Self-sustaining chaotic characteristics of liquid crystal elastomer pendulum under different linear temperature fields

Self-sustaining chaotic motion systems based on active materials have broad application prospects in fields such as energy harvesting, artificial hearts and medical devices. This paper presents a self-sustaining pendulum system composed of a liquid crystal elastomer fiber and a mass sphere, which exhibits different self-sustaining motion laws under different linear temperature fields. By establishing nonlinear dynamic models of the system, the numerical simulations reveal that under concentric circular linear temperature field, the pendulum can exhibit three self-sustaining motion modes: periodic vibration, periodic swing and chaotic swing. In contrast, only periodic vibration and periodic swing occur under planar and non-concentric linear temperature fields. The research reveals the mechanism of the self-sustaining motion and explains the reasons why different linear temperature fields exhibit different motion laws. This system achieves self-sustaining motion by using the contracting work of liquid crystal elastic fiber to compensate for energy dissipation. And a key distinction is that self-sustaining chaos arises in the pendulum system with position-independent driving, but is absent when the driving is position-dependent. This research achievement not only deepens the understanding of the self-sustaining motion of the pendulum, but also provides new ideas for the development of chaotic robots.