# Remotely Controlled Robot Swarms: A Structural Analysis and Model for Structural Optimization
## 1 Introduction
Currently, mobile robots are intelligent enough to provide self-navigation, which means travelling in a programmed path with small route corrections caused by obstacle detection. A higher level of intelligence involves finding the way based on the robot's current position and destination. Others navigate based on smell, vibrations, or air movements. For this study, a remote control signal generated by an operator simulated other steering signals. The intermediate solution is a remote control system supported by an operator who observes the robot and changes the movement direction. The robot has to be equipped with a remote control system added to the drive system and obstacle detection to avoid crashes. In the air, navigation is much easier than on the ground, where obstacles can be met [11]. The operator has to be awarene of the current situation, which can be achieved by using a camera mounted on the robot or an external observatory [12]. The basic robot system consists of:  
* A ground-driven platform
* A navigation system with obstacle detectors
* An actuator--a detector used in the searching system
* A control system
* A situational awareness system (with commonly used cameras)  
The model of the basic structure is presented in Figure 1.  
Currently, many kinds of driven platforms are available. The navigation system is much more complicated, although many types of obstacle detectors can be used. In some applications, such as path finding in a labyrinth, separate obstacle detectors can be omitted because they can be replaced by a driving algorithm. When a robot meets a wall, the resistance to movement and the motor's current increase rapidly, and the control system changes the movement direction in ta planned or random direction [13]. When a robot is controlled by an operator, s/he can observe its movement and lead it into a free space close to the assumed path. Current state of remote control systems. Usually, we use radio remote control devices. A radio frequency-coded signal is received and interpreted by radio-controlled devices, which pass the steering signal to the driving system. This is simple when a radio frequency (RF) control system is used only for one robot that is controlled with one frequency band. If we use a few robots working in the same band, they might disturb each other's signals, so we need as many separate frequency bands as we have robots. This is known as the frequency division multiple access (FDMA) technique. Another method of data exchange between a few transmitters and receivers is time division multiple access (TDMA). In this method, each transmitter-receiver pair works in the same frequency band, but they each have a separate and dedicated time period for the data exchange. Both techniques can be found in drones that are available for purchase on the Internet or in supermarkets. Examples and differences between the FDMA and TDMA systems are presented in Figure 2[14]. When a few robots have to be controlled separately at the same time, many operators are needed [15]. As the number of robots increases, so does the number of operators needed. A problem appears when we try to control a swarm of robots. It is very difficult to control all robots separately. When robots are in an action area, they work individually, according to programmed algorithms, after receiving the command to start the programmed mission. Moving all robots from place to place can be much more complicated if there is an obstacle to avoid. It would be useful if an operator could control all the robots as a whole. The adequate structure for such control requirements would be a swarm, which can be controlled as one body, and which transforms its shape to avoid obstacles. The individual robots would choose their path to avoid obstacles but try to keep themselves in a swarm structure [8]. Figure 1: The basic model of a remotely controlled robot. The main scientific and technical problem in this study was how to find the simplest structure of a robot that can cooperate with other robots in a swarm.