Vehicle Steering Control Fallback on Curved Roads
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Solution Overview
Problem
Existing vehicles with advanced steering control systems face challenges in safely shifting to manual steering when a failure occurs, particularly on curved roads, as immediate cessation of the Lane Keeping Assist (LKA) function can lead to unsafe navigation.
Innovation Solution
A moving body equipped with a steering system and a control device that executes first and second steering controls based on its state, allowing safe transition to manual steering by maintaining the steering angle or torque when a failure occurs, using a threshold-based approach to enable driver intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LKA function is immediately stopped when a failure occurs, then the system responds quickly to the failure, but the vehicle cannot move safely along the road, especially on arc-shaped roads
Solution Approach 1:
The patent applies dynamics by making the steering control mode switchable between automatic (LKA) and manual based on failure detection and driver input. The system dynamically transitions from first steering control to second steering control when failures occur, and allows flexible switching between automatic and manual steering modes based on operation amount thresholds, enabling the control system to adapt to different operational states and failure conditions
Solution Approach 2:
The patent implements beforehand cushioning by preparing a backup steering control mode (second steering control) that maintains the steering angle before failure occurs. This pre-prepared fallback mechanism ensures continuous safe operation on curved roads even when the primary LKA function fails, cushioning against the potential harm of complete steering control loss
2Reliability
If the steering control is switched to manual control immediately when a failure occurs, then the driver takes over control, but the vehicle may not maintain the intended traveling direction, especially on curved roads
Solution Approach 1:
The patent applies preliminary action by maintaining the steering angle at the value present before failure occurs during second steering control. This preserves the vehicle's intended traveling direction on curved roads without requiring immediate driver intervention, allowing the vehicle to continue following the planned path while awaiting driver input
Solution Approach 2:
The system dynamically adjusts the threshold for driver intervention based on the current control mode. During first steering control, a first threshold value is used, while during second steering control, a second threshold value (larger than the first) is used, allowing flexible transition timing between automatic and manual control based on failure state and driver input magnitude
3Adaptability or versatility
If a single threshold value is used for switching from automatic to manual steering control, then the control logic is simple, but it cannot provide appropriate response for different failure states and driving conditions
Solution Approach 1:
The patent implements dynamics by making the operation amount threshold variable depending on the steering control mode. The control device switches between a first threshold value during first steering control and a second threshold value (larger than the first) during second steering control, allowing the system to adapt its response characteristics to different failure states and driving conditions
Data Source
AI summary
A moving body includes: a steering system configured to change steering of the moving body; and a steering control device configured to control the steering of the moving body by controlling the steering system. The steering control device selectively executes first steering control for controlling the steering of the moving body and second steering control for restricting the steering of the moving body, executes the second steering control when a failure related to execution of the first steering control occurs, ends the first steering control when an operation amount of an operation member exceeds a first threshold value in the state where the first steering control is being executed, and ends the second steering control when an operation amount of the operation member exceeds a second threshold value larger than the first threshold value in a state where the second steering control is being executed.