Single Rear Marine Drive With Bow Thruster for Precise Sway
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Solution Overview
Problem
Existing marine vessel control systems struggle to provide precise control over lateral movement and sway movement, particularly with single rear propulsion devices that lack thrust vector cancellation and have limited steering angle ranges.
Innovation Solution
A propulsion system with a single steerable rear marine drive and a lateral marine drive, controlled by a user input device, automatically alternates between forward and reverse thrusts to effectuate sway movement, coordinating thrusts to approximate the commanded lateral motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single rear marine drive is used to reduce device complexity, then the number of propulsion devices is reduced, but the ability to provide precise lateral movement and sway control deteriorates
Solution Approach 1:
The control system implements periodic alternation between forward and reverse thrust cycles of the single rear marine drive. By rapidly switching between forward and reverse thrust in a periodic manner, the system generates an average lateral force that approximates the commanded sway movement, enabling precise lateral control without requiring multiple propulsion devices
Solution Approach 2:
The system dynamically changes the steering angle and thrust magnitude parameters of the single rear marine drive during operation. By adjusting these parameters in real-time based on the commanded sway movement and current vessel state, the system optimizes the thrust vector to achieve precise lateral control
2Stability of the object's composition
If the steering angle range is limited to improve stability, then the vessel maintains better directional stability, but the range of achievable sway movements deteriorates
Solution Approach 1:
The system uses periodic alternation between forward and reverse thrust with steering angles at or near the maximum stable limit. By rapidly switching between these extreme but stable positions, the system achieves a wider effective sway movement range while maintaining vessel stability during each thrust phase
Solution Approach 2:
The control system dynamically adjusts the thrust cycle duration and steering angle based on the commanded sway movement magnitude. For larger sway commands, the system uses shorter thrust cycles with maximum steering angles, while for smaller commands, it uses longer cycles with reduced angles, optimizing both stability and adaptability
3Adaptability or versatility
If forward and reverse thrusts are alternated rapidly to achieve sway movement, then lateral control capability is improved, but the complexity of the control system deteriorates
Solution Approach 1:
The control system uses feedback from sensors measuring the vessel's actual position, velocity, and orientation to continuously adjust the thrust cycle parameters. This closed-loop control enables the simple single-drive system to achieve complex lateral movement patterns by reacting to real-time vessel state
Solution Approach 2:
The control system automatically determines the optimal thrust cycle parameters based on the commanded sway movement and current vessel state without requiring complex mechanical linkages or additional propulsion devices. The single rear drive serves multiple functions through intelligent control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise lateral movement and sway control of marine vessels by canceling uncommanded forward and backward components, enhancing maneuverability and control accuracy.
Implementation Method 1
a powerhead, such as an electric motor or an internal combustion engine, driving rotation of a drive shaft that is directly or indirectly connected to a propeller on a propeller shaft and that imparts rotation thereto
Implementation Method 2
Lateral marine drives may be positioned to exert lateral force on the marine vessel, such as bow thrusters
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A marine propulsion system (100) for a marine vessel (10) includes one steerable rear marine drive (21) positioned along a centerline (CL) of the marine vessel (10) and a lateral marine drive (15) positioned at a bow region (11) of the vessel (10). The rear marine drive (21) is configured to generate forward and reverse thrusts (220, 230), wherein the rear marine drive (21) is steerable about a vertical steering axis (31) to a range of steering angles, and the lateral marine drive (15) is configured to generate lateral thrust (210) on the marine vessel (10). A user input device (40) is operable by a user to provide a sway demand input commanding sway movement of the marine vessel (10), and a control system (33) is configured to automatically control steering and thrust of the one rear marine drive (21) and thrust of the lateral marine drive (15) based on the sway demand input to generate the sway movement commanded by the user.