Rudder Force Calculation via Sensor Data for Dynamic Positioning
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Solution Overview
Problem
Existing autopilot and dynamic positioning systems for watercraft often experience 'switching hysteresis,' leading to frequent and inefficient adjustments in rudder angle and propulsion, resulting in increased wear and tear and suboptimal course control due to inadequate measurement of forces acting on the rudder.
Innovation Solution
Incorporating measuring devices on the rudder to determine rudder measurement data such as bending stress and torque, which are used to calculate lift and drag forces, allowing the control device to adjust the rudder and propulsion system more precisely, thereby reducing switching hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional autopilot systems control the rudder and propulsion without direct force measurement, then the system structure remains simple, but switching hysteresis occurs leading to frequent adjustments and increased wear
Solution Approach 1:
The patent replaces direct mechanical force measurement with a computational approach. The control device calculates rudder forces by processing data from existing sensors (rudder angle sensor, propulsion force sensor) and applying hydrodynamic models. This substitution of mechanical measurement with computational mechanics achieves force awareness without adding complex mechanical measurement systems, thereby improving course control stability while maintaining relatively simple device structure.
Solution Approach 2:
The patent introduces an intermediary computational model that mediates between existing sensors and the control system. Instead of directly measuring rudder forces with complex sensors, the system uses hydrodynamic force models as intermediaries to calculate forces from measurable parameters like rudder angle and propulsion force. This intermediary approach enables reliable force-based control while avoiding the complexity of direct force measurement systems.
2Speed
If frequent rudder adjustments are made to maintain course, then course control responsiveness improves, but wear and tear on the maneuvering system increases
Solution Approach 1:
The patent implements force-based feedback control by continuously calculating rudder forces from sensor data and using this information to adjust control commands. The control device monitors the calculated rudder forces and propulsion forces, and only initiates rudder adjustments when the force differential indicates a genuine need for course correction. This feedback mechanism enables responsive course control while minimizing unnecessary adjustments, thereby extending rudder service life.
Solution Approach 2:
The patent applies dynamic control by continuously adapting rudder commands based on real-time force calculations. Instead of fixed or overly frequent adjustment schedules, the system dynamically determines when adjustments are needed based on the calculated force balance between rudder and propulsion. This dynamic approach maintains course control responsiveness while reducing wear by avoiding static, predetermined adjustment frequencies.
3Use of energy by moving object
If traditional positioning systems use only position and basic sensor data, then the control algorithm remains simple, but energy optimization is insufficient due to lack of force information
Solution Approach 1:
The patent optimizes energy usage by changing the control parameters from simple position-based commands to force-based commands. The control device calculates optimal rudder and propulsion commands by considering the calculated rudder forces and propulsion forces, enabling energy-efficient maneuvering. This parameter change from position-only control to force-informed control improves propulsion energy efficiency while the computational approach keeps the algorithm complexity manageable.
Data Source
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AI summary
In order to reduce the switching hysteresis in a dynamic positioning system (11) and/or an autopilot system (11a) for watercraft, an arrangement (12) for determining a force acting on a rudder (10) for watercraft is provided, comprising a computing unit (29), at least one measuring device (27, 28) for determining values of a physical quantity of a rudder (10), means for transmitting the determined values of the physical quantity to the computing unit (29), wherein the computing unit (29) is designed to determine the force acting on the rudder (10) on the basis of the determined values of the physical quantity.