Kwang-Kyu Lee’s scientific contributions

This paper proposes a compact embedded motor controller that can be mounted in a robot arm. Three different control modes are implemented in the controller: torque, velocity, and position. It supports EtherCAT network for real-time control whose control frequency is faster than 1kHz for 18 network nodes under Linux Xenomai operating system. The compact controllers are mounted inside an 18-DOFs dual-arm telepresence robot for smart shape design. Finally, the robot is connected with a master haptic device Omega-6 and showed successful tele-operation performance.

Three worlds are integral to our daily life: the real world, virtual world, and remote world. In the paper, there is proposed coexistent space where networked users can communicate, interact, and collaborate together by exchanging 4D+ sensation, human intension, and emotion. The 4D+ sensation includes 3D vision, 3D sound, force and torque, touch, and movements. The coexistent space is generated by seamless integration of real, virtual, and remote worlds while networked users experience the feeling of coexistence through 4D+ bi-directional interaction. Initial software framework and experimental results for interaction between multiple remote users are shown successfully.

In this paper, we present a modeling and control method for a single-port access robot developed by our robotics group at the Samsung Advanced Institute of Technology. The surgical robot consists of a snake-like 6-degree-of-freedom (DOF) guide tube, two 7-DOF tools, a 3-DOF stereo camera, and a 5-DOF slave arm. The robot is capable of reaching various surgical sites inside the abdominal cavity from a single incision on the body. To estimate the workspace and control the guide tube to a desired location, we first obtain the forward kinematics model of the guide tube and then propose a Cartesian-level controller. The wire actuation mechanism for the tools exhibit nonlinear backlash behavior because of wire compliance and friction between the wire and Teflon-coated conduit. We compensate for the backlash in the tool joints by adding the backlash inverse with smoothing term as a feedforward term.