CACC Speed Profile Control for Fuel-Efficient Vehicle Following
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Solution Overview
Problem
Existing CACC systems face challenges in maintaining fuel efficiency due to frequent acceleration and deceleration when adjusting to the speed of a target vehicle, leading to inefficient fuel consumption.
Innovation Solution
A CACC system that utilizes V2X communications and radar to select a target vehicle based on specific criteria, set a new target speed profile, and control the vehicle's speed to optimize fuel efficiency by minimizing unnecessary decelerations and maintaining a safe distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the CACC system performs deceleration driving to maintain a predetermined distance to the target vehicle, then the safety and collision prevention are improved, but the fuel efficiency deteriorates due to frequent acceleration and deceleration control
Solution Approach 1:
The system pre-calculates a cost value for maintaining current speed and a cost value for decelerating to follow the target vehicle's speed before making a control decision. By evaluating these pre-calculated costs, the system determines whether deceleration is necessary, thereby avoiding unnecessary acceleration-deceleration cycles and improving fuel efficiency while maintaining collision prevention
Solution Approach 2:
The system dynamically changes the control parameter from always maintaining a fixed predetermined distance to adaptively adjusting the following distance based on cost evaluation. When the cost of maintaining current speed is lower, the system allows larger following distances; when deceleration cost is lower, it reduces distance. This parameter adaptation resolves the contradiction by optimizing both safety and fuel efficiency
2Adaptability or versatility
If the CACC system frequently adjusts acceleration and deceleration to match the target vehicle speed, then the adaptability to target vehicle is improved, but the fuel efficiency deteriorates due to stiff control
Solution Approach 1:
Instead of continuously and fully adjusting speed to match the target vehicle, the system performs partial action by selectively applying deceleration only when the cost evaluation indicates it is necessary. The system compares costs and applies deceleration control only in situations where it optimizes overall fuel efficiency, rather than rigidly following the target vehicle in all conditions
Solution Approach 2:
The system transitions from static control (fixed predetermined following distance) to dynamic control (adaptive following distance based on real-time cost evaluation). The control parameters dynamically adjust based on the calculated costs of maintaining current speed versus decelerating, enabling the system to adapt to target vehicle speed changes while minimizing unnecessary energy consumption
Data Source
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AI summary
Disclosed herein is a control apparatus and method for improving fuel efficiency in a CACC system (300), which can improve fuel efficiency through control of a vehicle speed so that a vehicle travels using an optimized cost in consideration of a target vehicle speed, current vehicle speed, minimum driving speed set in the vehicle, and a deceleration distance if the vehicle that uses the CACC system (300) senses a forward vehicle and enters into a CACC active mode (610, 621, 622, 623). The control method for improving fuel efficiency in a CACC system (300) includes setting a target speed profile based on a target speed of the subject vehicle and an expected driving path, determining whether a target vehicle to be followed by the subject vehicle exists, and controlling the driving speed of the subject vehicle according to the set target speed profile depending on whether or not the target vehicle exists.