Modularity for maximum mobility and manipulation: Control of a reconfigurable legged robot with series-elastic actuators

We present a set of modular series-elastic actuators (SEAs) that allow rapid and robust prototyping of mobile legged robots. The SEA modules were originally developed for a snake robot, SEA Snake, and have recently been reconfigured into Snake Monster, a multi-modal walking robot that can be easily adapted to hexapod, quadruped, and biped configurations. The use of SEAs allows the implementation of a compliant hybrid controller using both position and force-based walking. This paper presents the mechanical design, control architecture, and initial locomotion experiments using the Snake Monster platform. Additionally, we discuss the enhanced capabilities, pertaining particularly to search and rescue applications, enabled by the use of our modular hardware. Finally, we highlight how these modules provide a powerful tool for both field deployment requiring locomotion and manipulation tasks.