Electromechanical Steering Torque Adaptation for Natural Oversteering
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Solution Overview
Problem
Existing electromechanical steering systems for vehicles often result in unnatural and incomprehensible steering torque for drivers during oversteering, leading to reduced driving comfort and acceptance of driver assistance functions, as they do not adjust torque levels and directions effectively to the driving situation.
Innovation Solution
A system that includes a control unit with interfaces for receiving driver torque information and adjustment information based on the driving state or situation, allowing for the generation of modified steering control information that adjusts the steering movement to feel more natural and intuitive to the driver, by modifying the steering control information based on driver torque and adjustment information, such as oversteering stiffness, to reduce counter-torque and enhance cooperative driving behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the driver assistance system controls steering by eliminating driver torque as a disturbance, then control quality during lane guidance is improved, but the steering torque becomes unnatural and incomprehensible to the driver during oversteering
Solution Approach 1:
The control unit dynamically adapts the steering torque characteristics based on the driving situation. When the driver oversteers, the system transitions from eliminating all driver torque to providing differentiated torque support, making the steering feel natural while maintaining control quality. This is achieved by evaluating driving situations and adjusting the torque response accordingly.
Solution Approach 2:
The system changes the parameters of steering torque (level, course, direction) based on the evaluated driving situation. Instead of applying a fixed counter-torque, the control unit adjusts these parameters dynamically to provide comprehensible and natural steering feedback to the driver during oversteering maneuvers.
2Speed
If the overall disturbance transfer function has high dynamics to quickly eliminate driver torque, then the counter-torque responds faster, but the driver torque increases continuously up to the safety barrier level
Solution Approach 1:
The control unit dynamically adjusts the parameters of the disturbance transfer function based on the driving situation. When the driver oversteers, the system modifies the torque response characteristics to prevent continuous torque increase, thereby maintaining fast response while limiting excessive counter-torque.
Solution Approach 2:
The system dynamically adapts the control dynamics to balance response speed and torque magnitude. By evaluating the driving situation, the control unit adjusts the dynamics of the disturbance transfer function to provide appropriate torque levels that are responsive yet comfortable for the driver.
3Measurement precision
If the driver assistance system specifies a nominal steering angle, then lane guidance control is achieved, but the driver experiences additional steering torque during emergency maneuvers
Solution Approach 1:
The control unit adjusts the steering torque parameters based on the evaluated driving situation. During emergency maneuvers, the system modifies the nominal steering angle specification to reduce or eliminate additional counter-torque, allowing the driver to execute emergency steering without opposition from the driver assistance system.
4Reliability
If the motor torque of the actuator is limited to ensure oversteerability, then safety barrier is maintained, but the steering torque becomes unnatural during normal driving
Solution Approach 1:
The control unit dynamically changes the steering torque parameters based on the driving situation. During normal driving, the system adjusts torque levels to provide natural steering feedback, while maintaining the safety barrier through adaptive control that ensures oversteerability is preserved when needed.
Data Source
AI summary
A system for actuating an electromechanical steering system of a vehicle includes a driver assistance system, which generates a first item of steering control information, and a control unit having a first interface which receives driver torque information, and at least one second interface which receives at least one item of adjustment information which is dependent on the driving state and/or the driving situation. The control unit provides a second item of steering control information which is dependent on the driver torque information and the at least one item of adjustment information, and the system provides a modified item of steering control information to the steering system of the vehicle based on the first and the second item of steering control information, a steering movement being executed on the electromechanical steering system based on the modified item of steering control information.