Vehicle Test Load Control Using Dynamic Tire Diameter

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Solution Overview

Problem

Existing vehicle test apparatuses using a fixed tire diameter cannot accurately reproduce the actual running conditions of a vehicle due to tire deformation during different running states, leading to inaccuracies in simulation.

Innovation Solution

A specimen test apparatus that calculates tire diameters corresponding to the running state of the vehicle using tire diameter data and controls loading devices to apply running resistance based on these calculated diameters, allowing for accurate simulation of actual vehicle runs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed tire diameter is used in the test apparatus, then the device complexity is reduced and operation is simplified, but the measurement precision and reliability of reproducing actual vehicle running conditions deteriorates

Engineering Contradiction:
Improveaccuracy of reproducing actual vehicle runVSAvoidcomplexity of tire diameter calculation and control system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic adjustment of the tire diameter parameter during the test based on the measured running state. The control device calculates the actual tire diameter corresponding to the current running speed and acceleration, then adjusts the loading resistance accordingly. This transforms the fixed parameter system into a dynamic one that adapts to changing test conditions, resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the tire diameter parameter from a fixed value to a variable that depends on the running state (speed and acceleration). By storing multiple tire diameter values corresponding to different running states and selecting the appropriate value during testing, the system achieves accurate reproduction of actual vehicle conditions without requiring complex real-time calculations, thus balancing precision and complexity.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a fixed tire diameter is used, then the ease of operation is improved, but the adaptability to different running states (speed, acceleration) deteriorates

Engineering Contradiction:
Improveadaptability to different running statesVSAvoidsimplicity of test setup and control
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent performs preliminary preparation by storing multiple tire diameter values corresponding to different running states (speeds and accelerations) in advance. During the actual test, the control device simply retrieves the appropriate pre-calculated tire diameter value based on the current running state, rather than performing complex real-time calculations. This preliminary action approach maintains ease of operation while achieving high adaptability to different running conditions.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3705867B2Specimen test apparatus
Publication Date: 2026.03.18 HORIBA LTD
  • EP3705867B2 patent drawingFigure 1
  • EP3705867B2 patent drawingFigure 2
  • EP3705867B2 patent drawingFigure 3

AI summary

The present invention is one that reproduces behavior close to an actual run of a vehicle in a test using a loading device, and is a specimen test apparatus that tests a specimen that is a vehicle or a part of a vehicle. The vehicle test apparatus includes: a loading device that is connected to a rotating shaft of the specimen and gives running resistance to the rotating shaft; a storage part that stores tire diameter data indicating the relationship between a running state of the specimen and a tire diameter; and a control part that, from the tire diameter data, calculates a tire diameter corresponding to a running state of the specimen, and controls the loading device with use of running resistance obtained from the calculated tire diameter.