Earthworm-Inspired In-pipe Soft Robot (ESR): Design, Modeling, and Implementation

In this paper, the design, modeling, and fabrication of a pneumatically-driven soft robot that can travel through pipes by imitating the motions and capabilities of an earthworm are presented. The development of robots, which are similar to living creatures such as humans, invertebrates, and Mollusca, is rapidly growing. By adopting a specific construction, the in-pipe robot mechanism presented in this study can travel inside pipes to perform inspection duties that are sometimes difficult to access. This robot uses a longitudinal pneumatic actuator, which provides robot elongation; it moves by changing the coefficient of friction and the phase change between the internal gripper systems, which contain McKibben actuators to provide radial diameter changes. The internal gripper systems are attached to the ends of the robot. The suitability of the robot's function is indicated in various experiments. Based on the double-mass spring-damper system, the dynamic equation for the Earthworm-inspired Soft Robot (ESR) motion is obtained. For validation purposes, ADAMS is used to model the motion of ESR. Ultimately, when actual conditions are applied to the robot within the simulation, the robot performs the identical movement with a 16% velocity error. Compared to the results, it illustrates the validity of the theoretical models.