Vessel Propulsion Force Envelope for Precise Thrust Allocation
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Solution Overview
Problem
Current vessel control systems operate within conservative physical limits, leading to suboptimal performance due to inaccurate and overly restrictive constraints on propulsion machine operations, which can be improved by determining feasible forces and torques for more precise and predictable control.
Innovation Solution
A method and device for determining feasible forces and torques by providing allowable motion control signals to propulsion machines, calculating vector contributions, forming a vessel operations space, and applying it to limit control operations, while considering power limitations and avoiding water flushing between propulsion machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative physical limits are used to constrain propulsion machine operations, then system reliability is improved, but vessel performance and productivity deteriorate
Solution Approach 1:
The patent transforms the conservative fixed limits into dynamic feasible limits by changing the parameters from static conservative values to dynamic values calculated based on actual vessel state, propulsion machine characteristics, and environmental conditions. This allows the control system to operate at the true physical boundaries rather than conservative estimates, improving productivity while maintaining reliability.
Solution Approach 2:
The patent implements feedback by continuously calculating feasible forces and torques based on the current vessel state and using this information to constrain the control inputs. The feasible limits are updated in real-time based on feedback from the vessel's actual performance and conditions, allowing optimal operation within physical boundaries.
2Measurement precision
If accurate feasible forces and torques are calculated, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the complex problem of determining feasible limits into manageable parts: first determining individual propulsion machine capabilities, then calculating their combined effect on vessel motion, and finally applying these as constraints. This segmentation makes the complex calculation tractable and implementable in real-time control systems.
Solution Approach 2:
The patent performs preliminary calculations of feasible forces and torques before the actual control action is taken. By pre-calculating the feasible operation space based on current conditions, the system prepares the constraints in advance, reducing the computational burden during real-time control and improving overall efficiency.
Data Source
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AI summary
A feasible force determining device provides, for each propulsion machine of a vessel, a first set of allowable control signals of a first type with values between a minimum and a maximum value, calculates, for each allowable control signal of each propulsion machine, a vector contribution of the propulsion machine to a set of feasible forces and torques being related to at least one type of motion of the vessel, adds, for each propulsion machine, each calculated vector to all vectors in the set of feasible forces and torques, forms a vessel operations space for the operation of the vessel, which vessel operations space is based on the set of feasible forces and torques and provided in at least one dimension, and applies (S210) the vessel operations space in the operation of the vessel.