Steering Assist System Driver Intervention Handling
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Solution Overview
Problem
Existing Lane Keeping Support Systems (LKS) cause unpleasant steering feelings for drivers due to varying counterforces when the driver intervenes, as the system's control forces can be disruptive and lead to sudden changes in steering responsibility.
Innovation Solution
The system adjusts its parameters during driver intervention to provide a comfortable steering experience by interrupting the feedback branch, transitioning through phases with specific control adjustments, including setting PID components to 0 and using non-linear control to mimic independent steering, and gradually returning to normal operation based on quality measures and control deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the LKS system maintains active control forces to keep the vehicle on target trajectory, then trajectory keeping precision is improved, but driver steering comfort deteriorates due to varying counterforces during driver intervention
Solution Approach 1:
The control system dynamically adapts its behavior based on driver intervention detection. When driver steering torque exceeds a threshold, the system transitions from active trajectory correction to a more passive mode that allows driver freedom while maintaining system readiness. This dynamic switching resolves the contradiction by adjusting control aggressiveness according to operational context.
Solution Approach 2:
The system changes control parameters (particularly the proportional gain Kp in the PID controller) based on detected driver intervention. During normal operation, higher gains provide precise trajectory keeping. During driver intervention, gains are reduced or frozen to provide comfortable steering feel. This parameter adaptation allows the system to optimize both precision and comfort at different times.
2Ease of operation
If the LKS system deactivates steering support when driver intervention is detected, then driver steering freedom is improved, but steering stability deteriorates due to sudden loss of control support
Solution Approach 1:
The system prepares for potential driver intervention by having pre-defined control modes ready. When intervention is detected, the system smoothly transitions to a cushioned mode where control forces are gradually reduced or frozen rather than abruptly removed. This prevents sudden instability while still providing driver freedom during intervention.
Solution Approach 2:
The system periodically monitors driver steering torque to detect intervention. This continuous periodic detection allows the system to respond timely to driver actions while maintaining normal operation during non-intervention periods. The periodic nature ensures both driver freedom during intervention and stability during normal operation are achieved.
3Manufacturing precision
If the LKS system increases manipulated variable (steering torque) to correct trajectory deviation, then trajectory accuracy is improved, but driver steering comfort worsens due to increased countersteering forces
Solution Approach 1:
The system uses feedback from driver steering torque detection to modulate its control output. When driver torque indicates intervention, the system reduces or freezes its own torque output to avoid conflicting with driver actions. This feedback mechanism allows the system to maintain accuracy when appropriate while prioritizing comfort during driver intervention.
Solution Approach 2:
The control system dynamically adjusts its torque output based on real-time detection of driver intervention. During normal operation, the system applies sufficient torque for accurate trajectory keeping. During driver intervention, the system dynamically reduces torque application to provide comfortable steering feel. This dynamic adaptation resolves the contradiction between accuracy and comfort.
Data Source
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AI summary
The method involves performing a normal controlled operation when no driver action is present. The normal operation is switched when a driver carries out a steering action by changing a control parameter in an activated condition of control and/or feedback. The controlled operation is taken place during the driver action in a phase, where an integral- and/or differential control part is set to zero in the phase. Switching from a linear controlled operation to a non-linear controlled operation is taken place. An independent claim is also included for a device for operating a lane keeping support system.