Lifting Control Device for Mobile Crane Load Swing Suppression

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Solution Overview

Problem

Existing lifting control devices are hindered by load swing due to boom deflection, leading to delayed lifting as they wait for stabilized load data, which slows down the lifting process.

Innovation Solution

A lifting control device with a boom, winch, and load measurement section that retains the maximum load value from time series data to determine the variation in luffing angle and compensates by adjusting the boom, allowing for high-speed lifting while suppressing load swing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If lifting control is performed based on time series load data, then lifting accuracy is improved, but lifting speed deteriorates due to waiting for stabilized data

Engineering Contradiction:
Improvelifting accuracyVSAvoidlifting speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the maximum load value from the time series load data, ignoring the vibrating components. This selective extraction allows the control system to use a single stabilizing parameter (maximum load value) rather than waiting for the entire load data to stabilize, thereby improving lifting speed while maintaining accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The control section performs preliminary stabilization of the maximum load value before using it for lifting control decisions. By stabilizing this specific parameter in advance and using it proactively for control actions, the system eliminates the need to wait for complete load data stabilization, resolving the speed-accuracy contradiction

Inventive Principle:
Principle #10Preliminary action

2Productivity

If lifting is performed at high speed, then productivity is improved, but load swing increases due to boom deflection

Engineering Contradiction:
Improvelifting speedVSAvoidload swing
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback control by continuously monitoring the maximum load value and using it to adjust the luffing angle in real-time. The control section calculates the required luffing angle based on the stabilized maximum load value and actively compensates for boom deflection, suppressing load swing even during high-speed lifting

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the luffing angle parameter dynamically based on the maximum load value to compensate for boom deflection. By adjusting this parameter in response to load conditions, the system maintains positioning accuracy and suppresses load swing during high-speed operations

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3925919B1Lifting control device and mobile crane
Publication Date: 2024.01.24 TADANO LTD
  • EP3925919B1 patent drawingFigure 1~2
  • EP3925919B1 patent drawingFigure 3
  • EP3925919B1 patent drawingFigure 4

AI summary

Provided is a lifting control device that can quickly make lifting determinations while suppressing load vibration. The lifting control device D comprises: a boom 14 that is configured to be freely raised and lowered; a winch 13 to hoist and lower a suspended load via a wire rope 16; a load measurement means 22 to measure the load acting on the boom 14; and a controller 40 that controls the boom 14 and the winch 13, wherein when lifting a suspended load from the ground by winding up the winch 13, the controller 40 retains a maximum load value from a time series of load data as a variable, finds variations in the hoisting angle of the boom 14 on the basis of time variations in the maximum load value, and raises and lowers the boom 14 so as to compensate for the variation.