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EP-4741258-A1 - ELECTROMECHANICAL STEERING SYSTEM, METHOD FOR OPERATING SAME, AND VEHICLE

EP4741258A1EP 4741258 A1EP4741258 A1EP 4741258A1EP-4741258-A1

Abstract

The invention relates to an electromechanical steering system (100) with an assistance device (102) for steering support, with a steering handle (104), with a steering angle sensor (106), with at least one steering axle (110), with an actuator (112), and with a steering control unit (114) which is configured to translate the detected steering angle into a wheel steering angle, wherein the actuator (112) is caused by means of the steering control unit (114) to adjust the wheel steering angle specified by the steering control unit (114), and wherein the steering control unit (114) is further configured to activate the assistance device (102) in the emergency or danger situation, which causes a decoupling of the wheel steering angle from the steering angle of the steering handle (104) by the actuator (112) changing or adjusting the wheel steering angle independently of the steering angle of the steering angle sensor (106). The steering control unit (110) is configured to monitor operation of the steering handle (104) during the activation of the assistance device (102), wherein the decoupling of the wheel steering angle from the steering angle of the steering handle (104) is released in several stages or continuously when a) a predefined torque or a predefined change in torque over time is detected by a torque sensor (108) assigned to the steering handle (104), or b) a predetermined change in steering angle over time is detected by the steering angle sensor (106). The invention also relates to a method for operating such a steering system (100) and a vehicle (200).

Inventors

  • PATZELT, MICHAEL
  • KAHNT, Andreas

Assignees

  • AUDI AG

Dates

Publication Date
20260513
Application Date
20250903

Claims (10)

  1. Electromechanical steering system (100) with an assistance device (102) for steering support, with a steering handle (104), with a steering angle sensor (106) assigned to the steering handle (104), wherein the steering angle sensor (106) is configured to detect a steering angle of the steering handle (104), with at least one steering axle (110), with one of the actuators (112) assigned to the steering axle (110), and with a steering control unit (114) which is configured to translate the detected steering angle into a wheel steering angle, wherein the actuator (112) is caused by means of the steering control unit (114) to set the wheel steering angle specified by the steering control unit (114), and wherein the steering control unit (114) is further configured to activate the assistance device (102) in the emergency or danger situation, wherein the activation of the assistance device (102) causes, at least partially, a decoupling of the wheel steering angle from the steering angle of the steering handle (104) by the actuator (112) changing or adjusting the wheel steering angle independently of the steering angle of the steering angle sensor (106), characterized by the fact that the steering control unit (110) is set up to monitor operation of the steering handle (104) during the activated assistance device (102), wherein the decoupling of the wheel steering angle from the steering angle of the steering handle (104) is resolved in several stages or continuously when a) a predefined torque or a predefined change in torque over time is detected by a torque sensor (108) assigned to the steering handle (104), or b) a predetermined change in steering angle over time is detected by the steering angle sensor (106).
  2. Electromechanical steering system (100) according to claim 1, characterized in that a steering column-free steer-by-wire steering system is provided.
  3. Electromechanical steering system (100) according to claim 1 or 2, characterized in that the steering control unit (114) is configured to monitor the operation of the steering handle (104) only after a predetermined time interval has elapsed following the activation of the assistance device (102).
  4. Electromechanical steering system (100) according to one of claims 1 to 3, characterized in that the steering control unit (114) is configured to decouple the wheel steering angle from the steering angle during a predefined period of time, so that during this period user intervention is also possible in parallel with the intervention of the assistance device (102).
  5. Method for operating an electromechanical steering system (100) according to any one of claims 1 to 4, comprising the steps: - Activating an assistance device (104) for steering support, for example when detecting an emergency or hazardous situation, wherein a wheel steering angle is decoupled from a steering angle of a steering handle (104) and, at least partially, the wheel steering angle is changed or set independently of the steering angle of a steering angle sensor (106) of the steering handle (108), - Monitor whether the steering handle (104) is operated while the assistance device (102) is activated, and - Releasing the decoupling of the wheel steering angle from the steering angle of the steering handle (104) in several stages or continuously, if a) a predefined torque or a predefined change in torque over time is detected by a torque sensor (108) assigned to one of the steering handles (104), or if b) a predetermined change in steering angle over time is detected by the steering angle sensor (106).
  6. Method according to claim 5, characterized in that the monitoring of the operation of the steering handle (104) only takes place after a predetermined time interval has elapsed following the activation of the assistance device (102).
  7. Method according to claim 5 or 6, characterized in that the decoupling of the wheel steering angle from the steering angle is released during a predefined period of time, so that during this period a user intervention can also take place in parallel with the intervention of the assistance device (102).
  8. Method according to one of claims 5 to 7, characterized in that the decoupling is linearly reduced during the predefined period.
  9. Method according to one of claims 5 to 7, characterized in that the decoupling is reduced exponentially during the predefined period.
  10. Vehicle (200) with an electromechanical steering system (100) according to one of claims 1 to 4.

