Hybrid Watercraft Propulsion Force Matching Control
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Solution Overview
Problem
Existing watercraft propulsion systems face challenges in achieving balanced hull behavior when using multiple propulsion devices with different propulsive force increasing characteristics, leading to uneven force distribution and potential bow turning during initial movement.
Innovation Solution
A watercraft propulsion system with an engine propulsion device and an electric propulsion device, each with propellers on non-coaxial axes, and a controller that performs propulsive force matching control to synchronize the increasing characteristics of both devices, including delay and filtering processes to ensure balanced force generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple propulsion devices with different propulsive force increasing characteristics are used, then the propulsion system can provide both engine and electric propulsion capabilities, but the hull behavior becomes unbalanced during initial movement and bow turning occurs
Solution Approach 1:
The controller performs preliminary action by delaying the start of the electric propulsion device until after the engine propulsion device has generated a predetermined propulsive force. This ensures that the engine propulsion device establishes initial hull movement before the electric propulsion device activates, preventing bow turning and maintaining hull behavior stability during the transition phase.
2Speed
If the electric propulsion device starts immediately with full power, then rapid acceleration is achieved, but the propulsive force distribution becomes uneven and causes bow turning
Solution Approach 1:
The controller implements preliminary action by first requiring the engine propulsion device to generate a predetermined propulsive force before allowing the electric propulsion device to start. This sequential activation pattern ensures that the hull is already in a stable movement state from the engine propulsion before the electric propulsion engages, preventing bow turning while still enabling rapid acceleration when both devices operate together.
3Power
If propulsive forces from multiple devices are combined without coordination, then total propulsion power is maximized, but the increasing characteristics of propulsive forces differ causing uneven force distribution
Solution Approach 1:
The controller implements feedback control by continuously monitoring the propulsive force from the engine propulsion device and using this information to determine when to activate the electric propulsion device. The controller delays electric propulsion activation until the engine propulsion reaches a predetermined force level, ensuring coordinated and uniform propulsive force distribution while still allowing both devices to operate at full power when needed.
Data Source
AI summary
A watercraft propulsion system includes an engine propulsion device attachable to a hull and including a propeller rotatable about a first propeller axis, an electric propulsion device attachable to the hull and including a propeller rotatable about a second propeller axis different from the first propeller axis, and a controller configured or programmed to control the engine propulsion device and the electric propulsion device. The controller is configured or programmed to perform a propulsive force matching control to match a propulsive force increasing characteristic of the electric propulsion device with a propulsive force increasing characteristic of the engine propulsion device when a command is inputted to simultaneously generate propulsive forces from the engine propulsion device and the electric propulsion device.