# Multitarget Search Algorithm Using Swarm Robots in an Unknown 3D Mountain Environment
## 5 Simulation Experiment and Results  
The parameters are set based on actual search requirements, as shown in Table 2.  
Figure 4: Target search process. As an example, when \(n_{u}=40\), assuming that slopes in the mountain environment are all less than or equal to \(\beta\), a schematic of the target search process is shown in Figure 5. Figure 5a is a topographic map of the mountain area for target search. Figure 5b is the top view of the search area when \(t=1\), the robot is in a \(100\times 100\) area in the lower left corner, and the target is in an \(800\times 800\) area in the middle of the horizontal direction. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **Value** & **Parameter** & **Value** \\ \hline \(\alpha\) & 40\({}^{\circ}\) & \(\beta\) & 30\({}^{\circ}\) \\ \(n_{u}\) & 30–60 & \(N_{m}\) & 6 \\ \(n_{T}\) & 10 & \(m\) & 0.1 \\ \(n_{\phi}\) & 360 & \(\Delta l\) & 1 \\ \(Vm\) & 10 & \(Q\) & 10\({}^{5}\) \\ \(r_{com}\) & 300 & \(c_{1}\) & 1 \\ \(r_{obs}\) & 100 & \(c_{2}\) & 1.2 \\ \(r_{tar}\) & 100 & \(\omega\) & 0.5 \\ \(d_{0}\) & 10 & \(\lambda\) & 0.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameter values. Figure 5: _Cont._  
In Figure 5c, \(R_{2}\) detects the signal of target \(tar_{8}\), and robots \(R_{6}\), \(R_{15}\), \(R_{22}\), \(R_{23}\), and \(R_{27}\) join the suballiance. In Figure 5d, from \(t=1\sim 58\), \(R_{2}\), \(R_{6}\), \(R_{15}\), \(R_{22}\), \(R_{23}\), \(R_{27}\), \(R_{8}\), \(R_{10}\), \(R_{11}\), and \(R_{17}\) in the suballiance participate in the search for \(tar_{8}\), and \(R_{10}\) searches for \(R_{10}\) at \(t=58\). In Figure 5e, when \(t=127\), the robots successfully complete the search for target \(tar_{1}\). By this time, 5 targets (\(tar_{1}\), \(tar_{7}\), \(tar_{6}\) and \(tar_{8}\)) have been found. In Figure 5f, \(t=1\)-\(185\), \(11\) robots including, \(R_{5}\), \(R_{7}\), \(R_{11}\), \(R_{17}\), \(R_{18}\), \(R_{19}\), \(R_{20}\), \(R_{22}\), \(R_{24}\), \(R_{28}\), and \(R_{32}\), participate in the collaborative search for target \(tar_{2}\), and before this, multiple robots participated in the cooperative search for other targets. In Figure 5g, \(t=255\), the robot swarm finally found all 10 targets. In Figure 5h, all robot movement tracks of swarm robots in the search for targets are shown, and the robots successfully found all ground targets. Taking the number of robots \(n_{u}=30,\ 40,\ 50,\ \text{or}\ 60\) and the number of targets \(n_{T}=10\), the experiment was repeated 30 times, and the following data as shown in Table 3.  
After verifying the effectiveness of the swarm robot target search in a mountain environment with a slope less than or equal to \(\beta\), the existence of an environment with a slope greater than \(\beta\) in a mountain environment is verified. Assuming \(n_{u}=40\), the mountain slope is less than or equal to \(\alpha\). A diagram of the target search process is shown in Figure 6.  
Figure 6a shows a mountain topographic map for the target search and the positions of the targets and robots when \(t=1\). Figure 6b is a top view of the search area. The areas marked in red indicate that each location within the region has a slope greater than \(\beta\) in one direction. Figure 6c shows the process of searching for target \(tar_{6}\). When \(t=48\), robot \(R_{37}\) detects the target signal of \(tar_{6}\) and forms a suballiance with robots \(R_{27}\), \(R_{30}\), \(R_{40}\), \(R_{23}\), and \(R_{17}\). The suballiance starts to search for target \(tar_{6}\). At \(t=53\), \(R_{21}\) also detects the target signal of \(tar_{6}\), joins the suballiance, and pushes \(R_{23}\) out of the suballiance. Finally, when \(t=62\), the target is found, and the suballiance is dissolved. It can be seen from the figure that when a robot is searching for a target, it can move in a direction with a smaller slope according to the 3D curved obstacle tracking algorithm and then smoothly search for a target in a region with a higher slope.