Counter-Rotating Underwater Propulsion with Servo-Swashplate Actuation
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Solution Overview
Problem
Current underwater vehicles face limitations in combining high-speed agility with omnidirectional capability and precision, particularly in turbulent environments, where traditional AUVs are too fast but lack maneuverability, and ROVs are too slow and susceptible to flow-based disturbances.
Innovation Solution
A high-speed omnidirectional underwater propulsion mechanism featuring counter-rotating blades with a servo-swashplate actuation system, allowing for decoupled blade-pitch actuator loads from rotor torques, enabling quick reaction to disturbances and exceptional maneuverability by exploiting moving water properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional AUVs are used for high-speed operation, then speed is improved, but maneuverability and omnidirectional capability deteriorate
Solution Approach 1:
The propulsion system is segmented into multiple independent counter-rotating blade assemblies, each capable of independent pitch control. This segmentation allows the vehicle to generate thrust in multiple directions simultaneously, achieving omnidirectional movement while maintaining high speed capability.
Solution Approach 2:
The blade pitch angles are made dynamically adjustable through servo actuators that can rapidly change blade orientation in response to control inputs. This dynamic adjustment enables the system to transition between different motion modes (forward propulsion, lateral movement, rotation) without sacrificing speed or maneuverability.
2Ease of operation
If traditional ROVs are used for omnidirectional capability, then maneuverability is improved, but speed deteriorates
Solution Approach 1:
The system merges the omnidirectional control capability of ROVs with the high-speed propulsion characteristics of AUVs by combining multiple counter-rotating blade assemblies with independent pitch control into a single integrated propulsion system.
Solution Approach 2:
Each blade assembly serves multiple functions: generating forward thrust, enabling lateral movement, and providing rotational control. This multi-functionality allows the vehicle to achieve full omnidirectional capability while maintaining high speed through the same propulsion elements.
3Device complexity
If traditional propulsion systems are used in turbulent environments, then simplicity is maintained, but reaction time to disturbances increases
Solution Approach 1:
The dynamic blade pitch control system allows for rapid adjustment of thrust vectors in response to environmental disturbances. The servo actuators can quickly change blade angles to counteract external forces, providing fast reaction time while maintaining a relatively simple overall system architecture.
Solution Approach 2:
The system incorporates feedback control mechanisms that continuously monitor vehicle position and orientation, comparing actual state with desired state to generate corrective control signals. This feedback loop enables automatic compensation for disturbances with minimal reaction time.
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 a submersible with unprecedented speed, agility, and omnidirectional capability, capable of operating in extreme environments with reduced operating time and cost, by minimizing reaction time to disturbances and maintaining high power efficiency.
Implementation Method 1
The propulsion mechanism includes a first set of counter rotating blades including a plurality of pivotable blades centered around a hollow stationary structural tubing
Implementation Method 2
A blade-axis re-enforcing flap adapter (BARFA) includes a plurality of stationary flaps and positioned between the counter rotating rotors
Data Source
AI summary
Various examples of a high-speed omnidirectional fully-actuated underwater propulsion mechanism are described. In one example, a propulsion system includes two decoupled counter-rotating rotors centered on a main axis, with each rotor comprising a plurality of pivotable blades projecting radially from the main axis, a servo-swashplate actuation mechanism comprising a plurality of servos and a linkage assembly connected from the servos to the pivotable blades, a blade-axis re-enforcing flap adapter comprising a plurality of stationary flaps, with the blade-axis re-enforcing flap adapter being positioned in a region between the two decoupled counter-rotating rotors centered on the main axis, and a controller. The controller can be configured to calculate control parameters, compensate a first control parameter among the control parameters to reduce cross-coupling of an unwanted force generated by drag forces on the two decoupled counter-rotating rotors, and generate a control signal for each of the servos based on the control parameters.