# Remotely Controlled Robot Swarms: A Structural Analysis and Model for Structural Optimization
## 3 Results
### Nonhierarchical, Random, or Organized Swarm  
Due to the results of previous analyses of hierarchical swarm structure, which show that all robots should have the same, quite developed structure, the analysis of basic swarms such as flocks of birds was considered. In flocks of birds or swarms of ants, all members change the direction of movement at the same time [18]. For avoiding problems of the limitation of frequencies, band, and time or operator physical burden, the concept of controlling all robots in a swarm with the same signal simultaneously was tested. According to it, each robot follows the same command respecting the others or the obstacles. If one common signal is used, there should not be a problem with signal interference or it taking too long to command the swarm. The pre-adopted robot structure developed for the array was used for analyses. The expected result is the simplification of the robot structure and its acting algorithms. The main assumptions for the rules of robot action in the swarm are as follows:  
* All robots receive control commands and follow them;
* All robots avoid other robots by keeping a defined distance from them;
* Robots detect obstacles individually and avoid them by following the other robots. Figure 16: The column change for followers of a failed robot. Figure 15: The effect of robot fault on swarm array. As robots affect each other, we can expect that a robot that has not received the command would be \"forced\" by the others to move the way they do. The structure presented in Figure 17 was used for analyses and simulations. Action 1: The swarm is moving ahead. The swarm is initially set in an array such as for a structural swarm. Due to the random resistance hampering robots' movement, the structure changes to a nonregular one. Results: The swarm keeps roughly to the assumed path. All robots started and stopped at the same time. The result for a swarm set in an array is presented in Figure 18.  
Results: The swarm is changing its dimensions: compressing in width and lengthening automatically to keep the appropriate distance between members. After passing through the \"corridor,\" the structure will be more regular. The result is presented in Figure 20. This is in accordance with our expectations. Effect. No change is needed. Action 4: The swarm is turning as a whole, controlled with one signal. Results: All robots change movement direction at almost the same time. The difference in speed and reaction delay cause the structure to change in a random way. However, the swarm is changing its movement direction as a whole. The simulated result is presented in Figure 21. The result is in accordance with our expectations. Effect: No improvement is needed. Action 5: The swarm is controlled by an operator to pass between obstacles on a rectangular path. Followers/slaves should follow it and avoid the obstacles. Results: The operator estimates the place of turning to pass the obstacle as a whole swarm. Robots are trying to keep their distance to neighbours by moving at different and variable speeds. As a result, the swarm changes shape. The area occupied by the robots is changing in some limited range. The operator has to estimate how to control the whole swarm at once. The result is presented in Figure 22, with the sequences of swarm position marked with numbers. Figure 21: The random organised swarm turning, controlled with one signal. Figure 20: The result of the simulation for scenario 3. Effects: The operator has to control the swarm by commanding the leader and observing the whole swarm. The identification of the leader, first row, and column members is needed to maintain the array. To avoid the obstacles without breaking the chain of the column, additional obstacle detectors are needed. So, each robot should be identified and have an ID marker. Action 6: The swarm is moving straight, but one robot in the swarm is broken down. Results: When one robot fails and is not marked as active, other robots treat it as the obstacle, and direct other robots to go around the broken one.