Subsea ROV Attachment Mechanisms for Passive Stability Holding
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Solution Overview
Problem
Remotely operated vehicles (ROVs) face challenges in maintaining stability during subsea inspections and cleaning tasks, especially on suspended structures, due to reaction forces that destabilize them, leading to increased thruster use, battery depletion, and operational delays.
Innovation Solution
The development of attachment mechanisms that secure ROVs to subsea structures using motorized grasping hooks, worm gear drive systems, and spring-loaded swing arms to passively counteract destabilization forces, reducing thruster reliance and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thrusters are activated to counteract reaction forces, then ROV stability is improved, but battery power is depleted and operational time is reduced
Solution Approach 1:
The invention extracts the stabilization function from the thruster system and relocates it to a mechanical attachment mechanism. The grasping hooks with worm gear drives provide passive mechanical stabilization, removing the need for continuous thruster activation and thereby reducing battery power consumption while maintaining ROV stability during inspection operations
Solution Approach 2:
The invention replaces the active mechanical system (thrusters requiring continuous power) with a passive mechanical system (grasping hooks with worm gear drives). The worm gear mechanism provides self-locking capability that maintains attachment force without continuous power input, substituting active thruster-based stabilization with passive mechanical stabilization
2Stability of the object's composition
If thrusters are continuously activated to maintain stability, then ROV position is maintained, but operational time and productivity are reduced
Solution Approach 1:
The invention applies preliminary action by pre-attaching the grasping hooks to the subsea structure before inspection tasks begin. The worm gear drives advance the hooks to engage with the structure surface in advance, establishing mechanical stabilization before reaction forces from cleaning or inspection tools are applied, thereby eliminating the need for continuous thruster corrections during operations
Solution Approach 2:
The attachment mechanism provides self-service stabilization through the self-locking property of the worm gear drives. Once the hooks are advanced and engaged with the subsea structure, the worm gear mechanism maintains the attachment force automatically without requiring continuous power input or active control, enabling the ROV to stabilize itself passively during inspection operations
3Use of energy by moving object
If mechanical attachment mechanisms are used to stabilize ROV, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The invention segments the stabilization function into separate modular components: a pair of independent grasping hooks, each with its own worm gear drive system. This segmentation allows the complex mechanical attachment mechanism to be broken down into manageable modules that can be independently controlled and maintained, reducing the overall system complexity while providing effective passive stabilization
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 attachment mechanisms effectively maintain ROV stability with minimal power consumption, reducing thruster use and preserving battery life, while allowing for secure attachment to various subsea structures without reorientation, thus improving inspection and cleaning efficiency.
Implementation Method 1
a worm screw, a wormshaft, a worm wheel... the worm screw having a plurality of teeth disposed along its outer circumference and driven by the generated rotational force to rotate... the worm wheel being circumferentially throated to mesh with the plurality of teeth of the worm screw
Implementation Method 2
a first pair of bevel gears coaxially disposed at each end of the wormshaft... the external teeth of the first pair of bevel gears and the external teeth of the second pair of bevel gears mesh at a meshing angle
Implementation Method 3
a spring means disposed between the mechanical stop and the swing arm, thereby providing a tension force to the swing arm
Implementation Method 4
a swing arm coupled to the rigid holder at the pivot point, the swing arm having a rolling element embedded therein
Data Source
AI summary
Systems and methods for securing a remotely operated vehicle (ROV) to a subsea structure during cleaning, maintenance, or inspection of the structure surface are provided. In one or more embodiments, an attachment mechanism includes a pair of grasping hooks that are raised and lowered when driven by a motorized drive. In one or more embodiments, an attachment mechanism includes a rigid holder having a mechanical stop and connected to a swing arm, the swing arm configured to rotate inward, but not outward beyond the mechanical stop. In one or more embodiments, an attachment mechanism includes a plurality of linked segments in series, each connected at a plurality of pivot points. A pair of wires passes through the plurality of linked segments and connects to a pair of pulleys that extend or retract the wires, thereby rotating the plurality of linked segments.