Ship Crane Load Control Using Inertial Sensors
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Solution Overview
Problem
Existing crane control systems on ships face uncertainties in determining the maximum permissible load due to wave movements, as they fail to accurately consider the ship's movement and its impact on load moment limitations.
Innovation Solution
A crane control system that uses inertial sensors, such as gyroscopes and acceleration sensors, to measure the ship's movement and determine the maximum permissible load by calculating the speed and acceleration of the boom tip, allowing for real-time adjustments and higher load capacities with maintained safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the maximum permissible load is determined based on significant wave height and sea state, then the load moment limiter can be simplified, but the determination becomes uncertain and less reliable
Solution Approach 1:
The patent replaces the traditional mechanical/empirical approach (using significant wave height and sea state tables) with an inertial measurement system that directly measures ship movements through accelerometers and gyroscopes. This substitution of measurement methodology eliminates the uncertainty associated with indirect sea state estimation while maintaining system simplicity.
Solution Approach 2:
The system uses the ship's own movement characteristics, measured by inertial sensors mounted on the vessel, to determine the maximum permissible load. This self-service approach eliminates the need for external sea state data or complex environmental modeling, directly addressing the reliability issue through self-measurement.
2Measurement precision
If the boom tip movement is determined from significant wave height, then the load moment limiter can be simplified, but the determination becomes difficult and inaccurate
Solution Approach 1:
The patent substitutes the indirect measurement of significant wave height with direct measurement of boom tip movement using inertial sensors. This replacement eliminates the difficulty of detecting wave height parameters and provides precise, real-time data on actual boom tip movement, resolving the measurement precision issue.
Solution Approach 2:
The inertial measurement system acts as an intermediary between the ship's movement and the load moment limiter calculation. By measuring accelerations and orientations directly and converting them to boom tip movement, the system bridges the gap between vessel motion and crane load assessment with high precision.
3Reliability
If the maximum load limit is determined without considering ship movement, then the control system can be simpler, but safety is compromised
Solution Approach 1:
The system uses the ship's own inertial measurement data to dynamically adjust the maximum permissible load, ensuring safety is maintained through self-awareness of the vessel's movement state. This self-service approach to safety assessment adds minimal complexity while significantly improving reliability.
Solution Approach 2:
The patent implements feedback by continuously measuring ship movements through inertial sensors and using this real-time data to adjust the maximum permissible load calculation. This closed-loop feedback ensures safety is dynamically maintained according to actual sea conditions, resolving the safety-reliability contradiction.
4Measurement precision
If the load moment limiter does not account for actual ship movement, then the system can be simpler to operate, but the maximum permissible load cannot be accurately determined
Solution Approach 1:
The system automatically measures and processes ship movement data through inertial sensors, eliminating the need for manual input or complex operational procedures. The self-service measurement and calculation approach maintains ease of operation while significantly improving the accuracy of maximum permissible load determination.
Solution Approach 2:
The patent replaces manual or simplified operational assumptions with automated inertial measurement and calculation systems. This substitution maintains operational simplicity while achieving accurate, real-time determination of maximum permissible load based on actual ship movement conditions.
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
This system provides a more reliable determination of the maximum lifting capacity, enabling safer and more efficient crane operations by accurately accounting for ship movements, thereby increasing load capacities while ensuring high safety standards.
Implementation Method 1
an inertial measuring system is used as the measuring unit, from whose data the movement of the boom tip of the crane can be determined
Data Source
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AI summary
The present invention relates to a crane control for a crane (3) arranged on a ship (1), with a load moment limitation which determines a maximum permissible load, wherein the load moment limitation is connected to a measuring unit (MU1, MU2) for measuring the movement of the ship and determines the maximum permissible load on the basis of data from the measuring unit.