Watercraft Steering Control With Sensor-Failure Feedforward Backup

Solution Overview

Problem

Existing watercraft maneuvering systems fail to maintain steering functionality when the output signal of the steering angle sensor becomes abnormal, particularly in systems with a steering wheel that has no operation range limit and relies on an operation amount sensor instead of an absolute rotation angle sensor.

Innovation Solution

Incorporating an operation amount sensor to detect the operation amount of the steering operator, a steering actuator to change the steering angle, and a steering controller that switches between feedback-control and feedforward-control based on the output signals of the steering angle sensor and operation amount sensor, ensuring the steering function is maintained even when the steering angle sensor output is abnormal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feedback control is used based on steering angle sensor output, then steering precision is improved, but steering reliability deteriorates when the sensor output becomes abnormal

Engineering Contradiction:

Improvesteering angle detection precisionVSAvoidsteering function reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary detection of abnormality in the steering angle sensor output signal before it causes complete steering failure. The abnormality detection unit continuously monitors the sensor signal and switches to feedforward control in advance when abnormality is detected, preventing total loss of steering functionality.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The operation amount sensor serves as an intermediary measurement means that provides alternative feedback when the primary steering angle sensor fails. By detecting operation amount (rotation speed or acceleration), it enables continued steering control through feedforward control, acting as a backup pathway when the primary pathway is blocked.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a steering wheel with no operation range limit is used, then maneuvering versatility is improved, but the ability to set target steering angle based on absolute rotation is worsened

Engineering Contradiction:

Improvesteering operation versatilityVSAvoidtarget steering angle setting accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The control method dynamically adapts to the limitless rotation characteristic of the steering wheel. Instead of relying on absolute position sensing, the system uses dynamic operation amount detection (rotation speed or acceleration) to determine steering commands, allowing continuous rotation while maintaining control accuracy through rate-based feedback.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the measurement parameter from absolute rotation angle to operation amount (rotation speed or acceleration). This parameter transformation enables the use of limitless rotation steering wheels while maintaining precise control, as the operation amount sensor can accurately measure rotational rate regardless of total rotation count.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If feedforward control is used based on operation amount sensor, then steering reliability is improved when steering angle sensor fails, but steering precision may deteriorate compared to feedback control

Engineering Contradiction:

Improvesteering function reliabilityVSAvoidsteering angle control precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary detection of abnormality in the steering angle sensor output signal before it causes complete steering failure. The abnormality detection unit continuously monitors the sensor signal and switches to feedforward control in advance when abnormality is detected, preventing total loss of steering functionality.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The operation amount sensor serves as an intermediary measurement means that provides alternative feedback when the primary steering angle sensor fails. By detecting operation amount (rotation speed or acceleration), it enables continued steering control through feedforward control, acting as a backup pathway when the primary pathway is blocked.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12503214B2Watercraft maneuvering system and watercraft including the watercraft maneuvering system

Publication Date: 2025.12.23 YAMAHA MOTOR CO LTD

AI summary

A watercraft includes a steering operator to be operated by a user to steer a watercraft, an operation amount sensor to detect an operation amount of the steering operator, a steering device including a steering actuator to change a steering angle, a steering angle sensor to detect the steering angle, and a steering controller configured or programmed to control the steering actuator according to an output signal of the operation amount sensor and an output signal of the steering angle sensor. The steering controller is configured or programmed to monitor the output signal of the steering angle sensor for an abnormality, feedback-control the steering actuator based on the output signal of the steering angle sensor to achieve a target steering angle when the abnormality is not detected, and feedforward-control the steering actuator based on the output signal of the operation amount sensor when the abnormality is detected.