Work Machine Fall Evaluation Using Directional Energy Margins
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Solution Overview
Problem
Existing fall evaluation methods for work machines, such as hydraulic excavators, do not adequately consider the relationship between swing operations and falling directions, leading to potential inaccuracies in assessing the stability and risk of falling.
Innovation Solution
A fall evaluation system and method that calculates an energy stability margin for each side of the support polygon of a work machine, considering the center-of-gravity position and swing operation, to evaluate the possibility of falling by determining the energy required to cause the machine to fall when a side serves as a rotation axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ZMP calculation method is used to evaluate falling possibility, then the evaluation can be performed based on moment balance, but the evaluation becomes inaccurate when the machine body is lifted by inertia force
Solution Approach 1:
The patent changes the evaluation parameter from ZMP (zero moment point) based on moment balance to energy stability margin based on potential energy differences. This parameter transformation allows the system to accurately evaluate falling possibility even when the machine body is lifted by inertia forces, as energy-based evaluation remains valid under dynamic conditions where moment-based evaluation fails
2Adaptability or versatility
If a general fall evaluation method is used, then the evaluation can be performed for static conditions, but it cannot accurately assess falling risk in various directions during swing operations
Solution Approach 1:
The patent segments the support polygon into multiple sides and calculates the energy stability margin for each side independently. This segmentation allows the system to evaluate falling risk in different directions (corresponding to different sides of the support polygon) separately, providing comprehensive coverage for swing operations while maintaining high precision for each specific falling direction
Solution Approach 2:
The patent introduces directional dimensionality by evaluating energy stability margins for each side of the support polygon separately. This transforms a single scalar stability measure into a multi-dimensional assessment that captures falling risks in different directions, enabling accurate risk assessment during swing operations where the machine may fall in various directions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides accurate assessments of falling risks in various directions, allowing for timely warnings and operational adjustments to prevent accidents by considering the dynamic changes in the support polygon due to swing operations.
Implementation Method 1
a center-of-gravity position calculation unit configured to calculate a center-of-gravity position of the work machine
Implementation Method 2
an energy calculation unit configured to calculate an energy amount for each of a plurality of sides of a support polygon of the work machine, the energy amount being required to cause the work machine to fall when the side serves as a rotation axis
Data Source
AI summary
An energy calculation unit calculates an energy amount for each of a plurality of sides of a support polygon of a work machine in which the energy amount is required to cause the work machine to fall when the side serves as a rotation axis. An evaluation unit evaluates a possibility of the work machine falling based on the calculated energy amount for each of the sides.