Foot Contact Interactions of a Clock Torqued Spring-Loaded Inverted Pendulum
The clock-torqued spring-loaded inverted pendulum (CT-SLIP) model describes the robust dynamic stability properties observed in most animals and some legged robots. However, the model’s behavior is sensitive to changes in liftoff conditions such as those experienced on realistic terrain. Here the incorporation of friction at the foot-ground interface is explored on the CT-SLIP model with specific interest in improving the transient center-of-mass dynamics. Multiple friction models are presented and tuned to reflect a periodic center-of-mass gait. The transient dynamics with friction are analyzed in comparison to the CT-SLIP model and improvements to the settling time and disturbance rejection were found. This addition of foot-ground contact friction may allow for better understanding of center-of-mass system dynamics on realistic terrain.