The theme of ALIFE 2021 conference is ”Robots: The century past and the century ahead” , because we celebrate the centenary of Čapek's R.U.R. and the worldwide-used word “robot” , which comes from this play. The conference was originally scheduled to be held in Prague, the city where the play had its official world premiere in 1921. However, because of the covid-19 pandemic and its repercussions, ALIFE 2021 conference is virtual. Nevertheless, in this introductory paper the history of the R.U.R. play and its plot are briefly outlined and its legacy to current research discussed, namely in the context of the field of artificial life.

Collective behavior, swarming and mutual interactions between living entities are well-known phenomena in biology where, for example, flocks of birds or schools of fish are extensively studied. Swarming has also been observed in bacteria or tumor cell populations. This kind of collective behavior can be implemented also in non-living systems, namely in biologically-inspired swarm robotics. However, the collective behavior of chemical droplets (mutual interactions of multiple “liquid robots”) has not been studied before and the present paper reports the experimentally observed phenomena and modes of behavior in such system. We show how multiple decanol droplets in a thin layer of decanoate solution behave and interact. We report, for the first time, several life-like features such as collective chemotaxis and number-dependent group formation.

We describe experimentation with robots together with computer vision to improve various artificial chemical life systems. We investigate a case study, where the use of the robot enables timely, and precise verification of the experiment results with fixed parameters. In addition, new possibilities to promote the quality of artificial life experiments, such as positioning droplets at equidistant intervals or in patterns are discussed.