Crane Control Damping Hoist Rope Oscillations
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Solution Overview
Problem
Existing crane control systems fail to effectively manage dynamic loads caused by the movement of loads during hoisting, leading to the need for overly stable and expensive crane structures to account for these forces.
Innovation Solution
A crane control system that takes into account the oscillation dynamics based on the elasticity of the hoist rope, reducing or damping these dynamics through suitable control of the hoisting gear, allowing for a lighter crane structure or higher static loads by limiting the hosting force to a maximum permitted value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the crane structure is made more stable to take up dynamic loads, then the crane can handle movement-induced forces, but the crane becomes more expensive and heavier
Solution Approach 1:
The patent applies dynamic control by continuously monitoring the actual hoisting force and comparing it with the maximum permitted hoisting force. The control system dynamically adjusts the hoisting gear operation based on real-time feedback, enabling the crane to handle dynamic loads effectively without requiring an overly robust static structure. This dynamic approach allows the crane to respond adaptively to load movements, reducing the need for excessive structural strength.
Solution Approach 2:
The patent implements a feedback mechanism where the control system continuously receives information about the actual hoisting force from sensors and compares it with the maximum permitted value. Based on this feedback, the system automatically adjusts the hoisting gear control to prevent exceeding the force limit. This closed-loop feedback control enables the crane to manage dynamic loads efficiently without requiring a heavier structure, as the system actively regulates forces rather than relying solely on passive structural strength.
2Weight of stationary object
If the maximum hoisting force is limited to a permitted value, then the crane structure can be built lighter, but the hoisting speed and productivity may be reduced
Solution Approach 1:
The control system dynamically adjusts the hoisting operation by continuously monitoring the actual hoisting force and comparing it with the maximum permitted value. When the force approaches the limit, the system automatically reduces the hoisting speed. This dynamic speed adjustment allows the crane to maintain higher average speeds during normal operation while preventing force limits from being exceeded, thus preserving productivity without compromising structural safety.
Solution Approach 2:
The patent changes the operational parameters of the hoisting gear by adjusting the drive speed based on the actual hoisting force. The control system modifies the speed parameter in real-time according to the load conditions and force measurements. This parameter adaptation enables the crane to optimize its performance by operating at higher speeds when forces are low and reducing speed only when necessary to maintain force within permitted limits, thereby balancing structural requirements with productivity demands.
3Ease of operation
If freehand control of hoisting gear speed is used, then the operator has full control flexibility, but substantial dynamic loads arise that require expensive stable construction
Solution Approach 1:
The patent implements feedback control where the actual hoisting force is continuously measured and fed back to the control system. This feedback enables the system to automatically adjust the hoisting gear speed to prevent excessive dynamic loads, while the operator retains control through the hand lever. The feedback mechanism acts as an intelligent assistant that guides the operator's inputs to maintain forces within safe limits, thus preserving operational flexibility without requiring excessive structural strength to handle uncontrolled dynamic loads.
Solution Approach 2:
The control system acts as an intermediary between the operator's hand lever inputs and the hoisting gear drive. It processes the operator's control signals and automatically modifies them based on the actual hoisting force measurements to prevent excessive dynamic loads. This intermediary function maintains the operator's control flexibility while introducing intelligent force management, reducing the structural strength requirements without compromising ease of operation.
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
The system reduces dynamic loads on the rope and crane structure, enabling the use of lighter crane designs or increased static loads while preventing overshoots and natural oscillations, thereby enhancing operational efficiency and reducing structural strain.
Implementation Method 1
takes into account the oscillation dynamics based on the elasticity of the hoist rope
Implementation Method 2
oscillation dynamics of the system of rope and load
Implementation Method 3
reduces or damps them by a suitable control of the hoisting gear
Data Source
AI summary
The present invention relates to a crane control for the control of a hoisting gear of a crane which takes account of oscillation dynamics based on the elasticity of the hoist rope on the control of the hoisting gear and reduces them by a suitable control of the hoisting gear.