Modeling and experiments of a soft robotic gripper in amphibious environments

Abstract

This article presented the optimization parameter of a bidirectional soft actuator and evaluated the properties of the actuator. The systematic simulation was conducted to investigate the effect of the top wedged angle (the angle for the wedged shape of the actuator structure) of the chamber on the bending extent of the actuator when it is deflated. We also investigated the width of the actuator and the material combinations of the two layers with the relation to the deformation performance. A mathematical model was also built to reveal the deformation of the actuator as a function of the geometrical parameters of the inner chambers and the material properties. We quantitatively measured the bending radius and the actuation time of the actuator both in air and under water. Digital particle image velocimetry experiments were conducted under water to observe the flow patterns around the actuator. We found that the top wedged angle has a significant effect on the outward bending of the actuator when it is deflated, and 15 was found to be optimal for bending into a larger gripping space. The result shows that the actuator can deform much easier with a bigger width. Utilizing a soft gripper that was built by mounting four actuators to a three-dimensional-printed rigid support, we found that the prototype can grip objects of different sizes, shapes, and material stiffness in amphibious environments.

Soft Robotic Grippers

“…Galloway et al showed the manipulation of delicate deep reefs (Figure ) and Zhou et al reported picking up of various food items, such as a banana, a pear, a piece of tofu, and an egg, using the integration of special materials in the palms of the grippers: a memory foam sheet and a patterned elastomeric layer. Manipulation of objects in amphibious environment was demonstrated by Hao et al…”

Soft Robotics: A Review of Recent Developments of Pneumatic Soft Actuators

“…This table seeks to show the range and versatility different technologies possess. In Figure 12, for example, ECF's have very small applied forces from them for very precise movements at the cost of high power consumption due to the high pressurization requirement that inherently comes with ECF based actuators [77,123,126,127]. Knowing which situations certain soft robotic technologies are appropriate is beneficial to the ability to accurately model and create designs.…”

“…FEA model of a soft robotic actuator compared to experiment[123]. (a) Schematic of the chamber shape, (b) The maximum bending angles of the three actuators when deflated, (c) The FEA results of the three actuators at pressurization state (20 kPa).…”

Movement Detection in Soft Robotic Gripper Using Sinusoidally Embedded Fiber Optic Sensor

“…Materials with good stretchability can be used for building soft robots, with examples including shape memory alloys (SMAs) [2][3][4], shape memory polymers (SMPs) [5], electro-active polymers [6], acrylic [7] and silicone elastomers (i.e., polydimethylsiloxane (PDMS) [8] as well as silicone gel [4,9,10]). Soft robots that mimic the movement of animals have been explored, including a robot finger [8], soft cylindrical manipulator [11], soft gripper [12][13][14], starfish [4] and octopus tentacle [9]. Applications of soft robots for locomotion [4], bending and shape detection [11], movement detection [12], as well as temperature and strain sensing [8], have been demonstrated.…”