Fundamentals of soft robot locomotion

Abstract

Soft robotics and its related technologies enable robot abilities in several robotics domains including, but not exclusively related to, manipulation, manufacturing, human -robot interaction and locomotion. Although field applications have emerged for soft manipulation and human-robot interaction, mobile soft robots appear to remain in the research stage, involving the somehow conflictual goals of having a deformable body and exerting forces on the environment to achieve locomotion. This paper aims to provide a reference guide for researchers approaching mobile soft robotics, to describe the underlying principles of soft robot locomotion with its pros and cons, and to envisage applications and further developments for mobile soft robotics.

Bio‐inspired Design and Additive Manufacturing of Soft Materials, Machines, Robots, and Haptic Interfaces

“…[17,20,113,144] Inspired by the crawling behavior of soft-bodied land invertebrates such as worms,c aterpillars, and leeches,m obile soft robots with various crawling gaits have demonstrated unprecedented abilities to adapt to extreme environments. [160] This compliant adaptation, however,comes at the cost of agility.T oincrease the speed of locomotion, two strategies are usually taken by natural organisms:i )fast release of the stored elastic potential energy in the soft elastic tissues; ii)incorporation of rigid components,usually rigid legs,insoft bodies.The first strategy can be seen in the ballistic projection of atoadstongue, [161] and the ballistic rolling of acaterpillar, which has been successfully mimicked in as oft robot called GoQBot. [145] This principle has also been applied to create jumping soft robots powered by combustion.…”

“…Applications of soft robots in aerial and aquatic locomotion are distinguished by the incorporation of passive mechanisms.T he mechanical compliance of soft materials allows the components to passively yield to dynamic loads and produce aerodynamically or hydrodynamically favorable motions with less complex controls. [160,166,167] By storing and releasing the elastic potential energy in the soft materials, continuous motions that combine active and passive mechanisms-such as the wing morphing of flying animals and the undulation of fish-are achieved with soft robots. [168,169] With the advances in materials science and fabrication techniques, most notably 3D printing technologies,p rolific bio-inspired soft robots have demonstrated novel and competent abilities in aerial and aquatic locomotion.…”

“…[171] Although sharing the same adaptive features,t he wings of flying animals achieve shape changes by different approaches,a nd the mechanisms have inspired many biomimicking flying robots. [160] Birds change their wing shape through the active movement of joints,b ats actively stretch the wing surface by controlling the muscle fibers embedded within the wing, and insects have intrinsically flexible membrane wings that passively adapt to aerodynamic flow. [171] Some of these principles can be mimicked with rigid motors and joints,but the introduction of soft materials offers designs with greater similarity to the flying animals.…”

Bio-Inspired Octopus Robot Based on Novel Soft Fluidic Actuator

“…Bio-inspiration was often the driving force behind creating novel and innovative soft robots [2]- [5]. Soft robotics has not only challenged the fields of robot arms and manipulators, but also the area of mobile robots, whereby creating bio-inspired systems that are able to walk, crawl, jump, roll or swim [5]- [8]. One particular area, underwater exploration, can benefit very much from soft robotics solutions, as soft robots are able to easily mimic very complex movements of underwater creatures [9], [10].…”

A low-cost experimental rig for multi-DOF unsteady thrust measurements of aquatic bioinspired soft robots

“…Evidence of this is found in nature, where a large number of aquatic organisms exist that are partly or entirely devoid of skeletal structures. The growing interest from the robotics community for fish [2], [3], medeusae [4] and molluscs [5], [6] and other softbodied sea-dwelling organisms suggests that a proliferation of new aquatic bioinspired soft robots is likely to occur.…”