No abstract

Over the last decade, many bio-inspired crawling robots have been proposed by adopting the principle of two-anchor crawling or anisotropic friction-based vibrational crawling. However, these robots are complicated in structure and vulnerable to contamination, which seriously limits their practical application. Therefore, a novel vibro-impact crawling robot driven by a dielectric elastomer actuator (DEA) is proposed in this paper, which attempts to address the limitations of the existing crawling robots. The novelty of the proposed vibro-impact robot lies in the elimination of anchoring mechanisms or tilted bristles in conventional crawling robots, hence reducing the complexity of manufacturing and improving adaptability. A comprehensive experimental approach was adopted to characterize the performance of the robot. First, the dynamic response of the DEA-impact constraint system was characterized in experiments. Second, the performance of the robot was extensively studied and the fundamental mechanisms of the vibro-impact crawling locomotion were analyzed. In addition, effects of several key parameters on the robot's velocity were investigated. It is demonstrated that our robot can realize bidirectional motion (both forward and backward) by simple tuning of the key control parameters. The robot demonstrates a maximum forward velocity of 21.4 mm/s (equivalent to 0.71 body-length/s), a backward velocity of 16.9 mm/s, and a load carrying capacity of 9.5 g (equivalent to its own weight). The outcomes of this paper can offer guidelines for high-performance crawling robot designs, and have potential applications in industrial pipeline inspections, capsule endoscopes, and disaster rescues.

The resonant actuation of dielectric elastomer actuators (DEAs) can greatly amplify the power outputs and energy efficiencies and has facilitated numerous applications in soft robotics. In many circumstances, the DEAs are mounted on robotic bodies that are made of soft materials or compliant structures. Such compliant supports can demonstrate an equivalent stiffness and inertia comparable to the DEAs, thereby complicating the dynamics of the DEAs and threatening the performance and controllability of the soft robots by introducing additional degrees of freedom to the systems. Toward the goal of achieving reliable and controllable resonating actuation of the DEAs on soft robots, the effects of compliant supports on the dynamics of DEAs require dedicated investigations. By adopting a double cone DEA configuration, this work conducts a comprehensive study on the dynamics of a double cone DEA-compliant support system. A nonlinear dynamic model of the double cone DEA-compliant support system is developed. Together with experimental studies, the dynamics of the system in different support configurations are characterized and the influences of the key parameters in the system are clarified. The key findings of this work can potentially guide the designs of future high-performance DEA-driven soft robots.