Multi-Mode Pneumatic Artificial Muscles Driven by Hybrid Positive-Negative Pressure

TL;DR

This paper presents a novel inflatable origami-inspired artificial muscle architecture driven by hybrid positive and negative pressures, offering versatile, lightweight, and programmable motions suitable for soft robotics and wearable devices.

Contribution

Introduction of IN-FOAM, a low-cost, flexible inflatable artificial muscle with programmable skeletons and multi-mode actuation capabilities, enhanced by multilayer and multi-channel designs.

Findings

IN-FOAM's force and contraction are tunable via hybrid pressure modes

Multilayer skeletons improve contraction ratios

Multi-channel skeletons enable multiple motion modes

Abstract

Artificial muscles embody human aspirations for engineering lifelike robotic movements. This paper introduces an architecture for Inflatable Fluid-Driven Origami-Inspired Artificial Muscles (IN-FOAMs). A typical IN-FOAM consists of an inflatable skeleton enclosed within an outer skin, which can be driven using a combination of positive and negative pressures (e.g., compressed air and vacuum). IN-FOAMs are manufactured using low-cost heat-sealable sheet materials through heat-pressing and heat-sealing processes. Thus, they can be ultra-thin when not actuated, making them flexible, lightweight, and portable. The skeleton patterns are programmable, enabling a variety of motions, including contracting, bending, twisting, and rotating, based on specific skeleton designs. We conducted comprehensive experimental, theoretical, and numerical studies to investigate IN-FOAM's basic mechanical behavior and properties. The results show that IN-FOAM's output force and contraction can be tuned through multiple operation modes with the applied hybrid positive-negative pressure. Additionally, we propose multilayer skeleton structures to enhance the contraction ratio further, and we demonstrate a multi-channel skeleton approach that allows the integration of multiple motion modes into a single IN-FOAM. These findings indicate that IN-FOAMs hold great potential for future applications in flexible wearable devices and compact soft robotic systems.