Ship Roll Stabilisation via Precession Motion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing active stabilisation systems for ships, based on the Magnus effect, are inefficient due to the need for constant mass acceleration and deceleration, high energy demands, and limited functionality at high sailing speeds, with increased frictional resistance.
Innovation Solution
The system imparts a precession motion to the rotatable stabilisation element, allowing for simpler drive system design and extended duration of correction lift, with independent control of precession and rotation directions and speeds, and optional universal joint connection for effective movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If reciprocating translational movement is imparted to stabilisation elements, then correction force is generated for opposing ship's roll, but mass acceleration and deceleration make considerable demands on energy sources and complicate the drive system
Solution Approach 1:
The stabilisation element is configured to rotate about its longitudinal axis while simultaneously precessing about a transverse axis. This dynamic dual-motion configuration allows the element to generate Magnus effect forces more efficiently, reducing the energy required for mass acceleration and deceleration while maintaining effective roll compensation.
2Force
If reciprocating translational movement is imparted to stabilisation elements, then correction force is generated for opposing ship's roll, but the drive system requires constant change-overs and accumulators for smoothing peak currents
Solution Approach 1:
The stabilisation element performs simultaneous rotation about its longitudinal axis and precession about a transverse axis. This dynamic configuration eliminates the need for constant reciprocating movement and direction changes, thereby simplifying the drive system and removing the requirement for accumulators to smooth peak currents.
Solution Approach 2:
The precession motion creates a periodic pattern of force generation that is more evenly distributed over time, reducing peak current demands and eliminating the need for accumulators in the hydraulic drive system.
3Reliability
If stabilisation elements are used for roll compensation, then effective damping is achieved at low speeds, but frictional resistance increases at higher sailing speeds
Solution Approach 1:
The stabilisation element rotates about its longitudinal axis while precessing about a transverse axis. This dynamic dual-motion configuration optimizes the Magnus effect generation across a broader range of sailing speeds, reducing frictional resistance while maintaining effective roll compensation at higher 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 approach reduces energy consumption, maintains effective roll compensation, and enables operation at higher sailing speeds with reduced frictional resistance, enhancing the system's efficiency and adaptability.
Implementation Method 1
Under the influence of the rotational movement of the stabilisation element and the water flowing past as a result of the stabilisation element moving relative to the stationary ship, a correction force is generated perpendicular to the direction of rotation and the direction of movement. This physical phenomenon is also referred to as the Magnus effect
Implementation Method 2
the moving means are configured to impart a precession motion to the at least one rotatable stabilisation element in dependence on the ship's sailing speed and the control signals being delivered by the sensor means
Data Source
AI summary
The invention relates to a system for actively damping a ship's motion, comprising at least one first rotatable stabilization element extending from the ship's hull, below the water line, on a side of the ship, sensor means for sensing the ship's motion and delivering control signals on the basis thereof to driving means for rotatably driving the stabilization element for the purpose of damping the ship's motion being sensed, as well as moving means for moving the stabilization element relative to the ship. According to the invention, the active stabilization system is to that end characterized in that the moving means are configured to impart a precession motion to the at least one rotatable stabilization element in dependence on the ship's sailing speed and the control signals being delivered by the sensor means. Imparting a precession movement to the rotating stabilization elements obviates the need to constantly change the direction of the mass of the stabilization elements. Instead, only the direction of rotation of the stabilization elements needs to be constantly reversed and adjusted for speed.