from the brake-steering system 110 to generate a propulsion torque request 122. This propulsion torque request 122 can be transmitted to the propulsion system within the vehicle utilizing brake-steering, so that the acceleration during vehicle propulsion can be modified to maintain the desired longitudinal acceleration and speed as interpreted by the driver.

[0023] Figure 2 An illustrative variation of the block diagram depicting a system and method for managing longitudinal disturbances in a vehicle during braking-steering is provided, which may include a longitudinal feedforward compensation module 220 configured and arranged to generate at least one thrust torque request based on a desired longitudinal acceleration and at least one braking command. The system may include receiving a desired longitudinal acceleration 216, calculating a target force 224, receiving at least one braking command 218 from the braking-steering system, and generating a target thrust force 226 to be transmitted to a vehicle speed-dependent feedforward gain module 228. The target force 224 may be an estimated total force applied to the vehicle to achieve the desired acceleration. The target thrust force 226 may be a required estimated thrust force to counteract the forces associated with vehicle braking so that the desired longitudinal acceleration can be achieved. Vehicle speed data 224 may be transmitted to the vehicle speed-dependent feedforward gain module 228. The vehicle speed-dependent feedforward gain module 228 may generate a thrust torque request 222. The system may include transmitting at least one propulsion torque request 222 to the propulsion system within the vehicle and manipulating the vehicle propulsion system to manage longitudinal disturbances, such as, but not limited to, reducing the deceleration of the vehicle during braking-steering.

[0024] The following description of variations is merely illustrative of components, elements, actions, products, and methods considered to be within the scope of this invention, and is not intended in any way to limit such scope by specific disclosures or non-expressive statements. In addition to those expressly described herein, the components, elements, actions, products, and methods described herein may be combined and rearranged, and still be considered within the scope of this invention.

[0025] According to variant 1, a method may include calculating a driver intention based on at least one of vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data; generating a desired vehicle speed based on the driver intention; transmitting the desired vehicle speed to a longitudinal kinematics motion controller; generating a desired longitudinal acceleration based on the desired vehicle speed; transmitting the desired longitudinal acceleration to a longitudinal feedforward compensation module; transmitting at least one braking command to the longitudinal feedforward compensation module; and generating at least one propulsion torque request based on the desired longitudinal acceleration and at least one braking command.

[0026] Variation 2 may include the method of claim 1, further comprising transmitting at least one propulsion torque request to a propulsion system within the vehicle.

[0027] Variation 3 may include the method as described in any one of Variations 1 to 2, the method further comprising manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering.

[0028] Variation 4 may include the method as described in any one of Variations 1 to 3, wherein manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering includes at least one of increasing or decreasing the acceleration of the vehicle via a propulsion system within the vehicle.

[0029] Variant 5 may include the method as described in any one of Variant claims 1 to 4, wherein generating at least one propulsion torque request based on a desired longitudinal acceleration and at least one braking command includes receiving desired longitudinal acceleration data; calculating a target force; receiving at least one braking command from a brake-steering system; calculating a target propulsion force based on the target force and the at least one braking command; transmitting the target propulsion force to a vehicle speed-dependent feedforward gain module; transmitting vehicle speed data to the vehicle speed-dependent feedforward gain module; and generating at least one propulsion torque request.

[0030] Variation 6 may include the method as described in any one of Variations 1 to 5, further comprising receiving vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data before determining the driver's intention based on at least one of vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data.

[0031] Variation 7 may include the method as described in any one of Variations 1 to 6, wherein determining the driver's intention includes associating vehicle speed data, accelerator pedal positioning data, and powertrain state data to determine whether the driver wishes to maintain, increase, or decrease at least one of the vehicle speed.

[0032] Variation 8 may include the method as described in any one of Variations 1 to 7, wherein transmitting at least one braking command to the longitudinal feedforward compensation module includes transmitting at least one braking command from the brake-steering system to the longitudinal feedforward compensation module.

[0033] According to variant 9, a method for use in a vehicle having multiple vehicle systems, the vehicle systems including a braking system configured to operate braking devices, a steering system configured to adjust the direction of road wheels, a propulsion system configured to transmit driving force to at least one road wheel, a brake-steering system, and a controller operatively communicating with the braking system, steering system, and propulsion system. The method may include implementing the brake-steering system within the vehicle, including transmitting a braking command to the braking system; generating vehicle speed data; generating accelerator pedal positioning data; generating at least one powertrain state data; transmitting at least one of the vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data to a driver intention function; determining a desired vehicle speed based on the vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data; transmitting the desired vehicle speed to a longitudinal kinematics motion controller; generating a desired longitudinal acceleration based on the desired vehicle speed via the longitudinal kinematics motion controller; transmitting the desired longitudinal acceleration to a longitudinal feedforward compensation module; and transmitting a braking command to the longitudinal feedforward compensation module, the longitudinal feedforward compensation module being configured and arranged to transmit a propulsion torque request to the propulsion system in the vehicle.

