Mine Hoist Resonance Control via Dynamic Speed Reduction
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Solution Overview
Problem
Mine drum hoist systems experience transversal resonance issues due to the Lebus grooves, leading to high rope amplitudes and discomfort for personnel, which are not adequately addressed by existing methods, especially when payload and speed vary.
Innovation Solution
A method to control transversal resonance by determining the current payload and hoist speed, identifying the transversal resonance position, and reducing the speed of the conveyance in a designated speed reduction zone to move the resonance point away from the transversal resonance position, thereby avoiding resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conveyance runs at full speed through the transversal resonance position, then productivity is improved, but harmful vibrations and rope amplitudes increase severely
Solution Approach 1:
The control system pre-calculates the transversal resonance position based on current payload and speed parameters before the conveyance reaches it. Speed reduction is initiated in advance when the conveyance approaches the calculated resonance position, preventing the harmful resonance from building up while maintaining optimal speed elsewhere
Solution Approach 2:
The system dynamically adjusts the hoisting speed based on real-time payload conditions and calculated resonance positions. The speed profile is continuously optimized by reducing speed only in the specific zone where resonance would occur, rather than maintaining a fixed speed reduction throughout the entire journey
2Reliability
If a pre-set distance speed reduction is implemented, then transversal resonance is controlled for constant conditions, but adaptability to varying payload and speed conditions deteriorates
Solution Approach 1:
The control system continuously receives feedback about the current payload of the conveyance and the actual hoisting speed. Based on this feedback, it recalculates the transversal resonance position in real-time and dynamically adjusts the speed reduction zone, ensuring effective resonance control adapts to any payload or speed variations
Solution Approach 2:
The system changes the operational parameters by calculating and applying different speed reduction zones based on the current payload and speed conditions. When payload or speed varies, the resonance position calculation changes accordingly, and the control system adjusts the speed profile to match the new parameters, maintaining effectiveness across varying conditions
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
This approach effectively prevents transversal resonance from occurring for any payload and speed combination, ensuring stable operation and comfort during conveyance in mine shafts.
Implementation Method 1
If the kick is repeated, i.e. excited with a frequency that corresponds to the natural or resonance frequency of the catenary the amplitude of the transversal catenary oscillations will build up to large unacceptable values
Implementation Method 2
The cross-over section pushes the rope over in a short time creating a near rectangular pulse-shaped 'kick' on the rope in a direction perpendicular to the rope axis
Data Source
Figure 1~2
Figure 3a~3b
Figure 3c~4
AI summary
The present disclosure relates to a method of controlling transversal resonance in a catenary of a mine drum hoist system (1) comprising a hoist drum (5) having Lebus grooves, a head sheave (7), a rope (9) having a catenary (9a) extending between the hoist drum (5) and the head sheave (7) and a vertical rope portion (9b), and a conveyance (11) attached to the vertical rope portion (9b). The method comprises a) determining a current payload of the conveyance (11), b) obtaining a hoist speed of the hoist drum (5), corresponding to a first speed of the conveyance (11), c) determining a transversal resonance position along the vertical rope portion (9b) at which transversal resonance is generated in the catenary (9a) when reached by the conveyance (11) with the current payload and first speed, wherein the transversal resonance position is determined based on the current payload and on the hoist speed, and d) reducing the first speed of the conveyance in a speed reduction zone which includes the transversal resonance position. This disclosure also relates to a computer program, a hoist drum control system (3), and a mine drum hoist system (1).