Thesis
Variable stiffness structures via mechanics modification and antagonistic actuation in soft robotic materials
Washington State University
Master of Science (MS), Washington State University
05/2020
DOI:
https://doi.org/10.7273/000004097
Handle:
https://hdl.handle.net/2376/124716
Abstract
The soft robotics approach seeks to provide the efficiency and autonomy of robots while using soft materials that are safe for interaction with humans and delicate objects. The inherent weakness of flexible materials renders ordinary usage of soft materials inadequate for robots that need to exert large forces. In this paper, two classes of mechanisms for variable stiffness structures are explored: intrinsic variable stiffness and dual antagonistic actuation. This work proposes designs and modeling strategies for variable stiffness structures that incorporate smart materials (to enable modification of intrinsic mechanical properties), geometric patterning of low melting point materials (to enable directional stiffness control), and pneumatic/shape memory alloy antagonistic actuation (to enable independent control of stiffness and bending). Whereas other researchers have focused on controlling the magnitude of stiffness in soft materials, this paper also explores soft robotic structures with directional stiffness control. The mechanical properties of the materials are tested via tension, compression, and 3-point bend tests. Kinematic modeling of the patterned structure relies on the product of exponentials method for serial link robots, then incorporates tendon forces and selectable axes for the kinetic relationships. A finite element model is constructed in MATLAB to predict the configuration of the pneumatic/shape memory alloy actuator based on measured material properties. Each of the proposed designs are fabricated and tested to demonstrate their variable stiffness capabilities and compare with modeling results.
Metrics
43 File views/ downloads
30 Record Views
Details
- Title
- Variable stiffness structures via mechanics modification and antagonistic actuation in soft robotic materials
- Creators
- Emily A. Allen
- Contributors
- John Paul Swensen (Advisor) - Washington State University, School of Mechanical and Materials Engineering
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900890786901842
- Language
- English
- Resource Type
- Thesis