Origami-Inspired Hexapod

Foldable HexapodThis research project focuses on the development of a lightweight origami-inspired foldable hexapod robot platform. Taking advantage of origami techniques in design, the robot can be fabricated and assembled in less than one hour from scratch. In order to increase the fabrication process and reduce the final cost, the crease pattern of the robot includes built-in fasteners to eliminate the need of any external screws and nuts. The locomotion engine of the platform composes of two 6-bar mechanisms. Each mechanism drives three feet of the robot through an optimized gait sequence. Design flexibility, ease of fabrication, and low cost make the robot suitable as an agent for swarm objectives. Experimental results of the robot show a maximum forward speed of 5 body lengths per second and maximum angular velocity of 1 revolution per second. The final prototype weighs only 42 grams.

Members: Siamak Faal, Fuchen Chen, Shadi Tasdighikalat

• S.G. Faal, F. Chen, W. Tao, M. Agheli, S. Tasdighikalat, C.D. Onal, "Hierarchical Kinematic Design of Foldable Hexapedal Locomotion Platforms", ASME Journal of Mechanisms and Robotics, 8:011005-1, (2016).
• C.D. Onal, M.T. Tolley, R.J. Wood, D. Rus, "Origami-Inspired Printed Robots", IEEE/ASME Transactions on Mechatronics, (2015).
• M. Agheli, S.G. Faal, F. Chen, H. Gong, C.D. Onal, "Design and Fabrication of a Foldable Hexapod Robot Towards Experimental Swarm Applications", IEEE International Conference on Robotics and Automation (ICRA), (2014).
• D.E. Soltero, B. Julian, C.D. Onal, D. Rus, "A Lightweight Modular 12-DOF Print-And-Fold Hexapod", IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), (2013).
• C.D. Onal, R.J. Wood, D. Rus, "An Origami-Inspired Approach to Worm Robots", IEEE/ASME Transactions on Mechatronics, 18 (2), 430-438 (2013).


Soft Robotic Snake

FEAWe developed a new generation of fluidic elastomer actuators (FEAs) that offer bidirectional bending as motion segments of a pressure-operated soft robotic snake. Our prior work on FEAs has identified a number of limitations, namely a high center of gravity, narrow base, slow dynamics, and a small range of pressure inputs. We developed two versions of FEAs based on an improved design concept with different geometric parameters and characterized their dynamic response under a custom visual tracking system. Compared with the previous actuators, the FEAs developed in this work offer robust operation, safety at larger input pressure values, faster response, lower center of gravity and a flat bottom for better compatibility for snake-like undulatory locomotion.

For a mobile robot undergoing serpentine locomotion, an accurate dynamic model is a fundamental requirement for optimization, control, navigation, and learning algorithms. Such algorithms can be readily implemented for traditional rigid robots, but remain a challenge for nonlinear and low-bandwidth soft robotic systems. Our work addresses the theoretical modeling of the dynamics of a pressure-operated soft snake robot. A general framework is detailed to solve the 2D modeling problem of a soft snake robot, which is applicable to most pressure-operated soft robots developed by a modular kinematic arrangement of bending-type fluidic elastomer actuators. The model is simulated using measured physical parameters of a soft snake robot prototype. The theoretical results are verified through a detailed comparison to locomotion experiments on a flat surface with measured frictional properties.

Members: Ming Luo, Selim Ozel, Weijia Tao

• M. Luo, W. Tao, F. Chen, T.K. Khuu, S. Ozel, C.D. Onal, "Design Improvements and Dynamic Characterization on Fluidic Elastomer Actuators for a Soft Robotic Snake", IEEE International Conference on Technologies for Practical Robot Applications (TePRA), (2014).
• M. Luo, M. Agheli, C.D. Onal, "Theoretical Modeling and Experimental Analysis of a Pressure-Operated Soft Robotic Snake", Soft Robotics, 1(2):136-146 (2014).
• C.D. Onal, D. Rus, "Autonomous Undulatory Serpentine Locomotion Utilizing Body Dynamics of a Fluidic Soft Robot", Bioinspiration & Biomimetics, 8 (2), 026003 (2013).