Motion-Stabilized Crane Hook Control for Offshore Load Sway
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Solution Overview
Problem
Crane systems on offshore vessels face challenges in stabilizing loads due to uncontrolled movements caused by wave action, posing safety risks to personnel and equipment, and conventional methods like tug lines increase operational costs and expose crew to hazards.
Innovation Solution
A motion-stabilized crane system with a motion stabilizer featuring a hook housing, linear actuators, and optical sensors to automatically counteract uncontrolled motion of the hoisting cable and hook, minimizing angular deviation from the vertical axis using a stabilizer control module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tug lines are used for manual stabilization, then crew can stabilize loads, but operational costs increase and crew exposure to hazards increases
Solution Approach 1:
The motion stabilizer system enables self-service stabilization by using automated sensors and actuators to counteract vessel movements and stabilize the load without requiring manual intervention from crew members. The system autonomously monitors hook position and cable angle, then activates actuators to maintain vertical alignment, eliminating the need for tug lines and manual stabilization operations.
Solution Approach 2:
The patent replaces the mechanical tug line stabilization system with an automated electromechanical motion stabilizer. Instead of using ropes and manual pulling forces, the system uses sensors to detect motion and electric actuators to generate counteracting forces, substituting manual mechanical operations with automated sensor-actuator systems.
2Reliability
If manual stabilization methods are used, then loads can be stabilized, but safety risks to personnel increase
Solution Approach 1:
The motion stabilizer system enables self-service stabilization by using automated sensors and actuators to counteract vessel movements and stabilize the load without requiring manual intervention from crew members. The system autonomously monitors hook position and cable angle, then activates actuators to maintain vertical alignment, eliminating the need for tug lines and manual stabilization operations.
3Reliability
If motion stabilizer with actuators and sensors is implemented, then load stabilization is improved, but device complexity increases
Solution Approach 1:
The motion stabilizer integrates multiple functions into a single device: it houses both the sensing system (optical sensors, IMUs) and the actuation system (linear actuators, telescoping actuators) within one integrated structure mounted on the crane boom. This multi-functional integration reduces overall system complexity compared to having separate stabilization systems.
Solution Approach 2:
The system implements closed-loop feedback control where sensors continuously monitor hook position and cable angle, the control system processes this information, and actuators automatically adjust to maintain vertical alignment. This automated feedback mechanism eliminates the need for manual stabilization operations and reduces operational complexity despite adding sensing and actuation components.
4Object-affected harmful factors
If automated motion stabilization is used, then crew exposure to hazards is reduced, but manufacturing complexity increases
Solution Approach 1:
The motion stabilizer integrates multiple functions into a single device: it houses both the sensing system (optical sensors, IMUs) and the actuation system (linear actuators, telescoping actuators) within one integrated structure mounted on the crane boom. This multi-functional integration reduces overall system complexity compared to having separate stabilization systems.
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 effectively stabilizes loads during transport, enhancing safety by reducing the need for manual stabilization and minimizing crew exposure to suspended loads, while optimizing crane operation.
Implementation Method 1
a linear actuator coupled to the hook housing and configured to rotate the hook housing about a first axis in response to the activation of the linear actuator
Implementation Method 2
an optical sensor coupled to the hook housing and configured to capture as a sensor output associated with the position of at least one of the hook and the hoisting cable in the hook housing
Implementation Method 3
a stabilizer control module configured to activate the linear actuator to counteract an uncontrolled motion of at least one of the hook and the hoisting cable based on the sensor output produced by the optical sensor
Implementation Method 4
the motion stabilizer further comprises a telescoping actuator coupled to the hook housing and configured to displace the hook housing along the vertical axis in response to the activation of the telescoping actuator, and the stabilizer control module is configured to activate the telescoping actuator to maintain a tension on a terminal end of the hoisting cable
Implementation Method 5
the hook housing of the motion stabilizer comprises a plurality of circumferentially spaces sheaves which engage the hoisting cable to align a segment of the hoisting cable positioned between the plurality of sheaves with the vertical axis
Data Source
AI summary
A motion-stabilized crane system includes a crane base extending from a first end to a second end opposite the first end, a crane boom having a first end pivotably coupled to the second end of the crane base and a second end opposite the first end, a hoisting cable, a hook, a motion stabilizer including a hook housing in which at least one of the hoisting cable and the hook is received, a linear actuator configured to rotate the hook housing about a first, a sensor configured to capture as a sensor output associated with the position of at least one of the hook and the hoisting cable in the hook housing, and a stabilizer control module configured to activate the linear actuator to reduce an angle formed between at least one of the hook and the hoisting cable and a vertical axis based on the senor output.