  We study the problem of controlling oscillations in closed loop by combining
positive and negative feedback in a mixed configuration. We develop a complete
design procedure to set the relative strength of the two feedback loops to
achieve steady oscillations. The proposed design takes advantage of dominance
theory and adopts classical harmonic balance and fast/slow analysis to regulate
the frequency of oscillations. The design is illustrated on a simple two-mass
system, a setting that reveals the potential of the approach for locomotion,
mimicking approaches based on central pattern generators.

Systems and Control;Systems and Control