Watercraft Drive Control Adapting Force Position for Docking Stability
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Solution Overview
Problem
During docking maneuvers, watercrafts often deviate from a straight sideways direction due to rotating torque caused by changes in the center of rotation, which is influenced by the center of pressure as speed increases, leading to curved paths.
Innovation Solution
The control unit adapts the position at which the force from the drive arrangements acts, taking into account the speed and the influence of the center of pressure, ensuring the force is applied through a point that compensates for the shifting center of rotation, maintaining a desired course by adjusting engine speeds and steering angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the force from the drive arrangement acts through the center of gravity, then the watercraft moves in a straight sideways direction at low speeds, but at higher speeds the center of pressure shifts causing the watercraft to follow a curved path
Solution Approach 1:
The patent applies the dynamics principle by making the position where the force acts dynamic rather than fixed. The control unit continuously adapts the position based on the current speed of the watercraft and the calculated center of pressure, allowing the system to respond to changing operating conditions. This ensures that at each speed, the force acts through the correct position to maintain a straight course, resolving the contradiction between speed and course stability.
Solution Approach 2:
The patent applies parameter changes by modifying the position parameter where the force from the drive arrangement acts. Instead of keeping this position fixed at the center of gravity, the system changes this parameter dynamically based on speed and center of pressure calculations. This parameter adaptation compensates for the shifting hydrodynamic characteristics at different speeds, maintaining stable straight-line motion despite speed variations.
2Manufacturing precision
If the watercraft is propelled sideways during docking, then docking precision is improved, but rotating torque causes the watercraft to deviate from a straight path
Solution Approach 1:
The patent applies the 'blessing in disguise' principle by converting the harmful rotating torque effect into a beneficial control mechanism. Instead of trying to eliminate the center of pressure shift entirely, the system calculates this shift and deliberately adjusts the force application position to compensate for it. This transforms the potential harm (curved path deviation) into a benefit (maintained straight course) by using the predicted center of pressure position as the basis for force application.
Solution Approach 2:
The patent applies preliminary anti-action by calculating the expected center of pressure shift at a given speed and preemptively positioning the force application point to counteract the upcoming rotational torque. The control unit determines the appropriate position before the deviation occurs, based on the current speed and hydrodynamic characteristics, thereby preventing the curved path deviation rather than correcting it after it happens.
3Device complexity
If the force application position is fixed at the center of gravity, then the control system is simple, but the watercraft cannot maintain a straight course at varying speeds
Solution Approach 1:
The patent applies the self-service principle by enabling the control system to automatically calculate and adjust the force application position based on real-time speed data and pre-stored hydrodynamic characteristics. The system serves itself by using its own speed measurement and internal calculations to determine the optimal position, without requiring external intervention or complex manual adjustments. This maintains relatively simple system architecture while achieving high course control precision.
Data Source
AI summary
A method is provided for controlling a drive arrangement in a watercraft. The method includes detecting thrust and steering commands from an operating device which is connected to a control unit, and controlling the drive arrangement based on detected commands from the operating device for obtaining a desired course of travel of the watercraft, wherein a force is generated which acts towards a defined position on the watercraft. The method furthermore includes determining the speed of the watercraft and adapting the position on which the force from the drive arrangement acts as a function of at least the speed and as a function of the influence of the position of the center of pressure of the watercraft, thereby maintaining the desired course of travel. An arrangement for controlling a drive arrangement in a watercraft is also provided.