Lane Keeping Assist Speed-Adaptive Torque Control
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Solution Overview
Problem
Existing lane keeping assist systems face challenges in maintaining effective lane keeping performance at low vehicle speeds due to the difficulty in generating proper lateral force, as the relation between steering torque and lateral force changes significantly between high and low speed travel.
Innovation Solution
A lane keeping assist apparatus that includes target steering angle calculation, feedforward and feedback control variables, vehicle speed detection, and adjustment mechanisms to adjust feedforward control torque based on vehicle speed, allowing for the generation of appropriate steering torque across the entire vehicle speed range by prioritizing feedback control at low speeds and combining with feedforward control at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vehicle speed range for lane keeping assist control is expanded to low speed, then the versatility of the system is improved, but the ability to generate proper lateral force deteriorates
Solution Approach 1:
The patent applies dynamics by making the control system adaptive to different vehicle speed conditions. The ECU dynamically switches between high-speed control processing and low-speed control processing based on detected vehicle speed, allowing the system to maintain optimal performance across the entire speed range by adjusting control parameters and strategies according to current operating conditions
Solution Approach 2:
The patent implements parameter changes by modifying control parameters based on vehicle speed. During low-speed travel, the system changes control parameters to account for reduced lateral force generation capability, while during high-speed travel, it uses parameters optimized for higher lateral force conditions, thereby resolving the contradiction between expanded speed range and lateral force generation
2Device complexity
If the same target steering torque calculation method is used for both high speed and low speed travel, then the device complexity is reduced, but the lane keeping assist performance deteriorates at low speed
Solution Approach 1:
The patent applies dynamics by implementing a dynamic control strategy that adapts to vehicle speed conditions. The ECU automatically selects between different control processing modes (high-speed or low-speed) based on real-time speed detection, ensuring optimal lane keeping performance across all speed ranges without requiring complex manual configuration
Solution Approach 2:
The patent implements feedback by continuously monitoring vehicle speed and using this information to adjust the control strategy. The ECU receives feedback about current operating conditions and modifies the target steering torque calculation accordingly, switching between high-speed and low-speed control processing to maintain reliable lane keeping assist performance
Data Source
AI summary
A lane keeping assist apparatus has a vehicle speed responsive adjustment section which receives a target steering angle and a vehicle speed, sets a vehicle speed adjustment coefficient on the basis of the vehicle speed, multiplies an FF target steering torque by the vehicle speed adjustment coefficient, and outputs the resultant value as an adjusted FF target steering torque. The vehicle speed adjustment coefficient is set to 0 when the vehicle speed is lower than a first set vehicle speed and to 1 when the vehicle speed is higher than a second set vehicle speed. An adding section adds the adjusted FF target steering torque and an FB target steering torque together and outputs the resultant value as a final target steering torque.