Three-Point Linkage Geometry Calculation via Sensor Data

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Solution Overview

Problem

Operators of agricultural tractors face difficulties in correctly adjusting the three-point power lift due to the lack of operator-independent methods for assessing the setting state, particularly for inexperienced users.

Innovation Solution

A method that calculates characteristic geometric and manipulated variables of the three-point power lift using sensors to determine the attachment position of lifting struts, the length of lifting struts, and the attachment position of upper links, allowing for operator-independent detection and assessment of the setting state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual adjustment of the three-point linkage is performed by the operator, then the linkage can be adjusted to accommodate different implement types and operating conditions, but the accuracy of the setting depends on the operator's practical experience and is difficult for inexperienced operators to assess correctly

Engineering Contradiction:
Improveadjustment range for different implement typesVSAvoidaccuracy of setting assessment
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces manual operator assessment with an automated sensor-based measurement system. Position sensors detect the actual positions of the lift arm and lower link, while acceleration sensors measure angular positions. This electronic measurement system substitutes the operator's subjective judgment, providing objective and precise measurement of the linkage geometry regardless of operator experience level.

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

Solution Approach 2:

The patent introduces an electronic control unit as an intermediary between the physical three-point linkage and the operator. The control unit receives data from multiple sensors, calculates geometric parameters, determines mounting positions, and communicates results to the operator. This intermediary process automates the complex geometric assessment that previously required operator expertise.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If multiple sensors and calculations are implemented to enable operator-independent detection of the setting state, then measurement precision and automation are improved, but the device complexity increases

Engineering Contradiction:
Improveoperator-independent detection capabilityVSAvoidnumber of sensors and calculation steps
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent employs sensors that serve multiple functions within the three-point linkage system. Position sensors and acceleration sensors are used not only for detecting mounting positions but also for determining linkage geometry, calculating lengths of lifting struts and top links, and assessing overall setting state. This multi-functionality reduces the need for separate dedicated sensors for each measurement task.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the existing structural elements of the three-point linkage (the lift arm, lower link, and their inherent geometric relationships) as part of the measurement system. By calculating geometric parameters based on sensor data from components already present in the system, the patent avoids adding extensive external measurement apparatus.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3311639B1Method for calculating characteristic geometry and/or the actuating variables of a three point hydraulic lift
Publication Date: 2019.07.31 DEERE & CO
  • EP3311639B1 patent drawingFigure 1
  • EP3311639B1 patent drawingFigure 2
  • EP3311639B1 patent drawingFigure 3~4

AI summary

Method for calculating characteristic geometric and/or control variables of a three-point linkage of an agricultural tractor, in which the first geometric and/or control variable is the mounting position of a lift arm adjustable by means of a lift arm in one of several mounting bores formed in a lower link pivotable by means of the lift arm, by first bringing the lower link into a horizontal angular position α = 0 and recording a corresponding position Px, Pz of the lift arm as well as a corresponding angular position γ of the lift arm relative to the vertical, wherein to determine the mounting position of the lift arm on the lower link, it is determined for which of the mounting bores a geometric constraint of the form UixUiz=PxPz−asinγcosγ is satisfied, in which Uix, Uiz denote the positional coordinates of the i-th mounting bore and a is a variable representing the length of the lift arm.