Steering System Cooperative Mode Transition Logic
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Solution Overview
Problem
When switching from autonomous steering mode to manual steering mode, existing systems may abruptly switch without ensuring the driver is prepared, leading to inappropriate steering control.
Innovation Solution
A steering system that includes an electric motor, a detector, and a controller, which switches between autonomous, manual, and cooperative steering modes. The controller switches to a cooperative mode before the actual switch to manual mode, allowing for weighted manual steering command values based on driver arousal levels and automatically stops if the driver is not ready, ensuring smooth transition and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the steering mode is immediately switched from autonomous steering mode to manual steering mode when a situation to switch is predicted, then the system responds quickly to predicted situations, but the driver may not be sufficiently ready for manual driving resulting in inappropriate steering control
Solution Approach 1:
The system performs preliminary action by switching to cooperative steering mode before the driver needs to take full manual control. When a situation requiring manual intervention is predicted, the system proactively transitions to a state where both autonomous and manual commands are integrated, giving the driver advance notice and preparation time while maintaining safe autonomous operation in the background.
Solution Approach 2:
The steering control is segmented into distinct modes: autonomous steering mode, cooperative steering mode, and manual steering mode. This segmentation allows gradual transition from full autonomy to full manual control through the intermediate cooperative mode, where both autonomous and manual commands are weighted and combined, enabling smooth handover that respects driver readiness.
2Device complexity
If the steering mode is immediately switched to manual steering mode, then the system maintains simple control logic, but the transition may be abrupt and inappropriate when the driver is not ready
Solution Approach 1:
The control system is divided into distinct operational modes (autonomous, cooperative, manual) with clear transition criteria. The cooperative steering mode serves as an intermediate state where both autonomous and manual commands are processed simultaneously with weighted integration, creating a natural bridge between full autonomy and full manual control that simplifies the overall control logic while improving transition smoothness.
Solution Approach 2:
The system dynamically adjusts the weighting between autonomous and manual steering commands based on the current operational mode and driver input. In cooperative steering mode, the weighting factors can be adjusted to smoothly blend autonomous and manual control, making the transition adaptive and context-dependent rather than abrupt or fixed.
3Reliability
If the system waits for driver readiness before switching to manual mode, then steering control reliability is improved, but the response time to predicted situations is delayed
Solution Approach 1:
The system takes preliminary action by transitioning to cooperative steering mode in advance when a situation requiring manual intervention is predicted. This preliminary transition prepares the driver and the control system simultaneously, maintaining high reliability by ensuring the driver is ready before full manual control is needed, while minimizing time loss by having the cooperative mode already active when the situation occurs.
Solution Approach 2:
The cooperative steering mode maintains continuous useful action by keeping the autonomous steering system active while incorporating manual input. Rather than completely disengaging autonomous control during the transition period, the system continuously processes both autonomous and manual commands with appropriate weighting, ensuring uninterrupted and reliable steering control throughout the transition.
Data Source
AI summary
A steering system includes an electric motor, a detector, and a controller of a vehicle. The controller is configured to control the electric motor by switching an autonomous steering mode, a manual steering mode, and a cooperative steering mode. The controller is configured to control the electric motor in the cooperative steering mode unconditionally or when a predetermined condition is satisfied in a case where a situation to switch a steering mode to the manual steering mode during control in the autonomous steering mode is predicted and a manual steering request is transmitted at a time point that is prior, by a first predetermined time, to occurrence of the situation, or is transmitted when the vehicle arrives at a point that is located a first predetermined distance before a point where the situation is to occur.