Dual Ship-Mounted Hoisting Arm Control for Wave Heave Compensation
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Solution Overview
Problem
Existing control strategies for ship-mounted hoists face challenges in managing complex wave responses and coupled dynamic characteristics, particularly when handling large loads under continuous wave interference.
Innovation Solution
A method and system for collaborative heave compensation control of a dual ship-mounted hoisting arm system using an incremental model predictive control algorithm, which minimizes tracking error to track a reference compensation trajectory under preset constraints, thereby improving heave compensation control performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional control strategies are applied to ship-mounted hoists, then the control system is simpler to implement, but the system cannot effectively handle complex wave responses and coupled dynamic characteristics
Solution Approach 1:
The patent divides the dual ship-mounted hoisting arm system into separate subsystems (first vertical hoisting arm, second vertical hoisting arm, first horizontal hoisting arm, second horizontal hoisting arm) with individual state variables for position and velocity. This segmentation allows the complex coupled system to be modeled and controlled through coordinated regulation of each component, making the overall control problem more manageable while maintaining effectiveness under wave interference.
Solution Approach 2:
The patent implements dynamic heave compensation control by continuously adjusting the hoisting arm positions and velocities based on real-time wave conditions. The control system dynamically adapts to changing wave interference patterns, regulating the state variables (position and velocity) of each hoisting arm to maintain stable load transfer operations despite varying maritime conditions.
2Manufacturing precision
If incremental model predictive control algorithm is used to minimize tracking error, then heave compensation control performance is improved, but computational complexity increases
Solution Approach 1:
The patent uses model predictive control to predict future states of the hoisting arm system and pre-calculate optimal control actions. By minimizing the tracking error objective function in advance and considering preset constraints, the system determines the best control strategy before execution, improving tracking accuracy while managing computational complexity through efficient optimization.
Solution Approach 2:
The incremental model predictive control algorithm continuously monitors the actual positions and velocities of the hoisting arms, compares them with the reference compensation trajectories, and adjusts the control inputs to minimize tracking error. This feedback mechanism ensures high tracking accuracy by constantly correcting deviations while the incremental approach updates control actions efficiently based on previous solutions.
3Force
If dual ship-mounted hoisting arm system is used for complete transfer of very large loads, then load capacity is sufficient, but the modeling and control becomes extremely difficult
Solution Approach 1:
The patent models the dual ship-mounted hoisting arm system by segmenting it into four distinct hoisting arm subsystems, each with its own state variables (position and velocity). This segmentation transforms the extremely difficult modeling and control of the complete system into manageable subsystems that can be coordinated through a unified control framework, making the control of very large loads feasible.
Solution Approach 2:
The patent develops a universal control framework that simultaneously handles the control of multiple hoisting arms, wave compensation, and trajectory tracking through a single integrated model predictive control algorithm. This multi-functional approach consolidates what would otherwise require multiple separate control systems, reducing overall complexity while maintaining the capability to handle very large loads.
Data Source
AI summary
A method for collaborative heave compensation control of a dual ship-mounted hoisting arm system including two vertical hoisting arms and two horizontal hoisting arms is provided, in which a dynamic model of the hoisting arm system is constructed based on hoisting arm position and velocity and an attitude angle of a load of the hoisting arm system; and based on the dynamic model, an optimal control strategy is obtained according to a control objective and an optimization objective under multiple constraint conditions to control the hoisting arm action, where the control objective is to track a hoisting arm reference compensation trajectory during the heave motion, the optimization objective is to minimize a tracking error, and the constraint conditions include a hoisting arm action constraint, and a position and velocity constraint of each hoisting arm after action. A system for implementing such method is also provided.