Cooperative Bow Thruster and Outboard Motor Control

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Solution Overview

Problem

Vessel propulsion systems with bow thrusters and outboard motors exhibit different thrust characteristics, leading to challenges in achieving intended hull behavior due to the lack of consideration for these differences in existing systems.

Innovation Solution

A vessel propulsion system that includes a bow thruster and a propulsion apparatus with a cooperative control unit, which adjusts the thrust and direction of both components based on their respective states, such as thrust characteristics, temperature, and battery conditions, to assist each other and align with the operator's intentions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a bow thruster with an electric motor is used, then the vessel can achieve precise thrust control and rapid response, but the thrust cannot be maintained for a long time due to battery limitations

Engineering Contradiction:
Improvethrust response speedVSAvoidthrust duration
Core Design Contradiction:
SpeedVSDuration of action of moving object

Solution Approach 1:

The patent combines a bow thruster with an outboard motor into an integrated propulsion system where both devices work cooperatively under unified control. The bow thruster provides rapid response and precise control, while the outboard motor provides sustained thrust capability, resolving the contradiction between short-duration high-performance thrust and long-duration operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The outboard motor serves dual functions: it acts as the main propulsion device for forward movement and simultaneously serves as a supplemental thrust source when the bow thruster cannot maintain operation. This multi-functionality allows the system to maintain desired thrust characteristics across different operational durations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the bow thruster and outboard motor operate independently, then each device can function optimally, but the hull behavior deviates from the operator's intentions due to uncoordinated thrust characteristics

Engineering Contradiction:
Improvedevice performance reliabilityVSAvoidhull behavior control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control device continuously monitors the operational states of both the bow thruster and outboard motor, and adjusts their thrust outputs based on feedback signals. This closed-loop control ensures that the combined thrust from both devices produces hull behavior that matches the operator's intentions, even though the devices have different thrust characteristics.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control device dynamically adjusts the operation parameters of both the bow thruster and outboard motor based on real-time conditions. The system can flexibly allocate thrust between the two devices, optimizing their coordinated operation to achieve desired hull behavior while maintaining the reliability of each individual device.

Inventive Principle:
Principle #15Dynamics

3Power

If the bow thruster operates at maximum thrust, then rapid maneuvering is achieved, but the battery depletes quickly reducing operational duration

Engineering Contradiction:
Improvethrust powerVSAvoidoperational duration
Core Design Contradiction:
PowerVSDuration of action of moving object

Solution Approach 1:

The control device implements partial action by allocating thrust requirements between the bow thruster and outboard motor based on battery state. When battery charge is sufficient, the bow thruster can operate at higher power levels for rapid maneuvers. When battery charge is low, the system reduces bow thruster usage and relies more on the outboard motor, preventing battery depletion while maintaining operational capability.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3722201B1Vessel propulsion system and vessel
Publication Date: 2024.05.29 YAMAHA MOTOR CO LTD
  • EP3722201B1 patent drawingFigure 1
  • EP3722201B1 patent drawingFigure 2
  • EP3722201B1 patent drawingFigure 3

AI summary

A vessel propulsion system includes a bow thruster located at a bow of a hull, an outboard motor located on the hull and provided separately from the bow thruster, and a navigation controller. The navigation controller controls at least one of the bow thruster and the outboard motor in accordance with a state of at least one other of the bow thruster and the outboard motor.