Soft Fluidic Actuator for Locomotion in Multi-Phase Environments

Abstract

This letter presents the design, development, and experimental assessment of a soft fluidic actuator that can enable locomotion in a variety of aquatic and terrestrial environments. Most actuation strategies for amphibious locomotion rely on rigid, fast moving components to generate thrust and tractive forces. Our prototype, comprising soft materials, and relying on simple motion planning and control strategies, demonstrates two gaits, that we employ for locomotion in two vastly different scenarios, underwater swimming and moving on granular terrain with varying levels of water content. By adjusting its internal pressure, the actuator dynamically varies its stiffness and shape, and transitions between wheel and soft paddle form. Experimental results of locomotion in controlled laboratory conditions serve as proof-of-concept for the proposed actuator's efficacy. Using two different motion patterns and control schemes, we show that this prototype achieves both thrust and tractive forces.

Multimodal Soft Robotic Actuation and Locomotion

“…Similarly, controlling the pressure in pneumatic actuators enabled the switching between wheels and paddles in another amphibious soft robot. [161] However, one disadvantage of soft robots is that they lose the advantages of engineering materials and strategies to exceed animal performance. A robot called Amphibious Robotic Turtle (ART) combines stimulus-responsive soft materials with traditional rigid robotics components, greatly improving the shapechanging of its limbs and gait control logistics for multimodal locomotion (Figure 9d).…”

“…Robots composed of soft materials and actuators provide a pathway for machines that can employ various gaits of movement or that can travel across multiple environments. [ 161 ] By incorporating different modes of actuation, more complex locomotion can be achieved. [ 162 ] Hence, using soft multimodal actuators with a variety of shape‐changing abilities is conducive to soft robots that are similarly capable of multiple locomotive modes.…”

“…Similarly, controlling the pressure in pneumatic actuators enabled the switching between wheels and paddles in another amphibious soft robot. [ 161 ]…”