Marine Vessel Low-Speed Propulsion Control Without Vessel-Specific Calibration
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Solution Overview
Problem
Current systems for controlling low-speed propulsion of marine vessels require labor-intensive vessel-specific calibration and maintenance of hundreds of unique configurations, leading to performance variations across a fleet due to human factors and personal preferences.
Innovation Solution
A model-based control system that correlates joystick commands with inertial velocity values, using a command model to determine desired inertial velocities and a vessel dynamics model to calculate surge, sway, and yaw commands, eliminating the need for vessel configuration-specific calibration and allowing unified control across various vessel configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vessel-specific calibration is performed manually for each configuration, then control accuracy for that specific vessel is improved, but device complexity and time required for setup increase significantly
Solution Approach 1:
The system creates a digital model (copy) of the vessel's propulsion system configuration, including propulsion device locations, thrust vector capabilities, and vessel dynamics parameters. This digital twin allows the control algorithm to simulate and calculate optimal thrust distributions without requiring physical calibration trials, thereby maintaining control accuracy while eliminating the need for repeated on-water testing for different configurations.
Solution Approach 2:
The system automatically adjusts control parameters based on the specific vessel configuration by inputting key parameters such as propulsion device locations, thrust capacities, and vessel mass properties into the control algorithm. This parameter-driven approach enables the system to adapt to different vessel configurations through software configuration rather than physical recalibration, reducing both complexity and time requirements.
2Measurement precision
If multiple unique configurations are maintained for different vessels, then control accuracy for each vessel is improved, but loss of time for maintenance and updates increases
Solution Approach 1:
The control system implements a universal algorithm that can handle multiple vessel configurations through a single unified software platform. The system accepts various input parameters describing different propulsion arrangements (azimuth pods, fixed propellers, hybrid configurations) and automatically calculates appropriate thrust distributions. This multi-functional capability eliminates the need to maintain separate calibration data for each vessel type, significantly reducing maintenance time while preserving control accuracy across the fleet.
3Adaptability or versatility
If human operators perform calibration and customization, then adaptability to specific vessel characteristics is improved, but reliability decreases due to human factors and personal preferences
Solution Approach 1:
The system enables automatic self-calibration by allowing operators to input basic vessel parameters (propulsion device locations, thrust capacities, vessel mass) and having the control algorithm automatically calculate and optimize thrust distributions. This eliminates human judgment and personal preferences from the calibration process, ensuring consistent, repeatable results across different operators and vessels while maintaining full adaptability to specific vessel configurations through the automated calculation process.
4Reliability
If extensive on-water testing is conducted for vessel personality development, then control performance is improved, but loss of time and resources increases
Solution Approach 1:
The system performs preliminary calculations and optimizations offline using the digital model of the vessel configuration. The control algorithm pre-calculates optimal thrust distributions for various operating conditions based on the input vessel parameters, creating a lookup table or stored solution set. This preliminary action eliminates the need for extensive on-water testing to develop vessel personality, as the optimal control strategies are already determined before the vessel deploys, significantly reducing testing time and resources while maintaining high control performance.
Data Source
AI summary
A method for controlling low-speed propulsion of a marine vessel powered by a marine propulsion system having a plurality of propulsion devices includes receiving a signal indicating a position of a manually operable input device movable to indicate desired vessel movement within three degrees of freedom, and associating the position of the manually operable input device with a desired inertial velocity of the marine vessel. A steering position command and an engine command are then determined for each of the plurality of propulsion devices based on the desired inertial velocity and the propulsion system is controlled accordingly. An actual velocity of the marine vessel is measured and a difference between the desired inertial velocity and the actual velocity is determined, where the difference is used as feedback in subsequent steering position command and engine command determinations.