Co-evolution of morphology and control of soft-bodied multicellular animats

Abstract

We present a platform that allows for co-evolution of development and motion control of soft-bodied, multicellular animats in a 2-dimensional fluid-like environment. Artificial gene regulatory networks (GRNs) with real-valued expression levels control cell division and differentiation in multicellular embryos. Embryos develop in a simulated physics environment and are converted into animat structures by connecting neighboring cells with elastic springs. The springs connecting outer cells form the external envelope which is subject to fluid drag. Both the developmental program and motion control are encoded indirectly in a single linear genome, which consists of regulatory regions and regions that code for regulatory products (some of which act as morphogens). We applied a genetic algorithm to co-evolve morphology and control using a fitness measure whose value depends on distance traveled during the evaluation phase. We obtained various emergent morphologies and types of locomotion, some of them showing the use of appendages.