Knuckle Boom Crane Load Moment Control Using Spatial Inclination

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Solution Overview

Problem

Existing crane systems fail to accurately determine the maximum permissible load moment due to insufficient characterization of the crane's position relative to spatial directions and planes, leading to potential instability and overload issues.

Innovation Solution

The crane system incorporates an arm system with multiple movable arms and sensors to detect various degrees of freedom and inclinations, coupled with a crane control system that calculates and adjusts the maximum permissible speed, acceleration, and lifting force based on these measurements to maintain stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If only lateral tilt of the machine frame is used to determine maximum permissible load moment, then the control system is simple, but the determination of maximum permissible load moment becomes inaccurate

Engineering Contradiction:
Improvecontrol system complexityVSAvoidmaximum permissible load moment determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The crane's spatial orientation is segmented into multiple independent measurement components: lateral tilt angle, longitudinal tilt angle, and slewing angle. Each component is measured separately by dedicated sensors, and their combined data provides comprehensive characterization of the crane's position relative to spatial directions and planes, resolving the inaccuracy of using only lateral tilt measurement

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The measurement system transitions from two-dimensional (only lateral tilt) to three-dimensional characterization by adding longitudinal tilt and slewing angle measurements. This multi-dimensional approach fully captures the crane's orientation in space, enabling accurate determination of maximum permissible load moment based on the arm system's actual position relative to all relevant spatial directions

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple sensors and measurements are added to accurately characterize crane position, then determination accuracy improves, but device complexity increases

Engineering Contradiction:
Improvecrane position characterization accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control system is designed with multi-functionality to process multiple sensor inputs (lateral tilt, longitudinal tilt, slewing angle) and perform comprehensive strength monitoring. The same control system determines both the maximum permissible load moment and monitors the arm system's strength, eliminating the need for separate dedicated systems and reducing overall device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Multiple measurement functions are merged into a unified control system that processes lateral tilt, longitudinal tilt, and slewing angle data together. The control system combines these measurements with arm system geometry data to simultaneously determine maximum permissible load moment and monitor strength, reducing the number of separate components needed

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the crane operates without considering arm system strength monitoring, then the operation is simpler, but the risk of overload and structural failure increases

Engineering Contradiction:
Improveoperation simplicityVSAvoidstructural safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control system continuously receives feedback from sensors measuring lateral tilt, longitudinal tilt, and slewing angles, as well as from sensors monitoring arm system geometry. This real-time feedback enables the control system to dynamically determine the arm system's strength and adjust operational parameters, maintaining structural safety without requiring complex manual assessments

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system automatically monitors the arm system's strength by processing sensor data and determining maximum permissible load moment without requiring external intervention. The system self-adjusts operational limits based on real-time measurements of crane position and arm system geometry, ensuring structural safety while maintaining ease of operation

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4686691A1Crane
Publication Date: 2026.02.04 PALFINGER AG
  • EP4686691A1 patent drawingFigure 1
  • EP4686691A1 patent drawingFigure 2
  • EP4686691A1 patent drawingFigure 3a

AI summary

Crane (7), in particular knuckle boom crane, with an arm system and - a pivotably mounted crane column (2) which has one degree of freedom (φ) detectable by a sensor (S2), - a knuckle boom (4) pivotably mounted on the crane column (2) which has one degree of freedom (β) detectable by a sensor (S4), wherein the crane (7) has at least one sensor (S1, S6) for detecting an inclination (n2, n4) of at least one pivot axis (a2, a4) relative to a spatial direction (H, V) and/or spatial plane, and a crane control system (6) for controlling and monitoring crane functions, wherein the crane control system (6) is configured to monitor the strength of the arm system as a function of the inclination (n2, n4) of at least one pivot axis (a2, a4) spatial plane, and of the currently detected values ​​of the degrees of freedom (β,to perform φ) of the arm system and to determine at least one reduction factor (f) and to limit a maximum permissible velocity and/or acceleration of a geometric change along at least one degree of freedom (β, φ) and/or a maximum permissible lifting force.