Eccentric High-Force Soft Pneumatic Bending Actuator for Finger-Type Soft Grippers

Abstract

Soft pneumatic actuators (SPAs) play an important role in leading the development of soft robotics. However, due to the inherent characteristics of soft materials, the low driving force limits the application of SPAs. This study presents a high-force soft pneumatic bending actuator (SPBA) that consists of a spring, an eccentric silicone cylinder, and a limiting fiber. Based on the Neo-Hookean model, a theoretical model is established to predict the relationship between the bending angle and pressure of SPBA. Furthermore, we characterize the performance of SPBA in terms of the bending capability, tip force, as well as response time. The results demonstrate the effectiveness of the theoretical model, as well as the high tip force (10.2 N) and fast response capability of SPBA. Finally, SPBAs are used to construct a three-finger soft gripper. The load capacity of the gripper is proofed, which indicates that the gripping force of the gripper increases with the pressure of the fingers and the diameter of the object. The gripping test of the gripper is performed. The result shows that the gripper with pinching mode can grip objects with various sizes and shapes in the air and underwater, and the gripper with enveloping mode can grip objects with weight up to 1.25 kg.

Advanced Technologies and Applications of Robotic Soft Grippers

“…Considering the linear characteristics of pneumatic output, the way of directly mapping the output through the actuating device (Figure 9b) has become a classic control method of pneumatic soft gripper. [115,124,125,166,167] Teeplet [20] further constructed a more flexible double-knuckle soft gripper by modeling and designing the proximal actuate of multiple knuckles. However, this linear mapping method is also limited by the linear relationship, and can not achieve a good control effect.…”

“…Reproduced with permission. [ 125 ] Copyright 2022, American Society of Mechanical Engineers. d–f) Hydraulically driven gripper, hydraulic, and pneumatic drives have similar characteristics.…”

Analysis modeling and experiment of bionic winding soft actuator inspired by plant tendrils

“…The response of soft actuators to external stimuli is an important index to measure the performance of soft actuators [32]. In the response speed experiment of soft actuator, air pump is used as the only power source for analysis.…”

A bioinspired modular soft robotic arm

“…Soft materials have shown a high degree of compliance to conform to different shapes, as observed in silicone elastomer grippers, allowing them to manipulate delicate objects [3,5,26,27]. Furthermore, the flexibility of soft materials, such as fabrics, has resulted in innovative designs that utilize the Japanese art of origami [16], incorporating pleats and folds to minimize size while retaining the capacity to unfold and expand [28].…”

“…Moreover, unlike traditional robotic devices, which are conventionally actuated via electric motors, soft robotics can be actuated via pneumatics, cable-driven motors, dielectrics, and shape memory alloys (SMAs) [27,29,30]. Pneumatic actuation is becoming increasingly popular owing to its weight and power generation, enabling soft robots to be comparable to traditional robots [31,32].…”