TASP PhD Seminar – Lior Salem – “Soft robots actuated by controlled flow in embedded channel networks”

Work towards PhD degree under the supervision of Assoc. Prof. Yizhar Or and Assoc. Prof. Amir Gat

When: 17.2.2021 at 11:00

Where: zoom

Abstract: Soft robotics is a field that focuses on the analysis and design of robots with flexible structures that can continuously deform and change their shape and dimensions. Possible applications of soft robotics are autonomous locomotion across rough unstructured terrain while going through narrow passages and manipulating complex obstructed environments as in robotic minimally-invasive surgery. We focus on fluid-driven soft robots where actuation is achieved by controlling the pressure at inlets of a network embedded within the elastic solid, which induces changes in the stress fields exerted by the fluid on the solid body and causes deformations in desired patterns.

In this work, we introduce two types of soft actuators. First, we obtain a general solution scheme of an elastic beam, with significant solid inertia and fluid viscosity, actuated by a pressurized viscous fluid within a serpentine-shaped embedded fluidic channel. Second, we examine leveraging viscous peeling as a mechanism to create and activate soft actuators and microfluidic devices, including complex elements such as valves. We propose a theoretical model describing the dynamics of the fluid and elastic domains, demonstrate fabrication techniques, and present experimental results validating the two cases’ theoretical model.

This work also introduces the development of two types of fluid-actuated quasi-static crawling soft robots. The first is an inchworm crawling soft robot, which exploits a common locomotion mechanism in soft robots and invertebrate creatures. We modeled inchworm crawling locomotion by approximating it with an equivalent articulated robot with elastic joints and utilizing the analysis to investigate inputs on crawling gaits’ performance. Second, we show the use of embedded pneumatic networks as a mechanism to mimic nature and generate continuous traveling waves in soft-robots by standard fabrication techniques and having only two input controls. We propose both robots’ theoretical models, which guide the design, fabrication, and optimization. Finally, we present experiments and data analysis of measurements that agree with the theoretical models.