# Cutting Path Planning Technology of Shearer Based on Virtual Reality

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## Abstract

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## 1. Introduction

## 2. An Idea of Cutting Path Planning Technology of Shearer Based on Virtual Reality

- Based on the geometry model, movement model, and rule model of real equipment, the virtual model of the shearer operation was developed, which is completely consistent with reality.
- The Unity3D engine was used to build the model for the coal seam roof and floor (3D coal seam), and to obtain the orientation of the shearer and scraper conveyor; based on the geometry model, movement model, and rule model of real equipment, the virtual model of the shearer operation was developed, which is completely consistent with reality.
- The virtual Shearer was obtained to move and adjust the drum automatically on the 3D terrain;
- The prototype system was developed, different schemes simulated, and the simulation results processed and evaluated.

## 3. Kinematics Analysis and Cutting Path Planning Method of Real Shearer

#### 3.1. Kinematics Model of Shearer Height-Adjusting

#### 3.2. Kinematics Analysis of Shearer Height-Adjusting and Walking

#### 3.3. Automatic Height-Adjusting Strategy

- the maximum height difference for lifting given by $\u25b3{\mathrm{H}}_{max}=L\times \left(\mathrm{sin}\beta +\mathrm{sin}{\theta}_{max}\right),$
- the minimum height difference for lifting $\u25b3{\mathrm{H}}_{\mathrm{up}}=L\times \mathrm{sin}\beta +\frac{1}{2}\epsilon ,$
- the maximum height difference for lowering $\u25b3{\mathrm{H}}_{\mathrm{down}}=L\times \mathrm{sin}\beta -\frac{1}{2}\epsilon $,
- the range of height difference for no adjustment $\u25b3{\mathrm{H}}_{\mathrm{up}}>\u25b3\mathrm{H}>\u25b3{\mathrm{H}}_{\mathrm{down}}$,
- the minimum height difference for descending $\u25b3{\mathrm{H}}_{min}=L\times \left(\mathrm{sin}\beta -\mathrm{sin}{\theta}_{min}\right)$.

#### 3.4. Selection of Operation Parameters of the Shearer

^{3}; $b$ is the average daily advancement of coal mining face, m/d; $n$ is the annual working days, d; $N$ is the normal cycle operation coefficient, %, according to the technical performance of coal mining equipment, the production organization, staff quality, and other factors, generally taking 0.8; $c$ is the recovery rate of coal mining face, %; $a$ is the average number of coal mining face. It can be seen that for annual production capacity, the speed of coal-mining equipment needs to be adjusted when other conditions are fixed. With reference to the actual production experience of a coal mine, the minimum average traction speed of the shearer may be up to 3 m/min for higher production capacity.

## 4. Virtual Cutting Path Planning Method of Shearer and Design of Prototype System

#### 4.1. Key Technology for Modeling Coal Seam Roof and Floor

#### 4.2. Key Technology for Combined Operation of Shearer and Scraper Conveyor

#### 4.3. Key Technology of Virtual Cutting of Shearer

## 5. Simulation Experiment

#### 5.1. Setting of Simulation Conditions

#### 5.2. Analysis of Simulation Results

## 6. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 3.**Relationship between the direction of drum movement, running time and traction speed of the shearer: (

**a**) oblique view; (

**b**) Y–Z view.

**Figure 6.**Rules for sorting triangular vertices in roof and floor mesh: (

**a**,

**c**) connection order of triangle vertices; (

**b**) clockwise and counterclockwise connections.

**Figure 11.**Schematic diagram: (

**a**) the map of cutting points (

**b**) the effect of cutting points in Unity3D.

**Figure 12.**Simulation results: (

**a**) three-dimensional graph of cutting curve (

**b**) error of the actual cutting points and the preset points.

Judgment of Action | Before Adjustment | Specific Action | After Adjustment | |
---|---|---|---|---|

$\Delta H>\Delta {H}_{max}$ or $\Delta H<\Delta {H}_{min}$ | Too high or too low | Traction speed is reduced to a minimum, drum lifts | ||

$\Delta H<\Delta {H}_{max}$ and $\Delta H>\Delta {H}_{up}$ | Lifting | K-Q > 0.02 | Traction speed is increased, drum lifts | |Q-K| ≤ 0.02 |

Q-K > 0.02 | Traction speed is decreased, drum lifts | |||

|Q-K| ≤ 0.02 | Traction speed is decreased, drum lifts | |||

$\Delta H<\Delta {H}_{up}$ and $\Delta H>\Delta {H}_{down}$ | No adjustment | Traction speed is constant, drum is not adjusted | ||

$\Delta H<\Delta {H}_{down}$ and $\Delta H>\Delta {H}_{min}$ | Descending | K-Q > 0.02 | Traction speed is increased, drum descends | |Q-K| ≤ 0.02 |

Q-K > 0.02 | Traction speed is decreased, drum descends | |||

|Q-K| ≤ 0.02 | Traction speed is constant, drum descends |

Index | Recovery Rate (SSE) | Production Efficiency (min) | Others (Safety Degree, Labor Cost, etc.) |
---|---|---|---|

Scheme1 | 13.89 | 8 | 8 |

Scheme2 | 92.5 | 7 | 8 |

Scheme3 | 125.73 | 5.5 | 8 |

Scheme4 | 40.96 | 8.5 | 2 |

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**MDPI and ACS Style**

Li, J.; Liu, Y.; Xie, J.; Wang, X.; Ge, X.
Cutting Path Planning Technology of Shearer Based on Virtual Reality. *Appl. Sci.* **2020**, *10*, 771.
https://doi.org/10.3390/app10030771

**AMA Style**

Li J, Liu Y, Xie J, Wang X, Ge X.
Cutting Path Planning Technology of Shearer Based on Virtual Reality. *Applied Sciences*. 2020; 10(3):771.
https://doi.org/10.3390/app10030771

**Chicago/Turabian Style**

Li, Juanli, Yang Liu, Jiacheng Xie, Xuewen Wang, and Xing Ge.
2020. "Cutting Path Planning Technology of Shearer Based on Virtual Reality" *Applied Sciences* 10, no. 3: 771.
https://doi.org/10.3390/app10030771