Heat-driven self-wobbling of a liquid crystal elastomer double-wheel linkage

Heat-driven self-sustaining systems can absorb heat from the surrounding environment to maintain their own motion, and therefore have broad application prospects in the fields of energy harvesting, signal transmission, and micro-mechanical robotics. It is difficult to experimentally realize the self-sustaining oscillation phenomenon of monostable dynamic, such as that of a pendulum, because sufficient net work cannot be provided. This paper adopts an efficient heat transfer method through contact, which can provide enough net work to achieve self-sustaining oscillation. Based on the existing mature dynamic LCE model and combining it with Hamilton's principle, we establish a theoretical model for the heat-driven self-wobbling liquid crystal elastomer double-wheel linkage system and elucidate the mechanism of self-wobbling. Numerical calculations show that the system exhibits two modes of motion: static mode and self-wobbling mode, which is consistent with experimental results. The LCE double-wheel linkage system compensates for damping dissipation during motion by absorbing thermal energy from a hot plate, thereby maintaining its self-wobbling behavior. Additionally, this paper also studies in detail the effects of several key parameters on the amplitude and frequency of self-wobbling. In particular, the amplitude of the self-wobbling exceeds three times the transverse dimension of the rod, and the frequency of self-wobbling can reach 5 Hz, which is considered high-frequency oscillation at this scale. The significant oscillation amplitude is caused by the amplification effect of the wheel-axle mechanism, while the high-frequency oscillation results from the unique structural feature that enables the LCE rod to rapidly move in and out of the high-temperature zone. This self-wobbling liquid crystal elastomer double-wheel linkage system has the advantages of high amplitude, strong stability, simple structure, and flexible adjustment. It is expected to play an important role in practical application scenarios such as signal transmission, energy capture, and micro-robotics.