Vessel Propulsion Unit Vibration Control via Motor Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling vibrations in propulsion units of vessels rely on external actuators, which are not always effective in managing vibrations originating from various sources, including rotating masses, propeller blades, water flow, and adjacent propulsion units, especially when exposed to oblique water flows.
Innovation Solution
A novel method that utilizes measuring devices to generate an auxiliary torque control signal, which is added to the torque control signal of the electric motor, allowing for counteraction against measured vibrations within the electric motor itself, eliminating the need for external actuators and effectively addressing vibrations in multiple directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If external actuators are used to produce counterforce to vibrations, then vibration attenuation is achieved, but device complexity and cost increase
Solution Approach 1:
The electric motor serves itself by using its own torque control capability to generate counteracting torque for vibration attenuation. The control system processes vibration measurements and adjusts the motor torque to produce the necessary counterforce, eliminating the need for separate actuators. This self-service approach reduces device complexity while maintaining effective vibration control.
Solution Approach 2:
The electric motor performs multiple functions: it provides the primary propulsion function and simultaneously serves as the actuator for vibration attenuation. By utilizing the motor's existing torque control capabilities for dual purposes, the system eliminates the need for dedicated vibration control actuators, thereby reducing overall system complexity and cost.
2Object-affected harmful factors
If multiple separate actuators are arranged to act on the propulsion unit, then vibration control coverage is improved, but ease of operation and maintenance deteriorate
Solution Approach 1:
The electric motor's control system automatically processes vibration measurements and generates appropriate torque adjustments without requiring manual intervention or coordination of multiple actuators. This single integrated control approach simplifies operation while maintaining comprehensive vibration control effectiveness across all directions.
3Object-affected harmful factors
If external actuators are used for vibration control, then counterforce production is achieved, but manufacturing precision and alignment requirements increase
Solution Approach 1:
The electric motor, being an integrated component of the propulsion unit, inherently maintains precise alignment with the propulsion shaft. By utilizing the motor's own torque control for vibration attenuation, the system eliminates the need for separate actuators that would require complex alignment and mounting precision, thereby reducing manufacturing and installation complexity.
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 and attenuates vibrations by producing counteracting thrusts and bending moments within the propulsion unit, effectively managing major natural vibrations in longitudinal, transverse, and rotational directions, enhancing the overall stability and performance of the vessel.
Implementation Method 1
The vibrations of the propulsion unit may be measured with at least one measuring device
Implementation Method 2
The first auxiliary torque control signal produces an action in an opposite direction to the measured vibrations of the propulsion unit
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The propulsion unit (20) comprises a frame construction (21) having an upper portion (22) forming a support arm protruding from a hull (11) of the vessel (10) and a lower portion (23) forming a longitudinal compartment provided with a propeller shaft (41) having at least one propeller (55) attached thereto, and a first electric motor (30) driving the propeller shaft (41). The method comprises measuring vibrations of the propulsion unit (20) with at least one measuring device (300), forming a first auxiliary torque control signal (Tq11) based on the measured vibration signal, adding the first auxiliary torque control signal (Tq11) to a first torque control signal (Tq1) produced by a first torque controller (230) of the first electric motor (30). The first auxiliary torque signal (Tq11) acts against the measured vibrations.