Steering Assist Apparatus Non-Holding Detection Logic
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Solution Overview
Problem
Existing steering assist systems, such as lane tracing assist (LTA) and lane changing assist (LCA), face challenges in ensuring the driver maintains control of the steering wheel, leading to potential lane deviations and misinterpretation of control status, particularly during LCA where a nonzero yaw angle is normal.
Innovation Solution
The system incorporates lane recognition, steering assist control, non-holding detection, and duration time measurement to warn the driver and adjust control modes, ensuring the driver holds the wheel by setting specific conditions for LTA and LCA operations, including continued LCA execution until completion regardless of non-holding duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LTA is stopped when the non-holding duration time becomes more than or equal to a predetermined time, then the driver is urged to hold the steering wheel, but the LCA cannot be properly executed when the non-holding duration time becomes more than or equal to the predetermined time
Solution Approach 1:
The control system dynamically adjusts its behavior based on the type of steering assist control being executed. During LTA, the system stops control when non-holding duration exceeds the threshold to urge driver engagement. During LCA, the system continues control even when the threshold is exceeded, recognizing that temporary driver release is normal during lane changes. This dynamic adaptation resolves the contradiction by applying different rules to different operational contexts.
Solution Approach 2:
The system changes the effective threshold parameter based on the control mode. For LTA, the threshold is applied strictly to ensure driver engagement. For LCA, the threshold is effectively suspended or adjusted, allowing the control to continue despite extended non-holding periods. This parameter change enables the system to maintain reliability for LTA while ensuring ease of operation for LCA.
2Ease of operation
If the driver is allowed to release the steering wheel during LCA, then the lane changing can proceed automatically, but the driver may misrecognize the control status due to nonzero yaw angle
Solution Approach 1:
The system provides continuous feedback to the driver through the operation state notification device, clearly indicating when LCA is active and when it has completed. This feedback mechanism compensates for the driver's inability to visually monitor the steering wheel position during automatic operation, preventing misrecognition of control status. The notification device serves as an information bridge between the system and driver.
Solution Approach 2:
The system prepares the driver for automatic operation by providing advance notification that LCA is about to execute or is currently executing. This preliminary action ensures the driver understands the control status before and during the automatic lane changing process, preventing confusion that would arise from unexpected automatic steering movements.
3Reliability
If the non-holding duration threshold is set low, then driver engagement is encouraged, but normal lane changing operations are interrupted
Solution Approach 1:
The system dynamically adapts the threshold application based on operational context. During LTA, a strict threshold ensures driver monitoring. During LCA, the system suspends threshold enforcement to allow complete lane changing operations without interruption. This dynamic approach resolves the contradiction between driver monitoring reliability and lane changing efficiency.
Solution Approach 2:
Different threshold enforcement policies are applied to different operational modes. LTA receives strict threshold enforcement to ensure driver engagement, while LCA receives relaxed or suspended enforcement to ensure operational efficiency. This local quality differentiation allows the system to optimize for the appropriate criterion in each operational context.
Data Source
AI summary
A steering assist apparatus comprises a steering assist control means for performing a lane tracing assist control (LTA) and a lane changing assist control (LCA) and a non-holding determination means for determining whether or not a first non-holding condition that a non-holding duration time is more than or equal to a first time is satisfied and whether or not a second non-holding condition that the non-holding duration time is more than or equal to a second time shorter than the first time is satisfied. The steering assist control means raises a warning when the second non-holding condition becomes satisfied and stops the LTA when the first non-holding condition becomes satisfied while performing the LTA, and raises a waring when the second non-holding condition becomes satisfied whereas continues the LCA until a completion condition of the LCA becomes satisfied regardless of the non-holding while performing the LCA.