Adaptive Cruise Braking Range Adjustment via Lateral Offset and Road Curvature
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Solution Overview
Problem
Conventional adaptive cruise-with-braking (ACB) systems fail to consider lateral offset of a target vehicle and road curvature when determining braking reactions, leading to inadequate safety and increased false positive alerts.
Innovation Solution
An ACB system that adjusts the braking reaction distance based on lateral offset and road curvature, using sensors and a controller to set an initial braking reaction distance and define a following distance limit shape, limiting deceleration requests unless the target vehicle breaches these limits, and reducing the braking reaction distance when the road curvature is less than a predetermined value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ACB systems use a single longitudinal threshold or reference azimuth angle to determine braking reactions, then the system complexity is reduced, but the safety and accuracy of braking decisions deteriorates due to failure to consider lateral offset and road curvature
Solution Approach 1:
The patent transitions from conventional single-dimensional (longitudinal) or two-dimensional (azimuth angle) threshold systems to a three-dimensional following distance limit shape that incorporates longitudinal distance, lateral offset, and road curvature. This dimensional expansion enables comprehensive safety assessment by considering spatial position in multiple directions simultaneously, resolving the contradiction between reliability improvement and complexity increase through systematic integration of additional spatial parameters.
Solution Approach 2:
The patent implements dynamic adjustment of the following distance limit shape based on real-time road curvature detection and lateral offset measurement. The braking reaction distance is no longer fixed but adapts dynamically to changing road conditions and vehicle positions, allowing the system to maintain high reliability across varying driving scenarios while managing complexity through adaptive rather than static parameter settings.
2Speed
If conventional ACB systems activate brakes based on single longitudinal threshold events, then the response time is reduced, but false positive alerts increase leading to driver desensitization
Solution Approach 1:
The patent incorporates feedback mechanisms by continuously monitoring both longitudinal distance and lateral offset of the target vehicle relative to the host vehicle's path. The system uses this feedback to dynamically determine whether the target vehicle is actually in the braking range, adjusting the following distance limit shape based on real-time positional data. This multi-parameter feedback approach maintains rapid response capability while significantly reducing false positives by verifying target vehicle position across multiple spatial dimensions before triggering braking alerts.
Data Source
AI summary
When employing an adaptive cruise-with-braking (ACB) system to control host vehicle braking reaction distance, a following distance limit shape (FDLS) is defined using a lateral offset function, and a lateral offset of a forward vehicle is detected and analyzed. If the vehicle has a lateral offset greater than a lateral offset defined by the lateral offset function, deceleration requests from an engine controller are limited to requesting deceleration by an engine retarder and/or a dethrottling module. If the lateral offset of the forward vehicle is less than a lateral offset defined by the lateral offset function, foundation brakes may be requested. In other embodiments, road curvature is determined, and a braking reaction distance is reduced when the radius of curvature is smaller than a threshold curvature, in order to reduce false positive braking reactions triggered by, e.g., a forward vehicle on an exit ramp while the host vehicle remains on the highway.