Shaping oscillations via mixed feedback

TL;DR

This paper presents a method for controlling oscillations in systems by combining positive and negative feedback, using dominance theory and harmonic balance to regulate oscillation frequency, with applications in locomotion.

Contribution

It introduces a complete design procedure for mixed feedback control of oscillations, integrating dominance theory and classical analysis methods.

Findings

Effective control of oscillation amplitude and frequency achieved.

Design procedure demonstrated on a two-mass system.

Potential applications in biomimetic locomotion systems.

Abstract

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.