Power-Efficient Soft Pneumatic Actuator Using Spring-Frame Collateral Compression Mechanism

Sungjun Kim,Dongjun Shin,Seung Ryeol Lee,Dongun Lee,Sinyoung Lee

doi:10.3390/act11030076

Abstract

With the ongoing research on soft robots, the performance of soft actuators needs to be enhanced for more wide robotic applications. Currently, most soft robots based on pneumatic actuation are capable of assisting small systems, but they are not fully suited for supporting joints requiring large force and range of motion. This is due to the actuation characteristics of the pneumatic artificial muscle (PAM); they are relatively slow, inefficient, and experience a significant force reduction when the PAM contracts. Hence, we propose a novel PAM based on a spring-frame collateral compression mechanism. With only a single compressed air source, the external mesh-covered and inner spring-frame actuators of the proposed PAM operate simultaneously to generate considerable force. Additionally, the design of the internal actuator within the void space of PAM reduces the air consumption and consequently improves the actuator’s operating speed and efficiency. We experimentally confirmed that the proposed PAM exhibited 31.2% greater force, was 25.6% faster, and consumed 21.5% lower air compared to the conventional McKibben muscles. The performance enhancement of the proposed PAM improves the performance of soft robots, allowing the development of more compact robots with greater assistive range.

Highlights

In the field of robots, various studies have been recently researched, such as collaborative mobile robots that can interact with humans to improve their quality of life [1–3]
Soft pneumatic artificial muscle (PAM) cannot be adopted to an auxiliary system requiring large actuation stroke and force [14–16]
This is because the actuation force of PAMs decreases significantly with respect to the actuation stroke, making them inapplicable to large range of motion (RoM) systems [17]

Summary

Introduction

In the field of robots, various studies have been recently researched, such as collaborative mobile robots that can interact with humans to improve their quality of life [1–3]. Owing to the back drivable actuation characteristics, soft PAMs afford inherent safety [9] Their high force-to-weight ratio makes them a strong candidate for safe human–. Robot interactive tasks due to the minimization of the mass and inertia of the end–effector of robots [10] Owing to these unique characteristics, soft PAMs have potential in the field soft robots [11–13]. Despite their advantages, soft PAMs cannot be adopted to an auxiliary system requiring large actuation stroke and force [14–16]. Pneumatic actuators generally necessitate excessive overheads for input energy sources (compressed air), such as large air compressors, regulators, etc These characteristics of PAMs further complicate their applicability for mobile soft robots [18,19]

Objectives

Methods

Findings

Conclusion