Rig Supply Handler Motion Compensation for Offshore Cargo Transfer
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Solution Overview
Problem
Conventional cargo transfer methods between moving platforms, such as offshore platforms and Offshore Supply Vessels, pose significant safety hazards due to wave-induced motions, leading to wild container movements and potential damage, as they require manned intervention and rely on non-compensated crane systems.
Innovation Solution
A device comprising a removable manipulator and control system that attaches to the crane jib, enabling controlled 4 DOF motion compensation, allowing for safe and automated cargo transfer without crew members on the deck, using sensors and drive signals for real-time synchronized motion tracking and payload management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional non-compensated crane is used for cargo transfer, then the crane structure is simple and easy to operate, but the cargo moves wildly due to wave-induced motions creating safety hazards
Solution Approach 1:
A manipulator assembly is introduced as an intermediary device between the crane and the cargo. This manipulator includes a docking head with latch mechanism that automatically engages with the cargo container, serving as a mediator that eliminates the need for crew members to manually handle cargo on the moving deck, thereby resolving the safety hazard while maintaining operational simplicity
Solution Approach 2:
The manipulator assembly performs self-service functions through automated latch mechanisms that automatically engage and disengage from cargo containers. The system uses sensors to detect cargo position and automatically adjusts the manipulator position, eliminating the need for continuous manual intervention and reducing safety risks associated with crew members working on moving decks
2Reliability
If crew members manually handle the hook and cargo on deck, then the operation is simple and direct, but significant safety hazards are created due to wave-induced motions
Solution Approach 1:
The manipulator assembly performs self-service functions through automated latch mechanisms that automatically engage and disengage from cargo containers. The system uses sensors to detect cargo position and automatically adjusts the manipulator position, eliminating the need for continuous manual intervention and reducing safety risks associated with crew members working on moving decks
Solution Approach 2:
Manual mechanical handling by crew members is replaced with an automated manipulator system. The manipulator uses mechanical actuators and latch mechanisms controlled by sensors and automation systems, substituting human-operated mechanical systems with automated ones to eliminate safety hazards while improving operational efficiency
3Strength
If containers are lowered using nearby containers for impact support, then the crane structure remains simple, but damage occurs to the container being lowered or the containers on deck
Solution Approach 1:
The manipulator docking head serves as an intermediary between the crane lift hook and the cargo container. It provides a dedicated engagement interface with latch mechanisms that securely hold the cargo, eliminating the need to use nearby containers as impact supports and preventing damage to both the lowered container and the containers already on deck
Solution Approach 2:
The manipulator system provides self-service cargo handling capabilities with automated positioning and latching functions. The system uses sensors to detect cargo position and automatically adjusts the manipulator to achieve proper alignment and secure engagement, eliminating the need for manual intervention and preventing container damage through controlled, automated operations
4Manufacturing precision
If the crane operator manually aligns and places cargo on the moving deck, then the control system remains simple, but alignment precision is poor and nearby containers are impacted
Solution Approach 1:
The manipulator system incorporates sensors that provide real-time feedback on cargo position, manipulator position, and relative motion between the crane platform and the supply vessel. This feedback is used by the control system to automatically adjust the manipulator position and achieve precise alignment with the cargo container, enabling accurate placement without impacting nearby containers
Solution Approach 2:
The manipulator system is designed with dynamic motion compensation capabilities that actively adapt to the relative motions between the crane platform and the supply vessel. The system uses real-time sensor data to dynamically adjust the manipulator position and orientation, maintaining precise alignment despite wave-induced motions, thereby achieving accurate cargo placement while preventing damage to nearby containers
Data Source
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AI summary
A method of controlling a crane and a manipulator including determining the relative motion between a first platform including the crane and a second platform, determining the current position of the manipulator, and repositioning the manipulator to compensate for the relative motion between the first platform and the second platform and in accordance with operator commands.