Ship Docking Route Control for Parallel Berthing Alignment
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Solution Overview
Problem
Existing ship docking systems face challenges in achieving high accuracy due to the curvature of the ship's movement path under the influence of angular velocity, leading to potential collisions and reduced precision in automatic docking.
Innovation Solution
A route generation device that generates a route for the ship to dock at a berthing facility by maintaining a bearing along the facility's direction, using a series of positions and intermediate points, and changing bearing setting modes based on distance and route geometry to prevent curvature and ensure accurate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ship is controlled to make the bearing coincide with the target bearing while bringing the ship closer to the first target position, then the automatic docking can be achieved, but the movement locus curves off under the influence of angular velocity, reducing docking accuracy
Solution Approach 1:
The patent segments the docking process into distinct phases: approach control (when distance exceeds threshold) and adjustment control (when distance is within threshold). This segmentation allows different control strategies to be applied at different stages, preventing the movement locus from curving off during critical docking phases and improving overall docking accuracy
Solution Approach 2:
The patent performs preliminary actions by setting the bearing to coincide with the target bearing in advance during the approach phase, before the ship reaches the threshold distance. This preliminary bearing alignment prevents the need for large angular velocity adjustments during the final approach, thereby preventing movement locus curvature and improving docking precision
2Manufacturing precision
If the target speed is reduced as the ship comes closer to the first target position, then the ship can be controlled more precisely, but the docking process takes longer time
Solution Approach 1:
The patent implements dynamic speed adjustment where the target speed is reduced progressively as the ship approaches the target position. The control system dynamically transitions from approach control with higher speeds to adjustment control with lower speeds, optimizing the balance between docking time and positioning precision throughout the docking process
3Manufacturing precision
If the target angular velocity is reduced as the bearing comes closer to the target bearing, then the bearing alignment can be maintained more accurately, but the response time for bearing adjustments decreases
Solution Approach 1:
The patent implements dynamic angular velocity adjustment where the target angular velocity is reduced as the bearing difference decreases. During the approach phase, larger angular velocities are permitted for faster bearing acquisition, while during the final approach within the threshold distance, angular velocity is reduced to maintain precise bearing alignment, optimizing the trade-off between adjustment speed and alignment precision
Data Source
AI summary
According to the present invention, a route controller generates a route that makes a ship dock at a berthing facility. The route includes a first location and a second location (P2). The first location is a via point that is offset a prescribed distance in a direction that is orthogonal to the direction in which the berthing facility is oriented from a docking point for the ship at the berthing facility. The second location is the docking point for the ship at the berthing facility. The first location is immediately before the second location in the sequence to be realized by the ship. The route is generated such that the ship remains oriented in the direction in which the berthing facility is oriented as the ship moves from the first location to the second location.