Lane Centering Assist Torque Threshold Dynamics
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Solution Overview
Problem
Current Lane Centering Assist systems struggle to determine driver activity accurately when the vehicle is in a curve, leading to potential failure in activating the system due to torque threshold conflicts with driver control takeover thresholds.
Innovation Solution
A method that determines driver activity by calculating the derivative of the torque applied to the steering wheel and checks if this derivative remains below a threshold for a predetermined duration, ensuring stable vehicle trajectory maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the torque threshold for LCA activation is increased to allow activation in curves, then the system can be activated in curved conditions, but it conflicts with the driver control takeover threshold and may prevent LCA activation
Solution Approach 1:
The patent applies dynamics by making the torque threshold adaptive rather than fixed. The threshold dynamically adjusts based on vehicle operating conditions (speed, steering angle, yaw rate) to differentiate between driver intent to activate LCA and driver intent to take control. This resolves the contradiction by allowing high torque thresholds in curves for LCA activation while maintaining low thresholds for driver takeover when needed.
Solution Approach 2:
The patent changes the parameter of torque threshold from a static value to a dynamic value that varies with vehicle speed, steering angle, and yaw rate. This allows the system to accommodate different driving scenarios: higher thresholds enable LCA activation in curves, while lower thresholds ensure driver takeover responsiveness when the driver intends to take control.
2Reliability
If the torque threshold is set low to ensure driver control takeover responsiveness, then driver takeover is reliable, but LCA cannot be activated when the vehicle is in a curve
Solution Approach 1:
The system dynamically adjusts the torque threshold based on real-time vehicle conditions. When the vehicle is in a curve with appropriate speed and steering angle, the threshold is raised to allow LCA activation. When the driver intends to take control (detected through yaw rate and steering angle rate of change), the threshold is lowered to ensure responsive takeover.
Solution Approach 2:
The system uses feedback from multiple sensors (steering angle sensor, yaw rate sensor, speed sensor) to continuously monitor driving conditions and adjust the torque threshold accordingly. This feedback mechanism enables the system to distinguish between driver actions that indicate LCA activation intent versus driver actions that indicate takeover intent, resolving the contradiction between activation capability and takeover reliability.
3Device complexity
If a fixed torque threshold is used for LCA activation, then the system is simple to implement, but it cannot accurately determine driver activity in curved conditions
Solution Approach 1:
The patent transforms the simple fixed threshold approach into a multi-parameter dynamic threshold system that considers vehicle speed, steering angle, and yaw rate. This increases measurement precision for driver activity determination in curved conditions while maintaining reasonable system complexity through the use of standard vehicle sensors and a structured threshold adjustment algorithm.
Data Source
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AI summary
A method for controlling a motor vehicle provided with a line centring system and a means for determining the torque applied by the driver to the steering wheel. The method comprises the following steps: determining the force couple applied by the driver to the steering wheel, determining the absolute value of the time derivative of the determined force couple, determining if the absolute value of the derivative of the force couple is lower than a predetermined force couple threshold, determining the time period that has elapsed during which the absolute value of the time derivative of the determined force couple has been lower than the predetermined force couple threshold, determining if the time period that has elapsed is at least equal to a predetermined time period, If this is the case, transmitting an authorisation signal concerning the activity of the driver to the line centring system.