Convoy Speed Control for Curve-Limited Following Vehicles

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Solution Overview

Problem

Conventional adaptive cruise control systems fail to account for lateral acceleration in following vehicles on curves, leading to issues such as deteriorated ride quality, slipping, or freight collapsing.

Innovation Solution

A control method and system that allows following vehicles to communicate their maximum allowable velocities to a lead vehicle, which adjusts its speed to ensure that all vehicles in the convoy maintain velocities that do not exceed these limits, thereby preventing excessive lateral acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the lead vehicle accelerates to improve productivity, then the convoy moves faster, but the following vehicle on a curve experiences excessively large lateral acceleration causing deteriorated ride quality, slipping, or freight collapsing

Engineering Contradiction:
Improveconvoy speedVSAvoidlateral acceleration
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The following vehicle calculates its maximum allowable velocity based on curve geometry and turning performance before entering the curve, and transmits this information to the lead vehicle in advance. The lead vehicle then adjusts its acceleration profile proactively to ensure the following vehicle does not experience excessive lateral acceleration, preventing ride quality deterioration, slipping, or freight collapse before these issues occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The following vehicle continuously monitors its own velocity, the lead vehicle's velocity, and the curvature of the road ahead. Based on this feedback, it dynamically calculates the maximum allowable velocity that maintains lateral acceleration within acceptable limits and communicates this back to the lead vehicle, enabling real-time adjustment of the convoy's acceleration profile.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If conventional adaptive cruise control limits the velocity of the lead vehicle to allow the following vehicle to follow, then lateral acceleration is reduced, but the convoy's overall speed and productivity decrease

Engineering Contradiction:
Improvelateral accelerationVSAvoidconvoy speed
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

Instead of using a fixed velocity limit for the lead vehicle, the system dynamically calculates the maximum allowable velocity based on real-time conditions including curve curvature, the following vehicle's turning performance, and current speed. This dynamic adjustment allows the convoy to maintain higher speeds on straight sections while automatically reducing speed only when necessary on curves, optimizing both comfort and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the velocity parameter of the lead vehicle based on the calculated maximum allowable velocity, which varies with road geometry and vehicle conditions. By continuously adjusting this parameter rather than applying a static limit, the system maintains productivity while preventing excessive lateral acceleration.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4095004B1Vehicle control method, vehicle control system and convoy of vehicles
Publication Date: 2025.08.06 ASTEMO LTD
  • EP4095004B1 patent drawingFigure 1
  • EP4095004B1 patent drawingFigure 2
  • EP4095004B1 patent drawingFigure 3

AI summary

A lead vehicle (1) in an adaptive cruise control system that non-mechanically connects a following vehicle (2) to the lead vehicle (1) sequentially and that causes the following vehicle (2) to follow its immediately preceding vehicle calculates vehicle velocity limit (V1max) for limiting a velocity of the lead vehicle (1) based on maximum allowable vehicle velocity (V2max) of the following vehicle (2), maximum allowable vehicle velocity (V2max) satisfying a turning performance of the following vehicle (2), and controls a brake apparatus and a drive apparatus such that the velocity of the lead vehicle (1) will not exceed vehicle velocity limit (V1max).