Underwater Vehicle Vector Control Assemblies for Six-DOF Stability
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Solution Overview
Problem
Current submersible vehicles, such as AUVs and ROVs, face instability and loss of positional control due to Munk moment, require multiple thrusters and external control planes, and struggle with maintaining position in dynamic environments, especially when ocean currents exceed minimum forward motion requirements.
Innovation Solution
A propulsion and directional control system using two thrusters with vectoring control assemblies, one at the bow and one at the stern, allowing six degrees of freedom control without external control planes, by independently adjusting damper assemblies to regulate water flow for precise positional control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple thrusters and external control planes are used to counter Munk moment and maintain stability, then vehicle stability improves, but device complexity increases
Solution Approach 1:
The patent combines the functions of multiple separate control surfaces and control plane operations into a single integrated vectoring control assembly. This assembly uses a single thruster with a controllable flow director that can redirect thrust in multiple directions (surge, sway, heave) to achieve six degrees of freedom control, eliminating the need for multiple external control planes and reducing overall system complexity while maintaining stability
Solution Approach 2:
The vectoring control assembly is designed to perform multiple control functions simultaneously. A single thruster with a flow director can generate thrust for forward motion while also providing directional control in three axes (surge, sway, heave), making the system multi-functional and replacing what would traditionally require multiple separate control surfaces and thrusters
2Ease of operation
If external control planes are used for directional control, then directional control capability improves, but drag increases
Solution Approach 1:
The patent removes external control planes from the vehicle design entirely. Instead of using separate control surfaces that protrude into the water flow, the invention extracts the directional control function and integrates it into the thrust system itself through the vectoring control assembly, which redirects thrust internally without requiring external protruding surfaces
Solution Approach 2:
The patent replaces the mechanical control plane system with a flow redirection mechanism. Instead of using physical control surfaces that move to change direction, the invention uses a flow director that actively redirects the thrust flow in three dimensions, substituting a flow-based control mechanism for traditional mechanical control planes
3Ease of operation
If forward motion is maintained above minimum speed to generate flow over control planes, then positional control improves, but energy consumption increases
Solution Approach 1:
The vectoring control assembly provides dynamic control capability that works across a wide range of forward speeds. By redirecting thrust flow rather than relying on flow over control planes, the system maintains effective positional control even at low forward speeds or when stationary, eliminating the need to maintain minimum speed for control surface effectiveness
Solution Approach 2:
The system uses its own thrust to provide directional control without requiring separate control surfaces. The flow director redirects the thrust generated by the main propeller to provide control forces, allowing the vehicle to control its own position using its propulsion system itself, eliminating the need for additional energy-consuming control plane actuators
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
Enhances vehicle stability, reduces drag, improves positional control in dynamic conditions, and enables efficient station keeping, even in the presence of ocean currents, while minimizing protrusions for improved maneuverability and safety.
Implementation Method 1
a single thruster assembly... consists of any one of various types of electric or fuel motor that provide power to a drive shaft that, in turn rotates a propeller mounted thereto
Implementation Method 2
The movement of the planes causes water resistance against the movement of the vehicle body in the water column, thereby forcing the vehicle to change direction
Implementation Method 3
The d'Alembert's paradox predicts zero net force, but not necessarily a zero moment. This, so-called, Munk moment arises because of asymmetric location of the stagnation points, where pressure is highest on the front of the body (decelerating flow) and lowest on the back (accelerating flow)
Data Source
AI summary
A submersible vehicle is provided which is able to achieve six of freedom utilizing a combination of only two thrusters with no external control planes. Each of the two thrusters can include a plurality of ducts which can be selectively opened or closed, to varying degrees, to achieve six degrees of freedom for both control and propulsion.