Marine Propulsion Controller Swaying Mode Thrust Balance
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Solution Overview
Problem
Conventional systems for controlling marine propulsion devices in watercrafts face challenges in achieving balanced thrust when switching between forward and rearward moving states, leading to undesirable movement towards the front side instead of a straight sideways direction due to differences in transient characteristics between forward and rearward thrusts.
Innovation Solution
A system comprising a first and second marine propulsion device, each with a shift mechanism switchable between forward and rearward moving states, and a controller that controls the propulsion devices in a swaying or bow turning mode by initially setting one to the rearward moving state and then switching to the forward moving state after a delay, thereby reducing the difference in thrust magnitudes and ensuring accurate movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If both marine propulsion devices are switched to forward and rearward moving states simultaneously, then the watercraft can respond quickly to control inputs, but the thrusts become unbalanced causing the watercraft to move towards the front side instead of sideways
Solution Approach 1:
The controller switches one propulsion device to the rearward moving state before switching the other to the forward moving state. This preliminary action ensures that the rearward thrust is established first, compensating for the slower transient response of rearward moving thrust, thereby achieving balanced net thrust and accurate sideways movement without frontward deviation
Solution Approach 2:
The controller applies a counteracting delay to the forward moving state switch. By delaying the switch to forward moving state relative to the rearward moving state switch, the system pre-compensates for the inherent transient characteristic difference, preventing the unbalanced thrust condition that would cause frontward movement
2Productivity
If the shift mechanism is switched quickly between forward and rearward states, then operational efficiency is improved, but thrust balance is compromised leading to undesirable watercraft movement
Solution Approach 1:
The controller implements preliminary switching of one propulsion device to the rearward moving state before switching the other to forward moving state. This staged approach maintains operational efficiency by minimizing total switch time while ensuring thrust balance through proper sequencing, preventing watercraft deviation during mode transitions
Data Source
AI summary
In a swaying mode of a watercraft, a controller sets either of a first shift mechanism and a second shift mechanism to a forward moving state and sets the other of the first and second shift mechanisms to a rearward moving state, while controlling a rudder angle of a first marine propulsion device and a rudder angle of a second marine propulsion device such that a net thrust of a thrust generated by the first marine propulsion device and a thrust generated by the second marine propulsion device is oriented in a sideways direction. When setting the first shift mechanism to the forward moving state and setting the second shift mechanism to the rearward moving state in the swaying mode, the controller switches the second shift mechanism to the rearward moving state and then switches the first shift mechanism to the forward moving state after a delay at the start of the swaying mode.