Bridging the reality gap - A dual simulator approach to the evolution of whole-body motion for the nao humanoid robot

We describe a novel approach to the evolution of whole-body behaviours in the Nao humanoid robot using a multi-simulator approach to the alleviation of the reality gap issue. The initial evolutionary process takes place in the V-REP simulator. Once a viable whole-body motion has been evolved, this evolved motion is subsequently transferred for testing onto another simulation platform - Webots. Only when the evolved kicking behaviour has been demonstrated to also be viable on the Webots platform is this behaviour then transferred onto the real Nao robot for testing. This eliminates the time-consuming process of transferring behaviours onto the real robot which have little chance of successfully crossing the reality gap, and also minimises the potential for damage to the real Nao robot and/or it's environment. By using this novel approach of employing two different simulators, each with its own individual strengths and weaknesses, we reduce the likelihood that any individual behaviour will be able to exploit individual simulators' weaknesses, as the other simulator should pick up on this weak point. Using this procedure we have successfully evolved ball kicking behaviour in simulation, which has transferred with reasonable fidelity onto to the real Nao humanoid.