Steer-By-Wire Feedback Actuation for Passive Steering Feel
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Solution Overview
Problem
Steer-by-wire steering systems lack sufficient steering resistance and restoring torque in passive operating modes, failing to replicate the familiar steering feel and support functions provided by conventional steering systems, such as bracing against the steering wheel during vehicle entry and exit.
Innovation Solution
Implement a simulation function in the computing unit to adjust the steering resistance and restoring torque of the feedback actuator, simulating the behavior of bore and self-aligning torques through modules for spring, friction, damping, and inertia, enhancing the steering feel and support functions in passive operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the feedback actuator is switched off or kept inactive in passive operating mode to save energy, then energy consumption is reduced, but steering resistance and restoring torque become insufficient for driver support
Solution Approach 1:
The feedback actuator operates dynamically with different control strategies based on the operating mode. In passive operating mode, it activates simulation functions that dynamically adjust steering resistance and restoring torque to match conventional steering behavior, while in normal driving mode it operates with standard control algorithms. This dynamic adaptation resolves the contradiction by providing adequate steering support when needed while allowing energy-saving operation when the vehicle is in passive mode.
Solution Approach 2:
The system changes the control parameters of the feedback actuator based on the operating mode. In passive operating mode, parameters such as steering resistance coefficients and restoring torque characteristics are adjusted to simulate conventional steering system behavior, including bore torque and self-aligning torque effects. This parameter adaptation enables the actuator to provide appropriate steering resistance without requiring continuous high-energy operation.
2Ease of operation
If the feedback actuator is activated to provide steering resistance, then steering support function is improved, but the steering feel does not match the familiar behavior of conventional steering systems
Solution Approach 1:
The simulation function creates a virtual model of conventional steering system behavior by copying the characteristic torque-angle relationships, including bore torque and self-aligning torque effects. The feedback actuator is controlled to reproduce these copied characteristics, providing steering resistance and restoring torque that closely match the familiar feel of conventional steering systems, thereby resolving the adaptability issue while maintaining steering support functionality.
3Ease of operation
If a mechanical connection between steering control element and steering angle adjuster is maintained to provide steering resistance, then steering support is improved, but the steer-by-wire system loses its advantage of electrical-only signal transmission
Solution Approach 1:
The patent replaces the mechanical connection with an electrical control system. The feedback actuator, controlled by a simulation function in the computing unit, generates steering resistance and restoring torque electronically to substitute for the mechanical torque transmission that would exist in conventional steering systems. This substitution maintains the steer-by-wire advantage of electrical-only signal transmission while providing the necessary steering support through active control rather than passive mechanical connection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The simulation function improves the steering feel and support functions in passive operating modes, providing a familiar and realistic steering experience by replicating the behavior of conventional steering systems, enhancing driver comfort and safety.
Implementation Method 1
the feedback actuator is provided to detect signals, forces, and/or torques from the steering control element, in particular directly, and/or to transmit them to the steering control element, in particular directly
Implementation Method 2
simulating the behavior of bore and self-aligning torques through modules for spring, friction, damping, and inertia
Implementation Method 3
simulating the behavior of bore and self-aligning torques through modules for spring, friction, damping, and inertia
Implementation Method 4
simulating the behavior of bore and self-aligning torques through modules for spring, friction, damping, and inertia
Implementation Method 5
simulating the behavior of bore and self-aligning torques through modules for spring, friction, damping, and inertia
Data Source
AI summary
The disclosure relates to a method for influencing a movement of a steering control element of a steer-by-wire steering system in a vehicle, in particular a motor vehicle, in which method the steer-by-wire steering system comprises at least one feedback actuator for producing a steering resistance and/or a restoring torque acting on the steering control element. In at least one operating state in which the vehicle is stationary and is in a passive operating mode which is different from a normal driving operating mode, as a response to an external force acting on the steering control element, the steering resistance and/or the restoring torque of the feedback actuator are/is set and/or changed by means of a simulation function in such a way that a behavior of the steering control element which correlates with a bore torque and/or self-aligning torque is simulated.