During stance, the actuators are mechanically decoupled from the leg and the stored energy is released. The trajectory is determined by the spring-mass physics and the state of the leg at impact. This design casts the controller as a function mapping three trajectory parameters to two control outputs once every hopping cycle. Our particular solution uses a combination of graph-search planning and feedback control. The planner searches to find sequences of foot placements and computes control outputs using numerical solution of a physical model.
Feedback control is computed once per bounce.
Experimental data from a planar prototype are included demonstrating navigation of simple artificial terrain.