Hull Fixed-Point Hold Control Using Error Distance and Approach Speed

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Solution Overview

Problem

Conventional hull control systems require large-scale systems to maintain a hull at a fixed point, which is inefficient and resource-intensive.

Innovation Solution

A hull control device with error distance and approaching speed calculation modules sets throttle command values based on positional relationships and ship behavior, allowing for precise control without a large-scale system, incorporating modules for disturbance direction detection and control switching, and steering angle adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a conventional hull control system is used to maintain the hull at a fixed point, then the hull position stability is improved, but the device complexity and resource requirements increase

Engineering Contradiction:
Improvehull position stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control system is segmented into distinct functional modules: error distance calculating module, approaching speed calculating module, and command value setting module. Each module performs a specific calculation or control function, allowing the system to maintain hull position stability through coordinated operation of simplified, specialized components rather than a monolithic complex system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system continuously calculates error distance between target and actual position, determines approaching speed based on temporal changes in error distance, and adjusts throttle command values accordingly. This closed-loop feedback mechanism enables stable hull position maintenance through dynamic adjustment rather than static complex control architecture.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If a large-scale control system is deployed to maintain fixed-point hold, then the control precision is improved, but the resource consumption and system scale increase

Engineering Contradiction:
Improveposition measurement precisionVSAvoidsystem resources
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The command value setting module adjusts throttle command values based on calculated error distance and approaching speed parameters. By dynamically changing control parameters according to real-time positional feedback, the system achieves high position measurement precision and control accuracy without requiring additional hardware resources or system scaling.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the throttle command value is set based on error distance and approaching speed, then the control precision is improved, but the calculation complexity increases

Engineering Contradiction:
Improvecontrol precisionVSAvoidcontrol algorithm complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The error distance and approaching speed are calculated in advance before setting the throttle command value. This preliminary calculation of positional parameters enables the command value setting module to make informed control decisions with high precision without requiring complex real-time optimization algorithms during the actual control execution phase.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3792721B1Hull control device, hull controlling method, and hull control program
Publication Date: 2023.06.21 FURUNO ELECTRIC CO LTD
  • EP3792721B1 patent drawingFigure 1
  • EP3792721B1 patent drawingFigure 2
  • EP3792721B1 patent drawingFigure 3A~3B

AI summary

A hull control device (10, 10A) is provided, which includes an error distance calculating module (221), an approaching speed calculating module (222) and a command value setting module (223). The error distance calculating module (221) calculates an error distance (e, eR, eF) between a target position (Pt, Pr, Pf) of a fixed-point hold and a ship position (P). The approaching speed calculating module (222) calculates an approaching speed (-Δe, -ΔeR, -ΔeF) of a ship to the target position (Pt, Pr, Pf). The command value setting module (223) sets a throttle command value (R) according to a combination of the error distance (e, eR, eF) and the approaching speed (-Δe, -ΔeR, -ΔeF).