# IoTactileSim: A Virtual Testbed for Tactile Industrial Internet of Things Services
## 3 Result and Discussion
### Scenario II: Haptic-Driven Remote Operations  
In this section, we will present the real-time control of the teleoperator in the virtual environment to mimic the real-world tactile industrial remote operations. Similar to the scenario I, II also consists of the master, slave, and network domain where virtual teleoperator developed in CoppeliaSim acts as salve domain. In the master domain, physical haptic devices (haptic computer mouse, glove, and hapkit) are used to interact with the virtual environment, as illustrated in Figure 11. These haptic devices are easy to develop because their supplementary material is available publicly for the research community. The tactile computer mouse was presented in [14], while the study in [23; 24] provide the design and development detail on a haptic glove and Hapkit, respectively. However, in this experiment, we only employed the (computer mouse and glove) to interact with the teleoperator as slave side. We mapped the physical computer mouse and glove X and Y direction to the XY coordinates of the developed virtual teleoperator in CoppeliaSim. The key focus of this experiment is to investigate the communication network parameters (latency, reliability) that affect the TI services. Additionally, it also demonstrates the potential of the proposed IoTactileSim to provide TI services under TI QoS/QoE requirements (1-5 ms). Human operators in the master domain use the haptic device to interact with the teleoperator at the slave side and receive haptic feedback. The interface of the IoTactileSim during direct controlling of the teleoperator in the virtual environment is depicted in Figure 11.  
To observe the effect of the number of data packets on latency for scenario II, the simulation results are summarized in Figure 12. These results also demonstrate that with the increase in the number of packets from 10 to 10,000, the network communication latency tends to decrease. In this experiment, we directly control the teleoperator in the virtual environment via a computer mouse in real-time. The control signals from the computer mouse are packetized as defined in (1), sampled as per haptic system requirement, and transmitted to the teleoperator using default parameters values as listed in Table 2. The teleoperator at slave side receives the control commands to perform the required task and backward the force feedback to the human operator. Figure 12a-d, indicates the results of the packet latency for the number of data packets 10, 100, 1000, 10,000, respectively. In Figure 12a with the number of packets = 10, the value of latency lies between 9-7 ms. In Figure 12b, up to 40 packets, latency value remains higher than 5 ms, and after that, the system gets convergence round trip latency around 2.5 ms. Similarly, the results in Figure 12c, gain a minimum latency value of 2.5 ms from the 20 th data packet to the 1000 th packet. To continue on a similar line as mentioned above, Figure 12d, exhibits a quick decreasing trend in round trip latency from 6 to 2.2\(\sim\)2.0 ms, as the number of data packets increases from 10, to 10,000. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Experiments**} & \multicolumn{3}{c}{**Packet Statistics**} \\ \cline{2-4}  & \multicolumn{2}{c}{**Dropped\(/\)Delayed (\%)**} & \multicolumn{1}{c}{**Out-of-Order (\%)**} \\ \hline \multicolumn{4}{c}{Haptic-driven remote operations} \\ \hline \multirow{4}{*}{**Local-time control**} & 10 & 100 (10 Packets) & 100 \\  & 100 & 44.0 (44 Packets) & 44.4 \\ \cline{1-1}  & 1000 & 3.10 (31 Packets) & 3.00 \\ \cline{1-1}  & 10,000 & 0.40 (39 Packets) & 0.30 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Cont. To elaborate this packet latency convergence in a better way, Figure 13 illustrates the histogram of the frequent data packets regarding packet latencies. The results in Figure 13c,d indicate that the packet latency reduces for an increase in the number of packets. The results in Figure 13c are similar to those in the previous section.