Marine Vessel Trajectory Planning Under Environmental Uncertainty

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Solution Overview

Problem

Current trajectory planning for marine vessels in complex environments with static and dynamic obstacles and environmental disturbances often results in sub-optimal trajectories and increased collision risks due to insufficient consideration of environmental uncertainties.

Innovation Solution

A computer-implemented method that determines a feasible trajectory by estimating environmental disturbance parameters and their uncertainties, using a maneuver model to predict future states and generate trajectory data with uncertainty, and adjusts control commands through numerical optimal control or other methods to ensure collision-free navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If large generic safety margins are considered in trajectory planning, then collision avoidance is improved, but trajectory optimality deteriorates

Engineering Contradiction:
Improvecollision avoidanceVSAvoidtrajectory optimality
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent transforms fixed generic safety margins into dynamic, environment-dependent safety margins. The safety margin is calculated based on real-time environmental disturbance parameters (wind, waves, currents) and their uncertainties, allowing the trajectory to adapt its safety buffer dynamically rather than using constant oversized margins throughout the path.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The trajectory planning system transitions from static safety margins to dynamic safety margins that continuously adapt to changing environmental conditions. The safety margin varies along the trajectory and over time based on predicted environmental disturbances, enabling optimal performance in safe conditions while maintaining adequate protection when disturbances increase.

Inventive Principle:
Principle #15Dynamics

2Reliability

If environmental disturbances and uncertainties are included in trajectory planning, then trajectory safety and reliability are improved, but computational complexity increases

Engineering Contradiction:
Improvetrajectory safetyVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary estimation of environmental disturbance parameters and their uncertainties before final trajectory generation. By predicting environmental conditions and calculating safety margins in advance, the system prepares necessary safety buffers before optimizing the trajectory, reducing the computational burden during real-time trajectory generation while maintaining high reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The trajectory planning process is divided into distinct computational stages: environmental disturbance estimation, uncertainty analysis, safety margin calculation, and trajectory optimization. This segmentation allows each module to be computationally efficient and independent, reducing overall complexity while comprehensively addressing environmental factors.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If mean environmental values are used for trajectory planning, then computational simplicity is maintained, but accuracy in capturing real environmental behavior deteriorates

Engineering Contradiction:
Improvecomputational simplicityVSAvoidenvironmental behavior accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system incorporates feedback from environmental sensors that continuously measure actual wind, wave, and current conditions. This real-time feedback allows the system to update environmental disturbance parameters and their uncertainties, capturing the true dynamic behavior of the environment rather than relying on static mean values, while maintaining computational efficiency through recursive estimation methods.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4432263A1A method for determining a trajectory for a marine vessel under environmental disturbance
Publication Date: 2024.09.18 ABB (SCHWEIZ) AG
  • EP4432263A1 patent drawingFigure 1
  • EP4432263A1 patent drawingFigure 2
  • EP4432263A1 patent drawingFigure 3

AI summary

A computer-implemented method for determining a feasible trajectory for a marine vessel traveling on water, comprising: determining (S102) initial state variables for the marine vessel at the initial position including present position of the marine vessel and a present heading direction (H1) of the marine vessel in relation to the surrounding environment; acquiring (S104) position data (24) indicating positions of obstacles near the marine vessel; acquiring (S106) environmental data (27) including at least one of present wind conditions, wave characteristics, and local sea current speed and direction; estimating (S108) environmental disturbance parameters and respective uncertainties from the environmental data; predicting (S110) subsequent state variables for the marine vessel and respective uncertainties at future time steps for a prediction horizon based on a maneuver model of a marine vessel describing a motion of a marine vessel, the initial state variables, the position data, and the environmental disturbance parameters and respective uncertainties; generating (S112) feasible trajectory data (50, 66) including a trajectory uncertainty (52, 68) for the marine vessel.