Dr. Jee-Hwan Ryu is an Associate Professor in the Department of Civil and Environmental Engineering at Korea Advanced Institute of Science and Technology (KAIST). He received the B.S. degree in mechanical engineering from Inha University, South Korea, in 1995, and the M.S. and Ph.D. degrees in mechanical engineering from KAIST, South Korea, in 1997 and 2002, respectively. From 2002 to 2003, he worked as a post-doc researcher in the department of electrical engineering at the University of Washington, and at the similar time, he was also affiliated with the institute of robotics and mechatronics in DLR as a visiting scientist. He joined KAIST in 2019 as an associate professor. Prior to that, he was a professor in the department of mechanical engineering at KOREATECH (2005-2019), and a research professor in the department of electrical engineering at KAIST (2003-2005). His research interests include haptics, telerobotics, exoskeletons, and autonomous vehicles. He has received several awards including IEEE Most Active Technical Committee Award as a Co-chair of TC Haptics in 2015, Best poster award in 2010 IEEE Haptic Symposium. He has been served as an Associate Editor in IEEE Transactions on Haptics, and since 2017, he has been serving as an Associate Editor-in-chief in World Haptics Conference. He was involved in many international conference organizations, and especially, he has been served as a general chair of AsiaHaptics2018.

Talk # 1

Twisted String Actuator and its Application to Wearable Soft Exosuit 

Even with the recent enormous advancement of software and hardware technology in robotics, it is quite frustrating that most of the exoskeletons are still quite heavy and too rigid to be wearable. One of the major bottleneck is the limited power-to- weight ratio and the rack of softness of actuators. In particular, rigid and heavy mechanical transmission system has been dragging down the advancement of the wearable exoskeleton technology. In this presentation, I’m going to introduce some of the recent development of Twisted String Actuator (TSA) as an effort to increase the power-to-weight ratio and softness of the actuator. Typically, I want to focus on basic mathematical model, several extended modules and implementations of this. I will also touch several mechanisms to overcome the limitation of the TSA such as nonlinearity and low contraction speed. In additional to the basics of TSA, as an example of the implementation, I will be showing a soft upper limb exosuit together with several different version of soft hand exoskeleton systems.

Talk # 2

How Stiff or Light we can Reach: Time-domain Passivity Approach for Stable and Transparent Haptic Interaction

The addition of haptic capability dramatically increases the immersiveness of human- robot interaction in AR/VR or teleoperation. That is because the sense of touch conveys rich and detailed information about virtual or remote environments. However, it has been challenging to provide immersive feelings of touch due to the limited range of impedance that a haptic device can display without any stability issue. In this presentation, we will be discussing how to realize stable and immersive human-robot haptic interaction, in particular from the aspect of tight haptic coupling between human and virtual/remote environment. Several state-of-the-art control methods, such as Time Domain Passivity Approach, Successive Stiffness Increment, Successive Force Augmentation method will be introduced, which have been developed for increasing the impedance range of both impedance type and admittance type haptic interfaces for the interaction with virtual objects and remote environments. A stable bilateral teleoperation method to overcome time varying communication delay will be introduced as well with several implementation examples with DLR space telerobotic systems.