Ship Heading Overshoot Suppression via Rudder Angle Offset

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Solution Overview

Problem

Conventional automatic ship steering systems using differential preceding type Proportional-Integral-Derivative (PID) control struggle to effectively suppress the overshoot of a heading during ship turning.

Innovation Solution

A ship control device equipped with processing circuitry that measures the overshoot amount of the heading during turning and calculates a rudder angle offset amount to correct the command rudder angle, thereby suppressing overshoot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional differential preceding type PID control is used, then the control system maintains basic stability, but the overshoot of heading during turning cannot be effectively suppressed

Engineering Contradiction:

Improveheading stabilityVSAvoidovershoot suppression performance

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements feedback by measuring the actual overshoot amount during turning and using it to calculate a correction value (rudder angle offset amount). This measured feedback is then applied to adjust the command rudder angle, creating a closed-loop control system that actively suppresses overshoot based on actual system behavior.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the control parameter by introducing a rudder angle offset amount that is calculated based on the measured overshoot. This offset is added to the command rudder angle, effectively modifying the control parameter dynamically to suppress overshoot while maintaining the basic PID control structure.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If rudder angle offset is applied to suppress overshoot, then heading accuracy improves, but ship behavior may become unstable when overshoot is within normal range

Engineering Contradiction:

Improveheading accuracyVSAvoidship behavior stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary anti-action by calculating the rudder angle offset based on the measured overshoot amount and applying it in advance to the command rudder angle. This preemptive correction counteracts the tendency to overshoot before it occurs, improving heading accuracy while maintaining stability through proportional correction.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If conventional PID control is used, then the control system remains simple, but it cannot accurately correct command rudder angle for overshoot

Engineering Contradiction:

Improvecontrol system complexityVSAvoidrudder angle correction accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by measuring the overshoot amount during turning and calculating the appropriate rudder angle offset in advance. This pre-calculated correction is then applied to the command rudder angle, enabling accurate overshoot suppression without requiring complex real-time computation during critical moments.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250153819A1Ship control device, ship control method, ship control system, and computer readable medium

Publication Date: 2025.05.15 FURUNO ELECTRIC CO LTD

AI summary

The object of the present invention is to effectively suppress an overshoot of a heading during turning. A ship control device is provided with processing circuitry. The processing circuitry measure an overshoot amount of a heading of the ship during turning based on an excessive turning amount of the heading with respect to a setting direction of the ship and calculates a rudder angle offset amount based on the overshoot amount.