An earthworm-like modular soft robot for locomotion in multi-terrain environments

Abstract

Robotic locomotion in subterranean environments is still unsolved, and it requires innovative designs and strategies to overcome the challenges of burrowing and moving in unstructured conditions with high pressure and friction at depths of a few centimeters. Inspired by antagonistic muscle contractions and constant volume coelomic chambers observed in earthworms, we designed and developed a modular soft robot based on a peristaltic soft actuator (PSA). The PSA demonstrates two active configurations from a neutral state by switching the input source between positive and negative pressure. PSA generates a longitudinal force for axial penetration and a radial force for anchorage, through bidirectional deformation of the central bellows-like structure, which demonstrates its versatility and ease of control. The performance of PSA depends on the amount and type of fluid confined in an elastomer chamber, generating different forces and displacements. The assembled robot with five PSA modules enabled to perform peristaltic locomotion in different media. The role of friction was also investigated during experimental locomotion tests by attaching passive scales like earthworm setae to the ventral side of the robot. This study proposes a new method for developing a peristaltic earthworm-like soft robot and provides a better understanding of locomotion in different environments.

New topic horizons for drone systems and applications

“…Of great relevance to our journal is that geoscience drones may be used to explore both surface and subsurface processes, so this is not just an area for exploitation of aerial drones. Space drones could explore surfaces or atmospheres of other planets, earthworm-like drones (Das et al 2023; Fig. 2) could capture information about soils and edaphic processes, while underwater or under-ice robotic vehicles could send back information about deep ocean systems or processes under ice sheets (e.g., Meister et al 2019;Schmidt et al 2023).…”

“…2. A new peristaltic earthworm robot that could be useful for subsurface edaphic exploration (reproduced with permission from Duilio Farina and Riddhi Das from the Istituto Italiano di Tecnologia (see also Das et al 2023)).…”

Multimodal steerable earthworm-inspired soft robot based on vacuum and positive pressure powered pneumatic actuators

“…Except for this, there are few instances of earthworm-inspired soft robots at present [19,[22][23][24] utilizing the same control method and structures to achieve multimodal locomotion both in pipes and on surfaces without significant alterations to their fundamental structure. The robot developed by Tirado et al [22] employs a dual-tube wrapping approach, where inflation and deflation of different tubes enable multi-modal locomotion.…”

A Toolbox for Designing 3D‐Printing‐Ready Pneumatic Circuits for Controlling Soft Robots

“…This mechanism also brings other advantages in cost, manufacturability, and safety for human-robot interaction. Previous research has shown that soft pneumatic robots can execute various challenging tasks with much simpler control strategies compared to their rigid counterparts, such as locomotion over different terrains, [2,3] multimodal object grasping, [4,5] navigating through complex environments, [6] and so on. Despite the simplified control strategy and low computational cost required, many soft robots are still controlled by conventional rigid electronic systems such as rigid valves, pumps, microcontrollers, and motor drivers.…”