Adaptive Cruise Control Using Target Deceleration Feedback
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Solution Overview
Problem
Autonomous vehicles equipped with adaptive cruise control systems experience delays in responding to sudden decelerations of preceding vehicles, leading to insufficient inter-vehicle distance maintenance, especially at low speeds, causing psychological discomfort and potential emergency braking.
Innovation Solution
A method that activates adaptive speed regulation by calculating and adjusting the ego-vehicle's acceleration based on target vehicle information, including distance and acceleration, to ensure a predetermined inter-vehicular time is maintained, with an alert signal triggering substitution of set acceleration with target acceleration when necessary, and wireless communication for situational awareness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive cruise control uses predetermined set acceleration calculated from set inter-vehicular time, then the system maintains stable speed regulation, but the system responds slowly to sudden target vehicle deceleration
Solution Approach 1:
The system performs preliminary action by using the target vehicle's measured acceleration (which is already available from radar/LIDAR) to adjust the ego-vehicle's acceleration command in real-time, rather than waiting for the inter-vehicular time calculation cycle to complete. This preliminary use of target acceleration data allows the system to respond immediately to target vehicle deceleration while maintaining the predetermined set acceleration as a fallback for normal conditions.
2Stability of the object's composition
If the system maintains a fixed inter-vehicular time, then the distance calculation is simple and stable, but the system cannot adapt to sudden changes in target vehicle behavior
Solution Approach 1:
The system applies dynamics by making the acceleration command dynamic and adaptable. While the inter-vehicular time remains a stable predetermined parameter, the actual acceleration applied to the ego-vehicle becomes dynamic by incorporating real-time target vehicle acceleration measurements. This allows the system to adapt to sudden target deceleration events while maintaining the structural stability of the cruise control algorithm.
3Device complexity
If the system calculates acceleration based on predetermined parameters, then the control logic is simple and fast, but the system generates abrupt deceleration causing psychological discomfort
Solution Approach 1:
The system uses target vehicle acceleration as an intermediary parameter to smooth the transition to emergency braking. Instead of directly applying full emergency braking when a target is detected, the system first applies the target's acceleration value (which is typically less severe), creating a gradual deceleration profile that reduces psychological discomfort while still maintaining safety.
4Measurement precision
If the system uses radar or LIDAR to detect target vehicle, then the system can measure distance and speed, but the measurement delay causes the system to approach the target vehicle too abruptly
Solution Approach 1:
The system implements feedback by continuously monitoring the target vehicle's acceleration and using this information to adjust the ego-vehicle's acceleration command in real-time. The feedback loop uses the measured target acceleration as a direct input to modify the cruise control output, compensating for the inherent delays in radar/LIDAR measurement and processing cycles.
Data Source
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AI summary
The invention relates to a method and a device for regulating the speed of an autonomous vehicle, referred to as ego vehicle, comprising an adaptive cruise control, said method comprising the steps of activating (201) said adaptive cruise control, receiving (202) information relating to said target vehicle, referred to as target information, receiving (203) information relating to said ego vehicle, referred to as ego vehicle information, determining (204) an inter-vehicle time, determining (205) an alert signal from said target information and said ego vehicle information, determining conditions (206) for substituting (207) a target acceleration for a setpoint acceleration of said cruise control.