Grass Marking Vehicle Using Local Radio Localization

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Solution Overview

Problem

Existing methods for reproducing images on grassed areas, such as stadiums and golf courses, face challenges with GPS interference from surrounding structures, image distortion due to terrain and camera angles, and lack of automation for precise and repeatable pattern creation across different locations.

Innovation Solution

A method using a vehicle with marking means that defines an orthonormal local coordinate system, adjusts the pattern's height-to-width ratio, partitions the area into elementary cells, and uses real-time localization to control the marking process, allowing for distortion compensation and autonomous operation without relying on GPS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS system is used to direct the vehicle and control marking equipment, then positioning and control capability is improved, but the system becomes infeasible for grassy areas surrounded by stands where satellite links are obstructed

Engineering Contradiction:
Improvepositioning precisionVSAvoidadaptability to different environments
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary localization system that uses a network of fixed reference stations positioned around the grassy area. These reference stations communicate with the vehicle via radio frequency to provide position data, serving as a mediator between the vehicle and the marking control system. This intermediary approach bypasses the need for satellite GPS signals, enabling operation in environments surrounded by stands or structures that block satellite links.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the satellite-based electromagnetic positioning system (GPS) with a ground-based radio frequency communication system. The vehicle exchanges position information with reference stations through wireless communication, substituting the mechanical/satellite infrastructure with a localized electronic communication network that functions independently of satellite availability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If pattern is marked on grassy area without distortion compensation, then marking process is simple, but the image appears distorted to observers inside the stadium or television cameras

Engineering Contradiction:
Improvemarking process simplicityVSAvoidimage accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing a transformation matrix that compensates for perspective distortion before the marking operation begins. The system determines the optimal camera position and observation angle in advance, then uses these parameters to generate a distorted version of the desired pattern that, when marked on the ground, will appear correct from the target observation point. This preliminary preparation eliminates the need for complex real-time calculations during marking.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the geometric parameters of the pattern through mathematical transformation. By applying a perspective transformation matrix that accounts for the camera position, observation angle, and field geometry, the system modifies the pattern's shape, scale, and orientation parameters. This parameter transformation ensures that the marked pattern compensates for perspective distortion and appears accurate from the intended viewing position.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If manual marking process is used, then equipment complexity is low, but the application of designs cannot be rapid, repeatable, and precise across different stadiums

Engineering Contradiction:
Improvesystem complexityVSAvoidmarking speed and repeatability
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements self-service by enabling the marking system to autonomously determine its position, calculate the appropriate pattern transformation, and execute marking without human intervention. The vehicle independently communicates with reference stations to obtain position data, automatically applies the pre-calculated transformation matrix, and controls the marking equipment based on its real-time location. This automation eliminates the need for manual positioning and pattern adjustment, enabling rapid and repeatable application across different stadiums.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates feedback through continuous position monitoring and verification. The vehicle constantly exchanges position information with reference stations, and the system verifies that the marked pattern aligns with the intended design by comparing real-time position data against the pre-calculated transformation parameters. This feedback mechanism ensures precision and enables automatic correction of any deviations during the marking process.

Inventive Principle:
Principle #23Feedback

4Device complexity

If pattern is marked without considering altimetric shape of the surface, then marking process is simpler, but significant image distortion occurs especially in golf fairways

Engineering Contradiction:
Improvemarking process complexityVSAvoidimage accuracy on uneven terrain
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent extends parameter changes to include three-dimensional surface geometry. The transformation matrix is enhanced to incorporate altimetric data, accounting for variations in elevation across the marking area. By integrating surface profile parameters into the mathematical transformation, the system adjusts the pattern's vertical and horizontal dimensions to compensate for terrain undulations, ensuring accurate appearance from the observation point even on uneven surfaces like golf fairways.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3755138B1Method for reproducing a pattern to be marked on a grassed area
Publication Date: 2023.03.08 NATURAL GRASS
  • EP3755138B1 patent drawingFigure 1~2
  • EP3755138B1 patent drawingFigure 3~4

AI summary

According to said method, from a local coordinate system (O; x, y, z), the grassed area (T) is digitised and a marking area (Q) is divided into elementary cells to form a matrix (M).; the pattern to be marked is broken down into a mosaic of pixels associated with the elementary cells of the matrix (M). Subsequently, for each elementary cell of the matrix, tasks to be performed by the marking means are determined according to a value of the pixel associated with the elementary cell, to mark the pattern to be marked on the marking area; and the movement of the vehicle (V) over the grassed area to cover all the elementary cells is controlled, as well as the marking means for carrying out the tasks to be performed in each elementary cell. Application in the field of advertising on the grassed area.