Analysis of Bending Ability of Soft Pneu-nets Actuators for Soft Robotics

Abstract

Background: There has been an increasing interest in the soft pneumatic networks (also referred to as pneu-nets) actuators for soft robotics due to their innate softness, ease of fabrication and high customizability. More and more structures of the soft pneu-nets actuators are reported in various relevant patents and papers. The bending ability of soft pneu-nets actuator is one of the key characterizing performances. It is characterized as a function of input air pressure as well as geometrical and material parameters, and influenced by the air pressures and design angle. Objective: In this paper, a new structure soft pneu-nets actuators (with different chambers morphology) was developed. The goal of this paper is to analyze the influence of the air pressures and design angle on the bending ability of the soft pneu-nets actuators with a new structure. Method: Firstly, a new structure of soft pneu-nets (adjusting chamber’s shape), based on the soft pneu-nets architecture described previously was developed. Then, the soft pneu-nets actuators were treated with a standard Finite Element Method (FEM) using the Abaqus 6.14 Computer-Aided Engineering (CAE) package. Several soft pneu-nets actuators with various design angles were analyzed to investigate the influence of the design angle on the bending ability. In order to investigate the effect of these parameters, the relationship between the angle of bending and these parameters was conducted. Thirdly, the influence of chambers morphology on the bending ability of soft pneunets actuators could be assessed. Results: When the air pressure P is under 13.5 kPa, with increase the air pressure, the difference of angle of bending under same design angle is less evident, but when the air pressure P is over 13.5 kPa, the difference of angle of bending at same design angle increase; At the same air pressure P, when the air pressure P is under 13.5 kPa, the difference of the angle of the bending between different design angle is less, The effect of gravity is greater than that of the air pressures P. When the air pressure P is over 13.5 kPa, the design angle shows more influential on the angle of the bending. Conclusion: The angle of bending increases with the increase of the air pressures P; the chambers with a bigger design angle (thinner inside walls) enabled greater bending at given air pressures P.