Inchworm Inspired Multimodal Soft Robots With Crawling, Climbing, and Transitioning Locomotion

Although many soft robots, capable of crawling or climbing, have been well developed, integrating multimodal locomotion into a soft robot for transitioning between crawling and climbing still remains elusive. In this work, we present a class of inchworm-inspired multimodal soft crawling-climbing robots (SCCRs) that can achieve crawling, climbing, and transitioning between horizontal and vertical planes. Inspired by the inchworm's multimodal locomotion, which depends on the $\Omega$ deformation of the body and controllable friction force of feet, we develop the SCCR by 1) three pneumatic artificial muscles based body designed to produce $\Omega$ deformation; 2) two negative pressure suckers adopted to generate controllable friction forces. Then a simplified kinematic model is developed to characterize the kinematic features of the SCCRs. Lastly, a control strategy is proposed to synchronously control the $\Omega$ deformation and sucker friction forces for multimodal locomotion. The experimental results demonstrate that the SCCR can move at a maximum speed of 21 mm/s (0.11 body length/s) on horizontal planes and 15 mm/s (0.079 body length/s) on vertical walls. Furthermore, the SCCR can work in confined spaces, carry a payload of 500 g (about 15 times the self-weight) on horizontal planes or 20 g on vertical walls, and move in aquatic environments.

Automated summary

This paper presents a class of inchworm-inspired multimodal soft crawling-climbing robots that can achieve crawling, climbing, and transitioning between horizontal and vertical planes. The robots are developed with pneumatic artificial muscles for body deformation and negative pressure suckers for controllable friction forces, allowing them to move at different speeds on different surfaces and carry payloads in confined spaces and aquatic environments.