Ship Speed Control Responsiveness During Turning Maneuvers

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Solution Overview

Problem

Existing ship control systems experience unnecessary load fluctuations on the main engine during turning, leading to increased fuel consumption due to interference between ship speed control and rudder angle control.

Innovation Solution

A ship control system that includes a main engine controller for feedback control of actual ship speed, a turning judgment unit to determine if the ship will turn, and a control change unit that reduces the responsiveness of ship speed control when turning is judged, thereby minimizing load fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the main engine torque is increased during ship speed control upon detection of rudder operation or yaw rate, then the turning speed is improved, but unnecessary load fluctuations occur on the main engine leading to increased fuel consumption

Engineering Contradiction:
Improveturning speedVSAvoidfuel consumption
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The control responsiveness lowering unit proactively reduces the responsiveness of ship speed control before or during the turning maneuver, based on the turning judgment unit's detection of rudder operation or yaw rate. This preliminary action prevents the interference between speed control and rudder control that would otherwise cause unnecessary load fluctuations and increased fuel consumption during turning.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the responsiveness of ship speed control is maintained at normal levels during turning, then the ship speed control precision is improved, but interference with rudder angle control occurs causing unnecessary load fluctuations on the main engine

Engineering Contradiction:
Improveship speed control precisionVSAvoidload fluctuations on main engine
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the responsiveness of ship speed control based on the turning state. The control responsiveness lowering unit modifies the control characteristics in real-time when turning is detected, creating a dynamic control system that adapts to different operational phases. This dynamic adjustment eliminates the harmful load fluctuations during turning while preserving adequate speed control precision.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the ship speed control and rudder angle control are both active during turning, then the ship can maintain speed control, but the two control systems interfere with each other causing unnecessary load fluctuations on the main engine

Engineering Contradiction:
Improveship speed control capabilityVSAvoidfuel consumption
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The invention applies local quality by differentiating the control responsiveness based on the operational phase. During turning maneuvers, the responsiveness of speed control is locally adjusted (lowered) specifically for the duration of the turn, while maintaining normal responsiveness during straight sailing. This localized adjustment eliminates control interference during turning without compromising overall speed control capability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4379491A1Ship control system, control method, and control program for ship control system
Publication Date: 2024.06.05 NABTESCO CORP
  • EP4379491A1 patent drawingFigure 1
  • EP4379491A1 patent drawingFigure 2
  • EP4379491A1 patent drawingFigure 3

AI summary

A ship control system (10) of one embodiment includes: a main engine controller (18) performs, when controlling the rotational frequency of a main engine (74) based on a target ship speed of a ship (1), feedback control of an actual ship speed of the ship (1) to perform ship speed control for bringing the actual ship speed closer to the target ship speed; a turning judgment unit (21) judges whether or not the ship (1) will turn; and a control change unit (22) performs, when the turning judgment unit (21) has judged that the ship (1) will turn, lowering processing for lowering the responsiveness of the ship speed control.