Lifting Winch Control Method for Emergency Stop Rope Winding
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Solution Overview
Problem
During the ascending phase of a hanging load, emergency stops in lifting winches can lead to faulty winding of the lifting rope due to abrupt stoppage, causing potential detachment and degradation, which compromises the reliability of lifting operations.
Innovation Solution
A control method that measures the mass and speed of the hanging load, compares the ascending speed with varying thresholds, and restricts the lifting speed to prevent non-recoverable faulty winding, while activating alarms for potentially recoverable issues, allowing for visual or automated checks and unwinding to recover faulty windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high lifting speed is used during ascending, then productivity is improved, but faulty winding of the lifting rope occurs due to abrupt stoppage during emergency stop
Solution Approach 1:
The control method applies preliminary anti-action by detecting the emergency stop condition and actively controlling the motor to provide a deceleration phase before complete stop. This preliminary action counteracts the abrupt stoppage that would otherwise cause the lifting rope to detach and scatter, thereby preventing the faulty winding while maintaining high productivity during normal operation
Solution Approach 2:
The invention implements dynamics by transitioning the lifting speed from a static fixed value to a dynamic value that automatically adjusts during emergency stop. The control method modifies the motor control signals to create a deceleration curve, making the stopping process adaptive and responsive to the emergency condition, thus preventing rope detachment while maintaining operational efficiency
2Loss of time
If abrupt stoppage is implemented during emergency stop, then response time is improved, but the lifting rope detaches and scatters causing faulty winding
Solution Approach 1:
The control method applies beforehand cushioning by introducing a controlled deceleration phase before the complete stop during emergency conditions. The motor control system generates reducing control signals that gradually decrease the lifting speed, cushioning the abrupt stoppage and preventing the lifting rope from detaching and scattering, thus eliminating the harmful effect while maintaining rapid emergency response
3Productivity
If lifting speed is not restricted during ascending, then productivity is improved, but non-recoverable faulty winding occurs that cannot be corrected by unwinding
Solution Approach 1:
The invention applies preliminary action by proactively controlling the motor deceleration before the emergency stop completes, preventing the lifting speed from reaching levels that would cause non-recoverable faulty winding. This preliminary speed reduction ensures that even if emergency stop occurs, the lifting rope remains properly wound on the drum, making fault recovery unnecessary and maintaining both productivity and ease of repair
Data Source
AI summary
A method for controlling lifting of a hanging load using a lifting winch integrating a drum on which a lifting rope is wound coupled to the load, includes measuring a mass parameter and a lifting speed representative of a mass and of a displacement speed of the load and supervising an emergency stop which, once activated, shuts off the lifting winch. The method also includes, during an ascending of the load, comparing the lifting speed with a low threshold and a high threshold which vary according to the mass parameter, and monitoring lifting in an optimized mode in which the lifting speed when ascending is authorized below the high threshold and forbidden above the high threshold, and if the emergency stop is activated during an ascending and while the lifting speed is higher than the low threshold then an alarm is activated.