Jun Zhang: Assistive robotic exosuit

Title

Design and testing of an assistive robotic exosuit driven by artificial muscles

Mentor

Jun Zhang

Department

Mechanical Engineering

Biosketch

Jun Zhang is an assistant professor in the Department of Mechanical Engineering at the University of Nevada, Reno. His research interests lie in the intersection of control theory, robotics, and artificial muscles. In particular, he is interested in design, modeling, and control of artificial muscles with applications to soft robots, assistive robots and microelectromechanical systems.

He worked as a postdoctoral scholar at the University of California, San Diego from January 2016 to August 2018. He received the Ph.D. degree in electrical and computer engineering from Michigan State University in 2015, and the B.S. degree in automation from the University of Science and Technology of China, Hefei, China, in 2011. He was the recipient of the Student Best Paper Competition Award at the ASME Conference on Smart Materials, Adaptive Structures, and Intelligent Systems (SMASIS 2012), and the Best Conference Paper in Application Award at the ASME Dynamic Systems and Control Conference (DSCC 2013), and was named the Electrical Engineering Outstanding Graduate Student at Michigan State University for 2014-2015.

He is committed to mentoring Freshman, Sophomores, underrepresented populations and first generation students. Since 2016, he has supervised 20 undergraduate students and 2 high school students, including three females, five from underrepresented groups, and many first generation students. In 2019 Summer, he mentored Ryan Coulter, a Sophomore in ME UNR on soft robots and artificial muscles supported by National Science Foundation (NSF). His previous undergraduate students won NASA Space Grant Consortium scholarships, Nevada Undergraduate Research Awards, and many pursued graduate school education.

Project Overview

Conventional robots are often heavy and bulky with rigid gears, shafts, and linkages. Unlike electric motors, artificial muscles can generate straight contractions and elongations without complicated structures, just like how our biological muscles work. They offer many advantages over conventional rigid actuators (e.g., electric motors), i.e., high power-to-weight ratio, high force-to-weight ratio, inherent compliance, and all without complex linkages. Robotic devices moved with artificial muscles are thus compliant, lightweight, and compact. Robotic artificial muscles have shown strong potential as driving mechanisms for novel robotic applications such as robot manipulators, biomimetic robots, robotic prosthetics and exoskeletons, and soft robots. However, their full utilization is often challenged by the low strain and low force.

In this project, we will develop smart robot assistive exosuits by using a new muscle technologies - twisted string actuators (TSAs). TSAs consist of two strings attached to a motor on one end and a load on the other end. The motor's rotation twists the strings around themselves, generating linear actuation. First, the mechanical and electrical design of the robotic exosuit will be conducted. Second, the robotic exosuit and the TSAs will be manufactured. Last, the robotic exosuit will be assembled and tested for assisting hand/shoulder movements. The performance, such as the range of motion, the maximum assistive force will be characterized and analyzed. This study contributes to the design and implementation of lightweight and compliant assistive robot devices. The project involves machine and robot design, 3D printing, microcontroller programming, and mechanical and electrical testing.