Self-Sustained Collective Motion of Two Joint Liquid Crystal Elastomer Spring Oscillator Powered by Steady Illumination

Abstract

For complex micro-active machines or micro-robotics, it is crucial to clarify the coupling and collective motion of their multiple self-oscillators. In this article, we construct two joint liquid crystal elastomer (LCE) spring oscillators connected by a spring and theoretically investigate their collective motion based on a well-established dynamic LCE model. The numerical calculations show that the coupled system has three steady synchronization modes: in-phase mode, anti-phase mode, and non-phase-locked mode, and the in-phase mode is more easily achieved than the anti-phase mode and the non-phase-locked mode. Meanwhile, the self-excited oscillation mechanism is elucidated by the competition between network that is achieved by the driving force and the damping dissipation. Furthermore, the phase diagram of three steady synchronization modes under different coupling stiffness and different initial states is given. The effects of several key physical quantities on the amplitude and frequency of the three synchronization modes are studied in detail, and the equivalent systems of in-phase mode and anti-phase mode are proposed. The study of the coupled LCE spring oscillators will deepen people’s understanding of collective motion and has potential applications in the fields of micro-active machines and micro-robots with multiple coupled self-oscillators.

Synchronization of a Passive Oscillator and a Liquid Crystal Elastomer Self-Oscillator Powered by Steady Illumination

“…In conclusion, the initial velocity does not affect the synchronous regime and inherent characteristics of self-oscillation of the two oscillators. The effects of initial velocity on self-oscillations of two coupled oscillators based on LCE fiber are the same as that in other self-oscillating systems [ 57 ].…”

“…The first exploration of synchronization originated from Huygens’s clock experiment [ 55 ], which observed that two identical clocks oscillated synchronously with two pendulums in opposite directions. Recent studies have confirmed that the synchronization between the two pendulums is caused by the coupling caused by micromechanical vibration propagating in the wooden structure connecting the clocks [ 56 , 57 ]. In addition, the synchronous movement of a large number of metronomes with greater degrees of freedom on a freely moving base was shown experimentally [ 58 ].…”

Heat-Driven Synchronization in Coupled Liquid Crystal Elastomer Spring Self-Oscillators

“…Li et al investigated the synchronization of two coupled light-driven self-oscillating LCE pendulums [ 7 ]. The collective motion of two joint LCE oscillators based on the self-shadowing effect was investigated by Du et al [ 73 ]. To achieve more functions and applications, further investigation is warranted to explore the synchronization phenomenon and its underlying mechanisms.…”

Thermally Driven Self-Rotation of a Hollow Torus Motor

“…In recent years, based on various stimuli-responsive materials including thermally responsive polymer materials [ 26 , 27 ], liquid crystal elastomers (LCEs) [ 28 , 29 , 30 , 31 ], dielectric elastomer [ 32 , 33 , 34 , 35 ], hydrogels [ 36 , 37 ], and ion gels [ 38 , 39 ], a wealth of self-excited motion modes have been proposed, such as rolling [ 40 , 41 ], vibration [ 24 , 31 , 40 , 41 ], torsion [ 41 , 42 ], stretching and shrinking [ 10 , 40 , 43 ], swinging [ 44 ], buckling [ 45 , 46 ], jumping [ 47 , 48 , 49 ], rotation [ 25 , 28 ], eversion or inversion [ 27 , 50 ], expansion and contraction [ 51 , 52 ], swimming [ 53 ] and even group behavior of several coupled self-excited oscillators [ 54 ]. The self-oscillating system is usually accompanied with damping dissipation, and its motion is a non-equilibrium dissipation process.…”