Articulated Variable-Pitch Propellers for Underwater Thrust Vectoring
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Solution Overview
Problem
Current underwater vehicle propulsion and control systems, such as those using Haselton-type tandem propellers, are limited in maneuverability and thrust-vectoring capability, particularly at low speeds and for sideward translational motion, due to their non-articulated and fixed blade pitch design.
Innovation Solution
The implementation of articulated, variable-pitch tandem fore-and-aft coaxial contra-rotating propellers that allow cyclic and collective blade pitch control, combined with flapping and lead-lag articulation, enabling enhanced control and maneuverability in six degrees of freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional rigid propellers are used, then good thrust is achieved, but lateral and off-axis control is poor
Solution Approach 1:
The propeller blade is segmented into multiple sections with independent pitch control capability. Each blade section can be rotated independently about its longitudinal axis, allowing differential pitch adjustment between sections. This segmentation enables the propeller to generate both thrust and lateral/off-axis control forces by coordinating the pitch angles of different blade sections.
Solution Approach 2:
The propeller system transitions from a static fixed-pitch design to a dynamic variable-pitch system. The blade pitch angles can be changed during operation through actuation mechanisms, allowing real-time adjustment of thrust and control forces. This dynamic capability enables the propeller to adapt to different operational requirements and provide effective lateral and off-axis control.
2Ease of operation
If additional control devices like rudders and planes are added, then lateral control is improved, but the system becomes more complex and ineffective at low speeds
Solution Approach 1:
The propeller blade is designed to perform multiple functions simultaneously: generating thrust, providing lateral control, and enabling off-axis maneuvering. By integrating control surfaces and actuation mechanisms directly into the propeller blade structure, the system eliminates the need for separate rudders and planes. This multi-functionality reduces overall system complexity while maintaining effective control at all speeds including low speeds.
Solution Approach 2:
The control functions that were previously separate (propulsion and steering) are merged into a single integrated propeller system. The blade pitch control mechanism combines thrust generation and lateral control capabilities in one component, reducing the number of separate devices needed and simplifying the overall system architecture.
3Ease of operation
If thrusters are implemented for multi-axis control, then control capability is improved, but axis-independent units are required and high-speed efficiency is reduced
Solution Approach 1:
The propeller blade is divided into controllable segments that can be independently pitched. This segmentation allows the generation of multi-axis control forces (lateral, roll, pitch, yaw) through coordinated pitch adjustments of individual blade sections, eliminating the need for separate axis-independent thrusters while maintaining high-speed efficiency.
Solution Approach 2:
The system controls multi-axis motion by changing the pitch angle parameters of the propeller blade sections. By varying the pitch angles of different blade segments independently, the system can generate the necessary forces and moments for multi-axis control without requiring additional thrusters, thereby maintaining propeller efficiency at high speeds.
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 solution provides improved multi-directional off-axis forces and thrust vectoring, allowing underwater vehicles to translate and rotate in any direction regardless of speed, enhancing precision and mission capabilities, such as precision station keeping and variable-angle positioning.
Implementation Method 1
a marine propeller... Each blade is controllable in pitch angle... The propeller is for rotation in a body of water
Implementation Method 2
flapping and lead-lag articulation, enabling enhanced control and maneuverability
Implementation Method 3
Cyclic blade control changes the pitch angle of each propeller blade in accordance with the blade position in a cycle
Implementation Method 4
Collective blade control changes the pitch angle of all of the propeller blades equally and simultaneously
Data Source
AI summary
According to typical inventive practice, a cylindrical or prolate spheroidal marine hull has two congruent contra-rotative propellers coaxially situated at or near its axial ends. Each propeller has plural blades mechanically and/or flexibly attributed with changeability of blade pitch angles and blade flap angles. A blade-pitch control system adjusts the individual blade pitch angles of both propellers. The blade-pitch control system may be electronically and/or mechanically actuated, and is capable of: (i) cyclically adjusting the blade pitch angles of the two propellers so as to select two respective blade-tip-path planes, each characterized by a direction of thrust that is associated with the blade flap angles and is generally perpendicular to the blade-tip-path plane; (ii) collectively adjusting the blade pitch angles of the two propellers so as to select two respective magnitudes of thrust. The cyclic and collective blade commands, algorithmically coordinated, determine the direction, orientation, and speed of the hull.