Lane-Keeping Steering Force Limit Control for Smooth Driver Override
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Solution Overview
Problem
Existing lane keeping assist systems fail to appropriately adjust the force limit for steering operations, leading to unintended vehicle behavior and discomfort during transitions from automatic to manual control, especially when the driver's force exceeds a threshold or when the vehicle is on a curve.
Innovation Solution
A vehicle control device that acquires the positional relationship between a vehicle and a lane, performs in-lane travel control by adjusting the force limit, and dynamically adjusts the change rate of this limit based on the driver's steering operation state, including reducing the limit when excessive force is applied and returning it gradually when the force is mitigated, to ensure smooth transitions and reflect the driver's intentions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper limit of force exerted by the system is increased to improve lane keeping performance, then the vehicle stability is improved, but the driver's operating freedom deteriorates when the driver needs to make manual steering corrections
Solution Approach 1:
The upper limit of force is changed from a fixed value to a dynamically adjustable parameter. The control device switches between a first upper limit (stricter) and a second upper limit (looser) based on detected driver operating states, allowing the system to adapt between prioritizing lane keeping stability and driver operating freedom in different situations
Solution Approach 2:
The system changes the force limit parameter based on driver operation detection. When driver operation exceeding a threshold is detected, the system transitions from the first upper limit to the second upper limit, effectively changing the control parameter to resolve the contradiction between stability and operability
2Speed
If the upper limit of force is changed abruptly to respond to driver operation, then the system responds quickly to driver intentions, but unintended vehicle behavior and driver discomfort occur
Solution Approach 1:
The system prepares for potential abrupt changes by implementing gradual transition logic. When switching between upper limits, the force limit is adjusted incrementally over multiple control cycles rather than instantaneously, cushioning the transition to prevent sudden vehicle movements that would cause discomfort or unintended behavior
Solution Approach 2:
The system detects driver operation exceeding the threshold in advance and prepares for upper limit switching. By detecting the condition beforehand and implementing gradual adjustment, the system prevents abrupt changes while maintaining responsive behavior to driver intentions
3Device complexity
If the system maintains a fixed upper limit of force, then the control logic is simple, but the system cannot appropriately adapt to different driving situations and driver intentions
Solution Approach 1:
The system transitions from a static fixed upper limit to a dynamic adaptive upper limit that changes based on detected driver operating states. The control device monitors driver input and automatically adjusts between different upper limit values, providing adaptability to various driving situations while maintaining relatively simple control logic through state-based switching
Data Source
AI summary
Provided are a vehicle control device, a vehicle control method, and non-transitory storage medium. The vehicle control device includes: an acquisition part, acquiring a positional relationship between a vehicle and a lane; a control part, performing in-lane travel control that causes an actuator included in a steering device of the vehicle to output a force for causing the vehicle to travel in the lane within a range not exceeding an upper limit based on the positional relationship; and an upper limit adjustment part, adjusting the upper limit in a predetermined case, in which the upper limit adjustment part switches a change rate of the upper limit in response to a change of state of an operator that accepts a steering operation performed by an occupant of the vehicle.