Marine Propulsion Control for Precise Deceleration at Target Position
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Solution Overview
Problem
Large marine vessels equipped with dynamic positioning control systems often fail to sufficiently decelerate and stop at target positions due to residual thrust from multiple outboard motors and large hull inertial forces, leading to potential passage through intended stopping points.
Innovation Solution
A marine vessel propulsion control system that includes a controller programmed to reduce the drive force of propulsion devices and selectively cut off or alternate the transmission of power to outboard motors based on predetermined conditions, ensuring sufficient deceleration and preventing passage through target positions by strategically shifting outboard motors to idle or reversing thrust direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine of each outboard motor is shifted to the idle state to reduce thrust, then the marine vessel is decelerated, but the marine vessel cannot decelerate sufficiently and passes through the target position due to residual thrust and large inertial force
Solution Approach 1:
The patent segments the control of multiple outboard motors into different control groups. When deceleration is required, the controller selectively shifts outboard motors in different groups to different idle states (first idle state with reduced thrust, second idle state with zero thrust) based on the vessel's distance from the target position and speed, enabling precise control over the residual thrust during deceleration
Solution Approach 2:
The patent changes the operational parameters of the outboard motors dynamically. The controller adjusts the throttle opening degree of each outboard motor based on real-time vessel speed and position data, transitioning motors between different idle states to optimize the balance between deceleration force and stopping precision
2Power
If the throttle is reduced and engine shifted to idle state to stop the marine vessel at target position, then the thrust is reduced, but the large hull inertial force causes the vessel to pass through the target position
Solution Approach 1:
The patent implements preliminary action by predicting the vessel's stopping point based on current speed, distance to target, and inertial characteristics. The controller calculates the required deceleration profile in advance and begins adjusting throttle settings before the vessel reaches the optimal deceleration zone, ensuring the vessel slows down progressively rather than abruptly
Solution Approach 2:
The controller periodically updates the throttle settings of outboard motors based on real-time feedback from position and speed sensors. This periodic adjustment allows the system to maintain optimal deceleration force while preventing overshoot of the target position
Data Source
AI summary
A marine vessel propulsion control system includes a controller to control a movement of a marine vessel and propulsion devices each including a power source and a thrust generator to generate a thrust based on a drive force of the power source. The controller controls the movement of the marine vessel to navigate according to a preset sea route including a target position. The controller reduces the drive force of the power source of each of the propulsion devices when the marine vessel reaches a deceleration start position that is spaced apart from the target position by a required deceleration distance, and, after reducing the drive force of the power source of each of the propulsion devices, cuts off transmission of the drive force from the power source to the thrust generator in at least one of the propulsion devices depending on a predetermined condition.