Grass surrogate

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Solution Overview

Problem

Existing vehicle testing environments lack effective surrogates that accurately mimic roadside grass to test road departure mitigation systems, particularly for autonomous vehicles, without causing damage to the vehicle or surrogate.

Innovation Solution

A grass surrogate system that replicates the visual, infrared, and radar characteristics of natural grass, allowing vehicles to safely test road departure systems without damaging the surrogate or vehicle, using synthetic grass blades with high-gloss acrylic paint and pigments, and specific orientation to match real-world conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If natural grass is used for vehicle testing, then the visual appearance is accurate, but the grass gets damaged during repeated use

Engineering Contradiction:
Improvetesting accuracyVSAvoidsurrogate lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent creates a synthetic copy of natural grass that replicates its visual, infrared, and radar characteristics. The artificial grass surrogate uses painted synthetic blades to mimic the optical properties of real grass while being made from durable materials that resist damage during vehicle testing, thus solving the contradiction between testing accuracy and surrogate lifespan.

Inventive Principle:
Principle #26Copying

2Reliability

If real grass is used to test road departure systems, then the testing environment is realistic, but the vehicle may cause damage to the grass and surrounding objects

Engineering Contradiction:
Improvetesting realismVSAvoidvehicle damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The synthetic grass surrogate replicates the visual, infrared, and radar characteristics of natural grass, providing a realistic testing environment for road departure systems. Meanwhile, the controlled test environment with the surrogate eliminates harmful factors by preventing vehicle collisions with real grass and surrounding roadside objects, thus resolving the contradiction between testing realism and damage risk.

Inventive Principle:
Principle #26Copying

3Temperature

If artificial turf with heat reflecting materials is used, then heat reflection is improved, but the visual appearance may be altered

Engineering Contradiction:
Improveheat reflectionVSAvoidvisual appearance
Core Design Contradiction:
TemperatureVSShape

Solution Approach 1:

The patent applies different properties to different parts of the grass surrogate. The synthetic blades are painted with specific coatings that provide heat reflection properties, while the overall structure and color are designed to maintain natural grass appearance. This local differentiation of properties allows the surrogate to reflect heat effectively while preserving visual realism.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The grass surrogate system provides accurate sensor data mimicry, enabling safe and effective testing of road departure systems, reducing maintenance costs and ensuring compliance with safety standards, while avoiding damage during repeated use.

Implementation Method 1

the blade body is at least partially covered by a coating that includes a mixture of paint and pigments. The paint is high-gloss acrylic paint. The pigments are high reflectance pigments.

Methodology Applied
Scientific EffectInfrared reflectance: Reflection

Implementation Method 2

A plurality of grass blades are operatively connected to the base. Each grass blade includes a blade body... configured to exhibit substantially the same characteristics as a natural grass relative to one or more vehicle sensors (e.g., a camera sensor, a LIDAR sensor, or a radar sensor).

Methodology Applied
Scientific EffectRadar cross section: Scattering

Data Source

PatentEP3914773B1Grass surrogate
Publication Date: 2025.12.17 TOYOTA JIDOSHA KK
  • EP3914773B1 patent drawingFigure 1~3
  • EP3914773B1 patent drawingFigure 4
  • EP3914773B1 patent drawingFigure 5~6

AI summary

Surrogates for roadside objects can be used for vehicle testing. A grass surrogate can be configured to exhibit substantially the same characteristics as natural grass when sensed by one or more vehicle sensors (e.g., cameras, radar sensors, and/or LIDAR sensors). Such surrogates can be used to test autonomous vehicles, one or more vehicle sensors, a vehicle sensor system, and/or one or more vehicle systems (e.g., a road departure mitigation system). The grass surrogate can help a vehicle to identify road boundaries, particularly in portions of a road that do not include lane markings. The grass surrogate can be configured to withstand being driven over by a test vehicle without being damaged and/or without damaging the test vehicle. In some arrangements, the grass surrogate can include artificial grass that is coated with a mixture of high gloss acrylic paint and high reflectance pigments.