Marine Propulsion Control for Lateral Course Holding
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Solution Overview
Problem
Marine vessels equipped with a joystick face challenges in maintaining a desired lateral course due to external disturbances such as tidal currents and wind, causing deviations in the front-rear direction and yaw rotation, which complicates precise maneuvering.
Innovation Solution
A marine vessel propulsion control system with multiple propulsion devices that can individually control thrust magnitude and direction, utilizing a controller to execute controls that adjust thrust to maintain the desired lateral course by compensating for deviations in the front-rear and yaw directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a control is performed to reduce the moving speed of the marine vessel in the front-rear direction when the marine vessel starts to move in the lateral direction, then the deviation in the front-rear direction is reduced, but the marine vessel still moves in the front-rear direction due to the time required for speed reduction
Solution Approach 1:
The control system performs preliminary action by reducing the moving speed in the front-rear direction before the marine vessel actually starts moving in the lateral direction. This anticipatory speed reduction ensures that when lateral movement begins, the front-rear speed is already sufficiently reduced, preventing deviation without requiring additional time during the lateral movement phase.
2Ease of operation
If the marine vessel moves in the lateral direction, then the desired lateral movement is achieved, but external disturbances cause the marine vessel to rotate in the yaw direction and move in a direction different from the desired lateral direction
Solution Approach 1:
The control system continuously monitors the actual movement direction and yaw angle of the marine vessel during lateral movement, compares it with the desired lateral direction, and provides feedback to the propulsion control. This feedback loop enables real-time corrections to counteract external disturbances and maintain the desired course.
Solution Approach 2:
The control system dynamically changes propulsion parameters (thrust magnitude and direction) in response to detected deviations. When external disturbances cause yaw rotation or directional deviation during lateral movement, the system adjusts the propulsion device parameters to compensate and restore the desired lateral course.
3Measurement precision
If multiple propulsion devices are used to individually control thrust magnitude and direction, then precise maneuvering is achieved, but the control system complexity increases
Solution Approach 1:
The control system achieves multi-functionality by using the same controller to perform multiple functions: controlling thrust magnitude, controlling thrust direction, coordinating multiple propulsion devices, and executing both speed reduction and course correction operations. This universal approach enables precise maneuvering without proportionally increasing system complexity.
Data Source
AI summary
A marine vessel includes propulsion devices, an operator to move the marine vessel in a tilting direction of the operator, and a controller to control a magnitude and a direction of a thrust generated by each of the propulsion devices to move the marine vessel in the tilting direction of the operator. When the operator is tilted toward a lateral direction, the controller executes a first control to move the marine vessel in the lateral direction, and causes each of the propulsion devices to generate a thrust to eliminate a deviation of the marine vessel in a front-rear direction from a position of the marine vessel when the operator was tilted. When the operator is tilted in the front-rear direction of the marine vessel while the marine vessel moves in the lateral direction, the controller interrupts the first control and executes a second control to cause each of the propulsion devices to generate a thrust corresponding to the tilting of the operator.