Compliant Leg Shape, Reduced-Order Models and Dynamic Running

The groundbreaking running performances of RHex-like robots are analyzed from the perspective of their leg designs. In particular, two-segment-leg models are used both for studying the running with the legs currently employed and for suggesting new leg designs that could improve the gait stability, running efficiency and forward speed. New curved compliant monolithic legs are fabricated from these models, and the running with these legs is tested by using a newly designed running test robot. Both the simulations and the experimental trials seem to suggest that running with legs with unity-ratio of the leg segments is faster and more efficient than running with the leg that is currently used on the RHex-like robots. The simulation model predictions seem to match closely to experimental trials in some instances but not always. In the future, a more sophisticated model is needed to capture the actual running with curved legs more accurately.