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Some Observations

A project log for Drone Swarm Control Algorithms

I want to look at control methods for swarms that can be adapted to problems in the real world.

Gene FoxwellGene Foxwell 05/18/2016 at 02:500 Comments

I have evolved several sets of parameters for the swarm. In each case the parameters where scaled between 0-1, concatenated into an array which formed a swarms "genome", and fed to an evolutionary algorithm. The fitness of each swarm was measured as 10000 - Total Iterations required to reach all the goals in the simulation.

Although the best solutions found where typically on par or better than my hand tuned version, they tended to solve the problem in a completely different way. Whereas in the hand tuned version shown in the youTube videos I provided in the logs so far the swarm members appear to co-operate with each other, evolved swarms have a much more random nature.

After much tinkering an debugging I think I have realized the reason for this - the current problem doesn't really benefit a lot from having many robots swarming into the secondary rooms at once. A few members of the swarm that appear to "specialize" in exploration are sufficient to find all the goals in the environment.

This posses two challenges, one foreseen, one not so much. The first is that of the goal, it may simply be the case that this particular task is best suited for the specialize approach and that provided a problem that requires co-operation to solve I can evolve some parameters that will result in the robots co-operation accordingly. The second is the question as to whether with a little tweaking, forcing the swarm to flock a bit better might produce better results.

I have also noticed that in regard to the parameters being used, two of the parameters - the distance that the drones will allow between one another, and the distance before emergency stop - tend to work best when they are varied from robot to robot. That is swarms in which these parameters are the same for every robot do not seem to perform as well as those where this value varies. I am not sure why this is happening yet and will need to study this a bit more to decide if this is a result of the robots design, or a bug in my simulation approach.

Finally there are a couple of research papers I am looking at right now to mine for ideas to improve how the static swarm members co-operate. How much of these ideas I will use is not yet clear as I am still reading these over, however they are listed here for completeness:

[1] https://www.eecs.harvard.edu/ssr/papers/robio10-nhoff.pdf

[2] http://people.idsia.ch/~foerster/2013/02/SwarmanoidPaperTR.pdf

So now I have few avenues of approach that I need to work on to move this project along. I still need to work on the adaptive features I've mentioned in the past. I think this is best done with the hand tuned version of the algorithm where the machines actually do seem to have "flocking" behavior. I need to introduce goals make co-operation a pre-requisite for completeness, examine the effects of the distance / emergency stop parameters to see why they have the effects I have observed, and finally incorporate any useful ideas I can find in the literature to see if the overall system's behavior can be improved as a result.

I will report on each of the aforementioned fronts as progress is made. Github will be updated with my latest simulation code in the morning to ensure that everything is up to date.

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