Heave-Compensating Boom for Knuckle-Boom Crane Upgrade
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Solution Overview
Problem
Existing heave-compensating cranes are not suitable for heavy-duty hoisting, as they lack sufficient motion compensation capacity and speed in the X and Y directions, particularly when handling loads over 50 T, due to their complex structure with multiple bends which reduces weight motion-compensating capacity.
Innovation Solution
Upgrading a knuckle-boom crane by replacing the knuckle-boom with a main boom extension and a heave-compensating boom oriented downwards, which is pivotable in both horizontal directions, and incorporating a winch-based heave-compensation system to separately manage vertical variations, thereby maximizing motion compensation capacity and speed in the X and Y directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a complex structure with multiple bends is used in existing heave-compensating cranes, then the crane can handle loads, but the weight motion-compensating capacity and speed in X and Y directions is reduced
Solution Approach 1:
The crane structure is divided into distinct functional segments: a main boom for vertical lifting, a heave-compensating boom for horizontal motion compensation, and separate control systems. This segmentation allows each component to be optimized for its specific function, improving motion compensation speed while managing complexity through modular design.
Solution Approach 2:
The invention introduces a downwardly extending heave-compensating boom that operates in horizontal dimensions (X and Y) separate from the vertical lifting function. This dimensional separation allows independent optimization of horizontal motion compensation without compromising vertical lifting capability, thereby improving overall compensation speed while structuring complexity across different spatial dimensions.
2Weight of moving object
If existing heave-compensating crane systems are used, then basic heave compensation is achieved, but sufficient motion compensation capacity for heavy loads over 50 T is not provided
Solution Approach 1:
The heave-compensating boom is designed with active dynamic control capabilities, allowing real-time adjustment of orientation and position in response to wave-induced motions. This dynamic adaptability enables the system to maintain reliable motion compensation for heavy loads by continuously optimizing the boom's configuration rather than relying on static structural support.
Solution Approach 2:
The downwardly extending heave-compensating boom acts as an intermediary mechanism between the main lifting system and the load. It provides a dedicated interface for horizontal motion compensation, isolating the heavy load handling function from the motion compensation function and thereby ensuring reliable compensation capacity independent of load weight.
3Productivity
If the knuckle-boom is replaced with a main boom extension and heave-compensating boom, then motion compensation capacity in X and Y directions is maximized, but the structural configuration becomes more complex
Solution Approach 1:
The main boom extension serves multiple functions: it extends the reach of the crane while providing the mounting structure for the heave-compensating boom. This multi-functionality reduces the need for additional separate structural elements, thereby maximizing motion compensation capacity while limiting the increase in overall structural complexity.
4Use of energy by moving object
If a winch-based heave-compensation system is used to manage vertical variations separately, then energy injection into the motion compensation system is increased, but the system becomes more complex
Solution Approach 1:
The heave-compensation system is segmented into two independent subsystems: a winch-based system for vertical (Z-direction) compensation and a heave-compensating boom system for horizontal (X and Y-direction) compensation. This segmentation allows each subsystem to be optimized and controlled independently, enabling increased energy injection into the horizontal compensation system without creating intertwined control complexities.
Data Source
AI summary
A method of upgrading a knuckle-boom crane to a heave-compensating crane includes: removing a knuckle-boom from a main boom; mounting a main boom extension to the main boom for increasing the length of the main boom; and mounting a heave-compensating boom at a far end of the main boom extension such that the heave-compensating boom extends in a downward vertical direction (Z) in operational use of the heave-compensating crane. The heave-compensating boom is configured to be pivotable with respect to the main boom extension in both horizontal directions (X, Y). A heave-compensation system is provided to the knuckle-boom crane, wherein the heave-compensation system compensates for horizontal variations by controlling the orientation of the heave-compensating boom relative to the main boom extension, and compensates for vertical variations by means of a further vertical heave-compensation system, such as a winch-based heave-compensation system.