A Novel Soft Bending Actuator Using Combined Positive and Negative Pressures

Abstract

Most soft pneumatic actuators for producing bending actuation have made use of either positive or negative pressure and adjusted their design in consequence. In the proposed paper, a novel soft bending actuator using combined positive and negative pressures (PNP) where the bending force of a negative pressure actuator and a positive pressure actuator is combined into a single actuating structure. This actuator is capable of producing a blocked force as high as 150 N at a combined positive pressure of 60 kPa and negative pressure of 60 kPa while still being able to produce large bending deformations. It was found that the equilibrium angle of PNP actuation is lower than using only negative pressure but that the actuator can produce larger forces at angles below the equilibrium angle of using positive pressure only. The actuator can use PNP actuation to produce large forces at lower bending angles and negative pressure actuation for producing large bending angles. This actuator was implemented in a soft robotic gripper capable of lifting large objects weighing up to 4 kg and a soft pinching gripper capable of holding a notebook weighing 1.85 kg by pinching it. The proposed actuator is capable of large forces and is versatile such that it is expected to be used in applications such as agriculture where many objects tend to be large and heavy yet require a delicate touch.

Soft and lightweight fabric enables powerful and high-range pneumatic actuation

“…1A, with more detailed parameters in table S3). Owing to the windable fingers, the grasping range of our gripper is significantly improved compared with conventional ones with fixed finger lengths (36,38,47,(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70). As well, the less stretchable fabric structure, together with the input pressure, renders the soft gripper insensitive to a high payload, making it one of the most powerful designs.…”

“…This new type of fabric-based pneumatic-driven robots enriches the field of soft robots while paving the way to develop more diversified human-friendly working robots. (56)(57)(58), ones reinforced by fiber (59)(60)(61)(62)(63), ones integrated with phase-changing materials (36,38,64), ones with soft-rigid hybrid structures (54,55,(65)(66)(67)(68), and ones consisting of multiple pouches (47,69,70). (B) Responses of different soft pieces to the same tensile load.…”

A 3D Printed Modular Soft Gripper Integrated With Metamaterials for Conformal Grasping

“…A soft robotic gripper can generate highly passive deformations and adapt itself to the shape of an object being handled due to its inherent compliance which is a characteristic of soft robotic systems (Laschi and Cianchetti, 2014). Many of the soft grippers are actuated using positive pressure, negative (i.e., vacuum) pressure, or a combination of positive and negative pressure (Fatahillah et al, 2020) soft pneumatic actuators. Based on soft pneumatic actuators and three-dimensional (3D) printing different soft grippers with complex topologies can be developed to generate various modes of deformation.…”

Hyperbaric Vacuum‐Based Artificial Muscles for High‐Performance Actuation

“…A linear actuator which is pressurized to extend and contracts through depressurization toward atmospheric pressure was shown to be able to produce contraction ratios up to 75%, [31] and an actuator was demonstrated where the deformable volume is maintained at room pressure and placed within a tube which is itself pressurized. [32] Linear and bending actuators making use of positive pressure chambers and negative pressure chambers have been demonstrated, [33,34] but the use of the positive pressure reduces the force of the actuator throughout the later part DOI: 10.1002/aisy.202200090 Existing pneumatic artificial muscles generally rely on the use of either positive or negative pressure for actuation with each having their own advantages and disadvantages. Herein, a hyperbaric vacuum-based artificial muscle (Hyper-VAM) making use of both positive and negative pressures almost interchangeably is described.…”