Tianyu Wang

I am a PhD student in Robotics at Institute for Robotics and Intelligent Machines , Georgia Tech (GT), advised by Prof. Daniel Goldman. I am a member of Complex Rheology And Biomechanics (CRAB) Lab, my current research focuses on biologically inspired limbless and legged robot locomotion in complex environments. My research interests include bio-inspired robots and their robophysical model developing, locomotion principle and mechanics modeling, and geometric and dynamic motion planning and control.

Prior to this, I received my Master degree in Mechanical Engineering from Carnegie Mellon University (CMU), advised by Prof. Howie Choset. I was a member of Biorobotics Lab, working on motion planning and compliant control for snake robot locomotion.

I received my BS degree in Electrical and Computer Engineering from the University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University (SJTU). I was a member of Soft Robotics and Biodesign Lab, led by Prof. Guoying Gu.

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Research Projects
project image The Omega Turn: A Biologically-Inspired Turning Strategy for Elongated Limbless Robots
Tianyu Wang*, Baxi Chong*, Kelimar Diaz, Julian Whitman, Hang Lu, Matthew Travers, Daniel I. Goldman, Howie Choset (*equal contribution)
IEEE International Conference on Intelligent Robots and Systems (IROS), 2020

Snake robots can locomote through tightly packed spaces, but turning effectively within unmodelled and unsensed environments remains challenging. Inspired by a behavior observed in the nematode C. elegans, we propose a novel in-place turning gait for elongated limbless robots. To simplify the control of the robots' many internal degrees-of-freedom, we introduce a biologically-inspired template in which two traveling waves are superposed in the same plane, producing an in-plane turning motion. We call this gait an omega turn. The omega turn gait arises from modulating the wavelengths and amplitudes of the two traveling waves. We experimentally test the omega turn on a snake robot, and show that this turning gait outperforms previous turning gaits: it results in a larger angular displacement and a smaller area swept by the body over a gait cycle, allowing the robot to turn in narrower spaces.

project image project image Frequency Modulation of Body Waves to Improve Performance of Limbless Robots
Baxi Chong, Tianyu Wang, Jennifer Rieser, Abdul Kaba, Howie Choset, Daniel I. Goldman
Robotics: Science and Systems (RSS), 2020
presentation / pdf / video / bibtex

Sidewinder rattlesnakes generate movement through coordinated lateral and vertical traveling waves of body curvature. Previous biological and robotic studies have demonstrated that proper control and coordination of these two waves enables robust and versatile locomotion in complex environments. However, the propagation of the vertical wave, which sets the body-environment contact state, can affect static stability and cause undesirable locomotion behaviors, especially when for movement at low speeds. Here, we propose to stabilize gaits by modulations of the spatial frequency of the vertical wave, which can be used to tune the number of distinct body-environment contact patches (while maintaining a constant overall contact area). These modulations act to stabilize configurations that were previously statically unstable and therefore, by eliminating dynamic effects such as undesired turning, broaden the range of movements and behaviors accessible to limbless locomotors at a variety of speeds. Specifically, our approach identifies, for a given lateral wave, the spatial frequency of the vertical wave that statically stabilizes the locomotor and then uses geometric mechanics tools to identify the coordination (i.e., the phase shift) between the vertical and lateral waves that produces a desired motion. We demonstrate the effectiveness of our technique on the locomotion of both robotic and robophysical systems.

project image Directional Compliance in Obstacle-Aided Navigation for Snake Robots
Tianyu Wang, Julian Whitman, Matthew Travers, Howie Choset
American Control Conference (ACC), 2020
presentation / arxiv / pdf / video / bibtex

Snake robots have the potential to maneuver through tightly packed and complex environments. One challenge in enabling them to do so is the complexity in determining how to coordinate their many degrees-of-freedom to create purposeful motion. This is especially true in the types of terrains considered in this work: environments full of unmodeled features that even the best of maps would not capture, motivating us to develop closed-loop controls to react to those features. To accomplish this, this work uses proprioceptive sensing, mainly the force information measured by the snake robot’s joints, to react to unmodeled terrain. We introduce a biologically-inspired strategy called directional compliance which modulates the effective stiffness of the robot so that it conforms to the terrain in some directions and resists in others. We present a dynamical system that switches between modes of locomotion to handle situations in which the robot gets wedged or stuck. This approach enables the snake robot to reliably traverse a planar peg array and an outdoor three-dimensional pile of rocks.

project imageproject image Programmable design of soft pneu-net actuators with obliquechambers can generate coupled bending and twisting motions
Tianyu Wang*, Lisen Ge*, Guoying Gu   (*equal contribution)
Sensors and Actuators A: Physical, 2018
pdf / video 1 / video 2 / bibtex

Soft pneumatic network (pneu-net) actuators are widely employed for achieving sophisticated motions. However, to produce bending and twisting simultaneously in a single pneu-net actuator is challenging. In this paper we present a programmable design to enable pneu-net actuators to achieve such complex motions. This achievement is mainly owing to tuning a structure parameter, the chamber angle. Through finite element analysis and experimental verification, variation trends of bending and twisting motions with respect to the chamber angle are investigated. Additionally, deformation characteristics of actuators are demonstrated by depicting configurations of actuators and some grasping tests. By adjusting the chamber angle, the motion of pneu-net actuators is explored into 3D space and becomes more sophisticated and dexterous. This programmable design method guides the design of pneu-net actuators, making them promising candidates for more complicated and advanced applications.

Last update: 7/5/2020

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