NABI-S: A compliant robot with a CPG for locomotion

Abstract

The Non-Anthropomorphic Biped (NABi) has demonstrated agile motion without complex control due to its unique leg alignment in the sagittal plane. This paper presents NABi-S, a small version of NABi. The “S” designation refers to the new spring or “soleus” mechanism used to store energy and stabilize walking. An important feature of NABi-S is its ability to self-stabilize - it can recover from any tipping in the sagittal plane. Using this feature, NABi-S demonstrates stable motion using CPG control, a difficult task to achieve on a biped. In this paper, the soleus prototype is designed and analyzed. An open-loop, CPG algorithm is then implemented, and a parameter space search is performed to optimize robot locomotion.