Forestry Harvesting Head Trunk Thickness Measurement Deviation Compensation
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Solution Overview
Problem
Existing methods for determining the thickness of a tree trunk in a harvesting head for forestry are inaccurate due to deviations from the reference surface, leading to incorrect volume calculations.
Innovation Solution
A method and harvesting head that utilize a tree trunk surface follower and a proximity sensor to measure the deviation of the trunk from the reference surface, allowing for a corrected thickness calculation by adjusting for this deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the tree trunk is pressed against the reference surface at all times to ensure measurement accuracy, then the thickness determination accuracy is improved, but the power consumption increases and the limbing process speed decreases
Solution Approach 1:
The system performs preliminary measurement of the deviation from the reference surface before the thickness determination. By measuring the deviation first using the deviation measuring arrangement, the system can compensate for positional inaccuracies during the subsequent thickness measurement, eliminating the need for continuous pressing against the reference surface and thereby improving both accuracy and speed
Solution Approach 2:
The system uses feedback from the deviation measuring arrangement to adjust the thickness measurement. The measured deviation is fed back into the control system, which then compensates for the positional error in the thickness measurement, allowing accurate measurements without requiring the trunk to be pressed against the reference surface
2Measurement precision
If the tree trunk is pressed against the reference surface at all times to ensure measurement accuracy, then the thickness determination accuracy is improved, but the power consumption increases
Solution Approach 1:
The system performs preliminary measurement of the deviation from the reference surface before the thickness determination. By measuring the deviation first using the deviation measuring arrangement, the system can compensate for positional inaccuracies during the subsequent thickness measurement, eliminating the need for continuous pressing against the reference surface and thereby improving both accuracy and speed
Solution Approach 2:
The system uses feedback from the deviation measuring arrangement to adjust the thickness measurement. The measured deviation is fed back into the control system, which then compensates for the positional error in the thickness measurement, allowing accurate measurements without requiring the trunk to be pressed against the reference surface
Data Source
Figure 1a~1b
Figure 2
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AI summary
The present invention relates to a method for determining a thickness of a tree trunk (17) in a harvesting head (1) for forestry, said harvesting head (1) comprising a tree trunk pressing device (3, 4, 7, 8), and a tree trunk surface follower (11, 11'), wherein the tree trunk surface follower is a limbing member (11, 11'), and wherein the limbing member (11, 11') is curved, said method comprising pressing the tree trunk (17), with said tree trunk pressing device (3, 4, 7, 8), in a direction towards a reference surface (15) of the harvesting head (1) and determining a measured thickness (T) by measuring the position of the tree trunk pressing device (3, 4, 7, 8) and relating said position to said reference surface (15), said method further comprising the steps of determining a deviation (D) of the tree trunk (17) from said reference surface (15) by measuring a position of the tree trunk surface follower (11, 11') and relating said position of the tree trunk surface follower (11, 11') to said reference surface (15), and calculating a corrected thickness (Tc) of the tree trunk (17) based on said measured thickness (T) and said deviation (D), wherein determining the deviation (D) further comprises relating said position of the tree trunk surface follower (11, 11') to said measured thickness (T).