Rock Drilling Rig Stress Wave Momentum Feedback Control

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Solution Overview

Problem

Existing rock drilling systems face challenges in accurately measuring and controlling stress wave energy reflected from the rock, leading to inefficient drilling due to loss of sign information and inability to adapt to varying drilling conditions.

Innovation Solution

Measuring the momentum of the stress wave reflected from the rock using displacement data to adjust the operation of the impact and feed devices, maintaining information on whether the reflected stress wave represents tensile or compressive stress, allowing for real-time adjustment of drilling conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the energy of the stress wave reflected from the rock is measured to control drilling, then the drilling efficiency can be improved, but the sign information of the reflected stress wave is lost making accurate measurement difficult

Engineering Contradiction:
Improvedrilling efficiencyVSAvoidsign information of reflected stress wave
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent replaces the conventional energy-based measurement system with a momentum-based measurement system. By measuring the momentum of the reflected stress wave instead of its energy, the system maintains the sign information that indicates whether the wave is compressive or tensile. This substitution of the measurement parameter (from energy to momentum) resolves the information loss problem while preserving the ability to control drilling efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from stress wave energy to stress wave momentum. This parameter change allows the system to retain sign information about the reflected stress wave, enabling distinction between compressive and tensile waves. The momentum parameter encompasses both magnitude and direction information, thereby solving the information loss issue while maintaining drilling control capability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the amplitude of the stress wave is increased to break hard rock, then the drilling penetration improves, but the equipment strain increases

Engineering Contradiction:
Improvedrilling penetrationVSAvoidequipment strain
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback control system that measures the momentum of the reflected stress wave and uses this information to adjust the impact device parameters in real-time. By monitoring the momentum of reflected waves, the system can detect when equipment strain becomes excessive and automatically adjust the stress wave amplitude to optimal levels, thereby maintaining drilling penetration while preventing harmful equipment strain.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent makes the stress wave generation dynamic by continuously adjusting the impact device parameters based on real-time measurements of reflected stress wave momentum. This dynamic adjustment allows the system to optimize the amplitude of stress waves for different rock conditions, increasing amplitude when needed for hard rock penetration and reducing it when equipment strain becomes problematic, thus resolving the contradiction between penetration and equipment protection.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the stress wave duration is extended to improve rock breaking, then the drilling efficiency increases, but the reflected energy increases causing equipment strain

Engineering Contradiction:
Improvedrilling efficiencyVSAvoidreflected stress wave energy
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent uses feedback control by measuring the momentum of reflected stress waves and adjusting the impact device parameters accordingly. This feedback mechanism allows the system to optimize stress wave duration by detecting when reflected energy becomes excessive and automatically reducing the duration parameter, thereby maintaining drilling efficiency while minimizing equipment strain from reflected energy.

Inventive Principle:
Principle #23Feedback

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 enables precise control of the drilling process, reducing unnecessary strain on equipment and improving drilling efficiency by distinguishing between different rock types and conditions, thereby optimizing drilling performance.

Implementation Method 1

the impact device being arranged to cause a stress wave to the tool and the tool being arranged to deliver the stress wave caused by the impact device as a compressive stress wave to the drill bit and from there further to the rock to be drilled

Methodology Applied
Scientific EffectStress wave: Shock Wave

Implementation Method 2

during drilling at least some of the compressive stress wave caused to the tool by the impact device is reflected as a stress wave from the rock to be drilled back to the tool

Methodology Applied
Scientific EffectWave reflection: Reflection

Implementation Method 3

measuring means arranged to measure a displacement of the tool to the drilling direction or towards the drilling machine and the control and data processing unit being arranged to determine on the basis of the displacement of the tool the momentum of the stress wave reflected from the rock to be drilled to the tool

Methodology Applied
Scientific EffectDisplacement measurement: Displacement

Data Source

PatentEP2328723B1Method and arrangement in rock drilling rig
Publication Date: 2018.05.30 SANDVIK MINING & CONSTR OY
  • EP2328723B1 patent drawingFigure 1~2
  • EP2328723B1 patent drawingFigure 3~5
  • EP2328723B1 patent drawingFigure 6~7

AI summary

A rock drilling rig (1) is provided with a rock drilling machine (6) comprising an impact device (4), a feed device (9) and a tool (7) with a drill bit (8) at the end thereof for breaking rock. The impact device is arranged to cause a stress wave to the tool and from there further to the rock to be drilled. During drilling at least some of the compressive stress wave (si) caused to the tool is reflected as a stress wave (sr) from the rock back to the tool. The method comprises determining a momentum ( Pr ) of the stress wave ( sr) reflected from the rock to the tool and adjusting the operation of the impact device and/or that of the feed device on the basis of the momentum.