[0034] Variation 10 may include the method as described in any one of Variation 9, the method further comprising manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering.

[0035] Variation 11 may include the method as described in any one of Variations 9 to 10, wherein manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering includes at least one of increasing or decreasing the vehicle acceleration via a propulsion system within the vehicle.

[0036] Variant 12 may include the method as described in any one of Variant claims 9 to 11, the method further comprising, prior to transmitting a braking command to a longitudinal feedforward compensation module of a propulsion system configured and arranged to transmit a propulsion torque request to the vehicle, performing the following steps: receiving desired longitudinal acceleration data; calculating a target force; receiving at least one braking command from a brake-steering system; calculating a target propulsion force based on the target force and at least one braking command; transmitting the target propulsion force to a vehicle speed-dependent feedforward gain module; transmitting vehicle speed data to the vehicle speed-dependent feedforward gain module; and generating at least one propulsion torque request.

[0037] Variation 13 may include the method as described in any one of the Variations 9 to 12, wherein determining the driver's intention includes associating vehicle speed data, accelerator pedal positioning data, and powertrain state data to determine whether the driver wishes to maintain, increase, or decrease at least one of the vehicle speed.

[0038] According to variant 14, a system for managing longitudinal disturbances in a vehicle during braking-steering, the vehicle comprising multiple vehicle systems including: a braking system configured to operate braking devices, a steering system configured to adjust the direction of road wheels, a propulsion system configured to transmit driving force to at least one road wheel, a braking-steering system, and a controller operatively communicating with the braking system, steering system, and propulsion system, the system comprising the following steps: receiving vehicle speed data; receiving accelerator pedal positioning data; receiving at least one powertrain state data; calculating a driver intention based on at least one of the vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data; generating a desired vehicle speed based on the driver intention; transmitting the desired vehicle speed to a longitudinal kinematics motion controller; generating a desired longitudinal acceleration based on the desired vehicle speed; transmitting the desired longitudinal acceleration to a longitudinal feedforward compensation module; and transmitting at least one braking command from the braking-steering system to the longitudinal feedforward compensation module. The system may further include generating at least one propulsion torque request based on a desired longitudinal acceleration and the at least one braking command, including: receiving desired longitudinal acceleration data; calculating a target force; receiving at least one braking command from the brake-steering system; calculating a target propulsion force based on the target force and the at least one braking command; transmitting the target propulsion force to a vehicle speed-dependent feedforward gain module; transmitting vehicle speed data to the vehicle speed-dependent feedforward gain module; and generating at least one propulsion torque request. The system may further include transmitting the at least one propulsion torque request to a propulsion system within the vehicle; and manipulating the vehicle's propulsion to manage longitudinal acceleration disturbances and speed disturbances during brake-steering.

[0039] The above description of the alternative variations within the scope of this invention is merely illustrative in nature, and therefore, any variations or changes thereof should not be considered as departing from the spirit and scope of this invention.

Claims

1. A method for use in a vehicle having multiple vehicle systems, the multiple vehicle systems comprising: The method comprises: a braking system configured to operate braking devices; a steering system configured to adjust the direction of road wheels; a propulsion system configured to transmit driving force to at least one road wheel; a brake-steering system; and a controller operatively communicating with the braking system, the steering system, and the propulsion system. The driver's intention is calculated based on at least one of vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data. Generate the desired vehicle speed based on the driver's intent; The desired vehicle speed is transmitted to the longitudinal kinematics motion controller; The desired longitudinal acceleration is generated based on the desired vehicle speed; The desired longitudinal acceleration is transmitted to the longitudinal feedforward compensation module, wherein the longitudinal feedforward compensation module is configured and arranged to generate at least one propulsion torque request based on the desired longitudinal acceleration and the at least one braking command. Transmit the at least one braking command to the longitudinal feedforward compensation module; and At least one propulsion torque request is generated based on the desired longitudinal acceleration and the at least one braking command.

2. The method of claim 1, further comprising transmitting the at least one propulsion torque request to a propulsion system within the vehicle.

3. The method of claim 2, further comprising manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering.

4. The method of claim 3, wherein manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering includes at least one of increasing or decreasing the vehicle acceleration via a propulsion system within the vehicle.

5. The method of claim 1, wherein generating at least one propulsion torque request based on the desired longitudinal acceleration and the at least one braking command comprises: Receive the desired longitudinal acceleration data; Calculate the target force; Receive at least one braking command from the brake-steering system; Calculate the target propulsion force based on the target force and the at least one braking command; The target thrust is transmitted to the vehicle speed-related feedforward gain module; Transmit vehicle speed data to the vehicle speed-related feedforward gain module; and Generate at least one propulsion torque request.

