## 4 Analysis of the Experimental Results
### Inclined-Sumping Running Positioning Experiments
#### 4.2.1 Identification of the Curved Section  
Identification of the curved section of the scraper conveyor is the key to accurate positioning of the shearer. It is mainly determined by analyzing the output signal of the gyroscope. Both the angular velocity curve directly output by the gyroscope and the heading angle curve obtained after compensation in Schemes 5-10 are shown in Figure 9.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Scheme** & **Sumping Position (m)** & **Running Time (s)** \\ \hline No. 5 & 0.2 & 60 \\ No. 6 & 0.2 & 120 \\ No. 7 & 0.9 & 60 \\ No. 8 & 0.9 & 120 \\ No. 9 & 1.6 & 60 \\ No. 10 & 1.6 & 120 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Test scheme design of the shearer feeding operation.  
Figure 8: Map matching results at different runtimes.  
Figure 9: Angular velocity curves and the heading angle curves after compensation.  
The angular velocity curve output by the gyroscope shows that, when the shearer moves in a straight line, the output signal of the gyroscope fluctuates around zero, the fluctuation range is small, and the overall change trend is also small. When the shearer enters the curved section, the output signal is significantly increased, which is obviously different from the signal when the shearer moves in a straight line. At the same time, the signal from the curved section is biased below zero first, and then biased above zero, showing obvious symmetry, which is consistent with the characteristics of the shearer sumping process. When the shearer exits the curved section, the gyroscope output signal keeps fluctuating around zero, and linear motion state characteristics are clearly reflected.  
In the above six schemes, the data processing process still consists of 10-point smoothing preprocessing, zero bias compensation and Kalman filter compensation, and the heading angle curve is obtained after compensation. The change in the heading angle mainly includes three parts. The heading angle fluctuates around zero when the shearer moves in a straight line. When the shearer enters the curved section, the heading angle gradually changes to a negative number, then gradually changes to zero. Finally, the heading angle changes little and tends to be stable when the shearer moves in a straight line again. The theoretical value of the heading angle in the curved section is 5\({}^{\circ}\), and the theoretical value of the heading angle at the endpoint is zero. The maximum values of the heading angles and the values of the heading angle at the endpoints of the experiments are given in Table 4.  
It can be seen from Table 4 that there is an error between the heading angle measured by the gyroscope in the curved section and the theoretical value. Moreover, the errors in certain experiments are large. However, it is easy to judge whether the shearer enters the curved section via a comparison with the data result of the straight running experiment. There is also an error between the measured heading angle and the theoretical value at the endpoint, mainly because the experimental device does not use a thermostat to suppress the temperature change in the instrument; therefore, the zero bias caused by the gyroscope and the temperature variation cannot be fully compensated.