# Remotely Controlled Robot Swarms: A Structural Analysis and Model for Structural Optimization
## 4 Discussion  
Initially, the robot swarm based on a soldier array seemed to be easily controlled by controlling the leader. The intelligence of the leader would control the whole swarm. Initially, the structure with a leader was assumed to be the most complicated, but the need for following the leader and avoiding obstacles by followers and the importance of ensuring the swarm fault tolerance meant that the slave robots became more complicated. The leader, which is controlled by the operator, can be the least advanced robot in the swarm. The analyses and simulation show that a hierarchical structure following the soldier array is complicated and rather expensive to realize with an acceptable level of reliability. Controlling a swarm by controlling its leader demands from the operator a prediction of all swarm members' behaviour sequences. The obstacles in the field are avoided by the  
Figure 23: The effects of a robot fault on the swarm array. Figure 22: The track of the swarm guided by an operator in test 5 for a nonhierarchical structure. The sequences of swarm position are marked with numbers. operator, but individual obstacle detectors are required as well. Keeping the array in a hierarchical structure requires individual robot identification and a definition of their roles and positions in the array. This role should be changeable. For this reason, the opposite structure of a swarm--nonhierarchical, randomly organized, and applying the simplest rules--was investigated. The randomly organized swarm met our assumptions and appeared to be more resistant to failure and easier to control than the structural one. As the random swarm appeared to be resistant to communication breakdowns, it can be assumed that only one robot in the swarm is remotely controlled or programmed. When it is at the centre of a swarm, the whole swarm moves similar to it. We can notice a similar situation in a swarm of bees, where the queen is at the centre but decides the whole swarm's structure, as presented in Figure 24. When we have more than one robot that is moving in a different direction, the swarm will be broken into a few swarms. The intelligence and power of a swarm is based on the group-keeping algorithms, which are of the highest priority compared to other criteria. The majority of swarm members decide about the general direction of movement. Each member tries to keep at a distance from others and avoid obstacles. In the future, work on the problem of robot domination in a random organized swarm is planned. Knowledge of this will help us to avoid complications during command interpretation error by some robots in a swarm and to gain knowledge on animals' swarm dividing and joining mechanisms, which could be imitated in robotics. Two kinds of robot swarm organizations have been analysed. They were modelled with the same robot structure, but for the structural model, ordered speeds were calculated based on distances between robots. In the structural swarm, the distance between robots decided the speed limits, but the speed was ordered by RC. As the source of swarm intelligence, the high priority of distance-keeping has been pointed out. All results are the effect of it. An unstructured swarm of robots with simultaneous RC seems to be easier to be controlled than a structured one. Figure 24: A bee-like robot swarm. The structure and control algorithm of individual robots working in an unstructured swarm seem to be simpler and cheaper to achieve. Those robots do not need to identify their positions in the swarm but only keep their distance from others. The operator controlling the unstructured swarm as a whole does not need to make predictions of the behaviour and tracking of followers and leads the robots from place to place faster.