Motor Grader Blade Positioning via GNSS and IMU Sensors

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Solution Overview

Problem

Existing 3D grade control systems for construction machines, such as motor graders, face limitations including reduced blade placement range, increased theft risk, and potential damage due to mast interactions, necessitating improved positioning and control methods.

Innovation Solution

Integrating inertial measurement units (IMUs) and Global Navigation Satellite System (GNSS) receivers with the grader to establish blade positions within a world space, eliminating the need for mast-based systems and enhancing positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mast-based 3D grade control systems are used, then blade positioning control is achieved, but blade placement range is reduced and risk of damage increases

Engineering Contradiction:
Improveblade positioning controlVSAvoidblade placement range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent removes the physical mast structure from the blade positioning system. Instead of using masts mounted on the blade to detect position, the system uses GNSS receivers mounted on the machine body to determine blade position through spatial transformation calculations. This extraction eliminates the physical constraints and damage risks associated with mast-based systems while maintaining positioning control capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical mast-based detection system with an electronic positioning system using GNSS receivers and computational geometry. The system calculates blade position in world space by transforming coordinates from machine space using measured machine pose data, substituting mechanical contact-based measurement with satellite-based positioning and mathematical transformation.

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

2Measurement precision

If mast-based 3D grade control systems are used, then blade positioning control is achieved, but theft risk and damage potential increase

Engineering Contradiction:
Improveblade positioning controlVSAvoidtheft risk and damage potential
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the vulnerable mast components from the system and relocates the positioning sensors (GNSS receivers) to the machine body. This removes the exposed, easily stolen, and damage-prone elements from the blade area while maintaining the core positioning functionality through alternative measurement and calculation methods.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If traditional positioning methods are used, then system simplicity is maintained, but positioning accuracy in world space is reduced

Engineering Contradiction:
Improvesystem simplicityVSAvoidpositioning accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces spatial transformation calculations as an intermediary process between machine-based measurements and world space positioning. The system uses measured machine pose (position and orientation) as an intermediary to transform blade position coordinates from machine space to world space, enabling accurate global positioning without requiring complex additional hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4722646A2Motor grader 3D grade control
Publication Date: 2026.04.08 CATERPILLAR TRIMBLE CONTROL TECHNOLOGIES LLC
  • EP4722646A2 patent drawingFigure 1
  • EP4722646A2 patent drawingFigure 2A
  • EP4722646A2 patent drawingFigure 2B

AI summary

Systems and methods for providing grade control on a motor grader without the use of masts attached to the blade. Embodiments include a body angle sensor configured to detect movement of a construction machine's body wherein the body is coupled to an intermediate linkage via a first articulating connection, a front positioning sensor configured to detect a geospatial position of the construction machine's body within a world space, an intermediate linkage angle sensor configured to detect movement of the intermediate linkage, and a working implement angle sensor configured to detect movement of a working implement wherein the working implement is coupled to the intermediate linkage via a second articulating connection. Two positions on the working implement may be calculated first within a machine space and subsequently within the world space. Movement of at least one articulating connection may be caused based on the working implement positions within the world space.