Adaptive Cruise Control Using a Virtual Target for Smooth Merging

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Solution Overview

Problem

State-of-the-art adaptive cruise control systems are unreliable, leading to abrupt acceleration or deceleration due to late speed corrections when dealing with multiple vehicles, especially when vehicles change lanes or merge, causing discomfort and safety issues.

Innovation Solution

A method and system that calculates a virtual barycentric target based on multiple surrounding vehicles, anticipating their trajectories to smooth ACC control by determining a virtual barycentric target's position, velocity, and acceleration, using sensors to identify and predict the kinematic attributes of surrounding vehicles, and adjusting the ego vehicle's speed and distance accordingly without modifying the ACC control loop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional adaptive cruise control systems regulate distance based on a single target vehicle, then the control system is simple to implement, but the system becomes unreliable when vehicles change lanes or merge, causing abrupt acceleration or deceleration

Engineering Contradiction:
Improvereliability of ACC systemVSAvoidcomplexity of control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the control approach by separating target identification from distance regulation. It identifies multiple target vehicles independently, calculates individual distances to each target, then selects the minimum distance for ACC regulation. This segmentation allows the system to consider multiple targets without requiring a completely new control architecture, thus improving reliability while maintaining manageable complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary identification and tracking of multiple potential target vehicles before the actual distance regulation occurs. By continuously monitoring and pre-calculating distances to multiple vehicles, the system is prepared for sudden lane changes or merges, allowing smooth transitions rather than abrupt corrections. This preliminary action prevents the reliability issues that occur when targets are identified too late.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the ACC system reacts late to target vehicle lane changes or merges, then the control response time is reduced, but this causes abrupt acceleration or deceleration leading to discomfort and safety issues

Engineering Contradiction:
Improvesmoothness of vehicle controlVSAvoidresponse time for speed correction
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent continuously identifies and tracks multiple potential target vehicles in advance, maintaining ready-calculated distance measurements for each. When a lane change or merge occurs, the system already has the distance data needed for immediate smooth adjustment, eliminating the need for late reactive corrections. This preliminary tracking ensures both timely response and smooth control transitions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements continuous feedback by monitoring the positions and distances of multiple target vehicles in real-time. The system constantly updates distance measurements to each tracked vehicle and uses this feedback to maintain appropriate spacing. This continuous feedback loop ensures the vehicle responds smoothly to changing traffic conditions without abrupt accelerations or decelerations.

Inventive Principle:
Principle #23Feedback

3Reliability

If the system only tracks one target vehicle at a time, then the computational load is low, but the system cannot anticipate vehicle insertions or lane changes effectively

Engineering Contradiction:
Improveanticipation capabilityVSAvoidcomputational energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the target tracking process by independently identifying multiple vehicles and calculating distances to each one separately. Rather than using a single complex multi-target algorithm, it divides the task into multiple simple single-target calculations, which are then combined by selecting the minimum distance. This segmentation reduces computational complexity while enabling effective anticipation of lane changes and vehicle insertions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs calculations for more target vehicles than strictly necessary for single-lane operation, tracking multiple vehicles that may potentially change lanes or merge. This excessive action of monitoring additional targets provides the anticipation capability needed for reliable ACC control in dynamic traffic conditions, while the selective minimum-distance approach keeps computational energy consumption manageable.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4157689B1Driver assistance method with virtual target for adaptive cruise control
Publication Date: 2025.10.29 NISSAN MOTOR CO LTD
  • EP4157689B1 patent drawingFigure 1~2
  • EP4157689B1 patent drawingFigure 3~4
  • EP4157689B1 patent drawingFigure 5~6

AI summary

The invention relates to a driver assistance method for a so-called ego vehicle (EGO) travelling in a traffic lane, comprising: a first step of identifying traffic surrounding the ego vehicle in the same traffic lane as the ego vehicle and in adjacent parallel lanes travelling in the same direction; a second step of determining a virtual barycentric target (G), comprising the calculation of a position of the virtual barycentric target, a speed of the virtual barycentric target and an acceleration of the virtual barycentric target; a third step of calculating a longitudinal speed setpoint of the ego vehicle (EGO), an acceleration setpoint and a torque setpoint, the longitudinal speed setpoint being a function of the position of the virtual barycentric target (G), the speed of the virtual barycentric target (G), and the acceleration of the virtual barycentric target (G).