Light-powered self-propelled trolley with a liquid crystal elastomer pendulum motor

Conventional liquid crystal elastomer (LCE)-based robots require complex controllers and bulky power supplies, limiting their applications in areas such as microrobots and soft robots. In this paper, a light-powered selfpropelled trolley with a LCE pendulum motor is proposed, and the dynamics of its self-propelled motion is investigated theoretically. Under steady illumination, the periodic radial contraction and relaxation of LCE can trigger the trolley to move forward through the self-rotation of the LCE pendulum. The coupling of the opticallyinduced deformation with its motion facilitates the energy input from ambient illumination to compensate for the damping dissipation so as to maintain the sustained motion. Through theoretical modeling and numerical calculations, three typical motion states of the LCE pendulum are identified, namely static state, self-oscillation state and self-rotation state. Among them, the LCE pendulum can propel the trolley when it is self-rotating. The influences of different physical parameters on the system motion are studied quantitatively. The results show that the period of the simple pendulum and the trolley speed can be controlled by adjusting the illumination range, optical intensity, damping coefficient of pendulum and damping coefficient of trolley. The light-powered selfpropelled trolley constructed in current paper does not require complex controllers or self-contained power supplies, and possesses the characteristics of simple structure, light weight and energy efficient, which is of latent applied value in microrobots, soft robots and other fields.