Hoist Drive Control for Rope Elongation Compensation
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Solution Overview
Problem
Hoisting machines in mining face issues with rope expansion and contraction during loading and unloading, leading to vibrations, misalignment of the conveying vessel, and reduced service life due to the mechanical stress and inefficiencies in speed and torque control.
Innovation Solution
The method involves continuously adapting the rotation angle of the cable carrier based on a predetermined rotation angle profile, keeping the drive active during loading and unloading to compensate for rope length changes, ensuring the conveying vessel remains in the optimal position without applying a mechanical braking device, thus minimizing wear and cycle duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the hoisting machine operates with a mechanical braking device for stopping during loading and unloading, then the conveying vessel can be positioned accurately, but the braking process causes dead time and wear on the braking elements
Solution Approach 1:
The patent replaces the mechanical braking device with an electrical brake control that keeps the drive switched on during loading and unloading. The drive's electromagnetic brake is used instead of a separate mechanical braking system, eliminating dead time and wear while maintaining positioning accuracy through continuous drive control.
Solution Approach 2:
The drive remains switched on continuously during the loading and unloading process, eliminating the stop-start cycle caused by mechanical braking. This continuous operation maintains the conveying vessel in the optimal position without dead time, as the drive can smoothly adjust speed and position throughout the entire loading/unloading duration.
2Productivity
If the hoisting rope is stretched quickly during loading to minimize loading time, then productivity increases, but the rope expands up to 1.5 m causing vertical vibrations and misalignment of the conveying vessel
Solution Approach 1:
The patent uses feedback control through the drive's speed and position sensors to continuously monitor the conveying vessel's position and the hoisting rope's elongation. The control device adjusts the drive's output in real-time to compensate for rope expansion, maintaining the conveying vessel in the optimal loading position while accommodating rapid loading speeds.
Solution Approach 2:
The system dynamically adjusts the drive's speed and torque during loading to manage rope elongation. By continuously adapting the rotation angle of the cable carrier based on a predetermined rotation angle profile, the system allows rapid rope stretching for productivity while using active control to prevent excessive vibrations and maintain positioning accuracy.
3Manufacturing precision
If the hoisting machine uses a predetermined rotation angle profile for the cable carrier, then the conveying vessel remains in the optimal position during loading and unloading, but the control system complexity increases
Solution Approach 1:
The patent uses a predetermined rotation angle profile that is calculated and stored in advance for the cable carrier's operation. This pre-calculated profile accounts for rope elongation characteristics and loading/unloading cycles, allowing the control system to simply follow the stored profile rather than performing complex real-time calculations, thus maintaining positioning accuracy while limiting control system complexity.
4Reliability
If mechanical braking devices are used to stop the hoisting machine during loading and unloading, then the conveying vessel can be held in position, but the braking elements experience increased wear and service life is reduced
Solution Approach 1:
The patent eliminates the separate mechanical braking device and uses the drive's electromagnetic brake instead. The drive remains switched on during loading and unloading, using electrical control to hold the conveying vessel in position without mechanical contact braking, thereby eliminating wear on braking elements while maintaining reliable position holding capability.
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 prevents vertical oscillations, maintains the conveying vessel's optimal position, reduces mechanical stress, and enhances the efficiency and productivity of the hoisting machine by avoiding dead times associated with braking, resulting in lower shock loads and precise control.
Implementation Method 1
during the loading of a hoisting vessel, the hoisting rope sometimes expands up to 1.5 m or more due to the increase in weight of the hoisting vessel
Implementation Method 2
the drive remains switched on and, to compensate for a change in the conveying rope length, a rotation angle of the cable carrier is continuously adapted
Data Source
Figure 1
AI summary
The invention relates to a method for actuating a hoist (2), in particular for a shaft hoisting system, comprising a drive (4) having an associated control device (6), a cable carrier (8), at least one hoisting cable (10), and at least one hoist container (12, 14) for the vertical transport of transported material. The hoisting cable (10) elongates during loading of the hoist container (12, 14) due to the weight increase of the hoist container (12, 14). During unloading of the hoist container (12, 14), the hoisting cable (10) contracts again. In order to ensure height compensation during loading and unloading of the at least one hoist container, the drive (4) remains activated during loading or unloading and, to compensate for a change to the hoisting cable length, a rotation angle (α) of the cable carrier (8) is continually adjusted based on a predetermined rotation angle progression.