ROV Docking Station Motion Compensation in Shallow Water
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Solution Overview
Problem
The launching and recovery of remotely operated vehicles (ROVs) near the sea surface are hindered by motion interference from wave particle motion and pressure fluctuations, which can damage the ROV, docking station, and launch and recovery system (LARS), as existing active heave compensation (AHC) is ineffective in shallow water conditions.
Innovation Solution
An active motion compensation system that synchronizes the motion of a docking station with the ROV by receiving information on particle motion from motion sensors, including inertial sensing systems, flow sensors, and wave motion sensors, and adjusts the crane's actuators to counteract the vessel and ROV movements, ensuring the docking station remains stationary relative to the ROV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If active heave compensation (AHC) is used to stabilize the docking station, then the stability of the docking station is improved, but it becomes ineffective in shallow water conditions where wave particle motion affects the ROV
Solution Approach 1:
The system uses motion sensors to detect the ROV's position and wave-induced motion in real-time, then feeds this information back to the crane control system. The control system continuously adjusts the crane's actuators based on this feedback to synchronize the docking station's motion with the ROV's motion, maintaining stability even in shallow water conditions where traditional AHC fails.
Solution Approach 2:
The system transitions from a static stabilization approach (traditional AHC) to a dynamic motion synchronization approach. The crane's actuators are dynamically adjusted in real-time to match the ROV's wave-induced motion, allowing the docking station to move with the ROV rather than resisting the motion, thereby maintaining effectiveness in shallow water.
2Ease of operation
If the docking station is kept stationary relative to the vessel, then the launching and recovery operations are simplified, but wave particle motion and pressure fluctuations cause relative motion between the docking station and ROV, risking damage
Solution Approach 1:
The system converts the harmful wave-induced motion of the ROV into a beneficial synchronization signal. By detecting the ROV's motion and using it to control the crane's actuators, the docking station moves in sync with the ROV, transforming the potential hazard of relative motion into a controlled coordinated motion that eliminates the harmful effects.
Solution Approach 2:
The crane's actuators serve as an intermediary between the vessel and the docking station. They transmit and adjust the motion from the vessel to the docking station, allowing the docking station to follow the ROV's motion while maintaining a controlled connection, thus eliminating harmful relative motion without completely isolating the docking station from the vessel.
3Reliability
If motion sensors and active compensation systems are added to counteract wave effects, then the safety and stability of ROV operations are improved, but the system complexity increases
Solution Approach 1:
The crane's actuators perform multiple functions: they traditionally position the docking station during launching and recovery, and now also actively compensate for wave-induced motion by synchronizing with the ROV. This multi-functionality reduces the need for separate compensation equipment, thereby limiting the increase in system complexity while maintaining improved safety and reliability.
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
This system effectively minimizes relative vertical motion between the docking station and the ROV, improving the stability and safety of launch and recovery operations by aligning the docking station's motion with the ROV's motion, even in shallow water conditions, thus reducing the risk of damage and enhancing operational efficiency.
Implementation Method 1
receive a measurement corresponding to a particle motion in water surrounding a remotely operated vehicle (ROV)
Implementation Method 2
synchronizes a motion of a docking station with a motion of the ROV based at least in part on the measurement corresponding to the particle motion
Data Source
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AI summary
Certain aspects of the present disclosure generally relate to motion compensation between water-borne objects, and, more particularly, to synchronizing motion between a remotely operated vehicle (ROV) (206) and a docking station (220) of a launch and recovery system (LARS) (204). An exemplary method includes receiving a measurement corresponding to a particle motion in water surrounding an ROV and synchronizing motion of a docking station with a motion of the ROV based at least in part on the measurement corresponding to the particle motion.