An Invertebrate-inspired Approach to Design and Manufacturing in Soft Robotics

Abstract

Soft robotics has many potential applications including deep sea biological sampling, fruit picking, physical therapy, assistive devices, surgery and other grasping tasks; however, within that realm many soft actuators lack the ability to output high force. In order to attempt to overcome this challenge, many soft roboticists are interested in variable stiffness actuators, but soft-rigid hybrid robots may also be helpful in solving this challenge. In fact, many invertebrates are able to undergo large deformations and have the ability to change their stiffness. Many of these invertebrates integrate components such as spicules or ossicles, which are small bones, making the invertebrates essentially a soft-rigid hybrid system. Taking inspiration from these invertebrates, soft rigid hybrid systems can be designed to increase the capabilities of soft actuators. Within the field of soft robotics, there are many practical problems to be overcome in the development of soft-rigid hybrid hybrid machines, including design, manufacturability, and delamination between soft and rigid components. This thesis focuses on work towards addressing these problems. The work explores invertebrates and invertebrate-inspired soft-rigid hybrid robots as a framework for understanding constraints in soft robotic systems. It then proceeds to explore manufacturing techniques for creating cast soft-rigid hybrid robots. Following this, it explores a novel method for decreasing the delamination forces between rigid overmolded components and soft walls of actuators, and finally it concludes with steps towards creating a soft actuator that incorporates those components as well as a comparison to a rigid example using a linkage mechanism for grasping.