Mobile Crane Stability Monitoring via Center of Gravity and Tipping Line Analysis
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Solution Overview
Problem
Existing mobile cranes face challenges in ensuring stability due to the complexity of calculating the overall center of gravity and tipping lines, particularly when the boom's rotation angle and extension length affect the crane's balance, leading to potential tipping hazards.
Innovation Solution
The mobile crane incorporates systems to determine the overall center of gravity and tipping lines, emitting alarms or halting movements if limits are approached, and uses force and position measurements from supports to assess stability, allowing for controlled slowing or stopping of operations to prevent tipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crane uses traditional stability check methods with multiple slewing ranges and uniform permissible boom moments, then the stability can be ensured, but the device complexity increases due to multiple tables and ranges
Solution Approach 1:
The patent changes the stability check parameters from uniform permissible boom moments in multiple slewing ranges to variable permissible boom moments based on actual outrigger positions. The stability check adapts to the specific configuration by calculating permissible moments according to the actual distance of the overall center of gravity from tipping lines, rather than using pre-defined uniform ranges.
Solution Approach 2:
The stability check system transitions from static pre-defined slewing ranges to a dynamic assessment that continuously adapts to the current outrigger positions and center of gravity location. The system dynamically calculates the distance from the overall center of gravity to tipping lines and adjusts permissible boom moments accordingly, making the stability check responsive to real-time configuration changes.
2Reliability
If the crane implements comprehensive stability monitoring with center of gravity determination and tipping line calculations, then the stability can be ensured, but the device complexity increases
Solution Approach 1:
The stability monitoring system utilizes data already available in the crane's control system, such as outrigger position sensors and existing center of gravity calculation capabilities. The system serves itself by using the same computational resources and sensor data already present in the crane, rather than requiring entirely separate monitoring hardware.
Solution Approach 2:
The stability check system serves multiple functions: it determines overall center of gravity position, calculates distance to tipping lines, assesses stability margins, and provides guidance for outrigger positioning. A single integrated system performs what would traditionally require multiple separate functions and tables.
3Reliability
If the crane uses fixed permissible boom moments for each slewing range, then the stability can be ensured, but the ease of operation decreases due to limited flexibility
Solution Approach 1:
The permissible boom moments transition from fixed values in pre-defined slewing ranges to dynamic values that automatically adjust based on actual outrigger positions and center of gravity location. The system dynamically recalculates permissible moments as outriggers are extended or repositioned, providing real-time guidance to the operator.
Solution Approach 2:
The stability check system provides continuous feedback to the operator about the current stability margin and permissible boom moments based on actual outrigger positions. The system monitors the distance from the overall center of gravity to tipping lines and adjusts permissible moments accordingly, creating a closed-loop control system that guides operational decisions.
Data Source
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AI summary
The crane has an identification unit to determine a total center of gravity of the crane. A determination unit determines an inclined line of the crane. A stability ensuring unit provides a signal and/or prevents crane movement, when distance of the center of gravity from the line reaches or approximates or exceeds a threshold value and/or when a ratio of a distance of the center of gravity from a rotating assembly midpoint to distance of the line from the midpoint reaches or approximates or exceeds the threshold value. A sliding rail (1) and a pad cylinder (2) are provided in the crane.