Large-Deformation Electrothermal Actuation Inchworm-Like Crawling Robot Based on Bistable Structures for Load Carrying

Crawling robots have great potential in some harsh environments, but there are still some limitations, such as tiny structures that can only produce small deformation and poor load-carrying capacity. A lightweight inchworm-like crawling robot made of bistable structure driven by electrothermal actuation is proposed in this paper. The robot has the characteristics of large deformation and a certain extent of load capacity. The motion of the crawling robot was realized by the common effect of the bistable structure and the designed feet with anisotropic friction. The unstable transition process between snap-through and snap-back processes of the bistable structure was utilized to provide morphological deformation. Meanwhile the feet with anisotropic friction transformed the deformation to unidirectional movement of the crawling robot. Through electric experiments, the electrothermal driving influencing factors of bistable structure are tested, including heating time, maximum temperature and curvature change, which demonstrates the possibility of driving inchworm-like crawling robot with bistable structure and large-deformation. And the structure of the inchworm-like crawling robot assembled by a bistable shell pasted with an electric heating sheet and the designed feet with anisotropic friction. In order to evaluate the motion properties and load-carrying function of the inchworm-like crawling robot, the step length test under different voltages and the experiment of the crawling robot load-carrying capacity were completed. The results show that the crawling robot performs well in load-carrying, can achieve crawling movement under the condition of carrying 10 g and 20 g objects. The inchworm-like crawling robot provides a method to achieve large-deformation and load-carrying and demonstrates it is suitable in some extreme environments.