A framework for embodied evolution with pre-evaluation applied to a biped robot

Abstract

Embodied evolution (EE) is a methodology in evolutionary robotics in which, without simulations on a host computer, real robots evolve on the basis of their interactions with the actual environment. However, when adopting EE, we had to accept robot behavior with a low fitness, especially in the early generations. This article introduces pre-evaluation into the EE framework for a biped robot in order to restrain the behavior of a robot of which the fitness is estimated to be low, especially falling down onto the ground. We provide a comparative discussion on the conventional simulate-and-transfer method, the original EE method, and the proposed one in terms of calculation time, cost of fitness evaluation, and cost of simulation or modeling based on the evaluation experiments. We believe that the EE framework with pre-evaluation is applicable to a wide variety of optimization tasks in which the cost or the risk of fitness evaluation is not negligible.