Vehicle Travel Control Using LTR-Based Rollover Risk Deceleration

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing travel control methods for vehicles fail to adequately address the risk of rollover when excessive disturbances, such as wind, lead to steep steering angles, increasing the likelihood of vehicle rollover.

Innovation Solution

A travel control device and method that calculates a rollover risk level based on the lateral load transfer ratio (LTR) of the vehicle, and when this risk exceeds a threshold, it adjusts the target speed by deceleration to prevent rollover, using a risk level calculator and deceleration calculator to control the vehicle's driving system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If corrected steering angle amount for disturbance is taken into account, then vehicle can travel along target route despite wind influence, but steep steering angle operation increases rollover risk

Engineering Contradiction:

Improveroute tracking accuracyVSAvoidrollover risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system calculates the rollover risk level in advance based on lateral load transfer ratio before executing steering operations. When risk exceeds threshold, the control unit preemptively reduces target speed to prevent rollover, rather than reacting after the hazard occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically changes the target speed parameter based on calculated rollover risk level. When risk is high, target speed is reduced; when risk is low, normal speed is maintained. This parameter adjustment resolves the contradiction by adapting vehicle operation to real-time stability conditions

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If target speed is reduced to prevent rollover, then vehicle stability improves, but travel efficiency and productivity decrease

Engineering Contradiction:

Improverollover riskVSAvoidtravel efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts target speed based on real-time rollover risk assessment rather than maintaining a fixed low speed. The control unit continuously monitors lateral load transfer ratio and modifies speed commands accordingly, enabling high speed when safe and reduced speed only when necessary

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by continuously calculating rollover risk level from vehicle state data and using this information to adjust target speed. This closed-loop control ensures speed reduction occurs only when risk thresholds are exceeded, maintaining productivity when conditions permit

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12115987B2Travel control device, vehicle, travel control method, and program

Publication Date: 2024.10.15 MITSUBISHI HEAVY IND LTD

AI summary

A travel control device includes: a risk level calculation unit configured to acquire a speed in a traveling direction of a vehicle, a speed of the vehicle in a horizontal direction perpendicular to the traveling direction, and an azimuth angular velocity of the vehicle and calculate a rollover risk level based on a lateral load transfer ratio (LTR) of the vehicle; a deceleration calculation unit configured to calculate deceleration indicating an extent to which to lower the speed in the traveling direction when an absolute value of the rollover risk level exceeds a threshold value; and a control unit configured to control a driving system of the vehicle using a value obtained by lowering a target speed of the vehicle on the basis of the deceleration as a new target speed.