Characterization of 3D printed pneumatic soft actuator

Soft robotics have been investigated to replace rigid systems due to the necessity of a safe interaction between robots and humans. These types of systems are composed of soft actuators, which create motion of the structure in a linear or rotational trajectory. Soft actuators can be made using different manufacturing processes, but the most common is mold casting. However, this manufacturing process involves several steps increasing the manufacturing time and hindering design changes. This study presents a novel design of a fully 3D printed soft pneumatic actuator, using fused deposition technology. The actuator was manufactured using the most flexible material for fused deposition printing available on the market, with a shore hardness of 60 A. This paper presents a characterization of the performance of the soft actuator under different pressure conditions. Computational simulations were made to predict the response of the soft actuator, based on previous mechanical characterization of the flexible printed material. The results were compared with the experimental measurements. The theoretical model is able to predict the response of the printed actuator with an error of less than 7%. The bellow actuator was able to bend 120° at 25 psi. Additionally, the dynamic response of the soft actuator was characterized based on three different parameters: load, frequency of pressurization, and pressure level. High values of pressure produce higher deformations and greater displacements; and load reduces the damping of the dynamic response of the actuator producing more vibration and less stabilization. Finally, two different gripper designs were tested based on the opening and closing movements of single bellow actuators. Both designs were capable of holding and lifting more than twice the actuator's weight. The functionality of both designs were simulated and tested experimentally.