iSprawl: Design and Tuning for High-speed Autonomous Open-loop Running

TitleiSprawl: Design and Tuning for High-speed Autonomous Open-loop Running
Publication TypeJournal Article
Year of Publication2006
AuthorsKim, S., J. E. Clark, and M. R. Cutcosky
JournalThe International Journal of Robotics Research
Start Page903
Date Published09/2006

We describe the design features that underlie the operation of iSprawl, a small (0.3 kg) autonomous, bio-inspired hexapod that runs at 15 body-lengths/second (2.3 m/s). These features include a tuned set of leg compliances for efficient running and a light and flexible power transmission system. This transmission system permits high speed rotary power to be converted to periodic thrusting and distributed to the tips of the rapidly swinging legs. The specific resistance of iSprawl is approximately constant at 1.75 for speeds between 1.25 m/s and 2.5 m/s. Examination of the trajectory of the center of mass and the ground reaction forces for iSprawl show that it achieves a stable, bouncing locomotion similar to that seen in insects and in previous (slower) bio-inspired robots, but with an unusually high stride frequency for its size.