# Method for Detecting Abnormal Activity in a Group of Mobile Robots
## 1 Introduction
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**No.**} & **Type of Mobile Robots** & **Features of Structural and Functional Characteristics** \\  & **Control Method** & \\ \hline \multirow{2}{*}{1} & \multirow{2}{*}{Remote control} & The radio channel is established directly between the operator and the mobile robot. The mobile robot executes those commands that it receives directly from the operator. \\ \hline \multirow{2}{*}{2} & \multirow{2}{*}{Independent control} & The mobile robot is pre-programmed and performs a specific sequence of actions. In addition, intelligent methods which allow the mobile robot to make decisions in unknown conditions could be used. \\ \hline \multirow{2}{*}{3} & \multirow{2}{*}{Overall control} & It is implemented using a star topology, where a radio channel is organized to transmit a signal between a server and a mobile robot, usually using a wireless router or radio station. \\ \hline \multirow{2}{*}{4} & \multirow{2}{*}{Group control} & It is organized using the ad hoc and mesh network. The wireless radio channel is used for communication between mobile robots. If it uses a fully distributed network structure, mobile robots could send packets to each other in multidirectional mode. Routing protocols are used to deliver packets to network nodes that are far apart from each other. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The types of Mobile Robots Control Method and ways of organizing and building the networks. Various protocols and standards can be used for the organization of these types of networks as presented in Table 2.  
It can be noted from Table 2 that the developers pay more attention to routing protocols. Indeed, routing in the networks of mobile robots is quite a difficult task, because it is necessary to deliver packets between any two nodes of the network, taking into account changing conditions. There were many methods and algorithms developed for organization of the group control system to manage the mobile robot. Overviews of the algorithms and methods of mobile robot control systems are presented in References [6; 7]. Despite the variety of methods and approaches to organizing group control of mobile robots, the main stages of the functioning systems can be distinguished. The main aim of the group control system (GCS) is the distribution of goals between mobile robots and planning the movement of nodes to their goals [8]. The scheme of the GCS is presented in Figure 1a. The mobile robotic control system is presented in Figure 1b. The task selection unit is responsible for assigning goals to each node. Nodes that receive the same goal are combined into one cluster. Regardless of the goal selection algorithm used, the goal selection unit relies on information received from other C\({}_{\text{R}}\) nodes [9]. \begin{table}
\begin{tabular}{c c c} \hline
**No.** & **Network Level** & **Communication Protocols** \\ \hline
1 & MAC (medium access control) level & IEEE 802.11 n,s, ZigBee, LODMAC (Location oriented directional MAC protocol for FANETs). \\ \hline
2 & Network layer &
\begin{tabular}{c} TBRPF (topology dissemination base on reverse-path forwarding), \\ DSR (dynamic source routing), GPSR (greedy perimeter stateless routing), OLSR (optimized link state routing protocol), DOLSR \\ (directional optimized link state routing protocol), AODV (ad hoc on-demand distance vector), HWMP (hybrid wireless mesh protocol) \\ \end{tabular} \\ \hline
3 & Transport level &
\begin{tabular}{c} TCP (Transmission Control Protocol), UDP(User Datagram Protocol). \\ TCP does not work well on mobile ad hoc networks (MANETs) and is \\ not suitable for use in flying ad hoc networks (FANETs). JAUS \\ (joint architecture for unmanned systems) is an emerging standard for \\ messaging between unmanned systems. \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 2: Types of protocols for mobile networks. Figure 1: Group control system diagram: (**a**) The scheme of the GCS.