Fin Stabilizer Harmonic Drive Torque Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional fin roll stabilizers for marine vessels rely on complex and maintenance-intensive hydraulic systems, which are prone to leaks, overheating, and fire risks, and also suffer from backlash and positioning errors in direct drive electric motor systems.
Innovation Solution
The use of a harmonic drive or walking/stepping drive system with oscillating teeth/gears that provide improved torque control and reduced or zero backlash, along with flexible motor and drive element placement and standardized components for adaptable fin and torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a hydraulic system is used to power the fin roll stabilizer, then sufficient power and torque control are achieved, but the system complexity increases with multiple components (pumps, valves, cylinders, hoses) and maintenance requirements
Solution Approach 1:
The patent extracts and eliminates the complex hydraulic components (pumps, valves, cylinders, hoses, reservoirs) from the stabilizer system, retaining only the essential function of powered fin rotation through direct electric motor coupling to the fin shaft
Solution Approach 2:
The patent replaces the hydraulic mechanical system with an electrical motor system that directly drives the fin shaft, substituting complex fluid power transmission with simpler electromagnetic actuation
2Reliability
If a hydraulic system is used, then the stabilizer can operate effectively, but environmental harm increases due to hydraulic oil leaks contaminating the ocean
Solution Approach 1:
The patent replaces the hydraulic fluid-based mechanical system with an electrical motor system that has no hydraulic oil, thereby eliminating the source of environmental contamination while maintaining the ability to effectively control fin rotation for stabilizer operation
3Device complexity
If direct drive electric motors with planetary gear sets are used, then hydraulic system complexity is reduced, but positioning precision deteriorates due to backlash and gear wear
Solution Approach 1:
The patent removes the planetary gear set and intermediate transmission components from the direct drive electric motor system, creating a direct coupling between the motor and fin shaft that eliminates gear backlash and positioning errors caused by gear wear
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 enhances the stability of marine vessels by providing improved torque control and reduced backlash, while also simplifying maintenance and reducing environmental and safety risks associated with hydraulic systems.
Implementation Method 1
a harmonic drive or other walking/stepping drive which utilizes oscillating teeth/gears which progressively step relative to an outer gear by incrementally walking around this relatively large internally toothed outer gear by virtue of a radial or oscillating motion component
Data Source
AI summary
A vessel hull stabilization system includes a housing having a rotatable shaft mounted thereto, the shaft configured to connect to a fin such that the fin is located on an outside of the vessel hull and the housing is located on an inside of the vessel hull. A drive system is mounted to the housing and includes a motor and a drive element. The motor is connected to a central shaft of the drive element. The drive element includes a plurality of teeth positioned between the outer element and the central shaft such that when the motor rotates the central shaft, the plurality of teeth oscillate inwards and outwards to interact with teeth in the outer element and thereby cause rotation of a fin shaft connected to the outer element or to the gear having the oscillating teeth. A controller receives sensor readings to determine control signals to send to the motor(s) to impart rotation of the fin.