## 2 Research Equipment and Materials
### Research Equipment  
#### 2.2.1 Blockage Spray System  
Design and Development of the Blockage Spray System  
The blockage spray system, employed for spraying operations, shown in Figure 2, integrates various interconnected control systems, including PLC control, remote units, and sensors. It was designed to simulate contamination scenarios on the LiDAR sensor by spraying dust and absorbed materials in a controlled manner, thereby enabling subsequent data measurement and evaluation. Each component is interconnected via wireless communication and EtherCAT to maximize overall system efficiency. Furthermore, the blockage spray system, shown in Figure 3 and illustrated in Figure 3a,b, was designed for portability and effective targeting based on the target's position. To ensure consistent spraying orientation, a gimbal was used to maintain horizontal alignment with the target. The system is also equipped with a laser distance meter for real-time verification of the distance to the target, thereby ensuring a consistent spray distance. Furthermore, the experimental apparatus is equipped with sensors for measuring \begin{table}
\begin{tabular}{c c} \hline \hline
**Type** & **Specifications** \\ \hline \multirow{8}{*}{Sensor} & Number of Channels: 32 \\  & Range: 300 m (@ 80\%), 100 m (@ 10\%) \\ \cline{2-3}  & Horizontal Field of View: 135\({}^{\circ}\) \\ \cline{2-3}  & Horizontal Angular Resolution: 0.117\({}^{\circ}\), 0.234\({}^{\circ}\) (Optional) \\ \cline{2-3}  & Vertical Field of View: 10\({}^{\circ}\) \\ \cline{2-3}  & Vertical Angular Resolution: 0.3125\({}^{\circ}\) \\ \cline{2-3}  & Range Resolution: 4 mm \\ \cline{2-3}  & Range Accuracy: Up to 30 mm \\ \cline{2-3}  & Frame Rate: 25 fps \\ \cline{2-3}  & Wavelength: 905 nm \\ \hline \hline \end{tabular}
\end{table} 
Table 1: AutoL Co. G32 LiDAR specifications. Figure 1: (**a**) G32 LiDAR, (**b**) LiDAR plate dimensions, and (**c**) real LiDAR plate. temperature, relative humidity, and wind speed, thereby facilitating precise documentation of environmental conditions during the experiments. Figure 3: Blockage spray system. (**a**) Full view—3D; (**b**) full view—real; (**c**) nozzle part; (**d**) rail part; (**e**) reservoir tank; (**f**) temperature and humidity sensor; and (**g**) wind speed sensor. Figure 2: Blockage spray system configuration diagram. Figure 3c shows the spray nozzle, which is adjustable from 60\({}^{\circ}\) to 135\({}^{\circ}\)[12]. The inlet connection employs a fine atomization and fan control method. The maximum liquid spray pressure is 7 bar, which adequately covers the 3-5 bar pressure range targeted in this study. As shown in Figure 3d, spray uniformity is ensured by a rail system that facilitates lateral movement of the spray nozzle. Figure 3e shows that the system uses a bottom-discharge tank for test solution agitation, with an integrated air nozzle to provide continuous agitation and prevent sedimentation. Figure 3f illustrates sensors capable of measuring temperatures from \(-40\) to 80 \({}^{\circ}\)C and relative humidity from 0% to 100% RH, and they enable the monitoring of ambient conditions within the laboratory. Figure 3g presents a wind speed sensor designed to measure wind velocities ranging from 0 to 90 m/s. Performance Evaluation and Verification of the Blockage Spray System  
To verify the quantitative spraying performance of the blockage spray system, 30 repeated tests were conducted using the LiDAR window cover. Point cloud data were acquired at a rate of 10 Hz for 10 s using LiDAR software (AutoL Viewer V1.1.0), and average values were subsequently calculated. \[S=\sqrt{\frac{\sum(x_{i}-\overline{x})^{2}}{n-1}}\, \tag{1}\]  
\[SE(\%)=\frac{S}{\overline{x}},\ Spray\ uniformity(\%)=(100-SE). \tag{2}\]  
Here, \(S\) is the standard deviation, \(x_{i}\) denotes the test results, \(\overline{x}\) is the average of the test results, \(n\) is the number of tests, and \(SE\) denotes the error in the uniformity of dust dispersion in the dust-spraying device.