6. The method of claim 1, further comprising: The system receives at least one of the following vehicle speed data, accelerator pedal positioning data, or powertrain state data before determining the driver's intention based on at least one of the following vehicle speed data, accelerator pedal positioning data, or powertrain state data: vehicle speed data, accelerator pedal positioning data, or powertrain state data.

7. The method of claim 6, wherein determining the driver's intention includes associating vehicle speed data, accelerator pedal positioning data, and powertrain state data to determine whether the driver wishes to maintain, increase, or decrease at least one of the vehicle speed.

8. The method of claim 1, wherein transmitting at least one braking command to the longitudinal feedforward compensation module comprises transmitting at least one braking command from the brake-steering system to the longitudinal feedforward compensation module.

9. A method for use in a vehicle having multiple vehicle systems, said vehicle systems comprising: A braking system configured to operate the braking device; A steering system configured to adjust the direction of the road wheels; A propulsion system configured to transmit driving force to at least one road wheel; A braking-steering system and a controller operatively communicating with the braking system, steering system, and propulsion system, the method comprising: Implementing a brake-steering system within the vehicle, including transmitting braking commands to the braking system; Generate vehicle speed data; Generate accelerator pedal positioning data; Generate state data for at least one dynamic system; Transmit at least one of the following: vehicle speed data, accelerator pedal positioning data, or at least one powertrain status data to the driver intent calculation module. Using the driver intention calculation module, the driver intention is determined based on at least one of vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data, in order to determine the desired vehicle speed. The desired vehicle speed is transmitted to the longitudinal kinematics motion controller; The desired longitudinal acceleration is generated based on the desired vehicle speed via a longitudinal kinematics motion controller; The desired longitudinal acceleration is transmitted to the longitudinal feedforward compensation module; and At least one braking command is transmitted to a longitudinal feedforward compensation module, which is configured and arranged to transmit a propulsion torque request to the propulsion system in the vehicle.

10. The method of claim 9, further comprising manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering.

11. The method of claim 10, wherein manipulating the propulsion of the vehicle to manage longitudinal disturbances during braking-steering includes increasing or decreasing the vehicle acceleration via a propulsion system within the vehicle.

12. The method of claim 9, further comprising, before transmitting the braking command to a longitudinal feedforward compensation module of the propulsion system configured and arranged to transmit a propulsion torque request to the vehicle: Receive the desired longitudinal acceleration data; Calculate the target force; Receive at least one braking command from the brake-steering system; Calculate the target propulsion force based on the target force and the at least one braking command; The target thrust is transmitted to the vehicle speed-related feedforward gain module; The vehicle speed data is transmitted to the vehicle speed-related feedforward gain module. and Generate at least one propulsion torque request.

13. The method of claim 9, wherein determining the driver's intention includes associating vehicle speed data, accelerator pedal positioning data, and powertrain state data to determine whether the driver wishes to maintain, increase, or decrease at least one of the vehicle speed.

14. A system for managing longitudinal disturbances in a vehicle during braking-steering, the vehicle comprising a plurality of vehicle systems, the plurality of vehicle systems including a braking system configured to operate braking devices, a steering system configured to adjust the direction of road wheels, a propulsion system configured to transmit driving force to at least one road wheel, a braking-steering system, and a controller operatively in communication with the braking system, the steering system, and the propulsion system, the system comprising: Receive vehicle speed data; Receive accelerator pedal positioning data; Receive at least one dynamic system state data; The driver's intention is calculated based on at least one of vehicle speed data, accelerator pedal positioning data, or at least one powertrain state data. Generate the desired vehicle speed based on the driver's intent; The desired vehicle speed is transmitted to the longitudinal kinematics motion controller; The desired longitudinal acceleration is generated based on the desired vehicle speed; The desired longitudinal acceleration is transmitted to the longitudinal feedforward compensation module; At least one braking command is transmitted from the brake-steering system to the longitudinal feedforward compensation module; and Generate at least one propulsion torque request based on the desired longitudinal acceleration and the at least one braking command, including: Receive the desired longitudinal acceleration data; Calculate the target force; Receive at least one braking command from the brake-steering system; Calculate the target propulsion force based on the target force and the at least one braking command; The target thrust is transmitted to the vehicle speed-dependent feedforward gain module; Transmit vehicle speed data to the vehicle speed-related feedforward gain module; and Generate at least one propulsion torque request; Transmit the at least one propulsion torque request to the propulsion system within the vehicle; and Manipulate the vehicle's propulsion to manage longitudinal acceleration and velocity disturbances during braking and steering.

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