Vehicle Steering Handover Using Blended Path Control
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Solution Overview
Problem
Automated driving systems face challenges in smoothly transitioning steering control from automated to operator control, especially when the driver is fully engaged and navigating a path free of obstacles, as existing systems struggle to reject undesirable steering inputs and ensure a seamless handover.
Innovation Solution
The method involves determining a projected vehicle path using sensor data, blending steering commands to create a blended vehicle path that satisfies specific criteria, and gradually relinquishing control to the operator, with the system selectively rejecting or accepting steering inputs based on predetermined conditions, including a confidence interval analysis to assess operator engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the automated driving system completely relinquishes steering control to the operator, then the operator has full control freedom, but the vehicle may deviate from the safe projected path or collide with obstacles
Solution Approach 1:
The patent introduces a blended steering command as an intermediary between the automated system's projected path and the operator's steering input. The controller combines the automated steering command with the operator's steering input using a blending factor, creating a intermediate control signal that maintains safety while allowing operator engagement. This resolves the contradiction by providing a mediator that prevents complete relinquishment of control while still enabling operator participation.
Solution Approach 2:
The blending factor is dynamically adjusted based on the operator's engagement level and the safety of the blended path. When the operator is fully engaged and the blended path satisfies safety criteria, the blending factor increases to allow more operator control. When safety criteria are not met, the blending factor decreases to maintain automated control. This dynamic adjustment resolves the contradiction by adapting control freedom to real-time safety conditions.
2Reliability
If the automated driving system maintains full steering control, then the vehicle path safety is ensured, but the operator engagement level remains insufficient for smooth handover
Solution Approach 1:
The system continuously monitors the operator's steering input and compares it with the projected path to determine the operator's engagement level. This feedback mechanism allows the system to assess whether the operator is actively controlling the vehicle and adjust the blending factor accordingly. When the operator demonstrates sufficient engagement with steering inputs that satisfy safety criteria, the system gradually increases control freedom, enabling smooth handover while maintaining safety.
3Speed
If the system rapidly transfers steering control to the operator, then the handover speed is increased, but the transition becomes abrupt and unsafe
Solution Approach 1:
The system performs preliminary assessment of the operator's engagement level and the safety of the blended path before increasing control transfer. The blending factor is gradually increased over multiple control cycles as the operator demonstrates competent steering inputs, rather than making abrupt changes. This preliminary action ensures that the handover process is both fast enough to be efficient and smooth enough to maintain safety and stability.
Data Source
AI summary
A method of controlling a vehicle includes determining a first projected path of the vehicle, receiving sensor data corresponding to a steering input, determining a first blended vehicle path resulting from a first blended steering command based on the first projected path and the sensor data, and determining when the first blended vehicle path satisfies a first criteria. When the controller determines that the first blended vehicle path satisfies the first criteria, the controller relinquishes control of the vehicle to an operator and when the controller determines that the first blended vehicle path does not satisfy the first criteria, the controller generates a second blended vehicle path resulting from a second blended steering command based on the first projected path and the sensor data.