AUTHOR=Espinal Andres , Rostro-Gonzalez Horacio , Carpio Martin , Guerra-Hernandez Erick I. , Ornelas-Rodriguez Manuel , Sotelo-Figueroa Marco TITLE=Design of Spiking Central Pattern Generators for Multiple Locomotion Gaits in Hexapod Robots by Christiansen Grammar Evolution JOURNAL=Frontiers in Neurorobotics VOLUME=Volume 10 - 2016 YEAR=2016 URL=https://www.frontiersin.org/journals/neurorobotics/articles/10.3389/fnbot.2016.00006 DOI=10.3389/fnbot.2016.00006 ISSN=1662-5218 ABSTRACT=

This paper presents a method to design Spiking Central Pattern Generators (SCPGs) to achieve locomotion at different frequencies on legged robots. It is validated through embedding its designs into a Field-Programmable Gate Array (FPGA) and implemented on a real hexapod robot. The SCPGs are automatically designed by means of a Christiansen Grammar Evolution (CGE)-based methodology. The CGE performs a solution for the configuration (synaptic weights and connections) for each neuron in the SCPG. This is carried out through the indirect representation of candidate solutions that evolve to replicate a specific spike train according to a locomotion pattern (gait) by measuring the similarity between the spike trains and the SPIKE distance to lead the search to a correct configuration. By using this evolutionary approach, several SCPG design specifications can be explicitly added into the SPIKE distance-based fitness function, such as looking for Spiking Neural Networks (SNNs) with minimal connectivity or a Central Pattern Generator (CPG) able to generate different locomotion gaits only by changing the initial input stimuli. The SCPG designs have been successfully implemented on a Spartan 6 FPGA board and a real time validation on a 12 Degrees Of Freedom (DOFs) hexapod robot is presented.