Outboard Motor Thrust Control for Watercraft Porpoising
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods to alleviate porpoising in watercraft during high-speed navigation, such as reducing engine rotational speed or controlling the trim tab, inevitably result in a reduction in velocity, which is undesirable.
Innovation Solution
A system and method utilizing an outboard motor with a pitch angle sensor and controller to dynamically adjust the thrust of the motor based on the watercraft's pitch angle and angular velocity, setting a target thrust to inhibit porpoising without reducing velocity, by varying the thrust to counteract the moments causing the bow's elevation and lowering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the rotational speed of the engine is reduced to alleviate porpoising, then the porpoising is alleviated, but the velocity of the watercraft is reduced
Solution Approach 1:
The invention changes the control parameter from engine rotational speed to outboard motor thrust. By controlling the thrust of the outboard motor rather than the rotational speed of the engine, the system can alleviate porpoising while maintaining watercraft velocity. The controller adjusts the thrust based on detected porpoising conditions, allowing independent optimization of stability and speed parameters.
2Stability of the object's composition
If the trim tab is lowered to control the posture of the watercraft and alleviate porpoising, then the porpoising is alleviated, but the velocity of the watercraft is reduced
Solution Approach 1:
The invention changes the control approach from mechanical trim tab adjustment to thrust-based control. Instead of modifying the trim tab position which affects hydrodynamic posture and reduces speed, the system directly controls the thrust output of the outboard motor. This parameter change allows porpoising alleviation without the speed penalty associated with trim tab manipulation.
Solution Approach 2:
The invention replaces the mechanical trim tab system with an electronic thrust control system. The controller uses detection results from sensors to electronically adjust the thrust of the outboard motor, substituting the mechanical posture control method with an electronic propulsion control method that does not compromise velocity.
Data Source
AI summary
A controller is configured or programmed to obtain at least either of a pitch angle of a watercraft and an angular velocity of the pitch angle, obtain a present thrust of an outboard motor, and set a target thrust of the outboard motor based on the present thrust of the outboard motor and at least either of the pitch angle of the watercraft and the angular velocity of the pitch angle. The controller is configured or programmed to control a drive source such that a thrust of the outboard motor becomes the target thrust.