  This paper describes the use of spatially-sparse inputs to influence global
changes in the behavior of Dynamic Movement Primitives (DMPs). The dynamics of
DMPs are analyzed through the framework of contraction theory as networked
hierarchies of contracting or transversely contracting systems. Within this
framework, sparsely-inhibited rhythmic DMPs (SI-RDMPs) are introduced to both
inhibit or enable rhythmic primitives through spatially-sparse modification of
the DMP dynamics. SI-RDMPs are demonstrated in experiments to manage start-stop
transitions for walking experiments with the MIT Cheetah. New analytical
results on the coupling of oscillators with diverse natural frequencies are
also discussed.
