Stepwise self-oscillation of a photo-oscillator via time delay

Abstract

Self-oscillating systems, characterized by ambient-energy-supply and self-control, can absorb energy from steady environment to sustain continuous motion, whereas traditional self-oscillations rely on inertia and require rapid response to excitations. This study introduces a time-delay mechanism to experimentally design a photo-oscillator based on liquid crystal elastomers (LCEs), demonstrating stepwise self-oscillation without requiring a rapid response of the LCE to stimuli. The time delay is realized using a bistable seesaw system and is explained through the time history of the stepwise self-oscillation. Through quasi-static analysis, critical positions determined by geometric conditions are calculated, revealing the photo-oscillator alternates continuously between two stable states. Furthermore, the influence of system parameters on the critical contraction and period is investigated. Unlike many existing self-oscillating systems, the proposed photo-oscillator features a simple structure, a wide controllable oscillation period, and minimal requirements, relying only on small-area line illumination. The findings of this study hold promise for expanding design concepts applicable to soft robotics, sensors, and energy harvesters.