Increasing the Payload and Terrain Adaptivity of an Untethered Crawling Robot Via Soft-Rigid Coupled Linear Actuators

This is the authors' abstract. We don't add key points for this paper.

Fluidic Elastomer Actuators (FEAs) provide new opportunities for developing agile, adaptive, and strong mobile robots for field explorations. In this letter, we propose a soft-rigid coupled linear FEA with a bio-comparable energy density of 10.9 J/kg at 50 kPa. This actuator achieves an increased blocked force output (318%), increased energy density (183%), and increased power density (358%) by incorporating a rigid carbon-fiber telescopic shaft within its elastomeric skin. Based on this new FEA, we develop an untethered crawling robot with enhanced capability of forward locomotion and vertical load-bearing. We analyze and demonstrate how the proposed actuators increase the crawling robot's payload and terrain adaptivity. Experiments demonstrate that the robot's crawling speed with a payload of 6 kg (8.8 times of its own weight) is effectively increased compared with robot with purely soft actuators. Furthermore, we have demonstrated the robot can adapt to terrains with a wide range of roughnesses. Our design of coupling soft and rigid components provides a feasible strategy for building FEAs with higher energy density and constructing FEA-based, untethered mobile robot with better locomotion and payload performance driven by low-power pumps.