# Design and Application of Simulating Cutting Experiment System for Drum Shearer
## 6 Simulated Cutting Experiment  
The laboratory had produced a longwall face with simulated coal with a length \(\times\) width \(\times\) height of 700 mm \(\times\) 200 mm \(\times\) 500 mm according to the experimental plan. The establishment of a simulated cutting experiment system is shown in Figure 9.  
When cutting, the cutting motor uses a 30 Hz input controlled by a frequency converter, and the forward speed of the simulated coal shearer at 0.5 m per minute, as shown in Figures 9 and 10. Shearer performance and system status data during cutting can be accurately acquired through measuring equipment, such as sound sensors and vibration sensors. For example, vibration signals have been used to interpret cutting conditions. The hardware of the vibration signal acquisition system is listed in Table 7.  
Figure 10: Cutting effect diagram. Figure 9: Shearer simulation cutting test system. When the shearer is cutting, the cutting load generated by the drum when cutting coal walls with various hardness is different. Therefore, it produces different cutting vibration signals. In addition, when the equipment is running, the hydraulic pump station and the cutting motor will produce vibration information [24,25]. Thus, to better collect the vibration signal generated by shearer cutting, the vibration sensor is installed at the end cover of the shaft connected with the drum, as indicated in Figure 11.  
According to the experimental plans 9, 13, and 18, the study had poured three simulated longwall coal faces and carried out cutting experiments. Meanwhile, it set a no-load cutting mode as the control group. Therefore, the test established four cutting modes, which were denoted as C1, C2, C3, and C4. The various cutting methods correspond, as shown in Table 8.  
When cutting, set the signal sampling frequency of the vibration signal at 48 KHz, and the sampling time at 0.1 s. It obtains vibration signals of four cutting modes, as shown in Figure 12. \begin{table}
\begin{tabular}{c c} \hline \hline
**Hardware** & **Model** \\ \hline Vibration sensor & LC0109 \\ Data acquisition card & NI PCIe\(-\)6323 \\ Terminal plate & CB\(-\)68 LP \\ \hline \hline \end{tabular}
\end{table} 
Table 7: List of vibration signal acquisition system. Figure 11: Installation diagram of the vibration sensor. \begin{table}
\begin{tabular}{c c} \hline \hline
**Cutting Mode** & **Cutting Medium** \\ \hline C1 & No-load \\ C2 & Experimental plan 9 \\ C3 & Experimental plan 13 \\ C4 & Experimental plan 18 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: The corresponding situation of cutting mode. Figure 12 illustrates that the amplitude of the vibration signal in the C1 no-load cutting mode is relatively minimal. With the increase of cutting medium strength, the vibration signal amplitude of C2, C3, and C4 cutting modes increases gradually. The cutting drum has impact, collision, and friction on the simulated coal wall during operation. There are periodic shock components in the collected cutting vibration signal waveform. It analyzes the vibration signals of the above four cutting modes in the frequency domain and obtains the spectrum diagram of the vibration signal drawn in Figure 13.  
Figure 12: The waveform of cutting vibration signal. Figure 13: The spectrum of cutting the vibration signal. Figure 13 indicates that the energy of the shearer cutting vibration signal is mainly concentrated in the frequency band range of 0 Hz-5000 Hz. The vibration signal of the C1 no-load cutting mode is caused by the hydraulic pump station, cutting motor, and gear reducer. There are mainly two frequency peaks of 480 Hz and 1310 Hz in the signal. The C2 cutting mode takes the simulated longwall coal face of the experimental plan 9 as the object, and there are two frequency peaks of 1160 Hz and 2190 Hz in the vibration signal collected. Compared with the vibration signal generated by the C1 no-load cutting mode, the frequency amplitude of the C2 cutting vibration signal is significantly increased, and the frequency peaks are different.