Description

The invention relates to an electromechanical steering system, in particular an electromechanical steering system for two-track vehicles. Furthermore, the invention relates to a vehicle with such a steering system and a method for operating such an electromechanical steering system. Electromechanical steering systems, such as steer-by-wire systems, are primarily used to control two-track vehicles. In steer-by-wire systems, there is no mechanical connection between the steering handle and the steering gear. Instead, the force and travel of both the steering handle and the steered vehicle wheels are controlled electronically. Modern driver assistance systems in vehicles can support the driver in various driving maneuvers or situations. For example, these systems can automatically keep the vehicle in its lane, regulate and maintain the distance to the vehicle ahead, or provide assistance during emergency braking. An intervention by such a system therefore occurs in emergency and hazardous situations. During steering intervention, driver assistance systems retain full control authority and, in case of misinterpretation, can steer the vehicle before the driver has fully assessed the situation. Such autonomous intervention by the assistance system can unsettle the driver, especially when using steer-by-wire systems. The user lacks immediate feedback on the driving situation during the assistance intervention, as the absence of a mechanical connection to the wheel(s) means that no torque is transmitted to the steering handle. Furthermore, the driver receives no feedback on the trajectory recommended by the assistance system. In the DE102023200693A1 This document describes an assistance system for autonomously moving a vehicle into an optimized dynamic driving state, and a vehicle equipped with a system for controlling the vehicle. Specifically, it proposes a vehicle control system that, upon request, interacts with the driver and adapts the vehicle control to the driver's wishes and/or abilities. Essentially, this document focuses on implementing a database that records multiple drivers and executes interventions based on this data. Driver behavior is analyzed by an AI and stored in a database. Driver feedback is generated based on deviations from the target behavior and is also recorded. While there is a risk that the database could learn incorrect driver behavior, the fact that multiple drivers and driving modes are stored in this database then serves as the data basis for assistance interventions is a significant concern. In the DE102021205110A1 A device and a method for controlling a vehicle during aquaplaning, as well as a vehicle itself, are described. The device is designed to respond to a detection signal representing an aquaplaning condition at the front axle of the vehicle, decoupled from a directional signal representing a desired change in the vehicle's direction of travel, by providing a front axle signal to effect a front steering angle adapted to the aquaplaning condition. In the DE102016217772A1 A device, an operating procedure, and an electronic control unit for controlling a vehicle capable of at least partial automated driving are described. The assistance system described therein can either decouple the steering angle position of the steering wheel from the wheel angle position or (completely) couple them. It is therefore the object of the present invention to provide an electromechanical steering system, a method for operating such a system and a vehicle with such a system, which contribute to an improved switching from an intervention of the assistance device to a user intervention. This problem is solved by an electromechanical steering system with the features of claim 1, by a method with the features of claim 5, and by a vehicle with the features of claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the dependent claims. The electromechanical steering system according to the invention comprises an assistance device for steering support, particularly in emergency or hazardous situations. However, it is also possible for the assistance device of the steering system according to the invention to be used to support comfort functions or autonomous/semi-autonomous driving. Particularly in semi-autonomous driving, a faster handover between steering by the driver and steering by the assistance device is possible, and it is also possible to keep the steering wheel straight. The driver can regain control by steering intervention as soon as they apply steering torque or exceed a steering torque threshold. The assistance device of the steering system according to the invention can also be used in an autonomous parking function, where the steering wheel is straight and the driver must be able to intervene in an emergency. For steering input by the user, a steering handle is provided, which may be, for example, a steering wheel. However, other types