M.Sc Thesis

M.Sc StudentPukshansky Michael
SubjectMinimialistic Fluid-Driven Actuation of Multi-Stable
Soft Robots
DepartmentDepartment of Autonomous Systems and Robotics
Supervisors ASSOCIATE PROF. Yizhar Or
Full Thesis textFull thesis text - English Version


Soft robotics is an emerging field of research greatly inspired by nature, which focuses on analysis and design of robots with flexible structure that can deform and change shape and dimensions continuously.

In this work we focus on fluid-driven elastic actuators. In those actuators, fluid chambers are embedded in an elastic structure. The actuation is achieved by controlling the pressure or the flow rate at the fluid-inlets of the structure. For complicated actuation (e.g. three-dimensional movement or locomotion) usually several separated control inlets are used. In this work, we are minimizing the number of controlling inlets by: 1. Utilizing dynamic effects of viscous flow. 2. Using multi-stable elastic structures.

Experiments were conducted to study the behavior of Frusta - multi-stable structures also known as “bending straw”. This structure has many different equilibrium states. By controlling the pressure of an entrapped fluid in the frusta, we show that it is possible to switch between different equilibrium states. Connecting the flow inside several different frusta and using a high-viscosity liquid allowed us to present two straw-based robots: 1. One dimensional crawling straw-based robot. 2. Three-dimensional parallel straw-based robot. Both of them are controlled using only one inlet pressure.

Soft robots are expected to be especially useful in in man-machine interfaces, locomotion on different terrains and through narrow spaces, robotic minimally invasive surgery and more. This work helps to simplify the hardware needed for controlling such robots.