Marine Steering Actuator with Dual-Sensor Position Calibration

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Solution Overview

Problem

Existing marine steering systems face challenges in efficiently and reliably steering marine vessels due to limitations in actuator design, particularly in handling varying loads and preventing engine collisions, which can lead to inefficiencies and potential safety issues.

Innovation Solution

The development of an electric actuator with an integrated steering control unit, featuring a stator, rotor assembly, and brake system, which includes Hall Effect sensors and a roller screw assembly, allows for precise control of the steering force and torque, reducing the risk of engine collisions through advanced control logic and redundancy in position sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional actuator design is used, then the structure is simpler, but the precision and reliability of steering control deteriorates

Engineering Contradiction:
Improvesteering precisionVSAvoidactuator structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The actuator is divided into distinct functional modules: motor assembly, roller screw assembly, brake assembly, and housing. Each module performs a specific function and can be independently manufactured and assembled, achieving high steering precision through modular design while maintaining manufacturing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The roller screw assembly is nested within the motor assembly, with the output shaft coupled to the motor shaft. The brake assembly is integrated into the housing structure. This nested arrangement achieves compact, precise steering control without proportionally increasing overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If basic position sensing is used, then the device complexity is lower, but the ability to prevent engine collisions deteriorates

Engineering Contradiction:
Improvecollision prevention reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Hall effect sensors provide continuous feedback on the angular position of the output shaft and the linear position of the housing. The control system processes this feedback to detect potential engine collision conditions and automatically adjusts steering commands to prevent collisions, achieving high reliability through intelligent control rather than mechanical complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Electronic sensing and control systems replace mechanical collision prevention mechanisms. Hall effect sensors and microcontroller-based control logic detect and prevent engine collisions through software algorithms, reducing mechanical complexity while improving reliability and adaptability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If simple load handling is implemented, then the device complexity is reduced, but the adaptability to varying loads deteriorates

Engineering Contradiction:
Improveload adaptation capabilityVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The actuator employs dynamic control through the roller screw mechanism, which converts rotational motor motion into linear housing displacement with variable force characteristics. The system adapts to varying loads through electronic control of motor torque and speed, allowing the same hardware to handle different steering forces required for various vessel sizes and operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system adjusts operational parameters such as motor voltage, current, and rotational speed based on detected load conditions. Hall effect sensor feedback enables real-time parameter modification to optimize performance across different load scenarios, achieving versatility through software-based parameter tuning rather than mechanical reconfiguration.

Inventive Principle:
Principle #35Parameter changes

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 solution enhances the precision and reliability of marine vessel steering by minimizing backlash, adapting to varying loads, and preventing engine collisions, thereby improving steering performance and safety.

Implementation Method 1

The brake system includes Hall Effect sensors

Methodology Applied
Scientific EffectHall Effect: Hall Effect

Implementation Method 2

There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP3569490B1Electric actuator for a marine vessel
Publication Date: 2024.07.03 DOMETIC MARINE CANADA INC
  • EP3569490B1 patent drawingFigure 1
  • EP3569490B1 patent drawingFigure 2
  • EP3569490B1 patent drawingFigure 3

AI summary

An actuator for imparting steering movement to a tiller of a propulsion unit of a marine vessel comprises an absolute position sensor which senses a steering position and a relative position sensor which senses a position of the motor. A steering control unit calibrates the relative position sensor based on a signal of the absolute position sensor. Calibration of the relative position sensor based on a signal of the absolute positon sensor initializes an accumulative position which accumulates a relative position as the actuator moves over time.