Tree Feller Lean Control Reduces Torsional Load

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Solution Overview

Problem

Tree felling machines face high torsional loads due to the high center of gravity of cut trees, leading to potential structural failure and the need for heavier, more robust attachments and counterweights, which increase weight and environmental impact.

Innovation Solution

A controlled lean system for tree feller-bunchers that uses sensors to measure the orientation of the boom and felling head, estimating the necessary lean to reduce torsional load during rotation, allowing for the use of lighter attachments and reducing the risk of structural failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a more robust and heavy attachment is used to withstand high torsional load, then structural reliability is improved, but the total weight of the tree feller-buncher increases

Engineering Contradiction:

Improvestructural reliabilityVSAvoidtotal weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The system performs preliminary action by leaning the cut tree in the direction of rotation before the boom rotation occurs. This preparatory positioning of the tree's center of gravity reduces the torsional load that will be experienced during rotation, allowing the use of lighter attachments while maintaining structural reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the spatial parameter of the tree's position by actively controlling its lean angle and direction. By adjusting the tree's orientation parameter (leaning it in the rotation direction), the system modifies the load distribution and reduces torsional stress on the attachment, enabling weight reduction.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If additional counterweight is added to balance the tree feller-buncher, then stability is improved, but the total weight and ground pressure increase

Engineering Contradiction:

Improvemachine stabilityVSAvoidground pressure

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The system applies preliminary action by positioning the tree's center of gravity in advance through controlled leaning. This pre-positioning compensates for the high center of gravity issue without requiring additional counterweights, thereby maintaining stability while avoiding increased ground pressure.

Inventive Principle:

Principle #10Preliminary action

3Strength

If the attachment weight is increased to reduce torsional load, then structural strength is improved, but the device complexity and cost increase

Engineering Contradiction:

Improveattachment strengthVSAvoidsystem complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The system replaces the mechanical solution of using a heavier attachment with a control-based solution. Instead of increasing mechanical strength through weight, the system uses sensors and controllers to actively manage the tree's position and lean, substituting mechanical mass with intelligent control to reduce torsional load.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9877437B2Felled tree lean control system and method

Publication Date: 2018.01.30 DEERE & CO

AI summary

A controlled lean system for a tree feller-buncher includes a sensor configured to measure an orientation of a boom coupled to the tree feller-buncher, and a felling head operably connected to the boom. A controller is operable to detect a cut tree carried by the felling head and to estimate a quantity of tree lean needed to reduce torsional load during rotation of the boom while carrying the cut tree based at least in part on the measured orientation of the boom.