Designing soft robots poses considerable challenges: automated design
approaches may be particularly appealing in this field, as they promise to
optimize complex multi-material machines with very little or no human
intervention. Evolutionary soft robotics is concerned with the application of
optimization algorithms inspired by natural evolution in order to let soft
robots (both morphologies and controllers) spontaneously evolve within
physically-realistic simulated environments, figuring out how to satisfy a set
of objectives defined by human designers. In this paper a powerful evolutionary
system is put in place in order to perform a broad investigation on the
free-form evolution of walking and swimming soft robots in different
environments. Three sets of experiments are reported, tackling different
aspects of the evolution of soft locomotion. The first two sets explore the
effects of different material properties on the evolution of terrestrial and
aquatic soft locomotion: particularly, we show how different materials lead to
the evolution of different morphologies, behaviors, and energy-performance
tradeoffs. It is found that within our simplified physics world stiffer robots
evolve more sophisticated and effective gaits and morphologies on land, while
softer ones tend to perform better in water. The third set of experiments
starts investigating the effect and potential benefits of major environmental
transitions (land - water) during evolution. Results provide interesting
morphological exaptation phenomena, and point out a potential asymmetry between
land-water and water-land transitions: while the first type of transition
appears to be detrimental, the second one seems to have some beneficial
effects.

本文介绍了一种强大的进化系统，对不同环境下行走和游泳软机器人的任意形态进化进行了广泛研究，按照三组实验的方式进行探究。结果表明，不同材料在进化软体运动方面具有不同的影响，在我们简化的物理世界中，更加坚硬的机器人在陆地上的步态和形态更为复杂和有效，在水中表现也更好。研究还提出了关于环境转换对形态再适应现象的有趣观察，并指出了在陆地 - 水和水 - 陆转换之间的潜在不对称性：第一种转换似乎具有不利影响，而第二种转换似乎有某些益处。