On the Dynamics of Bounding and Extensions Towards the Half-Bound and the Gallop Gaits

This paper examines how simple control laws stabilize complex running behaviors such as bounding. First, we reveal and discuss the unexpectedly different local and global forward speed versus touchdown angle relationships in the self stabilized SLIP model. Then we show that, surprisingly, even for a much more complex, energy conserving quadruped model, many cyclic bounding motions exist, which can be locally, open loop stable! The success of simple bounding controllers motivated the application of similar controllers for asymmetric gaits and resulted in the first experimental implementations of the half-bound and the rotary gallop on our Scout II quadruped.