Vessel Thrust Vector Control for Precise Docking Maneuvers
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Solution Overview
Problem
Existing vessel governing systems with two engines at the stern face challenges in precise and rapid maneuvering, particularly during special maneuvers like transversal translation and rotation, due to inertia and delayed responses, leading to imprecise trajectories and safety concerns during docking and mooring.
Innovation Solution
A governing method and system utilizing bow-thruster and stern-thruster, combined with independently steerable engines, employs command signals to adjust propeller direction, thrust intensity, and steering angles, with an initial phase of incremental adjustments to overcome inertia, allowing precise control of vessel movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional two-engine stern propulsion systems are used, then the vessel can achieve basic forward and reverse movement, but the response time is delayed and maneuvering precision is poor due to inertia
Solution Approach 1:
The propulsion system is segmented into four independent thrust sources: two stern engines and two bow/stern thrusters. Each thruster can be independently controlled to provide immediate directional adjustment without waiting for the main engines to respond, thereby improving response speed and reducing delayed response time during maneuvering operations.
Solution Approach 2:
The bow and stern thrusters are activated in advance during the initial phase of maneuvering to counteract vessel inertia before the main engines reach full effectiveness. This preliminary action allows the vessel to begin changing direction or position immediately, rather than waiting for the heavier main propulsion system to respond.
2Measurement precision
If traditional two-engine systems are used, then the structure is simpler, but the maneuvering precision during special maneuvers like transversal translation and rotation is insufficient
Solution Approach 1:
The propulsion system is divided into four independently controllable thrusters (two main stern engines and two bow/stern thrusters), allowing precise control of each unit to achieve complex maneuvering patterns such as transversal translation and rotation. This segmentation enables independent adjustment of thrust magnitude and direction for each unit, significantly improving maneuvering precision.
Solution Approach 2:
The system varies multiple parameters including thrust intensity, steering angles, and activation sequences of different thrusters to achieve precise control during special maneuvers. By dynamically adjusting these parameters, the system can execute complex movements with high precision despite increased structural complexity.
3Measurement precision
If incremental adjustments are made to overcome inertia, then maneuvering precision improves, but the control process becomes more complex
Solution Approach 1:
During the initial phase of maneuvering, the bow and stern thrusters are activated first to counteract vessel inertia and establish the desired trajectory. This preliminary action creates a head start in position correction, allowing the main engines to subsequently make smaller incremental adjustments to maintain precision, thereby managing control complexity.
Solution Approach 2:
The control system operates in distinct phases: an initial phase where bow/stern thrusters provide frequent incremental adjustments to overcome inertia and establish trajectory, followed by a subsequent phase where main engines make coarser adjustments. This periodic switching between control modes improves trajectory precision while managing overall control complexity through structured phase transitions.
Data Source
AI summary
A method for governing a vessel having a bow-thruster, a stern-thruster respectively, and two engines includes activating the bow-thruster and/or of the stern-thruster with a predetermined number of revolutions and a predetermined rotation direction of the propeller, and simultaneously activating the engines in combination, with a predetermined number of revolutions and a predetermined setting of forward or reverse gear for each of the two engines, with one or more or settings, which are the steering angles of the engines, the gear direction and/or the neutral condition, and the number of revolutions, and which are applied in combination of only two or of all synchronized as a function of the movement of the vessel generated by the propulsion vector resulting from the sum of the individual propulsion forces acting on a center of application of the forces defined for the vessel.