Tower Crane Automatic Path Control for Pendular Load Damping
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Solution Overview
Problem
Tower cranes face challenges in controlling load movements, leading to potential hazards due to pendular movements, which can be hazardous and require significant operator experience and concentration, especially in repetitive tasks.
Innovation Solution
A crane system with a control device that determines and automatically adjusts the traversing path using a traversing path determining module and automatic traversing control module, incorporating point-to-point control with an overlooping function, sway damping devices, and access to building data models for dynamic path corrections, reducing operator fatigue and pendular movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual control by operator is used, then flexibility in handling different situations is maintained, but operator fatigue and concentration requirements increase leading to potential hazards
Solution Approach 1:
The crane system performs automatic path determination and trajectory control without continuous operator intervention. The control device autonomously calculates the traversing path, determines intermediate positions, and controls driving devices to follow the optimal path, making the system self-sufficient in routine operations.
Solution Approach 2:
Manual mechanical control by the operator is replaced with an automated control system that uses processing units to determine paths and control devices to execute movements. This substitution eliminates human fatigue and concentration issues while maintaining precise control.
2Reliability
If automatic control is implemented, then operator fatigue is reduced and safety is improved, but system complexity increases
Solution Approach 1:
The control device integrates multiple functions including path determination, intermediate position calculation, trajectory optimization, and driving device control within a single integrated system. This multi-functionality reduces the need for separate specialized components.
Solution Approach 2:
The system continuously monitors the actual position of the load lifting means and compares it with the desired path, automatically adjusting the trajectory to maintain optimal performance. This closed-loop control ensures safety while managing system complexity through intelligent regulation.
3Productivity
If direct path between target points is used, then traversal time is minimized, but pendular movements and oscillations increase creating hazards
Solution Approach 1:
The control device pre-calculates intermediate positions and optimizes the trajectory before execution, anticipating and preventing oscillations before they occur. This preliminary planning allows for smooth acceleration and deceleration profiles that minimize pendular movements.
Solution Approach 2:
The system dynamically adjusts the traversing path and speed profile during operation, modifying the trajectory in real-time to maintain optimal performance while minimizing oscillations. The control adapts to the actual system state rather than following a rigid pre-programmed path.
4Reliability
If frequent path corrections are made to avoid obstacles, then collision risk is reduced, but traversal time increases and productivity decreases
Solution Approach 1:
The control device receives obstacle information in advance and pre-calculates alternative paths or adjustment points before reaching the obstacle area. This proactive approach allows for smooth detours without sudden corrections that would waste time.
Solution Approach 2:
The system maintains continuous motion along an optimized path that naturally flows around obstacles rather than stopping or making abrupt changes. The traversing path is designed to minimize interruptions and maintain productive movement throughout the journey.
Data Source
AI summary
A tower crane with a load lifting means mounted on a hoisting cable, driving devices for moving several crane elements and traversing the load lifting means, and a control device for controlling the driving devices such that the load lifting means moves along a traversing path between at least two target points. The control device has a traversing path determining module for determining a desired traversing path between the at least two target points and an automatic traversing control module for automatically traversing the load lifting means along the determined traversing path.