Many Samples Combining to form one Complex Unit
Have you ever noticed ants, and ever wonder how they go about their ‘exploratory business’ in trying to find food, and once one of them does, within no time their ‘fellow explorers’ gather around it and coordinate themselves to transport the food? Have you may have looked at beehives and wondered how they make them? Well, some bright minds did and wanted to find out how. So then they started modeling these insects to find out how they do what they do. The bottom line of their findings was:-
These insects are all identical, they perform their own small tasks, and although they can communicate with their fellow insects, they have no knowledge of the whole operation, which is performed by a multitude of such insects.
So what began as an exercise in understanding nature, turned into an engineering problem:’Can we use multiple simple systems to perform a task beyond the capability of any one?’ What came out of this was a branch of robotics called ‘Swarm robotics’.
Swarm robotics deals with the coordination of a large number of simple robots such that a collective behavior can be brought out by these robots interacting with each other and the environment. So they perform a main complex task, but the point is that they do so without any master or main unit controlling or supervising their work. This reduces the effort required to build and maintain complex systems to solve a task.
The main features of these robots are
- They are autonomous(they can navigate and move about on their own)
- homogeneous(all of them are identical),
- The control rules allow for a large number of robots
- The task to be performed is too complex for any one robot to perform alone
- The robots are only capable of localized communication and sensing, this ensures that the coordination is distributed, so the system can be scaled to any number of robots you may require.
Popular areas of application of these bots include:-
- Area Coverage: Whenever there is a need to cover areas for applications like demining, search and rescue, exploration, etc. in large or irregular landscapes where control and positioning of all bots are difficult(underwater or extraterrestrial planet landscapes), it is more feasible to deploy robotic swarms that do not require central control, can detect and respond to changing environmental landscapes and can also take quick action(maybe block a leakage).
- Tasks involving expendable robots: Since the robots involved in robotic swarms are cheap, they can be used for operations after which the bots cannot be used again. An example of such a task is a search and recovery in a mine.
- Tasks involving scaling population: there are tasks for which it is not easy to know the number of resources required, examples of such tasks include containing oil spills. So for such applications, it is essential to have robust and scalable systems. Swarm robots do exactly this.
The main advantages robot swarms as compared to a single bot system are:-
- Improved Performance: As the tasks are distributed, they can be performed simultaneously by bots, increasing the throughput.
- Task enablement: If one bot can’t do it, use many bots to do it.
- Distributed Sensing and Action: The bots can sense more areas and can simultaneously act upon various spots.
- Fault Tolerance: If one bot fails, there are other bots to take its place. So the system as a whole is pretty immune to individual bot failures.
The main issues/challenges with swarm robotic systems are:-
- Interference: Robots in a group can interfere with each other through collisions, etc.
- Uncertainty of intention: A robot has no input to indicate what the other robot is doing. This can lead to robots obstructing each other rather than collaborating with each other.
Now if I have convinced you enough to maybe take some interest in Swarm Robotics (hopefully I have), you will want to know where to begin. The following two papers introduce the basic concepts of Robotic Swarms to get you started.
2.https://www.hindawi.com/journals/isrn/2013/608164/
– Article by Himanshu Dubara, 3rd year Electrical and Electronics Engineering