Angelika Szengel:

Implementation of a behavior module for a biomimetic robot to simulate leading in fish shoal


Collective behavior research is a vast and complex field. Understanding the varying interaction patterns between members of a group and simulating them with the help of  models is a difficult and long process. But in recent years biomimetic robots gave rise to new chances of evaluating and verifying the state of the art in this field.

Leading is one key aspect in collective behavior. Decriphering its meachnism would gain the ability to immensely influence a whole group in a desired direction which in turn can be used in experimental setups for investigating social interactions e.g. foraging.

A biomimetic  robot can be perfectly exploited for this research question.  An implemented model will instantly verify in wet lab experiments whether its underlying logic is giving back the desired reaction from real living beings.

In this work, the model is a modified version of Couzin's zone model, adapted for leading behavior. In this model it is assumed that individuals try to keep the members of their group in a close zone around them. It got implemented in the framework of the RoboFish project as an automatic behavior module and got tested with guppies (Poecilia reticulata).

The results show that leaders can keep larger distances to other members of the group before forced to draw closer again. Followers do need to stay near other individuals to feel comfortable inside the group. Because of this distance relationship, leaders have more freedom in their choices and need to keep less track about the actions of the other members. As the robot is allowed to remove itself for longer distances before it is forced to travel back to the fish than the average guppy, it was indeed able to take the role of a leader several times.

As this work only presents an implementation which concentrate on few core aspects, the module gives promise for more insight into the mechanisms of  leading with future expansions considering additional factors in its code base.

Master of Science (M.Sc.)