Experimental bending performance characterization of sHAMs used underwater growing robot

Abstract

Soft-growing robots represent an emerging field characterized by their ability to extend at the tip while the base remains stationary. These robots offer a unique advantage in navigating through confined spaces inaccessible to humans. Specifically, in underwater exploration tasks, their flexible bodies render them particularly efficient. Moreover, these robots exhibit the capability to steer even while growing. There exist several steering methods including sHAMs (soft Hydraulic Artificial Muscles), sPAMs (soft Pneumatic Artificial Muscles), tendon-driven techniques, and predefined bending mechanisms, applicable both in air and underwater [1],[2]. This paper specifically delves into the study of sHAMs (soft Hydraulic Artificial Muscles) and their inherent characteristics. Various critical factors influence the bending behavior of sHAMs, including pressure, the diameter ratio between the robot body and the sHAM, the length of the robot body, and the number of sHAMs employed. In this study, we concentrate on varying the diameter ratio between the body and sHAM, while keeping other parameters constant. To achieve this, we fabricated robot bodies with varying diameters while maintaining a constant diameter for the sHAM. By systematically analyzing the results obtained from this experimental setup, we aim to provide insights into how the bending angle varies in relation to the diameter ratio.