Twin Watercraft Propulsion Control for Steering Torque Interference
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Solution Overview
Problem
Existing watercraft propulsion systems face challenges in controlling the steering states of multiple propulsion devices, leading to excessive steering load torque due to water jets generated by adjacent propulsion devices, which hinders proper steering angle application and watercraft behavior.
Innovation Solution
A watercraft propulsion system with a controller that detects potential load torque increase conditions and performs propulsive force restricting control to adjust the propulsive forces of adjacent propulsion devices, ensuring they are steered to their target angles without excessive torque, using a bow turning mode that steers devices in a V-shaped orientation or tangentially around the hull's turning center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the watercraft propulsion system uses multiple adjacent propulsion devices to enable diverse watercraft behaviors, then the versatility of watercraft maneuvering is improved, but the steering load torque increases excessively due to water jet interference
Solution Approach 1:
The controller performs preliminary assessment of steering load torque before actuating the propulsion devices. By evaluating the anticipated steering load torque based on the planned watercraft behavior and current propulsion device states, the system can prepare appropriate control strategies in advance, preventing excessive torque from developing during maneuvering operations
Solution Approach 2:
The controller continuously monitors the actual steering load torque during propulsion device operation and adjusts control commands based on this feedback. When the steering load torque approaches or exceeds predetermined thresholds, the controller modifies propulsion device commands to reduce torque, creating a closed-loop control system that maintains steering loads within acceptable ranges while achieving desired watercraft behaviors
2Manufacturing precision
If the propulsion devices are steered to target angles to achieve precise watercraft behavior control, then the maneuvering precision is improved, but the steering load torque becomes excessively high
Solution Approach 1:
The controller applies partial steering action by limiting the steering angle commands to values that achieve sufficient watercraft behavior control without pushing the propulsion devices to extreme steering angles. By using only the necessary portion of the available steering range, the system maintains adequate maneuvering precision while avoiding the excessive steering load torque that would result from aggressive or maximum-angle steering commands
Solution Approach 2:
The controller dynamically adjusts steering-related parameters such as steering angle targets and steering speed based on the current operational context. By changing these parameters in response to watercraft state and environmental conditions, the system maintains precise control authority while adapting to conditions that would otherwise generate excessive steering load torque
3Productivity
If the propulsive forces of adjacent propulsion devices are increased to improve watercraft response, then the productivity of watercraft maneuvering is improved, but the steering load torque increases due to water jet generation
Solution Approach 1:
The controller assesses the relationship between propulsive force commands and anticipated steering load torque before executing maneuvering commands. By evaluating the expected torque impact of planned propulsive force increases, the system can authorize higher productivity maneuvers only when steering load conditions permit, or prepare compensatory control actions in advance
Solution Approach 2:
The controller monitors steering load torque in real-time and uses this feedback to dynamically adjust propulsive force commands. When steering load torque increases due to water jet interference, the controller reduces propulsive force commands to maintain acceptable torque levels, creating a feedback-controlled balance between maneuvering productivity and steering system protection
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
The system effectively prevents excessive steering load torque by adjusting propulsive forces, allowing precise control of steering angles and maintaining proper watercraft behavior, even when propulsion devices are operated differently from conventional methods.
Implementation Method 1
a water jet generated by the first propulsion device
Data Source
AI summary
A watercraft propulsion system includes a first propulsion device attachable to a hull, a second propulsion device attachable to the hull adjacent to the first propulsion device, a first steering device to steer the first propulsion device, a second steering device to steer the second propulsion device, and a controller configured or programmed to control the first propulsion device, the second propulsion device, the first steering device, and the second steering device. The controller is configured or programmed to determine whether or not a predetermined load torque increase condition is satisfied in which a steering load torque of the second propulsion device is likely to be increased by a water jet generated by the first propulsion device, and to perform a propulsive force restricting control to restrict the propulsive forces of the first propulsion device and the second propulsion device if the predetermined load torque increase condition is satisfied.